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Biomedical subjects

F Sommer

Publications and source records attributed to F Sommer.

At least 19 recordsLinked to original sources
PubMed2002

MAP kinase 1/2 (Erk 1/2) and serine/threonine specific protein kinase Akt/PKB expression and activity in the human corpus cavernosum.

Nitric oxide (NO) is an important mediator in the cavernosal smooth muscle relaxation that causes erections. The purpose of this study was to examine the existence, distribution and phosphorylation stage of two recently discovered key enzymes for NO regulation in human cavernosal tissue, the MAP Kinase 1/2 (Erk 1/2) and the serine/threonine specific protein kinase Akt/PKB. The expression of the enzymes was examined in corpus cavernosum specimens taken from both potent men and from patients with long-term impotence. There was a distinct difference in the activation stage of the MAP Kinase 1/2 (Erk 1/2) between endothelium and smooth muscle cells in potent patients. This finding gives evidence for a cell-type-specific regulation of the eNOS-dependent NO release. Furthermore, we found a higher basal level of active MAP Kinase 1/2 (Erk 1/2) in impotent patients. This finding gives the first evidence for an inhibitory influence of MAP Kinase 1/2 (Erk 1/2) on cavernosal eNOS activity.

Adolescent↗
PubMed2002

Epidemiology of Peyronie's disease.

Francois Gigot de la Peyronie, surgeon to Louis XV of France, has become synonymous with the rather enigmatic though not uncommon condition of Peyronie's disease (PD), a localized connective tissue disorder of the penile tunica albuginea. The true prevalence of Peyronie's disease is unknown. Therefore, we decided to perform an evaluation of existing epidemiological data. A prevalence rate of 3.2% was determined in male inhabitants of the greater Cologne area. This is much higher than revealed by the data reported up to now, thus rendering the accepted prevalence rates of 0.3% to 1% untenable. The actual prevalence of Peyronie's disease may be even higher, considering many patients' reluctance to report this embarrassing condition to their physicians. Along these lines, most clinicians note that the number of Peyronie's patients has increased since the advent of oral sildenafil. Comparably high prevalences are known for diabetes and urolithiasis, suggesting a greater frequency of this rare disease than formerly believed.

Age Distribution↗
PubMed2001

[Changes in penile blood flow during cycling--how does one prevent a decreased perfusion?].

BACKGROUND AND OBJECTIVES: An increased incidence of erectile dysfunction has been observed in cycling enthusiasts. Compression of the perineal region during cycling seems to cause decreased penile perfusion. The resulting hypoxaemia in the corpus cavernosum is associated with penile fibrosis, which leads in the long run to erectile dysfunction. This study set out to determine if cycling can cause changes in penile perfusion and, if so, what precautions can be taken to avoid any associated health hazards, including whether various saddle forms and designs might influence penile blood flow. COHORTS AND METHODS: In 100 healthy athletic men (aged 36 +/- 6.2 years) transcutaneous penile oxygen pressure (tpO (2)) at the glans penis was measured during cycling in different positions and with different types of saddle, using a modified Clark oxygen electrode. RESULTS: The penile blood supply decreased significantly during cycling in a seated position. Cycling in a standing or reclining position (on a reclining bicycle) did not lead to any decrease in penile blood flow. Saddle width was the most important factor for ensuring adequate penile perfusion while cycling in a seated position. CONCLUSION: This study demonstrates that changing from a seated to a standing position during cycling leads to a significant increase in penile perfusion. Therefore we suggest frequent changes from a seated to a standing position during cycling. Additionally we suggest taking sufficient breaks during prolonged and vigorous bike tours, in order to avoid any possible health hazards. Another, not yet widespread, alternative for avoiding a reduction in penile blood flow is cycling on a reclining bicycle.

Adult↗
PubMed2001

Lack of gastritis and of an adaptive immune response in interferon regulatory factor-1-deficient mice infected with Helicobacter pylori.

To study the role of T cell responses in Helicobacter pylori gastritis, C57BL/6 wild-type and interferon regulatory factor-1-deficient (IRF-1(-/-)) mice were infected with the mouse-adapted H. pylori Sydney strain. Mice lacking the transcription factor IRF-1 are defective in Th1 development and are therefore biased to mount a Th2-type response. After 4 months of infection, C57BL/6 mice developed severe gastritis and atrophy and mounted a Th1-type response towards H. pylori. The Th1 response was abrogated in IRF-1(-/-) mice. This defective Th1 response was associated with the total lack of gastritis and atrophy in IRF-1(-/-) mice despite severe colonization with H. pylori. In addition, IRF-1(-/-) mice did also not develop a Th2 reaction, since they failed to generate H. pylori-specific antibodies and to produce IL-4 in response to H. pylori antigens in vitro. Thus, the transcription factor IRF-1 is necessary for the development of gastritis and atrophy in H. pylori-infected wild-type mice, suggesting a role of Th1 cells in the pathogenesis of H. pylori-associated diseases.

Animals↗
PubMed2001

[Value of cryotherapy in localized prostatic carcinoma].

Prostate cancer represents the second most frequent malignant male disease in Germany. In the United States, approximately 35,000 men die from prostate cancer annually. The treatment of this disease is of particular interest to both clinical and investigative urologists. Radical prostatectomy and radiotherapy are established standard modalities in the treatment of organ-confined prostate cancer. As in other fields of urology, minimally invasive procedures have gained increased interest in urologic oncology. With cryoablation of the prostate, a minimally invasive therapy for prostate cancer has been available since 1989 and has been used and under investigation since then. Improvements in cryotechnique and progress in transrectal high-resolution ultrasonography enable the surgeon to achieve the curative target of thermoinduced destruction of the whole prostate gland. Control with thermocouples, ultrasound, and double-freeze techniques makes it possible to destroy the whole organ or the region of interest in high-risk patients or in patients who refuse to undergo open surgical procedures.

Aged↗
PubMed2001

Creative-dynamic image synthesis: a useful addition to the treatment options for impotence.

In contrast to the impressive advances made in somatic research on erectile dysfunction, psychogenic erectile dysfunction is usually treated as a monolithic block. In this study, we evaluated the erectogenic power of creative-dynamic image synthesis in men with psychogenic erectile dysfunction. Sixty-nine men with a mean age of 46 y, suffering from erectile dysfunction of no known organic cause, were entered in a placebo-controlled study in which the erectogenic power of imagination, yohimbine and a placebo were compared. There was a significant difference between the subjective results of creative-dynamic image synthesis (75% increase of potency) and those achieved through treatment with the drug yohimbine (55% increase in potency) and with a placebo (30% increase in potency). Creative-dynamic image synthesis is a potent initiator of erections in men with psychogenic erectile dysfunction, has no known side effects and is very cost-effective.

Adrenergic alpha-Antagonists↗
PubMed2001

The prevalence of Peyronie's disease: results of a large survey.

OBJECTIVES: To determine the prevalence of Peyronie's disease, a localized connective tissue disorder of the penile tunica albuginea, the symptoms of which include palpable plaque, painful erections and curvature of the penis, in a large sample of men in Germany. SUBJECTS AND METHODS: A standardized questionnaire was sent to 8000 male inhabitants (age range 30-80 years) of the greater Cologne area (approximately 1.5 million inhabitants). Three questions about the self-diagnosis of Peyronie's disease were previously assessed for validity on 158 healthy men and 24 patients with confirmed Peyronie's disease. To optimize the response rate, the questionnaire was mailed three times to all the men. RESULTS: The response rate after the third mailing was 55.4% (4432 men): 142 men (3.2%, mean age 57.4 years, SD 13.4) reported the new appearance of a palpable plaque which, from the previous validation, was the most sensitive question and the main symptom of the disease. In men aged 30-39 years only 1.5% reported localized penile induration, compared with 3.0% in those 40-49 and 50-59 years, 4.0% in those 60-69 years and 6.5% of those > 70 years old. Newly occurring angulation was reported by 119 of the 142 men (84%) and painful erection by 66 (46.5%). The combination of the three symptoms (plaque, deviation and painful erection) was reported by 46 of the 4432 respondents (1.04%), i.e. 32% of the 142 men with penile induration; 58 of the 142 men (41%) reported erectile dysfunction. CONCLUSIONS: This is the first large cross-sectional, community-based study to examine the prevalence of Peyronie's disease. Using previously validated questions the prevalence of Peyronie's disease in the sample was 3.2%; this is much higher than indicated in previous reports. A comparably high prevalence is reported for diabetes and urolithiasis, suggesting that this 'rare' disease is more widespread than previously thought.

Adult↗
PubMed2001

Impotence and genital numbness in cyclists.

Cyclists often complain of genital numbness and even of impotence. The purpose of this study was to determine if perineal compression during cycling causes changes in the penile blood supply, impotence and penile numbness. Forty healthy athletic men with a mean age of 30 +/- 5.3 years took part in the study. Transcutaneous penile oxygen pressure was obtained using a device consisting of a modified Clark pO2 electrode, attached to the glans of the penis. All men were measured in a standing position before, in a seated and standing position during and in a standing position after cycling. Additionally, a detailed interview was carried out with each man. The penile blood supply--which correlates with the transcutaneous PO2 at the glans-- decreased significantly in over 70% of the test subjects during cycling in a seated position. Cycling in a standing position did not show any alteration in the penile blood supply as compared to the values measured before exercising. Numbness of the genital region was reported by 61% of the cyclists. 19% of cyclists who had a weekly training distance of more than 400 km complained of erectile dysfunction. The results of the present study showed that there is a deficiency in penile perfusion due to perineal arterial compression. This could be a reason for penile numbness and impotence in long-distance cyclists. Therefore, we suggest restricting the training distance, and taking sufficient pauses during the course of prolonged and vigorous bicycle riding, in order to avoid penile numbness and impotence.

Adult↗
PubMed2001

Significance of fluorescence cystoscopy for diagnosis of superficial bladder cancer after intravesical instillation of delta aminolevulinic acid.

OBJECTIVES: Most lesions of superficial bladder cancer may be easily missed during conventional white light cystoscopy. The aim of this work was to evaluate the efficiency of endoscopic fluorescence diagnosis of superficial malignant bladder tumours following intravesical instillation of delta-aminoleviulenic acid. PATIENTS AND METHODS: 30 patients of suspected or previously diagnosed bladder cancer were subject of evaluation. All patients received 50 ml of a 3% delta-ALA solution intravesically, 2-3 h prior to diagnostic cystoscopy. Fluorescence excitation intraoperatively was achieved by a violet-blue light from a xenon light source. RESULTS: A clear strong red fluorescence colour was observed emitting from all malignant vesical lesions. A diagnostic sensitivity of 98% and specificity of 65% has been determined for this novel diagnostic modality. CONCLUSION: Fluorescence cystoscopy using delta-ALA is a reliable procedure that can be offered to all patients with suspected bladder cancer lesions.

Adenocarcinoma↗
PubMed2001

Comparison of individual urologists' performance.

OBJECTIVE: In the last few years, comparative outcome quality statistics have been one of the key topics for discussion in health care. Comparative audits using overall mortality and morbidity figures can be misleading as they do not take into account variations in urological procedure and patient fitness. The purpose of our study was to compare the crude operative morbidity and mortality rates with the predicted rates using an established scoring system (POSSUM). MATERIALS AND METHODS: To examine these effects, we compared 5 urological operations (transurethral resection of the prostate, transurethral resection of the bladder, radical nephrectomy, suprapubic enucleation of the prostate and radical prostatovesiculectomy) performed by 2 urologists in a prospective study during a 12-month period. POSSUM consists of a simple preoperative physiological score, a postoperative score and defined kinds of complications. RESULTS: One urologist operated on 160 patients, with an operative mortality of 2.5% and morbidity of 31.3%. The other urologist operated on 144 patients, with an operative mortality of 0.7% and morbidity of 9%. At first sight, there appear to be significant differences in operative outcome between the 2 urologists. However, analysis using the POSSUM system predicts a mortality rate of 3.1% for the first urologist and 0.7% for the second urologist (morbidity rates of 35% for the first urologist and 10.4% for the second urologist). Receiver operating curve analysis demonstrated no significant difference between the 2 urologists. CONCLUSION: The present study demonstrates how misleading crude mortality and morbidity figures can be when comparing different urologists. By producing a single assessment of physiological status at the time of operation and of operative severity, POSSUM analysis allows a more realistic comparison between different urologists.

Medical Audit↗
PubMed2001

Erectile dysfunction in cyclists. Is there any difference in penile blood flow during cycling in an upright versus a reclining position?

OBJECTIVE: Perineal compression during bicycling appears to be responsible for some cases of erectile dysfunction. MATERIAL AND METHODS: In 46 healthy athletic men transcutaneous penile oxygen pressure (tpO(2)) at the glands of the penis was measured, using a transcutaneous measurement device. It has been shown that the tpO(2) levels measured at the glans correlate with the penile blood flow. Our measurements were performed before, during and after cycling in an upright and a reclining position in a crossover study. RESULTS: The mean transcutaneous pO(2) at the glans in a standing position before biking was 60.5+/-8.1 mm Hg. It decreased after sitting on the saddle in an upright position to 17.9+/-3.9 mm Hg. Continued cycling in a seated upright position showed pO(2) levels of 18.3+/-5.2 mm Hg, with a full return to normal pO(2) values after a 10-min recovery period in a standing position. Cycling in a reclining position resulted in pO(2) levels of 59.4+/-4.2 mm Hg, a similar level to that obtained before exercising. CONCLUSIONS: The results of the present study demonstrated that there is a deficiency in penile perfusion caused by perineal arterial compression. Cycling in a reclining position - in which no perineal compression was seen - caused no alteration in penile blood flow during exercising. Therefore, we suggest cycling in a reclining position to avoid health hazards - such as penile numbness and hypoxygenation of the corpora cavernosa, which can result in impotency.

Adult↗
PubMed2001

Measurement of vaginal and minor labial oxygen tension for the evaluation of female sexual function.

PURPOSE: Female sexual dysfunction is a new, rapidly expanding area of sexual medicine. Female sexual arousal disorder may, in part, be due to decreased pelvic blood flow. Therefore, we developed a simple noninvasive reproducible technique to measure vaginal and minor labial blood flow. MATERIALS AND METHODS: The study included 12 healthy young women able to have orgasm through self-stimulation. Observations at orgasm were recorded in the 12 subjects after self-stimulation. Measurements were obtained intravaginally and on the minor labia using a modified Clark oxygen electrode to obtain partial oxygen pressure (pO(2)). RESULTS: Mean basal vaginal value was 3.8 +/- 0.9 mm Hg and mean basal pO(2) on the minor labia was 18.3 +/- 3.7 mm. Hg. As soon as self-stimulation was initiated an increase in oxygen tension occurred and continued during sexual stimulation. Just before orgasm a further increase was noted with peak values measured immediately after the orgasm began (pO(2) 28.6 +/- 3.1 mm Hg intravaginally and 47.3 +/- 4.1 labial). Labial pO(2) measurement decreased relatively rapidly soon after orgasm. The time to return to basal vaginal values after orgasm varied from 20 to 30 minutes. CONCLUSIONS: Previously, changes in female sexual arousal responses have been difficult to evaluate and quantify clinically. We developed a simple noninvasive reproducible technique to measure vaginal and minor labial blood flow. Age based and cycle dependent normograms now can be produced for vaginal and labial blood flow using this method.

Adult↗
PubMed2001

Risk adjustment for evaluating the outcome of urological operative procedures.

PURPOSE: Considerable public and media attention has been directed in recent years toward comparing performance at individual hospitals. So-called death league tables have been published in the media, ranking hospitals according to crude mortality rates. Crude rates of mortality and morbidity are clearly misleading. Therefore, scoring systems comparing treatment outcomes among physicians or hospitals on an objective basis are urgently required. MATERIALS AND METHODS: During a 12-month period we prospectively evaluated 651 patients at 2 urological units using a simple and well validated surgical scoring system. Patients had been admitted to the units for routine urological operations. The scoring system consists of a simple preoperative physiological score, a postoperative severity score and defined types of complications. RESULTS: The morbidity and mortality rates for unit 1 were 7.4% and 1.3%, respectively. For unit 2 the morbidity and mortality rates were 14% and 8.8%, respectively. Despite the marked differences in these crude rates risk adjusted analysis revealed no significant difference (p <0.05). Receiver operating characteristics curve analysis likewise demonstrated no significant difference in mortality and morbidity for the 2 units. CONCLUSIONS: Raw rates of mortality and morbidity are often inappropriately used to compare the performance of various surgical procedures, especially vascular and cardiothoracic surgery. In Great Britain at some institutions urological units are ranked according to mortality and morbidity outcome. As a consequence, important variables, such as patient physiological state at surgery and the type of procedure, are not considered. Our study shows that the scoring system applied is suitable for urological audit and may be a valuable tool for comparing performance at various units.

Female↗
PubMed2000

Helicobacter pylori gastritis: a Th1 mediated disease?

Helicobacter pylori is now considered to be the main cause for most stomach diseases including ulcer, MALT lymphoma, adenocarcinoma and gastritis. The infection with this bacterium is chronic despite a local and systemic immune response towards it. Among the cellular infiltrate that arises during H. pylori-mediated gastritis, there is a considerable frequency of CD4+ Th1 cells producing IFNgamma, but not of Th2 cells producing IL-4. Since IFNgamma may induce binding of H. pylori to gastric epithelial cells followed by apoptosis of these cells, one may speculate that H. pylori-mediated diseases are in part autoimmune diseases initiated by H. pylori-specific Th1 cells infiltrating the gastric mucosa. Recent support for this hypothesis comes from an animal model in which mice are infected with H. pylori and display strongly reduced gastritis in the absence of IFNgamma.

Animals↗
PubMed2000

Artificial tear adsorption on soft contact lenses: methods to test surfactant efficacy.

Spoilage is a primary factor in the biocompatibility of soft contact lenses (SCL) within the lacrimal fluid. Tears are a complex mixture of proteins, lipids, natural surfactants and salts. The spoilation process is due to a contribution of all these components and of the nature of SCL materials themselves. The aim of this study was to set up methods to observe and quantify lacrimal deposits and to select efficient surfactants for preventing protein deposits. The present study was performed on PMMA-NVP SCL. The behaviour of SCL in presence of tears was studied by means of an in vitro artificial tear model consisting of the main tears components and quantified by a colorimetric technique (BCA) performed directly on the lenses. The nature of the deposit was observed directly by atomic force microscopy (AFM) in a liquid medium showing the same adsorption trend noticed in the quantitative results and identifying specific adsorption sites. The assessment of surfactant adsorption was performed using Maron's method, as a mean to evaluate the affinity of surfactant to the surface, while the action of selected surfactants on pre-treated SCL was assessed using the BCA method. Promising results were obtained with these two different methods which can be used easily for the pre-selection of surfactants for further cleaning solution formulation studies.

Adsorption↗
PubMed1999

Protein encapsulation within poly(ethylene glycol)-coated nanospheres. II. Controlled release properties.

The development of injectable nanoparticulate "stealth" carriers for protein delivery is a major challenge. The aim of this work was to investigate the possibility of achieving the controlled release of a model protein, human serum albumin (HSA), from poly(ethylene glycol) (PEG)-coated biodegradable nanospheres (mean diameter of about 200 nm) prepared from amphiphilic diblock PEG-poly(lactic acid) (PLA) copolymers. HSA was efficiently incorporated into the nanospheres, reaching loadings as high as 9% (w/w). Results of the in vitro release studies showed that it is possible to control the HSA release by choosing the appropriate nanosphere size, loading, and composition. These results also revealed that, following their release, HSA molecules readsorbed onto the nanospheres surfaces when they were not protected by a PEG coating. We were surprised to observe that in spite of the water uptake of the PLA-PEG nanospheres [11-29% (w/w)], the copolymer did not significantly degrade after a 15-day incubation period. Therefore, we concluded that during this time HSA release from PLA-PEG nanospheres followed a diffusion mechanism where bulk erosion and surface desorption were negligible.

Biodegradation, Environmental↗
PubMed1999

Protein encapsulation in biodegradable amphiphilic microspheres.

MPOE-PLA microspheres containing bovine serum albumin (BSA) were prepared by the double emulsion method with high encapsulation efficiency ( approximately 93%). Confocal scanning microscopic analysis using MPOE-PLA labelled with 1-pyrenemethanol showed the MPOE coating of the microsphere surface. This coating improves the performance of the release system compared with PLA microspheres; the hydrophilic chains reduce the BSA adsorption onto the microspheres and increase the amount of BSA released in the supernatant. Microsphere analysis using atomic force microscopy showed that the presence of the MPOE chains also leads to surface roughness. Studies of the diffusion of 1% rhodamine aqueous solution into the microspheres by means of confocal microscopy showed a fast diffusion of water through the matrices containing high molecular weight MPOE chains (?10 000 g mol-1) and could explain the fast release of BSA from these microspheres.

Adsorption↗