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Biomedical subjects

M M Hassouna

Publications and source records attributed to M M Hassouna.

29 records · Page 2Linked to original sources
PubMed1995

Apomorphine versus mating behavior in testing erectile capabilities of diabetic rats.

OBJECTIVES: Diabetes mellitus (DM) is an important cause of organic impotence. It is estimated that 35% to 75% of diabetic patients are impotent. In the present study we investigated the effect of experimentally induced diabetes (streptozocin 60 mg/kg, intraperitoneally, for 9 weeks) on sexual behavior and compared it to the apomorphine (APO) bioassay test. METHODS: Libido, genital reflex excitability, and penile competence as measured by different parameters of mating behavior were reduced with DM (P < 0.05 versus control for each parameter). RESULTS: Of 17 diabetic rats, 53% (9 rats) experienced positive mating behavior (either intromission or ejaculation) compared with 82.4% (14 rats) positive response to the APO bioassay test. Moreover, combined apomorphine injection and mating sexual testing in diabetic rats that achieved intromission but not ejaculation or those that did not achieve intromission in the initial mating, considerably improved the performance of these rats. CONCLUSIONS: We suggest that the APO test alone or, even better, combined APO injection and sexual testing are superior in eliciting maximum erectile capabilities of the diabetic rats than mating testing alone.

Animals↗
PubMed1995

Diabetes mellitus increases nitric oxide synthase in penises but not in major pelvic ganglia of rats.

OBJECTIVE: To determine the effect of diabetes mellitus (DM) on erectile function and evaluate the levels of nitric oxide synthetase (NOS) activity in streptozotocin-induced diabetic rats. MATERIALS AND METHODS: Rats were studied at 9 weeks and 14 weeks after the induction of DM by streptozotocin and compared with untreated control rats. Erectile potency was assessed physiologically by testing and recording mating behaviour. NOS activity was assayed in penile tissues and major pelvic ganglia (MPG) by conversion of [3H] L-arginine to [3H] citrulline. Histological, ultrastructural and immunohistochemical studies of penile tissues were performed in similar groups of rats. RESULTS: Diabetes mellitus adversely and significantly degraded all parameters of mating behaviour, thus indicating defective erectile potency. However, NOS activities in penile tissues from both groups of diabetic rats were significantly higher than those in controls (P < 0.01). In MPG, NOS activities were not significantly different between diabetic and control rats (P > 0.05). Histological, ultrastructural and immunohistochemical studies of penile tissues revealed no significant differences between control and diabetic rats, indicating an intact effector organ (smooth muscles) in rats with up to 14 weeks of DM. CONCLUSION: The impotence frequently observed in diabetic subjects would suggest that despite the increase in NOS activity in the penis, the pharmacological action of nitric oxide is impaired.

Amino Acid Oxidoreductases↗
PubMed1995

Long-term results of penile venous ligation for corporeal venous occlusive dysfunction.

OBJECTIVE: To evaluate the long-term results of penile venous ligation in patients with erectile dysfunction due to venous incompetence of the corpora cavernosa. DESIGN: A retrospective case study with follow-up longer than 22 months. SETTING: A university teaching hospital. PATIENTS: Thirty-two men with penile corporeal dysfunction, ranging in age from 33 to 77 years (mean 45 years). The duration of impotence ranged from 8 to 66 months (mean 29 months). The results were evaluated by chart review and patient questionnaire. INTERVENTION: Ligation of the penile cavernosal and crural veins. MAIN OUTCOME MEASURES: Penile-brachial index (PBI), peak flow rate in the cavernosal arteries after injection of papaverine, penile rigidity and maintenance of perfusion rate during cavernosometry, all measured preoperatively and compared postoperatively, and major venous leakage, defined as leakage into both the deep and the intermediate systems. RESULTS: Ten (31%) of the 32 patients had a good result (full rigid erection without adjuvant therapy postoperatively) and 9 (28%) showed improvement (full erection with intracorporeal injection). Of the 13 (41%) failures, 7 had temporary improvement, ranging from 6 to 20 months. Preoperative penile rigidity, PBI and peak blood-flow velocity were significantly higher in patients with good results than in those with poor results (68% versus 40%, p < 0.05). Major venous leakage occurred in 12 of 13 patients with poor results but in only 1 of the patients with good results. CONCLUSIONS: The success or failure of penile venous ligation should not be evaluated during the 1st year after the procedure. The presence of minor leakage and penile rigidity greater than 60% are good predictors of the success of the procedure.

Adult↗
PubMed1994

Neural stimulation for chronic voiding dysfunctions.

Neural stimulation of the sacral nerve roots could become an acceptable and promising modality in controlling variable forms of difficult voiding dysfunctions. A total of 50 patients who presented with various forms of voiding dysfunction underwent initial screening by percutaneous nerve evaluation of the S3 nerve root guided by movements of the levator ani and toes. Only 17 patients demonstrated a satisfactory response to percutaneous nerve evaluation and subsequent subchronic wire testing for 4 to 5 days, and they were eligible to enter the study. The studied patients (13 women and 4 men) were classified into 2 groups according to presentation. Group 1 included 8 patients who presented mainly with nonobstructive chronic urinary retention. All 8 patients were on intermittent self-catheterization except 1 with a suprapubic tube. The 9 patients in group 2 mainly presented with other forms of voiding dysfunctions, including pain (suprapubic and perineal), frequency and/or urgency. All patients were neurologically free, and had failed pharmacological and surgical attempts to correct the problems. In both groups radiological and ultrasound evaluations of the urinary tract as well as cystourethroscopy were within normal limits. Urodynamic studies were performed preoperatively and postoperatively. Unilateral S3 foramen implantation was performed on the selected side in all patients. Followup ranged from 3 to 52 months. All patients were followed preoperatively and postoperatively by voiding and itemized symptom score diary as well as a quality of life questionnaire. Each symptom and question were given certain grades that reflect the severity or importance to the patient. The symptom scores and the quality of life questionnaires were analyzed preoperatively and postoperatively. In group 1 voided volume (expressed as a percentage of total bladder capacity) was significantly increased at 6 months (23 +/- 7.5% preoperatively versus 81.9 +/- 7.7% postoperatively, p < 0.05) and, accordingly, residual volume (also expressed as a percentage of total bladder capacity) was significantly decreased. The maximum flow rate increased to 18.0 +/- 2.6 ml. per second postoperatively compared to 7.8 +/- 3.1 ml. per second preoperatively. The number of intermittent self-catheterizations per day decreased to 1.3 +/- 0.8 compared to 4.2 +/- 0.6 preoperatively (p < 0.05). Uninhibited bladder contractions with vesicosphincteric dyssynergia disappeared in 1 patient, while they persisted in 1 for up to 6 months. In group 2 the average improvement in pain and difficulty to start voiding was 85%, frequency improved by 37%, urgency by 42%, and leaking episodes and number of diapers per day decreased by 50%. Uninhibited bladder contractions disappeared in 1 patient within 6 months.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Effects of verapamil, prostaglandin F2 alpha, phenylephrine, and noradrenaline on upper urinary tract dynamics.

OBJECTIVES: The effects of verapamil (VRP), prostaglandin F2 alpha (PGF2 alpha), phenylephrine, and noradrenaline on upper urinary tract dynamics were studied in vivo, using a pig model involving 12 miniswine which were subjected to acute pharmacologic perfusion studies of the upper urinary tract. METHOD: Changes in renal pelvic pressure (Ppvs) and ureteral peristalsis frequency were recorded at 2 mL/min perfusion rate premedication, and then during perfusion with different concentrations of each drug tested in three experiments. RESULTS: Ppvs showed no significant variations with VRP perfusion when compared with premedication readings, whereas ureteral peristalsis frequency was decreased significantly by 10(-3) mol/L of VRP. PGF2 alpha perfusion caused no statistically significant changes in Ppvs when compared with premedication values, but increased ureteral peristalsis frequency from 3 to 6.5/min at a concentration of 2 x 10(-1) mg (200 micrograms). Phenylephrine HCl and noradrenaline perfusion increased Ppvs from 8 +/- 1.1 to 11.9 +/- 1.6 cm water at a concentration of 100 micrograms. They augmented the frequency of ureteral peristalsis from about 2.5 +/- 1.2 to 4.1 +/- 1.3/min. No systemic effects were recorded since pulse, respiration, and left ureteral activity were unchanged during pharmacologic perfusion of the right side. CONCLUSION: Pharmacologic manipulation of ureteral activity can be achieved via direct perfusion with no significant modulation of Ppvs or systemic impact. VRP-induced smooth muscle relaxation of the upper urinary tract may be useful in percutaneous surgery for stones.

Animals↗
PubMed1993

Healing and muscular restoration of the ureteral wall following balloon-induced rupture: an experimental animal model with light microscopic and ultrastructural observations.

Ureteral regrowth following balloon-induced rupture was studied using an animal model, with emphasis on the pattern and cellular events of self-reconstitution in the late phase of healing. At 4 weeks, the ureteral healing/remodeled region included a wedge-shaped muscular component which pointed toward a fibrous central zone, was continuous with the adjacent muscularis propria, and abutted on a thin-lining epithelium. Progressive enlargement, aggregation, and bundle formation of myogenic cells was observed along the centrifugal axis. At 7 weeks, there was near-total muscular continuity, a rudimentary lamina propria, and partial periluminal folding. Muscular restoration was unaffected by the use of a stent, but epithelial metaplastic changes were observed. The intermediate zone showed admixed fibroblasts, immature and mature myogenic cells, and myofibroblasts. Frequent plasmalemmal appositions and junctions were observed between different cell types, whereas myofibroblasts were not associated with cell-to-stroma attachments. Myofibroblasts might play more than a contractile role in this phase of ureteral healing, possibly having an induction role and/or representing a transient form in myogenic differentiation.

Animals↗
PubMed1993

Long-term effects of ureteric stent after ureteric dilation.

Balloon dilation of the right ureterovesical junction (UVJ) and distal ureter to three times its normal caliber was performed in 12 pigs. A right double-J (D-J) stent was inserted after dilation in 6 pigs. Bilateral upper tract dynamics with different perfusion rates (0.5, 2 and 4 ml. per minute) were recorded before dilation, immediately after dilation, and then 4 and 7 weeks after dilation. Immediate and late antegrade nephrostograms as well as suprapubic cystograms were taken. Grade 3 reflux occurred in 100% of animals at 7 weeks on the dilated, stented ureter and no reflux on the dilated, nonstented ureter. At 7 weeks on the dilated, stented side, significant growth (> 100,000, colonies) of Pseudomonas species was noted in all animals. Creatinine clearance was significantly reduced on the dilated, stented side when compared to the dilated, nonstented side at 7 weeks. Histologic examination of the dilated, stented and dilated, nonstented ureters at 4 weeks revealed a segmental muscular defect with muscular regeneration starting from the edge of the defect, particularly in the innermost region. At 7 weeks, there was a more advanced, but similar, pattern of muscular regeneration in both groups. However, at 7 weeks, metaplastic changes of the ureter and chronic pyelonephritis were evident on the dilated, stented ureter. Electron microscopy showed that myofibroblasts played a major role in the healing process with new muscle formation. At 4 weeks, no significant morphologic difference was found between the dilated, stented and dilated, nonstented ureters. At 7 weeks, however, it appeared that the ureteric stent resulted in damage and deterioration of renal function without affecting muscular regeneration of the ureter. We conclude that the changes observed could be entirely due to the infection associated with the stent rather the stent itself.

Animals↗
PubMed1993

The effect of diabetes on sexual behavior and reproductive tract function in male rats.

The effect of streptozotocin induced diabetes and sabeluzole (SBZ) on sexual function was evaluated in male rats. SBZ is a benzothiazole derivative with antihypoxic and antiischaemic activities. Rats were rendered diabetic by intraperitoneal injection of streptozotocin, 60 mg./kg. body weight, and either left untreated or treated with 1.0 mg./kg. of SBZ. Two groups of control rats treated with or without SBZ were also evaluated. Seven weeks after the induction of diabetes, all rats were studied in vivo for mating behavior. Animals were sacrificed one week later, and detrusor strip response in vitro was evaluated. The reproductive organ weight, sperm content and motility as well as in vitro testosterone secretion and serum levels of LH and testosterone were determined. Diabetes induced significant reduction in mating behavior. The diabetic rats that received SBZ showed a significant improvement in mating behavior. The percentage of animals that exhibited ejaculation was 0% in the diabetic group compared to 70% in the controls and 38% in diabetic plus SBZ group. The strips of the detrusor muscle of the diabetic group showed a marked hypersensitivity to bethanechol HCL. In the diabetic plus SBZ group, the strips of the detrusor muscle showed a response similar to that of the control. The diabetic rats had significantly diminished reproductive organ weight, testicular sperm content, epididymal sperm content and sperm motility relative to the control. In addition, marked decrease in the serum level of testosterone and in vitro testosterone secretion was observed in diabetic rats. In the diabetic plus SBZ group, the reproductive organ weight, sperm content and motility as well as serum testosterone and in vitro testosterone secretion showed an improvement compared to diabetic rats. In summary, our data suggest that sex behavior and reproductive tract functions are markedly affected by streptozotocin induced diabetes. Sabeluzole treatment could be beneficial in reducing the deleterious effect of diabetes on sexual functions.

Animals↗
PubMed1992

Computerized transcutaneous control of a multichannel implantable urinary prosthesis.

In the present paper we describe a personal computer interface of a multichannel implantable urinary prosthesis. This system is composed of two main parts: the first one is internal and consists of an implant using a 4-microns CMOS gate array chip controlling a wide variety of waveforms via eight monopolar channels. The second, an external controller featuring a versatile software, a PCB card plugged in a portable microcomputer, and a radiofrequency-coupled technique. This device is used to transmit the power, the data and the synchronization clock to the implant by a simple binary signal modulating a 20 MHz carrier. We also report the features of implant encapsulation and electrode design and fabrication. In the experimental phase, we studied the effect of early electric stimulation of the bladder during the spinal shock phase in the dog. We present the operative techniques that enabled us to perform chronic electrostimulation of the sacral roots and discuss the results.

Animals↗
PubMed1988

The evolution of artificial sphincter cuff in growing animals.

An animal model was developed to simulate the effect of implantation of artificial sphincter cuff on the urethra in children. The study was conducted on 28 pigs, 15 castrated males, four uncastrated males and nine females, divided into four groups: control unoperated, and three operated groups. Group I contained young piglets (castrated males, uncastrated males and females), group II contained adult animals and group III contained sham operated animals. An AS 800 belt occlusion cuff was implanted in the deflated state distal to the bladder neck around the urethra in the young and adult groups, while no sphincter was implanted in the sham group. Neither primary nor secondary activation was done. The pigs were followed for a period of six to eight weeks and then sacrificed. The morphological and histological observations on the effects of the artificial sphincter cuff on the underlying urethral tissue showed significant transmural atrophy of the urethral and prostatic segment underlying the cuff in the young growing castrated and uncastrated male group with mild changes in the young female group. Bladder rupture occurred in three uncastrated males. There were no changes encountered in the adult or sham operated groups. Variable degrees of upper tract changes and renal deterioration were seen in the young group. These changes occurred mainly in the male piglets while a lesser degree occurred in the female piglets. No changes were demonstrated in the adult and sham groups. This study suggests the possibility of similar changes occurring in young male children who have undergone artificial sphincter implantation.

Age Factors↗