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Biomedical subjects

R Prasad

Publications and source records attributed to R Prasad.

At least 289 records · Page 16Linked to original sources
PubMed1985

Differences in amino acid transport and phospholipid contents during the cell cycle of Candida albicans.

Drugs like L-ethionine, 1,10-phenanthroline and 3-(2-thienyl)-DL-alanine which arrest Saccharomyces cerevisiae cells in the G1 phase, were unable to arrest Candida albicans cells. However, C. albicans could be arrested in G1 after a prolonged stationary phase. As compared to normal cells, there was a selective reduction in the level of accumulation of valine and glutamate in G1-arrested cells, while the phospholipid polar head group ratio was not significantly altered. When G1-arrested C. albicans cells were again allowed to grow, the level of different phospholipids started increasing at about the time of bud emergence (2.5 h) whereas reduced levels of accumulated valine and glutamate recovered within 1 h. The recovery of phospholipids and amino acid transport are two distinct events during the progression of C. albicans cells from G1 to S phase.

Alanine↗
PubMed1985

Immunoglobulins in certain CNS disorders: a study of CSF Ig classes G, A, M, D, and E concentrations.

Concentrations of cerebrospinal fluid (CSF) Ig classes G, A, M, D, and E have been reported in various neurologic disorders, viz, aseptic meningitis, multiple sclerosis, benign tumor, malignant tumor, and hydrocephalus. In aseptic meningitis, IgG and IgM were found to be either normal or elevated, whereas concentrations of IgA, IgD, and IgE were normal. Multiple sclerosis patients had IgG, IgA, and IgM, either normal or elevated, but IgD and IgE were on the lower end of the normal. Malignant tumor patients had elevated concentrations of IgG, IgA, IgM, and IgE, but their IgD was on the lower end of the normal. In benign tumor population IgA and IgE, and in hydrocephalus IgG and IgA, were found to be elevated in most of the patients. On statistical analysis, significant differences were observed between the means of the normal group and that of the patients' group for all the five immunoglobulins. By linear regression, a statistical relationship was observed between IgA - IgG, IgM - IgG, IgA - IgM and IgA + IgM - IgG in these neurologic disorders.

Central Nervous System Diseases↗
PubMed1985

Phospholipid enrichment of Saccharomyces cerevisiae and its effect on polyene sensitivity.

Sensitivity to polyene antibiotics, e.g., nystatin, amphotericin B, and filipin, was determined in phosphatidylcholine (PC) or phosphatidylethanolamine (PE) or phosphatidylserine (PS) enriched Saccharomyces cerevisiae cells, using glutamic acid, phenylalanine, glycine, and lysine transport as an index of polyene antibiotic action. As compared with normal cells, phospholipid-enriched cells acquired resistance towards different polyenes. However, the sensitivity of glutamic acid transport towards nystatin remained unaffected in PC-, PE-, or PS-enriched cells. In contrast to nystatin, the other two polyenes were more effective in checking the influx of amino acids. Results demonstrated that the specific enrichment of PC, PE, or PS could selectively protect S. cerevisiae cells from polyene antibiotic action.

Amino Acids↗
PubMed1985

Effect of phospholipid enrichment on nystatin action: differences in antibiotic sensitivity between in vivo and in vitro conditions.

Polyene-nystatin had a selective effect on the transport of glutamic acid and lysine in phosphatidylcholine-, or phosphatidylethanolamine-enriched cells of Saccharomyces cerevisiae. However, liposomes prepared from lipid extracts from the same cells did not mimic the results of in vivo studies. Our in vitro results demonstrated that factors other than sterols, e.g. phospholipid enrichment, protein lipid interactions and lipid bilayer asymmetry may also affect the overall susceptibility of polyene antibiotics.

Biological Transport↗
PubMed1985

Effect of protein calorie malnutrition and calcium deficiency on hepatic iso-metallothioneins in Cd-exposed monkeys.

Oral administration of cadmium results in the induction of metallothionein in liver of rhesus monkeys subjected to protein calorie malnutrition and calcium deficiency. Metallothionein was resolved into three iso-proteins viz. MTa, MTb & MTc which varied in their quantities and metal composition in these nutritional stress conditions. 'MTc' was the major iso-protein in protein calorie malnourished monkeys, while 'MTb' predominated in the calcium deficient group.

Animals↗
PubMed1985

Albendazole in the treatment of intestinal helminthiasis in children.

One hundred sixteen children between 2 and 15 years of age entered a clinical trial of albendazole after examination of their stools revealed ova of one or more intestinal helminths. The drug was administered as a single 400-mg dose (20 ml of 2% suspension) to all the patients except those having Hymenolepis nana infection, who received treatment for three consecutive days. The stools were reexamined on days 7 and 14 posttreatment and after three months for Taenia infections. Patients were considered cured if all parasitological examinations of the feces were negative after treatment. After a single oral dose, albendazole was highly effective in ascariasis (91.9%), ancylostomiasis caused by Ancylostoma duodenale (87.2%), and H nana infection (71.4%). The drug was well tolerated, and no abnormalities were observed in hematological or blood chemistry values. Since the drug is safe and effective as a single-dose treatment of common helminthic infections, it should be considered for mass therapy in the community.

Adolescent↗
PubMed1984

Subdivision of S-phase and its use for comparative purposes in cultured human cells.

Intranuclear DNA synthesis and concomitant chromosome duplication occur during a discrete period of the cell cycle termed S-phase. Using replication-banding and serial time sampling in asynchronous cell populations, it is possible to subdivide the S-phase into four or five chronological compartments termed "subphases". This paper discusses methods for analysing the sampling data to obtain the average duration of these subphases and the positions within S of the borders between them. Such information not only allows a more detailed analysis of the cell cycle, but also provides parameters which can be used for rigorous comparisons of cell populations from different sources and experimental conditions. Examples are given of application of the method to normal and chromosomally abnormal primary human fibroblasts and lymphocytes growing in short-term in vitro culture.

Bromodeoxyuridine↗
PubMed1984

Glyoxalase-I activity and cell cycle regulation in yeast.

The status of glyoxalase-I was explored in exponentially growing and G1 arrested temperature sensitive (ts) cell division cycle (cdc) mutants of Saccharomyces cerevisiae. It was observed that the specific activity of this enzyme was correlated with overall growth status. The activity was high in actively growing cells and was low in G1 arrested cells. Specific activities of glyoxalase-I were also low in G1 arrested prolonged stationary phase (PSP) cells of S. cerevisiae and Candida albicans. The activity of glyoxalase-I recovered when G1 arrested S. cerevisiae (ts) cells were allowed to regrow under permissive conditions. Results demonstrate that although glyoxalase-I activity is a good indicator of cell growth status, it is not involved in cell cycle regulation of this eukaryotic organism.

Candida albicans↗
PubMed1984

Coupling between phosphatidylinositol metabolism and cdc 28 gene product of Saccharomyces cerevisiae. On the possible mechanism of cdc 28 gene action.

It was shown that the decrease in phosphatidylinositol (PI) content in cdc 28 G1-cells was due to a defect in inositol transport. This decrease in inositol transport was linked to microtubular function which was evident by the effect of a microtubular disrupting agent (colcemid) on inositol transport in stationary phase A364A cells. The involvement of PI in yeast G1 phase was further substantiated by the observation that o-phenanthroline, which blocks yeast cells in G1 phase, could inhibit inositol transport and PI levels as well. It is proposed that the regulation of PI metabolism is mediated by the gene cdc 28 and that microtubules may play a major role in the mechanism of action of this gene product.

Demecolcine↗
PubMed1984

Effect of dietary chronic cadmium exposure on cell-mediated immune response in rhesus monkeys (Macaca mulatta): role of calcium deficiency.

The role of Ca deficiency on the immunomodulatory effects of chronic Cd exposure for a period of 10 weeks in male Rhesus monkeys were assessed by the blastogenic capacity of peripheral blood lymphocytes (PBL) in response to T-cell mitogens, phytohemagglutinin (PHA), and concanavalin A (Con A). Calcium deficiency significantly decreased the blastogenic response to PHA (P less than 0.01) and Con A (P less than 0.05). Although Cd exposure in normal monkeys significantly increased the blastogenic response to Con A (P less than 0.05), Cd exposure in Ca-deficient monkeys produced a further significant decrease in the blastogenic response to Con A (P less than 0.001). Total and ionic Ca were also significantly decreased in plasma of Ca deficient monkeys exposed to Cd. It is possible that these two observations may be related to each other. Thus, it is important to assess the nutritional status of the host while evaluating the immunotoxicological effects of an environmental pollutant.

Animals↗
PubMed1984

Study of duodenal ulcer disease in 100 families using total serum pepsinogen as a genetic marker.

Although various markers have been used in attempts to elucidate the mode of inheritance of duodenal ulcer, they have not significantly contributed to a clear understanding of the problem. In the present study total serum pepsinogen was used as a genetic marker and its concentrations were estimated in 100 ulcer patients and their family members up to three generations. Eighty three per cent of the ulcer patients had hyperpepsinogenaemia on a familial basis, and it followed an autosomal dominant mode of inheritance. Thus a large majority of ulcer patients have associated hyperpepsinogenaemia which forms a genetic basis of their disease. The remaining 17% ulcer patients did not have associated hyperpepsinogenaemia nor was the ulcer inherited by the family. Based on these observations we wish to suggest that duodenal ulcer associated with hyperpepsinogenaemia may be considered a genetic disease. This type may be termed 'primary duodenal ulcer'. In the remaining patients without hyperpepsinogenaemia or affected relatives the ulcer may be called 'secondary duodenal ulcer'. Thus total serum pepsinogen may be considered a reliable genetic marker in helping to delineate the genetic disorder from the non-genetic, thereby improving the predictive ability in duodenal ulcer.

Adolescent↗
PubMed1984

Cytological subdivision of the S phase of human cells in asynchronous culture.

A method is described for subdividing S phase cells in asynchronous cell cultures on the basis of replication band patterns produced in chromosomes by bromodeoxyuridine incorporation. The criteria used for cell classification are objective, requiring the presence or absence of specific bands on particular chromosomes, and therefore lead to subdivisions amenable to quantitative analysis and for comparative purposes. Two schemes are given: key 1, based on bands in chromosomes 2 and 5, leads to five sub-phases; and key 4, based on bands in chromosomes 3 and 4, leads to four sub-phases. The order of the sub-phases, though not their relative durations, is identical in the six primary cell cultures (four fibroblast and two lymphocyte) tested. The technique provides for a detailed study of the programme of chromosome replication in normal and abnormal cells which, in time, should produce new criteria for diagnostic purposes.

Adult↗
PubMed1984

Tissue proteins in breast cancer, as studied by use of two-dimensional electrophoresis.

Proteins from 25 specimens of malignant breast tissue were separated by "high-resolution" two-dimensional gel electrophoresis. The number of polypeptide spots detectable in individual gels varied from 259 to 471 (mean 347; SD 68) per milligram of wet tissue. Many polypeptide spots were not consistently present in all malignant tissues. Ten different in vivo polypeptides, observed neither in five non-malignant breast tissues nor in human milk, were present in more than 22 of the 25 cases of breast tumor tissues examined. Five of these polypeptides appeared to be identical to five in vitro polypeptides found in separations from cultured human ductal carcinoma cells. Further studies are required to verify the specificity of these tumor-associated proteins before they can be considered for breast tumor-specific in vitro diagnostic testing or targeting in selective in vivo anti-cancer therapy.

Adult↗