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Biomedical subjects

R S Sharma

Publications and source records attributed to R S Sharma.

142 records · Page 8Linked to original sources
PubMedDate not supplied

Epidemiological evaluation of oral polio vaccine efficacy in Delhi.

Forty seven cases of poliomyelitis and 94 controls were studied for immunization status. Unmatched analysis with one control per case and two controls per case was done to find out the ratio of the odds of immunization in diseased individuals as compared with the nondiseased (odds ratio). This ratio (OR) was used further to calculate oral polio vaccine efficacy. OPV efficacy was found to be 93% with 95% confidence limits of 75-98%.

Case-Control Studies↗
PubMedDate not supplied

Acute paralytic poliomyelitis in Delhi (1975-1992).

Incidence of poliomyelitis in Delhi between 1975 and 1992, estimated from available data, shows a ladder-pattern type of decline from 15.65 in 1975 to 5.90 in 1992. The linear regression analysis shows a declining trend of incidence by 66.28% during the period. Huge increase of population with fast growing slums and resettlement colonies in Delhi was attributed to be responsible for partly counteracting different poliomyelitis control/eradication activities. The population representativeness of estimated incidence showed constant improvement during 1980 to 1991.

Humans↗
PubMedDate not supplied

Effects of long-term administration of androgens and estrogen on rhesus monkey prostate: possible induction of benign prostatic hyperplasia.

Rhesus monkeys were used to investigate the role of androgenic steroids and estradiol in the induction of hyperplastic changes in stromal and glandular prostate tissues. Adult male rhesus monkeys were procured from the wild and, after routine quarantine procedures, were randomly divided into 5 groups of 5 animals each. Gluteus maximus muscles were injected with 2.5 mg of androstenedione (Group II), 2.5 mg of dihydrotestosterone (DHT) or 0.25 mg of estradiol (Group II), 2.5 mg androstanediol (Diol; Group IV), or Diol in combination with 0.25 mg of estradiol (Group V). Group I consisted of untreated controls. Animals were injected with steroids 3 times a week for 2 years. Treatment with androstenedione (Group II) resulted in stromal hyperplasia in the caudal lobe and an increase in epithelial cell height in all zones except in the central zone of the caudal lobe. In monkeys treated with DHT and estradiol (Group III), stromal hyperplasia in both lobes, a decrease in tubular size, and degranulation and vacuolation of epithelial cells were noticed. Injection of Diol alone (Group IV) or in combination with estradiol (Group V) resulted in a widening of stroma in the central and peripheral zones of cranial and caudal lobes, whereas the tubular size decreased. Diol also induced epithelial cell hypercellularity in the central and peripheral zones of the caudal lobe and in the peripheral zone of the cranial lobe. Prostate-specific antigen levels in Group IV animals gradually increased from 6 months of treatment and were maximal after 18 months of injections. Serum estradiol levels increased to detectable levels in all groups except Group IV. Serum testosterone levels decreased to very low or undetectable levels in all groups, whereas prostate-specific acid phosphatase increased in all treated groups. Prolactin levels were elevated in all treated groups except in animals injected with androstenedione. These results indicate that repeated long-term injections of androstenedione or DHT and estradiol induced stromal hyperplasia, which may be an estrogen-related effect. Androstanediol-induced hypercellularity and stratification of glandular epithelium is comparable to human prostatic intraepithelial neoplasia. These results also suggest that the rhesus monkey is a suitable animal model for experimental induction of prostate diseases.

Androstane-3,17-diol↗
PubMedDate not supplied

Structure of rete testis, vas efferens, epididymis and vas deferens of langur monkey (Presbytis entellus entellus Dufresne).

Morphological and histological features of rete testis, vas efferens, epididymis and vas deferens were studied in the langur monkey. Tubular extensions of rete were located towards lateral side of the testis. Its epithelium comprises mostly of cuboidal cells with hyaline cytoplasm. Three to nine bundles of vas efferens, emerging below the cranial pole of the testis, were observed. Vas efferens epithelium comprises of ciliated and nonciliated cells. Epididymis could be divided into six zones on the basis of cytological features. Principal cells, basal cells, apical cells and intraepithelial lymphocytes were observed in the epididymal epithelium, but their number, shape, size and location of nuclei varied in different zones. Vas deferens epithelium comprises of principal cells, basal cells, apical cells and few intraepithelial lymphocytes. Epithelium is surrounded by lamina propria, longitudinal, circular and longitudinal muscle layers.

Animals↗
PubMedDate not supplied

Alveolar stability of altitude raised rats.

On the lining of alveolar membrane of the lung presence of surfactant, a surface tension lowering agent which is a phospholipid in nature, is well established. A good correlation exists between pulmonary lecithin, the principle constituent of surfactant system and alveolar stability. The production of surface active material in the type II cells is oxygen dependent and is affected by hypoxia. The chemical and physical nature of the surfactant in the lungs of the rats raised at high altitude has been studied in comparison with that of sea level control. Eighteen male adult rats raised at high altitude (3520 m) were used. Phospholipids (Phosphatidyl Choline, Phosphatidyl ethanolamine, Lysophosphatidyl choline, Lysophosphatidyl ethanolamine and Sphingomyelin) were estimated by thin layer chromatography, stability index by Pattle's bubble technique and dynamic surface tension have also been studied to assess the surfactant activity of the lung. The results indicate that there was a decrease in lung surfactant as measured by chemical analysis. However, stability ratio measurements showed that there was very little change in the stability ratio (Sr) as the value of both groups lay in the normal range namely 0.6 to 0.9 hence the lungs of high altitude raised rats had normal alveolar stability. Surface tension values of alveolar lavage in altitude raised animals were also similar to those of normal rats. It is concluded that the rats raised at altitude show a lowering of surfactant as estimated chemically but the stability ratio is not significantly altered to indicate alveolar instability. In the altitude rats lesser quantum of surfactant is adequate to maintain alveolar stability.

Altitude↗
PubMedDate not supplied

Tobacco smoking in a defined community of Delhi.

A Community based study was conducted in urban Delhi. It was found that Smokers constituted about 32 percent of adult males in Delhi Admin. Flats, Timarpur. Proportion of smokers was highest in 41-50 years age. 31 percent of school teachers were smokers. Out of all who tried to live-up smoking, 8 percent reverted back after abstinence of two year or more. About three fourth of the smokers were worried ill effects of smoking's on them and others. Significantly higher number of non-smokers expressed opinion for total stopping of advertisement and complete ban of sale of smoking tobacco.

Adult↗
PubMedDate not supplied

Increased proliferation of Leydig cells induced by neonatal hypothyroidism in the rat.

Treatment of male rat pups with the reversible goitrogen 6-n-propyl-2-thiouracil (PTU), administered by adding 0.1% PTU to the mother's drinking water from birth through weaning, increases adult testis size, number of Sertoli cells, and daily sperm production. Adult Leydig cell numbers are also increased by 70%, despite permanent suppression of serum luteinizing hormone (LH). The present study was designed to test whether this effect results from an increase in proliferation of Leydig cells or the mesenchymal precursors. The labeling indices (LI) of six interstitial cell types were measured by tritiated thymidine autoradiography. With the exception of Leydig cells, LI declined after birth for all interstitial cell types in both control and PTU-treated rats, but mesenchymal cell proliferation was not significantly different in control and treated rats. In contrast, the LI of Leydig cells from PTU-treated rats rose by day 10, remained elevated through day 45 (highest on day 35 at 3.6-fold higher than control, P < 0.05), and declined to control values by day 50. The LI of Leydig cells in control rats was unchanged during the experiment. Proliferating Leydig cells were immature, as shown by their cytoplasmic lipid droplets. Adult Leydig cells, which lack lipid droplets, did not proliferate. Mesenchymal and immature Leydig cells contained thyroid hormone receptor mRNA; levels in adult Leydig cells were reduced but detectable. In conclusion, proliferation of Leydig cells, rather than increased proliferation of their mesenchymal precursors, is the principal mechanism responsible for the increase in Leydig cell number after neonatal hypothyroidism. Increased Leydig cell proliferation could result from direct effects of hypothyroidism on these cells. Alternatively, the increased Sertoli cell population that results from PTU treatment could also stimulate increased Leydig cell proliferation, or both of these mechanisms could contribute to the Leydig cell increase.

Animals↗