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Biomedical subjects

R Rai

Publications and source records attributed to R Rai.

124 records · Page 7Linked to original sources
PubMed1989

Coagulation abnormalities in systemic lupus erythematosus.

Coagulation profile was studied in 55 patients of systemic lupus erythematosus (SLE). Abnormal kaolin clotting time (KCT) was observed in fewer patients (12.9%) as compared to abnormal Russel's viper venom time (RVVT, 20.4%) or activated partial thromboplastin time (APTT, 32.7%). Prolonged prothrombin time (PT), observed in 7.3 per cent patients was not found to be a sensitive test for lupus anticoagulant (LAC). The correction of RVVT and KCT on addition of inosithin suggested a deficiency of platelet lipid factor in these patients. The initial value of uncorrected KCT in patient's plasma did not correlate with the amount of inosithin required for neutralisation. Occurrence of thromboembolic events was significantly associated with prolonged KCT. No other clinical feature showed significant association with any coagulation abnormality.

Adolescent↗
PubMed1988

Structure and transcription of the allantoate permease gene (DAL5) from Saccharomyces cerevisiae.

We determined the nucleotide sequence of the DAL5 gene, which encodes a component of the allantoate transport system. Translation of the sequence revealed that the DAL5 gene product is highly hydrophobic. It possesses an alternating motif of hydrophilic sequences that can potentially be folded into alpha-helices and hydrophobic sequences that can potentially be folded into beta-pleated sheets. These are expected characteristics of an integral membrane protein, which correlate well with DAL5 gene function. S1 protection fragments generated by DAL5 transcripts exhibited high heterogeneity over a 30-base-pair range. This pattern of fragments was not affected by growth conditions of the cells or the conditions of the assay.

Allantoin↗
PubMed1987

Regulation of allantoate transport in wild-type and mutant strains of Saccharomyces cerevisiae.

Accumulation of intracellular allantoin and allantoate is mediated by two distinct active transport systems in Saccharomyces cerevisiae. Allantoin transport (DAL4 gene) is inducible, while allantoate uptake is constitutive (it occurs at full levels in the absence of any allantoate-related compounds from the culture medium). Both systems appear to be sensitive to nitrogen catabolite repression, feedback inhibition, and trans-inhibition. Mutants (dal5) that lack allantoate transport have been isolated. These strains also exhibit a 60% loss of allantoin transport capability. Conversely, dal4 mutants previously described are unable to transport allantoin and exhibit a 50% loss of allantoate transport. We interpret the pleiotropic behavior of the dal4 and dal5 mutations as deriving from a functional interaction between elements of the two transport systems.

Allantoin↗
PubMed1987

Transcriptional regulation of the DAL5 gene in Saccharomyces cerevisiae.

We demonstrate that the DAL5 gene, encoding a necessary component of the allantoate transport system, is constitutively expressed in Saccharomyces cerevisiae. Its relatively high basal level of expression did not increase further upon addition of allantoin pathway intermediates. However, steady-state DAL5 mRNA levels dropped precipitously when a repressive nitrogen source was provided. These control characteristics of DAL5 expression make this gene a good model with which to unravel the mechanism of nitrogen catabolite repression. Its particular advantage relative to other potentially useful genes derives from its lack of control by induction and hence the complicating effects of inducer exclusion.

Allantoin↗
PubMed1982

A bifunctional gene product involved in two phases of the yeast cell cycle.

The cell cycle in Saccharomyces cerevisiae is divided into two distinct phases. Unbudded, mononucleate cells in the G1 phase can react to relevant environmental changes by mating, sporulating, or by entering stationary phase. DNA synthesis and bud initiation occur almost simultaneously and mark 'commitment' to the completion of mitosis. Temperature-sensitive mutations at the cdc28 locus are known to cause arrest in the G1 phase of the cell cycle at the restrictive temperature. Here we show that the cdc28 gene product is also active in post-G1 cell cycle functions, and that a different property of the gene product may be required for each phase of the cycle in which it acts.

Cell Cycle↗
PubMedDate not supplied

GABA transport in Saccharomyces cerevisiae.

Gamma-aminobutyrate (GABA) accumulation in growing cultures of Saccharomyces cerevisiae was shown to occur by means of an active transport system that is inhibited by proton ionophores, azide, fluoride and arsenate ions. Transport occurred maximally at pH 5.0 and exhibited apparent Km values of 12 microM and 0.1 mM. Accumulated GABA did not efflux upon treatment with proton ionophores and exchanged with extracellular material only very slowly. However, release was complete upon treatment with nystatin. These observations raise the possibility that a major portion of intracellular GABA is sequestered in the vacuole. The response of GABA uptake to growth on various nitrogen sources suggested that uptake may be subject to several types of regulation.

Biological Transport, Active↗
PubMedDate not supplied

Bilateral en coup de sabre-a rare entity.

Linear scleroderma involving the frontal or frontoparietal region of the scalp (with or without associated facial hemiatrophy) is called "en coup de sabre" (like the stroke of a sabre). We report a case which to the best of our knowledge is only the fifth instance of this subset of localized morphea occurring in a bilateral distribution. We believe that the rarity of this presentation warrants a report.

Child, Preschool↗
PubMedDate not supplied

Circadian periodicity of plasma lipid peroxides and other anti-oxidants as putative markers in gynecological malignancies.

BACKGROUND: The chronome (from chronos, time, and nomos, rule), or time structure, of lipid peroxidation and anti-oxidant defense mechanisms may relate to prevention and curative chronochemotherapeutic efficacy and management. PATIENTS AND METHODS: Newly diagnosed women with gynecological malignancies (N = 30), 30-60 years of age, and age-matched clinically healthy women (N = 35) provided blood samples every 6 hours for 24 hours under standardized conditions. Plasma malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities, and serum ascorbate, urate and high-density lipoprotein cholesterol (HDL-C) concentrations were determined. RESULTS: Each variable underwent circadian variation (p < or = 0.002). Patients differed from controls by their overall chronome-adjusted mean value (MESOR) and by the circadian dynamics in the spectral element of their chronome. CONCLUSION: Chronomes of putative anti- and pro-oxidants should be mapped to explore their putative chemotherapeutic role as markers in cancer chronoprevention and management of established disease.

Adult↗