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Biomedical subjects

S K Varma

Publications and source records attributed to S K Varma.

At least 55 records · Page 3Linked to original sources
PubMed1978

Effect of maternal hypothyroidism and triiodothyronine on the fetus and newborn in rats.

Of 36 adult female rats studied 19 were radiothyroidectomized; 3 weeks later all rats were bred. Radiothyroidectomized rats were divided into Groups I-III. Group I was untreated. Maternal weight gain was not noted until day 9 and was steady thereafter. Group III rats were treated with triiodothyronine up to the first day of pregnancy, but were hypothyroid during gestation (elevated TSH and low T3). Group II rats were treated with T3 up to the day of delivery. The pregnancy, its outcome, and TSH and T3 levels were similar to the normal controls (Group VI). Pregnancy, its outcome, and TSH and T3 levels were not different from controls when T3 was given to normal rats up to day 1 of pregnancy (Group IV). T3 concentrations were elevated in the normal rats which were given T3 continuously up to the day of delivery (Group V). However, the animals did not appear to be thyrotoxic and TSH was not suppressed. The size of the litters of Group I mothers was significantly less than in other groups and this difference may be attributed to an increased tendency to resorb implanted fetuses in untreated hypothyroid mothers. However, activity, day of eye opening weight gain, and TSH and T3 levels of the pups of all the groups were similar up to age 21 days. The data indicate the independence of the fetal pituitary-thyroid axis from maternal thyroidal status in rats.

Animals↗
PubMed1976

Morphology of ovarian changes during the reproductive cycle of the house lizard, Hemidactylus flaviviridis.

Ovarian changes during the reproductive cycle of the oviparous wall lizard (Hemidactylus flaviviridis Rüppel) are described and discussed. It ovulates from mid-March to mid-May with a peak in April. Two eggs, one from each ovary, are ovulated at a time. After the breeding season is over, the ovaries are reduced in size. From June to third week of February they contain small pre-vitellogenic fillicles which start increasing in size with the approach of March when yolk deposition occurs rapidly. The histological details of developing the pre-ovulatory follicles are described. Follicle cell nuclei are taken into the ooplasm of pre-vitellogenic follicles; they are finally absorbed before yolk deposition starts. Pre-ovulatory follicles show highly vascularized thecae and invaginations of the follicular epithelium. Follicular atresia generally occurs in follicles with polymorphic granulosae, in post-ovulatory ovaries. Their granulosa cells give rist to phagocytes which, after removing the ooplasmic contents, degenerate, while the theca interna cells are hypertrophied to form the interstitial gland cells in the walls of degenerated follicles. After ovulation, the granulosa cells hypertrophy to form luteal cell mass filling the follicular cavity. Fibroblasts which appear to arise from the thecal layer, invade the luteal cell mass and form septa. Blood vessels occur in the luteal cell mass. The possible physiological significance of corpora lutea in the wall lizard is discussed.

Animals↗
PubMed1975

Gross morphology of ovarian changes during the reproductive cycle of Indian lizards (Calotes versicolor and Hemidactylus flaviviridis).

A comparative study has been made of the reproductive cycle and gross ovarian changes in two species of Indian lizards (Calotes versicolor and Hemidactylus flaviviridis), which are oviparous. They exhibit a single, short breeding season that extends over a few months. Calotes ovalutes 10 to 32 eggs per clutch (the highest number recorded so far for lizards belonging to the family Agamidae) from last week of June to the first week of September, with July through August being the months of highest reproductive potential when monsoon occurs. From October to May, there occur reduced ovaries containing small previtellogenic follicles which begin to increase in size with the approach of June when heavy yolk deposition occurs. Hemidactylus ovulates from mid-March to mid-May, with a peak in April when there occurs an appreciable increase in day length and temperature. It usually ovulates two eggs per clutch (one from each ovary). From June to the 3rd week of February, the ovaries remain small whitish bodies, each containing 3 or 4 small previtellogenic follicles of variable size which, with the approach of March, begin to increase in size by accumulating yolk. Various indirect evidences suggest that both the lizards lay more than one clutch of eggs during the breeding season.

Animals↗