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  • 1
    ISSN: 1432-1173
    Keywords: Schlüsselwörter Dreidimensionale Rekonstruktion ; 3D ; Dermatohistopathologie ; Morphologie ; Keywords Three-dimensional reconstruction ; 3D ; Histology ; Dermatology ; 3d ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Background and Objective. The combination of digital image-analysis and computer-reconstruction of the three-dimensional architecture of the human skin can make this method usable on an acceptable time scale. Patients/Methods. We used biopsies of different diseases (malignant melanoma, lichen planus, psoriasis) and of normal skin. Immunhistologically stained sections were digitized and adjusted with respect to features of interest using the interlaced mode of an commercial image analysis system (Lucia G, Nikon GmbH, Düsseldorf). The sections have been segmented and the resulting three dimensional data sets were visualized on a UNIX based work station. Results. Three dimensional reconstruction provides a different view into the architecture of normal and diseased skin: for example, the course of the duct of sweat glands or the perforation of a malignant melanoma through the underlying infiltrate. Conclusions. A new rapid reconstruction method is presented producing multidimensional histological images of the skin within a few hours. This automation is of interest in basic research and should find its way into routine histological diagnosis.
    Notes: Zusammenfassung Hintergrund und Fragestellung. Die Kombination von computergestützter Bildanalyse und dreidimensionaler Rekonstruktion ermöglicht die wirklichkeitsgetreue Darstellung und Analyse der dreidimensionalen Architektur der menschlichen Haut bei akzeptablem Zeitaufwand. Patienten/Methodik. Verwendet wurden exemplarisch die im Rahmen der Routinediagnostik entnommenen Probebiopsien von 3 Patienten mit unterschiedlichen dermatologischen Krankheitsbildern (malignes Melanom, Lichen ruber, Psoriasis vulgaris) und Biopsien gesunder Haut. Die immunmarkierten, digitalisierten Serienschnitte wurden mithilfe des Bildanalysesystems Lucia (Nikon GmbH, Düsseldorf) im sog. Interlaced-Verfahren digitalisiert. Die dreidimensionalen Datensätze wurden segmentiert und an einer UNIX-Workstation visualisiert. Ergebnisse. Die dreidimensionale Rekonstruktion gibt Einblick in die Architektur der pathologischen und physiologischen Histologie, wie beispielsweise der charakteristischen Windung der Schweißdrüsenausführungsgänge unterhalb der Epidermis. In der Dermatoonkologie kann der punktuelle Durchbruch eines malignen Melanoms durch das unterliegende Infiltrat nachgewiesen werden. Schlussfolgerungen. Die Automatisierung zeigt neue Anwendungsmöglichkeiten der dreidimensionalen Rekonstruktion mittels digitalisierter Bilder mit einem hohen Maß an Objektivität bei standardisierten Bearbeitungs- und Färbeverfahren. Diese Darstellung ist ein hilfreicher Beitrag zur Diagnostik in der Dermatohistopathologie und Dermatohistologie.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0942-0940
    Keywords: Keywords: Eloquent cerebral areas; intraoperative identification; cortical cooling; intraoperative monitoring; somatosensory evoked potentials; electroencephalography.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary  Object. Function-preserving neurosurgery requires methods to identify functionally important CNS-areas intraoperatively. We investigated whether a combination of focal cerebro-cortical cooling and monitoring of somatosensory evoked potentials (SEP) is suited for this task, i.e. whether it is able to outline structures belonging to the somatosensory pathway.  Methods. In 17 Wistar rats the somatosensory cortex was focally cooled by 20°C below the initial tissue temperature for periods of five minutes. A cryoprobe with a tip diameter of 3 mm was used and tissue temperatures were measured below and at different distances to the cryoprobe. Tibial nerve evoked SEPs and EEG-spectra were recorded continuously.  Results. During cortical cooling the SEP-responses showed a marked delay and amplitude increase of the cortically generated components P13 and N18 and a small latency increase of the subcortically generated wave III. EEG-spectra were depressed mainly in the low frequency range. All cooling effects were reversible and in light- as well as electron-microscopic examinations no tissue damage was found.  Conclusions. Focal cooling of the cortex induces easily recognizable and reversible changes of the bio-electrical activity without causing any histological damage. Therefore the method seems suitable for identifying eloquent areas. It can be expected that clinical application of the cooling technique in combination with intraoperative electrophysiological monitoring will be helpful to further lower the risk of neurosurgical operations.  We propose that cooling mainly interferes with the synaptic transmission within the somatosensory cortex, because the observed amplitude increase can be explained by cold-induced depression of inhibitory cortical activity (disinhibition).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 131 (1994), S. 253-259 
    ISSN: 0942-0940
    Keywords: Hemispherectomy ; hydrocephalus ; ICP recordings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two cases of acute hydrocephalus 34 and 27 years after hemispherectomy are presented. Both were examined by intracranial pressure recordings and treated with shunting procedures. The recordings gave evidence of raised baseline values of intracranial pressure and showed pathological B-wave activity in over 80% of the recording time. The problem of free communication between the different compartments after hemispherectomy and different surgical approaches to solve the problem are discussed. Open surgery is not advocated.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Gene 90 (1990), S. 303-307 
    ISSN: 0378-1119
    Keywords: Recombinant DNA ; T-lymphocytes ; exon ; intron ; protein kinase ; λEMBL3 vector
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 1 (1994), S. 429-443 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The three-dimensional particle-in-cell code quicksilver [Seidel et al., Computational Physics, edited by A. Tenner (World Scientific, Singapore, 1991), p. 475] has been used to study applied-B ion diodes. The impedance behavior of the diode in these simulations is in good agreement with both analytic theory and experiments at peak power. The simulations also demonstrate the existence of electromagnetic instabilities which induce divergence in the ion beam. Early in time, there is an instability at high frequency relative to the ion transit time τi, and the resulting beam divergence is low. However, later in time, the system makes a transition to an instability with a frequency close to 1/τi, and the ion beam divergence rises to an unacceptably high value. The transition is associated with the build-up of electron space charge in the diode, and the resulting increase in the beam current density enhancement (J/JCL). Using different schemes to inhibit the electron evolution, the transition has both been postponed and permanently eliminated, resulting in Li+1 ion beams with a sustained divergence of ∼10 mrad at an energy of ∼10 MeV.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Tetrahedron 50 (1994), S. 7109-7114 
    ISSN: 0040-4020
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0040-4039
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Tetrahedron Letters 34 (1993), S. 4095-4096 
    ISSN: 0040-4039
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Hydrozephalus ; Hydrostatische Ventile ; Überdrainage ; Keywords Hydrocephalus ; Hydrostatic valves ; Overdrainage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Earlier design changes in hydrocephalus valves focusing on reducing overdrainage failed. Since the middle of the 1990s, hydrostatic valve constructions have been available which are claimed to solve this problem. The objective of this study was to evaluate the efficiency of these constructions. Clinical status and ventricular size were evaluated in 45 patients with chronic hydrocephalus before and 1, 6, and 26 weeks after operation. In 35 of these, a Miethke dual-switch valve was implanted (treatment group 1), and the others received a combination of a programmable Codman-Hakim valve and a Miethke shunt assistant as the hydrostatic element of the configuration (treatment group 2). A third group (n=6) had already been shunted but suffered from overdrainage symptoms which could not be overcome by conservative measures. In these cases, the only operative treatment was the implantation of a Miethke shunt assistant adjunctively to the existing valve. In groups 1 and 2, there was a significant permanent improvement in the clinical state in nearly 80% of cases and a moderate permanent improvement in about 10%. Mild clinical and radiological signs of overdrainage occurred in three patients during the first postoperative week but resolved without further operative measures within the next 5 weeks. Typically, the ventricular width was not or only marginally reduced in these 45 patients. In the patients treated for symptoms of overdrainage (group 3), complaints resolved within the first week after implantation of the shunt assistant. The study indicates that gravitational shunts may be very effective in preventing overdrainage in chronic hydrocephalus, and therefore these constructions could represent the gold standard in the treatment of chronic hydrocephalus.
    Notes: Zusammenfassung Frühere Designänderungen an den Hydrozephalusventilen, die darauf zielten, die gefürchtete Komplikation der Überdrainage zu verhindern, erwiesen sich als ungeeignet. Seit Mitte der 90er Jahre stehen neue Hydrozephalusventile – sog. hydrostatische Ventile –, die diese Problematik verringern sollen, zur Verfügung. Mit der vorliegenden Studie sollte untersucht werden, ob das Problem der Überdrainage durch diese neuen Ventilkonstruktionen zu verringern ist. Bei 45 Patienten mit chronischem Hydrozephalus wurde der klinische Status sowie die Ventrikelweite an Hand von CCT oder MRI vor und in festen Intervallen (1, 6, 26 Wochen) nach Shuntimplantation evaluiert. 35 Patienten erhielten ein Miethke Dual-Switch-Ventil (Therapiegruppe 1), die übrigen ein programmierbares Codmann-Hakim-Ventil mit einem Miethke-Shuntassistenten (Therapiegruppe 2) als Antigravitationseinheit. Eine 3. Therapiegruppe stellten Patienten (n=6) dar, die bereits seit längerem ein Ventil hatten und unter Überdrainagebeschwerden litten, die auf konservative Maßnahmen nicht ansprachen. Diesen Patienten wurde zum existierenden Ventil zusätzlich ein Miethke-Shuntassistent implantiert. Eine permanente deutliche Besserung trat bei Patienten in Behandlungsgruppe 1 und 2 in etwa 80% auf, etwas mehr als 10% zeigten eine mäßige Besserung. Klinische oder radiologische Zeichen der Überdrainage traten bei 3 Patienten in der 1. postoperativen Woche auf, verschwanden jedoch ohne jegliche operative Intervention bis zur nächsten Untersuchung. Die Ventrikelweite änderte sich bei den meisten Patienten nach der Shuntimplantation nicht oder marginal. Bei den Patienten der 3. Behandlungsgruppe verschwand innerhalb weniger Tage nach OP die präexistente Überdrainagesymptomatik. Die Studie zeigt, dass gravitationsgesteuerte Ventile die Überdrainagegefahr beim chronischen Hydrozephalus sehr effektiv verhindern.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Child's nervous system 14 (1998), S. 263-270 
    ISSN: 1433-0350
    Keywords: Key words Ependyma ; Hydrocephalus ; Congenital disease model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract H-Tx rats produce congenitally hydrocephalic offspring with varying severity of the condition. We used moderately hydrocephalic rats without evident clinical signs of hydrocephalus and normal controls from the same stock when they were at least 1.5 years old. Macroscopic anatomy was studied by MRI and in fixed brain slices and the ultrastructure of the ependyma, with REM. Apart from markedly stretched areas, where the ependyma was totally destroyed and subependymal structures directly exposed to the CSF, the density of ependymal microvilli and of tufts of cilia was reduced in proportion to the ventricular distension of a given area. A supraependymal “network”– never seen before in acute hydrocephalus – was found, whose purpose is probably to prevent further ventricular enlargement. We conclude that even in arrested hydrocephalus the ependymal sequelae of hydrocephalus are similar to those of the acute stage, illustrating the extremely limited potenctial for recovery, but the organism seems nevertheless to react with an internal stabilization of the ventricular system.
    Type of Medium: Electronic Resource
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