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Biomedical subjects

S C Müller

Publications and source records attributed to S C Müller.

At least 37 records · Page 2Linked to original sources
PubMed2004

[The modified ureterosigmoidostomy (Mainz pouch II) as a continent form of urinary diversion].

INTRODUCTION AND OBJECTIVES: The purpose of this study was to examine the outcome of the "Mainz Pouch II" urinary diversion at two different centers (the Klinik und Poliklinik für Urologie, Bonn and the Ospedale "San Salvadore", Pesaro, Italy) in terms of different techniques of ureteral implantation. MATERIALS AND METHODS: Between March 1995 and February 2003, the procedure was performed on 83 patients with 165 renal units (RU). Ureteral implantation with the Goodwin-Hohenfellner technique was performed in 57 RU, with the Abol-Enein modification in 23 RU and the Le-Duc procedure in 85 RU. Follow-up was available for 71 patients (85%) with a period of 1 to 82 months (mean 19.5 months, median 12 months). A non-validated questionnaire was used in the Bonn series to determine specific urinary diversion items. RESULTS: Early complications occurred in 12%, three requiring surgical intervention. Two patients died within the first 30 days after initial surgery. Pyelonephritis occurred in 12 RU (14% of the patients, 8.5% of the RU). Ureteral stenosis requiring reimplantation was found in two RU. The continence rate was 100% during daytime in the Bonn series; all but one patient had to get up for urination at night. A total of 63% of the patients were able to distinguish between stool and urine. CONCLUSION: Mainz pouch II is a quick, safe and easy to perform urinary diversion which serves as a satisfying alternative to other forms of continent diversion. Follow-up shows a low complication rate with good results in terms of continence; however, long term results have to be evaluated. There are no significant differences in complication rates for the different ureteral implantation techniques.

Colon, Sigmoid↗
PubMed2004

[Stress incontinence and mixed incontinence].

According to the new ICS classifications urinary incontinence is divided by symptomatic, clinical and urodynamic criteria. Urinary incontinence is a non life-threatening condition, which may affect life quality a lot. Stress incontinence may present alone or may occur as mixed incontinence. The understanding of pathophysiological interactions is important to perform adequate diagnostics and start appropriate therapy. The patients should be informed about the wide spectrum of different conservative and surgical treatment options, their results and typical complications. Further randomised trials are necessary for critical evaluation of each treatment option.

Clinical Trials as Topic↗
PubMed2004

Effect of a single excitation stimulus on photosynthetic activity and light-dependent pH banding in Chara cells.

Using pH microelectrodes and a Microscopy PAM (pulse-amplitude modulated) chlorophyll fluorometer, it is shown that a propagation of an action potential in Chara corallina leads to transient suppression of spatially periodic pH profiles along the illuminated cell. The suppression was manifested as a large pH decrease in the alkaline zones and a slight pH increase in the acid zones. The propagating action potential diminished the maximum yield of chlorophyll fluorescence (F(m)') in the alkaline cell regions, as well as the quantum yield of photosystem II photochemistry, without affecting F(m)' in the acid cell regions. The results indicate an interference of membrane excitation in the mechanisms responsible for pH banding patterns in Characean algae. Apparently, the electrical excitation of the plasma membrane in the alkaline cell regions initiates a pathway that can modulate membrane events at the thylakoid membrane.

Action Potentials↗
PubMed2004

Lack of ultrastructural detrusor changes following endoscopic injection of botulinum toxin type a in overactive neurogenic bladder.

INTRODUCTION: Endoscopical injections of Botulinum toxin type A into the detrusor muscle are gaining clinical acceptance in the treatment of neurogenic detrusor overactivity. Structural effects of Botulinum toxin type A are only known from studies on striated muscles, where a widespread nerve sprouting occurs temporarily. The aim of this study was to evaluate the ultrastructural effects of Botulinum toxin type A injections on the human detrusor. MATERIAL AND METHODS: 30 detrusor biopsies were obtained from 24 patients with neurogenic detrusor overactivity. Patients were divided into two groups: Group I included 13 biopsies from patients before the first Botulinum toxin type A injection. Group II included 6 biopsies from patients within 3 months after the first injection and 11 biopsies at the time of decreasing efficacy of Botulinum toxin type A. The biopsies were processed by standard procedure for detailed electron microscopic study and evaluated by 2 examiners without prior knowledge of clinical/urodynamic data. RESULTS: No statistically significant detrusor changes have been found concerning muscle cell fascicle structure (p = 0.445), width of intercellular space (p = 0.482) and number/kind of muscle cell junctions (p = 0.443). A median of 70% of intrinsic axon terminals presented with signs of degeneration in group I, a median of 66% in group II (p = 0.840). Out of 309 evaluated axon terminals in both groups, 1 sprouting axon was found in group I, 3 sprouting axons in group II (p = 0.864). Specimen from group I and group II showed only limited collagen deposits within the detrusor. No changes in the ultrastructure of the detrusor have been observed in those biopsies obtained before and after the Botulinum toxin type A injection of the same patient. CONCLUSION: This study verifies our earlier report of severe intrinsic axon degeneration in the detrusor of patients with neurogenic detrusor overactivity. It also shows nearly no structural differences of the detrusor before and after Botulinum toxin type A injections. Contrary to reports of striated muscle, axonal sprouting within the detrusor was very limited after Botulinum toxin type A injections indicating pathophysiologically different reactions to the toxin either between striated muscle and smooth muscle or between different treated diseases.

Adolescent↗
PubMed2004

Increased expression of connexin 43 in the overactive neurogenic detrusor.

PURPOSE: The cellular mechanisms involved in unstable uncontrolled detrusor contractions in the human bladder remain unknown. One hypothesis, based on electron microscopical observations and animal studies, is that gap junctions are present in the human detrusor and are increased in patients with detrusor overactivity. Thus intercellular electrical coupling between adjacent detrusor cells would be increased allowing electrical activity to spead more easily within the detrusor muscle mass and more readily generate significant contractions. The aim of this study was to prove this hypothesis. MATERIAL AND METHODS: Detrusor biopsies have been obtained from videourodynamically evaluated patients with neurogenic detrusor overactivity (NDO) (n = 19) [group I] and from patients with stress urinary incontinence (SUI) with stable, non-obstructed detrusors (n = 5) [group II] serving as controls. Specimens were fixed, paraffin embedded, sectioned, stained with a monoclonal connexin 43 antibody and evaluated by two blinded examiners using a semiquantitative scale. Connexin 43 mRNA levels were evaluated using quantitative RT-PCR with primers for connexin 43 and for 18S rRNA. The results were correlated with the patients' groups. RESULTS: Connexin 43 could be identified in cross sections of every detrusor biopsy. In all biopsies from patients with NDO a widespread presence of connexin 43 staining was observed, whereas only a limited presence of connexin 43 staining was observed in the specimen from patients with SUI. Connexin 43 mRNA levels within the detrusor were 3.7 fold higher in the NDO group than in the SUI group (p = 0.017). CONCLUSIONS: A limited amount of gap junctions seems to be present in every detrusor independently from its urodynamic stability or instability. But there is a significant increase in connexin 43 protein and RNA levels in patients with neurogenic detrusor overactivity underlining their role in intercellular electrical coupling.

Adolescent↗
PubMed2003

Destabilization of Turing structures by electric fields.

The dynamic behavior of hexagonal Turing patterns in the chlorine dioxide-iodine-malonic acid reaction was studied in a newly developed open reactor under the influence of externally applied weak directed current up to 17.5 mA. A transition from stationary hexagonal patterns to spots moving parallel to the direction of the applied electric field could be observed. The velocity of the drift increases monotonously with the applied current. Experimental results could be qualitatively reproduced in numerical simulations with a reaction-diffusion-advection model, based on a realistic kinetic mechanism.

Journal Article↗
PubMed2003

[Ureterocystoplasty: functional results and possible problem areas].

Surgical procedures such as ileal augmentation cystoplasties are often necessary in neurogenic low-compliance bladders. Whenever possible one should avoid using segments of the GI tract in the urinary tract and preferably use the patient's own ureter for augmentation cystoplasty. This procedure includes transperitoneal nephrectomy of a nonfunctioning kidney with preservation of the renal pelvis and the megaureter, followed by detubularization of the ureter and its integration into the opened urinary bladder. We performed this procedure on four patients, two boys and two girls (aged 6-13 years). In the long-term follow-up they all had good rehabilitation results for their lower urinary tracts with an increase of the storage volume and normalization of their reduced compliance. No deterioration of the remaining upper urinary tract was found. Complications such as partial ureteral necrosis have to be taken into consideration when the vascularization of the ureter is compromised, for example, by multiple prior antireflux procedures.

Adolescent↗
PubMed2003

Transitions from alkaline spots to regular bands during pH pattern formation at the plasmalemma of Chara cells.

A scanning pH-microprobe was used to study pH patterns near the surface of Chara corallina cells at various light intensities and during light-induced transitions from homogeneous pH distribution to alternating pH bands. In the irradiance (PAR) range 4-400 micromol quanta m(-2) s(-1), the sustained pH profiles consisted of alternating acid and alkaline bands with a characteristic length of 7-10 mm and pH shifts as large as 2-3 units. At lower irradiance, the number of alkaline bands decreased while the amplitude of remaining peaks stayed high. On cyclic changes in light intensity, a hysteresis of pH banding was observed: the pH bands tolerated low irradiance in weakening light, but higher irradiance was required for their emergence after dark adaptation of the cell. The pH profiles measured for different paths of electrode scanning suggest that the pH pattern at low light level represents patches coexisting with bands. The exposure of the cell to high-intensity light led to formation of radially symmetrical bands. Transformations of the pH pattern induced by lowering the light intensity were similar to those induced by transcellular electric current (1.5-3 microA). The data suggest that band formation at the plasmalemma of Chara cells proceeds through the initial appearance of multiple patches with a localized H(+)-transporting activity and subsequent spot rearrangements (fusion, deletions, widening), leading to establishment of alternating bands.

Adaptation, Physiological↗
PubMed2003

[Therapy of cryptorchidism. Viewpoints for optimizing fertility].

The pathophysiology of cryptorchidism--the most common anomaly of the urogenital tract--is still not well understood. Delayed treatment results in reduced fertility and even after correct therapy the risk of malignancy after puberty remains elevated. Intra-uterine maternal hCG stimulation and a postpartal GnRH rise in conjunction with a nor-mal hypothalamus-pituitary-gonadal-axis are essential for the normal development of the germ cells. Disturbances in these key-events of hormonal stimulation lead to a pre-pubertal hypogonadotropic hypogonadism with impaired fertility. Only the early beginning of hormonal therapy, best done sequentially (GnRH + hCG), can promote the physiologic descend and normal fertility. Surgery, even if performed early enough, has little impact on the physiology of germ cell development, cannot alter the risk of subsequent malignancy and improves only the cosmetic appearance. To reach optimal fertility each not descended testicle should be treated primarily using hormonal therapy.

Chorionic Gonadotropin↗
PubMed2003

[Bladder dysfunction due to rare neurological disorders].

Diseases or lesions of the central or peripheral nervous system involving the innervation of the lower urinary tract lead to neurogenic bladder dysfunction. Results are typical changes in storage and voiding function of the bladder according to pathophysiological and urodynamical criteria. In case of neurological disorders the neurological symptoms are not always the leading ones. The differential diagnosis of correlating bladder dysfunction is often difficult and special pathophysiological knowledge is necessary. Etiological factors are congenital, degenerative, vascular, inflammatory and immunological processes or tumour-specific changes of the nervous system. In many cases urodynamic evaluation and early interdisciplinary cooperation is necessary for special differentiation and diagnosis, especially of those diseases which rarely lead to initial bladder symptoms. The "nonneurogenic neurogenic bladder" or "Hinman-Syndrom" is well known in the literature but shouldn't be diagnosed until possible neurological reasons are excluded by modern diagnostic tools with newest imaging techniques.

Diagnosis, Differential↗
PubMed2003

Migraine aura dynamics after reverse retinotopic mapping of weak excitation waves in the primary visual cortex.

Akinematical model for excitable wave propagation is analyzed to describe the dynamics of a typical neurological symptom of migraine. The kinematical model equation is solved analytically for a linear dependency between front curvature and velocity. The resulting wave starts from an initial excitation and moves in the medium that represents the primary visual cortex. Due to very weak excitability the wave propagates only across a confined area and eventually disappears. This cortical excitation pattern is projected onto a visual hemifield by reverse retinotopic mapping. Weak excitability explains the confined appearance of aura symptoms in time and sensory space. The affected area in the visual field matches in growth and form the one reported by migraine sufferers. The results can be extended from visual to tactile and to other sensory symptoms. If the spatiotemporal pattern from our model can be matched in future investigations with those from introspectives, it would allow one to draw conclusions on topographic mapping of sensory input in human cortex.

Brain Mapping↗
PubMed2003

Extensive surgery in metastatic testicular cancer.

Surgery remains an important component in the multimodal treatment of patients with advanced testicular cancer. Recently, however, the indications for post-chemotherapy residual tumor resection have changed. Patients with advanced seminoma very rarely need surgical resection of the residual disease after standard chemotherapy. In contrast, patients with high stage non-seminomatous testis cancer must undergo post-chemotherapy surgery in most cases. Surgical resection in metastatic disease may also be necessary in patients with recurrent tumors, patients with persisting marker elevation during chemotherapy and patients with late relapses. Post-chemotherapy residual tumor resections, "redo"-retroperitoneal tumor operations and other salvage resections are often technically demanding procedures with unusual surgical approaches that require individualized perioperative planning in order to reduce morbidity. This paper summarizes the current indications for post-chemotherapy surgery and discusses various surgical approaches and techniques, perioperative management recommendations, as well as complications of these extensive resection procedures.

Adult↗
PubMed2003

[Medizip surgical zipper: a new form of non-invasive wound closure with a surgical zipper].

PURPOSE: We describe the use of a new, non-invasive skin closure system (Medizip, Nycomed Pharma GmbH, Ismaning, Germany) in urological procedures. MATERIALS AND METHODS: Between July and November 2002, 23 patients received non-invasive skin closure with a Medizip surgical zipper after urological procedures (13 radical prostatectomies, 3 suprapubic prostatic enucleations, 3 ablatio testis and 1 lumbal nephrectomy). Wound inspection was performed on day 3, day 8 and 6 weeks postoperatively. RESULTS: No wound complication such as infection or separation occurred. Wound dehiscence was seen in two patients (2 and 3mm). The zipper was removed routinely on day 8 after surgery. Of the 23 patients, 22 were pleased with the cosmetic results and rated the Medizip agreeable to wear. CONCLUSIONS: The Medizip surgical zipper is a safe, cosmetically satisfactory, cost-effective and time-sparing alternative to conventional suture material for skin closure.

Humans↗
PubMed2003

[A new method for the evaluation of stone fragmentation after ESWL].

INTRODUCTION: Efficacy of ESWL treatment can be evaluated by determining the number and size of urinary stone fragments. However, the available methods for classification of stone fragments are inaccurate. Therefore, a method for semi-automatic determination of fragment size and number after ESWL was developed. METHODS: Artificial struvite stones (BON[N]-STONES) were disintegrated with a lithotriptor (Siemens, Lithostar plus) by application of 50 and 200 shock waves at 19 kV. The stone fragments were collected and pre-sorted on cascade sieves. Pictures taken of the fractions were digitalized and the images optimized in edge sharpness, contrast, and colour depth using an image processing software. Finally, the pixel number of each fragment was determined and the real area was calculated. Fragment size and volume were then depicted by frequency of occurrence in a histogram. RESULTS: Fragments with a diameter ranging from 0.3 - 5 mm could be determined by the system described. About 2,000 - 3,600 fragments were generated in this size range from the artificial struvite stones. With low shock-wave application, a considerable number of fragments larger than 2 mm could be observed. By increasing the impact to 200, more than 90 % of the stone volume was found in fragments smaller than 2 mm (previously 50 %). CONCLUSION: The system described enables a qualitative and quantitative description of stone fragmentation after ESWL not achieved thus far.

Humans↗
PubMed2002

Excitation fronts in a spatially modulated light-sensitive Belousov-Zhabotinsky system.

The evolution of excitation wave fronts in a spatially modulated light-sensitive Belousov-Zhabotinsky system is investigated experimentally and theoretically. The excitation wave propagates in a thin, quasi-two-dimensional reaction layer, which is illuminated through a periodical gray level mask. The light-induced differences in excitability and velocity give rise to a temporal and spatial modulation of the initially flat fronts. The experimental front evolution is described in the framework of a kinematical theory as developed earlier for nonuniformly curved systems.

Journal Article↗
PubMed2002

Gemcitabine monotherapy as second-line treatment in cisplatin-refractory transitional cell carcinoma - prognostic factors for response and improvement of quality of life.

OBJECTIVES: i) To evaluate objective response, toxicity, and quality of life (QoL) of gemcitabine monotherapy as second-line treatment in patients with cisplatin-refractory, metastatic transitional cell carcinoma (TCC). ii) To assess prognostic parameters for response to treatment and for improvement of QoL parameters. PATIENTS AND METHODS: 30 patients were prospectively enrolled in this open-label, nonrandomized multicenter phase II trial. Patients received up to 6 courses of gemcitabine monotherapy (1,250 mg/m(2) on day 1 and 8 of a 21-day course). 28 of 30 patients were available for response evaluation. RESULTS: Objective response (OR) was seen in 3/28 (11%) of patients (2 complete remissions, 1 partial remission). The mean time to progression (TTP) was 4.9 +/- 3.5 months and mean disease-specific survival time was 8.7 +/- 4.7 months. 13 of 28 patients did not progress (OR + 10 stable diseases), and TTP (8.0 +/- 2.7 months, p < 0.001) as well as survival time (10.2 +/- 3.8 months, p < 0.05) differed significantly from those who showed progressive disease within 18 weeks of treatment. Pain values significantly improved in the group of responders from 4.3 +/- 1.9 to 5.8 +/- 1.3 points (p < 0.05). Response to cisplatin pretreatment was the best prognosticator for the response to gemcitabine. CONCLUSIONS: Gemcitabine monotherapy as second-line treatment is justified in patients with metastatic TCC who are refractory to cisplatin treatment. Patients with initially OR to cisplatin benefit most from second-line treatment. QoL remains stable during treatment, and pain improves especially in patients with bone metastases.

Carcinoma, Transitional Cell↗
PubMed2002

Chemolitholysis and lithotripsy of infectious urinary stones - an in vitro study.

OBJECTIVES: This study was performed to look for an improvement of therapeutic strategies with regard to the treatment of infectious urinary stones using artificial stones made of struvite and apatite ('Bon(n) stones') which are comparable to their natural counterparts. MATERIALS AND METHODS: Using an experimental arrangement simulating the physiological conditions in the upper urinary tract, the efficacy of artificial urine (pH 5.7), Suby G solution (pH 3.6), mixtures of artificial urine with Suby G (pH 3.9 and pH 4.1) in dissolving artificial struvite and apatite stones (Bon(n) stones) was investigated. The dissolution of natural infectious urinary stones was also measured. Additionally, investigations on shock-wave lithotripsy (SWL) combined with initial chemolytic treatment of the stones were performed. RESULTS: The efficacy of Suby G solution in dissolving artificial stones was demonstrated. Direct comparison of chemolysis of natural and artificial stones showed no statistical difference between infectious urinary stones and Bon(n) stones of the same material. The investigations on SWL showed a significant improvement on stone comminution, especially of artificial apatite stones after initial chemolytic treatment with Suby G. CONCLUSION: New basics to improve dissolution of infectious urinary stones have been developed by performing standardized in vitro investigations. Local chemolysis with Suby G is an effective tool in the treatment of infectious stone disease. SWL can be improved by varying the physical properties of infectious stones through initial treatment with Suby G solution.

Apatites↗