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Biomedical subjects

S K Hazra

Publications and source records attributed to S K Hazra.

At least 19 recordsLinked to original sources
PubMed1999

Association of vitamin D receptor genotype with leprosy type.

Host genetic factors including major histocompatibility complex (MHC) polymorphisms influence both susceptibility to leprosy per se and also to leprosy type. Non-MHC genes may play an important role, but such genes remain undefined. The influence of two non-MHC candidate genes was assessed in a case-control study of Bengali leprosy patients from Calcutta. Recent studies have implicated variation in the vitamin D receptor (VDR) gene in susceptibility to several diseases, including osteoporosis and pulmonary tuberculosis. In this population, homozygotes for the alternate alleles of the VDR polymorphism are associated, respectively, with lepromatous and tuberculoid leprosy. The NRAMP1 (natural resistance associated macrophage protein 1) gene may influence human mycobacterial disease susceptibility based on studies with the murine homologue Nramp1. However, no significant association was found between NRAMP1 and leprosy susceptibility. This study suggests that the VDR polymorphism may influence susceptibility to some diseases by affecting the type and the strength of the host immune response.

Alleles↗
PubMed1997

Tumor necrosis factor promoter polymorphism and susceptibility to lepromatous leprosy.

Genetically determined differences in immune responses to environmental agents may underlie susceptibility to many autoimmune and infectious diseases. Leprosy provides an example of a polarity in the type of immune response made to an infectious agent, and there is evidence that the major histocompatibility complex is genetically linked to leprosy type. It was found that HLA-DR2 is associated with both tuberculoid and lepromatous types of leprosy; however, a variant at position -308 of the promoter of the neighboring tumor necrosis factor (TNF) gene was increased in frequency in lepromatous (odds ratio = 3.0, P = .02) but not tuberculoid leprosy. Some studies have found higher serum levels of TNF in lepromatous than tuberculoid leprosy, and high TNF levels are found in malaria and leishmaniasis, which are also associated with this TNF allele. It is speculated that this association reflects genetic variability in cytokine production, which influences the immune response to and clinical outcome of leprosy.

Adult↗
PubMed1994

An eight-year field trial on antileprosy vaccines among high-risk household contacts in the Calcutta metropolis.

One-hundred-seventy-nine lepromin-negative household contacts were vaccinated with heat-killed Mycobacterium leprae, BCG, or a combination of the two. Vaccination induced lepromin positivity in 131 of these contacts. Over an 8-year follow-up period, 12 lepromin-positive contacts developed leprosy, all tuberculoid; while 2 lepromin-negative vaccinated contacts developed leprosy, both lepromatous. Overall, 7.8% of the vaccinated contacts developed the disease. Seven-hundred-fourteen household contacts were not vaccinated, and served as controls. Among the 504 who were lepromin positive, leprosy developed in 35, all tuberculoid, over the 8-year follow up. Among the 210 lepromin-negative unvaccinated contacts, 61 developed leprosy: tuberculoid in 29, borderline in 4, lepromatous in 8, and indeterminate in 20. Overall, 13.5% of the 714 unvaccinated contacts and 29.0% of the 210 unvaccinated, lepromin-negative contacts developed leprosy. Vaccination could not induce lepromin positivity in all contacts. The three vaccines were equally effective in inducing lepromin positivity. Vaccination reduced the overall incidence of leprosy from 13.5% to 7.8% among household contacts but did not reduce the incidence of lepromatous leprosy (1.2% of all the vaccinated and 1.1% of all the unvaccinated contacts).

BCG Vaccine↗
PubMed1982

Corticosteroids and lepromin sensitivity.

Corticosteroids are known to influence the hypersensitivity reaction in a number of diseases involving hypersensitivity of tissues and alter the antigen antibody reactions in vivo. Corticosteroids administered in thirty tuberculoid cases for a period of 3 weeks showed negative response in the lepromin positive cases uniformly thereby proving suppression of cell mediated immunity in tuberculoid cases under the influence of corticosteroids; hence polar concept of tuberculoid type may be under question with continuous and prolonged corticosteroid therapy under necessity.

Adolescent↗
PubMed1979

Nature and familial character of lepromin sensitivity in 27 families and their siblings.

A group of 27 families consisting of 176 individuals had been investigated for the lepromin sensitivity (with Dharmendra antigen). The families were arranged under group A (9 families) in whom either of the parents or both were suffering from Lepromatous type of leprosy, group B numbering 4 families, of whom either of the parents or both were suffering from non-lepromatous type of leprosy and group C comprising 14 families where none of the parents was suffering from leprosy but some of the each family had the disease in their siblings. The present study points towards the possible genetic influence on lepromin sensitivity but at times may be influenced by the environmental factors. However the study does not permit to reach any valid conclusions; further elaborate investigations alone could prove the useful role of genetic influence in the propagation of lepromin sensitivity to the subsequent sibs.

Adolescent↗
PubMed1978

EMS-induced reversion studies in the white locus of Drosophila melanogaster.

5 white-locus mutants of Drosophila melanogaster, respresenting 5 different sub-sites, were treated with EMS and tested for reversion to wild-type. 4 of them were genuine mutants and one was not. Moreover, the ability of the 4 mutants to revert to wild-type differed from one another which therefore reflects a qualitatively distinct alteration in the genetic material delimited by each mutant.

Animals↗
PubMed1977

Clinical trial with rifampicin in the treatment of leprosy (final report).

A controlled trial of Rifampicin plus Dapsone had been in progress for two years in the Department of Leprology, School of Tropical Medicine, Calcutta. Interim results of this trial after six months treatment were reported in 1976. The present paper is the final report of the study after two years of treatment. The study reveals that with Rifampicin, MI falls rapidly after six months, but changes in BI are not better than in the DDS group. As a matter of fact, regarding BI, treatment with DDS has given better results as two cases have become negative in the DDS group while no case has become negative in the Rifampicin group. It is, therefore, concluded that clinical improvement with Rifampicin is similar to that with DDS.

Clinical Trials as Topic↗
PubMed1976

Clinical trial with rifampicin in the treatment of leprosy.

Rusults of treatment with Rifampicin in ten untreated and uncomplicated cases of active lepromatous leprosy are compared with those of D.D.S. in a similar number of cases. Though clinical improvement was similar in both the groups, improvement in B.I. and M.I. appears to be better in the latter group. High price of Rifampicin is its greatest drawback at present.

Adolescent↗