Re: Ethanol injection therapy of the prostate for benign prostatic hyperplasia: preliminary report on application of a new technique.
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Ethanol↗
Biomedical subjects
P Zvara
Publications and source records attributed to P Zvara.
Pheochromocytoma of the urinary bladder: update on new diagnostic modalities plus case report.
Extra-adrenal pheochromocytoma (PCC) is a rare entity. Its occurrence in the urinary bladder has only been reported less than 200 times. Here we present two case reports of a bladder PCC with an update on the diagnostic techniques, treatment modalities and follow-up of patients with this disease.
Female↗
The Internet and patient education--resources and their reliability: focus on a select urologic topic.
OBJECTIVES: The information revolution triggered by the rapid growth of the Internet has allowed healthcare providers and patients to access a rapidly expanding volume of information. To address the quality of this information, a survey of the data on a single urology-related topic available on the Internet was performed. METHODS: The search on the World Wide Web (Web) was performed using the search engine HotBot and search directory Yahoo. The Web pages were assessed according to their relevancy to the topic chosen. Relevance rates were derived from the number of relevant sites divided by the total number of sites found. Relevant sites were subsequently ranked for quality on the basis of their accuracy, comprehensiveness, and objectivity. HotBot was then subsequently divided by domain, with each assessed separately. Yahoo was analyzed in its entirety. The resources were then compared for relevance and quality of information. RESULTS: When using the keyword "Viagra," HotBot responded with 15,109 hits. Yahoo presented 51 hits under the category, "Health: Pharmacy: Drugs and Medications: Specific Drugs and Medications: Viagra (Sildenafil)." The relevance rate for the first 50 hits in the search engine HotBot was 0.08. The relevance rates for the edu and org domains found by HotBot were 0.22 and 0.24, respectively; those for com and net were both 0.10. The relevance rate for the search directory Yahoo was 0.20. For relevant sites, the quality of the information presented was significantly higher in the Yahoo and in the HotBot domains hosted by nonprofit organizations when compared with HotBot in general and with its commercially oriented domains. HotBot overall was found to contain seven excellent sites, of which only three were found within Yahoo. CONCLUSIONS: Although the medical information available on the Web has proliferated at a remarkable rate, the number of Web sites providing complete, nonbiased information continues to represent only a small portion of the total. We have shown that the search directory Yahoo reduced the number of irrelevant sites significantly, but at the same time, some very valuable information available in HotBot was missing. At present, it may be useful to conduct searches within Yahoo followed by a review of both the edu and org HotBot domains.
Erectile Dysfunction↗
Ablation of canine prostate using transurethral intraprostatic absolute ethanol injection.
OBJECTIVES: Despite extensive research involving numerous treatments for benign prostatic hyperplasia (BPH), the ideal modality has yet to be discovered. This study evaluated chemoablation of the prostate using transurethral intraprostatic absolute ethanol injection (AEI) in an in vivo canine model. METHODS: Eight mongrel dogs, 7 to 10 years old, underwent transurethral intraprostatic AEI with various ethanol volumes (10 to 26 mL/animal, mean 19.9). Injection was performed using a 20-gauge, passive deflection, hollow-core needle, introduced cystoscopically by way of a perineal urethrotomy. Oral antibiotics were administered perioperatively. Blood alcohol levels were determined. The canines were kept alive for 1 hour (n = 1), 7 days (n = 2), and 21 days (n = 5) after the treatment. The dogs were observed twice daily for a minimum of 30 minutes to determine continence. At least one spontaneous voiding was recorded at each observation. Before the dogs were sacrificed, the prostate and surrounding tissues were harvested, with gross and microscopic examination performed by a single pathologist. RESULTS: Seven and 21 days after AEI, the prostates demonstrated necrosis and cavity formation. Deep injection resulted in cavity formation in a subcapsular location. Superficial injection resulted in cavity formation that was confluent with the urethra and resulted in a widened urethral lumen. No complications directly related to AEI were seen, and systemic absorption of ethanol was minimal. CONCLUSIONS: AEI can effectively ablate prostatic tissue in canines with minimal systemic absorption. No disruption of the prostatic capsule or injury to the bladder urothelium and urethral sphincter was identified. Human studies of intraprostatic AEI for BPH adenomatous tissue chemoablation are ongoing at our institution.
Animals↗
Evaluation of the role of neurolinins and urecholine hypersensitivity in an animal model of infravesical outflow obstruction.
OBJECTIVES: To determine whether detrusor muscle strips from a male rat with infravesical outflow obstruction model demonstrate supersensitivity to parasympathomimetic and neurokinin NK-1 and NK-2 selective agonists. METHODS: Bladder instability developed after 6 weeks of partial urethral obstruction. The micturition frequency and voided volume were determined in unanesthetized animals. Detrusor hypertrophy was confirmed by evaluation of bladder weight. In vitro organ bath was used to compare the affinity and maximal activity of bethanechol and neurokinin NK-1 and NK-2 selective agonists on strips from the detrusor muscle of sham and obstructed rats. Bethanechol, N-Ac[Arg6, Sar9, Met(O2)]-SP(6-11), and [beta-Ala8]-NKA(4-10) were used to characterize cholinergic muscarinic, neurokinin NK-1 and NK-2 receptors. Results. No significant differences in affinities and maximal responses were found using 10-mg detrusor muscle strips with each of the three agonists. CONCLUSIONS: Bladder instability produced by outlet obstruction does not involve changes in the affinity or maximal activity of cholinergic muscarinic, neurokinin NK-1 and NK-2 receptors. Furthermore, detrusor supersensitivity to neurokinins or bethanechol was not seen. This suggests that bladder instability is not due to an increased affinity or maximal response to neurokinins or parasympathomimetics.
Animals↗
An animal model for the neuromodulation of neurogenic bladder dysfunction.
OBJECTIVE: To develop an animal model to examine the pathophysiology by which S3 sacral root electrostimulation alters the micturition reflex in patients with bladder hyper-reflexia. MATERIALS AND METHODS: Chronic sacral nerve root electrostimulation was applied to spinally transected rats; 21 animals were divided into four groups. The spinal cord was completely transected at the T10-11 level and stainless-steel electrodes implanted into the sacral foramen in 17 animals; these animals were subsequently divided into two groups (1 and 2). Six rats in group 1 underwent sacral root elctrostimulation for 2 h/day and five in group 2 for 6 h/day, for 21 days. The sham group (group 3, six rats) received no stimulation and four rats were used as healthy controls (group 4). Voiding frequency was recorded and each animal was evaluated cystometrically at the end of the stimulation period. The results were compared with the sham and control groups. RESULTS: Spinal cord transection resulted in bladder areflexia and complete urinary retention; 7-9 days after the injury, the bladder recovered its activity. Twenty-one days after transection all animals had evidence of uninhibited bladder contractions. The mean (SD) hourly frequency of urination was 0.66 (0.18) in healthy controls, 0.83 (0.21) in group 1, 0.87 (0.34) in group 2 and 1.1 (0.31) in group 3. There was a significant decrease in eh cystometric signs of bladder hyper-reflexia in groups 1 and 2 when compared with group 3. CONCLUSIONS: This work reports and initial study showing that chronic electrostimulation of sacral nerve roots can reduce the signs of bladder hyper-reflexia in the spinally injured rat. To our knowledge, this is the first report describing the rat as an animal model to determine the effects of chronic electrostimulation on the micturition reflex.
Animals↗
7-Nitroindazole: a selective inhibitor of penile erection: an in vivo study in a rat animal model.
OBJECTIVES: The neuronal isoform of nitric oxide synthase (nNOS) has been localized in neurons innervating the penis and is believed to be an important mediator of erection. Using the selective inhibitor 7-nitroindazole (7-NI), we evaluated the possible role of nNOS in penile erection using a rat animal model. METHODS: Eighteen Sprague-Dawley rats were divided into three study groups. A sham group (n = 6) received the vehicle arachis oil, a low-dose group received 5 mg/kg (n = 6), and a high-dose group received 50 mg/kg (n = 6) of 7-NI prior to measurement of blood pressure and cavernous nerve stimulation-induced rise in intracavernous pressure. RESULTS: A dose-dependent inhibition of erection by 7-NI was seen. Control animals had an intracavernous pressure rise of 55.5 +/- 4.0 cm H2O, whereas the low-dose group had 26.5 +/- 2.8 cm H2O and the high-dose group had 6.2 +/- 2.1 cm H2O. A partial recovery of erection was seen in the low- and high-dose groups after 3 hours. Blood pressure was unaffected by 7-NI administration. CONCLUSIONS: 7-NI induced a reversible, dose-dependent inhibition of erection without affecting blood pressure. This in vivo study provides further evidence of the role played by nNOS in erection.
Analysis of Variance↗
Neurogenic erectile dysfunction: the course of nicotinamide adenine dinucleotide phosphate diaphorase-positive nerve fibers on the surface of the prostate.
OBJECTIVES: Nitric oxide (NO) plays an important role as a neurotransmitter in the peripheral neural regulation of erection. A histochemical stain able to localize fibers releasing NO in combination with an in vivo study were used to evaluate the course and physiologic significance of the nerve fibers innervating the cavernous smooth muscle. METHODS: Morphologic studies in 6 rats and 6 human cadavers were performed, tracing the course of branches of the cavernous nerve branches using a nicotinamide adenine dinucleotide phosphate diaphorase staining technique. Electrostimulations in rats were performed before and after transection of the anterolateral part of the prostate capsule. RESULTS: Multiple nerve fibers were documented running on the lateral and ventral surfaces of the prostate distinct from the classically described dorsolateral neurovascular bundle. Transection of these fibers resulted in a loss of electrically induced intracavernous pressure (59.4 +/- 5.6 cm H2O versus 27.0 +/- 4.6 cm H2O). CONCLUSIONS: These preliminary morphologic and physiologic studies support a significant role for these nerve fibers in erection.
Animals↗
Transurethral Nd:YAG laser prostatectomy with a laterally firing fiber: local effects on tissue associated with erectile dysfunction.
BACKGROUND AND OBJECTIVES: Transurethral laser prostatectomy is anticipated to become a recognized alternative to conventional transurethral resection of the prostate. However, the effects of this procedure on the nerves of the pelvic plexus and erectile dysfunction remain unaddressed. The objective of this study was to evaluate the effects of laser energy on extent of prostatic damage as well as injury to periprostatic cavernosal nerves and erectile dysfunction in a canine model. STUDY DESIGN/MATERIALS AND METHODS: Six adult male mongrel dogs underwent transurethral laser prostatectomy at 30 (n = 3) and 40 (n = 3) watt power settings. Total laser energy delivered varied between 6,000 and 13,800 joules. Erectile function was evaluated by pelvic nerve stimulation at 2, 4, and 8 weeks. Animals were then sacrificed to assess histopathology of the prostate at each time point. RESULTS: Histopathologic changes were noted in the prostate in a dose-dependent manner and did not vary with different laser power settings. In dogs that received approximately 10,000 J, substantial prostate ablation confined within the capsule was achieved in every prostate gland. Adequate erectile responses were noted in five of six animals; all received < 10,000 J. In one animal that received a total dose of 13,800 J, an erectile response was not obtained, and histology revealed both prostatic capsule perforation in close proximity to the cavernous nerves and thermal neural damage. CONCLUSIONS: We conclude that cavernous nerve damage may result from excessive doses of laser energy during transurethral laser treatment of the prostate gland. In canines, the upper limit for periprostatic injury is between 10 and 14,000 joules.
Aluminum Silicates↗
Regeneration of nitric oxide synthase-containing nerves after cavernous nerve neurotomy in the rat.
In patients who recover erectile function after radical prostatectomy (with preservation of at least 1 neurovascular bundle), a recovery time of 6 to 18 months is not uncommon. As this is also the usual time required for regeneration of spinal nerves, we believe that regeneration of cavernous nerves, partially damaged inadvertently, may be responsible. In a rat model, we examined the long-term effect of unilateral and bilateral cavernous nerve transection on the nonadrenergic/noncholinergic (NANC) nervous system and erectile function. In 31 rats, nitric oxide synthase (NOS), the enzyme that catalyzes nitric oxide production, was identified in penile nerve fibers from a mid-shaft segment with nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining and antibody to neuronal NOS. Animals were divided into three groups: 5 rats underwent pelvic exploration without transection of cavernous nerves (sham group); 13 rats underwent unilateral neurotomy of a 5-mm. segment of the cavernous nerve; and 13 rats underwent bilateral neurotomy. After bilateral ablation, the NOS-positive nerve fibers were significantly decreased at 3 weeks and remained so at 6 months; no erectile response could be elicited by pelvic nerve stimulation. After unilateral ablation, the NOS-positive nerve fibers were similarly decreased on the side of the neurotomy at 3 weeks, but by 6 months the number had increased significantly and approximated the level on the contralateral side. Furthermore, electrostimulation of the intact side induced a greater intracavernous pressure response at 6 months than at 3 weeks (N.B. the rat has an incomplete septum). Fibers positive for NOS were also identified in the dorsal nerve. The staining pattern diminished as rapidly and significantly on the side of neurotomy as in tissue from the corpus cavernosum. However, regeneration was not seen. To our knowledge, this is the first demonstration of regeneration of NOS-containing nerves after cavernous nerve neurotomy. Our findings support the reports by others that unilateral nerve-sparing is sufficient to preserve erectile function.
Amino Acid Oxidoreductases↗
Transformation of the Bricker to a continent urinary reservoir to eliminate severe complications of uretero-ileostomy performed in eight patients among 200 Bricker.
Between 1969 and 1994 urinary diversion via the ileal loop (Bricker's operation) was performed in 200 patients. After introduction of methods of continent urinary diversion into clinical practice, some of young patients operated in childhood for congenital lower urinary tract malformations demanded the conversion of the primary diversion. The decision was influenced, however, not only by subjective complaints but also by severe complications having relation to the long-lasting presence of stoma. A modified Mainz pouch I, with a catheterizable stoma was constructed in 6 patients with primary uretero-ileostomy made 7 to 22 years prior to conversion because of exstrophy of the urinary bladder or a neurogenic bladder with total urine incontinence. The ileal loop used for uretero-ileostomy was detubularized or combined with additional segments of ileum and colon. The ileal stoma was connected to the umbilicus. In other two patients suffering from a neurogenic bladder the uretero-ileostomy was converted to an orthotopic ileal pouch. The authors present long-term results (1.5 to 7 years) of follow-up with urodynamic and radiological evaluation. The results both compensate the urologist's efforts and enhance the patient's quality of life.
Adolescent↗
Nitric oxide mediated erectile activity is a testosterone dependent event: a rat erection model.
Classically, androgens were thought to be linked to sexual activity in man through their action on increased libido. Recently, the sex hormone dependent nature of nitric oxide synthase (NOS), the enzyme system producing the neurotransmitter of erection (nitric oxide) has been reported. Our study evaluated how changes in testosterone levels alter erectile function. In forty-seven rats the erectile response to cavernous nerve electrostimulation was recorded 1, 5, 10, 20 and 30 d post-bilateral orchiectomy, and compared to controls. Penile tissue was subsequently stained for the presence of NOS, using an NADPH diaphorase technique. Forty eight rats were used in part two. After orchiectomy exogenous testosterone was administered and the erectile function as well as density of NOS positive nerve fibers was assessed. All castrated animals showed a rapid decrease in serum free testosterone levels within 24 h. In contrast, a gradual decrease in intracavernous pressure was recorded with cavernous nerve stimulation, proportional to the time post orchiectomy. NADPH diaphorase staining showed a decreased density of nonadrenergic noncholinergic (NANC) nerve fibers innervating the cavernosal tissue proportional to the time post orchiectomy. With reconstitution of the androgen mileu the erectile response returned to near normal values and recovery of NADPH-positive nerve fibers was observed. Based on presented data we conclude that testosterone or a metabolite plays a direct role in erection acting through an effect on nitric oxide synthase within the corpora cavernosa.
Animals↗
Laparoscopically implantable nerve-stimulating electrode (LINSE): application to the cavernous nerve in acute and chronic canine models.
Using a new laparoscopic procedure, we investigated stimulation of the cavernous nerves to achieve erection in a canine model. The technique was developed during acute experiments in four dogs, following which, chronic studies (4- to 6-weeks survival after surgery) were undertaken in three dogs. A monopolar cuff electrode was inserted laparoscopically by a transperitoneal approach and placed around the cavernous nerve. The leads were brought out to the subcutaneous space, where they were attached to stimulation receivers that could be activated by an external radiofrequency transmitter. An intracavernous pressure elevation indicative of successful stimulation was obtained acutely in five of eight cavernous nerves in the four acute-study dogs and in four of six nerves in the three chronic-study dogs. The implanted equipment associated with four of six cavernous nerves failed mechanically in the chronic-study animals, such that only two receiver-electrode sites were intact at the time of sacrifice 4 to 6 weeks later. Transmitter-driven stimulation of one of these two sets produced an intracavernous pressure rise above 100 cm H2O. We present this technique as part of the continuing evolution of laparoscopy as both a research and a clinical tool. The present use of the laparoscopically implantable nerve-stimulating electrode is a new animal research tool and a potential first step in the human application of the technology.
Animals↗
The detailed neuroanatomy of the human striated urethral sphincter.
OBJECTIVE: To study the nerve supply of the striated urethral sphincter. MATERIALS AND METHODS: The pelvis from six formalin-fixed male cadavers was dissected. RESULTS: Cadaveric dissection revealed that both the intrinsic and extrinsic segments of the urethral rhabdosphincter receive their innervation from sacral roots S2-S4. The nerve fibres travel to their final destination via both the pudendal nerves and the nerve branches of the sacral roots. The terminal branches of the pudendal nerve enter the sphincteric area from the perineum. They separate shortly after they cross the ischial spine and run further ventromedially. Small branches approach the sphincter after their division from the dorsal nerve of the penis. The course of the pudendal nerve and its branching on the perineum are quite consistent. The pelvic branches travel inside the pelvis above the levator ani muscle. Among the cadavers the number of branches varied markedly, as did their site of termination (2.3 to 3.9 cm from the striated urethral sphincter). A substantial nerve approaching the sphincter from inside the pelvis was found. After it divided from the S2, S3 sacral roots it ran separately, initially just lateral to the fibres of the pelvic plexus and then on the dorsolateral surface of the rectum. In its terminal segment it dived into the levator ani muscle and terminated in the striated urethral sphincter. CONCLUSIONS: We believe that the nerve supply to the striated urethral sphincter consists of branches from both the pudendal nerve and the 'extrapudendal' nerves that run above the levator ani muscle inside the pelvis. The variations in the course of the latter are remarkable.
Humans↗
Erectile dysfunction.
A better understanding of penile physiology and pathophysiology has revolutionized the diagnosis and treatment of erectile dysfunction in the past decade. This article summarizes the current knowledge and presents a patient's goal-directed approach to the evaluation and treatment of erectile dysfunction.
Erectile Dysfunction↗
[Electrostimulation of the urinary bladder].
The authors present their first results with urinary bladder stimulation in dogs by using an electronic stimulator and electrodes of their own construction. Neurostimulation was carried out by means of contactless application of electrical rectangular pulses with the voltage ranging from 1 to 10 volts, frequency from 10 to 300 Hz and pulse with 1 ms. Due to the stimulation of the branches of the pelvis plexus an isolated contraction of the bladder detrussor with an increase of intravesical pressure up to 65 cm H2O was observed with subsequent spontaneous voiding. The stimulation of the intact sacral root S2 led to detrussor-sphincteric dyssynergia caused by simultaneous contraction of the detrussor and the striated urethral sphincter. The poststimulus spurt of urine was observed at the end of each S2 stimulation. The authors inform about the further plan of experimental work before introducing the method into clinical practice. (Fig. 4, Ref. 17.).
Animals↗
[Erectile dysfunctions in patients treated with hemodialysis and kidney transplantation].
The incidence of erectile dysfunction in patients suffering from severe renal diseases in the stage of renal insufficiency is significantly higher in comparison with healthy men of the same age. In the etiopathogenesis of erectile disorders, both organic and psychogenic factors participate in combination. By means of a questionnaire, the authors have collected information from 53 men treated by hemodialysis and kidney transplantation because of renal failure. Erectile disorders occurred in 41.5 per cent of men with chronic renal insufficiency. On one side hemodialysis improved the erectile dysfunction in two patients, in total, however, the incidence of impotence increased to 64.2 per cent. Erectile dysfunction was reported by 71.7 per cent of patients after kidney transplantation. The authors describe two cases of iatrogenic arterial insufficiency of the penis as the cause of impotence after secondary renal transplantation. In uremic patients as possible therapeutic methods, intracavernous application of vasoactive drugs or penile prostheses implantation should be considered. (Fig. 2, Ref. 20).
Adult↗
[A screening program for the diagnosis of early forms of prostatic carcinoma].
Carcinoma of the prostate is at present one of the most frequently occurring malignancies in the male population. The disease can be cured only at the early stage when it has not yet spread beyond the limits of the gland. Early, clinically asymptomatic forms of carcinoma of the prostate can be diagnosed only by screening examinations of men. The justification of screening has, however, not been conclusively established and the fear of damaging the patient on examination could not be dispelled. The project of an international co-operative study was accepted in Stockholm in 1990 with the aim to address this question. The Department of Urology of Derer's Hospital with Policlinic, along with several urological, oncological, and research departments, have decided to join the project in order to contribute to the improvement of diagnosis and treatment of carcinoma of the prostate. (Fig. 1, Ref. 12.).
Humans↗