Search PubMed⌕ Search

Biomedical subjects

S Chakraborty

Publications and source records attributed to S Chakraborty.

At least 163 records · Page 9Linked to original sources
PubMed1982

Mitogenic action of prolactin on the pancreatic islet cells in the chick.

A histological investigation was made to elucidate whether mammalian (ovine) prolactin can induce mitotic activity in pancreatic islet cell (in splenic lobe) of chicks. Prolactin treatment in different dosages (total dosage: 15, 50 and 100 IU per bird in 10 days) increased the mitotic frequency and also caused hypertrophy in the AF-positive cells of the B-islets in the splenic lobe. The increase in mitotic frequency was uniform for all doses applied. It is suggested that prolactin has a mitogenic action on the pancreatic islet cells of male chicks and that action is possibly not dose-dependent.

Animals↗
PubMed1982

Studies on dimensional characteristics of spermatozoa in pure and strain crosses of White Leghorn cockerels.

Sperm head dimensional characteristics were evaluated in three pure strains (M, N, and P) and three strain crosses (N x P, M x N, and P x M) of White Leghorn cockerels. A total of 120 collections from 24 cockerels were taken. The average sperm head length recorded was 14.58 +/- .09 mu, with an average maximum value of 15.29 +/- .19 mu for spermatozoa from the P x M strain cockerels. The average sperm breadth was found to be .722 +/- .005 mu. Maximum values were found for spermatozoa from the M x N strain cockerels that averaged .735 +/- .004 mu. There was a significant difference (P less than .01) between strains for sperm head length. The P x M strain had a significantly longer sperm head length than the other strains. This may be associated with heterosis. There were no significant differences among strains for sperm head breadth. The mean sperm head area was recorded to be 10.61 +/- .08 mu 2. Maximum sperm head area was observed in semen from P x M strain cockerels (11.03 +/- .15 mu 2). The average sperm head shape was found to be 20.14 +/- .22. There were significant differences (P less than .01) among strains for sperm head area and sperm head shape. The repeatability estimates for all the dimensional characteristics showed that they are highly repeatable traits, indicating that additive gene action is playing an important role in the expression of these traits.

Animals↗
PubMed1982

Cytophysiological responses of the pineal gland to intermale aggression in a wild rat.

Intermale aggression by pairing bandicoot rats (Bandicota bengalensis) in their home cage, continuously for three hours, stimulated the pineal gland activity, cytologically measured by decreasing cell population density and increasing nuclear size of the pinealocytes, in the socially subordinate animals. The pineal gland of the dominant animal was not perceptibly affected by aggression. It is suggested that during aggression, the subordinate rats perhaps suffered from psychosocial stress that might have caused hyperactivity of their pineal gland.

Aggression↗
PubMed1982

Cytophysiological response of the pineal gland to long-term administration of norethisterone (a progestogen-only contraceptive) in rats.

Chronic administration of norethisterone for 75 days caused a marked inhibition of the pineal gland activity of cycling albino rats. In addition to a decrease in the nuclear diameter, possibly the cell size also decreased. The progestin, however, failed to induce mitosis in this gland. It is suggested that prolonged administration of norethisterone exerts untoward effects on the pineal gland function in adult female albino rats.

Animals↗
PubMed1981

Prolactin induced mitotic activity in the anterior pituitary gland of the chick.

The current investigation was undertaken to study whether mammalian prolactin can induce mitotic activity in the anterior pituitary gland in chicks. It was found that intramuscular injections of ovine prolactin (1.5 i.u. and 10 i.u. each daily per bird for 10 days) significantly increased mitotic frequency in the adenohypophysis of juvenile cockerels. It is suggested that ovine prolactin has a mitogenic action on the adenohypophysis of the male chicks and that the reaction may be dose-dependent.

Animals↗
PubMed1980

An improved approach for performance evaluation in lower extremity involvement.

An investigation has been carried out to confirm the relationship between heart rate and energy expenditure in case of normal and lower extremity handicapped persons and, to explore the difference, if any, between both the relationships. Studies have been made on 8 below-knee amputees fitted with patellar-tendon-bearing (PTB) prostheses and 10 normal subjects, taken as two separate groups and also, on 1 below-knee amputee and 1 control subject as individuals. It has been found that a significant difference exists between both the relationships and hence, separate heart rate-energy expenditure relationship is needed to evaluate the performance of lower extremity handicapped in clinics and in industry without going into the cumbersome, clumsy and time consuming methods of estimating physiological cost.

Amputees↗
PubMed1980

The mitogenic action of prolactin on some endocrine organs of chicks.

The aim of the present investigation was to explore the mitogenic action of ovine and bovine prolactin hormones in the thyroid, the parathyroid and the thymus glands of chicks. Both the hormones in lowest dosage (1.5 i.u.) increased the mitotic rate in majority of these organs, but it failed to accelerate the mitotic incidence further or were almost ineffective with the higher dosages (5 i.u. and 10 i.u.). Ovine prolactin showed a higher mitogenic response than that seen with the bovine hormone. It is suggested that prolactin in optimal dosage promotes mitosis in these organs of chicks.

Animals↗