Search PubMed⌕ Search

Biomedical subjects

U Jonas

Publications and source records attributed to U Jonas.

At least 73 records · Page 4Linked to original sources
PubMed2000

Long-term results of a multicenter study on sacral nerve stimulation for treatment of urinary urge incontinence, urgency-frequency, and retention.

Many patients have chronic, debilitating symptoms of voiding dysfunction that are refractory to conventional medical or surgical therapies. This multicenter, prospective study evaluated the long-term effectiveness of sacral nerve stimulation using the implantable Medtronic InterStim therapy for urinary control in patients with otherwise intractable complaints of urinary urge incontinence, urgency-frequency, or retention. Each patient first underwent temporary, percutaneous sacral nerve test stimulation. If at least a 50% reduction in target symptoms was documented for at least 3 days, patients received a permanent Medtronic InterStim sacral nerve stimulation system that includes a surgically implanted lead and neurostimulator. Regular follow-up was conducted with outcome data. We report here on patients who have been observed from 1.5 to 3 years postimplantation. The results demonstrate that after 3 years, 59% of 41 urinary urge incontinent patients showed greater than 50% reduction in leaking episodes per day with 46% of patients being completely dry. After 2 years, 56% of the urgency-frequency patients showed greater than 50% reduction in voids per day. After 1. 5 years, 70% of 42 retention patients showed greater than 50% reduction in catheter volume per catheterization. We conclude that the Medtronic InterStim therapy for urinary control system is an effective therapy with sustained clinical benefit for patients with intractable symptoms of urinary urge incontinence, urgency-frequency, or retention.

Adolescent↗
PubMed2000

Pilot study of the transdermal application of testosterone gel to the penile skin for the treatment of hypogonadotropic men with erectile dysfunction.

Androgens influence important central and peripheral mechanisms of the erectile system. The relevance of a moderate decrease of serum testosterone level for erectile dysfunction (ED) has not been clarified so far. The aim of our study was to offer an easy transcutaneous method of androgen application. A previous study on the pharmacokinetic profile of the testosterone gel applied, showed marked elevation of the serum levels of testosterone. In our study, 46 hypogonadal patients with ED and total lack of vaginal penetration applied testosterone gel (4 mg/day; supplied by Azupharma, Germany) to the penile skin twice a day over 6-8 weeks, after a run-in period with placebo gel of 2 weeks. All patients showed decreased testosterone serum levels (<3 ng/ml) in at least two morning samples over a period of 3 weeks before treatment. Psychogenic etiology was excluded by a sexual psychologist. Patient age was 37-69 years (mean 53.5). Three patients (6.5%) responded to placebo in the run-in phase and were withdrawn from further treatment. Fifteen patients (32.6%) showed improved erection, allowing penetration and sexual intercourse. Twenty-eight patients (60.9%) did not respond to therapy. Local genital skin irritation was not observed. Elevation of peripheral testosterone was not correlated to a positive therapy response. A success-rate of 32.6% in this group of patients after exclusion of psychogenic patients and placebo-responders seems to justify further investigations. A medication period of 6-8 weeks is most probably too short to induce imaginable regenerative effects of testosterone on the erectile system. We therefore suggest that future double-blind and placebo-controlled studies should be designed for a minimum of 3 months. Testosterone gel may be a cost effective form of androgen administration.

Administration, Cutaneous↗
PubMed2000

Initial clinical experience with the selective phosphodiesterase-I isoenzyme inhibitor vinpocetine in the treatment of urge incontinence and low compliance bladder.

Current pharmacological treatment modalities for urge incontinence and low compliance bladder are limited by a low clinical efficacy and the significant side effects of the standard drugs available. Previous in vitro studies indicated a possible functional relevance of the intracellular phosphodiesterase (PDE)-1 isoenzyme in the regulation of human detrusor smooth muscle contractility. We therefore investigated the effect of the PDE-1 inhibitor vinpocetine in nonresponders to standard pharmacological therapy. In 11/19 patients (57.9%) clinical symptoms and/or urodynamic parameters were improved. Although these initial data are preliminary, they represent the first evidence that isoenzyme-selective PDE inhibition may be a novel approach to the treatment of lower urinary tract disorders.

Compliance↗
PubMed2000

Characterisation of coupling products formed by biotransformation of biphenyl and diphenyl ether by the white rot fungus Pycnoporus cinnabarinus.

Cells of the white rot fungus Pycnoporus cinnabarinus grown in glucose were able to hydroxylate biphenyl and diphenyl ether, although growth was inhibited by these substrates at concentrations above 250 microM. 2- and 4-Hydroxybiphenyl were detected as products of biphenyl metabolism and 2- and 4-hydroxydiphenyl ether as products of diphenyl ether metabolism in the culture media. After addition of 2-hydroxydiphenyl ether and 2-hydroxybiphenyl to cell-free supernatants containing laccase as the only ligninolytic enzyme, different coloured precipitates were formed. HPLC analysis revealed the formation of additional hydrophobic metabolites with one major product per transformation. Mass spectrometric analysis of the methyl derivatives of the polymer mixture indicated dimers and trimers with different binding types. The main products were identified as dimers with carbon-carbon bonds in para-position to the hydroxyl group of the monomers by mass spectroscopy and nuclear magnetic resonance spectroscopy.

Basidiomycota↗
PubMed2000

Determination of nitric oxide metabolites by means of the Griess assay and gas chromatography-mass spectrometry in the cavernous and systemic blood of healthy males and patients with erectile dysfunction during different functional conditions of the penis.

Recent research implicated that the relaxation of cavernous arterial and trabecular smooth muscle-- the crucial event in penile erection--is initiated by the release of nitric oxide (NO) from nerve terminals within the cavernous tissue as well as from the endothelia that line the lacunar spaces and the intima of penile arteries. The present study was undertaken to determine whether plasma levels of the NO metabolites nitrate (NO3-) and nitrite (NO2-) in the systemic and cavernous blood of male subjects change during different penile conditions, and whether there is a difference in the NO3- and NO2- levels of normal males and patients with erectile dysfunction (ED). Twenty-four potent adult male volunteers and 15 patients with ED were exposed to visual and tactile erotic stimuli in order to elicit penile tumescence and, in the group of healthy volunteers, rigidity. Whole blood was aspirated from the corpus cavernosum and the cubital vein, and NO3- and NO2- levels were determined in plasma aliquots by means of the Griess reaction and a method combining gas chromatography and mass spectrometry (GC-MS). The mean systemic and cavernous plasma NO3-/NO2- level in blood samples obtained from the healthy volunteers was 25-31 microM when determined by means of the Griess reaction and 37-41 microM when measured by GC-MS. Both approaches revealed that NO3-/NO2- levels in the peripheral and cavernous blood do not change appreciably during developing erection, rigidity and detumescence. Moreover, no significant differences were found between NO3-/ NO2- plasma levels in the systemic and cavernous blood samples taken from the normal subjects and patients during penile flaccidity, tumescence and detumescence. Our results may reflect the fact that NO metabolism in the corpora cavernosa in the phases of penile tumescence and rigidity may account for only a minor fraction of local levels of NO3- and NO2-, which may also derive from exogenous sources. Moreover, the basal levels of NO metabolites in the blood flushing the lacunar spaces of the cavernous body in the state of developing erection could conceal any release of NO that may occur within the penile tissue. Thus, we conclude that the quantification of NO metabolites by means of advanced detection methods, such as GC-MS, is of no use in the workup of ED.

Adult↗
PubMed2000

Relaxation of human ureteral smooth muscle in vitro by modulation of cyclic nucleotide-dependent pathways.

Phosphodiesterases (PDE) are key enzymes regulating intracellular cyclic nucleotide turnover and, thus, smooth muscle tension. Recent reports have indicated the presence of PDE isoenzymes 1, 2, 4, and 5 in cytosolic supernatants prepared from human ureteral smooth muscle homogenates and the ability of second-generation inhibitors of PDE 3, 4, and 5 to relax KCl-induced tension of human ureteral muscle in vitro. The aim of the present study was to evaluate the functional effects of recently developed, third-generation isoenzyme-selective PDE inhibitors, the nitric oxide (NO)-donating agents sodium nitroprusside (SNP) and dihydropyridine (DHP), which is also described as an antagonist of L-type calcium channels, and the adenylyl cyclase-stimulating drug forskolin on tissue tension and cyclic nucleotide levels of human ureteral smooth muscle segments in vitro. Relaxant responses of human ureteral smooth muscle were investigated in vitro using the organ bath technique. Cyclic nucleotides cAMP and cGMP were determined by specific radioimmunoassay following time and dose-dependent incubation of the ureteral tissue with the drugs. The most pronounced relaxing effects on KCl-induced tension of ureteral smooth muscle were exerted by nitrovasodilator SNP, PDE4 inhibitor rolipram, and PDE5 inhibitors E 4021 and morpholinosulfonyl-pyrazolopyrimidine (MSPP). Relaxing potency of the drugs was paralleled by their ability to elevate intracellular levels of cGMP and cAMP, respectively. Our data suggest the possibility of using selective inhibitors of PDE isoenzymes 4 and 5 in the treatment of ureteral stones and ureteral colic.

Colforsin↗
PubMed2000

The history of endocrine therapy of benign and malignant diseases of the prostate.

The discovery of endocrine therapy of diseases of the prostate can be regarded as one of the most important events in the history of medicine and in urology in particular. This article delivers an overview about scientists and clinicians involved in this work during the last 200 years. A close historical relation between the endocrine therapy of benign prostatic hyperplasia and prostate cancer can be recognized. The historical framework between the work of John Hunter in the late eighteenth century, that of Charles Brenton Huggins in the late 1930s, and that of Andrew Schally in the 1970s has been assembled herein. With respect to all the other men who contributed greatly to this medical achievement, e.g., Edward L. Keyes and Russell S. Ferguson, with their first report on radioorchiectomy for the treatment of metastatic prostate cancer in 1936, this historical vignette is intended to make them part of the historical record.

Antineoplastic Agents, Hormonal↗
PubMed2000

Systemic and cavernous plasma levels of endothelin 1 in healthy males during different functional conditions of the penis.

The role of the sympathetic adrenergic nerves in mediating the constant tone of penile flaccidity and returning the erect penis to its flaccid state is fairly well established. However, it is not yet known whether additional nonadrenergic transmitters might be involved in this process. Endothelin 1 (ET-1), a 21-amino-acid peptide with potent and long-lasting vasoconstrictor activity, may be one of the factors contributing to such control. The present study was undertaken to determine whether plasma levels of ET-1 changed during flaccidity, tumescence, rigidity, and detumescence. We determined plasma levels of ET-1 in the peripheral and cavernosal blood of 32 potent adult male volunteers, in whom penile tumescence and erection were elicited by exposure to visual and tactile erotic stimuli. Whole blood was aspirated from the corpus cavernosum and the cubital vein, and ET-1 was quantified in plasma aliquots obtained from the blood samples. Using the organ bath technique, we evaluated the contractile effects of ET-1 and norepinephrine (NE) on isolated human corpus cavernosum musculature. No significant change in ET-1 levels was observed in the peripheral or cavernosal blood in the process of developing erection, rigidity, or detumescence. The mean plasma level of ET-1 was 0.2-0.7 fmol/ml. In the organ bath, ET-1 elicited concentration-dependent contractions of isolated human corpus cavernosum, which were much more pronounced than those evoked by the adrenergic agonist NE. Our data indicate that despite the in vitro efficacy of ET-1 in stimulating contractile activity in isolated human cavernous smooth muscle, the peptide may not be of ultimate importance for the mechanism of flaccidity and detumescence in healthy males. Nevertheless, the exact role of ETs in the control of penile smooth muscle tone remains to be established.

Adult↗
PubMed2000

Tissue engineering from Adam to the zygote: historical reflections.

Tissue engineering, long a matter of myth and dream throughout the history of medicine, is now a practical reality. A wide spectrum of biological materials are used in the field of urology to treat disease and to overcome human disabilities, including tissue grafts and organ transplantation. Laboratory-engineered bioproducts for the off-the-shelf replacement and reconstruction of tissue is now almost at hand. This article presents a glimpse into the past by highlighting a number of early pioneering works in the field of tissue transplantation and cell culture technologies.

Biocompatible Materials↗
PubMed2000

Neurostimulation for lower urinary tract voiding problems.

In 1981, Tanagho and Schmidt introduced chronic electrical stimulation of the sacral spinal nerves using a permanently implanted sacral foramen electrode and a battery-powered pulse generator for treatment of different kinds of lower urinary tract dysfunction, refractory to conservative treatment. At our department, chronic unilateral electrical stimulation of the S3 sacral spinal nerve has been used for treatment of vesicourethral dysfunction in 55 patients with a mean postoperative follow-up of 44.3 months. Lasting symptomatic improvement of more than 50% was achieved in 16 of 21 patients with motor urge incontinence (76.2%) and in 22 of the 28 patients with urinary retention (78.6%). In our opinion, chronic sacral neuromodulation offers a sustained therapeutic effect to treatment responders that is not achieved by temporary neuromodulation techniques. Chronic neuromodulation should be considered predominantly in patients with urinary retention and in patients with motor urge incontinence who refuse temporary techniques or who require too much effort to achieve a sustained clinical effect.

Electric Stimulation Therapy↗
PubMed2000

Quantitation of DNA extracted after micropreparation of cells from frozen and formalin-fixed tissue sections.

Quantitation of DNA from microdissected fresh-frozen or paraffin-embedded tissue sections would be not only a valuable tool for ensuring optimum reaction conditions for many types of qualitative polymerase chain reaction (PCR) analyses, but also a prerequisite for any kind of subsequently performed genetic analyses aimed at the absolute quantitation of target sequences. The present study describes the quantitation of DNA after microdissection and extraction of cells with the PicoGreen fluorescence method. The limits of detection and of quantitative determination, respectively, have been determined by measuring dilutional series of three different DNA extractions, using either a medium-scale preparation from a solid tissue specimen or a known number of leukocytes or microdissected cells from frozen tumor sections. As corresponding limits of detection, 26, 24, and about 40 diploid genomes, and as limits of quantitative determination, 80, 73, and about 120 diploid genomes were obtained. Furthermore, it was shown that formalin fixation as well as hematoxylin staining of frozen sections with Delafield's and Mayer's alum or Weigert's iron hematoxylin before microdissection significantly diminishes the amount of extractable DNA and may lead to less reliable results, even of qualitative PCR analysis. In conclusion, the PicoGreen method allows precise quantitation of DNA corresponding to a minimum of about 120 diploid cells. It provides the basis for reliable qualitative analyses as well as the precondition for further quantitative genetic measurements from microdissected frozen or formalin-fixed and paraffin-embedded tissue sections.

DNA, Neoplasm↗
PubMed2000

Cavernous and systemic testosterone levels in different phases of human penile erection.

OBJECTIVES: To examine changes in testosterone levels in the cavernous and peripheral blood during different phases of erection because, although the determination of systemic testosterone levels has been well established in the diagnostic workup of erectile dysfunction, the exact role of testosterone in adult male sexual function remains unclear. METHODS: Blood samples were drawn simultaneously from the corpus cavernosum and the cubital vein of 54 healthy and normally potent volunteers during four different stages of the cavernous erectile tissue (flaccidity, tumescence, rigidity, and detumescence). Penile erections were induced by audiovisual and tactile stimulation, and testosterone levels were determined by radioimmunoassay. RESULTS: The mean testosterone level in the corpus cavernosum plasma during the flaccid state was 2.9 +/- 1.2 ng/mL. During tumescence and rigidity, the testosterone levels in the cavernous blood significantly increased, to 4.3 +/- 1.3 ng/mL and 4. 4 +/- 1.4 ng/mL, respectively. During detumescence, the cavernous testosterone levels dropped to 3.5 +/- 1.4 ng/mL. The changes in the testosterone levels in the peripheral plasma were less pronounced. A significant increase was also found in the peripheral testosterone levels from flaccidity (4.1 +/- 1.1 ng/mL) to tumescence (4.4 +/- 1. 4 ng/mL). No further increase in testosterone occurred during the phase of rigidity. From rigidity to detumescence, the peripheral testosterone levels dropped to 4.1 +/- 1.2 ng/mL. CONCLUSIONS: Penile erection was found to be accompanied by a significant increase in cavernous and systemic testosterone plasma levels. The estimated difference between the systemic and cavernous testosterone levels during penile flaccidity, when blood flow through the cavernous body is minimized, might be a diagnostic tool to evaluate the amount of bioavailable testosterone and the activity of testosterone receptors in the corpus cavernosum smooth musculature.

Adult↗
PubMed2000

Effects of sildenafil on cAMP and cGMP levels in isolated human cavernous and cardiac tissue.

OBJECTIVES: To further investigate the mechanism of action of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase 5 (PDE5), that has been proved to be effective in the treatment of male erectile dysfunction. We assessed the effects of sildenafil on the in vitro formation of cGMP and cyclic adenosine monophosphate (cAMP) in isolated human corpus cavernosum and cardiac muscle. METHODS: Isolated segments of human corpus cavernosum and cardiac muscle were exposed to increasing concentrations of sildenafil. The dose-dependent accumulation of cGMP and cAMP was determined in the tissue samples by means of radioimmunoassays. Responses of the isolated tissue preparations to sildenafil were compared with those obtained with the reference compounds sodium nitroprusside, forskolin, and milrinone. RESULTS: In the concentration range 0.01 to 1 microM, there was only a minor effect of sildenafil on cGMP levels in isolated human cavernous and cardiac tissues. In contrast, sildenafil was found to increase cAMP significantly in both cavernous and cardiac tissue in physiologic and supraphysiologic concentrations. The stimulation of cAMP by sildenafil was more pronounced in cavernous than in cardiac tissue. Concentrations of cGMP in the cardiac strips were unaltered by milrinone; cAMP was stimulated starting at a concentration of 0.05 microM. In the range of 0.1 to 1.0 microM, the in vitro effect of sildenafil on cAMP levels in the cardiac samples was almost equivalent to that of milrinone. CONCLUSIONS: Our findings provide a potential mechanism for the cardiovascular side effects that have been reported with sildenafil use, highlighting the fact that a "cross-talk" between cGMP and cAMP-dependent signal transduction pathways might exist in human cavernous and cardiac muscle that may be of pharmacologic significance.

Colforsin↗
PubMed2000

Responses of isolated normal human detrusor muscle to various spasmolytic drugs commonly used in the treatment of the overactive bladder.

The spasmolytic activity of flavoxate (CAS 15301-69-6) and the anticholinergic agents oxybutynin (CAS 5633-20-5), tolterodine (CAS 124937-51-5) and trospium chloride (CAS 10405-02-4), all of which are commonly utilized in the treatment of urinary incontinence, on muscarinic tension and electrically evoked contractions of isolated human detrusor smooth muscle strips was studied using the organ bath technique. Within the concentration ranges tested (trospium chloride 10(-11)-10(-6) mol/l, flavoxate and oxybutynin 10(-9)-10(-5) mol/l, tolterodine 10(-10)-10(-5) mol/l), each drug caused a concentration-dependent relaxation of the tension elicited by muscarinic stimulation and dose-dependently attenuated the contractions induced by electrical field stimulation (EFS). The effects of trospium chloride and tolterodine on carbachol-induced muscarinic tension were more pronounced than those of oxybutynin, while trospium chloride and oxybutynin were most effective in inhibiting the contractions induced by EFS. Flavoxate was significantly less effective than all other drugs tested. Regardless the individual drug concentrations needed for maximal efficacy, the potency of oxybutynin and flavoxate to reverse muscarinic tension and attenuate EFS-evoked contractions was almost comparable while tolterodine and trospium chloride were more effective in relaxing the muscarinic tension of the detrusor strip preparations than causing inhibition of EFS-induced contractions. Our results again underline the ratio for the use of nortropane analogues (trospium chloride) and phenylpropylamine cresols (tolterodine) in the treatment of frequency, urgency and urge incontinence secondary to an overactive bladder.

Carbachol↗
PubMed2000

Sexual function and fertility after treatment of testicular cancer.

As a result of the introduction of effective cisplatin-based chemotherapeutic regimens into the clinical routine, even patients with metastatic testicular cancer at initial diagnosis can be cured of their disease. Sexual dysfunction and infertility are common long-lasting sequelae in testicular cancer survivors, affecting approximately 20% of patients after the application of the different treatment modalities currently available for the treatment of early and advanced clinical stages, including retroperitoneal surgery and systemic chemotherapy. Accordingly, it has been demonstrated that fertility distress and sexual disturbances, the latter occurring in only a minority of patients after surgical or chemotherapeutic treatment of testicular germ cell tumours, substantially alter the patients' quality of life. It is even worse because testicular cancer mostly affects men in the prime of their physical, sexual and reproductive function. Although semen quality is frequently poor at initial diagnosis and further deteriorates after orchiectomy, probably because of structural abnormalities in the remaining contralateral testicle, the advent of intracytoplasmatic sperm injection promises a fertile future to most patients, even if only a few sperms are present in the ejaculate. Further long-term investigations should be initiated to clarify the impact of the different treatment modalities on fertility and sexual life. The main objective should be the identification of patients who are at increased risk of developing therapy-related physical and psychological problems.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Transformation of triclosan by Trametes versicolor and Pycnoporus cinnabarinus.

We investigated the ability of Trametes versicolor and Pycnoporous cinnabarinus to metabolize triclosan. T. versicolor produced three metabolites, 2-O-(2,4,4'-trichlorodiphenyl ether)-beta-D-xylopyranoside, 2-O-(2,4,4'-trichlorodiphenyl ether)-beta-D-glucopyranoside, and 2,4-dichlorophenol. P. cinnabarinus converted triclosan to 2,4, 4'-trichloro-2'-methoxydiphenyl ether and the glucoside conjugate known from T. versicolor. The conjugates showed a distinctly lower cytotoxic and microbicidal activity than triclosan did.

Anti-Infective Agents, Local↗