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Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 19 recordsLinked to original sources
PubMed1992

Zirconium. An abnormal trace element in biology.

The action of Zirconium (Zr) on biological systems presents an enigma. It is ubiquitous, being present in nature in amounts higher than most trace elements. It is taken up by plants from soil and water and accumulated in certain tissues. The entry into animal systems in vivo is related to the mode of exposure and the concentration in the surrounding environment. Retention is initially in soft tissues and then slowly in the bone. The metal is able to cross the blood brain-barrier and is deposited in the brain and the placental barrier to enter milk. The daily human uptake has been known to be as high as 125 mg. The level of toxicity has been found to be moderately low, both in histological and cytological studies. The toxic effects induced by very high concentrations are nonspecific in nature. Despite the presence and retention in relatively high quantities in biological systems, Zr has not yet been associated with any specific metabolic function. Very little information is available about its interaction with the compounds of the genetical systems, such as nucleic acids. Apparently, the metal is neither an essential nor toxic element in the conventional sense. However, the increasing exposure to this element through its increasing use in new materials and following radioactive fallout, has increased the importance of the study of its effects on living organisms. The tetravalent nature of the ionic state and the high stability of the compounds formed are important factors that need to be considered, as also the accumulation of this element in the brain, reminiscent of the relationship between Al3+ and Alzheimer's disease.

Animals↗
PubMed1992

Health profile of pregnant adolescents among selected tribal populations in Rajasthan, India.

Among primitive tribal communities in India, girls are traditionally married immediately after attaining menarche. In the present study all adolescent girls in the second and third trimesters of pregnancy from 15 randomly selected villages of 4 tribal development blocks of Udaipur district (South Rajasthan State, India) were studied. The data were analyzed with reference to parity, anthropometry, anemia, and other dietary deficiencies. A total of 54 adolescent girls (13-19 years of age) were included in the present study. Of these, 59% (n = 32) were found to be primigravidas, 30% (n = 20) were pregnant for the second time, and 2 girls were pregnant for the third time. A majority were illiterate (n = 46), and almost all of them were found to be suffering from moderate-to-severe anaemia (n = 51). Similarly, a large majority (n = 46) had a body mass index (BMI) less than normal and body weight less than 42 kg. Two of the pregnant girls were also found to be suffering from pellagra, while approximately one-third of the girls had vitamin A deficiency. Only 2 had ever practiced family planning, consisting of some herbal preparations given to them by the folk doctor. Of the study participants, 19 girls (35.0%) were in the third trimester of pregnancy; of these, 7 had evidence of malpresentation or cephalopelvic disproportion. This study highlights the health profile and needs of pregnant adolescents among tribal populations in a drought-affected area in India.

Adolescent↗
PubMed1992

Plasmodium falciparum invades human red cells via a parasite produced glycosidase.

This report describes that P. falciparum produces a neuraminidase like activity on invasion into erythrocytes in culture on the basis of biochemical and immunological investigations. This activity in turn modifies the surface glycoprotein receptors of red cells and may be of help in the inhibition of further invasion by merozoites. The characterization of this enzyme activity may help elucidate the mechanism of cerebral malaria.

Animals↗
PubMed1979

The directional absorption properties of rhodopsin and its photoproducts.

The experimental data on the absorption of a plane polarised light by a solution of cattle rhodopsin at -196 degrees C have been theoretically analysed to model the directional absorption properties of rhodopsin and its photoproducts. It is seen that these molecules behave like planar absorbers having a ratio of about 100 : 7 between the extinction coefficients along the long axis and perpendicular to it. Using this result and the experimental observations on absorption and dichroism in the retina in situ, a model for the configuration of chromophores in the disc membranes has been derived. In this model the plane of the chromophore is perpendicular to that of the disc and the long axis of the chromophore makes an angle of 6.6 degrees with the plane of the disc. The solution of the problem depends on the assumption that the absorption axes are the same for the rhodopsin, prelumirhodopsin and isorhodopsin.

Animals↗
PubMed1978

Hemoglobin variants in India.

The occurrence of different types of hemoglobin variants in India has been well-documented in urban populations and in certain tribal areas. Beta-thalassaemia and hemoglobins D,E,H,S, and rare variants like Hb Lepore, have been found in varying percentages. There is a higher incidence of Hb E in the Eastern region and of Hb D in certain Northern populations. The association of Hb E with beta thalassaemia G6PD deficiency has been established. The relationship with other environmental factors, like malaria, is not yet clear.

Environment↗
PubMed1978

Total protein patterns in human amniotic fluid.

Total protein patterns of amniotic fluid samples of different age groups, following polyacrylamide disc gel electrophoresis, showed a wide range of variation in early pregnancy, but no two cases had identical banding, indenticating their genetic variability. An assessment has been made here of the total protein, albumin and transferrin patterns from normal fluids of different age groups by gel electrophoresis, in order to observe the genetic variations and relationship with foetal age, if any.

Albumins↗
PubMed1978

A study of relationship between pulmonary tuberculosis and palmar dermatoglyphic traits.

Bilateral inked palmar impressions of 150 male tubercular patients and those of 150 normal controls (males) have been studied comparatively. Patients and controls show deviation from each other with respect to 1. biological concordance-disconcordance in line C and hypothenar patterns, 2. bilateral and left-homolateral (not right) differences in Plato's modal types of line C and 3. occurrence of hypothenar (R + L only) and III interdigital patterns (L-homolateral only). It is significant that tubercular patients do not show any difference with the normal controls in a reliable measure like main-line-index and by and large in occurrence of patterns also (with two exceptions only). Natural selection does not seem to be operative on palmar dermatoglyphic traits.

Anthropometry↗