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Y Vardi

Publications and source records attributed to Y Vardi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Possible role for endothelins in penile erection.

The effects of endothelins (endothelin-1 and endothelin-3) on penile erection were studied in vivo in the pithed rat. Penile erectile responses were evaluated by measurements of intracorporal pressure via a needle inserted into one corpus cavernosum. Injection of endothelins (0.1-10 micrograms/kg i.v.) was followed by a rapid rise in corporal pressure. The responses to endothelin-1 and endothelin-3 were equivalent at the lower doses, but at 10 micrograms/kg the response to endothelin-3 was greater than that to endothelin-1. NG-Nitro-L-arginine-methyl ester (20 mg/kg) but not indomethacin (10 mg/kg) antagonized the rise in corporal pressure caused by submaximal doses of endothelins. Electrical nerve stimulation-induced increase in corporal pressure was reduced after 5 micrograms/kg endothelin-1 but not after the same dose of endothelin-3. The results indicate that in corporal vasculature endothelin-3 has a predominantly vasodilator effect, while endothelin-1 has a vasodilator effect at lower doses and a vasoconstrictor effect at higher doses. The vasodilator action of endothelins is probably mediated by activation of endothelin ETB receptors and local release of nitric oxide. Thus, endothelins may participate in initiation and/or maintenance of penile erection.

Animals↗
PubMed1996

Penile thermal sensation.

PURPOSE: To our knowledge no direct measurement of autonomic failure in the penis is currently available. Indirect techniques in clinical use, such as bulbocavernosus reflex, genital somatosensory evoked potentials and biothesiometry, all rely on large nerve fiber function. Since micturition and potency depend on small fibers of the peripheral system, tests of these fibers might be more relevant in the clinical diagnostic evaluation. We provide upper normal limits and demonstrate repeatability of small fiber mediated sensations of warm and cold sensory thresholds on penile skin. MATERIALS AND METHODS: Penile warm and cold sensory thresholds were measured in 35 healthy volunteers (at 2 sessions in 27) via 2 methods. RESULTS: Upper normal values, expressed as 95% confidence limits for warm and cold thresholds, through methods of limits and levels as well as inter-session repeatability are given. CONCLUSIONS: Penile thermal thresholds are repeatable and can be used as a valid diagnostic tool to assess somatic small fiber function in patients with lower urinary tract disorders.

Adult↗
PubMed1996

Validation of the 50 ml3 drinking test for evaluation of post-stroke dysphagia.

Aspiration pneumonias are frequent complications of cerebrovascular accidents (CVA). They occur mainly in patients suffering from swallowing disorders following the CVA. These patients can be diagnosed using a bedside swallowing evaluation. This evaluation is based on observation of some components of the oral and pharyngeal stages of the swallowing process and on a drinking test of 50 ml3 of clear liquids. Changing the mode of swallowing and the consistency of the diet according to the swallowing evaluation following CVA can reduce significantly the frequency of aspiration pneumonias. In our patient cohort, consisting of 180 patients admitted for stroke rehabilitation, aspiration pneumonias occurred in 10% and swallowing disorders were found in 28%. The administration of a structured swallowing evaluation was associated with a gradual reduction of frequency of pneumonia from 16% in the first group of 60 patients to 3% in the last group of 60 patients or, if considering only patients suffering from dysphagia, from 27% in the first group of patients to none in the last group of patients.

Aged↗
PubMed1996

Polyneuropathy in impotence.

Three hundred and forty-one consecutive impotent patients were evaluated for the presence of polyneuropathy (PNP) by neurophysiological and psychophysical tools, including nerve conduction and quantitative sensory tests (thermal and vibratory). PNP was present in 38% of diabetics, and 10% of non diabetics. Overall, PNP was found in 19% of impotent patients. PNP is relatively common among impotent patients, and might play a causative role. Patients judged 'neurogenic' and those judged 'vasculogenic', based on nocturnal tumescence test (NPT) and vasoactive drug injection tests, had very similar rates of PNP (21 and 23%, respectively). Thus it is suggested that the vasoactive drug injection test does not serve in discriminating neurogenic from non-neurogenic impotence. NPT, however, faithfully discriminates psychogenic from organic impotence, as far as PNP is involved, since a very low percentage of patients with normal NPT had PNP.

Adolescent↗
PubMed1995

Papaverine-phentolamine and prostaglandin E1 versus papaverine-phentolamine alone for intracorporeal injection therapy: a clinical double-blind study.

PURPOSE: A study was designed to compare intracorporeal injections of papaverine plus phentolamine (2-drug solution) and papaverine plus phentolamine and prostaglandin E1 (3-drug solution) for the treatment for impotence. MATERIALS AND METHODS: A total of 20 impotent patients received intracorporeal injections of the 2-drug or 3-drug solution alternately during 2 sessions, and the quality and duration of erections were assessed. RESULTS: Of the patients 73% achieved a full erection with the 3-drug solution compared to 28% with the 2-drug solution. The average duration of erections was 57 minutes and 33.6 minutes, respectively. The complication rate was similar for the 2 treatments. CONCLUSIONS: Papaverine plus phentolamine and prostaglandin E1 is superior to papaverine plus phentolamine alone for the treatment of impotence.

Adult↗
PubMed1995

Corpus cavernosum electromyogram: spontaneous and evoked electrical activities.

Sympathetic skin responses recorded from the surfaces of limbs and the penis resemble the waveforms recorded by needle from the corpora cavernosa. Thus, corpus cavernosum electromyography might reflect a systemic sympathetic response rather than unique smooth muscle corporeal activity. We recorded electrical activity simultaneously from the corpora and limbs of 10 subjects. Spontaneous activity was unique to the corpora, while electrical activity in response to sympathetic activating maneuvers was found simultaneously in the corpora and limbs (Fisher's exact test, p < 0.001). It is concluded that 2 types of electrical activity can be recorded from the corpora--spontaneous activity, which might reflect specific smooth muscle activity, and response activity, which is part of the systemic response to sympathetic stimulation.

Adult↗
PubMed1993

Bladder sensory power factor (BSPF): a novel diagnostic tool.

A simple clinical test for assessment of sensory function of the urinary bladder is described. It is performed during urodynamic assessment, consisting of stepwise filling of the bladder by gas. Subjects give numerical description of the perceived magnitude of pressure at each step, using an open-ended ratio scale. Based on Stevens law of psychophysics, the bladder sensory power factor (BSPF) is extracted from these data, reflecting the sensory state of the bladder. A BSPF of 1.01 +/- 0.12 (mean +/- SD) was found for 13 normal subjects. For 20 patients with lower urinary tract complaints who had a lesion of lumbosacral nerve roots, the BSPF was 0.59 +/- 0.23 (P < 0.001, t-test). In 16 (80%) of them BSPF was lower than 0.77 (= normal mean -2 SDs), being markedly more sensitive than the punctual sensory parameters-bladder sensory threshold (25%) or capacity (35%). BSPF is presented as a sensitive and easy to perform test for assessment of the sensory function of the human urinary bladder.

Adult↗
PubMed1993

Hemodynamics of pelvic nerve induced erection in a canine model. II. Cavernosal inflow and occlusion.

Using a previously developed canine model of erection, we measured pudendal artery and venous flow as well as pressure in the corpora cavernosa, pudendal artery and vein. Penile erection was induced by pelvic nerve stimulation. Generalized arterial vasodilatation was dependent on stimulation frequency and occurred most prominently at stimulation frequencies of approximately 16 Hz. Cavernosal smooth muscle relaxation was also frequency dependent in a similar manner. In contrast, using a technique of delayed arterial inflow, we demonstrated that helicine artery relaxation was very sensitive to stimulation frequency and occurred only at a stimulation frequency of approximately 16 Hz. The mechanism of corporal occlusion is primarily dependent on nerve-induced relaxation of the cavernosal smooth muscle. The frequency-dependent nature of pelvic nerve induced erection is primarily due to the frequency dependence of the cavernosal resistance vessels that control arterial inflow to the cavernosal spaces.

Animals↗
PubMed1993

Inhibition of nerve stimulation-induced vasodilatation in corpora cavernosa of the pithed rat by blockade of nitric oxide synthase.

1. The effect of inhibition of nitric oxide synthase by NG-nitro-L-arginine methyl ester (L-NAME) on nerve stimulation-induced vasodilation in corpora cavernosa was studied in the pithed rat. Corporal vasodilation was estimated by the increase in ratio (corpora cavernosal pressure/systemic blood pressure; CP/BP) following electrical stimulation of the sacral part of the spinal cord. 2. L-NAME (2, 5, 10 and 25 mg kg-1) caused an increase in BP and a dose-dependent inhibition of the rise in the CP/BP ratio following stimulation. 3. The inhibitory effect of L-NAME (25 mg kg-1) on the corporal response to spinal cord stimulation, as well as the pressor response, was partially prevented by prior administration of L- but not D-arginine (400 mg kg-1, i.v.). 4. L-NAME (20 mg kg-1, i.v.) did not inhibit the rise in corporal pressure resulting from direct intracavernosal administration of papaverine (400 micrograms over 2 min). However, this response was inhibited by 5-hydroxytryptamine (20 micrograms kg-1, i.v.). 5. The results are indicative of a role of nitric oxide (NO) in the corporal vasodilator response to erectile stimulation.

Amino Acid Oxidoreductases↗
PubMed1993

Oxygen tension regulates the nitric oxide pathway. Physiological role in penile erection.

Relaxation of the trabecular smooth muscle of the corpus cavernosum (the erectile tissue) of the penis is mediated by nitric oxide released by the nerves and endothelium. We have investigated the physiological role of oxygen tension in the regulation of trabecular smooth muscle tone. In human subjects, measurement of intracavernosal PO2 in blood drawn from corpus cavernosum in the flaccid state was comparable to that of venous blood (25-43 mmHg). Vasodilatation of the resistance arteries and trabecular smooth muscle relaxation by intracavernosal injection of papaverine and phentolamine caused oxygen tension to rise rapidly to arterial levels (PO2 approximately 100 mmHg). Isolated human and rabbit corpus cavernosum tissue strips in organ baths, exposed to arterial-like PO2 relaxed to the endothelium-dependent dilator acetylcholine and to electrical stimulation of the autonomic dilator nerves. These nitric oxide-mediated responses were progressively inhibited as a function of decreasing PO2 to levels measured in the flaccid penis. Reverting to normoxic conditions readily restored endothelium-dependent and neurogenic relaxation. Relaxation to exogenous nitric oxide was not impaired in low PO2. In rabbit corpus cavernosum, low PO2 reduced basal levels of cGMP and prevented cGMP accumulation induced by stimulation of dilator nerves. Furthermore, low PO2 inhibited nitric oxide synthase activity in corpus cavernosum cytosol. It is concluded that physiological concentrations of oxygen modulate penile erection by regulating nitric oxide synthesis in corpus cavernosum tissue.

Amino Acid Oxidoreductases↗
PubMed1992

Abscess of corpus cavernosum.

A rare case of abscess of the corpus cavernosum is described. Culture of the abscess yielded beta-hemolytic streptococcus. Ultrasound scan and cavernosography confirmed the physical examination findings of involvement of the corpus cavernosum. The patient was treated successfully by percutaneous ultrasound-guided aspiration drainage and systemic antibiotic therapy.

Abscess↗
PubMed1992

Radionuclide assessment of penile corporal venous leak using technetium-99m-labeled red blood cells.

In an attempt to evaluate penile corporal venous outflow, a method that utilizes intracorporal injection of Tc-RBC was developed and used in 20 patients with erectile dysfunction. Seven patients showed venous leak and 13 had normal venous outflow. Technetium-labeled RBC corporal clearance in the flaccid state and after intracorporal injection of papaverine (30 mg) and regitine (1 mg) were assessed in sequence by two separate injections of 18.5 MBq of Tc-RBC each. The time for 50% corporal clearance (T50%) was determined from the time activity curves obtained in flaccid state and after intracorporal injection of the vasoactive agent. There were no statistically significant differences in T50% measured in the flaccid state between normal venous outflow (202 +/- 139 sec) and venous leak (92 +/- 35 sec, p = 0.1). However, after intracorporal injection of papaverine and regitine a significant increase in the T50% was noted in normal venous outflow (2892 +/- 1899 sec) as compared to venous leak (213 +/- 123 sec, p less than 0.001). The results suggest that measurement of corporal clearance of Tc-RBC after intracorporal injection of papaverine may be a useful method in detecting venous leak, and could be used as a screening test in patients with erectile dysfunction.

Adult↗
PubMed1991

Renal extramedullary hematopoiesis simulating hypernephroma.

We report a 63-year-old woman who presented with anemia and a left kidney mass. Guided fine-needle aspiration of the mass revealed extramedullary hematopoiesis and enabled avoiding an unnecessary operation. Subsequent bone marrow biopsy demonstrated myelofibrosis. Twenty-four months later the mass remained stable.

Carcinoma, Renal Cell↗