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Biomedical subjects

R Prasad

Publications and source records attributed to R Prasad.

At least 343 records · Page 19Linked to original sources
PubMed1980

Lymphocyte replication in lung cancer patients undergoing radiotherapy.

In vivo and in vitro survival and response of lymphocytes were studied in 12 lung cancer patients before, during and following radiotherapy, and comparisons were made to data from 20 healthy control subjects. Lymphocyte counts of lung cancer patients prior to radiotherapy did not differ significantly from those of control subjects. Following radiotherapy, lymphocyte counts were significantly reduced. The in vitro survival of lymphocytes from lung cancer patients prior to radiotherapy was lower than that of normal controls. Radiation treatment had no effect on lymphocyte survival in vitro. PHA-stimulated lymphoblast formation in lung cancer patients prior to radiotherapy did not differ from that of normal controls, but decreased significantly during radiotherapy.

Cell Survival↗
PubMed1980

Catecholamine metabolism in pargyline treated rats exposed to stress.

The administration of pargyline to normal rats enhanced the adrenal catecholamines noradrenaline + adrenaline content, tyrosine hydroxylase (TH) and catechol -0-methyl transferase (COMT) activity together with a reduction in monoamine oxidase (MAO) activity. The pargyline pretreated rats exposed to acute stress exhibited a significant increase in adrenal catecholamine content and COMT activity with no change in TH and phenylethanolamine-N-emthyl transferase (PNMT) activity as compared to normal stressed rats. However, adrenal MAO activity was decreased in pargyline pretreated stressed rats. Thus, these observations tend to suggest that pargyline treatment before exposure to stress considerably influence the usual stress response in term of catecholamine metabolism.

Adrenal Glands↗
PubMed1980

Radioimmunoassay for detection of latent chronic alcoholic pancreatitis, an unrecognized clinical syndrome.

We developed a radioimmunoassay procedure in which we used an antibody monospecific for pancreatic acinar antigen, to sensitively and specifically test for the presence of subclinical (latent) alcoholic pancreatitis. The antigen was isolated, purified, and partially characterized. Results of testing appropriate populations of patients support the idea that chronic alcoholism is associated with chronic, subclinical damage to the pancreas and concomitant continuous release of a pancreatic acinar protein into the peripheral circulation, where it can be detected and quantitated. About 40% of the samples from chronic alcoholics (whether during a bout of acute alcoholism or during abstinence) demonstrated the circulating antigen, strongly suggesting that those alcoholics who will develop symptomatic, chronic alcoholic pancreatitis can be readily detected during the non-symptomatic stage.

Alcoholism↗
PubMed1980

Isolation and characterization of a human liver and kidney-specific protein: the hepato-renal (H-R) antigen.

This paper reports the isolation and characterization of a soluble antigen shared by the liver and kidney of human and some other animal species. Homogenates of human liver in saline were centrifugated at 27,000 g and the supernatants were fractionated by preparative polyacrylamide gel electrophoresis. The gels were divided in sections and each was injected into rabbits; after absorption with polymerized normal human serum, the antiserum obtained by injecting one of the sections reacted only with saline extracts of human liver and kidney when tested against a variety of human tissue extracts. The absorbed antiserum, polymerized and insolubilized with glutaraldehyde, was used to purify the antigen by affinity chromatography. The purified antigen proved to be a glycoprotein containing 19 percent carbohydrate, had a molecular weight of 5.8-6.0 x 10(4) Daltons and a pI of 7.2-7.4. The antigen, relatively thermostable, was precipitated by 35-55 percent ammonium sulphate; its antigenic activity was not affected by extraction with 0.6 N perchloric acid or by incubation with ribonuclease, deoxyribonuclease or neuraminidase but was destroyed by incubation with ttypsin or chymotrypsin. Immunoperoxidase studies showed that the antigen appeared concentrated in the neclei of liver and kidney glomerular epithelial and tubular epithelial cells in humans and rats. The antigen could not be detected in human hepatomas or hypernephromas or in the rat Morris hepatoma 5123.

Adenocarcinoma↗
PubMed1980

Isolation and characterization of a human pancreas-specific protein.

Homogenates of human pancreas in saline were centrifuged at 27 000 X g and the supernates were fractionated by preparative polyacrylamide gel electrophoresis. The gels were divided into sections and each section was injected into rabbits; after absorption with polymerized serum from apparently normal humans, the antiserum obtained by injecting one of the sections was tested against a variety of human tissue extracts but reacted only with saline extracts of human pancreas. The absorbed antiserum, polymerized and made insoluble with glutaraldehyde, was used to purify a pancreas-specific antigen by immunoaffinity batch technique. The purified antigen proved to be a protein with some carbohydrate content (180 mg/g by weight) and a molecular mass of about 2.25 X 10(5) daltons. The antigen is relatively thermostable, and precipitates in the range of 245.64-340.2 g/L saturated ammonium sulfate; its antigenic activity is not affected by incubation with ribonuclease or deoxyribonuclease, but is destroyed by incubation with trypsin or neuraminidase and by extraction with perchloric acid. Immunofluorescence studies show that the antigen is diffusely present in the cytoplasm of pancreatic acinar cells.

Animals↗
PubMed1980

Effect of dimethyl sulfoxide on hematopoietic stem cells in mice.

The effects of dimethyl sulfoxide (DMSO) were studied in irradiated BALB/c mice to see if DMSO has a stimulatory effect on hematopoietic stem cells. The spleen colony forming technique was employed. DMSO given after a lethal dose of radiation enhanced post-irradiation recovery and survival. The erythroid to granuloid spleen colony ratio was higher in the DMSO treated group compared to the controls. There was some evidence of an increase in the endogenous formation of erythroid colonies after DMSO treatment (0.38%). However, DMSO had no effect on exogenous erythroid colony formation; rather, it inhibited granuloid differentiation.

Animals↗
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↗