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Biomedical subjects

M Chatterjee

Publications and source records attributed to M Chatterjee.

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

Valine production from hydrocarbon by Micrococcus varians.

A bacterium isolated from Assam (India) soil was found to accumulate L-valine in the growth medium and was identified as Micrococcus varians. The strain grew and accumulated valine in a purely synthetic medium, but supplementation with either casamino acids or yeast extract or with both, improved the yield. The entire fermentation period could be divided into a growth phase and a production (phase which could be prolonged by adjustment of pH to neutral range. Among the different hydrocarbon and nitrogen sources tested straight run gas-oil and ammonium sulphate, respectively, were found most suitable. Antibiotics inhibited growth but stimulated extracellular valine accumulation. Vitamins stimulated growth and valine yield and an inoculum level of 10% was found to be optimal. The yield of L-valine under optimal conditions was 2.95 g/L.

Anti-Bacterial Agents↗
PubMed1982

Influence of hormones on N-(4-hydroxyphenyl) retinamide inhibition of 7,12-dimethylbenz[alpha]anthracene transformation of mammary cells in organ culture.

Influence of estrogen and progesterone on the inhibitory action of N-(4-hydroxyphenyl) retinamide (4-HPR) was examined during the promotional stage of 7,12-dimethylbenz[alpha]anthracene (DMBA) transformation of the epithelial cells in culture of the whole mammary organs of BALB/c mice. In medium containing insulin, prolactin, hydrocortisone, and aldosterone, 4-HPR caused 68% inhibition of transformation as determined by the presence of nodule-like alveolar structures in the glands exposed to DMBA in vitro. Addition of estrogen and progesterone to the medium reduced this pronounced inhibitory action of 4-HPR to only 15%. While the medium containing insulin, prolactin, growth hormone, estrogen and progesterone was highly conducive to DMBA transformation, 4-HPR inhibition of transformation was limited to only 21%. The antagonistic action of the ovarian steroid hormones was present also at the level of frequency of nodule-like alveolar lesions (NLAL) per gland. Although both ovarian hormones reduced the inhibitory action of 4-HPR, on mammary cell transformation, the antagonistic action of estrogen was noticeably more pronounced.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1982

N-Nitrosodiethylamine-induced nodule-like alveolar lesion and its prevention by a retinoid in BALB/c mouse mammary glands in the whole organ in culture.

The ability of N-nitrosodiethylamine (DENA) to induce transformation of the mammary cells was studied in culture of the whole mammary organ from BALB/c female mice. Incidence of nodule-like alveolar lesions (NLAL) in the glands in vitro has been as a measure of transformation. NLALs are analogous to the precancerous hyperplastic alveolar nodules (HAN) of mouse mammary gland in vivo. The mammary glands were treated with graded concentrations (0.1-2.5 microgram/ml) of DENA during lobuloalveolar morphogenesis in medium (Waymouth's MB752/1) containing insulin, prolactin, hydrocortisone and aldosterone. DENA treatment caused a dose-related increased occurrence of NLAL in the glands in vitro and concentration of 1.5 microgram/ml produced the highest incidence of 85%. The high incidence of NLAL was accompanied by a 3-fold increase of DNA repair activity in the DENA treated glands. Incubation of the glands for 6 days after DENA treatment in medium containing N-4-hydroxyphenyl)retinamide and the same hormone mixture caused 61% inhibition of NLAL incidence. The results indicate that DENA is capable of inducing a high level of transformation of the mammary epithelial cells in vitro and that this retinoid can inhibit expression of the transformed cells acting at the promotional level.

Animals↗
PubMed1977

Microheterogeneity of human placental lactogen showing different patterns in individuals.

Samples of human placental lactogen, obtained either as a standard pooled preparation or prepared from individual placentas, were shown to migrate as a single band on acrylamide gel electrophoresis. When subjected to isoelectric focusing in polyacrylamide gels, the pooled sample was resolved into bands at pI values 5.0, 5.5, 5.8. 6.0, 6.1 and 6.2. Different batches of the standard pooled sample gave different proportions of each isoprotein species. Isolation and refocusing of individual bands did not alter the pI of each. Treatment with urea or with p-chloromercuribenzoate did not eliminate microheterogeneity seen on isofucising, indicating that the observed heterogeneity is probably not due to conformational differences or to restriction of molecular shape of disulfide bonds. It was shown by immunodiffusion that all the isofocusing reacted similarly against a common antibody to human placental lactogen. When placental lactogen was extracted from individual full term human placentas, the same isoprotein bands were observed but their proportions varied markedly from one placenta to another, and not all bands were present. Thus human placental lactogen displays considerable microheterogeneity which varies with individual placentas.

Electrophoresis, Polyacrylamide Gel↗
PubMed1976

Synthesis of human placental lactogen and human chorionic gonadotropin by polyribosomes and messenger RNA's from early and full term placentas.

Synthesis of human placental lactogen (hPL) and of human chorionic gonadotropin (hCG) by membrane-bound and free polyribosomes from early and from full term human placentas was investigated by in vitro release of the nascent hormone peptides, followed by immunoprecipitation and electrophoresis in sodium dodecyl sulfate gels, and by specific binding of 125I-labeled hPL antibody to nascent peptide chains. In addition, messenger RNA'S Were extracted from total, free, and membrane-bound placental polyribosomes and their capacities for hPL and hCG synthesis were measured in a heterologous cell-free system prepared from wheat germ. Membrane-bound polyribosomes from full term placentas were several times more active in the synthesis of both peptide hormones than were free polyribosomes. By binding 125I-labeled hPL antibody to nascent chains on the polyribosomes, it was determined that hPL is made by clusters of seven to nine ribosomes. About 8% of the nascent peptide chains released by incubation of polyribosomes from full term placentas was accounted for by hPL, and 2% by hCG. In contrast, no chains of hPL were released by polyribosomes from 10-week placentas, whereas 11% of the total released chains were accounted for by hCG. When messenger RNAs prepared from the polyribosomes of 20- and 40-week placentas were used to stimulate protein synthesis in a wheat germ system, hPL accounted for 0.4 and 2%, respectively, of total protein synthesis, while hCG was 8 and 2%, respectively. This confirmed the relative proportions observed for nascent chains on the polyribosomes of early and late placentas. Unexpectedly, translation of mRNA from free polyribosomes yielded as much hPL and two-thirds as much hCG as did translation of mRNA from bound polyribosomes. We conclude, that the decreased blood levels of hCG and increased blood levels of hPL with advancing gestational age reflect the relative in vitro rates of synthesis of these hormones by placental polyribosomes, the abundance of which is determined by availability of their respective messenger RNAs at different times in gestation.

Animals↗
PubMed1975

Lymphocyte response to autologous tumor antigen(s) and phytohemagglutinin in ovarian cancer patients.

Peripheral blood lymphocytes from 11 patients with ovarian carcinoma were incubated several times with autologous tumor extract as well as phytohemagglutinin (PHA) at different concentrations. Lymphocytes from 10 normal, healthy, age-matched females were also studied similarly. Tritiated thymidine incorporation into DNA of transformed lymphocytes was measured. No significant response was obtained with lymphocytes from ovarian cancer patients or normal individuals in the presence of tumor extracts. Of 6 tumor extracts tested, 5 did not have any cytotoxic effect on autologous or on homologous normal healthy lymphocytes. Hence, with this test system employed, no evidence for a cell-mediated immunity to autologous tumor in ovarian cancer patients was observed. PHA, on the other hand, induced vigorous blastogenic response in several ovarian cancer patient's lymphocytes, as well as in all normal healthy lymphocytes, indicating no inherent defect in the T-lymphocyte system of ovarian cancer patients. Only 2 of the patients, when tested for delayed hypersensitivity reaction against a battery of recall antigens and keyhole limpet hematocyanin, were completely anergic. None of the patients responded when skin tested with their own tumor extracts.

Antigens, Neoplasm↗