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Biomedical subjects

S Banerjee

Publications and source records attributed to S Banerjee.

At least 559 records · Page 31Linked to original sources
PubMed1984

Covalent hydration: a possible mechanism for aza-arene carcinogenesis.

It is hypothesized that differences in the carcinogenicity of certain aza-arenes and their carbocyclic analogs may originate from the ability of the former to form covalent hydrates. The hypothesis is primarily based on a comparison of the carcinogenicity of several aza-arenes with that of corresponding carbocyclic compounds and of aromatic amines which are structurally related to the hydrated aza-arenes. Additional evidence is provided by the regiochemistry of cytochrome P-450 catalyzed oxidation of quinoline.

Amines↗
PubMed1984

Metabolism of progesterone and testosterone by a Bacillus sp.

Microbial transformations by a Bacillus sp. were employed as a means of preparing potentially important derivatives of progesterone and testosterone. Each microbial metabolite was subjected to structure elucidation employing 1H and 13C nmr, mass spectral and cd analysis. Hplc was used for the determination of the percentages of the metabolites formed. The progesterone metabolites were characterised as 14-hydroxy-4-pregnene-3,20-dione (II), 14-hydroxy-5 alpha -pregnane-3,6,20-trione (III), 11 alpha-hydroxy-5 alpha-pregnane-3, 6,20-trione (IV) and 11 alpha,14-dihydroxy-4-pregnene-3,20-dione (V). The testosterone analogs were identified as 4-androstene-3,17-dione (VII), 17 beta-hydroxy-5 alpha-androstane-3,6-dione (VIII), 14-hydroxy-4-androstene-3,17-dione (IX) and 14, 17 beta-dihydroxy-4-androsten-3-one (X). The availability of the metabolites enabled complete elucidation of their 13C nmr spectra.

Bacillus↗
PubMed1984

The inheritance of constitutive and facultative skin colour.

Observations on skin reflectance were made on 309 endogamous Indian families, for constitutive (medial upper arm) and facultative skin colour (forehead) to investigate which of the two colours is under a rigid control of genetic action. An assessment of data by coefficient of correlation "r" show that facultative colour is inherited more strictly than the constitutive colour.

Adult↗
PubMed1984

Shake flask biodegradation of 14 commercial phthalate esters.

An acclimated shake flask CO(2) evolution test was used to study the biodegradability of 14 commercial phthalate esters that are commonly used as plasticizers. Both CO(2) evolution (ultimate biodegradation) and loss of parent phthalate esters (primary biodegradation) were measured. With only a few exceptions, primary biodegradation was 90% or higher, and ultimate biodegradation was in excess of 55% of theoretical results in 28 days. The results showed that all of the commercial phthalate esters were susceptible to biodegradation by mixed populations of microorganisms from natural sources. The results also provide considerable insight into the utility and reproducibility of a standard biodegradation test that is being recommended for widespread screening of chemicals.

Journal Article↗
PubMed1984

Physiology of a temperature-sensitive mutant of Saccharomyces cerevisiae defective in phosphofructokinase activity.

In this paper, we describe a temperature-sensitive mutant of the yeast Saccharomyces cerevisiae (P5-9) which at a restrictive temperature (36 degrees C) shows a pleiotropic defect for transport of many different metabolites. The temperature sensitivity of the mutant is closely related to a reduction in phosphofructokinase activity. This conclusion is based on the following criteria. (i) Both the primary isolate, designated P5-9 (ts [rho-] Ino-), which is an inositol auxotroph and respiration deficient, and a purified derivative, SB4 (ts [rho+] Ino+ ), which is respiration competent and capable of growing in the absence of inositol, are temperature sensitive for growth and ethanol production in media containing glucose or fructose as the sole carbon source. (ii) The respiration-competent derivative SB4 is not temperature sensitive in media containing glycerol or glycerol-pyruvate; glucose inhibits its growth at 36 degrees C in these media. (iii) Assays of glycolytic enzymes in P5-9 and SB4 extracts, prepared from cells incubated for 1 to 2 h at 36 degrees C before harvesting, show selective reduction in phosphofructokinase activity. Analysis of tetrads derived from the cross of mutant and nonmutant haploids indicates that temperature sensitivity for growth is due to a single gene or to two closely linked genes. The biochemical analysis of spores from seven such tetrads revealed a uniform cosegregation of temperature sensitivity for growth and phosphofructokinase activity. Transport and ATP levels were drastically reduced in SB4 cells incubated at 36 degrees C for 1 to 2 h with glucose as the carbon source, but not when glycerol-pyruvate or lactate was the energy source. Therefore, depletion of energy as a result of phosphofructokinase inactivation appears to be the cause of the pleiotropic transport defect observed in the mutant.

Adenosine Triphosphatases↗
PubMed1984

Pigmentary fluctuation and hormonal changes.

Skin colour was determined by reflectance spectrophotometry at 426, 550 and 685 nm wavelength. The data is interpreted by converting 426 and 685 nm into logarithmic and antilogarithmic values. The study indicates the existence of sexual diamorphism in colour. Further, the variability in pigmentation is also not similar in both sexes.

Adolescent↗
PubMed1983

Evidence for binding of metabolically activated 1,2-dibromoethane to chromatin of forestomach and liver.

The covalent binding of metabolically activated 1,2-dibromoethane (DBE), a potent carcinogen, to chromatin constituents of forestomach and liver was examined in vitro. Chromatin was prepared from forestomach and liver of B6C3F1 mice and characterized. In order to activate DBE, microsomes and cytosol were isolated from mouse forestomach and liver and incubated with [14C]-DBE in the presence of a NADPH regenerating system. Results demonstrate that DBE bound covalently to the same extent to protein of microsomes and chromatin isolated from forestomach and liver. On the contrary, DBE bound significantly more to chromatin DNA of forestomach or liver than it did to salmon sperm DNA. It appears from these results that the metabolically activated DBE is more reactive to homologous DNA than exogenous DNA. Fractionation of DBE-bound chromatin protein into histone and nonhistone proteins resulted in higher binding of DBE to nonhistone than to histone proteins isolated from forestomach and liver.

Animals↗
PubMed1983

On the processing of saliva samples for progesterone assay.

Reports from several laboratories indicate that the concentration of progesterone in the saliva provides a valid indicator of corpus luteum function. However, optimal conditions for the treatment and storage of saliva specimens prior to analysis was not addressed in these papers. We have found that 1) sonication of saliva in brief bursts produces a homogeneous sample from which progesterone is removed quantitatively by a single extraction with hexane in a vortex mixer, and 2) prompt freezing of saliva is important since storage of samples at room temperature for 48 hours results in a significant decrease in radioimmunoassayable progesterone. Four normal women provided daily saliva specimens throughout one menstrual cycle and serum samples every 3 days during the luteal phase. Excellent correlations between the progesterone profiles in the two fluids were obtained.

Adult↗
PubMed1983

Regiochemistry of Camphor Analog Oxidation by Pseudomonas putida.

Pseudomonas putida cooxidized norcamphor and pericyclocamphanone to hydroxylated and lactonized products during growth on camphor. Norcamphor was hydroxylated at the 5 position, similar to the corresponding process in camphor, but pericyclocamphanone was oxidized at the 6 position. We conclude that the regiochemistry of the hydroxylation may be substrate controlled.

Journal Article↗
PubMed1983

Normal values for interpupillary, inner canthal and outer canthal distances in an Indian population.

Interpupillary distance (IP), inner and outer canthal distances (IC, OC) have been investigated in an Indian population to establish normal values for these parameters. In males, the mean values of IC and OC were found to be 3.15 +/- 0.2445 and 8.44 +/- 0.3172 cm, respectively. However, in females these values were 3.09 +/- 0.2862 and 8.17 +/- 0.3310 cm, respectively. IP, as derived by Pryor's formula, was found to be in close proximity with the observed IP values. IP was also estimated by a multiple linear regression technique. The normal IP values are useful in the identification of ocular hypo- or hypertelorism in various syndromes which might be otherwise obscured by the various somatometric traits of the face.

Adolescent↗
PubMed1982

Immunoglobulin-lipid interaction. A model membrane study.

We recently presented evidence (Vandenbranden, M., De Coen, J.L., Jeener, R., Kanarek, L. and Ruysschaert, J.M. (1981) Mol. Immunol. 8, 621-631) for the existence of two conformational rabbit serum IgG immunoglobulin isomers. In the present report, their capacity to interact with lipid is investigated in model membranes. (1) One isomer, IgG(H), behaves like several intrinsic membrane proteins: it induces a large surface pressure increase when injected under a lipid monolayer in the close packed state and increases by 20-fold the conductance of a planar bilayer. The other isomer, IgG(S) doesn't interact significantly with the lipids. (2) IgG(H) marked a preference for monolayers made of lipids with a negatively charged polar headgroup and bearing unsaturations in their acyl chains. Penetration is stronger with lipid monolayer in the fluid state than in the rigid state. (3) As previously shown (Vanderbranden, M., De Coen, J.L., Jeener, R., Kanarek, L. and Ruysschaert, J.M. (1918) Mol. Immunol. 18, 621-631), circular dichroïsm spectra and antigen precipitation tests don't allow to detect any difference in the overall secondary conformation and antigen recognition properties of the two isomers. (4) Papaïn cleavage of the hinge region suppresses the hydrophobic properties of IgG towards lipid monolayers. (5) The hypothesis of a binding of the hinge region with the lipid bilayer is discussed.

Animals↗