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Biomedical subjects

S Dutta

Publications and source records attributed to S Dutta.

At least 181 records · Page 10Linked to original sources
PubMed1987

Pericyte coverage is greater in the retinal than in the cerebral capillaries of the rat.

Using electron microscopic morphometry, we demonstrate here that, in the albino rat, the pericytes of the retinal microcirculation over the capillary circumference much more extensively than in five widely separate regions of cerebral cortex. The ratio of pericyte plasma membrane length in contact with the vascular circumference, to the outer circumference of the endothelial cell tube, was 0.41 +/- 0.02 (SEM) for the retinal microvessels, and ranged from 0.22 +/- 0.02 to 0.30 +/- 0.03 for the five regions of cerebral cortex. The values of this ratio for the retina differed significantly from those for the various cortical regions. Differences of comparable magnitude were obtained between ratios of pericyte to endothelial cell areas in retina and cerebral cortex. The substantial quantitative difference in pericyte coverage of the microvessel circumference between the retinal and cerebral microcirculations may have important implications for normal and pathological microcirculatory dynamics in these two organs.

Animals↗
PubMed1986

Presence of mycobacteriophage I3-like DNA sequences in the genome of its host Mycobacterium smegmatis.

The genomes of phage I3 and its host Mycobacterium smegmatis have been compared. From thermal melting studies the GC contents of DNA from mycobacteriophage I3 and its host M. smegmatis were found to be 66%. A new method, based only on the initial rates of reassociation, has been developed for calculating the DNA homology. Analysis of DNA reassociation kinetics suggested the presence of one equivalent of the phage I3 genome within the M. smegmatis genome. Southern analysis revealed the presence of almost all of the phage I3 specific sequences within the host genome.

Base Composition↗
PubMed1985

Effect of food supplementation (WIC) during pregnancy on birth weight.

Of 824 women screened, 410 were enrolled at midpregnancy in a prospective, randomized, controlled nutrition intervention study. Of these, 226 were predicted as likely to have small or large babies, 184 to have average-sized babies. Two hundred thirty eight mothers received USDA Women, Infants and Children (WIC) Food Supplementation vouchers from midpregnancy, 172 did not. Leukocyte protein synthesis (as a cell model) was significantly higher (p = 0.009) by 36 weeks gestation in supplemented mothers. Mean birth weight of their babies was greater, 3254 vs 3163 g, (+91 g) p = 0.039, adjusted for sex, gestational age, prenatal visits, pregnancy interval, smoking, and previous low birth weight infants. Controlling for entry weight obviated the significance of the difference, except for WIC supplemented smokers (greater than 10 cigarettes/day) whose babies were significantly heavier by +168 g (p = 0.017) than those of unsupplemented smokers. WIC partially protects fetal growth in smokers.

Birth Weight↗
PubMed1984

Fibre diffraction of lithium DNA shows structural variability and deviation from a regular helical structure for the B-form.

Recently, reports have appeared which show structural variations in B-DNA and indicate deviations from a uniform helical structure. We report for the first time that these indications are also present in the B-form fibre diffraction patterns for the lithium salt of natural DNA. We have used an improved method of controlling the salt concentration in the fibres. Our results are based on the appearance and disappearance of meridional reflections on different layer lines depending upon the salt.

Animals↗
PubMed1983

Effects of amino acid infusions on cell metabolism in hemodialyzed patients with uremia.

Eighteen uremic patients received i.v. infusions of a mixture of amino acids three times per week for 3 months in an effort to improve cellular amino acid imbalance and related cell bioactivities. They were a subset of 42 uremic patients stabilized by maintenance hemodialysis and were characterized by reduced cellular levels of threonine, isoleucine, methionine, and ornithine, with increased levels of aspartate, glycine, arginine, tyrosine, and phenylalanine. Protein synthesis (3H-leucine incorporation), energy level [energy charge = (ATP + 1/2 ADP)-(ATP + ADP + AMP)], and activity of the rate-limiting glycolytic enzyme pyruvate kinase were reduced in these patients compared with 32 control normal subjects. The circulating leukocyte (88 +/- 5% granulocytes) was used as a cell model. Previously, multiple regression best-subset analysis showed that a combination of the cell levels of aspartate, valine, isoleucine, ornithine, lysine, and tryptophan could "explain" 40% of the variance in protein synthesis in these patients. Similarly, a combination of the levels of aspartate, glutamic acid, glycine, ornithine, and arginine were "predictive" of the level of energy charge. We hypothesized that protein synthesis and energy level would be improved if the amino acid infusions normalized the intracellular levels of those amino acids that were predictive of the bioactivities. After 3 months of amino acid infusions, levels of the predictive intracellular amino acids were not improved, but deviated further from baseline values. Failure to detect significant improvement in the cell bioactivities is attributed to inability to correct the imbalance in the intracellular amino acid pool.

Amino Acids↗
PubMed1982

Alterations in tissue glutathione and angiotensin converting enzyme due to inhalation of diesel engine exhaust.

Quantitative changes in reduced glutathione (GSH) and angiotensin converting enzyme (ACE) of lung and extrapulmonary tissues were determined following exposure of laboratory animals to diesel engine exhaust (DEE). Exposure of male rats and guinea pigs to DEE containing 750 micrograms particulates per cubic meter for 12 wk did not cause any changes in GSH levels of lung, liver, and heart compared to control values. Rats were then exposed for various time periods to 6 mg/m3 DEE. Two weeks of exposure produced statistically significant increases of 21 and 7% in GSH levels of lung and liver, respectively, but not change in the heart. Following 4 wk of exposure, lung showed a 14% increase and heart an 11% increase in GSH level. Furthermore, rats exposed for 4 wk to DEE did not show any particular susceptibility toward the GSH-depleting effect of acetaminophen as compared to controls. A significant depletion (15%) of hepatic GSH was observed after 8 wk of exposure, while lung was still showing an increase of 18% in GSH and heart was unaffected. Time-dependent increases of 18 and 33% in serum ACE activity were noted after 4 and 8 wk of exposure. Pulmonary ACE activity did not decrease until after 8 wk, and then to a small extent (7%). The observed increases in GSH may have been related to the presence of NO2 in the DEE. On the other hand, the depletion of hepatic GSH suggests production of electrophilic compounds due to an induction of metabolic activity of liver. The change in serum ACE activity may be due to time-requiring perturbations in the pulmonary endothelial cells.

Animals↗
PubMed1982

Rate of formation of hydrogen peroxide (H2O2) in IUD-fitted human endometrium--a preliminary report.

Endometrial biopsy samples of (i) women (20-40 yr) using no contraceptive methods and (ii) women (25-45 yr) fitted with intrauterine contraceptive devices (CuT/Lippes loop) were analysed for the rate of H2O2 formation. The mean value for a normal proliferative endometrium was 10.56 +/- 1.45 nmoles H2O2 per milligram protein per 2 min, whereas the rate observed for samples of the same phase of the IUCD-fitted group without any bleeding episodes was 14.76 +/- 1.28 and that for members of the same group but who experienced excessive menstrual blood loss (menorrhagia) was 17.26 +/- 2.00, which was significantly higher than that of the control group.

Adult↗
PubMed1982

Effect of some hormones on the lactate dehydrogenase (LDH) isoenzyme patterns of Holtzman rat mammary glands.

The effect of 17 beta-estradiol, testosterone propionate and haloperidol induced prolactin release in the lactate dehydrogenase (LDH) isoenzyme patterns of female Holtzman rat mammary tissues was investigated. The LDH pattern of the mammary gland of an adult female rat showed all five isoenzymes. One week following castration, a loss of muscle type LDH-5 isoenzyme was evident in such patterns. The administration of 17 beta-estradiol alone could restore the LDH-5 isoenzyme in the mammary tissues of such castrated females. It was therefore concluded that LDH-5 isoenzyme in the mammary glands of Holtzman rats is truly estrogen dependent.

Animals↗
PubMed1981

Effect of exposure to diesel exhaust on pulmonary prostaglandin dehydrogenase (PGDH) activity.

There has been evidence that an acute exposure of laboratory animals to nitrogen dioxide (NO2) for a short period of time can cause marked inhibition of pulmonary PGDH activity. Since diesel exhaust contains NO2, this investigation was undertaken to determine the effect of long-term exposure of guinea pigs and rats to diesel exhaust. The study involves measurement of PGDH activity in the lung tissue as obtained from these animals following exposure to 250 and 1500 micrograms m-3 of diesel particles for various time periods in relation to the appropriate time-matched controls. In guinea pigs, exposure for 6 weeks to 250 micrograms m-3 of diesel exhaust seems to stimulate the PGDH activity about two-fold in comparison to the time-matched controls while, paradoxically, the exposure to 1500 micrograms m-3 of diesel exhaust did not show any particular effect. The exposures to diesel exhaust for 12 weeks, as well as 24 weeks, seem to show concentration dependent lowering of PGDH activity as compared to the time-matched controls. This study also documents the well-known species difference in PGDH activity in that the rat shows much lower activity of this enzyme than the guinea pig. Because of undetectable enzyme activity in many samples, it has not been possible to draw any meaningful conclusion as to the effect of diesel exposure on the enzyme in rat.

Aerosols↗