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Biomedical subjects

B B Gupta

Publications and source records attributed to B B Gupta.

At least 37 records · Page 2Linked to original sources
PubMed1987

Effect of melatonin on gonads, body weight, and luteinizing hormone (LH) dependent coloration of the Indian finch, Lal munia (Estrilda amandava).

Four doses of melatonin were administered intramuscularly over 30 days in separate groups of intact adult male Lal munia, Estrilda amandava, during mid-day (1300 hr) and mid-night (0100 hr) in separate sets during the month of August (late progressive phase), and their effects were studied on the body weight, gonadal and thyroidal activities, and luteinizing hormone (LH)-dependent plumage and beak pigmentation. Melatonin, irrespective of its dose and the time of administration, invariably induced complete inhibition of seasonal gonadal growth and activity, and also the LH-dependent plumage pigmentation. Melatonin had no effect on LH-dependent beak coloration. The inhibitory effect of melatonin on the body weight growth was found to be dependent on the time of administration and the dose of the hormone. Melatonin inhibited the thyroid activity in all the groups. These findings seem to suggest that while melatonin influences gonadal activity, body weight growth, and thyroid activity by acting directly at the hypothalamo-hypophyseal complex, it counteracts the effect of LH at the feather papillae level. Further, synthesis and/or release of FSH seems to be more sensitive to melatonin than that of LH. However, the metabolic action of melatonin might be species specific.

Animals↗
PubMed1986

Membrane plasma separation through small-area, hollow-fiber filters.

The filtration capabilities of small polypropylene hollow-fiber plasma filters with membrane areas ranging from 100 to 1,000 cm2 have been investigated. It is found that the filtration flux per unit membrane area is approximately proportional to the wall shear rate gamma w at least up to gamma w = 7,500 s-1. As a result, the total filtration flow rate increases very little when the number of fibers is increased as the increase in membrane area is offset by the decrease in shear rate, but it increases with the fiber length L as L 2/3. Hemolysis occurs when the transmembrane pressure exceeds a certain threshold, but this threshold is itself an increasing function of shear rate. As a result, it is possible to circulate high blood flow rates even in very small filters (100 cm2) without hemolysis, provided the fiber length is below a critical value.

Animals↗
PubMed1985

Role of thyroid and testicular hormones in the oxidative metabolism of the Indian garden lizard, Calotes versicolor.

L-Thyroxine (L-T4) and testosterone were administered separately to intact, thyroidectomized, and castrated male Indian garden lizards, Calotes versicolor (maintained under natural climatic conditions) throughout the year to study their effects on the whole-body oxygen consumption and on tissue (liver, muscle, kidney, and brain) respiration. The findings indicate that the calorigenic actions of L-T4 and testosterone are independent of ambient temperature, and different tissues have different, temperature-independent, annual rhythms of sensitivity to L-T4 and testosterone. Internal factors seem to play a major role in the determination of these annual tissue sensitivity rhythms. Effects of thyroidectomy and castration are brought about by decreased levels of both thyroidal and testicular hormones. It is suggested that gonadal hormones are directly involved in the oxidative metabolism of Calotes which is regulated jointly by thyroid and gonadal steroids, and the degree of involvement of the glands depends upon the energy demand and sensitivity of tissues during different months of the year.

Animals↗
PubMed1984

Role of thyroid and testicular hormones in the regulation of basal metabolic rate, gonad development, and body weight of spotted munia, Lonchura punctulata.

Normal saline, L-thyroxine (L-T4, 0.5 micrograms/bird/day), and testosterone (100 micrograms/bird/day) were administered separately to intact, thyroidectomized, and castrated spotted munia over a 30-day period and the effects on basal metabolic rate (BMR), gonads, and body weight were recorded. Thyroidectomy and castration decreased the BMR. L-Thyroxine increased the BMR of intact and thyroidectomized but not of the castrated birds. Testosterone had no effect on BMR of either the intact or of the operated birds. L-Thyroxine and testosterone both had no effect on regressing gonads but inhibited thyroidectomy-induced testicular development. Body weight increased in intact, testosterone-treated birds, and in thyroidectomized and castrated spotted munia. L-Thyroxine inhibited body weight gain only in thyroidectomized birds. It is suggested that the physiological actions of L-T4 and testosterone depend on the gonadal status, thyroid activity, and nature of the thyroid-gonad relationship.

Animals↗
PubMed1984

Thyroid and annual gonad development, body weight, plumage pigmentation, and bill color cycles of lal munia, Estrilda amandava.

Long-term administration of L-thyroxine (T4) in the wax bill (lal munia) inhibited the current gonad development cycle, and the increase in gonadal volume in the second cycle was suppressed only by higher concentrations. Gonadal inhibition by high but not by low doses of L-T4 was associated with a failure in the development of LH-dependent pigmented nuptial plumage. This suggests that L-T4 depresses FSH secretion more readily than LH secretion. The results indicate that the effects of L-T4 administration on the body weight cycle depends upon the physiological and/or gonadal status of the bird at the start of the experiment and that the juvenile hypothalamo-hypophysial-gonadal axis is more sensitive to L-T4 than that of the adult birds. The bill color, like plumage pigmentation, appears to be LH controlled. It is suggested that while thyroid hormone, acting by way of the hypothalamo-hypophysial complex and/or by direct action on the feather papillae, modulates the annual cycles of plumage pigmentation, bill color, gonad development, and body weight of lal munia, the finch has an endogenous mechanism which enables it to adapt to chronic hyperthyroidism in such a way that breeding occurs at the normal time of the year.

Animals↗
PubMed1984

In vitro study of combined convection- diffusion mass transfer in hemodialysers.

Clearance measurements have been obtained for urea, Vit B12 and myoglobin by simultaneous hemodialysis and ultrafiltration (UF) techniques, using various commercially available hemodialysers. The experimental results confirm that the overall clearance is less than the clearance of each process occurring separately due to interaction between convection and diffusion. Adequate urea clearance (100 ml/min) can be obtained either by using high ultrafiltration (60 ml/min) with low dialysate flow rate (70 ml/min) or moderate ultrafiltration (less than 30 ml/min) with higher dialysate flow rate (120 ml/min). The comparison of experimental clearance with the predictions of theoretical model (1) for urea are found to be in good agreement for dialysate flow rates of more than 300 ml/min and for smaller dialysate flow rates the predicted clearances are higher than measured ones. An approximate correlation for the overall clearance is CL = CLD + QF/2 where CLD is the dialytic clearance and QF the UF flow rate.

Blood↗
PubMed1983

Determination of native and denatured milk proteins by high-performance size exclusion chromatography.

High-performance size exclusion chromatography on a TSK 3000 SW column was used to separate and quantify the individual milk proteins in their native and/or denatured state. Quantitation of the individual native whey proteins within +/- 10% was achieved. The denatured proteins were dissociated into their monomer units by using sodium dodecyl sulphate and beta-mercaptoethanol. A good separation of the whey protein monomers was achieved and the quantitation of the individual whey proteins within +/- 10% was possible. Under these conditions, alpha s1- and beta-casein were eluted as one peak, whereas kappa-casein and gamma-casein were eluted in the same position as beta-lactoglobulin and alpha-lactalbumin respectively. A method for calculating the areas and hence the concentration of the individual proteins in a mixture of casein and whey proteins is described.

Animals↗
PubMed1983

Thyroid and gonad in the oxidative metabolism, erythropoiesis, and light response of the migratory redheaded bunting, Emberiza bruniceps.

In the thyroidectomized, adult male redheaded bunting exposed to a L/D cycle of 15/09, there were no significant changes in body weight, gonad size, respiratory rates of whole body, liver, muscle, red blood cell number, hemoglobin concentration, or hematocrit, unlike in intact birds. Further, while testosterone appeared as effective as L-T4 in determining body weight, gonadal size, and activity and oxygen uptake by skeletal muscle, it was of greater significance for kidney respiration and of secondary importance in its influence on blood morphology and respiratory rates of the liver and of the whole body of the bird.

Animals↗
PubMed1983

Role of thyroid in tissue respiration of birds.

Thyroidectomy after 1 week, 1 month, and 13 months significantly depressed and low level of L-T4 significantly elevated the oxygen uptake of the liver and skeletal muscle of spotted munia and common myna. A higher dose of L-T4 had no effect on the rate of respiration. A reexamination of the published results on submammalian vertebrates together with those presented here suggests that an uniform pattern of response of skeletal muscle emerges if the values from thyroidectomized animals are compared not only with the final controls but also with the initial controls. It is, therefore, suggested that all the earlier works be reexamined and reinterpreted.

Animals↗
PubMed1983

Adrenal hormones and oxidative metabolism of the garden lizard (Calotes versicolor).

Daily administration of adrenaline over a 10-day period invariably induced significant increases in the metabolic rate of the whole body and of specific tissue (liver, muscle, kidney and brain) of both intact and thyroidectomized lizards except during June (breeding season) when the presence of thyroid hormones was a prerequisite for the stimulation of oxygen consumption by the whole body, muscle, kidney and brain but not by the liver. Corticosterone had no effect on whole body oxygen consumption but stimulated, inhibited or was without influence on the oxygen consumption of individual tissues, depending on the season and the presence or absence of thyroid hormones. It is suggested that adrenaline, due to its temperature-independent calorigenic effect, acts as the emergency hormone for energy release and helps the animal to survive during hibernation (winter months) when almost all the endocrine glands are inactive.

Animals↗