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Biomedical subjects

S A Taha

Publications and source records attributed to S A Taha.

At least 19 recordsLinked to original sources
PubMed2005

Nucleus accumbens dopamine release is necessary and sufficient to promote the behavioral response to reward-predictive cues.

The nucleus accumbens is part of the neural circuit that controls reward-seeking in response to reward-predictive cues. Dopamine release in the accumbens is essential for the normal functioning of this circuit. Previous studies have shown that injection of dopamine receptor antagonists into the accumbens severely impairs an animal's ability to perform operant behaviors specified by predictive cues. Furthermore, excitations and inhibitions of accumbens neurons evoked by such cues are abolished by inactivation of the ventral tegmental area, the major dopaminergic input to the accumbens. These results indicate that dopamine is necessary to elicit neural activity in the accumbens that drives the behavioral response to cues. Here we show that accumbens dopamine release is causal to the rats' reward-seeking behavioral response by demonstrating that dopamine in this structure is both necessary and sufficient to promote the appropriate behavioral response to reward-predictive cues.

Animals↗
PubMed2004

Urethral calculi: presentation and management.

OBJECTIVE: To determine the occurrence, symptoms, treatment and outcome in patients with urethral stones. PATIENTS AND METHODS: Fifty-one consecutive patients with urethral calculi were assessed prospectively; all were male and one was an infant. RESULTS: Acute retention of urine occurred in 78% of patients, urethral anatomical pathology in 6% and posterior urethral calculi in 88%. The urethral stones, solitary in each patient, consisted of calcium oxalate in 86%, struvite in 6%, mixed stones in 4%, calcium phosphate in 2% and uric acid in 2%. A methodical approach to therapy was used which aimed to clearly define the circumstances in which a given procedure was used, and the resulting success rate. CONCLUSION: The common belief that most urethral calculi in patients in developing countries originate from the bladder does not seem to be generally applicable. Urethral anatomical pathology does not seem to be a necessary condition for most of these calculi.

Adolescent↗
PubMed2000

Anterior hypospadias. Is repair necessary with urination in a sitting or squatting position?

OBJECTIVE: To determine the chronic complication rate of anterior hypospadias repair and to explore whether the practice of placing the neomeatus at the tip of the penis should be applicable to all cases in our community where urination is in a sitting/squatting position. METHODS: Over a 10-year period commencing 1st September 1987, 312 patients had hypospadias repair of whom 72% had anterior hypospadias. The meatus was advanced to the tip of the penis in all repairs. The location of the meatus was also determined in 281 non-complaining men with a straight penis and normal sexual and reproductive functions. Following prior information that anterior hypospadias was not associated with sexual and reproductive dysfunction, 51 patients were given a choice between repair or no repair. RESULTS: Urethrocutaneous fistula occurred in 5% of patients, urethral stricture in 3% and meatal retraction in 3%, with 92% of patients having no complications. Forty six percent of non-complaining men had the meatus in locations other than the tip of the penis. Of 51 patients with the benefit of informed consent, 73% opted for no repair. CONCLUSION: Our results of anterior hypospadias repair compare favourably with those of other centers. Placement of the meatus at the tip of the penis for anterior hypospadias should not be applicable to all patients in this community where urination is in a sitting/squatting position. Before such repairs, an informed consent is warranted by making the patients and their parents aware of the non-association of sexual and reproductive disorders with these anomalies.

Adolescent↗
PubMed1998

Effect of ambrein on smooth muscle responses to various agonists.

The pharmacological effects of ambrein (isolated from ambergris) on the contractile responses induced by some agonists in smooth muscle preparations were investigated. Ambrein in the concentration range of 10, 50 and 250 microg/ml decreased the spontaneous contraction of the isolated rabbit jejunum, rat uterus and guinea-pig vas deferens. Ambrein-induced antagonism to acetylcholine (Ach) in the guinea-pig ileum was abolished when the concentration of calcium chloride in the Tyrode's solution was increased to 5 mM/l. Furthermore, ambrein did not antagonise nicotine-induced contractions in the isolated rabbit jejunum or serotonin-induced contractions in the isolated guinea-pig ileum and vas deferens or the rat uterus. However, ambrein in the concentration range of 10, 50 and 250 microg/ml antagonised prostaglandins (PGs) E2, D2, F2alpha, and oxytocin-induced contractions in the rat uterus in vitro. Ambrein also antagonised (+/-) noradrenaline and (-) adrenaline-induced contractions in the isolated guinea-pig vas deferens. It is concluded that ambrein-induced non-selective dose-dependent antagonism to the effects of some agonists (Ach, adrenaline, noradrenaline, PGs and oxytocin) in some smooth muscles may be due to the ability of this compound to interfere with the mobilisation of extracellular Ca2+ required for muscular contractions induced by these agonists.

Animals↗
PubMed1996

Hypoglycemic effect and protein nutritive quality of soy and methionine-supplemented whole durum pasta products.

New low cost, high-protein and high-fiber pasta products processed from whole durum meal (WD) solely, WD supplemented with 7% or 12% defatted soy flour (SF), or 12% SF plus 0.3% methionine were evaluated in comparison with the regular pasta made of pure durum semolina (DS). Their protein nutritive quality was biologically evaluated by rat growth studies using diets containing 9% protein, through the parameters: food efficiency ratio (FER), protein efficiency ratio (PER), net protein utilization (NPU), digestibility coefficient (DC) and biological value (BV). The original products were administered to diabetic hypercholesterolemic albino rats, (injected with alloxane) to study their effects on the levels of blood glucose and plasma lipid fractions. The results indicate that diets based on pasta made of WD supplemented with SE or SF plus methionine had superior protein quality and succeeded in supporting normal growth of rats in contrast to the diets based on pasta made of unsupplemented WD or DS. These assays demonstrated that the values of FER, PER, NPU and BV of WD-pasta increased with increasing SF supplementation. However, high-fiber pasta made of unrefined WD solely or with SF had lower DC values compared to that of the regular DS-pasta. DC values decreased as the added SF increased. Adding methionine evidently affected FER, PER, BV and NPU values. Administration of high-protein and high-fiber pasta samples made of WD solely, supplemented with SF or SF plus methionine significantly reduced the elevated blood glucose as well as plasma cholesterol and plasma lipid fractions in hypercholesterolemic diabetic rats. Overall, considering nutritional evaluation, protein cost as well as hypoglycemic and hypocholesterolemic effects the pasta composed of 12% SF-WD and supplemented with 0.3% methionine represented the best high-fiber; high-protein and high-quality product.

Animals↗
PubMed1996

Protection by epicoprostanol against hyperglycemia and insulitis in normal and diabetic rats.

Epicoprostanol (3-alpha-hydroxy-5 beta-cholestanol) has been studied for its effects on blood glucose and plasma insulin levels in rodents. Epicoprostanol significantly induced hypoglycemia and increased insulin levels in rat blood plasma by 88% and 66% compared to that of control after 2 h and 4 h of acute treatment at 100 mg/kg dose. It also highly significantly lowered blood glucose levels in a dose dependent manner at 50, 100 and 200 mg/kg doses when administered to alloxan-rendered moderately diabetic rats after 120 and 240 min of treatment. Similarly, epicoprostanol, with the same dosage regimen, caused hypoglycemia in streptozotocin-induced severe diabetic rats, to a similar extent at the same time-points. However, the lowest dose (10 mg/kg) failed to produce a striking effect in either of the diabetic groups. In normoglycemic rats, plasma insulin levels were affected significantly after a single dose (100 mg/kg) of epicoprostanol. In contrast, diabetic animals suffering from insulitis showed a significant decline in hyperglycemia, strongly suggesting an insulin-like action of epicoprostanol. It seems likely that epicoprostanol acts through a mechanism other than hyperinsulinemia.

Animals↗
PubMed1995

Effect of (-)-cathinone, a psychoactive alkaloid from khat (Catha edulis Forsk.) and caffeine on sexual behaviour in rats.

The effect of (-)-cathinone, caffeine and their combinations was studied on the sexual behaviour of male rats. Male sexual activities were assessed by recording the erectile responses (grooming of genitalis, yawning/stretching and homosexual mounting), in the absence of females. The copulatory behaviour was observed by caging males with receptive females brought into oestrus with s.c. injection of oestradiol benzoate and progesterone. The copulatory pattern of male rats (mounting, intromissions, ejaculations and refractory period) was recorded. The oral treatment of cathinone (5 mg kg-1 day-1), caffeine (50 mg kg-1 day-1) and their combinations for 15 days increased arousal (motivation) in male rats as evidenced by increased mounting performance and anogenital investigatory behaviour. However, erectile and ejaculatory responses, measured in the present study, showed no stimulant effect. It is conceivable from the present results that cathinone, the psychostimulant constituent of khat modified masculine pattern behaviour and caffeine also changed the effect of cathinone when administered concomitantly. However, our data provide no evidence that cathinone could be considered as an aphrodisiac.

Administration, Oral↗
PubMed1995

A study of ambrein treatment for the evaluation of change in plasma biochemical parameters in rats.

Biochemical effects of acute and subacute treatments with ambrein were investigated in rats by measuring the total proteins, cholesterol, triglycerides, GOT, GPT and alkaline phosphatase in the blood plasma. Also, determinations of prothrombin time (PT), partial thrombin time (PTT), thrombin time (TT) and fibrinogen level were performed. Furthermore, changes in plasma electrolyte concentration were studied. Ambrein administered i.p. did not cause any toxic symptoms in the liver as revealed by the histology of the liver tissue both in acute and subacute treatments. Ambrein itself did not significantly affect the plasma protein, cholesterol, GOT and GPT profiles, but lowered alkaline phosphatase at high doses (50 and 250 mg/kg) after subacute treatment. Thus far, no specific pattern of action of ambrein in electrolyte control has been found. However, it increased PT, PTT and TT and decreased fibrinogen levels in both the acute and subacute studies, pointing towards its potential as an anticoagulant and antifibrinogenic agent.

Alanine Transaminase↗
PubMed1994

Male pseudohermaphroditism: factors determining the gender of rearing in Saudi Arabia.

OBJECTIVE: Experience with male pseudohermaphrodites at King Fahd Hospital of King Faisal University, Al-Khobar, Saudi Arabia from 1981 to 1991 was reviewed to ascertain the factors determining the gender of rearing. METHODS: The records of 14 patients consisting of 6 prepubertal and 8 postpubertal patients were studied. None of the patients had any prior evaluation or treatment, since their gender assignment at birth was carried out by midwives in rural communities. The males presented to our hospital with ambiguous genitalia: small phallus, bifid scrotum, perineoscrotal hypospadias, and undescended testes (UDT). Most of those raised as females presented in the postpubertal period seeking remedy for deep voice, excessive musculature, facial hair, erection of the phallus, ejaculation, inappropriate attraction to the female sex, and primary amenorrhea. As their male genotype became determined, all the patients and/or their parents, with the exception of one, insisted on appropriate reconstructive surgery to the male gender. This report focuses primarily on 11 patients assigned a female gender at birth, 10 of whom insisted on a gender change. RESULTS: Most adolescents and adults still complained of small penises after reconstructive surgery, but cherished their male role. CONCLUSIONS: The male genotype is a more important factor than phallic adequacy in determining the gender of rearing in the Kingdom of Saudi Arabia, an observation attributable to the financial, social, and cultural benefits that the male gender confers in Saudi society.

Adolescent↗
PubMed1994

Laboratory induced resistance to praziquantel in experimental schistosomiasis.

To study the effect of praziquantel (PZQ) on successive generations of S. mansoni worms, infected mice were treated 6 weeks after infection with different doses of PZQ (300, 500 mg/kg.), the schistosome strain was originally obtained from an infected Egyptian patient. The eggs subsequently produced by worms that had survived the PZQ treatment were used to infect snails and mice of the following generations. The results were expressed as average number of worms and cure rates in comparison with control groups. It was found that the use of PZQ., especially in low subcurative dose may lead to the development of resistance to therapeutic dose of the drug in following generations.

Animals↗
PubMed1993

Experimental schistomiasis: the effect of chemotherapy on concomitant immunity and resistance to reinfection.

To study the effect of chemotherapy on concomitant immunity, mice infected with Schistosoma mansoni were treated after either 8 or 16 weeks of primary infection and challnged at different periods after treatment. Results were compared with infected un-treated groups of mice. It was found that in mice treated 8 weeks after infection the degree of protection decreased gradually with time and 16 weeks after treatment no significant degree of protection was obtained. On the other hand, mice infected for 16 weeks prior to treatment showed higher degrees of protection and there was still significant degree of resistance to challenge infection after 16 weeks of treatment. It was concluded that in schistosomiasis mansoni there is a certain degree of resistance to reinfection after successful treatment of primary infection prior to treatment.

Animals↗
PubMed1992

Studies on the mode of action of ambrein as a new antinociceptive compound.

The compound ambrein was isolated from ambergris, which is commonly used as an analgesic in the Saudi folklore medicine. The LD50 of ambrein, given intraperitoneally (i.p.) in mice, was found to be high (7.5 g/kg), and ambrein proved to be a safe compound in this species. In the hotplate test, ambrein was found to possess antinociceptive activity in mice at doses which did not sedate or incapacitate the animals. By the i.p. administration route, ambrein produced antinociception in mice at a dose as low as 10 mg/kg. The antinociceptive activity of ambrein (250 mg/kg i.p.) was inhibited by a noradrenergic neurotoxin (DSP-4) and by naloxone, methysergide or prazosin. It was not influenced by a serotonin depletor, p-chlorophenylalanine. The possible mechanism of ambrein antinociception is discussed.

Analgesics↗
PubMed1991

Effect of ambrein on blood glucose levels of rats.

Ambrein reduced the blood glucose level of normal and moderately alloxan-diabetic rats but did not reduce the blood glucose levels of severely-diabetic rats. Ambrein did not reduce the hyperglycemia of glucose-loaded rats also given mannoheptulose but it reduced the hyperglycemia of glucose-loaded rats in the absence of mannoheptulose. Results suggested that the hypoglycemic activity of ambrein may be mediated by enhanced glucose utilization.

Administration, Oral↗
PubMed1989

Chemical investigation of the internal secretion of the sperm blue whale.

Ambergris, which is an internal secretion of the sperm blue whale, was extracted with 96% ethanol. The saponified and unsapondied portions have been studied in detail. The number of fractions and components of the unsaponified matter as separated by column and thin layer Chromatography confirm the presence of ambrein (triterpenoid) as well as same other steroid. The saponified portion is reported to contain stearic, oleic, linoleic, archidic and betenic acids. More than one compound have been found in each fraction.

Journal Article↗
PubMed1988

Prognosis of radiologically non-functioning obstructed kidneys.

Twenty patients found to have unilateral radiologically non-functioning obstructed kidneys on excretory urography (IVU), and who had normal contralateral kidneys, were further evaluated. Ultrasonography, radionuclide imaging and CT scan were carried out pre-operatively to try to predict which of the kidneys were potentially recoverable after relief of obstruction. Percutaneous nephrostomy was also performed on the last consecutive 7 patients 4 weeks before definitive treatment and the function of the kidneys determined daily. The patients were re-evaluated 2 months after the relief of obstruction. Ultrasonography, radionuclide imaging and CT scan were not found to be reliable in predicting whether these kidneys were potentially recoverable. We consider percutaneous nephrostomy a good procedure for obtaining prognostic information prior to definitive surgery.

Adult↗
PubMed1988

Psychological aspects of intersex in Saudi patients.

Four cases of male pseudo-hermaphrodism were seen post pubertal. All had been reared as females unambiguously since birth. Two cases developed male gender identity post pubertal, but failed to declare themselves to their families and society until a similar case had been publicized in the local newspaper. The third case did not reveal her problem to her family even after being informed by a doctor at the age of 15, and was discovered accidentally at the age of 22 on routine medical examination. The fourth was discovered accidentally at age 40 after having been married and divorced. The families of the four cases shared a strong desire for their children to be reassigned to the male sex including the third case, irrespective of being assured of her female gender identity by physicians. Psychiatric and social problems encountered pre- and post-operatively are discussed with particular emphasis on the role of culture and traditions.

Adaptation, Psychological↗
PubMed1987

Homozygous sickle cell disease and priapism in the eastern province of Saudi Arabia.

Two adult sickle cell homozygotes from the eastern oases of the Kingdom of Saudi Arabia presented with severe persistent priapism. Each patient had a high Hb F of 24%, and their red cells were neither hypochromic nor microcytic. Priapism probably occurs more frequently in homozygous sickle cell disease than reported previously from this region. It would appear that a high fetal haemoglobin alone without hypochromia and microcytosis--features suggestive of co-existing alpha-thalassaemia--does not protect against this agonizing vaso-occlusive event.

Adult↗