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Biomedical subjects

R H Singh

Publications and source records attributed to R H Singh.

At least 19 recordsLinked to original sources

Exercise training: significance of regional alterations in serotonin metabolism of rat brain in relation to antidepressant effect of exercise.

Alterations of 5HT and its chief metabolite 5HIAA were studied in four regions of the rat brain following acute 1-h swim exercise and 4 week chronic swim exercise (30 min/day, 6 days per week). Acute exercise significantly increased the synthesis and metabolism of 5HT in brain stem. Hypothalamus also showed increased levels of 5HT. However, no changes were observed in the cerebral cortex and hippocampus. Chronic exercise activated not only the synthesis but also the metabolism of 5HT in the cerebral cortex; this neuronal adaptation was sustained even 1 week after the termination of training. In brain stem, increased 5HT turnover was observed immediately after training. In hypothalamus, decrease in 5HT and 5HIAA levels occurred immediately after training, followed by a rebound increase in their levels after 1 week posttraining rest. In hippocampus, a delayed effect was observed, because 5HT level was unaltered immediately after the training, but its turnover decreased after 1 week rest. These findings have been discussed in an attempt to explain the antidepressant effect of exercise based on the 5HT deficiency theory of endogenous depression.

Animals

Modification of apomorphine-induced behaviour following chronic swim exercise in rats.

Four week swim exercise schedule (45 min day-1, 6 days each week) in rats led to a significant adaptive change in functional responsiveness of dopamine receptors (auto-receptors) in the nigrostriatal and mesolimbic system that was evident from the modification of behavioural responses elicited by a low dose of apomorphine, a direct acting dopamine receptor agonist. Thus, a remarkable increase in yawning response, development of full blown stereotypy, as well as profound attenuation of locomotory and hypothermic response was observed in exercise-trained rats as compared with the non-exercise group (control), following intraperitoneal administration of 0.3 mg kg-1 of apomorphine.

Analysis of Variance

An experimental evaluation of possible teratogenic potential in Boerhaavia diffusa in Albino rats.

The present study was undertaken to evaluate any possibility of teratogenic effects in Boerhaavia diffusa (Punarnava), a widely used herbal medicine for renal and urinary tract diseases by Ayurvedic physicians in India. The ethanolic extract of Boerhaavia diffusa (BDE) was administered daily in a dose of 250 mg/kg, body weight p.o., to pregnant albino female rats during the entire period of gestation. BDE was found to be devoid of any teratogenic effect as litter size and survival rate of foetuses were the same as for the normal control group and no foetal anomaly could be detected.

Animals

A randomized, controlled trial of treatment of alcoholic hepatitis with parenteral nutrition and oxandrolone. II. Short-term effects on nitrogen metabolism, metabolic balance, and nutrition.

Patients with moderately severe or severe alcoholic hepatitis, described in a companion paper in this issue, had serial studies of energy and protein metabolism and elemental balances before and during treatment for 21 days with one of four randomly assigned regimens: 1) standard therapy, consisting of abstinence, a balanced, nutritionally adequate diet, and multivitamins; 2) oxandrolone (20 mg orally four times a day) plus standard therapy; 3) nutritional supplementation, consisting of 2 liters of 3.5% crystalline amino acids in 5% dextrose given by peripheral vein (PPN) plus standard therapy; and 4) a combination of the other three treatments. Dietary and intravenous intakes and weights were recorded daily, and weekly averages were calculated. Anthropometric measurements and blood studies were done weekly; blood studies included white blood cell counts and differentials, serum prealbumin, transferrin, and total protein and plasma aminograms. Four-days complete balance studies and measures of 15N,1-13C-leucine metabolism also were performed at baseline and after the treatment period. Major findings were as follows: a) Intakes of total calories and protein were significantly higher in PPN-treated than in other groups. b) All patients had positive elemental balances, both at baseline and at the end of the treatment period. However, those treated with PPN (with or without oxandrolone) had higher positive balances of nitrogen, potassium, phosphorus, and magnesium, indicating improvement in lean body mass. c) Anthropometric measurements showed no significant changes, but measures of the visceral protein compartment (serum prealbumin, transferrin, total protein, total lymphocyte count) improved significantly with time. For most of these variables, increases were significantly greater in those treated with PPN with or without oxandrolone than in the other groups. However, for prealbumin, the increase was greatest in the oxandrolone-treated group d) PPN treatment produced dramatic increases in levels of branched-chain amino acids and improvement in the ratio of plasma branched chain to aromatic amino acids. Other treatments had no effect on plasma aminograms. e) Metabolism of 15N,1-13C-leucine was normal and was not affected significantly by treatment. Therapy with PPN and/or oxandrolone was tolerated well. We conclude that PPN has favorable effects on energy and protein metabolism in florid alcoholic hepatitis; oxandrolone has lesser effects, although it may exert some additional action and particularly increases serum prealbumin levels. The results support the use of nutritional supplementation in therapy of moderately severe or severe alcoholic hepatitis.

Adult

Catecholamines in diabetic retinopathy.

An attempt has been made to correlate the catecholamines and diabetic retinopathy. Plasma catecholamines and their urinary metabolite, vanillylmandelic acid, were measured in 53 cases of different stages of diabetic retinopathy and the results compared with the 30 cases of the control group. The study revealed a rise in total plasma catecholamines that was significant in the preretinopathic stage and highly significant in the early as well as in the late stages of diabetic retinopathy. Thus, catecholamines may play an important role in the pathogenesis of diabetic retinopathy by stimulating the counterregulatory hormones, namely growth hormone and glucagon.

Catecholamines

Cortisol in diabetic retinopathy.

Plasma cortisol levels and its metabolite-17-hydroxycorticosteroids from the urine of 53 patients were evaluated. These 53 patients had early and late stages of diabetic retinopathy. Values were compared with 30 cases of a control group. Plasma cortisol was found to be raised significantly in early as well as in advanced stages of retinopathy, while 17-hydroxycorticosteroid was significantly raised in earlier stages of diabetic retinopathy only. The findings suggest that increased plasma cortisol levels may take some part in the production of diabetic retinopathy.

17-Hydroxycorticosteroids