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Biomedical subjects

H Nasr

Publications and source records attributed to H Nasr.

11 recordsLinked to original sources
PubMed1997

5 alpha-reductase deficiency in patients with micropenis.

The enzyme 5 alpha-reductase (5 alpha R), by virtue of its peripheral 5 alpha-reduction of testosterone (T) to dihydrotestosterone (DHT), is believed to play a major role in the differentiation and the subsequent growth of the penis. However, recent studies have reported 5 alpha R deficiency (5 alpha RD) in patients with isolated micropenis and hypothesized that 5 alpha RD is not invariably associated with genital ambiguity. In Egypt, 5 alpha RD has been reported frequently among intersex patients. The aim of this study was to assess the role of 5 alpha RD in the development of micropenis among Egyptian patients with abnormal sexual development. The study included 29 patients who were categorized into three groups (isolated micropenis, 9 patients; microphallus with genital ambiguity, 11 patients; genital ambiguity with normal-sized phallus, 9 patients). Activity of 5 alpha R was assessed by estimating T/DHT ratios in the basal state in pubertal subjects and following human chorionic gonadotropin (HCG) stimulation test in prepubertals. The results showed that the incidence of 5 alpha RD was much higher in cases of ambiguous genitalia with micropenis (5 families out of 10, 50%) than in those with isolated microphallus (1/9, 11.1%) or those with ambiguous genitalia and normal-sized phallus (1/8, 12.5%). In conclusion, the study showed that isolated micropenis is a heterogeneous disorder and that 5 alpha RD, despite its relative prevalence in Egypt, has a minimal role in the aetiology. On the other hand, 5 alpha RD seems to correlate with penile length in intersex cases.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1997

Countertorque testing and histomorphometric analysis of various implant surfaces in canines: a pilot study.

As surface roughness may play a role in the mechanical attachment of an implant surface to bone, various implant surfaces have been prepared and analyzed by removal torque (countertorque) or push-out tests in a variety of animal model systems. Rougher surfaces generally have displayed higher mechanical testing values, indicating a stronger implant-bone interface. This pilot study was undertaken to test the countertorque values for integrated threaded implants with surfaces prepared by machining, blasting, and acid-etching, to compare the various implant surface types histomorphometrically for percentage of bone-implant contact under loaded and unloaded conditions, and to determine the degree of correlation between countertorque values and bone-implant contact with varying degrees of surface roughness. The results of this animal investigation suggest that the strength of the bone-implant interface, as determined by countertorque testing, is influenced by different surface characteristics. Acid-etched surfaces resisted countertorque forces more successfully as compared with blasted or machined surfaces. Histologic evaluation of bone contact with the various implant surfaces did not demonstrate a definite advantage for rougher surfaces in regard to percentage of bone contact at the light microscopic level.

Acid Etching, Dental↗
PubMed1990

Glucose and glutamine metabolism in the small intestine of septic rats.

The intestinal metabolism of glucose and glutamine was studied in rats made septic by cecal ligation and puncture technique. Sepsis resulted in negative nitrogen balance and produced increases in the concentrations of blood pyruvate, lactate, alanine, and glutamine, and decreases in those of 3-hydroxybutyrate and acetoacetate. Both plasma insulin and glucagon concentrations were increased by 2.2- and 3.2-fold in septic rats, respectively. Portal-drained visceral blood flow increased in septic rats, and was accompanied by a decrease in the rates of utilization of glutamine and production of lactate, glutamate, and ammonia compared with those rates in sham-operated animals. Enterocytes isolated from septic rats showed decreased rates of glucose and glutamine utilization compared with cells isolated from corresponding controls. The maximal activities of hexokinase, 6-phosphofructokinase, pyruvate kinase, and glutaminase were decreased in intestinal mucosal scrapings of septic rats. It is concluded that a moderate form of sepsis decreases the rates of glucose and glutamine utilization (both in vivo and in vitro) by the epithelial cells of the small intestine. This may be caused by changes in the maximal activities of key enzymes in the pathways of glucose and glutamine metabolism in these cells as a metabolic adaptation to spare glucose and glutamine for use by other tissues.

Animals↗
PubMed1982

Electroconvulsive therapy in patients on anticoagulants.

Despite studies in the early literature showing that ECT may lead to CNS bleeding, it is unclear whether unmodified ECT increases the risk for hemorrhage in patients taking anticoagulants. The authors report two cases of depressed patients who required ECT while on coumarin derivatives. Both patients were switched to heparin. Heparin's short duration of action allowed temporary discontinuation 6-8 hours prior to each ECT with return of coagulation function close to normal when the stimulus was administered. No complications were observed in any of the patients. The authors believe that this technique minimizes any possible risks from ECT in patients on anticoagulants.

Anticoagulants↗
PubMed1976

Synthesis and screening of some substituted 3.5-dioxopyrazolidines.

Seven new 3.5-dioxopyrazolidine derivatives, incorporating in their molecule a p-substituted benzoyl grouping, were synthesized. The preliminary screening of four selected compounds showed that 1-phenyl-2-[p-nitrobenzoyl]-4.4-diethyl-3.5-dioxopyrazolidine possesses a low order of antiinflammatory activity.

Animals↗
PubMed1975

Inhibition of prolactin secretion by ergot alkaloids.

The effect of various ergot alkaloids on prolactin (Pr) secretion in adult female rats was determined by radioimmunoassay. Ergocorine (ECO) and ergocristine (ECR) in doses of 0.25 to 1.0 mg lowered serum Pr markedly by 1 h with the effect persisting for 24 h at the larger doses. Several other ergots had similar effects while the dihydro derivatives had diverse responses. The pro-oestrous surge of Pr could be blocked by ECR or ECO without interfering with the oestrous cycle. ECO or ECR could suppress the rise in serum Pr induced by oestradiol benzoate (OeB) (5-50 mug) in oophorectomized rats. Perphenazine (PE) stimulation of Pr could be partially antagonized by ECO depending on dose and timing of injections. ECO 2 mg produced an abrupt cessation of lactation with concomitant fall in serum Pr, and ovine prolactin restored this function. Evaluation of pituitary Pr concentration in lactating and intact rats receiving ECO leads to the conclusion that release of Pr from the pituitary is affected. ECO 1 or 2 mg produced a regression of dimethyl-benz(a)anthracene (DMBA) induced rat mammary tumours which could not be reversed by OeB 5 mug, with persisting low serum Pr. PE 1 mg was able to raise serum Pr and stimulated tumour growth. Several of the ergot alkaloids have a profound inhibiting effect on Pr secretion and may be used for studies on Pr action, as well as in medical therapeutics.

Animals↗