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  • 1
    ISSN: 1434-0879
    Keywords: Primary human renal cell carcinoma ; MTT staining assay ; Chemosensitivity testing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary MTT staining procedures have been used in chemosensitivity testing of established cell lines of human and other sources as well as of human leukaemias, but only limited information on its application in primary solid human tumors is presently available. We have evaluated MTT staining in primary human Renal Cell Carcinomas (RCCs), studied various factors interfering with the optimal use, and finally applied it in subsequent chemosensitivity testing. The method depends on the conversion of a water-soluble tetrazolium salt (MTT) to a purple colored formazan precipitate, a reaction effected by enzymes active only in living cells. Single cell suspensions of RCCs were obtained either by enzymatic dispersion or by mechanical dissagregation, filtered through gauze, and purified by Ficoll density centrifugation. Tests were carried out in 96-well microculture plates. 104 viable tumor cells per well at 4 h incubation time with 20 μg MTT/100 μl total medium volume yielded best results. Formazan crystals were dissolved with DMSO, and the plates were immediately measured on a microculture plate reader at 540 nm. Under these criteria, linearity of the system could be demonstrated. For chemosensitivity testing, cells were continuously exposed to a number of drugs prior to the MTT staining procedure. Reproducibility of results was assessed and confirmed by culturing RCCs in flasks additionally, resubmitting them after 1, 2, and 4 weeks to the MTT assay. We conclude that the semiautomated MTT assay offers a valid, rapid, reliable and simple method to determine the degree of chemoresistance in primary human RCCs.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-8726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In contrast to the extensive work on in vitro experiments for elucidation of the electrical properties of smooth musculature, the acquisition of knowledge on electrical signal behaviour from smooth-muscle cells in an in vivo situation remains very limited and rare. Smooth-muscle electromyographic recording from the smooth musculature of the genitourinary tract, in particular from the penile cavernous bodies and the urinary bladder, has recently become one of the most interesting issues in both impotence research as well as neurophysiological assessment of the urinary bladder. However, the inadequate available data on corpus cavernosum and EMG recordings remains controversial due to the significant discrepancy between basic physiology of the smooth musculature, technical prerequisites and the expected clinical impact from the smooth-muscle EMG of genitourinary organs. This article is an attempt to describe the fundamentals of smooth-muscle EMG signal behaviour and the technical prerequisites for data acquisition and analysis of electrical activity from smooth-muscle cells of the cavernous bodies and urinary bladder. A description is given of the technical aspects, including methodology and interpretation of the recorded data, and also of the possible interference by artefacts (endogeneous and exogeneous) that might limit the clinical relevance of this encouraging method. The advantages, pitfalls and limitations of online analogous data registration and the possibility of computer-assisted smooth-muscle electrical activity recording and analysis are demonstrated by basic in vivo studies on cavernous bodies and also the detrusor muscle.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-0879
    Keywords: Primary renal cell carcinoma ; MTT staining assay ; Chemoresistance ; Glutathione metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 59 cases of primary human renal cell carcinoma (RCC), cross-resistance and collateral susceptibility patterns were determined in an MTT microculture assay. Concomitantly, the glutathione (GSH) content and the enzymatic activity of γ-glutamyl transpeptidase (GGT) were measured as distinct resistance characteristics. Resistance or chemoresponse towards Vinca alkaloids and anthracyclines were found to be highly coincident, suggesting that the classical multidrug resistance mechanism is active in human RCC. Strong resistance to platinum complexes combined with relative sensitivity to bleomycin was significantly associated with elevated glutathione levels, providing evidence for another pathway instigating chemoresistance. In contrast, despite substantial enzymatic activity, GGT effects revealed no correlation to the chemoresistance pattern. This result implies that it is the GSH-linked binding and reduction potential rather than the GGT-associated transportation capacity that has an impact on the expression of chemoresistance in human RCC.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    World journal of urology 11 (1993), S. 26-30 
    ISSN: 1433-8726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary With extracorporeal shockwave lithotripsy (ESWL) stone fragmentation and the potential creation of residual stones has become an integral part of the treatment strategy. Therefore true recurrence, regrowth and pseudo-recurrence determine the rate of new stone formation. In unselected series the overall recurrence rate after ESWL varies between 6% after 1 year and 20% after 4 years. The comparison between the recurrence rate after ESWL and the natural recurrence rate reveals that the results of ESWL are better than expected. Lithotripsy has no special effect on true stone recurrence, and even pseudo-recurrence is of minor clinical significance.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1433-8726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using the new electromagnetic shockwave source of the Modulith SL 20 shockwave-induced renal trauma was evaluated by acute and chronic studies in the the canine kidney model. In a further study the electromagnetic shockwave source of the Lithostar Plus Overhead module was tested. Overall, 92 kidneys were exposed to shock waves coupled either by water bath (Modulith lab type) or by water cushion (Modulith prototype, Lithostar Overhead) under ultrasound localization. The generator voltage ranged between 11 and 21 kV, the number of impulses between 25 and 2500. After application of 1500/2500 shocks the extent of the renal lesion depended strictly on the applied generator voltage and was classified into 4 grades: Grade 0, no macroscopic trauma detectable (at 11–12 kV); grade 1, petechial medullary bleeding (at 13 kV); grade 2, cortical hematoma (at 14–16 kV); and grade 3, perirenal hematoma (17–20 kV). Whereas at low and medium energy levels the number of shocks played only a minor role, at maximal generator voltage (20 kV) even 25 impulses induced a grade 2 and 600 shocks a grade 3 lesion, emphasizing the importance of shockwave limitation in the upper energy range. In shockwave-induced renal trauma a vascular lesion was predominant and cellular necrosis was secondary. Coupling with a water cushion resulted in a 15%–20% decrease in the disintegrative and traumatic effect, which was compensated for by increasing the generator voltage by 2 kV. Long-term studies showed complete restitution following grade 1 and 2 trauma, whereas after a grade 3 lesion a small segmental and capsular fibrosis without hyperplasia of the juxtaglomerular apparatus was observed. Based on the characteristic ultrasound pattern found in the first study, the threshold for induction of grade 1 lesion was investigated. With both lithotripters a wide range for induction of a grade 1 lesion (Modulith 234–411, Lithostar Plus 220–740) and also a significant overlapping with grade 0 and 2 lesions was seen at low energy settings (levels 2–4). In contrast, the range of shocks (Modulith 96–150, Lithostar Plus 90–142) and overlapping was minimal when high energy was used (levels 7–9). Finally, the disintegration-trauma coefficient combining the results obtained in a standard stone model with those of the canine kidney model was introduced.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Urological research 18 (1990), S. S13 
    ISSN: 1434-0879
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1434-0879
    Keywords: Impotence ; Cholesterol ; Cavernous smooth muscle cells ; Thromboxane A2 receptor antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Our clinical data enabled us to demonstrate a correlation between impaired lipid metabolism and vasculogenic impotent men. Our aim was to evaluate the effect of an impaired lipid metabolism on the smooth muscle of the corpus cavernosum. A total of 16 rabbits were given a cholesterol-enriched diet for 3 months, and 8 of these received additional thromboxane A2 receptor antagonist; 10 other rabbits (control) were fed a normal diet. Subsequently, cavernous tissue biopsies were taken, and tissue lipid extractions and electron microscopic evaluation were made from 3 rabbits in each group. In the untreated high-cholesterol diet group, cholesterol levels reached approx. 2.1 μg/mg body weight compared with 1.07 μg/mg b.wt. in the thromboxane A2 receptor antagonist-treated group and elevated levels compared with control group. Similar results were found for the triglyceride and free fatty acid levels. Lecithin tissue levels in treated rabbits were distinctly elevated against those of other 2 groups. Ultramorphological examination of the control group disclosed normal smooth muscle cell (SMC) architecture with numerous sites of intercellular contacts. These findings contrasted with those of the high-cholesterol diet groups which showed significant SMC degeneration with loss of intercellular contacts. Our data imply that impaired lipid metabolism causes cavernous SMC degeneration which plays a major role in the pathogenesis of erectile dysfunction. The thromboxane A2 receptor antagonist seems to produce a protective metabolic effect on the erectile tissue which may have some consequences future treatment strategies.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Surgical endoscopy and other interventional techniques 7 (1993), S. 539-543 
    ISSN: 1432-2218
    Keywords: Laparoscopy ; Nephrectomy ; Laptent ; Open surgery ; Laparoscopic training
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In an effort to ensure proper training and to establish a routine amongst the surgical team right from the start, we began practicing laparoscopic techniques with the lap simulator. After having acquainted ourselves with the fundamentals of this minimal-invasive method, we applied our newfound experience to the animal model. Even though the subsequent studies with pigs were the best learning model in which to practice different surgical techniques — e.g., ureter clipping and renal vessel triple stapling with the Endo-GIA — various problems can arise in a true clinical situation since anatomical diversity exists between an animal and human situs. We found that a compromise could be reached by simulating laparoscopic conditions during open surgery without endangering the safety of the patient during any point of the operation. After open surgical exposure of the Gerota fascia was carried out, the operative site was completely covered with the Laptent. From this moment on, all operative steps were performed with laparoscopic instruments under continuous video monitoring. Our step-by-step training program has exposed the surgeon and OR staff to the complexity of this new surgical technique. The use of the Laptent has successfully bridged the gap between open and laparoscopic surgery. Most important of all, those surgical centers without access to extensive experimental studies will realize that Laptent-assisted surgery can be of benefit and facilitate the clinical introduction of this minimal-invasive method.
    Type of Medium: Electronic Resource
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