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Biomedical subjects

S K Sarkar

Publications and source records attributed to S K Sarkar.

At least 19 recordsLinked to original sources
PubMed1992

Hepatoprotective activity of Azadirachta indica leaves on paracetamol induced hepatic damage in rats.

Effect of A. indica leaf extract on serum enzyme levels (glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, acid phosphatase and alkaline phosphatase) elevated by paracetamol in rats was studied with a view to observe any possible hepatoprotective effect of this plant. It was interesting to observe that serum enzyme levels were much elevated in paracetamol induced animals than in those receiving a combination of paracetamol and lead extract. It is stipulated that the extract treated group was protected from hepatic cell damage caused by paracetamol induction. The findings were further confirmed by histopathological study of liver.

Acetaminophen↗
PubMed1992

Ontogenetic and comparative analysis of LDH isozymes in the three species of Indian major carp.

Expression patterns of lactate dehydrogenase (LDH) isozyme were investigated in embryonic and post embryonic stages of Labeo rohita, Cirrhinus mrigala and Catla catla using starch gel electrophoresis. Species specific and differential enzyme locus (gene) expression patterns were found in LDH up to 18th hr of study. The isozyme up to 36th hr after fertilization seemed to be completely active and showed electrophoretic patterns very similar to those of the adults. Comparative analysis of the isozyme of the three species permitted species identification even during the embryonic stages when it is impossible to identify on morphological characters only. Also, the genetic studies indicated different taxonomical and evolutionary histories of the species.

Animals↗
PubMed1991

Analysis of immunocompetent cells in the bat, Pteropus giganteus: isolation and scanning electron microscopic characterization.

Immunocompetent cells of the Indian fruit bat (P. giganteus) were characterized by differential surface adhesiveness and surface topography. We observed three cell types: (1) plastic adherent with pseudopodia; (2) nylon wool adherent with small microvilli and pits; and (3) a nylon wool nonadherent with comparatively smooth surfaces. These cell types resemble, respectively, macrophages, B cells and T cells of other mammals, including mice and humans. The disposition of microvilli on the B-type cell surface changes significantly after immunization, which suggests modulation of the molecular organization of the cell membrane and its fluidity. The proportions of these three cell types are not much different from those found in mice. Follicular dendritic cells, capable of retaining antigen for long periods in mice, have also been detected in bats. Further characterization of immunocompetent cells wil help in understanding the mechanism of immune responses in bats.

Animals↗
PubMed1991

Hypoglycemic and antihyperglycemic effect of leaves of Vinca rosea linn.

Oral administration of water fraction of alcoholic extract of leaves of Vinca rosea (fam. apocynaeceae) led to marked lowering of blood glucose level in normal and streptozotocin induced diabetic rats. The hypoglycemic effect of the fraction was comparable with that of tolbutamide.

Administration, Oral↗
PubMed1978

Circular dichroism of beta turns in peptides and proteins.

Circular dichroism (CD) spectra are reported for two groups of cyclic hexapeptides having beta turns whose geometry can be firmly established by X-ray crystallography and by NMR spectroscopy. One series contains the sequence L-Pro-D-Phe in the geometry of the classical type II beta turn, while the second group has the sequence D-Phe-L-Pro in the closely related geometry of the gramicidin S turn. CD data on the hydrogenated peptides show that in neither series do Cotton effects due to the aromatic phenylalanyl chromophore make a significant contribution to the spectra in the 195--240-nm region. In spite of the close geometric similarity of the beta turns of these two groups of peptides, their CD spectra are quite distinct. Furthermore, comparison of our data with the CD spectra of published models for beta-turn structures suggests that it may not be possible to characterize the contribution of all beta turns to the CD spectra of proteins by a single model curve. the CD spectra of model beta turns will be more useful in characterizing the folding of oligopeptides and sequence polypeptides, where a single type of turn is present.

Circular Dichroism↗
PubMed1976

Seasonal variations in the histology of the pituitary gland of Cirrhinus mrigala (Ham.) an Indian freshwater major carp, in relation to gonadal activity.

1. Seasonal variations in the histology of the pituitary gland of Cirrhinus mrigala (Ham.), an Indian freshwater major carp, in relation to gonadal activity has been studied during a one year period commencing, January, 1971. 2. The proximal pars distalis undergoes a great deal of seasonal variation in size, weight and nature of pituicytes. 3. The percentage composition of acidophils and cyanophils in the proximal pars distalis show a reciprocal relationship during the year. The acidophils predominate during the restitution phase of the gonads while the cyanophils preponderate among the different cell types during the breeding season. 4. The chromophobes do not show any significant fluctuation in numerical abundance in relation to gonadal activity. 5. Cyanophils of the proximal pars distalis undergo changes with change in gonadal activity Concentration of glycoproteinaceous material is extremely low during the restitution phase but high during the maturation phase. The cyanophils also undergo hypertrophy and hyperplasia during the spawning period. The latter discharge their contents and become vacuolated during the post spawning period. 6. The number and size of the globules in the cyanophils are related to gonadal activity. 7. Acidophils present in the rostral pars distalis and pars intermedia do not appear to be related to gonadal activity in C. mrigala. 8. The average weight of the gland is directly related to the state of maturation of the gonads, an observation being recorded here for the first time.

Animals↗
PubMed1976

The morpho-histology of the pituitary glands in two freshwater major carps of India, Labeo rohita (Ham.) and Cirrhinus mrigala (Ham.).

1. The pituitary gland in Labeo rohita and Cirrhinus mrigala is a small, pear-shaped, whitish, soft body situated in a cavity -- the sella turcica. The gland is of the lepto-dorso basic type. 2. It consists of the neurohypophysis and adenohypophysis. The latter comprises three lobes viz., the rostral pars distalis, the proximal pars distalis and the pars intermedia. 3. The neurohypophysis branches into the pars distalis, extends into the pars intermedia and ramifies extensively. It is composed of loosely arranged fibres among which are present nuclei of the neurones and a few droplets of neurosecretory material. 4. The rostral pars distalis is antero-dorsal in position and is the smallest portion of the gland. It consists of two types of acidophils a few cyanophils and chromophobes. 5. The proximal pars distalis occupies the central region and is the largest portion of the gland. It comprises two types of acidophils two types of cyanophils and a few chromophobes. 6. The cyanophils of the proximal pars distalis may also contain acidophilic or cyanophilic globules of varying sizes. These globules may be either situated inside the nucleus or on its periphery. 7. The presence of cyanophilic material in the blood sinuses indicates a possible pathway through which the secretory products are conducted into the general circulation. 8. The pars intermedia is the posterior most region of the gland and is large. It is composed of two types of acidophils and a few chromophobes. During the breeding season some of the cyanophils resent in the pars intermedia behave like the gonadotrophs of the proximal pars distalis.

Animals↗