Biomedical subjects
Publications and source records attributed to B Singh.
When temporary or palliative urinary diversion is necessary the Gibbons ureteral stent has reduced markedly the need for nephrostomy. Of 48 patients 41 (85 per cent) had successful insertion of stents. Only 1 of these patients had to undergo nephrostomy at a later date. Complications have been minimal and the patients' tolerance has been excellent.
Extramedullary plasmacytomas of the head and neck are very uncommon tumours. Three rare cases of extramedullary plasmacytoma are presented-one each in the nose, larynx and maxilla.
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Administration of vasodilator, sodium nitrite (20 mg/kg body weight), 30 min before alpha-chlorohydrin treatment (90 mg/kg body weight) prevented the chlorohydrin-induced lesion in rat testis--epididymis complex. However, administration of vasodilator 90 min after alpha-chlorohydrin treatment did not prevent the chlorohydrin-induced lesion in the testis--epididymis complex. These observations suggest that the testicular vasculature is involved in drug action.
Evoked responses (ER) to stimulation of spermatic nerve were picked up in conscious monkeys from hypothalamic limbic and cerebral cortical regions. The effect of intravenous injection of testosterone propionate (TPss; 0.4 mg/kg) on ER was examined in the same animal. Hormone administration caused inhibition or potentiation of ER in different regions of brain. The duration of hormone effect also suggested area specificity. A significant, immediate reduction in ER amplitude was produced by hormone injection in the ventromedial nucleus. On the contrary an increase of ER was observed in the anterior hypothalamus and in several limbic areas. Genital sensory motor cortex showed slight potentiation. The results support the hypothesis proposed in earlier EEG studies that TP and genital afferent input probably play a selective role in brain mechanisms underlying organized and integrated expression of reproductive functions.
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Isatin has been found to inhibit rat kidney alkaline phosphatase (EC 3.1.3.1). The inhibition is dependent on isatin concentration and is of un-competitive type. The hydrolysis of disodium phenyl phosphate by the enzyme at different temperatures (17--37 degrees C) obeys the Arrhenius equation. Energy of activation in the absence and presence of isatin has been found to be 9.84 and 10.24 kCal/mol. The hyperbolic profile of isatin inhibition; the lowering of both Km and Vmax in the presence of isatin, and, small changes in enthalpy, free energy and entropy in the presence of isatin suggest a non-allosteric un-competitive inhibition of the enzyme.
In previous work we have found that partially purified 125I-labeled anti H-2 antibody is localized in the placenta when injected i.v. into females pregnant by males bearing the target haplotype. This led to the concept that the placenta is an H-2 antigen-bearing immunoabsorbent barrier between mother and fetus. In this report we have used an anti-H-2Kk monoclonal antibody of the IgG2a subclass, also labeled with 125I, to verify this concept, as well as to improve the genetic definition of the immunoabsorbent antigen. In addition we have prepared F(ab')2 fragments of this antibody, and these also show the immunoabsorbent effect. This indicates that transport into fetally derived tissues via Fc binding is not a prerequisite for reaction of the antibody with paternal strain H-2 K antigens.
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A partially purified 125I-labeled antibody directed against the murine major histocompatibility complex and injected i.v. pregnant females is selectively absorbed by the placenta when the fetus bears the appropriate targen antigen. The placenta specifically absorbs the antibody at both 13 days and 17 days of gestation, and the differential uptake is found as early as 2 hr after injection and as late as 12 hr. It is also seen in 13-day placentas that have had the fetus removed surgically, indicating that fetal circulation is not essential for the absorption to take place. Specificity controls eliminate the possibility that the differential uptake is due to Fc receptor binding or undefined effects of hybrid vigor. This increase in binding is not seen in the livers, spleens, kidneys, or lungs of the pregnant females. There is a slight decrease in radioactivity in the serum. These results indicate that the placenta is a paternal antigen-bearing immunoabsorbent that could serve as a barrier between the maternal immune response and the semi-allogeneic fetus.
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Electrical stimulation of hypothalamic areas through stereotaxically implanted electrodes were carried out in conscious male rhesus monkeys. There was a significant increase in immunoreactive insulin (IRI) following laterla hypothalamus (LHA) stimulation. An opposite response was obtained from ventromedial hypothalamus (VMH). Thus, insulinogenic and insulinoprival responses were obtained from feeding and satiety, suggesting a significant role of insulin in the regulation of food intake.
Isatin has been found to inhibit rat testicular alkaline phosphatase (EC 3.1.3.1). That the inhibition is non-competitive as well as non-allosteric is evident from a) the hyperbolic curve relating inhibition as a function of inhibitor concentration; b) the small change in enthalpy, free energy and entropy; c) the number of isatin molecules associating with 1 molecule of the enzyme (n=1.29); and, d) the decrease in the values of both Km and Vmax in the presence of isatin.
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Three cases of strangulation of the glans penis by hair are reported. Ensuing complications such as urethrocutaneous fistula and gangrene of the glans are described. The need for prompt diagnosis and treatment is stressed.
alpha-Chlorohydrin, 6.5 mg/kg body weight for 14 days, did not alter total phospholipids, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl serine, phosphatidyl inositol and sphingomyelin in rat testis and caput and corpus epididymis. However, marked decrease in total phospholipids, phosphatidyl choline, phosphatidyl ethanolamine and phosphatidyl inositol in cauda epididymis and vas deferens was observed. p32 incorporation also showed similar changes in phospholipids.