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Biomedical subjects

R Prasad

Publications and source records attributed to R Prasad.

At least 19 recordsLinked to original sources
PubMed1979

Resolution of the charge forms and amino acid sequence and location of a tryptic glycopeptide in rat alpha-lactalbumin.

Three charge forms of rat alpha-lactalbumin were separated by ion exchange chromatography on DEAE-cellulose. The amino acid composition of each form was similar but they differed in carbohydrate composition. Each form contained a tryptic glycopeptide having a common polypeptide and heteropolysaccharide unit. The tryptic glycopeptide was sequenced and positioned in rat alpha-lactalbumin, which was partially sequenced from residues 1 to 50. The carbohydrate attachment site was at Asn45. Secondary structure calculations predicted that Asn45 is in a beta bend conformation whereas Asn45 in bovine alpha-lactalbumin, a poorly glycosylated protein, is not in a bend conformation.

Amino Acid Sequence↗
PubMed1979

Aryl hydrocarbon hydroxylase inducibility in lung cancer patients undergoing radiotherapy.

Aryl hydrocarbon hydroxylase (AHH) inducibility was studied in cultured lymphocytes from 21 healthy control subjects and from 15 lung cancer patients selected for radiation therapy. AHH inducibility of the patients was measured prior to, during and at the end of radiation therapy. Four of 15 patients had values comparable to the healthy controls. Cellular DNA and protein measurements of cultured lymphocytes were the same for patients and healthy controls. There was no significant difference in the percentage of lymphoblast formation and percentage of cell survival between the two groups. Radiation therapy reduces the number of lymphocytes in vivo and the amount of lymphoblast formation in vitro. AHH inducibulity is signifcantly lowered by radiation in the patients who had very high inducibility at pre-treatment level. DNA and protein contents of cultured lymphocytes did not change during radiation therapy.

Aged↗
PubMed1979

An inducible proline transport system in Candida albicans.

1. When Candida albicans cells were preincubated with proline or grown in the presence of proline as the sole nitrogen source they exhibited a rapid increase in the influx of proline (the inducible transport system). 2. The induction appeared to be specific for proline and also demonstrated in other Candida species. 3. Both the inducible and constitutive proline uptake systems exhibited similar characteristic features. 4. The nature of the inducer for proline uptake in C. albicans appeared to be free proline. 5. The development of the inducible proline transport system was dependent on concomitant synthesis of RNA and protein and the induction was not affected by glucose or any other carbon sources used.

Amino Acids↗
PubMed1979

The effect of altered ergosterol content on the transport of various amino acids in Candida albicans.

Candida albicans cells have low levels of ergosterol when grown in ascorbic acid-supplemented media. When cells are grown in hydroquinone-supplemented media, the ergosterol levels became higher as compared to normal cells. The uptake of lysine, glycine, glutamic acid, proline, methionine and serine is reduced in hydroquinone-supplemented cells. In contrast to hydroquinone-supplemented cells, the rate and level of accumulation of these amino acids are higher in ascorbic acid-supplemented cells. Nystatin-resistant isolates of C. albicans with low ergosterol contents also exhibit an increased rate and level of accumulation of these amino acids. The uptake of phenylalanine and leucine remained unaffected by such a change in ergosterol levels brought about by different supplementation of the media. The results demonstrate a correlation between ergosterol levels and amino acids uptake. Contrary to various reports, the rate of K+ efflux does not seem to correlate with the amino acid uptake in C. albicans cells.

Amino Acids↗
PubMed1979

Aryl hydrocarbon hydroxylase inducibility and lymphoblast formation in lung cancer patients.

Aryl hydrocarbon hydroxylase (AHH) inducibility and lymphoblast formation were studied in lymphocytes from healthy control subjects and from lung cancer patients undergoing radiotherapy. The relationship between AHH inducibility and percentage lymphoblasts was statistically significant only for the pre-treatment patients (r = 0.598; p less than 0.05). In the control group and in patients undergoing radiotherapy the correlation between AHH inducibility and lymphoblast formation was positive but statistically it was not significant. Our data do not suggest a linear relationship between AHH inducibility and lymphoblast formation.

Aryl Hydrocarbon Hydroxylases↗
PubMed1979

alpha-I antitrypsin enzyme deficiency in Indian childhood cirrhosis.

Antitrypsin activity was measured in 50 healthy controls and 100 cases of Indian Childhood Cirrhosis (ICC). The incidence of alpha-I anti-trypsin (Alpha I-AT) enzyme deficiency was strinkingly higher in cases of cirrhosis (39.0%) than in healthy controls (4%). The enzyme deficiency was more prevalent in severe grades of cirrhosis (51.5%) as compared to mild (17.6%) and moderate cirrhosis (38%). Liver function tests were severely deranged in enzyme deficient cirrhotics and the damage to the liver was directly proportional to the extent of the enzyme deficiency. The incidence of the family history of ICC was noted significantly higher in enzyme deficient cases (20%) as compared to non-deficient cases (3.3%). The enzyme deficiency was also measured in 160 first blood relatives of the deficient cirrhotics and was found to be deficient in 19.4% subjects. It is probable that the deficiency runs in families with an autosomal recessive mode of inheritance.

Child↗
PubMed1979

Lipid composition and polyene antibiotic sensitivity in isolates of Candida albicans.

When Candida albicans cells were grown on hydroquinone (Hy cells) or ascorbic acid (As cells) supplemented media, they exhibited a 26% rise and 16% drop in ergosterol content, respectively. C. albicans cells manifested a gradual increase in total lipid levels, when they were grown on n-alkanes of different chain lengths. The magnitude of the nystatin effect (in terms of proline uptake and K+ efflux) was more pronounced in cells having more ergosterol (Hy cells) compared with the cells having low levels of ergosterol (As cells), suggesting a correlation between nystatin sensitivity and ergosterol content of the C. albicans cells. However, such correlation could not be demonstrated in alkane grown cells where levels of different lipids were variable. Results demonstrated that several other lipids besides sterol may also influence the polyene antibiotic sensitivity in C. albicans cells.

Candida albicans↗
PubMed1978

Characteristics of proline transport in normal and starved cells of Candida albicans.

1. There was no apparent correlation between the rate of respiration and rate of accumulation of proline in Candida albicans cells. 2. In contrast to normal cells, the respiration in the starved cells became completely cyanide insensitive. The starvation of cells in the presence of cycloheximide prevented the cells from becoming cyanide insensitive. The addition of Fe(III), however, accelerated the process. 3. Oxidizable substrates e.g. NADH, acetate and glucose, when added to cyanide-insensitive starved cells, exhibited 40--280% stimulation in respiration rate. However, this enhancement in oxidation by various substrates was not coupled to a simultaneous increase in the proline uptake or in intracellular ATP levels. 4. There was 6-fold stimulation in proline uptake when cyanide-insensitive cells were preincubated with 50 mM glucose. The preincubation of starved cells resulted in a partial restoration of cyanide sensitivity and increased intracellular ATP levels. The preincubation of starved cells with other oxidizable substrates resulted in a partial restoration of cyanide sensitivity but had no stimulatory effect on intracellular ATP levels and proline accumulation. 5. Both the enhanced uptake and ATP levels in glucose preincubated cells were found to be completely abolished by iodoacetate. 6. It is proposed that the increased proline uptake in cells preincubated with glucose was mainly due to the production of glycolytic energy.

Adenosine Triphosphate↗
PubMed1978

Variation in the lactase dehydrogenase activity of the esophagus.

Quantitative assay and electrophoretic study of lactate dehydrogenase (LDH) from various tissues of the opossum esophagus were performed. On the basis of expression of the LDH isozymes, we concluded that the smooth muscle of the body of the esophagus carry on more anaerobic glycolysis than the striated muscle. The smooth muscle of the gastroesophageal junction carry on both anaerobic as well aerobic glycolysis.

Animals↗