Biomedical subjects

M A Sakr

Publications and source records attributed to M A Sakr.

3 recordsLinked to original sources

PubMed1997

Human vasal changes after vasectomy: in vitro studies.

UNLABELLED: Failure to impregnate, after successful vasovasostomy, has been attributed to immunologic, testicular, and epididymal factors. OBJECTIVES: To study the effect of vasectomy on human vas innervation and vesicoelastic properties. METHODS: Vas rings were obtained from 8 healthy males during vasectomy as controls and compared to those of 3 vasovasostomy patients. The active and passive properties were determined and the cumulative blocking effects of phenoxybenzamine, propranolol, atropine and tetrodotoxin were studied. RESULTS: There was significantly higher rigidity in the vasovasostomy group as compared to the control group but there were similar active forces between the two groups up to 100-120% of stretch. In the control group, phenoxybenzamine blocked 33.3%, propranolol blocked 15.8%, and atropine blocked 36.5% but tetrodotoxin had no further effect. In the vasovasostomy group, phenoxybenzamine blocked 33.3% (similar to control), propranolol blocked 2%, atropine blocked 11.7% and tetrodotoxin blocked 37.1%. CONCLUSIONS: In vasovasostomy group there was increased rigidity without reduction of the active force. There were also decreased cholinergic and possible existence of nonadrenergic noncholinergic neurotransmitters.

Adrenergic alpha-Antagonists↗

PubMed1997

A telemetric multichannel computer-based system for monitoring urodynamic parameters in awake rhesus monkeys.

For comprehensive telemetric monitoring of bladder function in monkeys, transducers were implanted in the bladder wall and abdominal cavity. The EMG lead was buried in the external sphincter. All wires terminated in a subcutaneous transmitter. Conventional urodynamics were performed for comparison. Excellent reproducibility with conventional urodynamics was found. Implantation caused detrusor instability, which subsided in 6 to 8 weeks. Real-time computer-based multichannel telemetric studies of voiding are feasible and reliable. Telemetric studies monitor for long periods without stress or anesthesia and provide an excellent model for lower urinary tract studies.

Animals↗

PubMed1996

Conventional, continuous, and telemetric monitoring of urodynamic parameters in non-human primates: a comparative study.

A comparison between three different techniques for monitoring urodynamic parameters in non-human primates was conducted in six adult female rhesus monkeys. This study was divided into two phases. In phase I, the animals were studied by conventional and continuous methods. During the study, uroflow and micturition pattern were obtained while the animals housed in a specially designed metabolic cage. Pressure transducers and EMG electrodes were surgically implanted. Then the animals were trained for 6 weeks to sit in a specially designed chair. Upon completion of the training period, continuous monitoring of the urodynamic parameters could be carried out for periods up to 14 hours. In phase II, the animals were studied with the conventional and telemetric methods. The same type of pressure transducers and EMG electrodes were implanted but they terminated in a radio transmitter powered by a long-life battery and controlled by a radio-operated switch. Conventional studies under ketamine sedation significantly increased bladder capacity, as well as the pressure at capacity (P < 0.05). Continuous monitoring was feasible, physiological, and more sensitive than the conventional techniques. Telemetric studies are superior to continuous monitoring, since the animal is not tethered to wires and provide data over a longer period of time. It is concluded that telemetric monitoring provides significantly different parameters, which could help in diagnosis and management of different voiding dysfunctions. In normal non-human primates, lower bladder capacity, higher maximum voiding pressure, higher bladder compliance, and higher incidence of detrusor instability without urethral relaxation were found. Telemetric urodynamic data on different pathological processes are currently unavailable and further work is needed in this area.

Animals↗