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Biomedical subjects

J Basu

Publications and source records attributed to J Basu.

At least 91 records · Page 5Linked to original sources

Effect of fatty acid supplementation on thermotropic behavior of membrane lipids and leucine transport in Saccharomyces cerevisiae.

An unsaturated fatty acid-requiring mutant (KD 115) of Saccharomyces cerevisiae shows altered phospholipid composition, transport behavior, and physical properties of membrane lipids when grown in the presence of different cis- and trans-unsaturated fatty acids. There is an increase in phosphatidyl ethanolamine content and a concomitant decrease in phosphatidyl choline content in the cells supplemented with trans-unsaturated fatty acids. The affinity for uptake of L-leucine is higher in the cis-unsaturated fatty acid-supplemented cells compared with the trans-unsaturated fatty acid-supplemented cells. The temperature-dependence of L-leucine uptake bears a reasonably good correlation with the thermotropic behavior of the membrane lipids as studied by the steady-state fluorescence polarization technique. The present findings are discussed in light of the importance of the lipid environment in modulating membrane-associated functions.

Biological Transport

Release of a lectin from a fatty acid auxotroph of Saccharomyces cerevisiae grown in presence of oleic acid.

The unsaturated fatty acid-requiring mutant KD 115 of Saccharomyces cerevisiae secretes a lectin when grown in presence of oleic acid. This lectin is homogeneous on PAGE at pH 8.3, has an approximate molecular weight of 320,000, pI of 4.2 and contains about 60% sugar. It agglutinates chicken and different mammalian erythrocytes, but lyses rabbit red cells only. It is D-galactose-specific. To our knowledge, this is the first report of a hemagglutinin from yeast.

Animals

Plasma vitamin C and uterine cervical dysplasia.

Plasma concentrations of vitamin C were determined in a case-control study of women (n = 80) who had sought a Papanicolaou test in the Bronx Municipal Hospital Center. Controls (n = 34) were women having negative cytologic tests, negative colposcopic findings, and no known gynecologic dysfunction. Cases (n = 46) were defined as women who had either one positive or two consecutive suspicious Papanicolaou smears in a 12-month period. The mean concentration of vitamin C in the plasma was significantly lower in the cases than in the controls (0.36 versus 0.75 mg/dl, p less than 0.0001). Cases were further stratified according to the histopathologic diagnosis. The data direct attention to a possible etiologic association of vitamin C in human cervical epithelial abnormalities. A clinical trial with vitamin C intervention is suggested.

Adult

Chemoprevention of cervix cancer: Phase I-II: A feasibility study involving the topical vaginal administration of retinyl acetate gel.

A Phase I-II clinical trial has been conducted with a retinyl acetate (RA) gel applied cervicovaginally in women having a histopathologic lesion diagnosed as mild or moderate dysplasia. With informed consent, volunteer subjects were observed and followed with Pap smears and colposcopy in a standardized protocol involving a self-administered 7-day treatment course for three successive menstrual cycles. Varying dosages of RA including placebo, 3, 6, 9, and 18 mg per 6 g of an inert vehicle were employed. A total of 50 subjects were monitored for local and systemic side effects. No intolerable side effects or disturbing toxicity was reported or detected at any of these doses. With the 18-mg dosage, significant discomfort was reported by all women. Despite associated side effects and a considerable patient effort involved in carrying out the self-administration of the gel, a high level of compliance was achieved in this trial. It has been established that women will voluntarily participate in an intervention clinical trial to determine whether retinyl acetate is an alternative method of therapy of presumed precancerous lesions of the cervix. The analysis of the side effects of the gel at the various dosage concentrations favors the selection of the 9-mg dosage for a multicenter Phase III clinical trial to determine efficacy.

Colposcopy

Effects of L-lysine administration on certain aspects of ascorbic acid metabolism.

The effects of administration of L-lysine on total ascorbic acid level of various tissues and plasma of rats were studied. The biosynthesis of L-ascorbic acid by the liver tissue was also followed. L-lysine was administered at a dose of 88.3 mg day-1 (20% of LD50) for each 100 g body weight for 14 days. L-lysine administration at the present dose elevated the total ascorbic acid level of liver, kidney, testes, spleen and brain tissues. The plasma total ascorbic acid level was also elevated. The synthesis of L-ascorbic acid from both D-glucuronolactone and L-gulonolactone by the liver was, however, reduced after L-lysine administration. It has been suggested that L-lysine administration at the present dose altered the plasma amino acid pattern which in turn impaired the in vivo synthesis of tissue proteins and, consequently, the synthesis of apoproteins of ascorbic acid-synthesizing enzymes, the D-glucuronoreductase and L-gulonooxidase, were reduced. The elevation in the total ascorbic acid level of extra-hepatic tissues and plasma after L-lysine administration was ascribed to the reduced catabolism and diminished urinary excretion of ascorbic acid.

Animals