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  • 1
    Electronic Resource
    Electronic Resource
    Bestandsverminderung bei verwilderten Haustauben Teil 1 Bilanz mitteleuropäischer Stadtverwaltungen (1999)
    Springer
    Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz 42 (1999), S. 911-921 
    Details
    ISSN: 1437-1588
    Keywords: Schlüsselwörter ; Verwilderte Haustauben (Columba livia domestica) ; Bestandsregulierung ; Stadthygiene ; Gesundheitsschutz ; Ökologisches Management ; Key words ; Feral pigeons ; Street pigeons (Columba livia domestica) ; Population reduction ; Habitat manipulation ; Urban hygiene ; Public health ; Bird management strategies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The report, in two parts, sums up the findings of a survey covering 52 cities in Central Europe. Most administrations have imposed a ban on feeding street pigeons, but this has been more or less unsuccessful. Information campaigns were used on a large scale, along with more controversial methods such as catching the birds or shooting them down, providing pigeon houses, administering hormone preparations, chemosterilization, and exclusion from buildings. Few attempts were made to reduce the number of breeding places. Population reduction by poisons or natural enemies seems to be negligible. The findings of the survey are compared with results reported in the specialist literature, followed by a discussion of the ecological, hygienic and legal aspects, including animal protection, pest control, and public health. The strategy proposed to improve the present situation, which is found unsatisfactory in many respects, is to organize along the principles of ecological management. By optimizing the available options and following scientific criteria, it aims to combine those methods which appear most promising under local conditions. Any drawbacks are to be compensated by the enhancement of positive elements to give the best possible overall results.
    Notes: Zusammenfassung Der zweiteilige Bericht faßt die Ergebnisse einer Umfrage zusammen, bei der sich die Verwaltungen von 52 mitteleuropäischen Städten zum Straßentaubenproblem geäußert haben. Überwiegend versucht man mehr oder minder erfolglos, eine Bestandsverminderung durch Taubenfütterungsverbot zu erreichen. Häufig wird auch von Bürgerbelehrungen und Informationskampagnen berichtet. Ferner spielen Fangaktionen, Taubenhäuser, Hormonpräparate und Chemosterilantien, Abschuß und Absperrmaßnahmen an Gebäuden eine meist ambivalente Rolle. Bei der Verminderung der Brutplatzangebote sind nur schwache Bemühungen erkennbar. Natürliche Feinde (Greifvögel) scheinen in den wenigsten Städten eine Rolle bei der Reduzierung von Straßentauben zu spielen. Vergiftungen werden offenbar nicht mehr vorgenommen. Die Erfahrungen der Kommunen werden mit den in der Fachliteratur vorliegenden Ergebnissen verglichen. Kommentare aus ökologischer und hygienezoologischer Sicht berücksichtigen die rechtlichen Grundlagen von Tierschutz, Schädlingsbekämpfung und Gesundheitsvorsorge. Um die insgesamt noch sehr unbefriedigende Situation bei der Bestandsverminderung von verwilderten Haustauben zu verbessern, wird ein Strategieprogramm nach den Organisationsprinzipien des „ökologischen Managements” vorgeschlagen. Hierzu sollten sämtliche anwendbaren Möglichkeiten nach wissenschaftlichen Kriterien optimiert und den jeweils stadtspezifischen Umständen entsprechend so miteinander kombiniert werden, daß methodische Nachteile durch die Vorteile anderer Komponenten ausgeglichen werden und das Gesamtkonzept nach dem Verstärkerprinzip Optimalergebnisse erzielt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001030050221
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  • 2
    Electronic Resource
    Electronic Resource
    Das Frankfurter Bleiprojekt Maßnahmen zur Einhaltung des Grenzwertes für Blei im Trinkwasser (1999)
    Springer
    Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz 42 (1999), S. 902-910 
    Details
    ISSN: 1437-1588
    Keywords: Schlüsselwörter ; Trinkwasser ; Bleileitungen ; Key words ; Drinking water ; Lead pipes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary On 3.11.1998 the Drinking Water Directive passed the European Parliament. This new directive will lower the current limit value for lead in Germany from 0,040 mg/l to 0,025 mg/l in 2003 and to 0,010 mg/l in 2013. Since there are still around 7800 premises with plumbing-systems containing lead-pipes in Frankfurt, the Stadtgesundheitsamt started the „Frankfurt Lead-Project” in 1997. Aim of the project was the investigation and, if necessary, the order to exchange all concerned plumbing systems. The owners of the buildings are liable to a fee for these measures of the local public health service, thus covering of the costs should be attainable. Within the project 3 to 5 water probes from each concerned building were sampled, to take the stagnation-problem into account. The drinking water of 50% of the investigated flats reached the EG-parametric value of 0,01 mg/l, which has to be transferred into national law from 2013 on the latest. Houses with plumbing-systems not containing lead were part of this sample. A sample of houses with only lead containing plumbing systems would result in considerably higher values. The mean lead-concentration after a stagnation-period of 3 hours was 0,034 mg/l and therefore significantly exceeded the EG-parametric value of 0,025 mg/l. Experts agree that the future EG-parametric values can not be met with special water treatments, but only by replacement of lead pipes by pipes composed of other suitable materials. Even pipe-coating techniques can not be recommended at this time. To our experience the new EG-parametric-value for lead of 0,025 mg/l, which has to be transferred into national law by the european member states from 2003 on, will require the sanitation of nearly every house with a lead-containing plumbing system. All the more so because the EG-parametric-value of 0,10 mg/l will become effective from 2013 on, what factually equals a prohibition of lead-pipes. Considering the time given by the EG-Drinking Water Guideline and the experience reported here we conclude that compliance with the new EG-parametric values would not be possible for most of the German cities and communities having a lead-pipe problem. It is foreseeable therefore, that the Federal Republic of Germany will have to face complaints for non-compliance with the parametric value from the European Commission. Based on the experiences with the lead-project we would recommend the prohibition of lead pipes whithin domestic distribution systems as an appropriate measure to achieve compliance with the parametric value for lead. Such a prohibition would make it possible to meet the parametric value for lead, create a reliable legal situation for both consumers and owners of the concerned plumbing systems, save considerable expenses for staff and laboratory tests, make the exchange of lead-containing installations easy to plan and would avoid conflicts about the interpretation of monitoring results.
    Notes: Zusammenfassung Durch die am 3.11.1998 vom Europäischen Parlament verabschiedete Richtlinie des Rates der Europäischen Gemeinschaft über die Qualität von Wasser für den menschlichen Gebrauch muß eine Absenkung des Bleigrenzwertes in Deutschland von derzeit 0,040 mg/l auf 0,025 mg/l bis spätestens zum Jahr 2003 und auf 0,010 mg/l bis spätestens zum Jahr 2013 erfolgen. Da in Frankfurt a.M. bekannt war, daß noch ca. 7800 Liegenschaften mit bleihaltigen Hausinstallationen ausgestattet sind, wurde ab 1997 im Stadtgesundheitsamt das „Blei-Projekt” gestartet, mit dem eine Untersuchung und ggf. erforderliche Sanierung aller betreffenden Häuser binnen max. zehn Jahren ab 1996 unter dem Aspekt der Kostendeckung durchgesetzt werden soll. Pro untersuchtem Haus wurden mehrere Proben entnommen, um das Stagnationsproblem adäquat zu berücksichtigen. In 50% der von uns untersuchten Wohnungen, unter denen sich auch Hausinstallationen ohne Bleileitungen befanden, wurde der ab dem Jahr 2013 geltende Grenzwert von 0,010 mg/l bereits erreicht. Bei einer nur aus bleihaltigen Hausinstallationen bestehenden Stichprobe ist aufgrund unserer Daten zu erwarten, daß dieser Wert sogar deutlich überschritten würde. Der Mittelwert der Leitungsproben nach 3 Stunden Stagnation überschreitet mit 0,034 mg/l den ab dem Jahr 2003 geltenden Grenzwert von 0,025 mg/l klar. Aus der Fachdiskussion ist bekannt, daß sich die zukünftigen Grenzwerte nicht mit Aufbereitungsmaßnahmen wie Phosphatierung u.ä. einhalten lassen werden, sondern daß der Austausch der Bleileitungen gegen Leitungen aus geeigneten Werkstoffen der einzig in Frage kommende Sanierungsweg ist. Auch mit Innenbeschichtungen arbeitende Sanierungstechniken können derzeit nicht empfohlen werden. Schon die Festsetzung des Trinkwasser-Grenzwertes für Blei von zunächst 0,025 mg/l ab dem Jahr 2003 bedeutet daher, daß nahezu jede bleihaltige Hausinstallation bis dahin durch vollständiges Austauschen der Bleirohre saniert werden muß. In jedem Fall gilt dies für die Einführung des Parameterwertes von 0,010 mg/l ab dem Jahr 2013, was faktischen einem Verbot von Bleileitungen gleichkommt. Aus den gegebenen Fristen und den hier gemachten Erfahrungen hinsichtlich der benötigten Bearbeitungszeiten ist die Erkenntnis abzuleiten, daß ein Vollzug der Trinkwasserverordnung ohne ein möglichst auf klare europaweite Rechtsvorschriften gegründetes Verbot in den meisten betroffenen Bundesländern, Kreisen und kreisfreien Städten nicht möglich sein wird und somit die seitens der die Bundesrepublik Deutschland als EG-Mitgliedsstaat eingegangenen Verpflichtung zur Einhaltung des Parameterwertes für Blei nicht erfüllt werden kann. Ein Verbot für Bleileitungen würde die Einhaltung des Parameterwertes ermöglichen, Rechtsklarheit sowohl für die Verbraucher als auch für die Eigentümer von Hausinstallationen bringen, erhebliche Mittel für Untersuchungs- und Verwaltungskosten einsparen lassen, die ohnehin unumgängliche Sanierung von bleihaltigen Hausinstallationen für die Eigentümer besser planbar machen sowie Rechtsstreitigkeiten über die Interpretation von Meßwerten vermeiden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001030050220
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  • 3
    Electronic Resource
    Electronic Resource
    Therapie des Knorpelschadens (1999)
    Springer
    Arthroskopie 12 (1999), S. 279-288 
    Details
    ISSN: 1434-3924
    Keywords: Schlüsselwörter ; Knorpelschaden ; Knie ; Knorpelregeneration ; Key words ; Cartilage damage ; Knee ; Cartilage regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Damage to articular cartilage is a common problem. Damage to a joint surface can lead to premature arthritis. In this review the results of the different forms of therapy for cartilage damage such as lavage, drilling, microfracturing, abrasion arthroplasty, transplantation of osteochondral allografts, periosteal arthroplasty and autologous chondrocyte transplantation are introduced to the reader.
    Notes: Die Therapie des Knorpelschadens stellt ein allgemeines Problem dar. Beschädigte Knorpeloberflächen können zur frühzeitig auftretenden Arthrose führen. In dieser Übersichtsarbeit werden die einzelnen Therapieformen zur Behandlung von Knorpelschäden wie die Lavage, Knochenmarkstimulationstechniken (subchondrale Bohrung, Mikrofrakturierung, Abrasionsarthroplastik) sowie neuere Therapieformen wie die Transplantation autologer Knochen-Knorpel-Zylinder, die Periostlappenplastik und die autologe Chondrozytentransplantation mit bisherigen Ergebnissen vorgestellt. Der Leser soll somit einen Überblick über diese Verfahren erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001420050103
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  • 4
    Electronic Resource
    Electronic Resource
    Einfluß von zyklischer mechanischer Dehnung auf die Zellproliferation humaner Fibroblasten (1999)
    Springer
    Arthroskopie 12 (1999), S. 289-293 
    Details
    ISSN: 1434-3924
    Keywords: Schlüsselwörter ; Rehabilitation ; Humane Fibroblasten ; Zyklische mechanische Dehnung ; Zellproliferation ; Key words ; Rehabilitation ; Human fibroblast ; Cyclic strain ; Cell proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Experimental and clinical studies document the benefits of early controlled motion and loading in the treatment of musculoskeletal injuries. At the cellular level, dynamic strain plays a key role in cell stimulation and organization of the extracellular matrix. Although the positive effects of physical strain on tendon tissue are well known, little knowledge exists as to how mechanical strain affects tendon cells. The aim of the present study was to investigate in vitro the influence of cyclic strain on cell proliferation of human tendon fibroblasts. Human tendon fibroblasts from patellar tendon were cultured on silicone dishes. Cyclic biaxial strain was applied to the dishes in their long axis with third passage cells. A 5% strain magnitude and a frequency of 1 Hz were applied. The time of applied strain varied between 15, 30 and 60 min. After the fibroblasts were put under strain, the cells were tested for proliferation after 6, 12 and 24 h using incorporation of 5-bromo-2′-deoxy-uridine. As a control, cells were grown on silicone dishes but did not receive any strain. A biphasic response in proliferation was observed for the 15- and 60-min strain periods. At 6 and 24 h the proliferation was increased compared to the controls. The proliferation was decreased at 12 h. After a strain duration of 30 min the proliferation was inferior to that of the controls at all times measured. Application of mechanical stress to tendon fibroblasts results in an alteration of cellular proliferation, depending on the stress time. This study will contribute to an understanding of the cellular mechanism underlying the mechanical stimulation of tendon and ligament healing.
    Notes: Klinische und tierexperimentelle Studien haben den positiven Einfluß einer frühfunktionellen Behandlung nach Verletzungen des Binde- und Stützgewebes gezeigt. Dehnung ist dabei der zentrale Stimulus für reaktive Prozesse auf zellulärer Ebene. Zyklische mechanische Dehnung führt zu einer Reihe von Reaktionen, die für die Adaption von Zellen und Geweben an unterschiedliche Belastungen und für den Heilungsprozeß von Bedeutung sind. Ungeklärt ist jedoch, wieviel Dehnungsstreß notwendig ist. Ziel dieser Studie war, den Einfluß der Dauer von definierter zyklischer Dehnung auf die Zellproliferation von humanen Fibroblasten zu untersuchen. Fibroblasten wurden dazu aus Patellarsehnen isoliert und auf Silikonschalen kultiviert. Die Silikonschalen mit Zellen der 3. Passage wurden mit einem elektromechanischen Stimulationsgerät zyklisch mechanisch in der Längsachse gedehnt. Eine Dehnungsamplitude von 5% und die Frequenz 1 Hz wurden für alle Experimente gewählt. Die Dauer der zyklischen Dehnung wurde mit 15, 30 und ¶60 min verändert. Nach insgesamt 6, 12 und 24 h wurde der Versuch beendet. Zur Quantifizierung der Zellproliferation wurde die DNA-Synthese, d. h. der ¶Einbau von 5-Bromo-2′-deoxy uridine¶(BrdU) in die DNA gemessen. Als Kontrolle dienten humane Fibroblasten auf Silikonschalen ohne mechanische Dehnung. Nach 15 und 60 min zyklischer Dehnung zeigte sich ein biphasischer Verlauf hinsichtlich der Zellproliferation. Nach 6 und 24 h war eine Zunahme der Zellproliferation im Vergleich zu 12 h vorhanden. 30 min zyklische mechanische Dehnung hatte im Vergleich zur Kontrolle dagegen keinen positiven Einfluß auf die Zellproliferation. Zyklische mechanische Dehnung führt in Abhängigkeit von der Streßdauer zu Veränderungen bei der Zellproliferation. Die längere Streßdauer induziert potentiell Reaktionen, die eine protektive Wirkung für die Zellproliferation haben. Die zelluläre Streßantwort basiert jedoch auf komplexen Prozessen, deren Regulation und Modulation noch nicht geklärt sind. Das Verständnis der zellulären Reaktionen auf mechanische Dehnung ist von grundlegender Bedeutung für eine funktionelle Behandlung von Sehnen- und Bandverletzungen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001420050104
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  • 5
    Electronic Resource
    Electronic Resource
    Analyse traumatischer und degenerativer Knorpelläsionen des Kniegelenks (1999)
    Springer
    Arthroskopie 12 (1999), S. 294-298 
    Details
    ISSN: 1434-3924
    Keywords: Schlüsselwörter ; Knie ; Knorpelläsion ; Arthroskopie ; Knorpeltransplantation ; Key words ; Knee ; Cartilage lesion ; Arthroscopy ; Cartilage transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: The clinical application of cartilage repair procedures is currently being discussion. To define cartilage lesions with respect to localization, degree of cartilage damage, size, and etiology we retrospectively reviewed data from 4408 patients who had knee arthroscopies. Chondral lesions were divided into traumatic (n = 572, mean age 30.2 years; 13.2–52.7 years) and degenerative (n = 976, mean age 51.4 years; 27.1–79.9 years) lesions. All traumatic cartilage lesions were associated with isolated anterior cruciuate tear. The time interval between injury and arthroscopy was subdivided in patients with acute ¶anterior cruciate ligament tear (〈 6 weeks) or with chronic joint instability (〉 6 weeks). Isolated degenerative cartilage lesions were subdivided in patients aged ≤ 40 years and 〉 40 years. Patients with other associated lesions were excluded. Because we believe that patients with grade III cartilage lesions under the age of 40 years represent the ideal type of patient to receive cartilage or osteochondral transplantation, the data set was analyzed further to characterize these patients. In both groups (traumatic and degenerative) the medial femoral condyle and the medial tibial plateau were most affected. Grade III lesions increased in number and size in all compartments with age by about 2–3.5-fold. The medial tibial plateau showed a significantly higher alteration of about 13-fold in patients aged 〉 40 years. The two subgroups comprising acute and chronic anterior cruciate ligament tears did not demonstrate any statistically significant differences in any parameter. Potential candidates for cartilage grafting accounted for 82 patients (5.3%) on the medial femoral condyle and for 33 patients (2.1%) on the medial tibial plateau of all cartilage lesions (n = 1548 in this data set. In conclusion, we found no relationship between time of surgery and degree of traumatic cartilage lesions after anterior cruciate ligament tear. The development of grade III cartilage lesions in patients older than ¶40 years was significantly higher on the medial tibia plateau than in the other compartments. That means that extrinsic factors have more influence on the cartilage damage than genetically determined factors. In respect to the observation that most of the patients achieve a total knee arthroplasty because of osteoarthritis on the medial compartment, all cartilage reconstructive procedures should be focused on the medial compartment.
    Notes: Die Indikation zur Knorpeltransplantation bzw. zum Einsatz anderer biologisch rekonstruktiver Maßnahmen wird kontrovers diskutiert. Zur Bestimmung des Musters der Knorpelschädigungen im Kniegelenk war es Ziel dieser Studie, die Parameter Lokalisation, Schädigungsgrad und Größe in Abhängigkeit von der Ätiologie zu bestimmen. Es wurden 4408 Patienten mit Kniegelenkarthroskopien ausgewertet, bei denen bei 572 Patienten (Durchschnittsalter 30,2 Jahre; 13.2–¶52,7 Jahre) eine traumatische und bei 976 Patienten (Durchschnittsalter 51,4 Jahre; 27,1–79,9 Jahre) eine degenerative Knorpelschädigung vorlag. Den traumatische Knorpelläsionen wurden Patienten mit einem gesicherten Rotationsereignis und einer isolierten assoziierten vorderen Kreuzbandläsion zugeordnet. Diese Gruppe wurde entsprechend dem Zeitintervall zwischen Ereignis und Arthroskopie in akute (〈 6 Wochen) und chronische (〉 6 Wochen) Zustände unterteilt. Den degenerativen Knorpelläsionen wurden Patienten mit einer isolierten Knorpelpathologie zugeordnet und nach dem Lebensalter ¶(≤ 40 Jahre oder 〉 40 Jahre) weiter differenziert. Patienten mit einer zusätzlichen pathologischen Veränderung wurden ausgeschlossen. Sowohl bei traumatischen als auch degenerativen Erkrankungen waren der mediale Femurkondylus und das mediale Tibiaplateau am häufigsten alteriert. Bei der altersabhängigen Untersuchung zeigte sich, daß erwartungsgemäß in allen Kompartmenten die Häufigkeit von Grad-III-Läsionen um den Faktor 2–3,5 zunahm, auf dem medialen Tibiaplateau jedoch um den Faktor 13. Der Vergleich von akuten mit längerzeitig bestehenden traumatischen Knorpelverletzungen erbrachte keinen statistisch signifikanten Unterschied in allen untersuchten Parametern. Insgesamt hatten nur 82 Patienten (5,3%) am medialen Femurkondylus und 33 Patienten (2,1%) am medialen Tibiaplateau eine Grad-III-Läsion, welche potentiell von allen Knorpelschädigungen (n = 1548) für eine Knorpeltransplantation in Frage kommen würden. Zusammenfassend ist zu schlußfolgern, daß ein Einfluß der Zeitdauer nach traumatischer Knorpelläsion mit assoziierter vorderer Kreuzbandläsion auf die untersuchten Parameter in dieser retrospektiven Untersuchung nicht nachgewiesen werden konnte. Die Entwicklung von degenerativ bedingten Grad-III-Läsionen nimmt am medialen Tibiaplateau im Vergleich zu den anderen Kompartmenten nach dem 40. Lebensjahr sprunghaft zu, so daß der Einfluß exogener Faktoren wahrscheinlicher ist als das alleinige Vorliegen einer anlagebedingten Minderbelastbarkeit des Knorpels. Im Zusammenhang mit der Beobachtung, daß die meisten Patienten aufgrund einer Varusgonarthrose endoprothetisch versorgt werden, sollte die Indikation für knorpelrekonstruierende Maßnahmen auf das mediale Kompartment fokusiert werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001420050105
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  • 6
    Electronic Resource
    Electronic Resource
    Arthroskopische Lysis und Lavage des Kiefergelenks zur Therapie von Diskusverlagerungen (1999)
    Springer
    Arthroskopie 12 (1999), S. 318-322 
    Details
    ISSN: 1434-3924
    Keywords: Schlüsselwörter ; Discus-articularis-Verlagerungen ; Arthroskopie ; Lysis & Lavage ; Key words ; Discus articularis ; Displacement ; Arthroscopy ; Lysis & Lavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Displacement of the discus articularis with and without repositioning represents a common pathological alteration of the temporomandibular joint (tmj). The primary clinical symptoms are pain and reduced jaw movement. Particularly in cases of long-term complaints, conservative treatment methods such as splint and physiotherapy often do not produce the desired results. For these patients, arthroscopy combined with lysis and lavage is the treatment of choice for diagnostic as well as therapeutic purposes. In our department we performed this surgery on a total of 23 patients with discus displacement. With this low-risk procedure we achieved a definite improvement in symptoms in 20 patients; 11 of those patients were eventually complaint-free. Additionally, we can report a general improvement in opening the mouth. Except for a slight postoperative soft-tissue swelling, no complications developed. Thus, we can conclude that arthroscopic lysis and lavage, a low-risk and minimally invasive procedure, should be preferred to open arthrotomy in the primary treatment of tmj-displacements.
    Notes: Verlagerungen des Discus articularis mit und ohne Reposition stellen eine oft zu beobachtende pathologische Veränderung des Kiefergelenks dar. Klinisch stehen dabei Schmerzhaftigkeit und Einschränkungen der Unterkieferbewegungen im Vordergrund. Häufig können diese Beschwerden gerade bei längerem Bestehen durch konservative Behandlungsmaßnahmen wie eine Schienen- oder Physiotherapie nur geringfügig beeinflußt werden. Die Arthroskopie eröffnet hier in Kombination mit einer Lysis und Lavage sowohl diagnostische als auch therapeutische Möglichkeiten. An unserer Klinik wurden insgesamt 23 Patienten mit einer Diskusluxation arthroskopiert. Bei 20 Patienten konnte mit diesem risikoarmen Eingriff eine deutliche Besserung der Symptomatik, bei 11 davon sogar eine subjektive Beschwerdefreiheit erzielt werden. Auch funktionell konnte z. B. eine generelle Verbesserung der Mundöffnung erzielt werden. Abgesehen von geringfügigen postoperativen Weichteilschwellungen waren keine Komplikationen zu verzeichnen. Als Konsequenz unserer Ergebnisse sollten die arthroskopische Lysis und Lavage als risikoarmes, minimalinvasives Verfahren bei Diskusluxationen des Kiefergelenks primär einer offenen Arthrotomie vorgezogen werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001420050109
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  • 7
    Electronic Resource
    Electronic Resource
    Mittelfristige Ergebnisse nach arthroskopischer Versorgung von skapholunären Bandverletzungen vergesellschaftet mit frischen distalen intraartikulären Radiusfrakturen (1999)
    Springer
    Arthroskopie 12 (1999), S. 313-317 
    Details
    ISSN: 1434-3924
    Keywords: Schlüsselwörter ; Radiusfraktur loco typico ; Skapholunäre Bandverletzungen ; Arthroskopisch assistierte Versorgung ; Mittelfristige Ergebnisse ; Key words ; Distal radius fracture ; Lesions of the scapholunate ligaments ; Wrist arthroscopy ; Midterm results
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Since 1993, 30 patients with acute intraarticular distal radius fractures have been treated under arthroscopic assistance. In 12 patients (40%) concomitant lesions of the intrinsic scapholunate ligaments were diagnosed. According to Geissler we found grade I-tear in one patient, grade II in three, grade III in six and grade IV in two patients. The eight individuals with grade III-and IV-lesions additionally revealed marked instablity intraoperatively. Therefore, operative stabilization was subsequently performed by temporary scapholunate and scaphocapitate arthrodesis. Seven patients out of this group (87.5%) were followed up clinically and radiologically 3 years postoperatively, on average. Clinical examination included range of motion tests and a subjective questionnaire concerning pain and working ability. Objective grip strength was measured using a Jamar tester and compared to the contralateral wrist. Radiological evaluation consisted of the posteroanterior and lateral view as well as stress views in radial and ulnar deviation. Data were evaluated by the Jakim and Cooney scoring system as well as the demerit point system by Gartland and Werley as modified by Sarmiento et al. According to Gartland, 100% of our patients showed an excellent result; these rates were 86% using the Jakim score and 60% using the Cooney scoring system. According to the subjective questionnaire all of the patients revealed an excellent or good result.
    Notes: Seit 1993 wurden an unserer Klinik 30 Patienten mit frischen distalen intraartikulären Radiusfrakturen arthroskopisch assistiert versorgt. Begleitende Verletzungen der skapholunären intrinsischen Bandverbindungen fanden sich bei 12 Patienten (40%). Entsprechend der Einteilung von Geissler fanden wir einmal eine Läsion vom Grad I, 3mal Grad II, 6mal Grad III und 2mal Grad IV. Die 8 Patienten mit den dritt- bzw. viertgradigen Läsionen zeigten intraoperativ zusätzlich eine deutliche Instabilität im Skapholunargelenk (SL-Gelenk), so daß eine temporäre skapholunäre bzw. skaphokapitäre Spickdrahtarthrodese in derselben Sitzung durchgeführt wurden. Aus dieser Gruppe konnten 7 Patienten (87,5%) nach durchschnittlich 3 Jahren klinisch und radiologisch nachuntersucht werden. Die klinische Untersuchung umfaßte ¶den Bewegungsumfang, subjektive Schmerzangaben sowie eine Befragung nach der Beschäftigung. Mittels Jamar-Dynamometer (Cedaron ® ) wurde die objektive Griffstärke beim Faustschluß im Vergleich beider Hände ermittelt. Zusätzlich wurden Röntgenbilder im a.-p.- und seitlichen Strahlengang sowie Streßaufnahmen in Radial- und Ulnarduktion angefertigt. Die erhobenen Daten wurden mittels der Scores von Jakim , Cooney sowie dem nach Sarmiento modifizierten Gartland-Werley-Score evaluiert. Nach Jakim zeigten 86% der Patienten ein sehr gutes oder gutes Resultat, nach Gartland 100% und nach Cooney 60% ein sehr gutes Ergebnis. In der subjektiven Befragung zeigten alle Patienten ein exzellentes oder gutes Ergebnis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001420050108
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  • 8
    Electronic Resource
    Electronic Resource
    French mirror site of the NPAC Visible Human Viewer: first year evaluation (1999)
    Springer
    Surgical and radiologic anatomy 21 (1999), S. 139-141 
    Details
    ISSN: 1279-8517
    Keywords: Anatomy ; Human ; Cross-section ; Computer-assisted instruction ; Education ; Medical
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The NPAC visible human viewer (NPAC VHV), graphical interface written in JAVA, freely accessible by the Web, allows the display of anatomic cross-sections of the Visible Human Project developed by the National Library of Medicine. In April 1997, the Medical Media Library of Lyons undertook the construction of a French-language mirror site of the NPAC VHV. The aim of this work is to evaluate first year utilisation of this site. From May 1st, 1997 to April 30th, 1998, the mirror site was consulted 34,752 times. In 45.14% of cases, the request came from France, in 4.42% of cases from Belgium, in 3.98% from Canada and in 2.12% from Switzerland. Other connections came either from a country responsible for fewer than 1% of connections or from unidentified computers. Data analysis showed a peak of connections between 15:00 and 17:00, and an increased number of connections from September to March 1998. The NPAC VHV is housed in 5 sites in the world. It is a software very simple to use. As the figures have no legends, it is more appropriate for group teaching than for self-teaching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00276-999-0139-1
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  • 9
    Electronic Resource
    Electronic Resource
    Forensic toxicological implication of acute fatal poisoning cases due to benfuracarb ingestion (1999)
    Springer
    International journal of legal medicine 112 (1999), S. 268-270 
    Details
    ISSN: 1437-1596
    Keywords: Key words Poisoning ; Benfuracarb ; Carbofuran ; Human ; Blood ; Urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Notes: Abstract We describe here three cases involving acute fatalities due to benfuracarb ingestion and the forensic toxicological implications. Benfuracarb, a carbamate insecticide and its main metabolite carbofuran, were detected using thin layer chromatography (TLC) and gas chromatography/mass spectrophotometry (GC/MS) after extraction with ethyl acetate and then quantified using gas chromatography (GC) equipped with NPD. The blood levels of benfuracarb and carbofuran were in the range of 0.30∼2.32 μg/ml and 1.45∼1.47 μg/ml, respectively. Benfuracarb was not detected in urine, but carbofuran was detected in the range of 0.53∼2.66 μg/ml.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004140050247
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  • 10
    Electronic Resource
    Electronic Resource
    Analysis of otolith chemistry in Nassau grouper (Epinephelus striatus) from the Bahamas and Belize using solution-based ICP-MS (1999)
    Springer
    Coral reefs 18 (1999), S. 171-178 
    Details
    ISSN: 1432-0975
    Keywords: Key words Otolith ; Chemistry ; ICP-MS ; Stock discrimination ; Epinephelus striatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  We examined the utility of otolith minor and trace element chemistry, assayed with inductively coupled plasma mass spectrometry (ICP-MS), as a means of delineating population structure in the Nassau grouper (Epinephelus striatus). We characterized the elemental composition of otoliths collected in 1993 from three locations in Exuma Sound, Bahamas and from Glover Reef, Belize in 1995. A single location in Exuma Sound was sampled in 1994 to test temporal variability in otolith composition. Five elements (Ca, Zn, Sr, Ba and Pb) were routinely detected, at levels significantly above background, by solution-based ICP-MS. Results from analysis of variance of elemental data, expressed as a ratio to Ca, indicated that there were no significant differences among the Exuma locations for any element, but significant variability was found between Glover Reef and the pooled Exuma localities for Zn/Ca, Sr/Ca and Ba/Ca ratios. Significant inter-annual differences at one Exuma Sound location was restricted to Ba/Ca ratios. Discriminant function analysis correctly classified 86% and 95% of the Belize and pooled Exuma sites, respectively. Otoliths from Belize were characterized by low Zn/Ca and high Ba/Ca and Pb/Ca ratios compared to otoliths from fish collected in Exuma Sound. Although differences in Ba levels may be related to upwelling at Glover Reef, more data are needed to definitely link otolith composition with regional differences in water chemistry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003380050176
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  • 11
    Electronic Resource
    Electronic Resource
    Neck-proprioceptive influence on auditory lateralization (1999)
    Springer
    Experimental brain research 125 (1999), S. 389-396 
    Details
    ISSN: 1432-1106
    Keywords: Key words Neck muscles ; Vibration ; Proprioception ; Sound localization ; Space perception ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The effect of transcutaneous vibration of the posterior neck muscles on the lateralization of dichotic sound was investigated in human subjects. Two-alternative forced-choice (left/right) judgements were made on acoustic stimuli presented with different interaural level differences via headphones during neck-muscle vibration. A shift of the subjective auditory median plane toward the side contralateral of vibration was found, indicating that the sound was perceived as shifted toward the side of vibration. The mean magnitude of the vibration-induced intracranial shift was 1.5 dB. The results demonstrate a neck-proprioceptive influence on sound lateralization and suggest that this proprioceptive input is used for a central-nervous transformation of auditory spatial coordinates onto a body-centered frame of reference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050695
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  • 12
    Electronic Resource
    Electronic Resource
    Motor plasticity induced by synchronized thumb and foot movements (1999)
    Springer
    Experimental brain research 125 (1999), S. 435-439 
    Details
    ISSN: 1432-1106
    Keywords: Key words Transcranial magnetic stimulation ; Plasticity ; Synchronization ; Motor system ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used focal transcranial magnetic stimulation to examine the effects of 120 synchronized thumb and foot movements on the motor output map of the right abductor pollicis brevis muscle (APB) (experiment 1). To evaluate the performance, the latencies between the onset of the electromyographic activity (EMG) of the two muscles were measured. As control, 120 asynchronous thumb and foot movements were performed (experiment 2). Exclusively in experiment 1, the center of gravity (CoG) of the output map moved medially in the direction of the foot representation area (mean 7 mm, P〈0.05) and returned into its original location within 1 h. In experiment 2, the CoG remained unchanged (mean displacement, 0.68 mm into a lateral direction; not significant). The effect in experiment 1 was independent of an improvement in performance. We conclude that a short-lasting training of synchronous movements induces modulations of motor output maps which probably occur due to interactions between hand and foot representation areas in the motor cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050700
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  • 13
    Electronic Resource
    Electronic Resource
    From molecule to mind: the role of experience in shaping olfactory function (1999)
    Springer
    Journal of comparative physiology 185 (1999), S. 297-304 
    Details
    ISSN: 1432-1351
    Keywords: Key words Odor coding ; Learning ; Enhanced sensitivity ; Rabbit ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The olfactory system is faced with a particular problem – the high dimensionality and inherent unpredictability of the chemical world. Most natural odorants encountered in everyday life are complex mixtures of many different volatiles. This means that from the outset the olfactory system has to contend with a great and often unpredictable diversity of molecules, making it difficult for stable primary features of the chemical world to be mapped onto the sensory surface. One solution to such unpredictability is provided by learning. Learning confers flexibility, enabling individuals of a given species to acquire and make use of the most appropriate information in a particular environment. Two examples of this are presented: learning of maternal odors in neonatal rabbits, including evidence that the sensory surface itself may be influenced by environmental conditions so as to enhance sensitivity to molecules of particular ecological relevance, and cross-cultural human studies suggesting that experience with everyday odors influences not only the way these are evaluated, but also their perceived intensity. It is concluded that an adequate understanding of odor coding and olfactory function will not be possible without taking such experience-dependent factors into account.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050390
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  • 14
    Electronic Resource
    Electronic Resource
    Wertigkeit der MRT bei traumatischer diskoligamentärer Instabilität der unteren HWS (1999)
    Springer
    Der Unfallchirurg 102 (1999), S. 942-948 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter ; HWS • Diskoligamentäre Instabilität • Funktionsaufnahmen • MRT ; Key words ; Lower cervical spine • Traumatic discoligamentous instabilities • Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The diagnostic accuracy of magnetic resonance imaging (MRI) for traumatic discoligamentous instabilities of the lower cervical spine was evaluated. MRI findings were correlated with the intraoperative findings. Fifteen patients were included in the study (11 males, 4 females, 33 years old on average). Indication for surgery was established with dynamic a. p. instability under fluoroscopy. In the operation, all patients showed complete traumatic rupture of the intervertebral disc. In contrast, MRI sequences revealed only eight mild and four severe disc lesions. Intraoperatively ruptures of the anterior and posterior longitudinal ligaments were verified in 7 patients each. MRI studies depicted only five ruptures of the anterior and three ruptures of the posterior longitudinal ligaments. In three cases MRI demonstrated no pathological findings (3 of 15 false-negative results). MRI and intraoperative findings showed no statistical correlation. MRI is of only limited value in diagnosing traumatic discoligamentous instabilities of the lower cervical spine.
    Notes: Zusammenfassung Die diagnostische Aussagekraft der Magnetresonanztomographie (MRT) bei frischer, traumatischer diskoligamentärer Instabilität der unteren Halswirbelsäule (HWS) wurde untersucht. Hierzu wurden die Befunde der MRT-Diagnostik mit den intraoperativen Befunden korreliert. Die Indikation zur Operation wurde bei nachgewiesener translatorischer a.-p.-Instablität im Röntgenbildwandler bei dynamischer Untersuchung gestellt; 15 Patienten (11 Männer, 4 Frauen, Durchschnittsalter 33 Jahre) wurden in die Studie eingeschlossen. Bei allen Patienten lag intraoperativ eine Ruptur des Discus intervertebralis vor. In der MRT-Diagnostik wurden hingegen bei 8 Patienten eine Bandscheibenprotrusion und bei 4 Patienten ein Bandscheibenprolaps nachgewiesen. Das vordere Längsband und das hintere Längsband waren intraoperativ bei jeweils 7 Patienten rupturiert. Im MRT-Befund war das vordere Längsband bei 5 Patienten und das hintere Längsband bei 3 Patienten rupturiert. Bei 3 von 15 Patienten (20 %) war die MRT unauffällig und damit falsch-negativ. Zwischen intraoperativem und MRT-Befund war keine statistisch signifikante Korrelation nachweisbar. Die MRT bietet daher für die Indikationsstellung zur Operation zum jetzigen Zeitpunkt keine ausreichende diagnostische Sicherheit bei der Evaluation traumatischer diskoligamentärer Instabilitäten der unteren HWS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050508
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  • 15
    Electronic Resource
    Electronic Resource
    Einfache und schnelle Methode zur Entfernung abgebrochener, unaufgebohrter Tibianägel (1999)
    Springer
    Der Unfallchirurg 102 (1999), S. 975-978 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter ; Implantatversagen • UTN • Entfernung des distalen Nagelanteils ; Key words ; Breakage of UTN • Extraction device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary By using UTN in the treatment of very distal tibia fractures delayed fracture-healing and pseudarthrosis with breakage of the nail are described. The removal of the distal solid part of the nail shows a special difficulty. We report about two cases of broken UTN in 1997. A simple extraction device to remove the distal part of the broken nail is demonstrated.
    Notes: Zusammenfassung Mit der Anwendung des unaufgebohrten Tibianagels (UTN) bei sehr distalen Tibiafrakturen wird zunehmend von verzögerter Knochenbruchheilung und Pseudarthrosen mit nachfolgendem Implantatversagen berichtet. Die Entfernung des soliden, distalen Nagelteils bringt besondere Schwierigkeiten mit sich. 1997 wurden in der BG-Unfallklinik Ludwigshafen 2 gebrochene, unaufgebohrte Tibianägel entfernt. Der Behandlungsverlauf sowie ein einfaches, überall verfügbares Verfahren zur zuverlässigen Entfernung des distalen Nagelanteils werden beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050513
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  • 16
    Electronic Resource
    Electronic Resource
    Die Lisfranc-Arthrodese nach Fehlheilung (1999)
    Springer
    Der Unfallchirurg 102 (1999), S. 918-923 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter ; Fehlheilung • Posttraumatische Arthrose • Lisfranc-Luxationsfrakturen • Lisfranc-¶Arthrodese • Maryland-Foot-Score ; Key words ; Residual deformity • Posttraumatic arthritis • Lisfranc-fracture-dislocation • Lisfranc Arthrodesis • Maryland Foot Score
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The causes of residual deformity with posttraumatic painful arthritis after tarsometatarsal (Lisfranc) fracture-dislocation with the need for correctional arthrodesis are in our experience (22 cases over 5 years) overseen injuries in one third, closed reduction and immobilisation or inadequate fixation technique with K-wires in another two thirds of cases. Foot malalignment and residual instability is assessed with weight-bearing radiographs of both feet, adduction/abduction stress films and CT scans for complex deformity. Correction is carried out via two longitudinal dorsal incisions, strict epiperiosteal preparation and debridement of the Lisfranc joint of all remaining cartilage, sclerosis and fibrous tissue. Reorientation begins, in the same manner as primary open reduction, with anatomical alignment of the second metatarsal base to the second cuneiform. Defects are filled with autologous bone grafting, stable fusion can be achieved with 3.5 mm cancellous compression screws. Full weight bearing is allowed in a modelled plaster shoe for 6 to 8 weeks. The functional medium-term results are convincing with 15 of 17 patients seen after 13 months of follow-up working full time. The Maryland Foot Score improved from 38.9 to 76.8 points in these patients.
    Notes: Zusammenfassung Fehlverheilungen mit konsekutiver posttraumatischer Arthrose nach Lisfranc-Luxationsfrakturen mit notwendiger reorientierender Lisfranc-Arthrodese gehen nach eigener Erfahrung (22 Fälle in 5 Jahren) in 1/3 der Fälle auf übersehene Verletzungen, in 2/3 der Fälle auf unzureichende geschlossene Repositionen und perkutane Spickdrahtosteosynthesen oder alleinige Retention im Gipsverband zurück. Belastungsaufnahmen beider Füße in 2 Ebenen sind zur Erkennung der Instabilität und Fehlverheilung unerläßlich, gegebenenfalls Vorfußabduktions- bzw. Adduktionsaufnahmen, eine Tomographie oder ein CT in 2 Ebenen. Bei veralteter homolateraler Lisfranc-Luxationsfraktur ist über 2 dorsale Längsinzisionen bei streng epiperiostaler Präparation das gesamte Lisfranc-Gelenk auszuräumen. Die Reorientierung beginnt – wie bei frischer Verletzung mit der anatomischen Einpassung der Metatarsale-II-Basis zum Cuneiforme II. Defekte sind mit autologer Spongiosa aufzufüllen, die Arthrodese mit 3,5er Kortikaliszugschrauben ist ausreichend. Die Nachbehandlung im Gipsschuh für 6–8 Wochen mit Vollbelastung hat sich bewährt. Der funktionelle Gewinn nach reorientierender Lisfranc-Arthrodese ist nach dem Maryland-Foot-Score von präoperativ 38,9 auf 76,8 Punkte postoperativ überzeugend.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050506
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  • 17
    Electronic Resource
    Electronic Resource
    Spontanheilung einer juvenilen Knochenzyste der Tibia nach pathologischer Fraktur (1999)
    Springer
    Der Unfallchirurg 102 (1999), S. 972-974 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter ; Juvenile Knochenzyste • Pathologische Fraktur • Konservative Therapie • Spontanheilung ; Key words ; Juvenile bone cyst • Pathological fracture • Conservative therapy • Spontaneous healing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Up to the present only few cases of spontaneous healing of juvenile bone cysts after pathological fractures were published. Most authors will not accept the possibility of a “healing fracture” in bone cysts because of missing documentation. In our clinic we could observe spontaneous healing of a juvenile bone cyst of the tibia after a pathological fracture in a ten-year old boy. Therefore healing of bone cysts after fracture is proven. On the other hand healing of bone cysts following conservative treatment after a fracture is not sure. Conservative treatment depends on the localization and type of the fracture. We recommend nonoperative treatment of first pathological fractures in small-sized bone cysts. This kind of treatment can be especially advised for young patients up to the tenth year because there are only few complications in fracture healing and a relatively high recurrence rate following operative treatment. In case of a refracture there are better conditions for fracture healing after surgery.
    Notes: Zusammenfassung Nach pathologischer Fraktur juveniler Knochenzysten (JKZ) wurde in der Literatur über einzelne Fälle von Spontanheilungen der Zysten im Rahmen der Frakturheilung berichtet. Vollständig dokumentierte Fälle liegen jedoch nicht vor, so daß die Möglichkeit einer sog. „heilenden Fraktur“ von den meisten Autoren nicht akzeptiert oder sogar prinzipiell ausgeschlossen wird. In unserer Klinik wurde eine Spontanheilung einer juvenilen Knochenzyste der Tibia nach pathologischer Unterschenkelfraktur bei einem 10 jährigen Jungen beobachtet. Eine Spontanheilung der JKZ im Rahmen der Frakturheilung ist also sicher grundsätzlich möglich. Eine zuverlässige Ausheilung der Zyste kann allerdings auf konservativem Wege nicht erreicht werden, da die osteolytische Potenz erhalten bleibt. Voraussetzung für ein konservatives Vorgehen ist eine geeignete Frakturlokalistation und -form. Unseres Erachtens ist die konservative Behandlung bei einer erstmaligen Spontanfraktur kleinerer Zysten indiziert. Insbesondere gilt dies für junge Patienten bis zum 10. Lebensjahr, aufgrund des günstigen Frakturheilungspotentials bei gleichzeitig bestehendem hohen Zystenrezidivrisiko trotz operativer Therapie. Im Falle der Refraktur ergeben sich für den dann notwendigen Eingriff evtl. günstigere Voraussetzungen aufgrund der Alterszunahme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050512
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  • 18
    Electronic Resource
    Electronic Resource
    Bedeutung von Begleitverletzungen bei Malleolarfrakturen (1999)
    Springer
    Der Unfallchirurg 102 (1999), S. 949-954 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter ; Sprunggelenk • Begleitverletzungen •¶Fraktur • Prognose • Knorpelschaden ; Key words ; Ankle • Injury • Fracture • Outcome •¶Cartilaginous lesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The objective of this prospective study was to determine clinical and radiological results 2 years after ankle fractures and to compare them with preoperative arthroscopic findings. Of 135 consecutive patients undergoing osteosynthetic treatment, 128 (type A, 2; type B, 97; type C, 29) were reviewed 2 years later. The Kitaokascore for functional and clinical rating and the Kannusscore for radiological rating were used. Initial cartilaginous lesions localized on the medial malleolus led to poor clinical ratings (P 〈 0.01) and cartilaginous lesions of the pilon tibiale and talus caused poor radiological results (P 〈 0.032 and P 〈 0.046). After rupture of the deltoid ligament, more pain was observed (P 〈 0.038). Rupture of the syndesmosis, however, did not affect the outcome. Clinical outcome was poor among the 30- to 65-year-old patients. The clinical and radiological outcome of women was poorer (P 〈 0.018 and P 〈 0.046) than for men. The older the patients, the more radiological signs of arthritis were found. The outcome of ankle fracture seems to correlate significantly with the nature, dimension and localization of fracture-associated cartilaginous and ligament lesions. Age and sex also seem to play a significant role in the outcome.
    Notes: Zusammenfassung Die Ziele dieser prospektiven Studie war es, die klinischen und radiologischen Resultate 2 Jahre nach Malleolarfraktur zu bestimmen und diese mit den initialen, arthroskopisch erhobenen Begleitverletzungen nach dem Unfall zu vergleichen. Von 135 konsekutiven Patienten (135 Füsse), die vor der osteosynthetischen Versorgung einer Malleolarfraktur arthroskopisch untersucht wurden, konnten 128 Patienten (Typ A, 2; Typ B, 97; und Typ C, 29) nach durchschnittlich 2 Jahren nachkontrolliert werden. Dabei wurden der Kitaoka-Score (Klinik, Funktion) und der Kannus-Score (Röntgen) verwendet. Initiale Knorpelschäden am medialen Malleolus führten zu einem schlechteren klinischen Resultat (P 〈 0.010), wohingegen Knorpelschäden am Pilon tibiale und Talus ein schlechteres radiologisches Resultat (P 〈 0.032 bzw. P 〈 0.046) zeigten. Nach Ruptur des Lig. deltoideum waren assoziierte Schmerzen gehäuft (P 〈 0.038). Eine Syndesmosenruptur beeinflusste das Resultat nicht. Generell war das klinische Resultat bei den 30- bis 65 jährigen Patienten am schlechtesten und bei Frauen klinisch und radiologisch schlechter als bei Männern (P 〈 0.018 bzw. P 〈 0.046). Die radiologischen Veränderungen nahmen mit dem Alter zu. Das Resultat nach Malleolarfrakturen scheint demnach entscheidend von der Art, Ausmass und Lokalisation der Begleitverletzungen des Knorpels und der Bänder abzuhängen. Daneben könnten Alter und Geschlecht des Patienten präjudizierende Faktoren des Endergebnisses sein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050509
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  • 19
    Electronic Resource
    Electronic Resource
    Bakterielle Koxitis durch Salmonella enteritidis (1999)
    Springer
    Der Unfallchirurg 102 (1999), S. 967-971 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter ; Bakterielle Arthritis • Salmonella enteritidis • Hüftgelenk • Pathologische Diagnostik • Therapie ; Key words ; Bacterial arthritis • Salmonella enteritidis • Hip joint • Pathologic diagnosis • Therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Secondary haematogenous joint involvement is seen in less than 1 % of patients with Salmonella infections. These atypical infections are frequently encouraged by pre-existing local or systemic disease. We present a case of a patient with known alcohol abuse who developed a septic infection of her right hip requiring resection of the femoral head. Histologic analysis showed signs of pre-existing osteonecrosis probably induced by alcohol intake. Cartilage and bone were invaded and destructed by an aggressive granulation tissue. Initially, a biopsy evaluated without knowledge of the positive bacteriological result had been interpreted as indicative of a tumour. The onset, clinical course, diagnosis and therapy of joint involvement by Salmonella are discussed with regard to our case and the relevant literature. This case illustrates the necessity for clinicians to share all their information about the patient with the pathologist.
    Notes: Zusammenfassung Sekundäre hämatogene Gelenkinfektionen werden bei weniger als 1 % aller systemischen Salmonellosen beobachtet. Lokale Gewebeschädigungen oder systemische Grunderkrankungen begünstigen das Zustandekommen dieser atypischen Infektionen. Wir stellen den Fall einer alkoholabhängigen Patientin dar, bei welcher eine Salmonellenkoxitis auf dem Boden einer ischämischen Knochennekrose des Hüftkopfes entstand. Die weit fortgeschrittene Zerstörung des Gelenks erforderte eine Resektionsarthroplastik. Histologisch fand sich eine destruierende Invasion von Knorpel und spongiösem Knochen durch zellreiches Entzündungsgewebe. In Unkenntnis des bakteriologischen Befundes war zunächst der Verdacht auf eine neoplastische Veränderung geäußert worden. Entstehung, Verlauf, Diagnostik und Therapie der Salmonellenarthritis werden anhand dieses Falles und der Literatur diskutiert. Die erfolgreiche Befundung einer Knochenbiopsie ist auf eine gute Kommunikation zwischen Kliniker und Pathologe angewiesen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050511
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  • 20
    Electronic Resource
    Electronic Resource
    Operative Behandlung von Verletzungen des thorakolumbalen Übergangs (1999)
    Springer
    Der Unfallchirurg 102 (1999), S. 924-935 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter ; Arbeitsgemeinschaft „Wirbelsäule“ der DGU • Thorakolumbale Wirbelsäule • Wirbelsäulenverletzung • Operative Behandlung • Epidemiologie • Magerl-Klassifikation • Querschnittlähmung • Frankel-/ASIA-Score •¶Hannover Wirbelsäulenscore ; Key words ; Working group “spine“ of the German Society of Trauma Surgery • Thoracolumbar spine • Spinal fracture • Injuries of the spine • Operative treatment • Epidemiology • Classification of thoracolumbar spinal injuries by Magerl • Paraplegia • Frankel/ASIA grading system • Hannover Spine Score
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The authors report on a prospective multicenter study with regard to the operative treatment of fractures and dislocations of the thoracolumbar spine. 18 traumatologic centers in Germany and Austria, forming the working group “spine“ of the German Society of Trauma Surgery, are participating in this continuing study. Between September 1994 and December 1996 682 patients (64 % male) with an average age of 391/2 (7–83) years were entered. The entry criteria included all patients with acute and operatively treated (within 3 weeks after trauma) fractures and dislocations of the thoracolumbar spine (Th 10-L 2). Part 1 of this publication outlines the protocol and epidemiologic data. The incidence of fractures and dislocations of the thoracolumbar spine and associated injuries were recorded according to a standardized protocol, as well as the different operative methods and complications, duration of hospital stay, rehabilitation and incapacity. The analysis of the clinical social and radiological course was a second focus. The most frequent mechanism of injury was a fall (50 %) or traffic accident (22 %). Most of the fractures occured at the L 1 level (49 %). All injuries were classified according to the ASIF (AO) classification. 65 % sustained an A-type fracture (compression fracture). Associated injuries were observed in 35 % and 6 % were polytraumatized. Extremities and thorax were most frequently affected. Younger age and traffic accidents lead more often to C-type fracture (fracture dislocation) and polytrauma. An increased number of multisegmental or multilevel lesions were observed in polytraumatized patients. There were 16 % with incomplete paraplegia (Frankel/ASIA B–D) and 5 % with complete paraplegia (Frankel/ASIA A). The rate of patients with initial neurologic deficits significantly increased with the severity of spinal injury according to the Magerl classification. Until discharge a neurologic improvement (at least 1 Frankel/ASIA grade) was observed in 32 % of the partially paralyzed (Frankel/ASIA B–D) and in 12 % of the patients with complete paraplegia (Frankel/ASIA A). A neurologic deterioration occured in 3 patients (0.4 %). As a base for further follow-up and late results the individual starting point was determined by collecting relevant data of the patients' history: 277 (40.6 %) patients suffered from simultaneous diseases, one half was spine related. At the time of injury 559 (82.0 %) patients were employed; 429 (62.9 %) doing manual work. 369 (54.1 %) patients stated sportive activities before the injury and 561 (82.3 %) designated their “back function“ as normal. For the time before injury the patients scored an average of 93.4 points in the Hannover Spine Score (0–100 points concerning complaints and function of the back/spine).
    Notes: Zusammenfassung Die Autoren berichten über eine prospektive, multizentrische Studie zur operativen Behandlung frischer Verletzungen des thorakolumbalen Übergangs der Wirbelsäule. An der noch nicht abgeschlossenen Studie sind insgesamt 18 unfallchirurgische Kliniken in Deutschland und Österreich beteiligt; sie bilden die Arbeitsgemeinschaft „Wirbelsäule“ der Deutschen Gesellschaft für Unfallchirurgie. Von September 1994 bis Dezember 1996 wurden 682 Patienten (64 % männlich) mit einem Durchschnittsalter von 391/2 (7–83) Jahren erfaßt. Die Eingangkriterien schlossen alle Patienten mit frischer und innerhalb von 3 Wochen operierter thorakolumbaler Verletzung (Th 10-L 2) ein. Im Teil 1 des Berichts schildern wir den Aufbau der Studie und epidemiologische Daten. Häufigkeit und Art von Wirbelsäulen- und Begleitverletzungen wurden ebenso einheitlich erfaßt wie Angaben zu den verschiedenen operativen Behandlungskonzepten und Komplikationen, der Dauer der Behandlung, Rehabilitation und Arbeitsunfähigkeit. Die Analyse des klinischen, sozialen und röntgenologischen Verlaufs stellte einen weiteren Schwerpunkt dar. Häufigste Unfallursachen waren Stürze aus der Höhe (50 %) und Verkehrsunfälle (22 %). Der erste Lendenwirbelkörper war mit Abstand am häufigsten betroffen (49 %). Alle Verletzungen wurden nach der AO-Einteilung klassifiziert; 65 % aller Patienten erlitten Kompressionsverletzungen (Typ A). Bei 59 % lag eine isolierte Wirbelsäulenverletzung vor, die übrigen wiesen Begleitverletzungen auf und 6 % waren polytraumatisiert. Begleitverletzungen betrafen am häufigsten Extremitäten und Thorax. Jüngere Patienten und Verkehrsunfallopfer erlitten häufiger eine Rotationsverletzung (Typ C) und waren häufiger polytraumatisiert. Mehrsegment- oder Mehretagenläsionen waren häufiger bei Polytraumatisierten. Eine inkomplette Querschnittläsion (Frankel/ASIA B–D) wiesen 16 %, eine komplette (Frankel/ASIA A) 5 % auf. Der Anteil neurologisch beeinträchtigter Patienten nahm mit der Verletzungsschwere signifikant zu. Bei 32 % der Patienten mit inkomplettter Lähmung besserte sich der neurologische Befund bis zur Entlassung um mindestens 1 Stufe nach dem Frankel-/ASIA-Schema, bei 12 % nach Paraplegie. Zu einer Verschlechterung um mindestens 1 Stufe kam es bei 3 Patienten (0,4 %). Als Grundlage differenzierter Nachuntersuchungsergebnisse wurden Angaben zur individuellen Situation vor dem Unfall erfaßt: 277 (40,6 %) Patienten wiesen Vorerkrankungen auf, etwa die Hälfte davon solche der Wirbelsäule. 559 (82,0 %) Patienten waren zum Zeitpunkt des Unfalls berufstätig; 429 (62,9 %) gingen einer körperlichen Arbeit nach. 369 (54,1 %) Patienten gaben sportliche Freizeitaktivitäten an und 561 (82,3 %) bezeichneten ihre Rückenbeweglichkeit als normal. Im Hannover Wirbelsäulen-Score (0–100 Punkte zu Beschwerden und Funktion) erzielten die Patienten für die Zeit vor dem Unfall im Mittel 93,4 Punkte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050507
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  • 21
    Electronic Resource
    Electronic Resource
    Immunocytochemical investigation of catalase and peroxisomal lipid β-oxidation enzymes in human hepatocellular tumors and liver cirrhosis (1999)
    Springer
    Virchows Archiv 435 (1999), S. 486-495 
    Details
    ISSN: 1432-2307
    Keywords: Key words Peroxisomes ; Hepatocellular tumors ; Immunocytochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A significant reduction of catalase activity, a peroxisomal marker enzyme, occurs in human hepatic neoplasias, but no information is available on other peroxisomal proteins. We have studied by means of immunohistochemistry four specific proteins of peroxisomes (catalase and three enzymes of lipid β-oxidation) in human hepatocellular tumors of various differentiation grades from adenoma to anaplastic carcinoma. In all tumors, except the adenomas, the tumor cells contained fewer peroxisomes than extrafocal hepatocytes and the reduction of antigenic sites in the tumor types generally correlated with the degree of tumor dedifferentiation as assessed by classical histopathological criteria. Two poorly differentiated tumors had no detectable peroxisomes at all. There were no major differences in the intensities of the immunocytochemical staining for all four studied peroxisomal antigens in different tumors, suggesting that the neoplastic transformation affects the biogenesis of the entire organelle and not merely the individual peroxisomal enzyme proteins. Some tumors exhibited a distinct peripheral distribution of peroxisomes. In cases with associated liver cirrhosis, the hepatocytes in the adjacent liver showed marked peroxisome proliferation, forming large perinuclear aggregates, occupying occasionally the entire cytoplasm. Taken together, our observations indicate that peroxisomes are significantly altered in both hepatocellular tumors and liver cirrhosis and, thus, could be responsible for some of the metabolic derangements observed in those disease processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004280050432
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  • 22
    Electronic Resource
    Electronic Resource
    p21 Expression in colorectal carcinomas: a study on 103 cases with analysis of p53 gene mutation/expression and clinic-pathological correlations (1999)
    Springer
    Virchows Archiv 435 (1999), S. 559-565 
    Details
    ISSN: 1432-2307
    Keywords: Key words p21 ; p53 ; Colon ; Immunohistochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The WAF1/CIP1 gene product, p21, an inhibitor of cyclin-dependent kinases, is a critical downstream effector in the p53 pathway. The expression of p21 in human neoplasms is heterogeneous, and may be related to p53 functional status. We evaluated p21 immunoreactivity in 103 colorectal carcinomas (CC) in relation to the p53 gene and protein alterations and clinico-pathologic parameters. High p21 expression (more than 10% reactive cells) was seen in 39% of cases. p21 staining was heterogeneous and often detected in clusters of tumour cells; in some tumours p21 staining was more pronounced in superficial areas. No relation was seen between p21 immunoreactivity and site of the tumours (right vs left), TNM stage and grade. p21 expression was related to p53 status as evaluated with IHC or with SSCP analyses, low p21 expression usually being associated with p53 protein overexpression (P=0.048) and p53 gene alteration (P=0.005). The strongest associations were seen when the combined p53/p21 immunophenotype was compared with p53 gene alterations (P=0.0002). These data support the hypothesis that p21 expression in CC is mainly related to p53 functional status, suggesting that p21 expression could be an interesting adjunct in the evaluation of the functional status of the p53 pathway in CC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004280050441
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  • 23
    Electronic Resource
    Electronic Resource
    Alpha-1-microglobulin: inhibitory effect on calcium oxalate crystallization in vitro and decreased urinary concentration in calcium oxalate stone formers (1999)
    Springer
    Urological research 27 (1999), S. 243-249 
    Details
    ISSN: 1434-0879
    Keywords: Key words Alpha-1-microglobulin ; Calcium oxalate ; Crystallization ; ELISA ; Human ; Urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the past few years, alpha-1-microglobulin (α1m) has been copurified from human urine with bikunin, a potent inhibitor of calcium oxalate (CaOx) crystallization in vitro. In this study, we have purified α1m without bikunin contamination and investigated its possible role in CaOx crystallization by in vitro and in vivo studies. Alpha-1m was purified with an anti-α1m antibodies CNBr-activated sepharose column. Two molecular species of α1m of respectively 30 and 60 kDa were purified. For each protein, two blots of 30 and 60 kDa cross-reacted with anti-α1m antibodies, suggesting that these two forms were derived one from the other. Both protein species inhibited CaOx crystallization in a dose-dependent manner in two in vitro tests. In the first test, the presence of α1m of 30 kDa (8 μg/ml) in a medium containing 0.76 mM CaCl2 (with 45Ca) and 0.76 mM Ox(NH4)2 inhibited CaOx crystallization by 38% as estimated by supernatant radioactivity after 1 h of agitation. In the second test, CaOx kinetics were examined for 3 to 10 min in a turbidimetric model at 620 nm. The presence of α1m of 30 kDa in a medium containing 4 mM CaCl2 and 0.5 mM Na2Ox inhibited CaOx crystallization by 41.5%, as estimated by the slope modification of turbidimetric curve. Alpha-1m can be considered as another inhibitor of urinary CaOx crystal formation, as shown by the present in vitro studies. Using an ELISA assay, we found that urinary α1m concentration was significantly lower in 31 CaOx stone formers than in 18 healthy subjects (2.95 ± 0.29 vs 5.34 ± 1.08 mg/l respectively, P = 0.01). The decreased concentration of α1m in CaOx stone formers could be responsible in these patients, at least in part, for an increased risk of CaOx crystalluria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002400050117
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  • 24
    Electronic Resource
    Electronic Resource
    Ersatz des vorderen Kreuzbands in der TransFix®-Technik (1999)
    Springer
    Arthroskopie 12 (1999), S. 305-312 
    Details
    ISSN: 1434-3924
    Keywords: Schlüsselwörter ; Kreuzbandersatzoperation ; Hamstring-Sehnen ; Femorale Fixation ; Tibiale Fixation ; Key words ; Anterior cruciate ligament reconstruction ; Hamstrings ; Femoral fixation ; Tibial fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: In recent years ACL reconsruction with the midpatellar tendon has been being called into question more and more because of high morbidity at the harvest site and problems with fixation near the joint. The”wiper effect” or “bungee-effect” may be mentioned as an example. In this paper, ACL reconstruction using the hamstrings is presented, which, in contrast to fixation with the Endobutton, has a very high pull out strength and also tibial fixation near the joint with a biodegradable interference screw. This surgical method has been carefully developed and is technically sophisticated. The technique can be used mainly in younger women with small patellae, athletically inactive persons with a high level of instability, all patients with parapatellar problems or pain, and patients whose occupation involves kneeling. The short-term results are excellent; long-term results with this new method are not yet available. This method should be seen as an alternative to ACL reconstruction with the midpatellar tendon and, in our view, the security of fixation is at least as good as with the Endobutton.
    Notes: In den letzten Jahren wird die Kreuzbandersatzoperation mit dem mittleren Patellarsehnendrittel zunehmend mehr in Frage gestellt. Gründe sind die hohe Transplantatentnahmemorbidität sowie Probleme bei der gelenknahen Fixation. Der Scheibenwischereffekt, der Bungee-Effekt u. a. seien hierfür stellvertretend genannt. Im folgenden wird daher eine Kreuzbandersatzoperationstechnik unter Verwendung der Hamstring-Sehnen vorgestellt, die im Gegensatz zur Fixation über den Endobutton ® eine sehr ausreißfeste femorale Fixation sowie eine ebenfalls gelenknahe tibiale Fixation über eine biodegradierbare Interferenzschraube beinhaltet. Die Operationsmethode ist durchdacht und technisch ausgereift. Indikationen stellen vorwiegend jüngere Frauen mit kleiner Kniescheibe, sportlich wenig aktive Menschen mit hochgradiger Instabilität sowie alle Patienten mit parapatellaren Problemen oder Schmerzen, des weiteren Patienten mit kniender Tätigkeit dar. Die Kurzzeitresultate sind hervorragend, Langzeitergebnisse stehen bei dieser jungen Methode noch aus. Die Methode sollte als Alternativvariante zur Kreuzbandersatzoperation mit dem mittleren freien Patellarsehnendrittel gesehen werden und ist in ihrer Fixationssicherheit aus unserer Sicht dem Endobutton mindestens gleichwertig.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001420050107
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  • 25
    Electronic Resource
    Electronic Resource
    All-Press-FIT, eine neue Operationsmethode zum vorderen Kreuzbandersatz mit gleichzeitiger femoraler und tibialer Press-Fit-Verankerung (1999)
    Springer
    Arthroskopie 12 (1999), S. 299-304 
    Details
    ISSN: 1434-3924
    Keywords: Schlüsselwörter ; Vorderes Kreuzband ; Rekonstruktion ; Patella-bone-tendon-bone ; Press-fit-Fixation ; All-Press-fit ; Doppelblockfixierung ; Key words ; ACL Reconstruction ; Bone-Patellar-tendon-bone autograft ; Press-fit ; Implant free fixation ; All-Press-Fit-fixation ; Doubleblock fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: In the treatment of anterior cruciate ligament reconstruction, bone-patellar-tendon-bone allograft has been developed to a standard. Fixation of the graft with interference screws in the femur and/or with staple in the tibia are usual. ALL-PRESS-FIT fixation makes an implant-free acl-reconstruction possible. The bone-patellar-tendon-bone allograft is harvested with oversized bone blocks. The “Bone-Compactor” is used for modelling the oversized boneblocks for press-fit-fixation in femur und tibia. Implantation can be managed in either an arthroscopic or open procedure. The proximal boneblock is implanted with a sagittal alignment of the tendon. While rotating the distal block 90° to medial, a recontruction of anteromedial und posterolateral fascicle is possible. Tension can be controlled after step-by-step fixation proximal and distally with a distalisation of the tibial block at the end. The prominent tibial block will be pressed in on corticalis-niveau with the “Reconcillation-Hit”. A femoral or tibial “Doubleblock-Fixation” allows a better anatomical reconstruction. A third bone block, harvested from the tibial channel, fixed on the distal ligament, is used to fill up the tibial channel with bone to the tibial plateau. The “tibial doubleblock-fixation” allows a better biomechanical bone fixation of the ligament. Alternatively, a patellar-bone-tendon-bone allograft can be used with a high tibial press-fit fixation with a ligament outlet directly onto the tibia plateau. The proximal boneblock is implanted deep in the whole femur whole and fixed with the third bone block harvested from the tibial channel.
    Notes: Bei der operativen Versorgung der vorderen Kreuzbandruptur hat sich die Verwendung des mittleren Drittels der Patellarsehne als Standard etabliert. Die Knochenblöcke aus Patella und Tibiakopf werden üblicherweise mit Interferenzschrauben oder Staple fixiert. Mit der All-Press-FIT-Verankerung ist eine fremdimplantatfreie femorale und tibiale Verankerung möglich. Der mittlere Sehnenanteil des Lig. patellae wird mit Knochenblöcken aus der distalen Patella und dem Tibiakopf gewonnen. Mit dem Knochenkompaktor, der als Zurichtungsinstrument und Schablone dient, werden die Knochenblöcke in notwendiger Übergröße so zugerichtet, daß sie später femoral und tibial ohne zusätzliche Hilfsmittel press fit verankert werden können. Die Implantation ist sowohl arthroskopisch als auch offen möglich. Der obere Knochenblock wird so eingebracht, daß ein vorderes und hinteres Bündel entsteht. Durch Rotieren des unteren Knochenblocks entsteht ein anteromediales und posterolaterales Bündel. Zur nachträglichen Korrektur der Bandspannung kann der tibiale Knochenblock nach distal ausgetrieben werden. Der Knochenblock wird dann mit dem „Versöhnungsschlag“ auf Kortikalisniveau versenkt. Die femorale oder tibiale „Doppelblockfixierung“ ermöglicht eine anatomiegerechte Rekonstruktion. Ein aus dem Tibiakopf entnommener dritter kortikospongiöser Knochenblock armiert den Ligamentanteil im Tibiakanal für eine bessere knöcherne Führung des Bands. Die so erzielte tibiale Doppelblockfixierung ermöglicht eine anatomiegerechte sagittale Ausrichtung des Ligaments durch eine langstreckige knöcherne Stabilisierung im Tibiaplateau. Alternativ wird der tibiale Knochenblock auf Höhe des Tibiaplateau press fit festgesetzt. Der patellare Knochenblock wird tief in dem femoralen Kanal eingesetzt. Das Ligament wird mit dem Eintreiben des aus dem Tibiabohrkanal gewonnenen Knochenblocks angespannt und femoral gelenknah verankert. Es entsteht die femorale Doppelblockfixierung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001420050106
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  • 26
    Electronic Resource
    Electronic Resource
    Versican in human fetal skin development (1999)
    Springer
    Anatomy and embryology 199 (1999), S. 45-56 
    Details
    ISSN: 1432-0568
    Keywords: Key words Skin ; Proteoglycan ; Development ; Human ; Fetal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The extracellular matrix of human fetal skin differs substantially from that of adult skin. Fetal skin contains sparse amounts of fibrillar collagen enmeshed in a highly hydrated amorphous matrix composed of hyaluronan and sulfated proteoglycans. Both fetal and adult skin contain two major interstitial proteoglycans that are extracted by chaotrophic agents and detergents. These are the large chondroitin sulfate proteoglycan versican and the small dermatan sulfate proteoglycan decorin. For this study, proteoglycans extracted from fetal and adult skin were compared on Western blots to determine the relative amounts of versican. Decorin present in the same samples provided an internal standard for these studies. Fetal skin differed from adult skin in that it contained a significantly higher proportion of versican than did adult skin. Immunohistochemical studies compared early-fetal with mid-fetal skin and found that versican was a significant component of the interstitial extracellular matrix at both of these stages of skin development. However, by the mid-fetal period, interstitial versican became restricted to the upper half of the dermis, although versican also continued to be highly expressed around hair follicles, glands, and vasculature in the lower half of the dermis. Fetal skin extracts differed from an adult skin extract by the presence of a 66-kDa protein immunologically related to versican and by the absence of a 17-kDa core protein of a proteoglycan related to decorin. Both of these molecular species may represent degradation products of their respective proteoglycans. Monoclonal antibodies which detect epitopes in native chondroitin sulfate glycosaminoglycan chains recognized versican extracted from fetal skin. However, the tissue distribution of these antigens did not entirely conform to that for versican core protein, suggesting that versican in different regions of the skin may be substituted with glycosaminoglycan chains with different microchemistries. The results of these studies indicate that human fetal skin is structurally different from adult skin in terms of both the distribution and the composition of the large, aggregating chondroitin sulfate proteoglycan versican.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050208
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  • 27
    Electronic Resource
    Electronic Resource
    The N-methyl-d-aspartate receptor channel blocker amantadine does not cause histopathological alterations in human brain tissue (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 85-90 
    Details
    ISSN: 1432-0533
    Keywords: Key words Amantadine ; Human ; N-methyl-d-aspartate ; Phencyclidine ; Postmortem brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Low doses of N-methyl-d-aspartate (NMDA)-type glutamate receptor antagonists induce morphological alterations in neurons of the cingulate gyrus and retrosplenial cortex of the rat. Neuronal cell death may result at higher doses. These effects are a major concern with regard to the introduction of new NMDA receptor antagonists into clinical trials. Amantadine is an uncompetitive NMDA receptor antagonist, which has been in clinical use for many years. In the present study we have looked for possible morphological alterations like necrosis in postmortem human brain tissue of patients previously treated with amantadine. Formalin-fixed tissue samples were taken from the hippocampus, cingulate gyrus, and retrosplenial cortex of 8 patients on previous amantadine medication and of 11 controls. Histopathological examination of sections was performed blind. All brains except one revealed either nonspecific age-related or cerebrovascular changes or other neurodegenerative disorders including Alzheimer’s, Parkinson’s or Lewy body disease. In conclusion, histopathological examination of the hippocampus, retrosplenial cortex, and cingulate gyrus of human brain did not reveal changes suggested to be specific for previous amantadine treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010051054
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  • 28
    Electronic Resource
    Electronic Resource
    Development of Purkinje cells in humans: an immunohistochemical study using a monoclonal antibody against the inositol 1, 4, 5-triphosphate type 1 receptor (IP3R1) (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 226-232 
    Details
    ISSN: 1432-0533
    Keywords: Key words Purkinje cell ; Cerebellum ; Development ; Inositol 1 ; 4 ; 5-triphosphate type 1 receptor ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immunohistochemical analyses were carried out on the Purkinje cells from 21 autopsied fetal and early postnatal normal cerebella using a monoclonal antibody against the inositol 1, 4, 5-triphosphate type 1 receptor (IP3R1) as a cytochemical marker of Purkinje cells. In normal adult cerebella used as positive controls, the cell bodies, axons, and dendrites, including spiny branchlets of the Purkinje cells, were specifically stained by the antibody. In the fetal cerebella examined, the IP3R1 immunoreactivity was first detected in the soma of multilayered cells just beneath the molecular layer at 16 weeks of gestation. The IP3R1 immunoreactivity gradually increased in area of positive staining from soma to dendrites and spiny branchlets, and the dendritic outgrowth rapidly progressed during 6 months after birth. The Purkinje cell maturation was more advanced in the vermis than in the hemisphere, more in the posterior lobe than in the anterior lobe, and more at the bottom of the folia than at the top. Partial absence of the Purkinje cells in the cerebellar cortex was observed in three cases. Heterotopias including Purkinje cells were often noted in the cerebellar white matter in five cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010051073
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  • 29
    Electronic Resource
    Electronic Resource
    The effects of NSAID on the matrix of human articular cartilages (1999)
    Springer
    Zeitschrift für Rheumatologie 58 (1999), S. 125-129 
    Details
    ISSN: 0340-1855
    Keywords: Key words NSAIDs ; cartilage turnover ; GAG synthesis ; IL-1 inhibition ; Schlüsselwörter ; NSAR-Knorpelumsatz ; GAG-Synthese ; IL-1-Hemmung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die vorliegende Arbeit präsentiert während einer 12-Jahres-Periode mit einer Standard-in-vitro-Methode gesammelte Daten über Synthese und Umsatz des Gelenkknorpels von 650 arthritischen und 180 nicht-arthritischen (N) Individuen. Beim Vergleich der relativen metabolischen (synthetischen/reparativen Aktivität) dieser menschlichen Gelenkknorpel läßt sich zeigen, daß bei der Arthrose (OA) und der rheumatoiden Arthritis (RA) die Knorpelsynthese um etwa 50% im Vergleich zu N-Knorpeln reduziert ist. Bezüglich des Matrixumsatzes aber gab es keinen signifikanten Unterschied zwischen nicht-arthritischem und arthrotischem Knorpel, während dieser beim RA-Knorpel – vereinbar mit der Aktivität von Entzündungszellen und aus dem Pannus freigesetzten Enzymen – deutlich erhöht war. Die Wirkung von 13 NSAR auf die Glukoseaminoglykansynthese wurde verglichen. Drei dieser NSAR wurden auch auf ihre Wirkung auf die Knorpel-Kollagen-Synthese untersucht. Die Ergebnisse dieser Studie und Literaturangaben führen zu dem Vorschlag die NSAR bezüglich ihrer in-vitro-Wirkung auf die extrazelluläre Matrix des arthritischen Gelenkknorpels in drei Kategorien zu teilen: 1. Substanzen wie Aceclofenac, Tenidap und Tolmetin, die die Matrixsynthese stimulieren können 2. Substanzen wir Piroxicam, Tiaprofensäure und Aspirin ohne signifikanten Effekt auf die Matrixsynthese und 3. Substanzen wie Naproxen, Ibuprofen, Indometacin, Nimezulide, die die Matrixsynthese signifikant hemmen. Es ist anzunehmen, daß die stimulierende Wirkung der NSAR der Gruppe 1 auf die Hemmung des lokal produzierten IL-1 und die nachfolgend zunehmende Aktivität von Wachstumsfaktoren zurückzuführen ist. Andere NSAR können Synthese oder Freisetzung von IL-1 ebenfalls hemmen, hemmen möglicherweise aber gleichzeitig aufgrund toxischer Effekte die synthetische Aktivität der Chondrozyten. Diese Experimente weisen darauf hin, daß NSAR wie Aceclofenac für die Langzeitbehandlung der Arthritis geeignet sind, vorausgesetzt, die in-vitro Experimente am menschlichen Knorpel lassen sich auf die Situation in-vivo übertragen.
    Notes: Summary The present paper presents data obtained over a 12 year period, on the matrix synthesis and turnover in some 650 arthritic and 180 non-arthritic (N) human cartilages using a standardised in vitro method. When the relative metabolic (synthetic/repair activity) of these human cartilages was compared, it was demonstrated that in osteoarthritis (OA) and rheumatoid arthritis (RA) cartilages synthetic activity was diminished by approximately 50% as compared with N cartilages. However, the turnover rate of matrix was not significantly different between Non-arthritic and OA, but was very substantially increased in RA cartilages compatible with the activity of inflammatory cells and proteolytic enzymes released from pannus. The action of 13 NSAIDs was compared in terms of their effect on cartilage GAG synthesis. 3 of these NSAIDs were also studied in terms of their effect on cartilage collagen synthesis. Consideration of the results in this study and from published material, led to the suggestion that NSAIDs may be divided into 3 categories in respect of their in vitro action on the extracellular matrix of human arthritic cartilages: 1. Those such as Aceclofenac, Tenidap and Tolmetin which can stimulate matrix synthesis 2. Those such as Piroxicam, Tiaprofenic Acid and Aspirin which appear to be without significant effect on matrix synthesis and, 3. Those like Naproxen, Ibuprofen, Indomethacin, Nimezulide which significantly inhibit matrix synthesis. It is suggested that the stimulatory action of group 1 NSAID is due to inhibition of locally produced IL1 and consequent expression of growth factor activity. Other NSAIDs may also inhibit IL1 synthesis or release, but probably do not have a beneficial effect on chondrocyte synthetic activity as they have toxic effects on cartilage metabolism. These experiments led to the suggestion that NSAIDs such as Aceclofenac would be appropriate for long-term treatment of arthritic conditions provided that one is prepared to extrapolate between in vitro experiments on human cartilage and what may be happening in vivo.
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    URL: http://dx.doi.org/10.1007/s003930050161
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    Electronic Resource
    Joint cartilage regeneration by tissue engineering (1999)
    Springer
    Zeitschrift für Rheumatologie 58 (1999), S. 130-135 
    Details
    ISSN: 0340-1855
    Keywords: Key words Cartilage repair ; tissue engineering ; biomaterials ; bone morphogenetic proteins ; Schlüsselwörter ; Knorpeltransplantation ; Tissue Engineering ; Biomaterialien ; Bone Morphogenetic Proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Forschungsgebiet Tissue Engineering verbindet die Bereiche Zellbiologie, Biomaterialforschung und Chirurgie. Wichtigstes Ziel ist ein Gewebe- und Organersatz mit Hilfe gezüchteter Zellen des Patienten. Unsere Arbeit konzentriert sich auf die Therapie schwerer Gelenkknorpeldefekte und die Geweberekonstruktion in der plastischen Chirurgie mit Hilfe in vitro hergestellter Knorpeltransplantate. Dieser praktische Ansatz erfordert zunächst Techniken zur dreidimensionalen Zellverteilung und Einbettung sowie einer temporären mechanischen Stabilisierung. Die Knorpelzüchtung basiert auf einer biokompatiblen Einbettung der Zellen in Agarose, Fibrin, Alginat oder Hyaluronsäure in Verbindung mit einer Gerüststruktur aus resorbierbaren Polymerfaservliesen (PLLA/PGLA). In interagierenden dreidimensionalen Kulturen können unterschiedliche Zellpopulationen wie z.B. BMP-transfizierte Zellen eingesetzt werden. Gezüchtete Gewebe wurden vorgeformt und in Perfusionskammern kultiviert. Anschließend wurden sie subkutan in Nacktmäuse und in Gelenkknorpeldefekte bei Kaninchen implantiert. Die Transplantate zeigen eine knorpeltypische Histologie und Matrixentwicklung. Etwa 20% der Gewebe wurden teilweise resorbiert oder durch fibröses Bindegewebe ersetzt. Die Ergebnisse zeigen, daß die Technologie des Knorpel-Tissue-Engineerings vielversprechend für die plastische Geweberekonstruktion ist. Die Behandlung großflächiger Gelenkknorpeldefekte erfordert jedoch zunächst die Lösung einiger wichtiger Probleme: (a) die Verankerung eines gezüchteten Gewebeersatzes im Gelenk, (b) ein Schutz der Transplantate vor chronischen Entzündungsvorgängen und Degradation, (c) die enorm hohe mechanische Druckbelastbarkeit.
    Notes: Summary The research field of tissue engineering combines cells biology, biomaterial science, and surgery. Major long-term goals are tissue and organ replacement therapies using the patients‘ own cells. Our work is focused on the treatment of severe joint defects and on plastic surgery using in vitro engineered cartilage tissues. The practical approaches in cartilage engineering face problems with three-dimensional cell distribution or cell immobilization raising biocompatibility problems. The tissue engineering of cartilage is based on combining biocompatible cell embedding substances such as fibrin, agarose, alginate, hyaluronic acid and fiber fleece scaffolds of poly α-hydroxy acids (PLLA/PGLA). Different technical approaches were established: a) three-dimensional in vitro cultures of chondrocytes for the development of vital tissue transplants and b) interacting three-dimensional cultures consisting of different cell populations, such as BMP-transfected mesenchymal cells. The preshaped artificial tissue constructs were cultured in perfusion chambers to maintain a stable diffusion of nutrients during the in vitro pre-formation step. Subsequently, pre-formed tissues were implanted into nude mice and into 4mm articular joint defects of rabbits. Transplants were found to produce cartilage typic morphological patterns and matrix. 80% of the transplants remained stable in vivo. However, 20% of the tissues are resorbed or replaced by a fibrous tissue. These results demonstrate that current artificial cartilage transplants are already feasible for plastic reconstruction. The treatment of severe joint defects, however, faces additional problems which are addressed in ongoing studies: (a) the fixation of engineered cartilage in joints, (b) the protection against chronic inflammatory degradation, and (c) the required enormous mechanical stability
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003930050162
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    Electronic Resource
    Long-term application of disease modifying antirheumatic drugs (DMARD). A single-center, observational study of 1681 patients with rheumatoid arthritis (RA) (1999)
    Springer
    Zeitschrift für Rheumatologie 58 (1999), S. 267-276 
    Details
    ISSN: 0340-1855
    Keywords: Key words ; Rheumatoid arthritis ; DMARD therapy ; observation study ; Schlüsselwörter ; Rheumatoide Arthritis ; Basistherapie ; Langzeitverlauf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ziel der Arbeit: Untersuchung der Langzeiteffektivität und Verträglichkeit der Basistherapie mit Methotrexat (MTX), Azathioprin (AZA), intramuskulärem Gold, D-Penicillamin (DPA), Sulfasalazin (SASP) und Cholorochin (CQ) bei rheumatoider Arthritis (RA). Methoden: Zwischen 1979 und 1994 wurden Daten von 1681 Patienten des Rheumazentrums Rostock prospektiv erfaßt. Eine 50%ige Reduktion der Anzahl geschwollener Gelenke war erforderlich, um die Therapie fortzuführen. Zusätzlich wurden in halbjährlichen Abständen ein modifizierter Lansbury-Index, der Bewegungsfunktionstest nach KEITEL sowie akute-Phase-Parameter erfaßt. Nebenwirkungen, die zum Abbruch der Therapie führten, wurden ebenfalls festgehalten. Ergebnisse: Nach einer Beobachtungszeit von mindestents vier Jahren nahmen noch 39,6% bzw. 28,3% der Patienten MTX bzw. AZA ein. 18,2% bekamen Gold, 16,9% DPA. SASP und CQ wurden von 13,5 bzw. 6,6% der Patienten eingenommen. Die Abbruchraten wegen Nebenwirkungen (NW) betrugen für MTX, AZA and SASP 15,9%, 15,3% bzw. 17,7%, während 34,8% CQ wegen NW absetzten (Gold: 27,4%, DPA: 26,9%). Die Mehrzahl der Therapieabbrüche erfolgte bereits im ersten Jahr der Behandlung. Subgruppen seropositiver Patienten bzw. Patienten mit Rheumaknoten oder erosiven Verläufen hatten ein schlechteres Ansprechen auf die Behandlung, unabhängig von der Art des eingesetzten Basistherapeutikums. Schlußfolgerung: MTX war in der Langzeittherapie die effizienteste Substanz, gefolgt von AZA, während CQ die geringste Rate von Langzeitanwendern aufwies. Die Ergebnisse unterstreichen den Stellenwert von Langzeitbeobachtungen unter klinischen Alltagsbedingungen in Ergänzung zu kontrollierten klinischen Studien.
    Notes: Summary Objective: To study the long-term efficacy and safety of methotrexate (MTX), intramuscular gold, azathioprine (AZA), chloroquine (CQ), sulphasalazine (SASP), and D-penicillamine (DPA) in rheumatoid arthritis (RA) patients. Methods: Between 1979 and 1994, clinical data were prospectively gathered in a single center. 1681 patients were followed-up for at least 4 years. A 50% reduction of the swollen joint count was required to continue therapy. In addition, a modified Lansbury index, the Keitel function test, and laboratory parameters were determined every six months. Side effects leading to the discontinuation of treatment were recorded as well. Results: After an observation period of more than four years, 39.6% and 28.3% of patients were taking MTX and AZA, respectively; 18.2% were receiving gold, 16.9% remained on DPA. SASP and CQ were still applied in 13.5% and 6.6%. MTX, AZA and SASP had a drop-out rate due to toxicity of 15.9%, 15.3% and 17.7%, whereas 34.8% had to discontinue CQ (gold: 27.4%, DPA: 26.9%). The majority of dropouts occurred within the first year of treatment. Subgroups of seropositive patients and patients with rheumatoid nodules had a poorer treatment efficacy irrespective of the DMARD. Conclusion: In the long-term application, MTX was the most efficient compound, followed by AZA, whereas CQ had the poorest drug survival. Our results underline the value of long-term observations under the conditions of clinical practice as a supplement to controlled clinical trials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003930050181
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    Electronic Resource
    Ein ungewöhnlicher Fall einer Heberden-Arthrose bei einem jungen Mann (1999)
    Springer
    Zeitschrift für Rheumatologie 58 (1999), S. 95-99 
    Details
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Heberden-Arthrose ; primäre Polyarthrose ; Key words Heberden nodes ; primary osteoarthritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Heberden nodes affect mainly middle-aged women. Inheritance is autosomal dominant in female and autosomal recessive in male patients.  We report the case of a young man who presented already with 12 years of age with pain in the distal finger joints. There were no other clinical or serological signs for other rheumatoid diseases, like psoriatic or rheumatoid arthritis. Radiologic findings were consistent with Heberden‘s osteoarthritis of the finger joints. The joint changes remained clinically and radiologically stable during a time period of more than 15 years. The HLA typing revealed the haplotype HLA A1, B8 and DR4, in accordance with former studies which reported a higher frequency of HLA A1, B8 in families with primary osteoarthritis (early onset osteoarthritis of the large joints in combination with Heberden nodes).
    Notes: Zusammenfassung Die Heberden-Arthrose betrifft hauptsächlich das weibliche Geschlecht im mittleren Alter und wird bei Frauen autosomal dominant und bei Männern autosomal rezessiv vererbt. Wir berichten über den Fall eines männlichen Patienten bei dem bereits im Alter von 12 Jahren eine Heberden-Arthrose der Fingergelenke auftrat. Im Laufe von mehr als 15 Jahren waren diese Veränderungen bei dem Patienten weder klinisch noch radiologisch progredient. Bei der HLA-Typisierung fand sich der Haplotyp HLA A1, B8 und DR4, passend zu anderen Studien, die eine erhöhte Frequenz von HLA A1, B8 bei familiärer Polyarthrose berichten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003930050158
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  • 33
    Electronic Resource
    Electronic Resource
    Gegenwärtige Bedeutung der direkten immunologischen Interventionstherapie durch Antizytokine bei der Rheumatoiden Arthritis (1999)
    Springer
    Zeitschrift für Rheumatologie 58 (1999), S. 251-266 
    Details
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Rheumatoide Arthritis ; TNFα-Antikörper ; TNF-Rezeptor-Fusionsproteine ; IL-1- Rezeptor-Antagonisten ; Key words Rheumatoid arthritis ; TNFα-antibodies ; TNF-receptor-fusion proteins ; IL-1-receptor antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Rheumatoid arthritis (RA) is a chronic inflammatory multisystemic autoimmune disease of unknown origin. RA is clinically characterized by recurrent inflammation of joints, synovialitis, progressive destruction of cartilage or bone tissue and multiorgan involvement. Today all established therapies of RA are still unable to stop or even cure the disease. In most cases these therapies can only reduce progression. Furthermore, these therapies have substantial side effects, which can contribute to the increased mortality of disease. Therefore more effective therapies with fewer side effects are needed. In this context direct immunological intervention strategies increasingly gained interest to inhibit proinflammatory cytokines.  In vivo and in vitro studies as well as experimental therapies documented the important role of the proinflammatory cytokines TNFα and IL-1 in RA. The therapy with TNFα-antibodies or receptor fusion proteins as well as IL-1 receptor antagonists proved to be clinically as well as immunologically highly effective as therapy of RA. The single dose treatment is associated with mild side effects only. In addition, trials using combined TNFα-antibody and methotrexate therapy gave promising results. However, potential severe side effects may occur after repeated therapy cycles or may be discovered after prolonged time of observation only (e.g., allergic reactions, induction of autoantibodies or malignancies). Therefore, at present these therapy options can only be recommended for selected patients, who are included into controlled clinical trials. In addition, repeated courses of therapy seem to lead to reduced therapeutical efficacy (especially in TNFα-antibody therapy). Further controlled studies with cytokine antagonists should especially address these problems and focus in particular on potential inductions of autoantibodies or malignancies as well as on additional long-term side effects.  In contrast to direct inhibition of TNFα or IL-1 several further therapies indirectly influence these cytokines by interference with their synthesis or by alteration of the respective receptors. The importance of these therapeutical options has to be determined as well as the possibility of combination of established therapies with immunological intervention strategies.
    Notes: Zusammenfassung Die Rheumatoide Arthritis (RA) ist eine chronisch-entzündliche, multisystemische Autoimmunerkrankung unklarer Genese. Klinisch ist die Erkrankung durch eine chronisch-rezidivierende Entzündung der Gelenke/Synovia und meist progrediente Gelenkdestruktion durch Knorpel- und Knochenzerstörung charakterisiert. Da bisherige Therapeutika die Erkrankung meist nicht zum Stillstand bringen können und durch ihre Nebenwirkungen teilweise erheblich zur erhöhten Morbidität der Patienten beitragen, gewinnen auf der Suche nach effektiveren Behandlungsformen mit günstigeren Nebenwirkungsprofilen direkte immunologische Interventionstherapien gegen proinflammatorische Zytokine zunehmend an Bedeutung.  In-vitro und tier-experimentelle in-vivo Untersuchungen sowie Therapiestudien belegen die zentrale Bedeutung von TNFα und IL-1 als proinflammatorische Zytokine in der RA. Zahlreiche Therapiestudien zeigen, daß die Behandlung der akuten RA mit TNFα-Antikörpern/-Rezeptorfusionsproteinen oder IL-1-Antagonisten ein klinisch sowie immunologisch sehr effizientes, erfolgreiches Therapiekonzept darstellt, welches bei zeitlich begrenzter Therapiedauer relativ gut vertragen wird. Ferner erscheint eine Kombinationsbehandlung von TNFα-Antikörpern mit Methotrexat ebenfalls erfolgreich zu sein. Langfristig können jedoch schwerwiegenden Nebenwirkungen (schwere Infektionen, Induktion von Autoantikörpern, allergischer Schock, möglicherweise Induktion von Tumoren) sowie abnehmende Therapieeffizienz (Verkürzung des rezidivfreien Intervalles zwischen den Therapiezyklen) unter der Behandlung auftreten, so daß die derzeit verfügbaren TNFα- oder IL-1-Rezeptor-Antagonisten nur unter kontrollierten Studienbedingungen und strenger Indikationsstellung eingesetzt werden sollten. Aufgrund der möglichen schwerwiegenden Langzeit-Nebenwirkungen sollte eine engmaschige Nachbeobachtung der Patienten insbesondere die Nutzen-/Risiko-Relation weiter abklären.  Über die direkte TNFα- oder IL-1-Inhibition hinaus bestehen zahlreiche weitere Möglichkeiten der indirekten immunologischen Interventionstherapie durch Synthese-Hemmung oder Rezeptormodulation von Zytokinen, deren Stellenwert zukünftig noch weiter geklärt werden muß. Auch muß der Nutzen einer Kombination von immunologischer Interventionstherapie mit etablierten Behandlungsoptionen der RA weiter abgeklärt werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003930050180
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    Electronic Resource
    Cultured fibroblasts from chronic diabetic wounds on the lower extremity (non-insulin-dependent diabetes mellitus) show disturbed proliferation (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 93-99 
    Details
    ISSN: 1432-069X
    Keywords: Key words Chronic diabetic wounds ; Human ; fibroblasts ; Wound healing ; Cell culture ; Proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Patients with diabetes mellitus experience impaired wound healing often resulting in chronic foot ulcers. Hospital discharge data indicate that 6–20% of all diabetic individuals hospitalized (mostly with type 2 diabetes) have a lower extremity ulcer. Maintaining glucose levels at acceptable levels (below 10 mmol/l) is considered to be an important part of the clinical treatment, but the exact mechanism by which diabetes delays wound repair is not yet known. We studied this phenomenon by determining the potential of fibroblasts isolated from the ulcer sites of four patients with non-insulin-dependent diabetes mellitus to proliferate in vitro. Controls were fibroblasts isolated from normal skin of the upper leg of five healthy age-matched volunteers and of six non-insulin-dependent diabetes patients. Proliferative capacity was analysed by evaluation of plates after trypsinization and [3H]thymidine incorporation. Fibroblast morphology was studied by light and transmission electron microscopy. Diabetic ulcer fibroblasts, measured by [3H]thymidine incorporation, proliferated significantly more slowly than the nonlesional control fibroblasts (P 〈 0.00047) and age-matched control fibroblasts (P 〈 0.00003). After culturing the fibroblasts for a prolonged period in high-glucose (27.5 mM) and low-glucose (5.5 mM, i.e. physiological) medium, this difference in proliferation rate between diabetic ulcer fibroblasts and nonlesional diabetic fibroblasts remained (P 〈 0.0001 for high-glucose and P 〈 0.0009 for low-glucose on day 7). Fibroblast proliferation in all three groups was slightly lower in high-glucose than in low-glucose medium, although not significantly at any time-point. Light microscopy showed diabetic ulcer fibroblasts to be large and widely spread. Transmission electron microscopy of cultured diabetic ulcer fibroblasts and nonlesional diabetic skin fibroblasts revealed a large dilated endoplasmic reticulum, a lack of microtubular structures and multiple lamellar and vesicular bodies. These results show a diminished proliferative capacity and abnormal morphology of fibroblasts derived from diabetic ulcers of non-insulin-dependent diabetes patients.
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    URL: http://dx.doi.org/10.1007/s004030050389
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  • 35
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    Electronic Resource
    Nickel-induced activation of T cells in individuals with negative patch test to nickel sulphate (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 247-252 
    Details
    ISSN: 1432-069X
    Keywords: Key words T cell activation ; Nickel ; Human ; Interferon-gamma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Contact hypersensitivity to nickel is the most common form of allergic contact dermatitis. To gain insight into the induction of this frequent disease, T cell reactivity towards nickel was investigated in “nonallergic” individuals defined as those with no skin manifestations and a negative patch test towards NiSO4. Surprisingly, we found that nickel induced proliferation of peripheral blood mononuclear cells (PBMC) from 16 of 18 adult individuals tested. This activation was specific, and no stimulation of PBMC was observed using control stimulants at equimolar concentrations. Furthermore, the NiSO4-induced activation required the presence of professional antigen-presenting cells. To describe the functional capacity of the nickel-inducible T cells, cytokine release was investigated in both nickel-allergic and nonallergic individuals. The T cells from both groups released interferon-γ but no interleukin-4 upon stimulation with nickel, suggesting that the functional capacities of these cell populations were similar in nickel-allergic and nonallergic individuals. Thus, at this level, no qualitative differences could be demonstrated between T cells obtained from nickel-allergic and nonallergic individuals.
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    URL: http://dx.doi.org/10.1007/s004030050404
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  • 36
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    Electronic Resource
    Human melanocytes grown in epidermal equivalents transfer their melanin to follicular outer root sheath keratinocytes (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 325-332 
    Details
    ISSN: 1432-069X
    Keywords: Key words ORS cells ; Melanocytes ; Human ; Organotypic cultures ; Melanosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Because outer root sheath (ORS) cells are valuable substitutes for interfollicular epidermal keratinocytes, we wanted to determine whether epidermal equivalents generated from ORS cells and containing cultured melanocytes can serve as an in vitro model for skin pigmentation. In such epidermal equivalents prepared with ORS cells and melanocytes from donors of phototypes II, III and VI, a stratified epithelium resembling normal epidermis developed within 14 days, as documented by histological, ultrastructural (e.g. basement membrane-like structure, keratohyalin granules, keratinosomes) and immunohistochemical (e.g. keratins, integrins, gp80, involucrin, filaggrin) criteria. The melanocytes were localized in the basal layer and accounted for 10% of the total cell number. Heavily pigmented melanocytes from black donors contained regular melanosomes in all stages of maturation, whereas melanocytes derived from white donors contained predominantly melanosomes of stages I and II. Melanosome-laden dendrites were readily detected extending from the heavily pigmented melanocytes, while they were less conspicuous in melanocytes from white donors. The extent of melanosome transfer was independent of the racial origin of the ORS cells. Melanosomes could also be transferred “through racial barriers”. Melanosomes, mainly of stages III and IV, were detected in the ORS cells, being distributed either as single or compound melanosomes, again irrespective of the racial origin of the ORS cells. In conclusion, pigmented epidermal equivalents generated from ORS cells offer practical advantages over other in vitro pigmentation models: (1) the ORS cells are easily and repeatedly available from any donor regardless of age; (2) primary cultures of ORS cells are free of contaminating melanocytes, a bias if using interfollicular epidermal keratinocytes; (3) a high degree of epidermal differentiation is maintained for 3 weeks in fully defined medium, enabling labelling and stimulation experiments to be performed and compounds interfering with melanin pigmentation to be tested.
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    URL: http://dx.doi.org/10.1007/s004030050417
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  • 37
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    Electronic Resource
    Organization of the genes encoding the human proteasome activators PA28α and β (1999)
    Springer
    Immunogenetics 49 (1999), S. 438-445 
    Details
    ISSN: 1432-1211
    Keywords: Key words PA28 ; Proteasome ; Gene structure ; Evolution ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Two proteasome activators PA28α and β, which have been implicated in antigen processing for loading class I MHC molecules, are synthesized in response to Ifn-γ. The human genes encoding these activators (PSME1 and PSME2, respectively) were analyzed by sequencing. Each gene comprised 11 exons, consistent with gene duplication during vertebrate evolution. The intron/exon organization of both genes was highly conserved, the major difference being the absence of the exon encoding the lysine and glutamic acid-rich 'KEKE' motif in PA28β. Two other genes of relevance to the immune system were located close to those for PA28 at 14q11.2 including ISGF3G, a protein involved in transcription after IFNα signalling. These sequences were also characterized.
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    URL: http://dx.doi.org/10.1007/s002510050517
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  • 38
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    Electronic Resource
    Cloning of a new lectin-like receptor expressed on human NK cells (1999)
    Springer
    Immunogenetics 50 (1999), S. 1-7 
    Details
    ISSN: 1432-1211
    Keywords: Key words NK cells ; Human ; Surface molecule ; Lectin superfamily ; NK gene complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Natural killer (NK) cells constitute the third major population of lymphocytes. They possess the inherent capacity to kill various tumor and virally infected cells and mediate the rejection of bone-marrow grafts in lethally irradiated animals. A large family of NK cell receptors belong to the C-type lectin superfamily and are localized to the NK gene complex on Chromosome (Chr) 6 in the mouse and Chr 12 in the human. Genes in the NK gene complex encode type II receptors and examples include the families of NKR-P1, Ly-49, and NKG2 receptors. Examples of other C-type lectin-like NK cell receptors that occur as individual genes are CD94, CD69, and AICL. Here we report the molecular characterization and chromosomal mapping of a human lectin-like transcript (LLT1) expressed on NK, T, and B cells and localized to the NK gene complex within 100 kilobases of CD69. The cDNA encodes a predicted protein of 191 amino acid residues with a transmembrane domain near the N-terminus and an extracellular domain of 132 amino acid residues with similarity to the carbohydrate recognition domain of C-type lectins. The predicted protein of LLT1 shows 59 and 56% similarity to AICL and CD69, respectively. The predicted protein does not contain any intracellular ITIM motifs, suggesting that LLT1 may be involved in mediating activation signals.
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    URL: http://dx.doi.org/10.1007/s002510050679
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  • 39
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    Electronic Resource
    Rezidivierender Schwindel und Synkopen bei einer Patientin mit Eosinophilie (1999)
    Springer
    Der Internist 40 (1999), S. 305-310 
    Details
    ISSN: 1432-1289
    Keywords: Schlüsselwörter ; Hypereosinophilie-Syndrom (HES) ; Schwindel ; Synkope ; KnochenmarktransplantationLiteratur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Starke Schwindelattacken bis hin zu Synkopen waren neben Knochenschmerzen und erhöhter Infektneigung die Erstsymptome bei einer Patientin mit einer unklaren Eosinophilie. Als Ursache wurde ein Hypereosinophilie-Syndrom (HES) festgestellt, nachdem andere Ursachen einer Eosinophilie ausgeschlossen worden waren. Trotz einer Stufentherapie mit Glukokortikoiden und verschiedenen Chemotherapeutika bzw. Immunmodulatoren war die Erkrankung progredient, so daß schließlich eine Knochenmarktransplantation mit einem histokompatiblen Verwandtenspender durchgeführt wurde.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001080050339
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    29jähriger Patient mit Gynäkomastie und kleinen Hoden (1999)
    Springer
    Der Internist 40 (1999), S. 437-441 
    Details
    ISSN: 1432-1289
    Keywords: Schlüsselwörter ; Gynäkomastie ; Hypogonadismus ; Infertilität ; XX-Mann ; SRY-GenLiteratur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Ein 29jähriger Patient stellte sich in unserer Ambulanz mit einer beidseitigen Gynäkomastie und einem beidseits verringertem Hodenvolumen vor. Die Hormonbestimmungen ergaben die Diagnose eines primären Hypogonadismus. Wegen des Verdachts auf ein Klinefelter-Syndrom wurde eine Chromosomenanalyse durchgeführt. Es fand sich eine XX-Konstellation bei fehlendem Y-Chromosom (46,XX-Karyotyp). Männer mit 46,XX-Karyotyp tragen meist eine Translokation des geschlechtsdeterminierenden Gens (SRY-Gen=sex determining region of Y) vom Y- auf ein X-Chromosom, die auch bei unserem Patienten nachgewiesen wurde.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001080050355
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    Mechanism of the silent period following transcranial magnetic stimulation Evidence from epidural recordings (1999)
    Springer
    Experimental brain research 128 (1999), S. 539-542 
    Details
    ISSN: 1432-1106
    Keywords: Key words Silent period ; Transcranial magnetic stimulation ; Motor cortex ; Epidural recordings ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We investigated the nature of the silent period (SP) following transcranial magnetic stimulation by recording corticospinal volleys in a patient with implanted cervical epidural electrodes. Single suprathreshold test stimuli and paired stimuli at interstimulus intervals (ISIs) of 50–200 ms were delivered while the subject maintained a constant background contraction. The silent period duration from a single test stimulus was 357±62 ms. The test motor-evoked potentials were markedly reduced at all the ISIs tested. The I (indirect) waves induced by the test stimulus were largely unchanged at an ISI of 50 ms, suggesting that there was little change in motor cortex excitability. However, the corticospinal volleys, especially the late I waves, were substantially reduced at ISIs of 100 ms, 150 ms, and 200 ms. Our findings suggest that the early part of the SP is mainly due to spinal mechanisms, while the late part of the SP is related to reduced motor cortex excitability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050878
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    Sudden and gradual presentation of distractor objects: differential interference effects (1999)
    Springer
    Experimental brain research 128 (1999), S. 550-556 
    Details
    ISSN: 1432-1106
    Keywords: Key words Selective attention ; Kinematics ; Human ; Visual pathways
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In solving the selection-for-action problem, it is believed that attentional mechanisms enable dominance of target over non-target objects. However, under some conditions, information from non-target objects ”interferes” with the action to a relevant target. We investigated the possibility that this interference may result when the irrelevant object activates a specific subset of visuomotor pathways. Participants reached to grasp three-dimensional stimuli while actively attending to a nearby flanker object. The means by which the flanker was presented was manipulated. This relevant object was illuminated either abruptly or gradually. The parvocellular pathway in early visual processing is equally activated in both conditions. The magnocellular pathway is strongly activated by abrupt presentation and weakly activated with gradual presentation of the flanker object. Kinematics of the reach-to-grasp action to the target showed signs of interference only in the sudden illumination condition. This suggests a dissociation between dorsal and ventral cortical streams in terms of relevance for action. Our data suggests that this effect is not due to early visual-pathway differences, but instead reveals a property of a transient object-based visual attention mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050880
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    Cortical regions contributing to the anterior commissure in man (1999)
    Springer
    Experimental brain research 124 (1999), S. 1-7 
    Details
    ISSN: 1432-1106
    Keywords: Key words Temporal cortex ; Connectivity ; Human ; Interhemispheric transfer ; Talairach coordinates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The human anterior commissure is believed, by extrapolation from data obtained in macaque monkeys, to convey axons from the temporal and orbitofrontal cortex. Reports of interhemispheric transfer and sexual dimorphism related to the anterior commissure, however, make more precise data on the human anterior commissure desirable. We investigated the connectivity of the human anterior commissure in six adults (male and female) that had circumscribed hemispheric lesions in temporal, frontal, parietal or occipital cortices or in infrapallidal white matter using the Nauta for anterogradely degenerating axons. Axons originating in the inferior part of temporal or occipital lobes, occipital convexity and possibly central fissure and prefrontal convexity were found to cross the midsagittal plane in the anterior commissure. The largest contigent of commissural axons originated in the inferior part of the temporal lobe; it displayed a roughly topographic organization, preferentially running through the inferior part of the commissure. The inferior temporal contigent seemed to reach homotopic and heterotopic targets in the opposite hemisphere. Among the latter were the amygdala and possibly the orbitofrontal cortex. The present data suggest that the human anterior commissure conveys axons from much larger territories than expected from work on non-human primates. Similarly to the human and non-human primate corpus callosum, the anterior commissure is roughly topographically organized and participates in heterotopic connectivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050593
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    Development of anticipatory postural adjustments in a bimanual load-lifting task in children (1999)
    Springer
    Experimental brain research 126 (1999), S. 200-204 
    Details
    ISSN: 1432-1106
    Keywords: Key words Motor development ; Anticipatory postural adjustments ; Bimanual coordination ; Children ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Anticipatory postural adjustments (APA) are needed to perform a movement without perturbing posture. We investigated the development of APA in 3- to 4-year-old children during a bimanual load-lifting task. The task required maintaining a stable elbow position despite imposed or voluntary unloading of the forearm. Although children can compensate the consequences of unloading by using APA, their performance did not reach an adults’ level. In addition, children showed high intra-individual variability in the voluntary situation, revealed by the coexistence of both adult-like and immature patterns in kinematic and electromyographic data. In conclusion, the present study reports that APA, associated with a bimanual load-lifting task, are still being set up in 3- to 4-year-old-children. The intra-individual variability should decrease with age and be associated with a progressive mastering of the timing parameters characterizing APA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050729
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    The effects of stochastic galvanic vestibular stimulation on human postural sway (1999)
    Springer
    Experimental brain research 124 (1999), S. 273-280 
    Details
    ISSN: 1432-1106
    Keywords: Key words Vestibular system ; Posture control ; Balance ; Cross-spectral analysis ; Coherency ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Galvanic vestibular stimulation serves to modulate the continuous firing level of the peripheral vestibular afferents. It has been shown that the application of sinusoidally varying, bipolar galvanic currents to the vestibular system can lead to sinusoidally varying postural sway. Our objective was to test the hypothesis that stochastic galvanic vestibular stimulation can lead to coherent stochastic postural sway. Bipolar binaural stochastic galvanic vestibular stimulation was applied to nine healthy young subjects. Three different stochastic vestibular stimulation signals, each with a different frequency content (0–1 Hz, 1–2 Hz, and 0–2 Hz), were used. The stimulation level (range 0.4–1.5 mA, peak to peak) was determined on an individual basis. Twenty 60-s trials were conducted on each subject – 15 stimulation trials (5 trials with each stimulation signal) and 5 control (no stimulation) trials. During the trials, subjects stood in a relaxed, upright position with their head facing forward. Postural sway was evaluated by using a force platform to measure the displacements of the center of pressure (COP) under each subject’s feet. Cross-spectral measures were used to quantify the relationship between the applied stimulus and the resulting COP time series. We found significant coherency between the stochastic vestibular stimulation signal and the resulting mediolateral COP time series in the majority of trials in 8 of the 9 subjects tested. The coherency results for each stimulation signal were reproducible from trial to trial, and the highest degree of coherency was found for the 1- to 2-Hz stochastic vestibular stimulation signal. In general, for the nine subjects tested, we did not find consistent significant coherency between the stochastic vestibular stimulation signals and the anteroposterior COP time series. This work demonstrates that, in subjects who are facing forward, bipolar binaural stochastic galvanic stimulation of the vestibular system leads to coherent stochastic mediolateral postural sway, but it does not lead to coherent stochastic anteroposterior postural sway. Our finding that the coherency was highest for the 1- to 2-Hz stochastic vestibular stimulation signal may be due to the intrinsic dynamics of the quasi-static postural control system. In particular, it may result from the effects of the vestibular stimulus simply being superimposed upon the quiet-standing COP displacements. By utilizing stochastic stimulation signals, we ensured that the subjects could not predict a change in the vestibular stimulus. Thus, our findings indicate that subjects can act as ”responders” to galvanic vestibular stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050623
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    Loading during the stance phase of walking in humans increases the extensor EMG amplitude but does not change the duration of the step cycle (1999)
    Springer
    Experimental brain research 124 (1999), S. 363-370 
    Details
    ISSN: 1432-1106
    Keywords: Key words Locomotion ; Load ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Prior work from mammals suggests that load experienced by extensor muscles of the hindlimbs (i.e. Duysens and Pearson 1980; Pearson and Collins 1993; Fouad and Pearson 1997) or cutaneous afferents from the plantar surface of the foot (Duysens and Pearson 1976; Guertin et al. 1995) enhances activity in extensor muscles during the stance phase, and delays the onset of flexor activity associated with the swing phase. The presumed functional significance of this phenomenon is that extensor activity of the supporting limb during walking can: (a) reinforce the supporting function in proportion to the load experienced, and (b) prolong the stance phase until unloading of the limb has occurred. Whether a similar functional role exists for load-sensitive afferents during walking in the human is unknown. In this study, the effect of adding or removing a substantial load (30% of body weight) at the centre of mass was studied in healthy adult human subjects. Loads were applied near the centre of mass to avoid the need for postural adjustments which might confound the interpretation of the results. Subjects walked on a treadmill with either: (a) a sustained increase or decrease in load, or (b) a sudden unexpected increase or decrease in load. In general, subjects responded to the changes in load by changing the amplitude of the extensor electromyographic (EMG) bursts. For example, with sudden unexpected additions in load, the average increase in amplitude was 40% for the soleus across the stance phase, and 134% for the quadriceps during the early part of the stance phase. Extensor EMGs increased with both sustained and sudden increases in load. Extensor EMG durations also increased (average increase in duration of 4% for soleus with sudden loading, and 7% for sustained loading). Cycle duration hardly changed (average increase of 0.5% with both sudden and sustained loading). These results differ from those of infants subjected to a similar perturbation during supported walking. A large change in timing (i.e. an increase in the duration of the stance phase by 30% and the step cycle by 28%) was seen in the infants, with no change in the amplitude of the EMG burst (Yang et al. 1998). These results suggest that the central nervous system can control the timing and amplitude of extensor EMG activity in response to loading independently. Maturation of the two components most likely occurs independently. In the adult, independent control of the two components may provide greater flexibility of the response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050633
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    Inhibitory control of competing motor memories (1999)
    Springer
    Experimental brain research 126 (1999), S. 235-251 
    Details
    ISSN: 1432-1106
    Keywords: Key words Motor learning and memory ; Perseveration ; Prefrontal cortex ; Reversal learning ; Basal ganglia ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The ability to inhibit previously learned visuomotor associations is essential for efficient learning of novel behaviors. While the neural basis of the system that might control interactions between competing motor memories is not known, it has been demonstrated that animals with ventral and orbital prefrontal cortex (PFC) deficits have particular difficulties in learning to withhold responses to previously conditioned sensory stimuli. Here we measured regional cerebral blood flow (rCBF), using positron emission tomography, during learning of a novel motor task that required inhibition of a previously learned motor memory. Subjects (n=24) learned reaching movements in a force field (field A). After a variable time interval, some subjects (n=15) learned to reach in a field with a reversed pattern of forces (field B). When the time interval was short (10 min), learning in field B was coincident with a reactivation of regions that had become initially activated during learning in field A: the left putamen and bilaterally in the dorsolateral PFC. Behaviorally, this was accompanied with perseveration that lasted for hundreds of movements, suggesting an instantiation of the internal model for field A during learning in field B. Neither the reactivation nor the perseveration were observed in a different group of subjects that learned field B at 5.5 h. We found that the regions which significantly differentiated the two groups during learning of B were in the ventrolateral PFC (bilaterally): there were sharp decreases in rCBF here in the 5.5 group but not in the 10-min group. At 5.5 h motor learning again involved the striatum, but this time in the left caudate. Neither the caudate nor the ventral PFC had exhibited learning-related activity in field A. Instead, they showed changes in rCBF during the reversal of the learning problem when the previously acquired motor memory was successfully gated. The results demonstrate that: (1) perseveration of a competing motor memory may be linked to reactivation of the neural circuit that participated in acquiring that memory, and (2) the ventral PFC may play an important role in the inhibitory control of the competing motor memory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050733
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    Pathways of interhemispheric transfer in normals and in a split-brain subject A positron emission tomography study (1999)
    Springer
    Experimental brain research 126 (1999), S. 451-458 
    Details
    ISSN: 1432-1106
    Keywords: Key words Corpus callosum ; Interhemispheric transfer ; Positron emission tomography ; Split brain ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We studied with PET the intra- and interhemispheric pathways subserving a simple, speeded-up visuomotor task. Six normal subjects and one patient with a complete section of the corpus callosum (M.E.) underwent regional cerebral blood flow (rCBF) measurements under conditions of lateralized tachistoscopic visual presentations in a simple manual reaction time paradigm. Confirming previous behavioural findings, we found that on average crossed hand and/or hemifield conditions, i.e. those requiring an interhemispheric transfer of information, yielded a longer RT than uncrossed conditions. This difference (0.7 ms) was dramatically larger (45.6 ms) in the callosum-sectioned patient M.E. In normal subjects the cortical areas selectively activated in uncrossed and crossed conditions were different. In the former condition, most activation foci were anterior to the ventral anterior commissure (VAC) plane, whereas in the latter there was a prevalent parietal and occipital activation. This shows that a simple model in which the cortical visuo-motor pathways are similar in the intra- and the interhemispheric condition, with an extra callosal route for the latter, is too simplistic. Furthermore, these results suggest that the bulk of visuomotor interhemispheric transfer takes place through the widespread callosal fibres interconnecting the parietal cortices of the two hemispheres. The pattern of activation in the two crossing conditions was markedly different in M.E., in whom interhemispheric transfer might take place via his intact anterior commissure or subcortical commissures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050752
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    Localization of a seen finger is based exclusively on proprioception and on vision of the finger (1999)
    Springer
    Experimental brain research 125 (1999), S. 43-49 
    Details
    ISSN: 1432-1106
    Keywords: Key words Proprioception ; Visual localization ; Visual context ; Multisensory integration ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In a previous study we investigated how the CNS combines simultaneous visual and proprioceptive information about the position of the finger. We found that localization of the index finger of a seen hand was more precise (a smaller variance) than could reasonably be expected from the precision of localization on the basis of vision only and proprioception only. This suggests that, in localizing the tip of the index finger of a seen hand, the CNS may make use of more information than proprioceptive information and visual information about the fingertip. In the present study we investigate whether this additional information stems from additional sources of sensory information. In experiment 1 we tested whether seeing an entire arm instead of only the fingertip gives rise to a more precise proprioceptive and/or visual localization of that fingertip. In experiment 2 we checked whether the presence of a structured visual environment leads to a more precise proprioceptive localization of the index finger of an unseen hand. In experiment 3 we investigated whether looking in the direction of the index finger of an unseen hand improves proprioceptive localization of that finger. We found no significant effect in any of the experiments. The results refute the hypothesis that the investigated effects can explain the previously reported very precise localization of a seen hand. This suggests that localization of a seen finger is based exclusively on proprioception and on vision of the finger. The results suggest that these sensory signals may contain more information than is described by the magnitude of their variances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050656
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    Comparison of variability of initial kinematics and endpoints of reaching movements (1999)
    Springer
    Experimental brain research 125 (1999), S. 139-152 
    Details
    ISSN: 1432-1106
    Keywords: Key words Reaching movements ; Direction ; Amplitude ; Initial kinematics ; Spatial variability ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The accuracy of reaching movements to memorized visual target locations is presumed to be determined largely by central planning processes before movement onset. If so, then the initial kinematics of a pointing movement should predict its endpoint. Our study examined this hypothesis by testing the correlation between peak acceleration, peak velocity, and movement amplitude and the correspondence between the respective spatial positions of these kinematic landmarks. Subjects made planar horizontal reaching movements to targets located at five different distances and along five radially arrayed directions without visual feedback during the movements.The spatial dispersion of the positions of peak acceleration, peak velocity, and endpoint all tended to form ellipses oriented along the movement trajectory. However, whereas the peaks of acceleration and velocity scaled strongly with movement amplitude for all of the movements made at the five target distances in any one direction, the correlations with movement amplitude were more modest for trajectories aimed at each target separately. Furthermore, the spatial variability in direction and extent of the distribution of positions of peak acceleration and peak velocity did not scale differently with target distance, whereas they did for endpoint distributions. Therefore, certain features of the final kinematics are evident in the early kinematics of the movements as predicted by the hypothesis that they reflect planning processes. However, endpoint distributions were not completely predetermined by the Initial kinematics. In contrast, multivariate analysis suggests that adjustments to movement duration help compensate for the variability of the initial kinematics to achieve desired movement amplitude. These compensatory adjustments do not contradict the general conclusion that the systematic patterns in the spatial variability observed in this study reflect planning processes. On the contrary, and consistent with that conclusion, our results provide further evidence that direction and extent of reaching movements are planned and determined in parallel over time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050669
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    Pointing in 3D space to remembered targets II: Effects of movement speed toward kinesthetically defined targets (1999)
    Springer
    Experimental brain research 125 (1999), S. 200-210 
    Details
    ISSN: 1432-1106
    Keywords: Key words Three-dimensional pointing ; Human ; Remembered targets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The accuracy of visually guided pointing movements decreases with speed. We have shown that for movements to a visually defined remembered target, the variability of the final arm endpoint position does not depend on movement speed. We put forward a hypothesis that this observation can be explained by suggesting that movements directed at remembered targets are produced without ongoing corrections. In the present study, this hypothesis was tested for pointing movements in 3D space to kinesthetically defined remembered targets. Passive versus active acquisition of kinesthetic information was contrasted. Pointing errors, movement kinematics, and joint-angle coordination were analyzed. The movements were performed at a slow speed (average peak tangential velocity of about 1.2 m/s) and at a fast speed (2.7 m/s). No visual feedback was allowed during the target presentation or the movement. Variability in the final position of the arm endpoint did not increase with speed in either the active or the passive condition. Variability in the final values of the arm-orientation angles determining the position of the forearm and of the upper arm in space was also speed invariant. This invariance occurred despite the fact that angular velocities increased by a factor of two for all the angles involved. The speed-invariant variability supports the hypothesis that there is an absence of ongoing corrections for movements to remembered targets: in the case of a slower movement, where there is more time for movement correction, the final arm endpoint variability did not decrease. In contrast to variability in the final endpoint position, the variability in the peak tangential acceleration increased significantly with movement speed. This may imply that the nervous system adopts one of two strategies: either the final endpoint position is not encoded in terms of muscle torques or there is a special on-line mechanism that adjusts movement deceleration according to the muscle-torque variability at the initial stage of the movement. The final endpoint position was on average farther from the shoulder than the target. Constant radial-distance errors were speed dependent in both the active and the passive conditions. In the fast speed conditions, the radial distance overshoots of the targets increased. This increase in radial-distance overshoot with movement speed can be explained by the hypothesis that the final arm position is not predetermined in these experimental conditions, but is defined during the movement by a feedforward or feedback mechanism with an internal delay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050674
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    Modulation of the biceps femoris tendon jerk reflex during human locomotion (1999)
    Springer
    Experimental brain research 125 (1999), S. 265-270 
    Details
    ISSN: 1432-1106
    Keywords: Key words Tendon reflexes ; Biceps femoris ; Gait ; Ia afferents ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  During gait it is generally accepted that there is a reduction in amplitude of H-reflexes as compared to standing. For short-latency stretch reflexes, however, it is less clear whether a similar reduction in reflex gain is present during locomotion. Stretches of constant amplitude are hard to produce under these circumstances and for this reason some previous studies on the biceps femoris (BF) have used ”reduced gait” in which the stimulated leg is stepping on the spot while the contralateral leg is walking on a treadmill. With this method it was possible to show that BF tendon jerk reflexes are larger at end swing and therefore are likely to contribute to the EMG burst normally occurring in that part of the step cycle when the BF is rapidly stretched. In the present study two questions were addressed: first, whether the reflex is different in size during gait compared to standing and, second, whether it is modulated in size during the gait cycle not only during reduced but also during normal gait. It was found that during both types of gait there was a general reflex depression with regard to the respective control values obtained during standing at similar EMG activity levels. In previous studies on soleus and quadriceps, discrepancies between EMG activity and reflex amplitude have been ascribed to changes in presynaptic inhibition of Ia terminals mediating the afferent volley of the reflex. Based on the data presented, this may also be true for the BF. In both normal and reduced gait the reflex was similarly modulated in size, showing a maximum at the end of swing. This similarity implies that reduced gait may be useful as an acceptable alternative for normal gait in studies on phase-dependent reflex modulation during locomotion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050682
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    Effects of voluntary hyperventilation on cortical sensory responses Electroencephalographic and magnetoencephalographic studies (1999)
    Springer
    Experimental brain research 125 (1999), S. 248-254 
    Details
    ISSN: 1432-1106
    Keywords: Key words Hyperventilation ; Magnetoencephalography ; Somatosensory cortex ; Auditory cortex ; Somatosensory evoked response ; Auditory evoked response ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  It is well established that voluntary hyperventilation (HV) slows down electroencephalographic (EEG) rhythms. Little information is available, however, on the effects of HV on cortical responses elicited by sensory stimulation. In the present study, we recorded auditory evoked potentials (AEPs) and magnetic fields (AEFs), and somatosensory evoked magnetic fields (SEFs) from healthy subjects before, during, and after a 3- to 5-min period of voluntary HV. The effectiveness of HV was verified by measuring the end-tidal CO2 levels. Long-latency (100–200 ms) AEPs and long-latency AEFs originating at the supratemporal auditory cortex, as well as long-latency SEFs from the primary somatosensory cortex (SI) and from the opercular somatosensory cortex (OC), were all reduced during HV. The short-latency SEFs from SI were clearly less modified, there being, however, a slight reduction of the earliest cortical excitatory response, the N20m deflection. A middle-latency SEF deflection from SI at about 60 ms (P60 m) was slightly increased. For AEFs and SEFs, the center-of-gravity locations of the activated neuronal populations were not changed during HV. All amplitude changes returned to baseline levels within 10 min after the end of HV. The AEPs were not altered when the subjects breathed 5% CO2 in air in a hyperventilation-like manner, which prevented the development of hypocapnia. We conclude that moderate HV suppresses long-latency evoked responses from the primary projection cortices, while the early responses are less reduced. The reduction of long-latency responses is probably mediated by hypocapnia rather than by other nonspecific effects of HV. It is suggested that increased neuronal excitability caused by HV-induced hypocapnia leads to spontaneous and/or asynchronous firing of cortical neurones, which in turn reduces stimulus-locked synaptic events.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050680
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    The oculomanual coordination control center takes into account the mechanical properties of the arm (1999)
    Springer
    Experimental brain research 124 (1999), S. 42-52 
    Details
    ISSN: 1432-1106
    Keywords: Key words Ocular tracking ; Oculomanual coordination ; Electromyography ; Internal model ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  When the eyes and arm are involved in a tracking task, the characteristics of each system differ from those observed when they act alone: smooth pursuit (SP) latency decreases from 130 ms in external target tracking tasks to 0 ms in self-moved target tracking tasks. Two models have been proposed to explain this coordination. The common command model suggests that the same command be addressed to the two sensorimotor systems, which are otherwise organized in parallel, while the coordination control model proposes that coordination is due to a mutual exchange of information between the motor systems. In both cases, the interaction should take into account the dynamic differences between the two systems. However, the nature of the adaptation depends on the model. During self-moved target tracking a perturbation was applied to the arm through the use of an electromagnetic brake. A randomized perturbation of the arm increased the arm motor reaction time without affecting SP. In contrast, a constant perturbation produced an adaptation of the coordination control characterized by a decrease in arm latency and an increase in SP latency relative to motor command. This brought the arm-to-SP latency back to 0 ms. These results support the coordination control model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050598
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    Stronger occipital cortical activation to lower than upper visual field stimuli Neuromagnetic recordings (1999)
    Springer
    Experimental brain research 124 (1999), S. 287-294 
    Details
    ISSN: 1432-1106
    Keywords: Key words Magnetoencephalography ; V1 cortex ; V2 cortex ; V6 complex ; Horizontal meridian ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We recorded whole-scalp magnetoencephalographic (MEG) responses to black-and-white checkerboards to study whether the human cortical responses are quantitatively similar to stimulation of the lower and upper visual field at small, 0–6°, eccentricities. All stimuli evoked strongoccipital responses peaking at 50–100 ms (mean 75 ms). The activation was modeled with a single equivalent current dipole in the contralateral occipital cortex, close to the calcarine fissure, agreeing with an activation of the V1/V2 cortex. The dipole was, on average, twice as strong to lower than to upper field stimuli. Responses to hemifield stimuli that extended to both lower and upper fields resembled the responses to lower field stimuli in source current direction and strength. These results agree with psychophysical data, which indicate lower visual field advantage in complex visual processing. Parieto-occipital responses in the putative V6 complex were similar to lower and upper field stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050625
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    The uncontrolled manifold concept: identifying control variables for a functional task (1999)
    Springer
    Experimental brain research 126 (1999), S. 289-306 
    Details
    ISSN: 1432-1106
    Keywords: Key words Motor control ; Trajectory formation ; Coordination ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The degrees of freedom problem is often posed by asking which of the many possible degrees of freedom does the nervous system control? By implication, other degrees of freedom are not controlled. We give an operational meaning to ”controlled” and ”uncontrolled” and describe a method of analysis through which hypotheses about controlled and uncontrolled degrees of freedom can be tested. In this conception, control refers to stabilization, so that lack of control implies reduced stability. The method was used to analyze an experiment on the sit-to-stand transition. By testing different hypotheses about the controlled variables, we systematically approximated the structure of control in joint space. We found that, for the task of sit-to-stand, the position of the center of mass in the sagittal plane was controlled. The horizontal head position and the position of the hand were controlled less stably, while vertical head position appears to be no more controlled than joint motions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050738
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    Development of dynamic vision based on motion contrast (1999)
    Springer
    Experimental brain research 124 (1999), S. 469-473 
    Details
    ISSN: 1432-1106
    Keywords: Key words Form from motion ; Visual development ; Visual acuity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The development of dynamic vision was investigated in 400 healthy subjects (200 females and 200 males) aged between 4 and 24 years. The test consisted of a computer-generated random-dot kinematogram in which a Landolt ring was briefly presented as a form-from-motion stimulus. Motion contrast between the ring and background was varied in terms of the percentage of dots moving coherently within the ring in four levels (100%, 50%, 30%, and 20%). The subject’s task was to indicate the position of a gap in the ring (left, right, top, bottom). Results show a clear increase in performance with age for all motion contrast levels, with the greatest changes for the lowest levels. Adult performance was reached at the age of 15 years. Luminance-based static acuity measured with the Landolt test was poorly correlated with acuity for its form-from-motion analogue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050642
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    Remembered positions: stored locations or stored postures? (1999)
    Springer
    Experimental brain research 124 (1999), S. 503-512 
    Details
    ISSN: 1432-1106
    Keywords: Key words Reaching movements ; Memory for positions ; Laterality ; Posture copying ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Many recent studies indicate that memory for final position is superior to memory for movement. There is ambiguity about what is meant by the term final position, however. Is it final spatial location or final posture? According to a recently proposed theory by Rosenbaum et al., which maintains that stored postures form the basis for movement planning, when people try to return to recently reached positions, they should try to adopt the postures they just occupied. An alternative view, which holds that movements are primarily planned with respect to spatial locations, predicts that subjects should tend to return to places in external space. We describe an experiment that tested these opposing predictions. The experiment relied on the notion that if people store and use postures, they should ”copy” the posture adopted with one arm to the other arm when possible. The results support this hypothesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050646
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    Cortical control of optokinetic nystagmus in humans: a positron emission tomography study (1999)
    Springer
    Experimental brain research 126 (1999), S. 149-159 
    Details
    ISSN: 1432-1106
    Keywords: Key words Optokinetic nystagmus ; Positron emission tomography ; Visual motion ; Area V5 ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Positron emission tomography (PET) was used to address the issue of physiological changes in the cerebral cortex associated to optokinetic nystagmus (OKN) in humans. We studied regional cerebral blood flow in eight volunteers during reflexive induction of OKN by a pattern of dots moving unidirectionally (toward the left side). We used two control conditions, with subjects passively viewing either stationary or incoherently moving dots. This paradigm was designed in order to differentiate the OKN-related activations from blood flow changes related to visual motion. When compared with the stationary condition, OKN activated a set of occipital areas known to be sensitive to visual motion. Bilateral activation was found in the striate cortex (V1) and the parieto-occipital fissure, while area V5, the intraparietal sulcus, and the pulvinar were activated only in the left hemisphere. When compared with incoherent motion, OKN activated the V1 and the parieto-occipital fissure bilaterally and the right lingual gyrus, while a signal decrease was observed in the V5 region in both hemispheres. No significant signal changes were found in areas implicated in saccades or in processing vestibular information. These results indicate that processing of OKN-related information is associated with neural activity in a specific set of visual motion areas and suggest that this network can be asymmetrically activated by a strictly unidirectional stimulation. Results are also discussed in terms of the specific kinds of OKN-related information processing subserved by each area in this network.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050725
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    Listing’s plane rotation with convergence: role of disparity, accommodation, and depth perception (1999)
    Springer
    Experimental brain research 126 (1999), S. 175-186 
    Details
    ISSN: 1432-1106
    Keywords: Key words Listing’s plane ; Vergence ; Binocular ; Eye movements ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Earlier studies have reported temporal rotation of Listing’s plane with convergence of the eyes causing torsion, which is dependent on eye elevation. The amount by which the planes rotate differs from study to study. To gain insight into the functional significance of the temporal tilt of Listing’s plane for vision, we examined whether the rotation of the plane depends on the visual conditions, namely on the stimuli driving vergence. In different conditions, accommodative vergence, disparity-vergence, combinations of disparity with accommodation or depth perception were used and the resulting rotation of Listing’s plane was measured. Our findings show, for the first time, that the relationship between convergence and Listing’s-plane temporal rotation depends on the stimuli driving vergence. When the stimulus contains only disparity cues, vergence and Listing’s plane rotate immediately and consistently among subjects. Accommodative vergence, the mutual couplings between vergence and accommodation, can influence the orientation of Listing’s plane, but they do so in a idiosyncratic way. The largest rotation was elicited by stereograms combining disparity-vergence with depth perception. These findings support the idea of a functional role of Listing’s plane rotation for binocular vision, perhaps for depth perception.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050727
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    Grip forces exerted against stationary held objects during gravity changes (1999)
    Springer
    Experimental brain research 126 (1999), S. 205-214 
    Details
    ISSN: 1432-1106
    Keywords: Key words Grip force ; Force control ; Parabolic flight ; Microgravity ; Hypergravity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In the present study, grip forces exerted against a stationary held object were recorded during parabolic flights. Such flight maneuvers induce changes of gravity with two periods of hypergravity, associated with a doubling of normal terrestrial gravity, and a 20 s period of microgravity. Accordingly, the object’s weight changed from being twice as heavy as normally experienced and weightless. Grip-force recordings demonstrated that force control was seriously disturbed only during the first experience of hyper- and microgravity, with the grip forces being exceedingly high and yielding irregular fluctuations. Thereafter, however, grip force traces were smooth, the force level was scaled to the object’s weight under normal and high-G conditions, and the grip force changed in parallel with the weight during the transitions between hyper- and microgravity. In addition, during weightlessness, when virtually no force was necessary to stabilize the object, a low force was established, which obviously represented a reasonable safety margin for preventing possible perturbations. Thus, all relevant aspects of grip-force control observed under normal gravity conditions were preserved during gravity changes induced by parabolic flights. Hence, grip-force control mechanisms were able to cope with hyper- and microgravity, either by incorporating relevant receptor signals, such as those originating from cutaneous mechanoreceptors, or by adequately including perceived gravity signals into control programs. However, the adaptation to the uncommon gravity conditions was not complete following the first experience; finer tuning of the control system to both hyper- and microgravity continued over the measurement interval, presumably with a longer observation period being necessary before a stable performance can be reached.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050730
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    Optokinetic nystagmus with spontaneous reversal of transparent motion perception (1999)
    Springer
    Experimental brain research 129 (1999), S. 156-160 
    Details
    ISSN: 1432-1106
    Keywords: Key words Optokinetic nystagmus ; Depth-from-motion ; Transparent motion ; Ambiguous ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  When two visual patterns moving in opposite directions are superimposed, they appear to be at different depths and to slide over each other. Because the stimulus does not specify the depth-order between the surfaces, this transparent motion perception is essentially ambiguous. With prolonged observation, the perceived depth-order of the two moving surfaces reverses spontaneously. In the present study, the correlation between the perceived direction of transparent motion and optokinetic nystagmus (OKN) was examined. While viewing superimposed random-dot patterns moving in opposite horizontal or vertical directions, subjects attempted to fixate the center of the stimulus, while paying attention to either the near or far depth plane, and reported any changes of the direction of surface-motion at the attended depth. Even with attention focused on a particular depth, the spontaneous reversal of transparent motion perception still occurred. This indicates that the perceptual reversal may reflect a preattentive mechanism for depth-from-motion. Furthermore, the OKN slow-phase tended to be in the same direction as the perceived motion of the surface at the attended depth. These results support the idea that the mechanisms for OKN maintenance are sensitive to perception of depth-from-motion and, therefore, cortically mediated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050946
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    Coordination of reaching and grasping by capitalizing on obstacle avoidance and other constraints (1999)
    Springer
    Experimental brain research 128 (1999), S. 92-100 
    Details
    ISSN: 1432-1106
    Keywords: Key words Reaching movements ; Grasping movements ; Prehension ; Manual control ; Computational model ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Reaching and grasping an object can be viewed as the solution of a multiple-constraint satisfaction problem. The constraints include contact with the object with the appropriate effectors in the correct positions as well as generation of a collision-free trajectory. We have developed a computational model that simulates reaching and grasping based on these notions. The model, rendered as an animation program, reproduces many basic features of the kinematics of human reaching and grasping behavior. The core assumptions of the model are: (1) tasks are defined by flexibly organized constraint hierarchies; (2) manual positioning acts, including prehension acts, are first specified with respect to goal postures and then are specified with respect to movements towards those goal postures; (3) goal postures are found by identifying the stored posture that is most promising for the task, as determined by the constraint hierarchy, and then by generating postures that are more and more dissimilar to the most-promising stored posture until a deadline is reached, at which time the best posture that was found during the search is defined as the goal posture; (4) depending on when the best posture was encountered in the search, the deadline for the search in the next trial is either increased or decreased; (5) specification of a movement to the goal posture begins with straight-line interpolation in joint space between the starting posture and goal posture; (6) if an internal simulation of this default movement suggests that it will result in collision with an obstacle, the movement can be reshaped until an acceptable movement is found or until time runs out; (7) movement reshaping occurs by identifying a via posture that serves as a body position to which the actor moves from the starting posture and then back to the starting posture, while simultaneously making the main movement from the starting posture to the goal posture; (8) the via posture is identified using the same posture-generating algorithm as used to identify the goal posture. These processes are used both for arm positioning and, with some elaboration, for prehension. The model solves a number of problems with an earlier model, although it leaves some other problems unresolved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050823
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    Target viewing time and velocity effects on prehension (1999)
    Springer
    Experimental brain research 127 (1999), S. 83-94 
    Details
    ISSN: 1432-1106
    Keywords: Key words Target interception ; Reaching ; Grasping ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The goal of the present study was to understand which characteristics (movement time or velocity) of target motion are important in the control and coordination of the transport and grasp-preshape components of prehensile movements during an interception task. Subjects were required to reach toward, grasp and lift an object as it entered a target area. Targets approached along a track at four velocities (500, 750, 1000 and 1250 mm/s) which were presented in two conditions. In the distance-controlled condition, targets moving at all velocities traveled the same distance. In the viewing-time-controlled condition, combinations of velocity and starting distances were performed such that the moving target was visible for 1000 ms for all trials. Analyses of kinematic data revealed that when, target distance was controlled, velocity affected all transport-dependent measures; however, when viewing time was controlled, these dependent measures were no longer affected by target velocity. Thus, the use of velocity information was limited in the viewing-time-controlled condition, and subjects used other information, such as target movement time, when generating the transport component of the prehensile movement. For the grasp-preshape component, both peak aperture and peak-aperture velocity increased as target velocity increased, regardless of condition, indicating that target velocity was used to control the spatial aspects of aperture formation. However, the timing of peak aperture was affected by target velocity in the distance-controlled condition, but not in the viewing-time-controlled condition. These results provide evidence for the autonomous generation of the spatial and temporal aspects of grasp preshape. Thus, an independence between the transport and grasp-preshape phases was found, whereby the use of target velocity as a source of information for generating the transport component was limited; however, target velocity was an important source of information in the grasp-preshape phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050776
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    Hand deviations toward distractors Evidence for response competition (1999)
    Springer
    Experimental brain research 127 (1999), S. 207-212 
    Details
    ISSN: 1432-1106
    Keywords: Key words Attention ; Distractor interference ; Path deviation ; Horse race model ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  It has been suggested that, when movements are planned within cluttered environments, competing responses programmed to distracting stimuli are inhibited based on their relation to the action being performed. Further, as a result of this inhibition, the path of the movement made to the target object deviates away from the distractor. In contrast to the object avoidance hypothesis, the results of the present study show that, for aiming movements made in environments in which distractors are present, the path of the movement veers toward the distractor. Moreover, the effects of the distractors on the movement trajectory were independent of the direction of limb movement. These findings suggest that, when a distractor is not a potential physical barrier, a response to the distractor may be activated along with the target response and, owing to temporal advantages, cause a deviation of the movement trajectory toward the distractor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050790
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    The reach-to-grasp movement in Parkinson’s disease: response to a simultaneous perturbation of object position and object size (1999)
    Springer
    Experimental brain research 125 (1999), S. 453-462 
    Details
    ISSN: 1432-1106
    Keywords: Key words Reach to grasp ; Human ; Perturbation ; Kinematics ; Motor control ; Parkinson’s disease ; Elderly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This study assessed the adaptive response of the reach-to-grasp movement of 12 Parkinson’s disease (PD) and 12 control subjects to a simultaneous perturbation of target object location and size. The main aim was to test further the reported dysfunction of PD subjects in the simultaneous activation of movement components. Participants were required to reach 30 cm to grasp a central illuminated cylinder of either small (0.7 cm) or large (8 cm) diameter. For a small percentage of trials (20/100) a visual perturbation was introduced unexpectedly at the onset of the reaching action. This consisted of a shift of illumination from the central cylinder to a cylinder of differing diameter, which was positioned 20° to the left (n=10) or to the right (n=10). The subject was required to grasp the newly illuminated cylinder. For the Parkinson’s disease subject group, the earliest response to this ’double’ perturbation was in the parameter of peak reaching acceleration, which was on average 50 ms earlier for ’double’ perturbed than for non-perturbed trials. The grasp component response followed more than 500 ms after the earliest transport response. For the control subjects initial signs of a response to the ’double’ perturbation were seen almost simultaneously in the transport parameter of peak arm deceleration, and in the manipulation parameter of maximum grip aperture, but these changes were not evident until more than 400 ms after movement onset. These results indicate that the basal ganglia can be identified as part of a circuit which is involved in the integration of parallel neutral pathways, and which exercise flexibility in the degree to which these components are ’coupled’ functionally. With basal ganglia dysfunction the activation of integration centres that at first gate the flow of information to the parallel channels of reach and grasp seems inefficient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050703
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    Control of mesenteric arterial tone in vitro in humans and rats (1999)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 359 (1999), S. 322-330 
    Details
    ISSN: 1432-1912
    Keywords: Key words Blood pressure ; Endothelium ; Human ; Mesenteric artery ; Rat ; Smooth muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The majority of the findings concerning arterial physiology and pathophysiology originate from studies with experimental animals, while only limited information exists about the functional characteristics of human arteries. Therefore, the aim of the present work was to compare the control of vascular tone in vitro in mesenteric arterial rings of corresponding size (outer diameter 0.75–1 mm) from humans and Wistar-Kyoto rats. The relaxations to acetylcholine (ACh) were clearly less marked in the mesenteric arteries of humans when compared with rats. How-ever, when calcium ionophore A23187 was used as the vasodilator, the endothelium-mediated relaxations did not significantly differ between these species. The NO synthase inhibitor N G-nitro-l-arginine methyl ester (l-NAME) attenuated the relaxations to ACh and A23187 in both groups. The endothelium-independent relaxations to the β-adrenoceptor agonist isoprenaline and the nitric oxide (NO)-donor nitroprusside were somewhat lower in human arteries, while vasodilation induced by the K+ channel opener cromakalim was similar between humans and rats. Arterial contractile sensitivity to noradrenaline and serotonin was slightly lower in human vessels, whereas contractile sensitivity to KCl was similar between these species. The contractions induced by cumulative addition of Ca2+ with noradrenaline as the agonist were effectively inhibited in both groups by the calcium channel blocker nifedipine, the effect of which was clearly more pronounced in human arteries. In conclusion, the control of vascular tone of isolated arteries of corresponding size from humans and rats appeared to be rather similar. The most marked differences between these species were the impaired endothelium-mediated dilation to ACh and the more pronounced effect of nifedipine on the Ca2+-induced contractions in human arteries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00005358
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    Abstinence symptoms following oral THC administration to humans (1999)
    Springer
    Psychopharmacology 141 (1999), S. 385-394 
    Details
    ISSN: 1432-2072
    Keywords: Key words Marijuana ; Human ; THC ; Withdrawal ; Dependence ; Tolerance ; Subjective effect ; Performance ; Food intake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Symptoms of dependence and withdrawal after the frequent administration of high doses (210 mg/day) of oral Δ9-tetrahydrocannabinol (THC) have been reported, yet little is known about dependence on lower oral THC doses, more relevant to levels attained by smoking marijuana. In a 20-day residential study, male (n = 6) and female (n = 6) marijuana smokers worked on five psychomotor tasks during the day (0915–1700 hours), and in the evening engaged in private or social recreational activities (1700–2330 hours); subjective-effects measures were completed 10 times/day, and a sleep questionnaire was completed each morning. Food and beverages were available ad libitum from 0830 to 2330 hours. Capsules were administered at 1000, 1400, 1800, and 2200 hours. Placebo THC was administered on days 1–3, 8–11, and 16–19. Active THC was administered on days 4–7 (20 mg qid) and on days 12–15 (30 mg qid). Both active doses of THC increased ratings of “High,”“Good Drug Effect,” and “Willingness to Take Dose Again” compared to baseline (days 1–3). THC also increased food intake by 35–45%, and decreased verbal interaction among participants compared to placebo baseline. Tolerance developed to the subjective effects of THC but not to its effects on food intake or social behavior. Abstinence from THC increased ratings of “Anxious,”“Depressed,” and “Irritable,” decreased the reported quantity and quality of sleep, and decreased food intake by 20–30% compared to baseline. These behavioral changes indicate that dependence develops following exposure to lower daily doses of THC than have been previously studied, suggesting that the alleviation of abstinence symptoms may contribute to the maintenance of daily marijuana use.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050848
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    Abstinence symptoms following smoked marijuana in humans (1999)
    Springer
    Psychopharmacology 141 (1999), S. 395-404 
    Details
    ISSN: 1432-2072
    Keywords: Key words Marijuana ; Dependence ; Withdrawal ; Human ; Tolerance ; Subjective effect ; Performance ; Residential laboratory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Symptoms of withdrawal after oral Δ9-tetrahydrocannabinol (THC) administration have been reported, yet little is known about the development of dependence on smoked marijuana in humans. In a 21-day residential study, marijuana smokers (n = 12) worked on five psychomotor tasks during the day (0915–1700 hours), and in the evening engaged in recreational activities (1700–2330 hours); subjective-effects measures were completed 10 times/day. Food and beverages were available ad libitum from 0830 to 2330 hours. Marijuana cigarettes (0.0, 1.8, 3.1% THC) were smoked at 1000, 1400, 1800, and 2200 hours. Placebo marijuana was administered on days 1–4 . One of the active marijuana doses was administered on days 5–8, followed by 4 days of placebo marijuana (days 9–12). The other concentration of active marijuana cigarettes was administered on days 13–16, followed by 4 days of placebo marijuana (days 17–20); the order in which the high and low THC-concentration marijuana cigarettes were administered was counter-balanced between groups. Both active doses of marijuana increased ratings of “High,” and “Good Drug Effect,” and increased food intake, while decreasing verbal interaction compared to the placebo baseline (days 1–4). Abstinence from active marijuana increased ratings such as “Anxious,”“Irritable,” and “Stomach pain,” and significantly decreased food intake compared to baseline. This empirical demonstration of withdrawal from smoked marijuana may suggest that daily marijuana use may be maintained, at least in part, by the alleviation of abstinence symptoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050849
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    The effects of tryptophan depletion and loading on laboratory aggression in men: time course and a food-restricted control (1999)
    Springer
    Psychopharmacology 142 (1999), S. 24-30 
    Details
    ISSN: 1432-2072
    Keywords: Key words Aggression ; Tryptophan ; Serotonin ; Human ; Diet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Some studies have shown that sharp reduction of L-tryptophan (Trp) concentration in plasma results in increases in laboratory-measured aggression. Conversely, raising plasma Trp has blunted aggression. These effects are presumably due to impaired or enhanced serotonin synthesis and neurotransmission in the brain. In this study, the laboratory-measured aggressive behavior of eight men under both Trp depletion (T-) and Trp loading (T+) conditions was compared to their aggressive behavior under food-restricted control conditions (overnight fast without an amino acid beverage). Subjects were provoked by periodic subtraction of money which was attributed to a fictitious other participant, and aggression was defined as the number of retaliatory responses the subject made ostensibly to reduce the earnings of the (fictitious) other participant. Following ingestion of the T- beverage, aggressive responding was significantly elevated relative to the food-restricted control condition, and this increased aggressive behavior became more pronounced across behavioral testing sessions on a time-course which paralleled previously documented decreases in plasma Trp concentrations. In contrast, no changes were observed in aggressive responding under T+ conditions relative to food-restricted conditions. These within-subject behavioral changes under depleted plasma Trp conditions support earlier indications of a role of serotonin in regulating aggression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050858
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    Effect of a selective dopamine D1 agonist (ABT-431) on smoked cocaine self-administration in humans (1999)
    Springer
    Psychopharmacology 143 (1999), S. 102-110 
    Details
    ISSN: 1432-2072
    Keywords: Key words Cocaine ; Human ; Self-administration ; D1 agonist ; Subjective effect ; Craving ; Cardiovascular effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rationale: Data in laboratory animals suggest that D1 receptor agonists may have potential utility for the treatment of cocaine abuse. Objective: The effects of ABT-431, a selective agonist at the dopamine D1 receptor, on the reinforcing, cardiovascular and subjective effects of cocaine were investigated in humans. Method: Nine experienced cocaine smokers (8M, 1F), participated in nine self-administration sessions while residing on an inpatient research unit: three doses of ABT-431 (0, 2, 4 mg IV) were each given in combination with three doses of smoked cocaine (0, 12, 50 mg). ABT-431 was intravenously administered over a 1-h period immediately prior to cocaine self-administration sessions. A six-trial choice procedure (cocaine versus $5 merchandise vouchers) was utilized, with sessions consisting of: (a) one sample trial, where participants received the cocaine dose available that day, and (b) five choice trials, where participants chose between the available cocaine dose and one merchandise voucher. Results: ABT-431 did not affect the number of times participants chose to smoke each dose of cocaine, but produced significant dose-dependent decreases in the subjective effects of cocaine, including ratings of “High,”“Stimulated,” dose liking, estimates of dose value, “Quality,” and “Potency.” Furthermore, there was a trend for ABT-431 (4 mg) to decrease cocaine craving. ABT-431 also increased heart rate, while decreasing systolic and diastolic pressure at each dose of cocaine. Conclusions: These data suggest that D1 agonists may have potential utility for the treatment of cocaine abuse.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050925
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    Rated well-being in relation to plasma concentrations of l- and d-methadone in satisfied and dissatisfied patients on methadone maintenance treatment (1999)
    Springer
    Psychopharmacology 143 (1999), S. 385-393 
    Details
    ISSN: 1432-2072
    Keywords: Key words Methadone maintenance treatment ; Chiral analysis ; Methadone ; Plasma ; Urine ; Abused drug ; Daily variation ; Rating scales ; Dose-adjustment ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rationale: One of the major problems in methadone maintenance treatment is to find optimal individual doses for the patients. Objective: The present study investigated whether the use of rating scales together with enantioselective analysis of l-methadone might facilitate dose adjustments in a clinical situation. Methods: Rating scales were used to evaluate subjective and objective signs of well-being in relation to plasma methadone concentrations in two groups of patients receiving methadone maintenance treatment. The first group (n = 25) was well-adjusted according to clinical observations and were satisfied with their methadone doses (86.2 ± 4.3 mg). The second group (n = 25) was in need of the methadone dose adjustment; they complained of low dosing, despite a dose level of 69.2 ± 4.0 mg/day. Results: Results indicated a significant correlation between dose and methadone concentration among dissatisfied patients only. The trough levels of d,l-methadone and l-methadone, as well as their elimination rates, were similar in the two groups of patients. There was a variable predominance of l- over d-methadone in plasma (ratio ≈1.2; range 0.7–3.6). Illicit use of drugs by the patients was related to the methadone dose and to satisfaction with the dose received. Increased illicit drug use among dissatisfied patients was successfully eliminated by raising the methadone dose. Subjective and objective ratings of the satisfied patients were quite stable throughout the evaluation period, whereas the ratings of the dissatisfied patients were unstable. These patients seemed to be more sensitive to low trough levels of methadone than the satisfied patients. Associations between the subjective and objective ratings and plasma methadone, along with background characteristics, were characterized by multiple regression analyses. The plasma concentrations of l-methadone were one of the most important explanatory variables in these analyses. Associations between well-being and methadone concentrations in plasma were stronger for l-methadone than for d,l-methadone. Conclusions: Selective measurements of the active isomer and the use of rating scales should be of clinical value when monitoring methadone maintenance treatment patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050963
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    Level of use of 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) in humans correlates with EEG power and coherence (1999)
    Springer
    Psychopharmacology 145 (1999), S. 82-90 
    Details
    ISSN: 1432-2072
    Keywords: Key words MDMA ; Ecstasy ; Human ; EEG ; Power ; Coherence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rationale: Despite animal studies implicating 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) in serotonergic neurotoxicity, there is little direct evidence of changes in neural function in humans who use MDMA as a recreational drug. Objective: The present study investigated whether there is a correlation between quantitative EEG variables (spectral power and coherence) and cognitive/mood variables, and level of prior use of MDMA. Methods: Twenty-three recreational MDMA users were studied. Resting EEG was recorded with eyes closed, using a 128-electrode geodesic net system, from which spectral power, peak frequency and coherence levels were calculated. Tests of intelligence (NART), immediate and delayed memory, frontal function (card sort task), and mood (BDI and PANAS scales) were also administered. Pearson correlation analyses were used to examine the relationship between these measures and the subject’s consumption of MDMA during the previous 12-month period. Partial correlation was used to control for the use of other recreational drugs. Results: MDMA use was positively correlated with absolute power in the alpha (8–12 Hz) and beta (12–20 Hz) frequency bands, but not with the delta (1–3 Hz) or theta (4–7 Hz) bands. MDMA use was negatively correlated with EEG coherence, a measure of synchrony between paired cortical locations, in posterior brain sites thought to overly the main visual association pathways of the occipito-parietal region. MDMA use did not correlate significantly with any of the mood/cognitive measures except the card sort task, with which it was weakly negatively correlated. Conclusions: Alpha power has been shown to be inversely related to mental function and has been used as an indirect measure of brain activation in both normal and abnormal states. Reduced coherence levels have been associated with dysfunctional connectivity in the brain in disorders such as dementia, white-matter disease and normal aging. Our results may indicate altered brain function correlated with prior MDMA use, and show that electroencephalography may be a cheap and effective tool for examining neurotoxic effects of MDMA and other drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130051035
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    Onset, magnitude and duration of opioid blockade produced by buprenorphine and naltrexone in humans (1999)
    Springer
    Psychopharmacology 145 (1999), S. 162-174 
    Details
    ISSN: 1432-2072
    Keywords: Key words Opioid blockade ; Buprenorphine ; Naltrexone ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rationale: One therapeutic benefit of mu opioid agonist or antagonist maintenance is the resultant attenuation of the effects of illicit opioids. It is important to characterize the development and duration of opioid blockade produced by buprenorphine, a novel opioid dependence pharmacotherapy. Objective: This study characterized the ability of buprenorphine to attenuate opioid effects during treatment initiation and discontinuation compared to naltrexone and placebo. Methods: Opioid-experienced volunteers (n = 8) participated in this 10-week, inpatient, double-blind, within-subject, crossover study. Five randomized conditions [buprenorphine (2 and 8 mg, sublingually), naltrexone (25 and 100 mg, PO) and placebo] were each examined during a 2-week period; the test drug was given for 7 days followed by a 7-day placebo wash-out. Cumulative doses of hydromorphone (0, 2 and 4 mg, IM, 45 min apart) were administered thrice-weekly corresponding with treatment and wash-out days 1, 3, and 5; behavioral, physiological and pharmacokinetic measures were collected. Results: Buprenorphine alone produced dose-related prototypic agonist effects during induction (i.e., positive mood, respiratory depression, miosis); tolerance developed only to the subjective effects. Buprenorphine 2 mg partially attenuated the effects of hydromorphone, while nearly complete attenuation was observed with 8 mg that lasted up to 72 h after discontinuation. Both naltrexone doses produced complete hydromorphone blockade after a single dose; blockade of the behavioral, but not physiological, effects persisted for 5 days after discontinuation of 100 mg. Conclusions: These data suggest that 2 mg buprenorphine is a sub-therapeutic maintenance dose, both buprenorphine 8 mg and naltrexone produce immediate and efficacious opioid blockade, and adequate protection against illicit opioids may be achieved with less-than-daily dosing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130051045
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    Zaleplon and triazolam in humans: acute behavioral effects and abuse potential (1999)
    Springer
    Psychopharmacology 145 (1999), S. 39-51 
    Details
    ISSN: 1432-2072
    Keywords: Key words Zaleplon ; Triazolam ; Benzodiazepine ; Hypnotics ; Learning ; Memory ; Abuse potential ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Zaleplon, a pyrazolopyrimidine that is under development as a hypnotic, produces its pharmacological effects at the benzodiazepine-recognition site on the GABAA benzodiazepine-receptor complex. Unlike most benzodiazepines, zaleplon binds selectively to the BZ1 (ω1) subtype of the benzodiazepine receptor. The present study compared the acute subject-rated effects, performance-impairing effects, and abuse potential of zaleplon and triazolam, a triazolobenzodiazepine hypnotic, in 14 healthy volunteers with histories of drug abuse. Zaleplon (25, 50, and 75 mg), triazolam (0.25, 0.5, and 0.75 mg) and placebo were administered orally in this double-blind, crossover study. Zaleplon and triazolam produced comparable dose-related effects on several subject-rated drug-effect questionnaires. Zaleplon and triazolam also produced comparable dose-dependent decrements on several performance tasks including balance, circular lights, digit-enter and recall, DSST, picture recall/recognition and repeated acquisition. Same-day and next-day subject-rated measures reflecting abuse potential (e.g., drug liking, good effects, and monetary street value) also suggest that zaleplon and triazolam were comparable. The only notable between-drug difference observed in the present study was that the time-action function of zaleplon differed from that of triazolam. The onset time, time to maximum drug effect, and duration of action were shorter with zaleplon than triazolam. Thus, despite its non-benzodiazepine structure and unique benzodiazepine-receptor binding profile, the behavioral pharmacological profile of zaleplon is similar to that of triazolam.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130051030
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    Effects of training dose and two- versus three-choice testing procedure on nicotine discrimination responding in humans (1999)
    Springer
    Psychopharmacology 145 (1999), S. 418-425 
    Details
    ISSN: 1432-2072
    Keywords: Key words Nicotine ; Drug discrimination ; Training conditions ; Testing conditions ; Three-choice procedure ; Subjective effect ; Human ; Smoking status
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rationale: Discrimination of a drug’s interoceptive stimulus effects often depends substantially on training and testing conditions. Objectives: We examined changes in nicotine discrimination behavior in humans as a function of lowering the training dose and of varying the discrimination testing procedure. Methods: Smokers and never-smokers (n=10 each) were initially trained to discriminate 20 µg/kg nicotine by nasal spray from placebo (0) and tested on generalization of discrimination responding across a range of doses from 0 to 20 µg/kg. Each subsequently learned to reliably discriminate progressively smaller doses of nicotine from placebo until his or her threshold dose for discrimination was identified (mean=2.7 µg/kg). A repeat testing of generalization responding across 0–20 µg/kg was then conducted, using placebo and the subject’s threshold dose as training doses. Generalization testing involved both two-choice and three-choice (novel response option) quantitative procedures. Results: A significant shift to the left was seen in nicotine-appropriate responding in the two-choice procedure when the nicotine training dose was lowered (i.e. from the first to the second test of generalization). In the three-choice procedure, however, there was no such leftward shift. Instead, in never-smokers, a flattening of nicotine-appropriate responding occurred with a lowering of the training dose, while novel-appropriate responding significantly increased. The subjective effects of ”head rush” and, in never-smokers only, ”jittery” also showed a shift to the left in their relationship with nicotine generalization dose when the training dose was lowered. Conclusions: These results confirm the importance of training and testing conditions on discrimination behavior and subjective drug responses within subjects and demonstrate the utility of the novel-response, three-choice procedure for assessing qualitatively different stimulus effects of novel drug doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130051076
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    Buprenorphine dosing every 1, 2, or 3 days in opioid-dependent patients (1999)
    Springer
    Psychopharmacology 146 (1999), S. 111-118 
    Details
    ISSN: 1432-2072
    Keywords: Key words Buprenorphine ; Heroin dependence ; Opioid dependence ; Human ; Opioid withdrawal ; Treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rationale: Administration of double the maintenance dose of buprenorphine has been shown to permit every-other-day dosing. Whether longer periods between dosing can be achieved is unknown. Objectives: To examine whether triple the maintenance dose can be administered every 72 h without opioid withdrawal or intoxication. Methods: Sixteen opioid-dependent outpatients each received three conditions (1) the maintenance dose of buprenorphine every 24 h, (2) double the maintenance dose every 48 h, and (3) triple the maintenance dose every 72 h under double-blind placebo-controlled conditions. Each conditions was imposed in a random sequence for 21–22 days. Self report and observer measures were taken at 24-h intervals. Results: No significant differences were observed on measures of opioid agonist and withdrawal effects between the dosing conditions. However, averaging effects across conditions may obscure important within-condition effects. When conditions were analyzed by individual days within a condition, several significant effects were observed. For example, 24 h after administration of triple the maintenance dose, significant effects were observed in eight opioid agonist measures. Also, 72 h after administration of triple the maintenance dose, significant effects were observed on four measures of withdrawal. Neither adverse medical reactions nor excessive opioid intoxication were observed. Conclusions: These results suggest that buprenorphine may be administered safely every 72 h by tripling the maintenance dose, with only minimal withdrawal complaints. Importantly, this 72-h dosing may permit patients to attend clinic thrice weekly without the use of take-home doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130051096
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    Working memory, executive processes and the effects of alcohol on Go/No-Go learning: testing a model of behavioral regulation and impulsivity (1999)
    Springer
    Psychopharmacology 146 (1999), S. 465-472 
    Details
    ISSN: 1432-2072
    Keywords: Key words Alcohol effect ; Impulsivity ; Working memory ; Executive function ; High-risk ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rationale: Impulsivity is associated with increased risk for alcoholism. Alcohol also may increase impulsive behavior, although little is known about the processes underlying this effect. Objectives: This study tested a model proposing that the executive processes of working memory (WM) and conditional associative learning (CAL) modulate behavioral inhibition. Subjects had either a positive (FHP) or a negative (FHN) family history of alcoholism. Hypotheses were that alcohol would increase Go/No-Go impulsive responding but only in subjects with low working memory capacity (low-WM), low-CAL ability, or FHP for alcoholism. The model also predicted that WM and CAL modulate inhibitory responses to contingency reversal on a Go/No-Go task. Methods: A Go/No-Go learning task with a midway contingency reversal was administered to 71 FHP and 78 FHN subjects when sober and after drinking one of two moderate doses of alcohol. WM (digits backward) and CAL (conditional spatial association task) were also assessed when sober. Results: Alcohol resulted in more false alarms but only in low-WM subjects. Both WM and CAL modulated learning to inhibit behavior after contingency reversal, suggesting separate modulation mechanisms for WM and CAL. Subjects with low- capacity WM and subjects with low-capacity CAL ability had more difficulty learning response inhibition after contingency reversal. FHPs and FHNs did not differ in their response to alcohol. Conclusions: The results support our model of the modulatory role of WM and CAL in the ongoing regulation of behavioral inhibitory systems. The results also suggest that individuals with low capacity WM are more susceptible to alcohol’s effect of increasing impulsive behavior, suggesting that alcohol reduces the capacity of working memory to modulate response inhibition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00005492
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    A controlled study of flumazenil-precipitated withdrawal in chronic low-dose benzodiazepine users (1999)
    Springer
    Psychopharmacology 147 (1999), S. 200-209 
    Details
    ISSN: 1432-2072
    Keywords: Key words Benzodiazepine ; Flumazenil ; Precipitated withdrawal ; Antagonist ; Physical dependence ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rationale: Preclinical studies of the benzodiazepine antagonist flumazenil (Romazicon®) have contributed to the understanding of the physical dependence associated with chronic benzodiazepine use; when administered to animals chronically pretreated with benzodiazepines, flumazenil precipitates a withdrawal syndrome. However, few controlled clinical studies have been conducted. Objectives: The objective was to characterize the effects of flumazenil in long-term users of therapeutic doses of benzodiazepines. Methods: The acute physiological, participant-rated, and observer-rated effects of intravenously administered flumazenil (1 mg/70 kg) and caffeine (300 mg/70 kg; active drug control) were evaluated in an experimental group of 13 long-term users (mean 4.6 years) of low therapeutic doses (mean 11.2 mg/day diazepam equivalent) relative to a matched group of 13 volunteers without prior exposure to benzodiazepines in a double-blind, placebo-controlled, mixed design. Results: Whereas the experimental group did not differ from the control group with respect to the effects of placebo, and both groups showed some changes in response to caffeine (e.g., increased blood pressure and anxiety scores), only the experimental group showed considerable changes in physiological measures, participant ratings (e.g., increased ratings of dizziness, blurred vision, heart pounding, feelings of unreality, pins and needles, nausea, sweatiness, noises louder than usual, jitteriness, things moving, sensitivity to touch), and observer ratings in response to flumazenil; in addition, four participants developed panic attacks. Conclusions: This study clearly demonstrates that flumazenil can precipitate symptoms commonly associated with benzodiazepine withdrawal in chronic low-dose benzodiazepine users.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130051161
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    Lorazepam impairs both visual and auditory perceptual priming (1999)
    Springer
    Psychopharmacology 147 (1999), S. 266-273 
    Details
    ISSN: 1432-2072
    Keywords: Key words Benzodiazepine ; Lorazepam ; Human ; Memory ; Auditory priming ; Visual priming ; Explicit memory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rationale: Lorazepam has been repeatedly shown to impair both explicit memory and perceptual priming, a form of implicit memory, in the visual domain. However, the effects of this benzodiazepine on priming in other perceptual domains, such as auditory priming, have never been explored. Objective:The present study investigated whether the deleterious effects of lorazepam on perceptual priming are restricted to the visual domain, or if they could be extended to the auditory domain. Methods: Thirty-two healthy volunteers were randomly assigned to two parallel groups, placebo and lorazepam 0.038 mg/kg. The drug was administered orally, following a double-blind procedure. In the same subjects, perceptual priming was assessed in the auditory and visual domains using similar word-stem completion tasks, and explicit memory was explored using a free- recall task. Results: Lorazepam markedly reduced free-recall performance for visually and auditorily presented words. Lorazepam equally impaired visual and auditory priming. In the auditory word-stem completion task, prior presentation of a word facilitated perception of its stem in the placebo group. This facilitation effect was not observed in the lorazepam group. The lorazepam-induced impairment of priming was not due to sedation or explicit contamination. Conclusion: These results indicate that the deleterious effects of lorazepam on priming are not restricted to the visual modality, but extend to the auditory modality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130051166
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    The use of vergence information in the programming of prehension (1999)
    Springer
    Experimental brain research 128 (1999), S. 578-582 
    Details
    ISSN: 1432-1106
    Keywords: Key words Prehension ; Binocular ; Vergence ; Distance perception ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Human prehension requires accurate information on the properties of an object and on the position of the object relative to the body. In principle, prehension might be more accurate with binocular rather than monocular vision. Previous studies have shown that the kinematics of prehension are altered when one eye is covered. Unfortunately, the source of the useful binocular information cannot be established using this approach. In the current study, we used a perturbation technique to explore whether the human nervous system uses a signal from vergence in prehension. Perturbing vergence caused predictable changes in the kinematics of prehension. Our results thus provide clear evidence that the nervous system uses vergence information in the programming of prehensile movement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050885
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    Does the coordination between posture and movement during human whole-body reaching ensure center of mass stabilization? (1999)
    Springer
    Experimental brain research 129 (1999), S. 134-146 
    Details
    ISSN: 1432-1106
    Keywords: Key words Coordination ; Posture ; Movement ; Anticipatory postural adjustments ; Axial synergy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The whole-body center of mass (CoM) has been classically regarded as the stabilized reference value for human voluntary movements executed upon a fixed base of support. Axial synergies (opposing displacements of head and trunk with hip segments) are believed to minimize antero-posterior (A/P) CoM displacements during forward trunk movements. It is also widely accepted that anticipatory postural adjustments (APAs) create forces of inertia that counteract disturbances arising from the moving segment(s). In the present study, we investigated CoM stabilization by axial synergies and APAs during a whole-body reaching task. Subjects reached towards an object placed on the ground in front of them in their sagittal plane using a strategy of coordinated trunk, knee, and hip flexion. The reaching task imposed constraints on arm-trajectory formation and equilibrium maintenance. To manipulate equilibrium constraints, differing conditions of distance and speed were imposed. The comparison of distance conditions suggested that axial synergies were not entirely devoted to CoM stabilization: backward A/P hip displacements reduced as head and trunk forward A/P displacements increased. Analysis of upper- and lower-body centers of mass in relation to the CoM also showed no strict minimization of A/P CoM displacements. Mechanical analysis of the effects of APAs revealed that, rather than acting to stabilize the CoM, APAs created necessary conditions for forward CoM displacement within the base of support in each condition. The results have implications for the CoM as the primary stabilized reference for posture and movement coordination during whole-body reaching and for the central control of posture and voluntary movement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050944
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    Effects of intrathecal clonidine injection on spinal reflexes and human locomotion in incomplete paraplegic subjects (1999)
    Springer
    Experimental brain research 129 (1999), S. 433-440 
    Details
    ISSN: 1432-1106
    Keywords: Key words Spasticity ; Gait ; Spinal cord ; Human ; Clonidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We studied the effect of the intrathecal (i.t.) injection of clonidine (30, 60 and 90 µg) on the polysynaptic spinal reflexes (PSR) elicited by electrical stimulation of flexor reflex afferents (FRA), monosynaptic reflex and gait of 11 subjects with spinal cord injuries. The effect of clonidine administration on gait velocity, stride amplitude and duration was measured in eight subjects who were able to walk. Five subjects were able to walk after intrathecal injection of clonidine and three were not able to stand up. Three subjects improved their gait velocity after clonidine administration; one (S6) increased his stride amplitude; the two others decreased their cycle durations. The tibialis anterior seemed to be more regularly activated during gait. Spasticity was reduced dramatically (P〈0.0001) after i.t. clonidine injection, but there was no statistically significant difference in the soleus H reflex (no effect on Hmax/Mmax). Clonidine administration decreased the amplitude of the early PSR (90–120 ms, N=4) and the threshold and maximal integrated EMG corresponding to the late response (140–450 ms, N=7). This effect was dose dependent (30, 60 and 90 µg). Placebo injection (N=4) caused no change. The changes in spinal reflexes, with a large reduction in spasticity, no change in motoneurone excitability and a large decrease in PSR, suggest that clonidine acts at a premotoneuronal level, possibly by presynaptic inhibition of group II fibres. The increase in gait velocity in three subjects could have been due to reduced spasticity or activation of spinal circuitry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050910
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    Object size effects on initial lifting forces under microgravity conditions (1999)
    Springer
    Experimental brain research 124 (1999), S. 422-428 
    Details
    ISSN: 1432-1106
    Keywords: Key words Lifting forces ; Size-weight illusion ; Microgravity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Individuals usually report for two objects of equal mass but different volume that the larger object feels lighter. This so-called size-weight illusion has been investigated for more than a century. The illusion is accompanied by increased forces, used to lift the larger object, resulting in a higher initial lifting speed and acceleration. The illusion holds when subjects know that the mass of the two objects is equal and it is likely that this also counts for the enlarged initial effort in lifting a larger box. Why should this happen? Under microgravity, subjects might be able to eliminate largely the weight-related component of the lifting force. Then, if persistent upward scaling of the weight-related force component had been the main cause of the elevated initial lifting force under normal gravity, this elevated force might disappear under microgravity. On the other hand, the elevated initial lifting effort in the large box would be preserved if it had been caused mainly by a persistent upward scaling of the force component, necessary to accelerate the object. To test whether the elevated initial lifting effort either persists or disappears under microgravity, a lifting experiment was carried out during brief periods of microgravity in parabolic flights. Subjects performed whole-body lifting movements with their feet strapped to the floor of the aircraft, using two 8-kg boxes of different volume. The subjects were aware of the equality of the box masses. The peak lifting forces declined almost instantaneously with approx. a factor 9 in the first lifting movements under microgravity compared with normal gravity, suggesting a rapid adaptation to the loss of weight. Though the overall speed of the lifting movement decreased under microgravity, the mean initial acceleration of the box over the first 200 ms of the lifting movement remained higher (P=0.030) in the large box (1.87±0.127 m/s2) compared with the small box (1.47±0.122 m/s2). Under normal gravity these accelerations were 3.30±0.159 m/s2 and 2.67±0.159 m/s2, respectively (P=0.008). A comparable trend was found in the initial lifting forces, being significant in the pooled gravity conditions (P=0.036) but not in separate tests on the normal gravity (P=0.109) and microgravity (P=0.169) condition. It is concluded that the elevated initial lifting effort with larger objects holds during short-term exposure to microgravity. This suggests that upward scaling of the force component, required to accelerate the larger box, is an important factor in the elevated initial lifting effort (and the associated size-weight illusion) under normal gravity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050638
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    Clustering of Pacinian corpuscle afferent fibres in the human median nerve (1999)
    Springer
    Experimental brain research 126 (1999), S. 399-409 
    Details
    ISSN: 1432-1106
    Keywords: Key words Microneurography ; Peripheral nerve ; Pacinian afferent ; Cutaneous mechanoreceptor ; Vibrotactile stimuli ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  To further study the functional organisation of human peripheral nerves, the intrafascicular arrangement of afferent fibres supplying Pacinian corpuscles (PCs) was explored by percutaneous microneurography using thin-calibre, concentric needle electrodes. In normal adults, 20 PC afferents were identified in 13 recording sites. Low-amplitude (less than 30 µm) vibratory stimuli to the skin were applied with tuning forks oscillating at 128 Hz or 256 Hz and response patterns of individual PC units were studied. In many recording sites, two, sometimes even three, PC afferents with adjacent or overlapping receptive fields in the hand were clustered in the nerve. The observed incidence in the records containing a certain number of PC units was compared with the expected probability calculated according to the hypothesis that all nerve fibres are randomly organised in peripheral nerves. The results suggested that PC afferents are partially segregated in the nerve. In addition, PC afferents were neighbouring on slowly adapting type II (SAII) units and skin sympathetic activity in individual fascicles. SAII units often innervated the same skin area as PC units, but did not respond to vibration. The data provided additional information regarding the functional organisation of the human peripheral nerve and the mechanisms underlying the sense of vibration in man with special regard to population behaviour of neighbouring PC mechanoreceptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050746
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    The development of postural adjustments during reaching in 6- to 18-month-old infants Evidence for two transitions (1999)
    Springer
    Experimental brain research 126 (1999), S. 517-528 
    Details
    ISSN: 1432-1106
    Keywords: Key words Motor development ; Reaching ; Anticipatory postural control ; EMG ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The present study focused on the developmental changes of postural adjustments accompanying reaching movements in healthy infants. We made a longitudinal study of ten infants between 6 and 18 months of age. During each session multiple surface electromyograms of arm, neck, trunk and leg muscles at the right side of the body were recorded during right-handed reaching movements in two positions (”upright sitting” in an infant chair and ”long-leg” sitting without support). Simultaneously the whole session was recorded on video. Comparable data were present from the same infants at 3–5 months. Additionally, 18 infants (8–15 months) were assessed once during similar reaching tasks, but in these infants electromyographic activity of the trunk and neck muscles at both sides of the body were recorded. Our data revealed two transitions in the development of postural adjustments. The first transition was present around 6 months of age. At this age the postural muscles were infrequently activated during reaching movements. At 8 months ample postural activity reappeared and the infants developed the ability to adapt the postural adjustments to task-specific constraints such as arm movement velocity or the sitting position at the onset of the reaching movement. The second transition occurred between 12 and 15 months. Before 15 months the infants did not show consistent anticipatory postural activity, but from 15 months onwards they did, particularly in the neck muscles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050760
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  • 87
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    Afferent input and cortical organisation: a study with magnetic stimulation (1999)
    Springer
    Experimental brain research 126 (1999), S. 536-544 
    Details
    ISSN: 1432-1106
    Keywords: Key words Magnetic brain stimulation ; Afferent input ; Motor cortex ; Plasticity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Previously, we had described a technique for investigating probable GABAergic cortical inhibitory circuits in conscious man using transcranial magnetic stimulation. This type of inhibition has been termed intracortical inhibition. During voluntary contraction, activity in the circuits responsible for this inhibition is reduced. The mechanism by which this reduction in activity is brought about is unknown. However, evidence exists to suggest that afferent input may be, at least in part, responsible for the reduction in inhibition. The experiments described here were designed to investigate this possibility further. The results of these experiments showed that afferent input, produced by electrical peri- pheral-nerve stimulation, reduced the level of intracortical inhibition. Also, motor imagery, which activates similar brain regions as overt movement, but does not result in afferent input, failed to produce significant changes in intracortical inhibition. We conclude from these results that afferent input is capable of altering activity in cortical inhibitory circuits. The relevance of these findings to the mechanisms involved in cortical reorganisation is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050762
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  • 88
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    The origin of ocular microtremor in man (1999)
    Springer
    Experimental brain research 126 (1999), S. 556-562 
    Details
    ISSN: 1432-1106
    Keywords: Key words Acceleration ; Ocular microtremor ; Eye movements ; Partial coherence ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A novel technique for the study of human eye movements was used to investigate the frequency components of ocular drift and microtremor in both eyes simultaneously. The tangential components of horizontal eye accelerations were recorded in seven healthy subjects using light-weight accelerometers mounted on scleral contact lenses during smooth pursuit movements, vestibulo-ocular reflexes and eccentric gaze with and without fixation. Spectral peaks were observed at low (up to 25 Hz) and high (60–90 Hz) frequencies. A multivariate analysis based on partial coherence analysis was used to correct for head movement. After correction, the signals were found to be coherent between the eyes over both low- and high-frequency ranges, irrespective of task, convergence or fixation. It is concluded that the frequency content of ocular drift and microtremor reflects the patterning of low-level drives to the extra-ocular muscle motor units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050764
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  • 89
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    The influence of stimulus temperature rise rate, adapting temperature, and stimulus duration on suprathreshold responses evoked by noxious heat in the glabrous skin of the limb Comparison of neuronal discharge in the rat spinal dorsal horn with human sensations (1999)
    Springer
    Experimental brain research 126 (1999), S. 482-494 
    Details
    ISSN: 1432-1106
    Keywords: Key words Suprathreshold heat pain ; Adapting temperature ; Temporal parameters ; Spinal dorsal horn neuron ; Descending control ; Rat ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The influence of stimulus temperature rise rate (2.5ºC/s, 5.0ºC/s, and 10.0ºC/s), adapting (baseline) temperature (25ºC, 30ºC, and 35ºC), and duration of peak stimulus temperature (1.0 s, 2.5 s, 5.0 s, and 10.0 s) on responses evoked by noxious heat stimuli of suprathreshold intensity was studied in wide dynamic range (WDR) neurons of the rat spinal dorsal horn. The spinal neuronal responses were compared with human psychophysical data obtained using the same stimuli. Noxious heat stimuli with a peak temperature of 54ºC were applied with a contact thermostimulator to the glabrous skin of the hindfoot in rats or to the palmar skin in humans. With the highest ramp rate and the highest adapting temperature, the sensory and spinal neuronal response latencies were decreased more than expected on the basis of the change in physical parameters of the stimulus. The magnitudes of sensory and spinal neuronal response were independent of the stimulus ramp rate, whereas pain magnitude estimates and spinal neuronal impulse counts evoked by the same peak stimulus temperature were increased with an increase in the adapting stimulus temperature. The onset latencies of pain reactions and spinal neuronal responses were independent of the peak stimulus duration, whereas the latency of the maximum discharge in spinal neurons increased with prolongation of the peak stimulus. The sensory magnitude estimate of pain and the neuronal impulse count were increased with increase in stimulus duration. Following spinalization, the spinal neuronal responses were stronger and the stimulus duration-dependent increase in the impulse count developed faster. Moreover, the peak frequency of spinal neuronal response increased significantly with prolongation of the heat stimuli after spinalization, but not in animals with an intact spinal cord. The results indicate that stimulus rise rate, stimulus duration, and the adapting temperature are important factors in determining the sensory and spinal neuronal responses to high-intensity heat stimuli. The changes in the total impulse counts evoked by varying supraliminal heat stimuli in spinal dorsal horn WDR neurons corresponded well with the changes in pain magnitude estimates in humans. Also, the changes in spinal neuronal response onset latencies were accompanied by corresponding changes in onset latencies of human pain reactions but not with pain magnitude estimates. The effect of spinalization indicated that descending pathways control not only the response magnitude in the spinal dorsal horn WDR neurons but also the temporal characteristics of the spinal neuronal response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050756
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  • 90
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    Light touch contribution to balance in normal bipedal stance (1999)
    Springer
    Experimental brain research 125 (1999), S. 521-524 
    Details
    ISSN: 1432-1106
    Keywords: Key words Light touch ; Sway ; Centre of pressure ; Hand force ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  It has previously been shown that light contact with the finger tip on a fixed surface reduces centre of pressure (CoP) fluctuations in the frontal plane when standing in an unstable posture with the feet in line (tandem Romberg stance). Positive cross-correlations between horizontal finger forces and CoP fluctuations with finger forces exhibiting a phase lead suggest the hand provides sensory input for postural stability. The present study investigates whether this is the case for normal posture. We report reduced CoP fluctuations in the sagittal plane when light touch is permitted during normal bipedal stance. Moreover, we find positive crosscorrelations between finger tip forces and CoP fluctuations which are of similar magnitude and phase lag to those observed in tandem Romberg stance. This shows the utility of hand touch input for regulation of normal upright posture as well as inherently unstable postures such as tandem Romberg.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050711
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  • 91
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    A systematic review of vinpocetine therapy in acute ischaemic stroke (1999)
    Springer
    European journal of clinical pharmacology 55 (1999), S. 349-352 
    Details
    ISSN: 1432-1041
    Keywords: Key words Ischaemic stroke ; Vinpocetine ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: To determine whether vinpocetine decreases short- and long-term case fatality and proportion of dependent survivors if administered within 2 weeks of stroke onset. Methods: All published and unpublished trials were attempted to be identified using the standard search strategy of the Cochrane Collaboration Stroke Review Group, using MEDLINE searches performed with all known manufacturer code names and trade names of vinpocetine and by contacting manufacturers of vinpocetine to give information of all randomised controlled trials on vinpocetine in stroke. Researchers who participated in trials on vinpocetine in Hungary were asked for further information. Only truly randomised, unconfounded clinical trials that compared the effect of vinpocetine to either placebo or another reference treatment for acute stroke where treatment started no later than 14 days after stroke onset were eligible for inclusion. Data synthesis and analysis was performed using the Cochrane Review Manager software (RevMan version 3.0). Results: Among the identified studies on vinpocetine in stroke, only one fulfilled the selection criteria for inclusion in the review. No death occurred in the study groups and no statistically significant difference was found in dependency between the treatment and the placebo groups. No adverse effects were reported. Conclusions: Based on only one small randomised controlled unconfounded study, presently there is not enough evidence to decide whether the administration of vinpocetine does or does not decrease case fatality and dependency in acute stroke.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050639
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  • 92
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    Directional effects of changes in muscle torques on initial path during simulated reaching movements (1999)
    Springer
    Experimental brain research 128 (1999), S. 353-368 
    Details
    ISSN: 1432-1106
    Keywords: Key words Multijoint arm ; Simulations ; Muscle torques ; Kinetics ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Adults are able to reach for an object for the first time with appropriate direction, speed, and accuracy. The rules by which the nervous system is able to set muscle activities to accomplish these outcomes are still debated and, indeed, the sensitivity of kinematics to variations in muscle torques is unknown for complex arm movements. As a result, this study used computer simulations to characterize the effects of change in muscle torque on initial hand path. The same change was applied to movements towards 12 directions in the horizontal plane, and changes were systematically manipulated such that: (1) torque amplitude was changed at one joint, (2) timing of torque was changed at one joint, and (3) amplitude and/or timing was changed at two joints. Results showed that simultaneous changes in torque amplitude at shoulder and elbow joints affected initial speed uniformly across direction. These results add to conclusions from previous experimental and modeling work that the simplest rule to produce a desired change in speed for any direction is to scale torque amplitude at both joints. In contrast, all simulations showed nonuniform effects on initial path direction. For some regions of the workspace, initial path direction was little affected by either a ±30% change in amplitude or a ±100-ms change in timing, whereas for other regions the same changes produced large effects on initial path direction. These findings suggest that the range of possible torque solutions to achieve a particular initial path direction varies within the workspace and, consequently, the requirements for an accurate initial path will vary within the workspace.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050855
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  • 93
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    The effect of target size and inertial load on the control of rapid aiming movements A test of speed-sensitive and speed-insensitive strategies (1999)
    Springer
    Experimental brain research 124 (1999), S. 151-158 
    Details
    ISSN: 1432-1106
    Keywords: Key words Aiming movements ; Target size ; Inertial load ; Strategies ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Two experiments are reported that investigated the effects of target size and inertial load on the control of rapid aiming movements. Based on kinematic profiles, movements were partitioned into their preprogrammed initial impulse- and feedback-based error correction phases. Electromyographic (EMG) rise rates were examined to investigate whether participants used a speed-sensitive or speed-insensitive control strategy. The results from both experiments showed that initial impulse velocity and EMG rise rates varied as a function of target size, i.e., a speed-sensitive strategy. This was the case whether participants were allowed to make error corrections to their movements (experiment 1) or were instructed to produce initial impulses that hit the target (experiment 2). Both experiments also showed that initial impulse velocity and endpoint variability were inversely related to inertial load. The results from experiment 2 indicated that, while the manipulation of inertial load had no effect on EMG rise rates for movements to a large target, EMG slopes were modulated between inertial load conditions when the target was small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050609
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  • 94
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    Antagonist motor responses correlate with kinesthetic illusions induced by tendon vibration (1999)
    Springer
    Experimental brain research 124 (1999), S. 342-350 
    Details
    ISSN: 1432-1106
    Keywords: Key words Vibration-induced kinesthetic illusions ; Antagonist vibratory response ; Motor units ; Wrist extensor muscles ; Human ; Microelectromyography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In humans, vibration applied to muscle tendons evokes illusory sensations of movement that are usually associated with an excitatory tonic response in muscles antagonistic to those vibrated (antagonist vibratory response or AVR). The aim of the present study was to investigate the neurophysiological mechanisms underlying such a motor response. For that purpose, we analyzed the relationships between the parameters of the tendon vibration (anatomical site and frequency) and those of the illusory movement perceived (direction and velocity), as well as the temporal, spatial, and quantitative characteristics of the corresponding AVRs (i.e., surface EMG, motor unit firing rates and activation latencies). Analogies were supposed between the characteristics of AVRs and voluntary contractions. The parameters of the AVR were thus compared with those of a voluntary contraction with similar temporal and mechanical characteristics, involving the same muscle groups as those activated by vibration. Wrist flexor muscles were vibrated either separately or simultaneously with wrist extensor muscles at frequencies between 30 and 80 Hz. The illusory movement sensations were quantified through contralateral hand-tracking movements. Electromyographic activity from the extensor carpi radialis muscles was recorded with surface and intramuscular microelectrodes. The results showed that vibration of the wrist flexor muscle group induced both a kinesthetic illusion of wrist extension and a motor response in the extensor carpi radialis muscles. Combined vibration of the two antagonistic muscle groups at the same frequency evoked neither kinesthetic illusion nor motor activity. In addition, vibrating the same two antagonistic muscle groups at different frequencies induced both a kinesthetic illusion and a motor response in the muscle vibrated at the lowest frequency. The surface EMG amplitude of the extensor carpi radialis as well as the motor unit activation latency and discharge frequency were clearly correlated to the parameters of the illusory movement evoked by the vibration. Indeed, the faster the illusory sensation of movement, the greater the surface EMG in these muscles during the AVRs and the sooner and the more intense the activation of the motor units of the wrist extensor muscles. Moreover, comparison of the AVR with voluntary contraction showed that all parameters were highly similar. Mainly slow motor units were recruited during the AVR and during its voluntary reproduction. That the AVR is observed only when a kinesthetic illusion is evoked, together with the similarities between voluntary contractions and AVRs, suggests that this vibration-induced motor response may result from a perceptual-to-motor transformation of proprioceptive information, rather than from spinal reflex mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050631
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    Effects of short-term adaptation of saccadic gaze amplitude on hand-pointing movements (1999)
    Springer
    Experimental brain research 124 (1999), S. 351-362 
    Details
    ISSN: 1432-1106
    Keywords: Key words Saccadic adaptation ; Gaze ; Short term adaptation ; Transfer to hand movements ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We investigated whether and how adaptive changes in saccadic amplitudes (short-term saccadic adaptation) modify hand movements when subjects are involved in a pointing task to visual targets without vision of the hand. An experiment consisted of the pre-adaptation test of hand pointing (placing the finger tip on a LED position), a period of adaptation, and a post-adaptation test of hand pointing. In a basic task (transfer paradigm A), the pre- and post-adaptation trials were performed without accompanying eye and head movements: in the double-step gaze adaptation task, subjects had to fixate a single, suddenly displaced visual target by moving eyes and head in a natural way. Two experimental sessions were run with the visual target jumping during the saccades, either backwards (from 30 to 20°, gaze saccade shortening) or onwards (30 to 40°, gaze saccade lengthening). Following gaze-shortening adaptation (level of adaptation 79±10%, mean and s.d.), we found a statistically significant shift (t-test, error level P〈0.05) in the final hand-movement points, possibly due to adaptation transfer, representing 15.2% of the respective gaze adaptation. After gaze-lengthening adaptation (level of adaptation 92±17%), a non-significant shift occurred in the opposite direction to that expected from adaptation transfer. The applied computations were also performed on some data of an earlier transfer paradigm (B, three target displacements at a time) with gain shortening. They revealed a significant transfer relative to the amount of adaptation of 18.5±17.5% (P〈0.05). In the coupling paradigm (C), we studied the influence of gaze saccade adaptation of hand-pointing movements with concomitant orienting gaze shifts. The adaptation levels achieved were 59±20% (shortening) and 61±27% (lengthening). Shifts in the final fingertip positions were congruent with internal coupling between gaze and hand, representing 53% of the respective gaze-amplitude changes in the shortening session and 6% in the lengthening session. With an adaptation transfer of less than 20% (paradigm A and B), we concluded that saccadic adaptation does not ”automatically” produce a functionally meaningful change in the skeleto-motor system controlling hand-pointing movements. In tasks with concomitant gaze saccades (coupling paradigm C), the modification of hand pointing by the adapted gaze comes out more clearly, but only in the shortening session.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050632
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    Complete suppression of voluntary motor drive during the silent period after transcranial magnetic stimulation (1999)
    Springer
    Experimental brain research 124 (1999), S. 447-454 
    Details
    ISSN: 1432-1106
    Keywords: Key words Transcranial magnetic stimulation ; Silent period ; Voluntary motor drive ; Motor threshold ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  To evaluate changes in the motor system during the silent period (SP) induced by transcranial magnetic stimulation (TMS) of the motor cortex, we investigated motor thresholds as parameters of the excitability of the cortico-muscular pathway after a suprathreshold conditioning stimulus in the abductor digiti minimi muscle (ADM) of normal humans. Since the unconditioned motor threshold was lower during voluntary tonic contraction than at rest (31.9±5.4% vs. 45.6±7.5%), it is suggested that the difference between active and resting motor threshold indicates the magnitude of the voluntary drive on the cortico-muscular pathway. Therefore, we compared conditioned resting and active motor threshold (cRMT and cAMT) during the SP. cRMT showed an intensity-dependent period of elevation of more than 200 ms in duration and approximately 17% of the maximum stimulator output above the unconditioned threshold, due to decreased excitability of the cortico-muscular pathway after the conditioning stimulus. Some 30–40 ms after the conditioning stimulus, cAMT approximated cRMT, indicating complete suppression of the voluntary motor drive. This suppression did not start directly after the conditioning stimulus since cAMT was still significantly lower than the cRMT within the first 30–40 ms. Threshold elevation was significantly longer than the SP (220±41 vs. 151±28 ms). Recovery of the voluntary motor drive started late in the SP and was nearly complete at the end of the SP, although thresholds were still significantly elevated. We conclude that the SP is largely due to a suppression of voluntary motor drive, while the threshold elevation is a different inhibitory phenomenon that is of less importance for the generation of the SP, at least in its late part. It is argued that the pathway of fast cortico-spinal fibers activated by TMS is partially different from the pathway involved in the maintenance of tonic voluntary muscle activation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050640
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    Recruitment and sequencing of different degrees of freedom during pointing movements involving the trunk in healthy and hemiparetic subjects (1999)
    Springer
    Experimental brain research 126 (1999), S. 55-67 
    Details
    ISSN: 1432-1106
    Keywords: Key words Motor control ; Multijoint movement ; Movement synergy ; Stroke ; Laterality ; Redundancy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Previous studies have shown that in neurologically normal subjects the addition of trunk motion during a reaching task does not affect the trajectory of the arm endpoint. Typically, the trunk begins to move before the onset and continues to move after the offset of the arm endpoint displacement. This observation shows that the potential contribution of the trunk to the motion of the arm endpoint toward a target is neutralized by appropriate compensatory movements of the shoulder and elbow. We tested the hypothesis that cortical and subcortical brain lesions may disrupt the timing of trunk and arm endpoint motion in hemiparetic subjects. Eight hemiparetic and six age-matched healthy subjects were seated on a stool with the right (dominant) arm in front of them on a table. The tip of the index finger (the arm endpoint) was initially at a distance of 20 cm from the midline of the chest. Wrist, elbow, and upper body positions as well as the coordinates of the arm endpoint were recorded with a three-dimensional motion analysis system (Optotrak) by infrared light-emitting diodes placed on the tip of the finger, the styloid process of the ulna, the lateral epicondyle of the humerus, the acromion processes bilaterally, and the sternal notch. In response to a preparatory signal, subjects lifted their arm 1–2 cm above the table and in response to a ”go” signal moved their endpoint as fast as possible from a near to a far target located at a distance of 35 cm and at a 45° angle to the right or left of the sagittal midline of the trunk. After a pause (200– 500 ms) they moved the endpoint back to the near target. Pointing movements were made without trunk motion (control trials) or with a sagittal motion of the trunk produced by means of a hip flexion or extension (test trials). In one set of test trials, subjects were required to move the trunk forward while moving the arm to the target (”in-phase movements”). In the other set, subjects were required to move the trunk backward when the arm moved to the far target (”out-of-phase movements”). Compared with healthy subjects, movements in hemiparetic subjects were segmented, slower, and characterized by a greater variability and by deflection of the trajectory from a straight line. In addition, there was a moderate increase in the errors in movement direction and extent. These deficits were similar in magnitude whether or not the trunk was involved. Although hemiparetic subjects were able to compensate the influence of the trunk motion on the movement of the arm endpoint, they accomplished this by making more segmented movements than healthy subjects. In addition, they were unable to stabilize the sequence of trunk and arm endpoint movements in a set of trials. It is concluded that recruitment and sequencing of different degrees of freedom may be impaired in this population of patients. This inability may partly be responsible for other deficits observed in hemiparetic subjects, including an increase in movement segmentation and duration. The lack of stereotypic movement sequencing may imply that these subjects had deficits in learning associated with short-term memory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050716
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  • 98
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    Effects of geometric joint constraints on the selection of final arm posture during reaching: a simulation study (1999)
    Springer
    Experimental brain research 126 (1999), S. 134-138 
    Details
    ISSN: 1432-1106
    Keywords: Key words Upper limb ; Posture ; Geometric constraints ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Significant debate exists regarding the neural strategies underlying the positioning and orienting of the hand during voluntary reaching movements of the human upper extremity. Some authors have suggested that positioning and orienting are controlled independently, while others have argued that a strong interdependence exists. In an effort to address this uncertainty, our study employed computer simulations to examine the impact of physiological limitations of joint rotation on the proposed independence of hand position and orientation. Specifically, we analyzed the effects of geometric constraints on final arm postures using a 7 degree-of-freedom model of the human arm. For 20 different hand configurations within the attainable workspace, we computed sets of achievable joint angles by applying inverse kinematics. From each set, we then calculated the locus of possible elbow positions for the particular final hand posture. When the joints were allowed 360° of rotation, the loci formed complete circles; however, when joint ranges were limited to physiological values, the extent of the loci decreased to an average arc angle of 54.6° (±27.9°). Imposition of joint limits also led to practically linear relationships between joint angles within a solution set. These theoretical results suggest a requirement for coordinated interaction between control of the joints associated with hand position and those involved with hand orientation in order to ensure attainable joint trajectories. Furthermore, it is conceivable that some of the correlations observed between joint angles in the course of natural reaching movements result from geometric constraints.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050723
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  • 99
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    Characterisation of paired-pulse transcranial magnetic stimulation conditions yielding intracortical inhibition or I-wave facilitation using a threshold-hunting paradigm (1999)
    Springer
    Experimental brain research 129 (1999), S. 317-324 
    Details
    ISSN: 1432-1106
    Keywords: Key words Paired-pulse transcranial magnetic stimulation ; Threshold hunting ; Intracortical inhibition ; Intracortical I-wave facilitation ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Short-interval, paired-pulse transcranial magnetic stimulation (TMS) is usually used to demonstrate intracortical inhibition. It was shown recently that with short-interval, paired-pulse TMS a facilitation – called intracortical I-wave facilitation – can also be demonstrated. It was the aim of this study to investigate which stimulus conditions lead to intracortical inhibition and what conditions yield an intracortical I-wave facilitation in a hand muscle of normal subjects. Paired-pulse TMS responses with an interstimulus interval of 1.2 ms were obtained from the abductor digiti minimi muscle of four normal subjects. A threshold-hunting paradigm with hunting through first or second stimulus variation was used to obtain a curve of threshold-pair strengths. All subjects showed two branches of stimulus interaction on this diagram. If the first stimulus of a threshold pair was below approximately 65% of resting motor threshold it modified the response primarily due to the second stimulus through intracortical inhibition. However, if the first stimulus of a threshold pair exceeded approximately 65% of resting motor threshold it became responsible for the spinal action-potential initiation. The subsequent second stimulus served as a ”booster” for the ongoing intracortical I-wave activity, making it impossible to observe the intracortical inhibition evoked by the first stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050901
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  • 100
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    Motion-responsive regions of the human brain (1999)
    Springer
    Experimental brain research 127 (1999), S. 355-370 
    Details
    ISSN: 1432-1106
    Keywords: Key words Visual cortex ; Motion ; Functional imaging ; Human ; Flicker
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Functional magnetic resonance imaging was used to map motion responsive regions of the human brain by contrasting passive viewing of moving and stationary randomly textured patterns. Regions were retained as motion responsive if they reached significance either in the group analysis or in the majority of hemispheres in single-subject analysis. They include well-known regions, such as V1, hMT/V5+, and hV3A, but also several occipito-temporal, occipito-parietal, parietal, and frontal regions. The time course of the activation was similar in most of these regions. Motion responses were nearly identical for binocular and monocular presentations. Flicker-induced-activation introduced a dichotomy amongst these motion responsive regions. Early occipital and occipito-temporal regions responded well to flicker, while flicker responses gradually vanished as one moved to occipito-parietal and then parietal regions. Finally, over a more than four-fold range, stimulus diameter had little effect on the motion activations, except in V1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050804
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