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Biomedical subjects

C R Murti

Publications and source records attributed to C R Murti.

At least 37 records · Page 2Linked to original sources

Preliminary evidence for the presence of glutathione-s-transferase activity in mammalian and avian brain.

Glutathione-S-transferase activity has been demonstrated in the brain of rabbit, guinea pig, rat, mouse, and pigeon. The activity was in the following order: rabbit > (guinea pig = mouse) > rat > pigeon. The activity of brain was about 1/3 to 1/9 of that present in liver depending upon the species. In the rat brain glutathione-S-transferase activity was found to be distributed equally in cerebrum, cerebellum, and brain stem and localized mainly in the organelle-free cytosol fraction.

Animals↗

Organochlorine pesticide residues in some Indian wild birds.

Residues of BHC and DDT were estimated by gas-liquid chromatographic analysis of the internal body organs, depot fat, and blood plasma of a few species of Indian wild birds, captured in and around the urban area of Lucknow. Total BHC and gamma-BHC (lindane) levels were high in breast muscle, liver, heart, and lung tissues of pigeon, crow, and vulture, compared with the respective tissues of chicken, cattle egret, and kite. More lindane and total BHC was found in tissues of vulture compared with other species. The major part of BHC isomers in the brain of birds examined was accounted for by alpha-BHC. Total BHC detected in depot fat of crows was 29.7 ppm; lesser amounts were found in vulture, kite, and cattle egret, respectively. Total DDT levels were comparable in the blood plasma of chicken, pigeon, crow, and cattle egret, although residues generally showed the following order in the tissues examined: chicken less than pigeon less than cattle egret less than crow less than kite less than vulture. High levels of DDT were detected in depot fat of crow, kite, and vulture (50.8, 67.0 and 95.3 ppm, respectively). Avian species thus reflect biological magnification of BHC and DDT residues, presumably due to their food habits.

Animals↗

Chlorinated hydrocarbon pesticides in blood of newborn babies in India.

Umbilical cord blood collected during labor of 100 Indian women was analyzed for organochlorine pesticides by gas-liquid chromatography with electron-capture detection. Significant levels of p,p'-DDT and its metabolites, p,p'-TDE and p,p'-DDE, as well as alpha-, beta-, and gamma-isomers of BHC were estimated. Residues in the neonatal blood were related to age, dietetic habits, and area of residence of the mothers. The study highlights the extent of placental transfer of the body burden of toxic chemicals from the mother to the fetus.

Adolescent↗

Trace elemental analysis of extracted dust from lungs and lymph nodes of domestic animals using X-ray fluorescence technique.

Samples of dust extracted from the lungs and lymph nodes of certain domestic animals from West Bengal, Orissa, Bihar provinces of India were quantitatively analysed using photon excited energy dispersive X-ray fluorescence technique. Thin specimens were prepared for analysis to minimize matrix enhancement and absorption effects. Amongst the various elements analysed, Hg, Fe, Cu, Zn and Pb were found to be present in appreciable amounts. An important finding was the presence of a very high concentration of Hg in extracted dust samples from West Bengal. The significance of the various results obtained in this investigation is discussed.

Animals↗

Role of human skin in the photodecomposition of bilirubin.

1. Human skin epithelium and human skin were found to absorb both free bilirubin and serum-bound bilirubin from an aqueous buffered medium. The serum-bound bilirubin thus absorbed was readily released when human skin epithelium or human skin were transferred to media containing no bilirubin. 2. The K(m) values for serum-bound bilirubin were 1.8x10(-3)m and 2.2x10(-3)m respectively for human skin epithelium and human skin; corresponding K(m) values for free bilirubin were 3.0x10(-4)m and 5x10(-4)m. The V(max.) for bound and free bilirubin was of the same magnitude, the apparent V(max.) being 1.0 and 1.66mumol/g of tissue for human skin epithelium and human skin respectively. 3. When human skin that had acquired a yellow tinge by absorbing bilirubin was incubated in a buffered medium and exposed to a mercury-vapour light, the yellow colour disappeared and decomposition products of bilirubin accumulated in the medium. 4. Experiments with [(3)H]bilirubin indicated that the pigment absorbed by skin was photo-oxidized to products that were soluble in water and the quantity and number of such products increased with the time of exposure of human skin to the light-source. Under similar conditions [(3)H]bilirubin alone in buffered medium was also oxidized and gave products which by paper chromatography appeared to be different from those released by human skin that had absorbed bilirubin. 5. The results suggest that by virtue of its large surface area human skin can act as a matrix for the degradative action of light on bilirubin.

Adult↗

Effect of high- and low-protein diets on the regulation of rat liver tyrosine aminotransferase and tryptophan oxygenase activities by L-tyrosine and L-tryptophan.

Induction of rat liver tyrosine aminotransferase by l-tyrosine and tryptophan oxygenase by l-tryptophan was studied in groups of rats fed on diets containing 18 or 5% protein. The basal activity of hepatic tyrosine aminotransferase of rats receiving 5% protein gradually increased with the age of the animals but that of rats receiving 18% protein did not. l-Tyrosine induced hepatic tyrosine aminotransferase in rats receiving 18% protein when tested at ages from 4 to 20 weeks. When induction by l-tyrosine was carried out in rats receiving the 5% protein diet, significant induction of tyrosine aminotransferase occurred only in 4- or 6-week-old rats. Induction by l-tryptophan of tryptophan oxygenase in liver or the basal activity of this enzyme in liver did not differ between the groups fed on 5 and 18% protein. On changing the diet from 0 to 18% protein, the above-mentioned effects on the induction of hepatic tyrosine aminotransferase were reversed.

Animals↗

Uptake and release of bilirubin by skin.

1. Skin epithelium of albino rat, mouse and guinea pig was shown to accumulate bilirubin from a medium containing free or bound bilirubin. 2. The K(m) values for bound bilirubin were 2.22x10(-3), 1.33x10(-3) and 9.5x10(-4)m for rat, mouse and guinea pig respectively and the corresponding K(m) values for free bilirubin were 5.2x10(-4), 4.0x10(-4), 1.8x10(-4)m; the V(max.) values of bound and free bilirubin were unchanged. 3. The uptake showed saturation kinetics. Bound bilirubin was released together with serum proteins. Free bilirubin bound to skin was not released into the medium. 4. Freezing and thawing of skin epithelium did not cause any significant lowering of the uptake of bilirubin but heat-denatured skin epidermis took up only 50% of the bound bilirubin or free bilirubin taken up by control unheated skin epithelium. 5. The uptake of free and bound bilirubin was prevented by HgCl(2) but not by sodium arsenate, NaCN, NaF, cycloheximide, 2,4-dinitrophenol or iodoacetate. 6. Most of the free bilirubin was bound to the lipids or lipoprotein fraction of skin epithelium and could be extracted by solvents. 7. Rat skin showed the highest accumulation and efflux of bilirubin.

Animals↗