Search for chromosomal variations among gas-exposed persons in Bhopal

Abstract

A chromosomal survey using standard lymphocyte cultures employing different media and G-banding techniques was initiated in 1984. This study became particularly important following the tragic gaseous exposure of the population in Bhopal at midnight on 2 December 1984. We have been able to formulate a chromosomal profile for each person whom we have studied; during 1986-1988, 154 persons were examined twice. Among seemingly normal individuals, as many as 20% might possess some chromosomal abnormality; of these, 50% may develop, at a later date, some kind of pathological complication (such as tumours, recurrent abortion or transmission of defects to their offspring). The people exposed to methyl isocyanate have repeatedly shown Robertsonian translocations, mostly in acrocentric chromosomes 13 and 21. Other types of translocations have been studied among all exposed (53) and normal (101) persons; the involvement of chromosomes 5, 9, 11, 14 and 16 is statistically significant (P = less than 0.001). One of the major clinical symptoms is dyspnoea; we have estimated that almost all seriously dyspnoeic patients have developed at least two categories of chromosomal aberrations, one of which is Robertsonian translocation, in at least 10% metaphases. Our chromosomal survey will be of significance because we are able to identify people with chromosomal aberrations that might be correlated with future pathological consequences of the accident. The "chromosomal load" that can be sustained with an apparently normal phenotype can also be measured.

Gross Chromosomal Aberrations are Early Alarms for Malignancy: A Re-Emphasis

“…These included 212 apparently normal individuals, 60 mentally handicapped children and adults, 82 methylisocyanate gas exposed persons (Union carbide tragedy, Bhopal, mid night 2 nd to 3 rd Dec 1984), 86 persons with syndromes and diseases, and 165 individuals complaining about fertility and abortions. Standard protocols were followed on cultures using different culture media and staining procedures included simple Giemsa, orcein and Feulgen's techniques; a few slides of each category (Tables 1 and 2) were also processed for C and G banding [20][21][22][23] Following specific aberrations were scored: Chromosome breaks, Somatic translocations, Acrocentric associations, Marker dots, Premature centromeric divisions, Tandem duplications, Hyperploid cells, Hypoploid cells, Amitotically dividing nuclei and unusual association of chromosomes or chromatids. These details have been mentioned in earlier publications [15,[19][20][21][22][23][24] Blind scoring of slides continued for a long time in search of chromosomal aberrations with alarming attention for "marker dots"; the chromatin dots discovered and observed since 1973 [18].…”

“…This work is based on vigilant examination of thousands of slides of cultured lymphocytes for chromosome studies and this was recoded that MDs were typically expelled from chromatids of specific chromosomes [19]. Marker dots have been reported in various syndromes and methyl isocyanate exposed persons [15,[20][21][22][23]. Since MDs are expelled from many chromosomes in many malignancies like breast cancer, colon cancer, Wilm's tumor, bone cancer ( Figure 4) and also in some seemingly normal persons from families having cancer incidence among parents and real sibs who may be prone or susceptible for malignancy.…”

Genotoxic and Carcinogenic Effects of Methyl Isocyanate (MIC) Reviewed on Exposed Bhopal Population and Future Perspectives for Assessment of Long-Term MIC-Effect

“…The paper has not addressed the possible consequences at cellular or genetic level. In a later publication by Goswami et al [38], the result was highly criticized by scientific fraternity and recommended withdrawal from the journal [39]. The figures showing Robertsonian translocations are simply association of acrocentric chromosomes, and the metaphase with arrowed chromosomes are not showing any deletion.…”

“…Giemsa banding was of substandard quality and not appreciable for chromosome-classification. It is surprising that the Human Genetics journal had reviewed and published the articles of Goswami [27,38]. Another publication by Ghosh et al [26] documented chromosomal aberrations including self-replicable double minutes, breaks, gaps, dicentrics, rings and tri-and quadriradial chromatid exchanges etc., and SCEs on 129 MIC-exposed individuals 1114 days post exposure, which were more pronounced in females.…”

The Epidemiology of Disasters and Adverse Reproductive Outcomes: Lessons Learned

“…The slight increase observed in perinatal and neonatal mortality was not statistically significant. Goswami et al focused their study on chromosomal variations among persons exposed to isocyanide as a measure of genetic damage (40). They found no difference in the rate of chromosomal variation between subjects exposed to isocyanide and those who were not.…”