Biomedical subjects

A Shafik

Publications and source records attributed to A Shafik.

At least 163 records · Page 9Linked to original sources

PubMed1995

Laparoscopic cystomyotomy for bladder neck obstruction.

Laparoscopic cystomyotomy was used for the treatment of bladder neck obstruction in 18 male patients with a mean age of 36.4 +/- 10.4 (SD) years (range 22-43 years). Through an extraperitoneal laparoscopic approach, the bladder neck was exposed. A 1-in. linear incision was performed across the bladder neck, dividing the muscle coat but sparing the mucosa, which bulged through the gap. Patients were followed for a mean of 8.3 +/- 2.4 (SD) months (range 3-13 months). Improvement occurred in 16 patients (88.8%) and failure in 2 who had a calcified and contracted bilharzial bladder. No operative or postoperative complications were encountered. There was no retrograde ejaculation or restenosis. In conclusion, laparoscopic cystomyotomy is simple and easy with a short postsurgical recovery period.

Adult↗

PubMed1995

Recognition of a pharyngo-oesophageal sphincter inhibitory reflex in dogs and its role in deglutition.

The present study describes the 'pharyngo-oesophageal sphincter inhibitory reflex' and its clinical significance. The study was performed on twelve anaesthetized dogs. A balloon-tipped catheter was placed within the pharyngo-oesophageal sphincter (POS) and another in the pharynx. The POS response to distension of the pharynx with a balloon filled with 2, 4 or 6 ml of water was recorded before and after application of local anaesthetic to the POS, and after successive section of the anatomical constituents of the POS. Upon pharyngeal distension, POS pressure was reduced; the greater the distension, the greater the pressure reduction. The anaesthetized POS did not respond to pharyngeal distension. Section of the cricopharyngeus muscle did not influence the resting POS pressure or the POS response to pharyngeal distension. The POS pressure dropped significantly (P < 0.0001) and was unresponsive to pharyngeal distension after section of both the cricopharyngeus muscle and the oesophageal circular muscle bundles. This shows that the cricopharyngeus muscle is not involved in the upper oesophagus sphincter mechanism.

Animals↗

PubMed1995

Sacral root stimulation for controlled defecation.

Selective rectal or sphincter neurostimulation aiming at controlled defecation was performed in 10 dogs. While the dogs were under anesthesia, the rectal and rectal neck pressures, balloon expulsion as well as external anal sphincter (EAS) response to stimulation of the second sacral ventral nerve root (S2) and its autonomic and somatic branches were determined. Each of these nerves was stimulated separately using bipolar platinum cuff electrodes. S2 stimulation resulted in rectal and rectal neck pressure elevation as well as increase of EMG activity of EAS without balloon expulsion. Autonomic branch stimulation effected rectal pressure increase and balloon expulsion, while somatic branch stimulation caused increase of rectal neck pressure and EAS EMG activity with no balloon expulsion. S2 stimulation with somatic branch transection produced rectal pressure elevation and balloon expulsion. In contrast to rectal pressure, the rectal neck pressure increased with increasing stimulus frequency. In conclusion, rectal evacuation and sphincteric control could be induced by selective sacral root electrostimulation: S2 stimulation with transection of the somatic branch for the former and pudendal branch stimulation for the latter.

Anal Canal↗

PubMed1995

Transcutaneous electrorectography: human electrorectogram from surface electrodes.

The rectal electric activity or electrorectography was recorded transcutaneously in 24 healthy volunteers (mean age 39.6 years). A silver-silver chloride electrode was applied lateral to each of the two sacroiliac joints, and a third one was placed midway between the left greater trochanter and the ischial tuberosity. The reference electrode was applied to the right lower limb. At least two 20-min recording sessions were performed for each of the 24 subjects. In addition, an intrarectal electrorectographic recording was done in 10 of the 24 subjects using silver-silver chloride electrodes attached to the rectal mucosa by suction. Pacesetter potentials (PPs) were recorded transcutaneously. The wave was triphasic with a small positive, a large negative and another small positive deflection. PPs had a regular rhythm and were reproducible. The mean frequency was 3.1 cycles/min. The transcutaneously recorded PPs could be confirmed by the intrarectal route. Both routes had similar electrorectographic recordings, except for the action potentials (APs) which did not show in the transcutaneous electrorectogram. In conclusion, the study demonstrates that PPs could be recorded transcutaneously. Transcutaneous electrorectography is simple, easy, reproducible and cost-effective, and may prove to be a useful investigative tool in the diagnosis of anorectal disorders.

Action Potentials↗

PubMed1995

Electrovesicography in interstitial cystitis.

An electrovesicogram (EVG) was performed in 9 women (mean age 44.6 years) with interstitial cystitis (IC) to characterize an electrovesicographic pattern for diagnostic purposes. Seven healthy women acted as controls. One electrode was located above and lateral to each pubic tubercle and a 3rd above the symphysis pubis. A reference electrode was applied to the lower limb. Recording was done in both the full and empty urinary bladder. Pacesetter potentials (PPs) were registered in the normal women as triphasic waves which had the same frequency, amplitude and regular rhythm each time the test was repeated in the same subject. The EVG of the empty bladder was similar to that of the full one, except for the PP amplitude which was lower in the former. The EVG in IC patients showed a 'vesicoarrhythmic pattern' with an irregular rhythm and a higher frequency and amplitude than the controls. The same pattern was recorded in the empty bladder but with a PP amplitude lower than that of the full bladder and the controls. In conclusion, a vesicoarrhythmic electrographic pattern could be identified in IC that may act as an investigative tool in the diagnosis of such a condition. The technique is simple, easy, noninvasive and cost-effective.

Action Potentials↗

PubMed1995

The peno-motor reflex: study of the response of the puborectalis and levator ani muscles to glans penis stimulation.

The response of the pelvic floor muscles (puborectalis 'PR' and levator ani 'LA') as well as the vesical, prostatic urethral and anal pressures to glans penis 'GP' stimulation was determined aiming to elucidate their role in the sexual act. The study was done in 16 healthy volunteers (mean age 43.3 years). The GP was stimulated mechanically and electrically by surface electrode. The vesical and prostatic urethral pressures were measured with a two-channel microtip catheter and the anal pressure by a balloon-tipped catheter. The response of the PR and LA muscles to GP stimulation was determined by a needle electrode inserted into each of them. Upon electrical or mechanical stimulation of the GP, the vesical pressure showed significant drop (p < 0.05), whereas the prostatic urethral and anal pressures increased (p < 0.05). The EMG of the PR and LA muscles recorded significant increase (p < 0.01). The response was greater upon electrical than mechanical stimulation and was not evoked by stimulation of either the anesthetized GP or the PR and LA muscles. PR and LA contraction upon GP stimulation postulates a reflex relationship which we call 'peno-motor reflex'. The constancy of this reflex relationship is evidenced by reproducibility and by the failure to evoke the response when either of the two arms of the reflex arc was anesthetized. PR contraction is associated with contraction of external urethral, prostatic and anal sphincter which might explain the rise of prostatic urethral and anal pressures. It seems that during the sexual act urethral and anal sphincters' contraction prevents leak of urine or stools, while prostatic sphincter contraction squeezes the prostatic secretions into the posterior urethra.

Adult↗

PubMed1994

Study of the electromechanical activity of the urinary bladder. An experimental study.

The electromechanical activity of the urinary bladder (UB) was studied in 16 dogs. With the animals under anesthesia, the UB was exposed and four electrodes were sutured serially to its anterior wall. Electric activity simultaneously with vesical pressure was recorded for periods of 30 min daily on 10 days. Triphasic pacesetter potentials (PP) were registered from electrodes 1-4, having identical frequency and regular rhythm by all electrodes and being consistent in the individual dog on all test days. Action potentials (AP) followed PP randomly and were accompanied by vesical pressure increase; they represented vesical contractile waves. Balloon distension of the UB effected increased PP and AP frequency. Annular vesical myotomy led to PP and AP disappearance distal but not proximal to the myotomy, which would suggest that (a) the waves spread caudally and (b) a "pacemaker" exists at the upper part of the UB and triggers the PP.

Action Potentials↗

PubMed1994

Perineal nerve stimulation for urinary sphincter control. Experimental study.

The effect of electrostimulation of the perineal nerve on the external urethral sphincter (EUS) and urethral pressure was studied in 9 dogs. The nerve was displayed in the ischiorectal fossa through a para-anal incision and an electrode was applied to it. Perineal nerve stimulation effected an increase of the urethral pressure (P < 0.01) and EMG activity of the EUS (P < 0.01), but not of the vesical pressure (P > 0.05). The greater the stimulus frequency, the higher the rise of the urethral pressure and EUS activity up to 50 Hz beyond which no further increase occurred. The duration of response diminished with increased frequency, the shortest being at 80 Hz (P < 0.001). The latency of the response decreased with increased stimulus frequency (P < 0.05). In terms of force and speed of contraction, stimulus frequency of 50 Hz evokes the most adequate EUS contraction. An off-time of double the stimulation phase allows indefinite re-stimulation. Chronic electrostimulation of the perineal nerve may restore the sphincter tone so that perineal stimulation could be dispensed with.

Animals↗

PubMed1994

Prolactin injection, a new contraceptive method: experimental study.

"Prolactin injection" is presented as a new contraceptive method. The method was tested in dogs. The dogs in the test group were injected with prolactin (PRL) in a dose of 600 micrograms/kg of body weight weekly for 6 months. During this period, the testicles, semen, reproductive hormones, renal function, and serum sodium and potassium were examined periodically. Testicular biopsy was obtained after 3 and 6 months of PRL injection. These investigations were repeated during the 6 months following withdrawal of the drug. Sperm count decreased to azoospermia in 3 months after PRL administration with decrease of sperm motility and increase of abnormal forms. Testicular biopsy showed degenerated seminiferous tubules. Reproductive hormones, renal function, and serum sodium and potassium revealed insignificant change (P > 0.05). Dog mating during the period of PRL administration induced no pregnancy. After 3 months of drug withdrawal, the sperm count normalized and dog mating produced pregnancy; offsprings showed no anomalies. The study demonstrates that PRL administration has the potential to be developed as a reversible male contraceptive.

Analysis of Variance↗

PubMed1994

Ano-vesical reflex: role in inducing micturition in paraplegic patients.

The reflex relationship between the anal canal and the urinary bladder was investigated in 14 normal volunteers and in seven patients with spinal cord injury of more than 2 years duration. The latter induced urination by dilating the anal canal with the finger. The vesical pressure was measured by a balloon-tipped catheter introduced into the urinary bladder which was filled with 100 ml saline. The anal canal was inflated with a balloon catheter filled with 2 ml air; inflation was increased in increments of 2 ml up to 10 ml. The vesical pressure in response to both slow and rapid anal distension was recorded. The external and internal anal sphincters were blocked separately and the test was repeated. Rapid anal inflation elevated the vesical pressure. The greater the anal inflation, the higher the vesical pressure. Slow anal distension induced insignificant vesical pressure changes (p > 0.05). Rapid anal distension with internal sphincter block induced insignificant vesical pressure changes (p > 0.05) while the vesical pressure showed a significant increase with external sphincter block. In paraplegic subjects, the vesical pressure increased on rapid anal distension with 6 ml air but did not further increase with greater distension. Vesical pressure increase was recorded after external sphincter block but there was an insignificant change after internal sphincter paralysis. The aforementioned results were reproducible.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Extraperitoneal inguinal pelviscopy: diagnostic tool for nonpalpable testes.

In patients with nonpalpable testes, intraperitoneal laparoscopy is not a direct approach to the tissues in which the gonad is likely to be located. Accordingly, the technique may be time-consuming and accompanied by complications. In 23 patients, the retropubic space was insufflated with carbon dioxide through a suprapubic puncture, and a pelviscope was advanced beyond the deep inguinal ring into the extraperitoneal pelvic cavity using the vas deferens as a guide. The nonpalpable testis was located in all patients, being deep to the inguinal ring in 17 and in the iliac fossa in 4. In the two patients with bilateral nondescent, three testes were deep to the inguinal ring, and one was lying over the psoas muscle. No complications were encountered. Extraperitoneal pelviscopy is simple, easy, and safe and provides a direct approach to the pelvic and abdominal extraperitoneal tissues.

Adolescent↗

PubMed1994

Utero-cervical inhibitory reflex. The description of a reflex and its clinical significance.

The functional relationship of the uterine corpus to the cervix was studied in 14 healthy women. The uterus was stimulated by an electro-myographic (EMG) needle electrode and the cervical pressure recorded by a balloon-tipped catheter. The test was repeated in seven women after the uterus had been anaesthetized. In the other seven patients, the response of both the uterine EMG and pressure to cervical dilatation was registered. The EMG needle electrode was then inserted into the cervix and the uterine pressure response to both stimulation and dilatation of the non-anaesthetized and anaesthetized cervix was recorded. Uterine muscle stimulation led to a cervical pressure drop from a mean of 15.8 +/- 6.6 to 5.3 +/- 2.2 cm H2O (P < 0.01). The cervical pressure did not respond to stimulation of the anaesthetized uterus. Cervical dilatation caused increase of the uterine pressure from a mean of 16.2 +/- 5.2 to 42.8 +/- 10.5 cm H2O (P < 0.01), whereas cervical stimulation effected a uterine pressure drop to a mean of 3.6 +/- 1.8 cm H2O (P < 0.01). Stimulation or dilatation of the anaesthetized cervix did not cause uterine pressure changes. The invariable cervical dilatation upon uterine stimulation suggests a reflex relationship which we have named 'utero-cervical inhibitory reflex' (UCIR). It seems that the reflex comes into action during labour and in conditions of uterine retention of blood or a dead ovum. Its impairment may interfere with cervical dilatation or lead to cervical incompetence. The UCIR could be included as an investigative tool in utero-cervical disorders.

Adult↗

PubMed1994

Anal submucosal injection: methotrexate concentration in rectal tumor tissue and serum after anal compared with parenteral injection.

As the results of adjuvant chemotherapy in the treatment of advanced rectal cancer are unsatisfactory, more effective regimens and routes of administration are being tried. Submucosal anal injection of methotrexate (MXT) has given encouraging results in the treatment of pelvic malignancies. This communication studies the MXT level in serum and rectal cancer tissue after either anal submucosal or parenteral MXT administration. Twenty four patients, mean age 46.4 years (16 men and eight women), with stage C rectal cancer were divided into two equal, age- and sex-matched groups. MXT (50 mg) was administered to each patient intravenously in one group and into the anal submucosa in the other. A blood sample was taken 30, 60 and 120 min after injection, and again after 24 h. A tumor sample was also taken each 30 and 60 min of injection. The serum and tissue MXT levels were determined using a radioimmunoassay kit. The serum MXT concentration was significantly higher after parenteral than after anal injection. Meanwhile, the concentration of MXT in tumor tissue was higher after anal administration. In conclusion, the anal route of administration of MXT, by inducing a high MXT concentration in the tumor tissue associated with a low serum level, might achieve satisfactory therapeutic results in advanced rectal cancer, with minimal side effects.

Adult↗

PubMed1994

Study of the electrical and mechanical activity of the rectum: an experimental study.

The electrical activity of the rectal detrusor was studied in 13 dogs. 10 electrodes were sutured serially to the rectal and lower sigmoid colon serosa. Electrical activity was recorded for 30 min/day for 10 days. Simultaneous electric and mechanical activity (recorded by a 6-French catheter connected to a pressure transducer) was also recorded with and without rectal distension by a condom balloon. Electrical activity was further determined after annular myotomy performed at different levels in the rectum and lower sigmoid colon. Pacesetter potentials (PP) were recorded from electrodes 3-10. They were triphasic, propagated caudally and had the same frequency and regular rhythm by all electrodes distal to the 3rd one. Frequency was constant in each dog from day to day. PP were accompanied by action potentials (AP) which had inconsistent frequencies and were accompanied by increased rectal pressure. Rectal distension led to an increase in both the frequency and amplitude of PP and AP. Rectal myotomy below the 3rd electrode resulted in PP and AP disappearing distal but not proximal to the cut, excluding the 1st and 2nd electrodes, which did not show activity. The results suggest that PP start at the 3rd electrode, which corresponds anatomically to the rectosigmoid junction (RSJ). AP cause contractile activity along the rectum. It seems that the RSJ is the site of a pacemaker triggering the PP that pace the AP which initiate the rectal contractile activity.

Action Potentials↗

PubMed1994

Uterocervical reflex: description of the reflex and its clinical significance.

The effect of uterine distension on the cervix was studied in 16 women (mean age 38.4 years). Carbon dioxide was infused, in increments up to 50 ml, into a condom-ended catheter introduced into the uterus. The response of uterine and cervical pressures to uterine distension was determined before and after anesthetizing the uterine body and the cervix, respectively. Upon slow uterine distension, the cervical pressure increased (p < 0.01), while the uterine pressure showed insignificant changes (p > 0.05). Rapid distension led to cervical pressure decrease (p < 0.01) and increase of uterine pressure (p < 0.01). The cervical pressure did not respond to slow or rapid inflation of the anesthetized uterus, neither did the anesthetized cervix respond to uterine inflation. A reflex relationship seems to exist between the uterine body when distended and the cervix, which we call 'uterocervical reflex'. The study demonstrates that the uterus behaves differently under physiologic and pathologic conditions. Upon slow uterine distension as in pregnancy, the uterus adapts by uterine dilatation and cervical tightening. In pathologic conditions which distend the uterus rapidly, the latter reacts with uterine contraction and cervical dilatation, discharging the uterine contents. Dysfunction of the uterocervical reflex may result in uterine and cervical disorders. The reflex may thus be included as a diagnostic tool in such disorders.

Adult↗

PubMed1994

Cavernous nerve stimulation through an extrapelvic subpubic approach: role in penile erection.

The results of cavernous nerve (CN) stimulation through an extrapelvic subpubic approach in 12 dogs are presented. The nerve was exposed and identified by a magnifying loupe and electric stimulation. A bioplar platinum electrode was then applied to the nerve and a radiofrequency receiver implanted subcutaneously into the abdomen. The CN was stimulated (pulse width 200 microseconds, range density 2-6 microCi/cm2/phase) and the intracavernous pressure was recorded. CN stimulation led to intracavernous pressure increase. With increasing stimulus frequency, the pressure increased while the latency and stimulation phase decreased, until at 60 Hz frequency no further changes occurred. Increasing CN stimulation was accompanied by a progressive increase in penile length and diameter leading to full erection at a frequency of 60 Hz. The penile response was more rapid and of a shorter duration with stronger stimulation. CN stimulation could be repeated indefinitely without fatigue after an off-time of double the period of the stimulation phase. The extrapelvic subpubic approach to CN is simple and without complications, and can be applied safely in humans.

Animals↗

PubMed1993

The electrified catheter. Role in sterilizing urine and decreasing bacteriuria.

A catheter was designed to decrease the incidence of catheter-induced urinary infections. A randomized, controlled study was performed to assess its safety and efficacy. The study comprised 24 patients subjected to hemorrhoidectomy. The criteria for entry were a preoperative urinary pathogen count below 10(5) colony-forming units/ml urine as well as postoperative urinary retention that did not respond to conservative measures. The 24 patients were randomly assigned to treatment using a Nelaton catheter in 12 patients and an electrified catheter in the remaining 12. The catheters were left in place for 3 days, during which cephalosporin was given parenterally. The electrified catheter (EC) carried two silver-silver chloride electrodes. During the 3 days of catheterization and for 4 days thereafter, daily urine samples were cultured. The criterion for catheter-induced urinary infection was a pathogen count above 10(5) colony-forming units/ml urine. No complication was encountered from catheterization. Electrodes were not broken. A bacterial count above 10(5) colony-forming units was found in 7 of 12 patients in the Nelaton catheter group, and a count below 10(5) units was determined in the 12 patients in the EC group. The study demonstrated that the EC can decrease the incidence of catheter-induced urinary infections. The EC is safe, cost-effective, and without complications.

Bacteriuria↗

PubMed1993

Effect of different types of textile fabric on spermatogenesis: an experimental study.

The effect of different types of textile fabric on spermatogenesis was studied. Twenty-four dogs were divided into two equal groups, one of which wore cotton underpants and the other polyester ones. Seven dogs wearing nothing were used as controls. The underwear was fashioned to fit loosely in the scrotal area so as to avoid its insulating effect. It was worn continuously for 24 months during which the semen character, testicular temperature, hormones (serum testosterone, follicle stimulating hormone, luteinizing hormone, prolactin) and testicular biopsy were examined. The garment was then removed, and the same investigations repeated through another 12 months. The results were analysed statistically. In the polyester group the testicular temperature showed insignificant changes during the period when the pants were worn (P > 0.05). By the end of the 24 months there was a significant decrease in sperm count and motile sperms, with an increase in abnormal forms (P < 0.001); the testicular biopsy showed degenerative changes. After garment removal the semen character improved gradually to normal in 10 dogs; two remained oligozoospermic. There were insignificant changes (P > 0.05) in hormones during the study. In contrast, the cotton and control groups showed insignificant changes (P > 0.05) in all the aforementioned parameters during the 36 months of the study. The polyester pants thus had a deleterious effect on spermatogenesis in the dogs which was, however, reversible in the majority of cases. The cause of this effect is unknown, but it may be assumed that the electrostatic potentials generated by the polyester fabric play a role in it.

Animals↗