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Biomedical subjects

S Sen Gupta

Publications and source records attributed to S Sen Gupta.

12 recordsLinked to original sources
PubMed1995

A purine permease in Candida glabrata.

Competition experiments revealed that adenine and guanine were transported by a purine permease in both Candida glabrata 4 and a C. glabrata 4 cytosine permease negative mutant. The C. glabrata 4 cytosine permease negative mutant was isolated using 5-fluorocytosine selection. This mutant no longer transported cytosine, but transported adenine and guanine. A transport system for hypoxanthine was not detected. Hence, in addition to the cytosine permease, a purine permease exists in C. glabrata. This differs from the purine cytosine permeases in Saccharomyces cerevisiae and Candida albicans which transport adenine, cytosine, guanine and hypoxanthine.

Adenine↗
PubMed1992

Are insomniacs sleepy during the day? A pupillometric assessment.

A biodevelopmental model of insomnia is articulated specifying coordinated nighttime (disturbed sleep pattern) and daytime (no excessive daytime sleepiness) characteristics defining an insomnoid classification in at-risk groups: short sleepers and older adults. Pupillometry is proposed as a useful means of discriminating degree of daytime sleepiness to aid in the differential diagnosis of insomnia and insomnoid states, and the present study tested the discriminative validity of this approach. Noninsomniac (n = 34) and insomniac (n = 29) college students submitted to four 10 min pupillometry sessions tracking daytime sleepiness from morning arising to bedtime. Pupil diameter proved to be an able discriminator of these two groups though substantial overlap of the two distributions was also noted. The results supported the sensitivity of pupillometry in detecting daytime sleepiness, but yielded alternative interpretations. We observed statistical differentiation in insomniac and noninsomniac daytime sleepiness, but substantial, functional overlap between these groups. Assessment and treatment implications arising from the biodevelopmental model were hypothesized.

Adolescent↗
PubMed1991

Glucose oxidase immobilized electrode for potentiometric estimation of glucose.

Glucose oxidase has been immobilized onto a thin platinum strip, by co-crosslinking with bovine serum albumin and glutaraldehyde. The retention of redox characteristics of glucose oxidase has been verified by cyclic voltammetry. The activity of the immobilized enzyme reduces to a quarter of its value when the enzyme is in solution but improves when coimmobilized with 1 M urea. The potentiometric response builds up and remains stable after 100 s. It is sensitive to the thickness of the immobilizing matrix. pH and temperature. An improvement in the performance of the electrode has been achieved by co-immobilizing 2 M urea and metal ions such as Mg2+ and Mn2+. The presence of Cu has been proved to be detrimental. The electrode has been calibrated in the 0.1-5.0 mM glucose concentration range. It gives a stable response for more than 50 independent assays and can be stored for 60 days without significant loss of function.

Biosensing Techniques↗
PubMed1988

Induction of repair functions by hydrogen peroxide in Chinese hamster cells.

Hydrogen peroxide has been found to kill Chinese hamster V79 cells as an exponential function of dose. When a small dose (0.9 microgram/ml for 1 h) was used as a pretreatment, before exposure to higher concentrations of the same agent, the cells became more resistant to killing than those which were not so pretreated. The presence of cycloheximide or benzamide, during this pretreatment, inhibited this observed increase in resistance. This pretreatment also resulted in decreased killing efficiency by MNNG and gamma-rays, but had no effect upon UV-light-induced killing. The results suggest that proteins (repair enzymes?) are synthesized after treatment with the small dose of hydrogen peroxide, and that these induced proteins enhance the cellular repair functions for agents causing DNA breaks.

Animals↗
PubMed1987

Significance of eosinophil and mast cell counts in rectal mucosa in ulcerative colitis. A prospective controlled study.

Eosinophil and mast cell counts were done in 44 patients with active ulcerative colitis, 10 patients with ulcerative colitis in remission, and 44 matched subjects with functional bowel disorder. Mean (+/- SD) rectal eosinophil counts (EC) per unit area were significantly high (P less than 0.01) in active ulcerative colitis (5.80 +/- 5.49) as compared with inactive disease (2.81 +/- 2.19) or controls (3.01 +/- 1.67). Eosinophil count was not significantly different in the acute stage between responder (6.36 +/- 5.95) and nonresponders (5.1 +/- 5.84) to medical treatment and was thus of little discriminatory and prognostic value. Mean (+/- SD) EC was reduced from 6.36 +/- 5.95 to 3.91 +/- 3.19 in responders after four weeks of medical treatment. There was little change in the EC with treatment in nonresponders. No correlation was seen between tissue eosinophils and clinical severity of ulcerative colitis. Mast cell count was not significantly different between patients with active ulcerative colitis, inactive disease, and controls and thus had little diagnostic or prognostic value. It can be concluded therefore, that EC in the rectal mucosa indicated activity but not severity of ulcerative colitis. A reduction in EC possibly indicated remission. Rectal EC, however, cannot correctly prognosticate the treatment response and outcome of the disease.

Adult↗
PubMed1978

Incompatible reactions between some plants and pathogenic bacteria.

Incompatible combinations of plant and plant bacteria produce an incompatible reaction at different rates, producing, besides the typical hypersensitive reaction, also darkening, yellowing, and fading. Plants differ in their responsiveness to plant bacteria in terms of reaction rate. Study of incompatible reactions may differentiate the species and strains of plant bacteria if properly explored.

Bacillus↗