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Hubert John

Publications and source records attributed to Hubert John.

14 recordsLinked to original sources
PubMed2006

Optimization of the artificial urinary sphincter: modelling and experimental validation.

The artificial urinary sphincter should be long enough to prevent strangulation effects of the urethral tissue and short enough to avoid the improper dissection of the surrounding tissue. To optimize the sphincter length, the empirical three-parameter urethra compression model is proposed based on the mechanical properties of the urethra: wall pressure, tissue response rim force and sphincter periphery length. In vitro studies using explanted animal or human urethras and different artificial sphincters demonstrate its applicability. The pressure of the sphincter to close the urethra is shown to be a linear function of the bladder pressure. The force to close the urethra depends on the sphincter length linearly. Human urethras display the same dependences as the urethras of pig, dog, sheep and calf. Quantitatively, however, sow urethras resemble best the human ones. For the human urethras, the mean wall pressure corresponds to (-12.6 +/- 0.9) cmH2O and (-8.7 +/- 1.1) cmH2O, the rim length to (3.0 +/- 0.3) mm and (5.1 +/- 0.3) mm and the rim force to (60 +/- 20) mN and (100 +/- 20) mN for urethra opening and closing, respectively. Assuming an intravesical pressure of 40 cmH2O, and an external pressure on the urethra of 60 cmH2O, the model leads to the optimized sphincter length of (17.3 +/- 3.8) mm.

Adult↗
PubMed2005

Laparoscopic radical prostatectomy--the experience of the German Laparoscopic Working Group.

PURPOSE: To present the current status of laparoscopic radical prostatectomy (LRP) in Germany, Austria and Switzerland with respect to transferability, learning curve, and outcome. MATERIAL AND METHODS: The data of 5824 patients who underwent LRP in 18 centers by 50 urologists from March 1999 to August 2004 were analyzed retrospectively. Three centers performed more than 500, and six more than 250 cases. A transperitoneal descending technique with was used in 2701, a transperitoneal ascending in 1234, an extraperitoneal descending in 1814, and an extraperitoneal ascending modification in 75 cases. Specimen showed pT2 in 3535, pT3a in 1555, pT3b in 623, and pT4 in 111 cases. RESULTS: Mean operating time averaged 211 (131-292) minutes, with shorter duration of the extraperitoneal descending technique. Conversion to open surgery averaged 2.4 (0-14.1) %. Re-intervention rate amounted to 2.7 (0.3-7.7) %. Complication rate averaged 8.9 (1.8-10.8) % including bleeding (0.3-2.5%) and rectal lesion (1.5-2.5%). The rate of positive margins was 10.6 (3.2-18) % for pT2- and 32.7 (20-38.5) % for pT3a-tumors Continence after 12 months was 84.9 (72-94) %. Data about potency (7 centers) revealed 52.5 (35-67) % full erections following bilateral nerve preservation. 5 year-PSA recurrence rate (3 centers) was 8.6 (4-15.3) % for pT2-tumors and 17.5 (15-20.6) % for pT3a-stages. CONCLUSIONS: The results confirm the efficacy of the training program with safe transfer of LRP (i.e. low complication rate), however including all known problems of a retrospective study.

Adult↗
PubMed2005

Local anesthesia for transurethral manipulations: is a transrectal periprostatic nerve block effective?

Periprostatic nerve block has been reported to be an effective form of anesthesia for prostatic surgery. Recent studies have shown the simplicity and the efficacy of a transrectal approach for periprostatic nerve block. The goal of our study was to evaluate the effect of a transrectal periprostatic nerve block on the discomfort associated with rigid cystoscopy. A total of 73 patients underwent cystoscopy. Group 1 (n = 39) received a transrectal periprostatic lidocaine infiltration prior to the cystoscopy. Group 2 (n = 34) underwent cystoscopy alone. The pain that patients experienced during cystoscopy was assessed on a visual analog scale. The patients in the two groups were very similar in regard to age and size of the prostate. The mean pain score was 3.4 in group 1 and 3.9 in group 2. This difference was not statistically significant. We conclude that nerve block does not seem to reduce the pain associated with transurethral manipulations.

Aged↗
PubMed2005

Fluorocholine PET/CT in patients with prostate cancer: initial experience.

Institutional review board approval and written informed consent were obtained. Patients with newly diagnosed prostate cancer and patients suspected of having recurrent prostate cancer were prospectively evaluated with fluorine 18 fluorocholine (FCH) combined in-line positron emission tomography (PET) and computed tomography (CT). In 19 patients (mean age, 67 years +/- 8; range, 57-85 years), standardized uptake values of FCH in 17 different tissues were determined by using volumes of interest. In nine patients evaluated at initial staging, histologic findings of the resected prostate were compared to FCH uptake. Only small variations of physiologic tracer accumulation were measured in all organs but the kidneys. Differentiation of benign hyperplasia from cancerous prostate lesions was not possible with FCH PET/CT. However, in patients with recurrent prostate cancer, FCH PET/CT is a promising imaging modality for detecting local recurrence and lymph node metastases.

Adenocarcinoma↗
PubMed2005

Bilateral perirenal lymphangioma: a conservative approach.

The lymphangioma is a well-recognized benign tumor most frequently encountered in infancy and childhood. The kidneys are rarely involved. Despite its benign nature, most of the patients were treated by partial or radical nephrectomy. We describe a case of bilateral perirenal lymphangioma in a 33-year-old man for whom we chose a conservative approach.

Adult↗
PubMed2004

Bulbourethral composite suspension:: a new operative technique for post-prostatectomy incontinence.

PURPOSE: A new bulbourethral sling procedure is proposed for patients with post-radical prostatectomy incontinence. MATERIAL AND METHODS: Bulbourethral composite suspension was performed in 16 consecutive patients, of whom 6 (38%) had severe stress incontinence and depended on a condom urinal catheter. Urinary stress incontinence was assessed preoperatively by a modified pad test, urethrocystoscopy and urodynamic evaluation. The procedure was performed with a longitudinal perineal and a transverse suprapubic incision with the patient under regional anesthesia. We placed a porcine dermis for urethral protection and a polypropylene retropubic sling, which was tied suprapubically with the patient coughing and during retrograde urethral closure pressure monitoring at 60 cm H2O. RESULTS: Preoperative evaluation excluded detrusor instability and urethral stricture. The polypropylene band was placed without neurogenic or vascular complications. All patients had primary wound healing. Patients reported only minimal postoperative pain. Clinical followup was performed a median of 14 months postoperatively (range 6 to 32). Of the 16 patients 11 (69%) were completely dry and 1 (6%) reported improved continence, while 4 (25%) had no benefit, including 2 who underwent an artificial sphincter procedure. Preoperative mean daily pad use decreased from 7 (range 2 to 12) to 1 (range 0 to 10) postoperatively (p = 0.0004) and postoperative quality of life improved significantly (p <0.0001). CONCLUSIONS: Bulbourethral composite suspension is a new, efficient operative sling technique in patients with severe post-prostatectomy stress urinary continence. Because morbidity and complications are low, this new technique may become an alternative to artificial urinary sphincter implantation. Long-term observation of urethral and detrusor function is necessary to elucidate the specific contribution of bulbourethral composite suspension in restoring urinary continence after radical prostatectomy.

Aged↗
PubMed2003

Impact of prostatitis NIH IIIB (prostatodynia) on ejaculate parameters.

OBJECTIVES: Prostatitis NIH IIIB is defined by chronic pelvic pain without evidence of inflammation in prostate secretions or ejaculate. The relations between chronic prostatitis and fertility are discussed controversially. In this context, we analysed fertility data of a well defined collective of patients with prostatitis NIH IIIB. METHODS: We analysed prospective fertility data of a group of 30 patients with chronic prostatitis NIH IIIB and compared these data with the duration of symptoms as well as with an age-matched control group. RESULTS: The prostatitis group and the control group differed significantly in terms of ejaculate volume, motility and fructose concentration. The remaining parameters did not differ significantly. An azoospermia was present in 3 patients of the prostatitis group versus none of the control group. The duration of symptoms did not correlate with the sperm parameters (sperm density, motility and morphology). CONCLUSIONS: Patients with prostatitis NIH IIIB have changes in their ejaculate with a reduction of motility and a reduced fructose concentration. This supports a somatic aetiology of the chronic pelvic pain syndrome.

Adult↗
PubMed2003

Evidence of gap junctions in the stable nonobstructed human bladder.

PURPOSE: Gap junctions are thought to synchronize muscle cell actions by promoting intercellular communications. Since it is still a matter of debate whether smooth muscle cells in the bladder are electrically coupled, we investigated the occurrence of gap junctions and the gap junction forming protein connexin 45 in normal human detrusor. MATERIALS AND METHODS: Detrusor smooth muscle was obtained during radical cystectomy in 6 patients. For transmission electron microscopy studies samples were high pressure frozen and cryo-fixed. Additional frozen samples were processed for freeze fracture/freeze fracture immunolabeling analyses or for reverse transcriptase-polymerase chain reaction using primers for connexin 45. Furthermore, a set of samples was fixed with Bouin's solution, embedded in paraffin and used for immunohistochemistry with a polyclonal antibody against connexin 45 as well as for in situ hybridization studies with digoxigenin labeled connexin 45 riboprobes. RESULTS: Ultrastructural and freeze fracture studies showed gap junctions at detrusor smooth muscle cells. However, these gap junctions appeared to be small and irregularly shaped. Reverse transcriptase-polymerase chain reaction and in situ hybridization showed that connexin 45 mRNA was expressed in the detrusor muscularis. Furthermore, we detected prominent connexin 45 immunoreactions at detrusor smooth muscle cells. Freeze fracture immunolabeling techniques revealed connexin 45 signals at small gap junctional plaques. CONCLUSIONS: To our knowledge this study is the first to provide morphological, molecular biological and immunohistochemical evidence that smooth muscle cells of stable human detrusor are electrically coupled through gap junctions. These results may contribute to new concepts in the understanding of bladder physiology.

Aged↗
PubMed2003

A new high frequency electrostimulation device to treat chronic prostatitis.

PURPOSE: We prospectively observed a possible benefit from urethro-anal high frequency electrostimulation in patients with noninflammatory chronic pelvic pain syndrome (Cat IIIB CPPS) as a new treatment option. MATERIALS AND METHODS: A total of 88 patients with a referral diagnosis of chronic prostatitis underwent fractionated urinary cultures, including expressed prostate secretion and ejaculate analysis twice. Of this group 14 men with Cat IIIB CPPS elected electrostimulation. A urethro-anal stimulation device was applied twice weekly for 30 minutes during 5 weeks at a defined voltage of 6 V, a defined frequency of between 450 and 500 Hz, and a variable self-regulated current of between 1 and 10 mA. National Institutes of Health prostatitis symptom score and quality of life index were determined before and after the treatment. RESULTS: All patients tolerated stimulation and completed the treatment course. No urethral or anal complications occurred. Generally, the patients reported a distinct perineal feeling and the pain syndrome improved in 83%. The mean total National Institutes of Health prostatitis symptom score significantly decreased from 29 (range 20 to 37) to 14 (range 8 to 24) points (p = 0.002). Mean pain decreased from 15 (range 12 to 20) to 7 (range 4 to 13) points (p = 0.002). Micturition complaints decreased from 2.5 (range 0 to 9) to 1 (range 0 to 8) points (p = 0.007) and quality of life improved from 9.5 (range 8 to 12) to 5.5 (range 3 to 10) (p = 0.003). CONCLUSIONS: To date the new high frequency urethro-anal afferent electrostimulation device seems to have an important benefit in patients with Cat IIIB CPPS. The device is technically simple and it can be self-administered. Therefore, it may become a new ambulatory treatment option for patients with chronic pelvic pain syndrome.

Adult↗
PubMed2002

Occurrence and localization of uroguanylin in the aging human prostate.

Uroguanylin, a peptide hormone highly expressed in the gastrointestinal tract, is implicated in the regulation of epithelial salt and water transport processes. Since little is known about a possible role of uroguanylin in the reproductive system, we investigated for the first time the occurrence of this peptide in the human prostate using specimens of benign prostatic hyperplasia. Northern blot analyses detected a single uroguanylin transcript of approximately 600 bp in prostate RNA. The uroguanylin expression was further investigated by reverse transcriptase polymerase chain reaction of prostate RNA with uroguanylin-specific primers. Sequencing of the fragments obtained indicated the presence of a uroguanylin molecule with a sequence identical to its intestinal counterpart. Furthermore, in situ hybridization and immunohistochemistry revealed that uroguanylin mRNA and peptide are confined to epithelial cells of the prostate glands. Comparison with the distribution pattern of immunoreactivity for prostate-specific antigen (PSA) showed a high degree of colocalization of uroguanylin- and PSA-immunoreactive cells. In addition, by western blotting techniques we detected the presence of high molecular weight uroguanylin-immunoreactive material in prostatic fluid. In conclusion, our study indicates that the human prostate glands synthesize and secrete (pro-)uroguanylin. We hypothesize that this hormone may play a novel role in the male reproductive tract.

Aged↗
PubMed2002

Effect of radical prostatectomy on urethral blood flow.

OBJECTIVES: To study the effect of radical retropubic prostatectomy on urethral microcirculatory blood perfusion and urinary continence. Urinary stress incontinence after radical prostatectomy depends mainly on intrinsic distal sphincter integrity. METHODS: Urethral laser Doppler flowmetry was performed in 37 patients before and in 23 patients after (mean 15 months, range 2 to 23) radical prostatectomy for clinically localized prostate cancer. An endoscopic laser Doppler flow probe with a diameter of 1.8 mm was introduced through the working channel of a cystoscope and gently applied to the urethral mucosa at an intravesical pressure of 30 cm H(2)O. Blood flow was expressed simultaneously as a digital reading on the flowmeter (milliliters blood per minute per 100 gram tissue). The mean arterial blood pressure was monitored noninvasively. The Mann-Whitney U test was used for statistical analysis. RESULTS: Membranous urethral blood flow significantly decreased after radical prostatectomy from 18.8 +/- 7.9 mL/min per 100 gram tissue to 11.9 +/- 7.7 mL/min per 100 gram tissue (P = 0.04). However, the difference in the blood flow did not statistically differentiate continent patients from patients with urinary stress incontinence (P = 0.47). No correlation between urethral microcirculation and mean arterial blood pressure could be detected. CONCLUSIONS: Retropubic radical prostatectomy decreases membranous urethral microcirculation. However, this loss of vascularization does not have a major effect on distal sphincter function and continence after radical prostatectomy.

Humans↗