Biomedical subjects
Publications and source records attributed to G Kumar.
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The substrate specificity of the acceptor site of peptidyltransferase of Escherichia coli 70 S ribosomes was investigated in Ac-Phe-tRNA . poly(U) . 70 S ribosome (system A) and tRNC-A-Phe . poly(U) . C-A-C-C-A-Phe . 70 S ribosome (system B) systems by using C-C-A-Gly, C-C-A-Phe, C-A-Gly and C-A-Phe as analogs of the 3'-terminus of aminoacyl-tRNA. It was found that an addition of CP residue to C-A-Gly and C-APhe resulted in an increase of the acceptor activity in system A; the increase is more remarkable for C-A-Gly than for C-A-Phe, while the acceptor activities of C-C-A-Gly and C-C-A-Phe are roughly similar. On the other hand, dramatically increased binding affinities of C-C-A-Phe and C-C-A-Gly relative to C-A-Phe and C-A-Gly for the A site of peptidyltransferase were observed in system B using an inhibition assay; C-C-A-Phe binds much more strongly than C-C-A-Gly. The results indicate the important role of the third CP residue and the aminoacyl moiety of the 3'-terminus of aminoacyl-tRNA in the interaction with the acceptor site of peptidyltransferase, as well as the existence of cooperative effects between A and P sites of peptidyltransferase. These effects, depending on an occupancy of P site, may significant the specificity of the peptidyltransferase A site.
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Active transport of calcium ions has been demonstrated in inside-out membrane vesicles from Mycobacterium phlei mediated by respiratory linked substrates as well as by ATP hydrolysis. The uptake of calcium exhibited an apparent Km of 80 microM and V of 16.6 nmol calcium uptake x min-1 x mg protein-1. A fortyfold concentration gradient for calcium ions was calculated for both the ATP-induced and the respiration-induced transport of calcium. Removal of coupling-factor-latent ATPase resulted in the complete loss of ATP-driven Ca2+ transport whereas the respiration-driven uptake was reduced by 40-50%. The uptake of calcium was inhibited by the proton conducting ionophores carbonylcyanide m-chlorophenylhydrazone and Gramicidin-D. The accumulated calcium was freely exchangeable with external calcium and was rapidly released by the addition of inhibitors of energy transduction, proton-translocating uncouplers or the ionophore A23187. The uptake of the weak base, methylamine, upon the oxidation of respiratory-linked substrates or the hydrolysis of ATP showed the generation of a protein gradient (inside acidic) which was partially collapsed on the addition of calcium ions. These results suggest that a Ca2+/H+ antiport mechanism may be responsible for the transport of calcium.
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All births (1211) were recorded in a rural area for 1985 by monthly domiciliary visits and the sociological characteristics were collected from mothers within a month. The analysis of 1201 births is presented: 52.7% were male births, 95.7% were delivered in village itself, 80.4% were delivered by trained dais, 99.5% were live born, 12.9% were born before 37 weeks of gestation, 61.5% were put to breast feed within 6 hours, 35% were of gravida 4 and above, 68.9% did not receive any antenatal care, 67.1% had not received any tetanus toxoid, 70.8% did not receive any folifer tablet, 0.8% had abortion and another 0.8% had still birth in preceding outcome, 1.58% had lost a live born dead in preceding out come, 89.6% stopped breast feeding at conception, 31.7% had birth interval less than 2 years, but 2.2% had less than one year, 2/3rd were born in second half of the year, 17.8% had taken extra food during pregnancy, 21.2% reduced the work after becoming pregnant, 9.5% were born to mothers of less than 20 years age, 98.5% of mothers were housewives and 95.9% mothers were illiterate, 33.5% were born in nuclear family, 22.3% were living in 'Kacha' house, 34.8% had no electricity connection, 37.0% were born to land less, 42.2% had no radio in the house, 7.1% had no conveyance, 52.0% families had piped water supply. These findings have been discussed here.
The prevalence of tobacco use among the school and college going adolescents of Haryana, a state in northern India was studied. 1130 male and 256 female students were given a self administered questionnaire regarding tobacco use. 160 (14.2%) male and 6 (2.3%) female students reported to have smoked at any time in the past. The prevalence of current smoking (defined as smoked in last one week) was only 7.1%. Of the 166 ever smokers, 44% had started this habit between 10 to 15 years of age. There was no rural-urban difference. Univariate analysis showed, male sex, age > 15 years, smoking by father, mother, sister, and friends to be significantly associated with smoking by the adolescent children. By logistic regression, only smoking by friend (O.R. 6.14), brother (O.R. 1.74) and male sex (O.R. 4.67) were found to be significantly associated with smoking by adolescent children. About 8% of the smokers were spending more than Rs. 10 per week on this habit. Both the smokers and non smokers were well aware of the adverse health effects of smoking indicating that mere provision of information on hazards of smoking may not be enough to reduce the prevalence of smoking. A more concerted effort for inducing behavioural change including legislation, communication is called for the fight against smoking.
This study was conducted at a secondary level hospital at Ballabgarth, run by Centre for Community Medicine, All India Institute of Medical Sciences. The still birth rate during the study period 1987-1992 was 19.5 per 1,000 births. It showed a sudden decline during these six years probably reflecting the change in the admission policy of the hospital. A case control study of 72 still births and 144 controls was carried out to identify risk factors for still births. Maternal age, gravidity, previous history of still births or abortion were not found to be significantly associated with still births. Poor socio-economic status measured by parental literacy and occupation were significantly associated with still births. Lack of antenatal care [(OR 9.2 (2.5-37.9)], low birth weight (< 2500 gms) [OR-18.1 (4.4-74.5)], non-vertex presentation [(OR 41.2 (66-257.3)], maternal illiteracy [OR 2.75 (1.01-11.3)] were found to be the important predictors of still birth as identified by logistic regression analysis. The provision of good antenatal care and improvement of the socio-economic status, especially female literacy, will help in decreasing the still birth rate in the country.
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BACKGROUND: With the increase in life expectancy, prevalence of impairments and disabilities are expected to increase in India. However, there have been very few studies to estimate the magnitude of the problem in rural India. This is essential, if appropriate rehabilitation services are to be planned in the country. METHODS: The study was done in the rural field practice area of the All India Institute of Medical Sciences at Ballabgarh, Haryana. The survey was conducted by successive batches of interns posted at Ballabgarh as a part of their compulsory rotating internship programme. The diagnostic criteria were based on history and simple clinical examination done at the domiciliary level. RESULTS: A total population of 25,509 in twelve villages were screened. The total impairment rate was 5.4% with no significant men/women difference. The prevalence of physical impairment was 4.7 per 1000 population. The prevalence of corneal opacity in children below 15 years of age was 4.7 per 1000. Prevalence of cataract was almost 35% in the population over 60 years of age and 15% in the population between 45 to 60 years. Auditory impairment was 19.6 per 1000 as ascertained by history. Three-fourths of this was conductive deafness and was found mainly in people above 60 years of age. CONCLUSION: Utilizing the rural field practice areas of medical colleges for collection of data on issues of national health importance would not only strengthen the health system in the country but also improve medical education. There is a need for a comprehensive preventive, promotive, curative and rehabilitative approach to disabilities in India.