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  • 1
    Electronic Resource
    Electronic Resource
    A double pendulum plasma thrust balance and thrust measurement at a tandem mirror exhaust (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 4637-4643 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: For the purpose of measuring the plasma momentum flux in a plasma system, a highly sensitive and precision balance has been developed. It can measure a force, an impulse, or thrust as low as 0.1 mN free of mechanical noise, electrical and magnetic pickups. The double pendulum system consists of two parallel conducting plates. One or both of the plates can be suspended by needles. The needle suspended plate (or plates) can swing freely with negligible friction because of the sharp points of the needles. When one of the plates is impacted by an impulse it will swing relatively to the fixed plate or other movable plate. The capacitance between the plates changes as a result of such a motion. The change of capacitance as a function of time is recorded as an oscillating voltage signal. The amplitude of such a voltage signal is proportional to the impacting force or impulse. The proportional factor can be calibrated. The forces can thus be read out from the recorded value of the voltage. The equation of motion for the pendulum system has been solved analytically. The circuit equation for the electronic measurement system has been formulated and solved numerically. Using this balance the thrust at the exhaust of a Tandem Mirror plasma thruster has been measured. The analytical solution of the overall characteristics agrees greatly with the measurement. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146490
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  • 2
    Electronic Resource
    Electronic Resource
    Local therapy of rectal tumors (1996)
    Springer
    Diseases of the colon & rectum 39 (1996), S. 886-892 
    Details
    ISSN: 1530-0358
    Keywords: Transanal endoscopic microsurgery (TEM) ; Rectal tumors ; Local therapy ; Minimally invasive surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: The aim of the study is to outline the rising importance of local treatment of rectal tumors and a changing strategy in therapy of early rectal cancer. METHODS: As the surgical procedure, transanal endoscopic microsurgery was used. Indications for the local procedure were pT1 low-risk tumors and tumors of higher stages in patients with severe risk factors and of those who refused the operation according to oncologic guidelines. RESULTS: A total of 236 rectal adenomas and 98 carcinomas were locally excised using the transanal endoscopic microsurgery technique. Mortality rate was 0.3 percent, and rate of complications requiring surgical reintervention was 5.5 percent in adenomas and 8 percent in carcinomas. Final histology of removed carcinomas revealed 56 pT1, 27 pT2, and 15 pT3 stages. After an average follow-up time of 24 months, two recurrences were observed in the group of patients with pT1 low-risk carcinomas who only underwent local therapy. In both cases, a second intervention for cure was undertaken but for tumors in a late stage. CONCLUSIONS: In selected cases, local therapy of rectal carcinoma avoids high morbidity and mortality of the classical operation. Quality of life will be improved, especially if an artificial anus can be avoided. In case of recurrence, the chance of a secondary procedure for cure is not to be underestimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02053987
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  • 3
    Electronic Resource
    Electronic Resource
    Immunregulation der Wundheilung (1999)
    Springer
    Der Chirurg 70 (1999), S. 897-908 
    Details
    ISSN: 1433-0385
    Keywords: Key words: Wound healing ; Immunology ; Cytokines ; Growth factors ; Diabetes mellitus. ; Schlüsselwörter: Wundheilung ; Immunologie ; Cytokine ; Wachstumsfaktoren ; Diabetes mellitus.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Wundheilung ist eine reparative Immunantwort auf Gewebeläsion. Immunkompetente Zellen und ihre membrangebundenen und löslichen Mediatoren spielen eine zentrale Rolle bei der Regulation der Heilung. Der Reparationsprozeß vereint dabei die initiale Entzündungsreaktion mit der Synthese des neuen Gewebes. Ein Ungleichgewicht im Milieu stimulierender und hemmender Faktoren führt zu einer gestörten Heilung. Immunkompromittierende Faktoren unterschiedlicher Ursache hemmen die normale Immunreaktion und führen so zu einer verminderten Heilung. Aus der physiologischen Immunregulation der Wundheilung abgeleitete Therapieansätze zur Behandlung einer gestörten Wundheilung sind Gegenstand der aktuellen klinischen Forschung.
    Notes: Summary. Wound healing is a complex cascade of biochemical and cellular events designed to achieve restoration of tissue integrity following injury. Immune cells are critical for the outcome of healing. Much has been learned about the individual events that are involved in this process. Knowledge is scant, however, about the spatial and temporal interweaving of these events and how one step sets the stage for subsequent observed phenomena. Imbalance of stimulating and inhibiting factors causes failure of healing. Immunosuppressive states interfere with a normal immune response and impair wound repair. Clinically, new therapeutic approaches to modulate impaired healing are based on a knowledge of immune regulation of wound healing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001040050740
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  • 4
    Electronic Resource
    Electronic Resource
    Calcium- und Knochenstoffwechsel nach Gastrektomie (1997)
    Springer
    Der Chirurg 68 (1997), S. 784-788 
    Details
    ISSN: 1433-0385
    Keywords: Key words: Calcium metabolism ; Bone metabolism ; Gastrectomy ; Therapy ; Review. ; Schlüsselwörter: Calciumstoffwechsel ; Knochenstoffwechsel ; Gastrektomie ; Therapie ; Übersicht.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Nach Magenresektion oder Gastrektomie sind Störungen der Calcium- und Knochenstoffwechsels bekannt. Wahrscheinlich kommt es postoperativ aufgrund einer verminderten Calciumabsorption zu einem Abfall des Serumcalciums. Als Gegenregulation wird Parathormon ausgeschüttet und 1,25-(OH)2-Vitamin D neu gebildet, welche beide Calcium aus dem Knochen mobilisieren. Bei einem Teil der Patienten kommt es in der Folge zu einer Abnahme der Knochenmasse mit einem erhöhten Frakturrisiko. Bisher liegen keine anerkannten Behandlungsempfehlungen dieser Störungen vor, lediglich die Substitution von Vitamin D und Calcium wurde wiederholt empfohlen. Es wird eine Übersicht über die derzeitigen Vorstellungen zur Regulation des Calcium- und Knochenstoffwechsels nach Gastrektomie gegeben.
    Notes: Summary. Disturbances in calcium and bone metabolism after gastrectomy have long been recognized. It has been suggested that due to impaired calcium absorption after gastrectomy, serum calcium is decreased, being counterregulated by parathyroid hormone release and 1,25-(OH)2-vitamin D formation. Both parathyroid hormone and 1,25-(OH)2-vitamin D are known to release calcium from bone, resulting in bone mass loss and increased fracture risk in some of the gastrectomized patients. No therapy is currently generally agreed on, although supplementation of vitamin D and calcium has been suggested repeatedly. A review on the current understanding of calcium and bone metabolism after gastrectomy is given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001040050270
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  • 5
    Electronic Resource
    Electronic Resource
    Die chirurgische Wundsprechstunde Ein interdisziplinäres, diagnostisches und therapeutisches Konzept für chronische Wunden (1999)
    Springer
    Der Chirurg 70 (1999), S. 480-484 
    Details
    ISSN: 1433-0385
    Keywords: Key words: Chronic wounds ; Wound care ; Wound debridement. ; Schlüsselwörter: Chronische Wunden ; Wundbehandlung ; Wunddébridement.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Für Patienten mit chronischen Wunden fehlen in Deutschland standardisierte Therapiekonzepte in zentralen Behandlungszentren. Wir haben vor 6 Jahren ein solches Zentrum eingerichtet, wobei die lokalchirurgische Sanierung, feuchte Wundbehandlung und begleitende Therapie der Grunderkrankung im Mittelpunkt des standardisierten Behandlungskonzeptes steht. In dieser Wundsprechstunde wurde die lokale Wundbehandlung und die Koordination der einzelnen interdisziplinären Behandlungsschritte vorgenommen. Ein spezielles Wunddokumentationssystem diente zur Qualitätssicherung. Die Einbeziehung der Hausärzte und ambulanten Pflegedienste führte zu einer Erweiterung der Infrastruktur und ermöglichte eine kontrollierte Vernetzung der stationären und ambulanten Behandlung, wodurch 42 % der Patienten ausschließlich ambulant behandelt werden konnten. Nach den vorgestellten Daten konnte eine verbesserte Patientenversorgung erreicht werden: 69 % der Wunden, die zuvor 30 Monate erfolglos behandelt wurden, waren nach unserem Protokoll innerhalb von 12 Monaten abgeheilt. Die Analyse der Daten unterstreicht den Stellenwert der lokalchirurgischen Sanierung, wonach weder die Wundtiefe noch die Wundinfektion einen Einfluß auf die Heilungsraten hat, vermutlich durch die radikale Entfernung der Nekrosen. Nach den vorgestellten Daten rechtfertigen medizinische, soziale und wirtschaftliche Gründe die Einrichtung einer interdisziplinär organisierten Wundsprechstunde, die zwischenzeitlich in Deutschland Modellcharakter aufweist.
    Notes: Summary. In Germany there is no standardized wound care for patients with chronic wounds in specialized centers. We have established a wound care unit for the past 6 years. The principal concept of therapy was characterized by standardized local surgery, moist wound dressings and concomitant treatment of the underlying disease. We performed local therapy, coordinated the interdisciplinary treatment and developed a new wound documentation system for quality control. We established a close network, integrating general practitioners and home care organizations to realize a mainly outpatient treatment supported by short hospital therapy. Exclusive outpatient treatment was performed in 42 % of all patients. According to our prospective data, we achieved an improvement in wound care: 69 % of the wounds resistant to therapy for a mean of 30 months healed within 12 months after therapy according to our protocol. Our data strongly supported the importance of local surgery: neither wound depth nor wound infection had any influence on the healing rate, presumably due to radical excisional debridement of necrotic tissue. The presented data justify on medical and economic grounds the establishment of such wound care centers in Germany.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001040050676
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  • 6
    Electronic Resource
    Electronic Resource
    Determinants of a normal (versus impaired) oral glucose tolerance after combined pancreas-kidney transplantation in IDDM patients (1996)
    Springer
    Diabetologia 39 (1996), S. 462-468 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Pancreas transplantation ; insulin secretion ; pancreatic hormones ; oral glucose tolerance ; glucagon stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After successful pancreas transplantation, insulin-dependent diabetic patients are characterized by a normal or at worst impaired oral glucose tolerance (World Health Organisation criteria). It is not known which pathophysiological mechanisms cause the difference between normal and impaired oral glucose tolerance. Therefore, we studied 41 patients after successful combined pancreas-kidney transplantation using stimulation in the fasting state with oral glucose (75 g), intravenous glucose (0.33 g/kg) and glucagon bolus injection (1 mg i. v.). Glucose (glucose oxidase), insulin and C-peptide (immunoassay) were measured. Repeated-measures analysis of variance and multiple regression analysis were used to analyse the results which showed: 28 patients had a normal, and 13 patients had an impaired oral glucose tolerance. Impaired oral glucose tolerance was associated with a greatly reduced early phase insulin secretory response (insulin p 〈 0.0001; C-peptide p = 0.037). Age (p = 0.65), body mass index (p = 0.94), immunosuppressive therapy (cyclosporin A p = 0.84; predniso(lo)ne p = 0.91; azathioprine p = 0.60) and additional clinical parameters were not different. Reduced insulin secretory responses in patients with impaired oral glucose tolerance were also found with intravenous glucose or glucagon stimulations. Exocrine secretion (α-amylase in 24-h urine collections) also demonstrated reduced pancreatic function in these patients (–46 %; p = 0.04). Multiple regression analysis showed a significant correlation of 120-min glucose with ischaemia time (p = 0.003) and the number of HLA-DR mismatches (p = 0.026), but not with HLA-AB-mismatches (p = 0.084). In conclusion, the pathophysiological basis of impaired oral glucose tolerance after pancreas transplantation is a reduced insulin secretory capacity. Transplant damage is most likely caused by perioperative influences (ischaemia) and by the extent of rejection damage related, for example, to DR-mismatches. [Diabetologia (1996) 39: 462–468]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400678
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  • 7
    Electronic Resource
    Electronic Resource
    Determinants of a normal (versus impaired) oral glucose tolerance after combined pancreas-kidney transplantation in IDDM patients (1996)
    Springer
    Diabetologia 39 (1996), S. 462-468 
    Details
    ISSN: 1432-0428
    Keywords: Pancreas transplantation ; insulin secretion ; pancreatic hormones ; oral glucose tolerance ; glucagon stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After successful pancreas transplantation, insulin-dependent diabetic patients are characterized by a normal or at worst impaired oral glucose tolerance (World Health Organisation criteria). It is not known which pathophysiological mechanisms cause the difference between normal and impaired oral glucose tolerance. Therefore, we studied 41 patients after successful combined pancreas-kidney transplantation using stimulation in the fasting state with oral glucose (75 g), intravenous glucose (0.33 g/kg) and glucagon bolus injection (1 mg i.v.). Glucose (glucose oxidase), insulin and C-peptide (immunoassay) were measured. Repeated-measures analysis of variance and multiple regression analysis were used to analyse the results which showed: 28 patients had a normal, and 13 patients had an impaired oral glucose tolerance. Impaired oral glucose tolerance was associated with a greatly reduced early phase insulin secretory response (insulin p〈0.0001; C-peptide p=0.037). Age (p=0.65), body mass index (p=0.94), immunosuppressive therapy (cyclosporin A p=0.84; predniso(lo)ne p=0.91; azathioprine p=0.60) and additional clinical parameters were not different. Reduced insulin secretory responses in patients with impaired oral glucose tolerance were also found with intravenous glucose or glucagon stimulations. Exocrine secretion (α-amylase in 24-h urine collections) also demonstrated reduced pancreatic function in these patients (−46%; p=0.04). Multiple regression analysis showed a significant correlation of 120-min glucose with ischaemia time (p=0.003) and the number of HLA-DR mismatches (p=0.026), but not with HLA-AB-mismatches (p=0.084). In conclusion, the pathophysiological basis of impaired oral glucose tolerance after pancreas transplantation is a reduced insulin secretory capacity. Transplant damage is most likely caused by perioperative influences (ischaemia) and by the extent of rejection damage related, for example, to DR-mismatches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400678
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  • 8
    Electronic Resource
    Electronic Resource
    Introducing fluorine-18 fluoromisonidazole positron emission tomography for the localisation and quantification of pig liver hypoxia (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 95-109 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Liver cell hypoxia ; Nitroimidazole imaging ; Fluorine-18 fluoromisonidazole ; Positron emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Fluorine-18 labelled fluoromisonidazole ([18F]FMISO) has been shown to accumulate in hypoxic tissue in inverse proportion to tissue oxygenation. In order to evaluate the potential of [18F]FMISO as a possible positron emission tomography (PET) tracer for imaging of liver tissue hypoxia, we measured the [18F]FMISO uptake in 13 domestic pigs using dynamic PET scanning. Hypoxia was induced by segmental arterial hepatic occlusion. During the experimental procedure the fractional concentration of inspired oxygen (FiO2) was set to 0.67 in group A (n=6) and to 0.21 in group B (n=7) animals. Before and after arterial occlusion, the partial pressure of O2 in tissue (TPO2) and the arterial blood flow were determined in normal flow and flow-impaired liver segments. Standardised uptake values [SUV=kBq tissue (in g) / body weight (in kg) × injected dose (in kBq)] for [18F]FMISO were calculated from PET images obtained 3 hours after injection of about 10 MBq/kg body weight [18F]FMISO. Immediately before PET scanning, the mean arterial blood flow was significantly decreased in arterially occluded segments [group A: 0.41 (0.32–0.52); group B: 0.24 (0.16–0.33) ml min–1 g–1] compared with normal flow segments [group A: 1.05 (0.76–1.46); group B: 1.14 (0.83–1.57) ml min–1 g–1; geometric mean (95% confidence limits); P〈0.001 for both groups]. After PET scanning, the TPO2 of occluded segments (group A: 5.1 (4.1–6.4); group B: 3.5 (2.6–4.9) mmHg] was significantly decreased compared with normal flow segments [group A: 26.4 (21.2–33.0); group B: 18.2 (13.3–25.1) mmHg; P〈0.001 for both groups]. During the 3-h PET scan, the mean [18F]FMISO SUV determined in occluded segments increased significantly to 3.84 (3.12–4.72) in group A and 5.7 (4.71–6.9) in group B, while the SUV remained unchanged in corresponding normal liver tissue [group A: 1.4 (1.14–1.71); group B: 1.31 (1.09–1.57); P〈0.001 for both groups]. Regardless of ventilation conditions, a significant inverse exponential relationship was found between the TPO2 and the [18F]FMISO SUV (r 2=0.88, P〈0.001). Our results suggest that because tracer delivery to hypoxic tissues was maintained by the portal circulation, the [18F]FMISO accumulation in the liver was found to be directly related to the severity of tissue hypoxia. Thus, [18F]FMISO PET allows in vivo quantification of pig liver hypoxia using simple SUV analysis as long as tracer delivery is not critically reduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050365
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  • 9
    Electronic Resource
    Electronic Resource
    Allogenic bone graft viability after hip revision arthroplasty assessed by dynamic [18F]fluoride ion positron emission tomography (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 615-624 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Fluorine-18 ; Bone graft viability ; Hip revision arthroplasty ; Positron emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The biological fate of allogenic bone grafts in the acetabular cavity and their metabolic activity after acetabular augmentation is uncertain but is most important for the stability of hip implants after hip revision arthroplasty. The aim of this study was to quantify regional bone metabolism after hip replacement operations. Dynamic [18F]fluoride ion positron emission tomography (PET) was used to investigate the metabolic activity of acetabular allogenic bone grafts and genuine bone, either 3–6 weeks (short-term group, n = 9) or 5 months to 9 years (long-term group, n = 10) after hip revision arthroplasty. Applying a three-compartment model, the fluoride influx constant was calculated from individually fitted rate constants (K nlf) and by Patlak graphical analysis (K pat). The results were compared with genuine cancellous and cortical acetabular bone of contralateral hips without surgical trauma (n = 7). In genuine cortical bone, K nlf was significantly increased in short- (+140.9%) and long-term (+100.0%) groups compared with contralateral hips. Allogenic bone grafts were characterised by a significantly increased K nlf in the short-term group (+190.9%) compared with contralateral hips, but decreased almost to the baseline levels of contralateral hips (+45.5%) in the long-term. Values of K nlf cor-related with the rate constant K 1 in genuine (r = 0.89, P〈0.001) and allogenic bone regions (r = 0.79, P〈0.001), indicating a coupling between bone blood flow and bone metabolism in genuine bone as well as allogenic bone grafts. K pat values were highly correlated with K nlf measurements in all regions. In conclusion, [18F]fluoride ion PET revealed the presence of an increased host bone formation in allogenic bone grafts early after hip revision arthroplasty. In contrast to genuine cortical bone, allogenic bone graft metabolism decreased over time, possibly due to a reduced ability to respond to the same extent as genuine bone to elevated metabolic demands after surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050429
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  • 10
    Electronic Resource
    Electronic Resource
    Four-Channel Sleeve Catheter for Prolonged Measurement of Lower Esophageal Sphincter Pressure (1999)
    Springer
    Digestive diseases and sciences 44 (1999), S. 2456-2461 
    Details
    ISSN: 1573-2568
    Keywords: FOUR-CHANNEL SLEEVE CATHETER ; LOWER ESOPHAGEAL SPHINCTER PRESSURE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A sleeve catheter capable of monitoring thelower esophageal sphincter (LES) pressure in fourquadrants at right angels has been developed. Thepresent study used this four-quadrant sleeve catheter toassess radial asymmetry in LES in the supine, prone,and upright positions. The results in 37 normal subjectswere compared with those of a conventional side-holecatheter and a Dent sleeve catheter. In vitro studies showed that the response rate of eachradially oriented sleeve is comparable to the Dentsleeve. Mean pressures were not significantly differentbetween the three different types of catheter. The four-quadrant sleeve catheter consistentlydetected a higher LES pressure in the left posteriorposition, regardless of body position. The four quadrantsleeve catheter can be used to record LES pressure from four different quadrants of the LES forprolonged periods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026630904455
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