Search PubMed⌕ Search

Biomedical subjects

S Dutta

Publications and source records attributed to S Dutta.

At least 163 records · Page 9Linked to original sources
PubMed1992

Modulatory influences of estrogen and progesterone on cervical dysplasia in mice model system.

The effectiveness of estrogen and progesterone on the different types of cervical dysplasia are poorly documented compared to their effects on the total process of cervical carcinogenesis. In the present study, an attempt has been made to evaluate the influences of estrogen and progesterone on the different types of cervical dysplasia which are believed to be the antecedents of cervical carcinoma induced by chemical carcinogen (20-Methy cholanthrene) in the mice model system. It was observed that moderate dysplasia is less aberrant than that of marked dysplasia which could not be modified by either of the hormones.

Animals↗
PubMed1991

Electromechanical effects of menadione on isolated rat heart in relation to oxidative stress.

Although Ca2+ overloading has been observed in hepatocytes and in the isolated liver treated with 0.2 mM menadione, it has not been determined if menadione has similar effects on cardiac tissue and, if so, whether Ca2+ overloading leads to cardiac contracture, and if such an event results from plasma membrane peroxidation initiated by oxidative stress. The present study reveals that when the isolated heart is perfused with 0.2 mM menadione for 30 min, it shows Ca2+ overloading, which can not be reversed even after 30 min of drug-free perfusion. The time courses of glutathione, ethane, and LDH release from the hearts do not show a parallel pattern of abnormality between 30 and 60 min, indicating that contractile failure precedes the development of lipid peroxidation or plasma membrane disintegration. The evidence that the plasma membrane of menadione-treated rat cardiac tissue remains intact is supported by the observation that the resting membrane potential of the atrium remains virtually unchanged during the 30 min of drug exposure and then gradually falls (-67 +/- 3.1 vs. -76 +/- 2 mv) only during the last 10 min of the drug washout. Interestingly, even after the atria are treated with menadione for 30 min and followed by washout of 30 min, and have shown calcium overloading, as evidenced by contracture, they are still capable of generating action potentials in response to electrical field stimulation.

Animals↗
PubMed1991

Antibodies to streptococcal opacity factor in a selected Indian population.

Antibody to at least one type of streptococcal opacity factor (OF) was present in 39.0% of 235 selected subjects and, in 47.8% of these, to more than one type. Only 21.6% of children less than 4 years old had antibody to OF; these were to one type in 62.5% or to more than one in 37.5%. In the study group as a whole, the commonest antibodies were those to OF from M-serotype 25 followed, in descending order, by serotypes 4, 22, 2, 9, 48, 49, 28, 61 and 75. Patients with rheumatic fever or rheumatic heart disease most often had antibodies to OF from M-types 25, 22, 4 and 9, whereas in patients with acute glomerulonephritis, antibodies to OF from M-types 48, 49 and 61 were commonest. The limitations of the OF-inhibition test as an epidemiological marker for prevalent M-types of group A streptococci are discussed.

Adolescent↗
PubMed1991

Modulation of cervical carcinogenesis by tamoxifen in a mouse model system.

Insertion of cotton thread impregnated with beeswax and 20-methylcholanthrene (carcinogen) inside the canal of the uterine cervix in intact and oophorectomized mice results in the expression of dysplasia and carcinoma of the cervical epithelium. Based upon the experimental cervical carcinogenesis observed in this mouse model system, the present study shows distinctly the modulatory effect of tamoxifen on the incidence of cervical carcinoma. Besides this, tamoxifen significantly lengthens the latent period for both dysplasia and carcinoma in the cervical epithelium. This manifestation was found more marked in oophorectomized animals.

Animals↗
PubMed1991

Observation on serum prolactin in hepatic cirrhosis.

Serum prolactin assays in patients of hepatic cirrhosis were analysed. Patients with cirrhosis had higher values of serum prolactin (27.2 +/- 5.1 ng/ml in males and 38.4 +/- 4.1 ng/ml in females) as compared to control subjects (p less than 0.05). Majority of patients of cirrhosis with suspected portal-systemic encephalopathy had significantly higher serum prolactin than those without encephalopathy (p less than 0.05). Significantly higher values of serum prolactin on admission had positive correlation with mortality (p less than 0.01). Clinico-biochemical severity of hepatic dysfunction was directly correlated with level of serum prolactin. The present study reveals the possibility of diagnostic and prognostic values of serum prolactin in cirrhosis, specially in clinical/sub-clinical subsets of portal-systemic encephalopathy.

Biomarkers↗
PubMed1991

Application of serum opacity factor in subtyping of group A streptococci & identification of new M-types.

Out of 742 isolates of group A streptococci (GAS), 34.0 per cent were positive for production of serum opacity factor (SOF). The T and M typability of these GAS strains was 93.3 and 10.8 per cent respectively. Clustering of the strains under the T patterns 5/12/27, 8/25/Imp. 19 and 3/13/B3264 and low M typability indicated the utility of SOF testing as an additional marker in epidemiological characterisation of GAS. SOF was further found to be useful in identification of new M type and simplified M typing by saving time, labour and sera.

Antigens, Bacterial↗
PubMed1990

A study of ozone-induced edema in the isolated rat lung in relation to arachidonic acid metabolism, mixed-function oxidases and angiotensin converting enzyme activities.

In order to elucidate the role of arachidonic acid in the pathogenesis of ozone-induced pulmonary edema, isolated rat lungs were exposed to 14C-arachidonic acid in the presence or absence of ozone and the incorporation of radiolabelled arachidonate into pulmonary cell lipids was studied. The perfusates from these studies were also subjected to differential extraction and thin layer chromatography (t.l.c.) to determine synthesis of both cyclo-oxygenase and lipoxygenase products. In the presence of an edemagenic concentration of ozone, isolated lungs incorporated significantly less exogenous arachidonic acid into phosphatidyl choline and phosphatidyl ethanolamine, whereas incorporation into phosphatidyl inositol or serine was not affected. The edemagenic concentration of ozone also increased production of a variety of arachidonic acid metabolites via cyclo-oxygenase and lipoxygenase pathways. In separate studies, a similar ozone exposure did not affect 14CO2 production, resulting from the metabolism of 14C-antipyrine by mixed function oxidases (MFO). Similarly, an edemagenic concentration of ozone did not affect pulmonary angiotensin converting enzyme activity (ACE) as determined by the rate of formation of 14C-hippuric acid from 14C-hippuryl-histidyl-leucine (14C-HHL). Thus, acute ozone exposure is specifically associated with a reduced incorporation of arachidonate into phospholipids and with an increased conversion of arachidonate into bio-active metabolites.

Animals↗
PubMed1990

Differences in levels of neuroglial cell death in jimpy male mice and carrier females.

Jimpy (jp) is an X-linked disorder which results in a variety of glial cell abnormalities and the virtual absence of myelin in the central nervous system (CNS) of affected males. Female heterozygote carriers of the jp gene are mosaics. The wild-type genome will be expressed in roughly half of their cells, while in the other half the jp genome will be expressed. We have exploited this characteristic in order to determine whether the premature oligodendroglial death previously described in jp males is a primary effect of the mutation. Mosaic spinal cords were examined at the light-microscopic level for the presence of pyknotic cells at ages when oligodendroglial death is quite pronounced in jp males. The percentage of pyknotic glial cells (less than 0.6%) is not statistically different in normal and mosaic females at 5 and 30 days. At 14-15 days there is a slight increase in mosaic cords (1.2 vs. 0.75%) but there are still 10 times more dying glia in jp male cords of the same age. The low level of oligodendroglial death in mosaic spinal cords suggests that it is secondary to some other jp abnormality. Small increases in glial death over a protracted period of time could result in lower numbers of oligodendrocytes in older mosaics. Even if this occurs, the data still support the idea that the phenotype of genetically jp cells can be favorably altered by the mosaic environment.

Animals↗
PubMed1989

Electroconvulsive therapy in neuroleptic-induced parkinsonism.

The effect of electroconvulsive therapy (ECT) on the severity of neuroleptic-induced parkinsonism was studied in nine schizophrenic inpatients in a longitudinal triphasic design: neuroleptics-neuroleptics plus ECT-neuroleptics. The results suggest that ECT has a true antiparkinsonian potential. The role of ECT in the treatment of Parkinson's disease, especially with therapy-resistant patients complicated with on-off symptoms, is highlighted.

Adolescent↗
PubMed1989

Comparative toxicology of ozone and t-butyl hydroperoxide on isolated rat lung.

Comparative studies were undertaken on the effects of ozone and t-butyl hydroperoxide (t-BuOOH) on alkane production, glutathione and lactate dehydrogenase (LDH) release from isolated rat lungs. Specifically, ethane and pentane production, as well as glutathione and LDH release were simultaneously determined at different time intervals from the isolated lung preparation in the absence and presence of toxic concentrations of ozone or t-BuOOH. When compared to control conditions, both toxic agents produced a marked decrease in the dry weight to wet weight ratios, reflecting the development of acute pulmonary edema. These toxic agents also caused a marked increase in the efflux of glutathione into the effluent. A much higher glutathione efflux into the effluent was observed during t-BuOOH perfusion in comparison to ozone exposure. In parallel with the enhancement of glutathione release a significant increase in ethane production was also observed during t-BuOOH perfusion. However, the production of either alkane by ozone inhalation was not significantly different from that in the control conditions. Unlike glutathione release, there was no marked increase of LDH release into the effluent following exposure to t-BuOOH or ozone. This suggests that the observed increase in glutathione release caused by t-BuOOH or ozone treatment was not associated with non-specific destruction of cell membrane integrity.

Air↗
PubMed1988

Alkane production by isolated rat heart and lung.

Ethane and pentane have been measured as an index of lipid peroxidation occurring in the isolated perfused rat heart as well as lung preparations. In order to initiate lipid peroxidation cumene hydroperoxide was infused. The results show a significant enhancement of both ethane and pentane evolution from both isolated organs by cumene hydroperoxide. The production of alkanes by perfusion of high doses of cumene hydroperoxide in lungs is about one-half that of the isolated heart. Such reduced production of alkanes by the lungs can be explained by the fact that lung lipids, which contain mostly saturated fatty acids, might have resisted the peroxidative degradation. In comparison to cumene hydroperoxide, tert-butyl hydroperoxide also increased alkane production, caused a reduction of glutathione content and increased oxidized glutathione in hearts. 4-Hydroxynonenal infusion was much less effective in causing alkane release but caused profound depletion of cardiac glutathione. Paraquat had relatively insignificant effects on cardiac lipid peroxidation and glutathione content.

Animals↗
PubMed1987

Comparison of effects of ozone, cadmium chloride and carbon tetrachloride on [14C]antipyrine metabolism in conscious rats.

Previously, Graham et al. found evidence that pentobarbital-induced sleeping time was enhanced in various animals following exposure to 1 ppm of ozone in air. The present study was undertaken to investigate whether similar ozone exposure would cause inhibition of metabolism of another model drug, [14C]antipyrine, in conscious rats. Furthermore, this study also investigated whether, like that of ozone, other lipid-peroxidizing agents such as cadmium and carbon tetrachloride would affect metabolism of [14C]antipyrine in conscious rats. The results showed no significant effect of ozone exposure on subsequent metabolism of [14C]antipyrine in conscious rats as revealed by very similar 14CO2 exhalation rate (CER)-time profiles before and after ozone treatment under various exposure protocols. Even though the exposure to ozone caused no inhibition of antipyrine metabolism in conscious rats, cadmium and carbon tetrachloride, on the other hand, markedly inhibited metabolism of this model drug. In agreement with the reported sex-difference in toxic effects of cadmium, during the present study the cadmium-induced inhibitory effect on the CER-time profiles was observed in male but not in female rats. In contrast, no clear sex-dependency was noted in the inhibitory effect of carbon tetrachloride on [14C]antipyrine metabolism.

Animals↗
PubMed1987

Cerebral cortical capillary basement membrane thickening in galactosaemic rats.

Wistar-Kyoto rats fed a diet containing 30% by weight galactose for 15-21 months developed significant thickening of the endothelial basement membranes of capillaries from the frontal cortex of the cerebrum, by comparison with cerebral capillary basement membranes from animals on a standard diet (p less than 0.001), or animals receiving a diet containing 30% galactose together with 250 mg/kg diet of the aldose reductase inhibitor, Sorbinil (0.001 less than p less than 0.01). The effect was similar to that which we have reported previously in the retinal capillaries of these animals. Spontaneously hypertensive rats on the high-galactose diet showed modest cerebral capillary basement membrane thickening (0.02 less than p less than 0.05) only for one of the measurement protocols utilised, and the process was not prevented by Sorbinil. Biochemical assays of retina, cerebral cortex, and blood serum from Wistar-Kyoto and spontaneously hypertensive rats maintained on the Sorbinil regimen showed that the drug did cross the blood-retinal and blood-brain barriers. Similar to our previous study on the retinal capillaries, we observed no degeneration of pericyte or endothelial cell cytoplasm, and no alteration in the pericyte/endothelial cell nuclear ratio in the cerebral capillaries of galactosaemic animals, by comparison with controls. Based on immunocytochemical studies in the human retina, it has been claimed that aldose reductase is present in capillary pericytes but absent in the endothelial cells. However, we observe a considerably smaller pericyte/endothelial cell nuclear ratio in the capillaries of the cerebral cortex of the rat, by comparison with those of the retina.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗