Biomedical subjects
Publications and source records attributed to R C Sharma.
Reactive perforating collagenosis is characterised by trans-epidermal elimination of collagen and is hypothesized to be both autosomally dominant and recessive. We report a family in which two brothers and a sister had lesions of reactive perforating collagenosis.
This paper presents the results of in vivo measurements on a worker from a fuel reprocessing plant who was involved in an actinide intake. The results revealed that false indications of an actinide lung burden could arise from a contaminant present elsewhere in the chest region. Consequently, it is important that lung monitoring programs for occupational workers handling actinides are conducted with this caution in mind and that due consideration is given even in cases of minor cuts/wounds in order to rule out substantial overestimation of internal radiation doses.
A 28-year-old married female developed histoid papules and nodules de novo over her face, extremities, back, buttocks and thighs. She had developed erythema nodosum leprosum lesions without any antileprosy treatment. Histopathology from a histoid nodule showed well defined nodular collections of plump, spindle-shaped histiocytes. A few globi were also seen with Ziehl Neelson staining. Leucocytoclastic vasculitis was present in the ENL lesion. The CD4:CD8 ratio was 1.5:1.
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Orissa is known for its contribution of 15-20% of malaria cases to the national total. Deaths due to malaria in the state are also not uncommon. Proportion of P. falciparum cases have reached to 85%. In the recent years over 0.3 million confirmed malaria cases have been reported each year. Annual consumption of chloroquine in the state is over 170 lakh tablets. A 17 year study on monitoring of choloroquine resistance in P. falciparum in Orissa revealed that out of a total of 1165 tests conducted in vivo, in 12% of the cases RI level of resistance was detected. And 4.4% cases were of RII and 1.9% RIII level. 51% of the sample tested in vitro showed P. falciparum resistance to chloroquine. P. falciparum resistance to chloroquine appears to have been developed by the parasite over the length and breadth of the state. Strengthening of the monitoring of drug resistance in P. falciparum in the state is indicated.
Research studies conducted so far have had little bearing on the National Malaria Eradication Programme implementation for want of operational component. In India there is no dearth of scientific knowledge and technical know-how but dearth of operational research of direct relevance to the programme. The rationale for research under the operational conditions of the NMEP is discussed in this paper.
P-glycoprotein (Pgp), a transmembrane efflux pump encoded by the MDR1 gene, transports various lipophilic drugs that enter the cell by passive diffusion through the lipid bilayer. Pgp-expressing multidrug-resistant cell lines are not usually cross-resistant to a hydrophilic antifolate methotrexate (MTX). MTX enters cells primarily through a folate carrier, but passive diffusion becomes the primary mode of MTX uptake in carrier-deficient cells. To test if a deficiency in MTX carrier would allow Pgp to confer resistance to MTX, a MTX carrier-deficient cell line (3T6-C26) was infected with a recombinant retrovirus expressing the human MDR1 gene. The infected 3T6-C26 cells showed increased survival in MTX relative to uninfected cells. Multistep selection of the infected cells with vinblastine led to increased Pgp expression and a concomitant increase in resistance to MTX. MTX resistance of Pgp-expressing 3T6-C26 cells was reduced by Pgp inhibitors, including a Pgp-specific monoclonal antibody UTC2. In contrast, the expression and the inhibition of Pgp had no effect on MTX resistance in 3T6 cells with normal carrier-mediated MTX uptake. Thus, a deficiency in the MTX carrier enables Pgp to confer resistance to MTX, suggesting that hydrophilic compounds may become Pgp substrates when such compounds enter cells by passive diffusion.
UNLABELLED: The emerging concept that various fat compartments are metabolically active and play separate and decisive roles in the pathogenesis of coronary atherosclerosis, hypertension, insulin resistance, diabetes and stroke, has given obesity research a new direction. Of particular interest is the relative amount of intra-abdominal fat thought to be responsible for the metabolic complications. We studied the precise fat distribution and its correlations with the metabolic parameters in 44 non-human primates (Macaca fascicularis). Intra-abdominal, subcutaneous, and total abdominal fat (IAF, SAF, TAF) were assessed by magnetic resonance imaging (MRI) and somatometry. Quantitative computer analyses of abdominal MRI scans revealed predominant IAF distribution. Box plot analysis of IAF and SAF revealed wide diversity in the amounts of fat, especially in monkeys with body mass index (BMI) < 30 kg/m2. Primates with similar BMI in each quartile revealed an extensive heterogeneity in IAF as well as SAF. Numerous significant correlations within site-specific somatometric measurements as well as within the MRI determinants of abdominal fat were seen. However, only body weight correlated with IAF and skinfolds could predict SAF. After adjusting for body weight, partial correlation analysis showed a significant correlation (P < 0.05) between total cholesterol and IAF. CONCLUSION: MRI revealed considerable heterogeneity of IAF, SAF and TAF in cohort of primates believed to be homogeneous by somatometric definition. Male cynomolgus monkeys appear to be a valuable model for a systematic evaluation of fat. Individuals with identical body weight and height may show a diverse pattern of fat distribution.
Oxy-free radicals may be involved in the pathogenesis of accelerated atherosclerosis in hypertension. We evaluated the direct antioxidant potential of probucol in hypertensive arteries by studying the spatial immunohistochemical distribution of three primary antioxidant enzymes (AEs). Nineteen normocholesterolemic New Zealand White rabbits were divided into two groups: normotensive controls (NT; n = 6) and 13 animals rendered hypertensive by surgical coarctation of abdominal aorta. The hypertensive group was subdivided into hypertensive alone (HT; n = 8) and hypertensive treated with 1% probucol (PO) for 9 weeks (HT-P; n = 5). Blood pressure rose significantly in both hypertensive groups (P < .005). At autopsy, both hypertensive groups showed similarly significant increases in mean arterial intima-media thickness (IMT) whether or not they were treated with probucol. However, only HT rabbits revealed significant increases in the intima-media depth penetration of glutathione peroxidase, superoxide dismutase, and catalase AEs. By contrast, in HT-P animals probucol produced significant reductions of immunostaining of all three AEs compared to the HT group (P < .05). Additionally, specific macrophage immunostaining revealed that the arterial wall of HT rabbits had numerous (10 to 12 per high power field) subintimal and medial macrophages as compared to the HT-P animals (1 to 2 per high power field). The blood pressure level correlated significantly with IMT in all three groups, but with depth penetration of the three AEs only in the NT and HT groups. Probucol, therefore, appears to act in concert with the native arterial antioxidant enzymes as a potent free radical scavenger to reduce oxidative stress and thus attenuate the macrophage invasive response in hypertensive arteries.
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This organ burdens of uranium were estimated for an urban Indian (Bombay) population living in a normal background environment, using the technique of neutron activation analysis, in combination with post-irradiation chemical separation. The total organ burdens were: skeleton > muscle > soft tissue > lungs > kidney > liver > heart. A comparison was made between the observed organ burdens of uranium for skeleton, kidney, and muscle with those obtained by applying the metabolic model of uranium as recommended by International Commission on Radiological Protection (ICRP) to its daily intake by urban population. The observed organ burdens for kidney and muscle were found to be 4 and 70 times higher than the derived burden values; however, the two estimates were similar in the case of skeleton. This observation indicated that the clearance half-lives for uranium present in kidney and muscle tissue are likely to be longer than those reported by ICRP. For skeleton, however, the clearance half-life reported by the ICRP appeared to be reasonable.
The four important parameters involved in the calculation of internal radiation dose to the human body, per unit intake of a radionuclide are 1) weight and size of the body organs; 2) the biological (retention) half-life of the radionuclide; 3) radiation weighting factors for the type of radiations emanating from the radionuclide; and 4) the organ weighting factors for the organs being irradiated (target organs). Whereas, for a particular radionuclide, the radiation weighting factor and the organ weighting factors may remain constant for all humans, the other two parameters, namely, the organ weights and biological half-life, are population specific and may differ from one population group to another. For a realistic dose estimation, the population specific data on organ weights and biological half-lives for various radionuclides therefore, are needed.