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Biomedical subjects

M Shalev

Publications and source records attributed to M Shalev.

At least 19 recordsLinked to original sources
PubMed1999

Stimulation of P2y purinoceptors induces, via nitric oxide production, endothelium-dependent relaxation of human isolated corpus cavernosum.

PURPOSE: Endothelial P2y purinoceptor stimulation is known to induce vasodilatation mediated by NO release from endothelial cells. We examined the effect of a potent P2y agonist, adenosine-5'-O-(2-thiodiphosphate) (ADPbetaS), on human corporal cavernosal strips and its dependence on a functional endothelial lining. MATERIALS AND METHODS: The preparations mounted in isometric conditions were precontracted by noradrenaline (NA) at a concentration of 0.1 microM. Increasing concentrations of ADPbetaS from 1 microM to 100 microM were added in the presence and absence of a functional endothelium or in the presence and absence of an NO synthase inhibitor and a selective P2y antagonist. Acetylcholine (Ach)-induced relaxation was used in each experiment for control. RESULTS: In human precontracted corporal cavernosal strips with a functional endothelium (relaxed by acetylcholine) ADPbetaS induces a dose-dependent relaxation with maximal relaxation of 45.5+/-5.0% and an EC50 of 11.7 microM. The relaxant effect of ADPbetaS was reduced by 77.1+/-7.0% by reactive blue 2 (20 microM)(a P2y antagonist). L-NAME (L-Nitro Arginin Methyl Ester), an NO synthase inhibitor (100 microM), reduced Ach- and ADPbetaS- induced relaxations by 86.59+/-3.24% and 86.83+/-0.5% respectively. Ach- and ADPbetaS- induced relaxations were significantly inhibited after dislodging of the endothelial lining of the corporal cavernosal strips, 90.11+/-6.2% and 87.1+/-5% respectively. CONCLUSIONS: Human corporal cavernosal strips can be relaxed by stimulation of P2y purinoceptors via NO release. This relaxation is an endothelium-dependent mechanism. Purines may be implicated in physiological erection in man.

Adenosine Diphosphate↗
PubMed1999

Long-term incidence of acute myocardial infarction after open and transurethral resection of the prostate for benign prostatic hyperplasia.

PURPOSE: Acute myocardial infarction was found to be the main cause of increased long-term mortality in patients after transurethral compared to open prostatectomy in various retrospective studies. We performed a randomized prospective study to compare morbidity and incidence of acute myocardial infarction in patients after transurethral compared to open prostatectomy for benign prostatic hyperplasia. MATERIALS AND METHODS: We studied 365 patients who were assigned to transurethral (236) or open (129) prostatectomy only according to the size of the prostate and who were followed for 7 to 8 years. The clinical status of the patients in both groups before and after the operation was compared, and the rate of myocardial infarction and long-term mortality was studied. RESULTS: More patients with a history of cerebrovascular accident (5.4 versus 0.8%) and indwelling catheters (16.3 versus 7.6%) before the operation were in the open prostatectomy group. Among the 236 patients operated on transurethrally 31 were reoperated on (6 more than once) during followup compared to 4 of the 129 patients who underwent open prostatectomy. In 15 patients from the transurethral prostatectomy group myocardial infarction developed compared to 9 patients in the open prostatectomy group. This difference was not statistically significant. The rate of acute myocardial infarction after prostatectomy, no matter which approach was used, was greater than 6% and it appeared to be higher when compared to the rate of infarction in the general population of the same age group, which is approximately 2.5% in our county. There was no statistically significant difference in the overall mortality rate between the transurethral and open prostatectomy groups, which was 14.4 and 8.5% respectively. CONCLUSIONS: Open prostatectomy is more effective in overcoming urinary obstruction than the transurethral approach. No significant differences in myocardial infarction or overall mortality rates were found between the 2 groups.

Aged↗
PubMed1998

Chemopreventive effect of aspirin on growth of aberrant crypt foci in rats.

Nonsteroidal anti-inflammatory drugs display a chemopreventive effect on polyps and cancer of the large bowel. This study evaluated the inhibitory effect of aspirin on the distribution and growth of aberrant crypt foci (ACF), the earliest putative preneoplastic and early neoplastic lesions in a rat model. For initiation of ACF, Sprague Dawley rats were injected with azoxymethane (30 mg/kg), a well-established rat carcinogen. After the second injection the rats were allocated to three groups, which received 0.2% or 0.6% aspirin or the solvent only (control group). After 6 weeks the animals were killed, and their colons removed, fixed in formalin, and screened for distribution and size of ACF, separately for middle and distal parts of the large intestine. The rats injected with azoxymethane showed a 100% incidence of ACF. Administration of 0.2% and 0.6% aspirin resulted in 55% and 54% reduction, respectively, in overall frequency of ACF. Aspirin significantly reduced the frequency of medium-sized (four to six crypts per focus) and large (three to six crypts per focus) but not the small (one to three crypts per focus) ACF. In the control group the ACF of the same multiplicity were larger than those in the aspirin-treated rats. No statistically significant difference in ACF-inhibiting effect was noted between 0.6% and 0.2% aspirin solution. Aspirin given at a concentration of either 0.2% of 0.6% thus has a chemopreventive effect on ACF, acting on postinitiation stage of azoxymethane-induced colonic carcinogenesis model in rats.

Animals↗
PubMed1998

Bupivacaine infiltration into the neurovascular bundle of the prostatic nerve does not improve postoperative pain or recovery following transvesical prostatectomy.

PURPOSE: We assessed the effect of intraoperative bupivacaine infiltration into the neurovascular bundle of the prostatic nerve on postoperative pain and patient outcome. MATERIALS AND METHODS: The study included 40 American Society of Anesthesiologists physical status I to III patients undergoing transvesical prostatectomy. Following surgical resection of the prostate the neurovascular bundle of the prostatic nerve was infiltrated with either 10 ml. bupivacaine 0.5% or saline. Postoperative pain intensity was assessed using a patient generated 100 mm. visual analog scale and a patient controlled analgesia device. Additional analgesic requirements, time to ambulation, length of hospitalization and return to normal activity were also recorded. RESULTS: There were no differences in visual analog scale for pain, patient controlled analgesia demands or actual morphine delivered. Similarly, saline versus bupivacaine infiltration did not influence ambulation time (21.3 +/- 2.7 versus 25.0 +/- 11.8 hours, respectively), length of hospitalization (7.06 +/- 0.8 versus 7.11 +/- 0.6 days, respectively), return to normal activity (14.4 +/- 8.8 versus 14.2 +/- 8.2 days, respectively) or patient satisfaction. On postoperative days 1 and 2 more patients in the saline treatment group requested additional oral analgesia compared to the bupivacaine treatment group. However, no statistical difference was demonstrated. CONCLUSIONS: Following transvesical prostatectomy, prostatic nerve blockade has no beneficial effects on postoperative pain or patient outcome.

Aged↗
PubMed1998

Does the narrow operating field in perineal radical prostatectomy lead to more positive surgical margins?

AIMS: To assess the risk of leaving cancer-positive surgical margins in the perineal approach for radical prostatectomy as compared to the retropubic approach. METHODS: Seventy-six patients with clinically organ-confined prostate cancer (stage T1-2 NoMo) underwent radical prostatectomy. The 57 patients who underwent retropubic prostatectomy were compared to 19 patients in whom the perineal approach was undertaken. The two groups were compared for pre-operative PSA levels, clinical stage, biopsy Gleasson score, and any correlation between pre- and post-operative stage and grade of the disease and rate of cancer-positive surgical margins. RESULTS: Although there were no significant differences in the rate of organ-confined diseases and specimen Gleasson score in the two groups, the rate of positive surgical margins in the perineal approach was significantly lower (15.7 vs 29.8%) and the rate of extracapsular disease with negative margins was significantly higher (15.7 vs 7%). CONCLUSIONS: The narrow surgical field in the perineal approach for radical prostatectomy does not pose a higher risk for positive surgical margins and it might be the procedure of choice in stage T1C prostate cancer with a Gleasson score of below 7.

Aged↗
PubMed1998

The induction, maintenance, and recovery characteristics of spinal versus general anesthesia in elderly patients.

STUDY OBJECTIVE: To compare the induction and recovery profiles of three combinations of general anesthesia when used as an alternative to spinal anesthesia for elderly patients. DESIGN: Randomized, prospective, open-label study. SETTING: Large referral hospital. PATIENTS: 100 [ASA physical status I, II, and III] patients over 60 years of age undergoing brief transurethral surgery. INTERVENTIONS: In Groups Propofol-Propofol (P-P), Propofol-Isoflurane (P-I), and Propofol-Desflurane (P-D), anesthesia was induced with fentanyl (1 to 2 micrograms/kg i.v.) and propofol (1.0 to 2.0 mg/kg i.v.) and maintained with 70% nitrous oxide in oxygen and either a propofol infusion (75 to 150 micrograms/kg/min) or isoflurane (end-tidal 0.7% to 1.2%) or desflurane (end-tidal 1% to 4%), respectively. After induction, a laryngeal mask airway was placed and spontaneous ventilation was maintained. In Group Spinal (S), 1.5 ml 4% lidocaine (60 mg), in an equal volume of 10% dextrose, was administered intrathecally. MEASUREMENTS AND MAIN RESULTS: Induction and recovery characteristics were compared. Induction with propofol was technically easier and significantly (medp < 0.0001) faster (4.6 +/- 1.7 min, 4.7 +/- 2.2 min, and 3.8 +/- 1.4 min for Groups P-P, P-I, and P-D, respectively) than induction of spinal anesthesia (9.3 +/- 3.4 min). During the induction period, mean arterial blood pressure and heart rate were significantly higher in Group S. Emergence, extubation, and orientation times were similar among the general anesthesia treatment groups. In Group S, patient-generated pain scores were lower (p < 0.05) and recovery room admission longer (p < 0.001). Time to return to baseline digit symbol substitution test (DSST) scores was marginally improved in Groups P-P and P-D when compared to Group P-I. Postoperative nausea, sleepiness, anxiety, and coordination were unaffected by the treatment modality. CONCLUSION: General anesthesia with propofol and desflurane facilitates shorter induction and recovery times without adversely affecting patient comfort. Therefore, this technique may be preferable to spinal anesthesia for elderly patients undergoing short transurethral surgical procedures.

Aged↗
PubMed1998

Effect of exogenous adenosine and its monophosphate on the contractile response to acetylcholine in the human isolated detrusor muscle strips.

1. Adenosine (0.1-1 mM) or its 5'-monophosphate (5'-AMP) induced a concentration-dependent relaxation of tension caused by acetylcholine (0.2 microM) in human urinary bladder detrusor strips. 2. This effect was antagonized concentration dependently by theophylline at an apparent pA2 value of about 5. 3. Maximum relaxation by adenosine or 5'-AMP never exceeded 50% and 80%, respectively, of acetylcholine-induced tension. Relaxation by some beta2-adrenoceptor agonists (0.1-0.2 mM) or norepinephrine was limited to about 50% of maximum. 4. The responses to adenosine and terbutaline were additive, causing full relaxation, and suggesting mobilization of distinct mechanisms underlying muscle relaxation.

Acetylcholine↗
PubMed1997

Polyurethane stent for treatment of urethral strictures.

The use of stents in the treatment of urethral strictures is offered as an alternative to repeated internal urethrotomies, urethral dilations, and urethroplasties. We report our experience in 42 patients with bulbar and membranous strictures (33 and 9 patients, respectively). In 10 patients, the stent was removed after 3 to 5 months, and the treatment was curative in 4 patients in this group. In 16 patients, the stent was removed after 12 months, and in 6 it was removed after 24 months. Thirty-two patients voided satisfactorily after stent insertion. The stent did not prevent recurrent strictures after its removal in most of the patients, but if changed regularly, once a year, it may avert repeated urethrotomies, dilations, and urethroplasties, which makes it a valid alternative in elderly patients.

Adult↗
PubMed1996

A case of myospherulosis occurring in the perirenal adipose tissue.

The authors report a case of spontaneous myospherulosis that developed in the right perirenal adipose tissue, presented like an abscess, in an 82-year old man of the A, Rh+ blood group. The patient had a history of chronic lymphocytic leukaemia. Fine needle aspiration and histological examination of the renal cyst allowed the observation of 4- to 7-micron spherules (or endobodies) enclosed in saccular structures (or parent bodies) and accompanied by a foreign body-type response. The walls of the parent bodies were negative for PAS, Gomori's methenamine silver and Giemsa's stain. Immunohistochemical study was positive with anti A antibody specific of A1/A2 blood group and with anti glycophorin A antibody. The authors reviewed the literature concerning this rare lesion: it usually occurs in subcutaneous fat or in the paranasal sinuses, nose and middle ear but, up to now, no previous case has ever been reported in the urinary tract. The only case of visceral myospherulosis previously reported occurred in a cystic teratoma of the ovary. The reported case is also peculiar by the unusual thickness of the parent bodies. The authors also discuss the mechanism of the disease and suggest that, in the present observation, myospherulosis could have been induced by the rupture of a preexisting cyst in the perirenal adipose tissue.

Adipose Tissue↗
PubMed1996

Use of an intraurethral catheter instead of a Foley catheter after laser treatment of benign prostatic hyperplasia.

OBJECTIVE: Our study describes the results obtained in 15 patients in whom an intraurethral catheter (IUC) instead of an indwelling catheter was used after visual laser ablation of the prostate (VLAP). METHODS: The 15 patients were treated by VLAP for benign prostatic hyperplasia. The IUC was inserted through the cytoscope sheath immediately after completion of surgery, and left in the prostatic urethra for 3 weeks. RESULTS: Twelve of the 15 patients (80%) voided through the urethra without need of an indwelling catheter. In the remaining 3 patients the IUC had to be removed and a Foley catheter inserted. CONCLUSION: Our results reveal that the IUC stent may be used as an alternative for an indwelling catheter in patients treated by VLAP.

Aged↗
PubMed1996

Correction of congenital or acquired penile curvature through a simple corporoplication technique.

Sexual dysfunction resulting from penile deformity is amenable to surgical correction. Thirty-five cases of penile deformity either 29 congenital or six secondary to Peyronie's disease were treated by simple plication of the tunica albuginea with non-absorbable sutures through a small skin incision made on the convex side of the curved penis. Postoperative complications such as impaired erection or loss of sensitivity of the glans were not reported. After an average follow-up of 36 months (range 12-60 months) all patients have straight erections and retain normal erectile function.

Adolescent↗
PubMed1995

Is ipsilateral adrenalectomy a necessary component of radical nephrectomy?

Due to the increased use of modern imaging systems during the last few years, kidney tumors are often diagnosed at an earlier and less advanced stage. This fact implies a reevaluation of the operative technique of radical nephrectomy that was recommended 30 years ago. The ipsilateral adrenal involvement during radical nephrectomy for renal cell carcinoma is assessed and the necessity of its extirpation is discussed. Between September 1987 and September 1993, we performed 299 radical nephrectomies for renal cell carcinoma and removed 285 ipsilateral adrenal glands. Eleven adrenal glands (3.8%) were involved with the kidney tumor and 274 (96.2%) were free of disease. In 7 of the adrenal gland involved cases (63.6%) the tumor invaded the gland by direct extension from the superior pole of the kidney. In the other 4 cases the ipsilateral adrenal gland was affected by a metastatic lesion. In all 11 adrenal gland involved cases the tumors were at an advanced stage (the lowest was stage pT3N1). Our results led us to recommend adrenalectomy during radical nephrectomy only when direct extension of the kidney tumor into the gland is suspected (upper pole or large tumors) or when the adrenal is the site of a single metastasis. Macroscopically normal adrenal glands at radical nephrectomy should not be routinely extirpated. Metastatic renal cell carcinoma (not by contiguity) in the ipsilateral adrenal gland should be regarded as a stage M+ (distant metastasis) tumor.

Adrenal Gland Neoplasms↗
PubMed1993

Does detubularization improve continence in bladder replacement?

Camey in the seventies promoted bladder replacement. In 1987, the French Association of Urology gave us the opportunity to review 729 Tubularized Ileocystoplasty (Camey operation) [1]. The day time continence was excellent or acceptable (mild stress incontinence) on 91% of the patients, the night time continence was excellent (no pads, no leakage) or acceptable (one pad or less than 3 wakes at night) for 44% of the patients (56% had to use a device). Since 1985, the detubularization attempted to improve the continence rate. Today, the review of the literature shows that day time continence has not changed and the night time continence improved less than 20% arising from 44% to 60%. Bladder replacement after prostatocystectomy has been proved to be superior to continent urinary diversion in patients whose urethral and external sphincter can be preserved. Day time continence is excellent in tubularized and detubularized bowel reservoirs. Night time continence, in 30 to 50% of patients, remains an unresolved problem also in detubularized low pressure reservoirs, even if they are of great capacity. The literature is therefore too optimistic when describing night time continence in 85% of the patients. These results are stated in spite of the absence of sensitivity in the neobladder, the loss of reflexic increase in sphincteric activity during bladder filling, and the low sphincteric tonus during sleeping. These optimistic results are due to lack of unanimous criteria for evaluating continence after bladder replacement and not taking into consideration as continence failure the abundant although not frequent nighttime incontinence. In order to improve continence, muscle reeducation and artificial sphincter implantation are the most adequate solutions.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1992

Use of computerized interactive morphometry in the diagnosis of mammary adenoma and adenocarcinoma in dogs.

We attempted to define quantitative objective criteria for diagnosis of mammary adenoma and adenocarcinoma in dogs. To that end, correlation between diagnosis made by conventional histologic examination and morphometric descriptors, obtained by computerized histologic analysis, was assessed in biopsy specimens of mammary tissue from 63 dogs. We used 2 interactive computer procedures: one assessed mean nuclear perimeter, mean nuclear area, and circularity factor; and the other evaluated nuclear stratification and cell crowding. A data base was generated with 11 specimens from normal mammary tissue, 17 specimens from mammary adenoma, 18 specimens from low-grade mammary adenocarcinoma, and 15 specimens from mammary adenocarcinoma. The mean values of nuclear perimeter, nuclear area, nuclei per millimeter of basement membrane, and minimal distances from cells to basement membrane gradually increased from normal to high-grade malignancy. Distributions of nuclear areas and of minimal distances from cells to basement membrane were shifted in specimens from malignant tumors. Multivariate analysis confirmed the homogeneity of the diagnostic groups.

Adenocarcinoma↗