Cytogenetic Studies in Human Populations Exposed to Gas Leak at Bhopal, India

Abstract

Frequencies of chromosomal abnormalities, sister chromatid exchanges, and replicative index were assessed following peripheral lymphocyte culture in 129 individuals from Bhopal, India. Ofthese, 83 persons (40 male and 43 female) had been exposed directly to the methyl isocyanate (MIC) gas after the accident at the Union Carbide plant on December 2 and 3,1984. The remaining 46 samples were taken from age-matched unexposed persons in the same city. Chromosome aberrations were recorded at first cycle metaphase (Ml) and sister chromatid exchanges, at second cycle metaphase (M2), following standard schedule. The frequency of chromosomal aberrations was, in general, higher in individuals from the exposed populations, with the females showing a higher incidence. Nondisjunction of chromosomes or laggard was rare. The frequencies of sister chromatid exchanges and depression in mitotic and replicative indices could not be related to exposure or sex. The persistence ofchromosomal abnormalities in the form of replicating minutes and exchange configurations, even 1114 days after exposure to the gas, may indicate a residual effect on T-cell precursors.

Induction of genomic instability in cultured human colon epithelial cells following exposure to isocyanates

“…Developing methods for studying genome-wide effects of occupational or inadvertent exposure to environmental contaminants, which affect human health, and elucidating the molecular mechanisms of these effects are now major concerns. Isocyanates, including MIC have wide industrial applications, although they are mutagenic, alter the genome (Mason et al, 1987;Anderson et al, 1988;Kar et al, 1989) and can produce varied chromosomal abnormalities in individuals exposed to them (Goswami et al, 1990;Ghosh et al, 1990). There are reports that defects in the cellular response to DSBs can lead to genetic alterations, chromosomal instability, and ultimately malignant transformation (Mills et al, 2003).…”

“…It may induce DNA damage, apoptosis, over‐expression of cytokines and genomic instability (Kundu and Surh, 2008). Therefore down regulation of components of the DNA damage response mechanisms could enhance genomic instability and facilitate the proliferation of pre‐cancerous cells (Gorgoulis et al., 2005). As MIC can initiate DNA damage, apoptosis, oxidative stress and inflammation in cultured human lymphocytes (Mishra et al., 2008), it is very likely that it is linked to genomic instability.…”

Methyl Isocyanate

“…In a study involving 43 gas-exposed women and 40 gas-exposed men 3 years after the disaster, a significant increase in chromosomal aberration was reported; these aberrations included breaks, gaps, and dicentric rings, which were more marked in females than in males (Ghosh et al, 1990). Chromosomal aberrations (Goswami, 1986;Ghosh et al, 1990) and cell cycle abnormalities have been identified in Bhopal victims (Deo et al, 1987).…”

“…Chromosomal aberrations (Goswami, 1986;Ghosh et al, 1990) and cell cycle abnormalities have been identified in Bhopal victims (Deo et al, 1987).…”

Neurocognitive function in women affected by the Bhopal gas disaster

“…after the accident on a sample of 40 exposed males and 40 exposed females revealed a statistically higher frequency of chromosomal aberrations among those exposed compared with non-exposed controls. 3 These chromosomal aberrations were more pronounced in females.…”