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Biomedical subjects

S Chari

Publications and source records attributed to S Chari.

50 records · Page 3Linked to original sources
PubMed1983

Inhibition of progesterone secretion in cultured human granulosa cells by a low molecular weight fraction of human follicular fluid.

Previous studies demonstrated that a low molecular weight peptide fraction (G10-3) from human follicular fluid (FFl) could inhibit steroidogenesis by rat granulosa cells in vitro. In the present study this FFl fraction was tested upon human granulosa cells. The G10-3 fraction (less than 1000 mol wt) was obtained by sequential gel filtration on Sephadex G50 and G10 of a steroid-free extract of a pool of human FFl collected from various-sized follicles at different stages of the menstrual cycle. Human granulosa cells were obtained from large, healthy follicles in the mid- to late follicular phase of eight patients, and cultured for 4-6 days in the absence or presence of G10-3. In all cases G10-3 produced a dose-dependent inhibition of basal progesterone secretion and, when tested, also of FSH-stimulated progesterone secretion. Inhibition of progesterone secretion appeared to be greater in cells obtained from less mature follicles as compared to cells obtained from follicles that were periovulatory. The results suggest the presence of a low molecular weight luteinizing inhibitor in human FFl.

Body Fluids↗
PubMed1979

Study of testicular feedback in male rats using artificial cryptorchidism as a model.

Plasma LH, FSH and testosterone were measured in testosterone-treated and untreated cryptorchid and castrated male rats. Exogenous testosterone prevented the increase in basal LH but not FSH levels seen in the untreated cryptorchids. Increases in plasma LH and FSH in response to LH-RH were greater in the cryptorchid as compared to the control group and this could not be reversed by exogenous testosterone, suggesting that spermatogenesis-related feedback factors regulate LH as well as FSH at the pituitary level in the intact rat. The results were consistent with a reduced but nevertheless significant secretion of inhibin by the cryptorchid testis. Basal plasma testosterone levels and ventral prostate weights were not significantly different from intact animals.

Androgens↗
PubMed1979

Purification of "inhibin" from human ovarian follicular fluid.

Following the earlier demonstration of inhibin-like activity in human ovarian follicular fluid a method for its purification to apparent homogeneity is described. The fluid was converted to acetone powder and subjected sequentially to ammonium sulphate fractionation, gel chromatography on Sephadex G-200, continuous gradient ion-exchange chromatography on DEAE-cellulose, first with a pH gradient from 8.0 to 4.0 and then with a NaCl gradient to 1 M at pH 5.2. The active fraction from this step was subjected to gel filtration on Sephadex G-100 and finally passed through an Amicon Centriflo membrane CF-25 (cut off point: 25,000 m.w.). The ultrafiltrate was homogeneous by SDS-polyacrylamide gel electrophoresis, had a molecular weight of the order of 23 000 and was capable of suppressing serum gonadotrophin levels in the castrated male rats in as low a dose as 25 microgram/rat.

Adult↗
PubMed1978

[Inhibin-like activity in human ovarian follicular fluid (author's transl)].

A steroid-free proteinaceous substance with inhibin-like activity has been extracted from human ovarian follicular fluid by alcohol precipitation. This substance was capable of inhibiting the ovarian weight increase of hCG-treated immature female rats and also of suppressing the post-castration rise of serum FSH levels in immature male rats. Follicular fluid from small follicls obtained from regularly cycling women was--on the basis of protein- found to be more active than cystic follicular fluid obtained from a premenopausal woman. The possible role of inhibin in the regulation of human ovarian cycle has been discussed.

Animals↗
PubMed1977

Chemistry and physiology of inhibin--a review.

Several reports have appeared on the presence of inhibin, the second testicular hormone postulated by McCullagh, in such sources as testicular extracts, seminal plasma, rete testis fluid, spermatozoa as well as ovarian follicular fluid. The resurgence, in recent years, of interest in the physiology of inhibin is reviewed in the historical perspective of earlier work. This survey presents an outline of the general findings on the nature and characterization of this substance. Studies relating to its exact site of production as well as its site of action are briefly described and discussed.

Animals↗
PubMed1976

A convenient and rapid bioassay for inhibin.

A bioassay for inhibin, based on a dose-dependent suppression of HCG-induced ovarian weight increase in intact, immature female rats, is described. The method is specific and has acceptable sensitivity and precision such that it lends itself to statistically valid quantitative assay of inhibin activity. Being a 24-hour assay, it is conveniently and rapid performed as well as being a multiple bioassay for estimating potencies of various preparations.

Animals↗
PubMedDate not supplied

Radiological appearance of pancreatic calculi in tropical versus alcoholic chronic pancreatitis.

Tropical and alcoholic forms of chronic pancreatitis differ in their clinical, aetiological and epidemiological features. We compared the radiological appearances of pancreatic calculi seen on plain roentgenogram of the abdomen of 89 patients with tropical calcific pancreatitis (TCP) and 32 patients with alcoholic calcific pancreatitis (ACP) seen in Madras, Southern India. While TCP was characterized by the frequent occurrence of large, discrete, dense calculi, patients with ACP had typically small, speckled calculi with irregular, hazy margins. The calculi in TCP resembled those described for hereditary pancreatitis. This is the first report comparing the radiological appearances of TCP and ACP patients seen at the same centre.

Adult↗
PubMedDate not supplied

Faecal chymotrypsin assay in tropical and alcoholic chronic pancreatitis.

Faecal chymotrypsin (FCT) levels were estimated in a group of patients with tropical chronic pancreatitis (TCP) and compared with patients with alcoholic chronic pancreatitis (ACP), 'gastrointestinal' controls and 'healthy' subjects. Exocrine pancreatic insufficiency as assessed by low faecal chymotrypsin levels (less than 5.8 mu/g) were present in 85.7 per cent of TPC and 84.6 per cent of ACP patients. Mean FCT levels as well as the distribution of FCT values were similar in TCP and ACP patients and significantly lower than the two control groups (P less than 0.001). There was also no difference with respect to mean FCT levels between subgroups of TCP patients with and without diabetes and those with and without calcification. Faecal chymotrypsin assay is a simple test for diagnosis of chronic pancreatitis in gastroenterological centres in tropical countries.

Alcoholism↗