A. B. Karnik

In vitro cytological and cytogenetic effects of an Indian variety of chrysotile asbestos

Abstract The cytotoxic and cytogenetic effects of chrysotile asbestos (Indian Variety, AP-I) in vitro on Chinese hamster ovary cells were investigated. Chrysotile asbestos (AP-I) produces high vacuolization of cytoplasm, flattening of cells with increased size, and chromosomal aberrations. Both cytological and cytogenetic studies were dependent upon the dose and the period of exposure to chrysotile asbestos.

Dominant-lethal study of technical-grade hexachlorocyclohexane in Swiss mice.

Male Swiss mice, 6-8 weeks old, were given a diet containing technical-grade hexachlorocyclohexane (BHC) at 500 ppm continuously for 4, 6 and 8 months. After the completion of the scheduled exposure period, the males were sequentially mated with 2-3 untreated virgin females at weekly intervals for 8 weeks. The females were autopsied at mid-term pregnancy for evaluation of dominant-lethal mutation. The number of dead implants, including deciduomas and dead embryos, showed a significant increase. Similarly, the percentage fertility and live embryos per female showed a decline when compared with the control

Clinical and biochemical investigations to evolve early diagnosis in workers involved in the manufacture of hexachlorocyclohexane

Summary365 individuals exposed to hexachlorocyclohexane (HCH) during its manufacture were studied and compared with 146 controls. These 502 cases were divided into five groups on the basis of serum total HCH levels. Exposure was mainly through skin. Results indicate that neurological symptoms reported were due to recent exposure to HCH and were related to the intensity of exposure. ECG abnormalities were seen in exposed cases. A significant positive correlation to liver related enzymes γ GT, LAP and Alp. P was observed. β -globulins significantly increased along with an increase in total HCH. Changes in IgM levels were similar as observed in IgA. Remarkably high concentration of HCH residues were found in the serum samples of all exposed workers. β-HCH contributed more than 80% of the total HCH built up. Presence of circulating immune complexes was also detected in representative samples. Further, repeated biological monitoring was advised to be carried out among such workers exposed to HCH, to evaluate signs of severe health impairment in them.

Effect of chrysotile asbestos (AP-I) on sister chromatid exchanges in Chinese hamster ovary cells

Abstract In vitro effect of an Indian variety of chrysotile asbestos from Andhra Pradesh (AP-I) is evaluated using sister chromatid exchanges (SCEs) in Chinese hamster ovary (CHO) cells. Cultures were treated for 24 hr with different concentrations of asbestos fibers, i.e., 0.1, 1, 10, and 100 μg/ml of medium. Sister chromatid exchanges were elevated even with the lowest concentration used. However, the linear relationship between SCEs and asbestos concentration is not seen.

Effect of cadmium chloride on cell division and chromosomes in Chinese hamster ovary cells

Effect of cadmium chloride on cell division and chromosomes was studied in Chinese Hamster Ovary (CHO) cells in vitro. The cell cultures were exposed to various concentrations of cadmium chloride. Different treatment of cadmium chloride resulted in various cell division abnormalities like micronucleus formation, lagging chromosome, and chromatid bridges. At higher doses, an abundance of pyknotic nuclei in the monolayer was noteworthy. The 24 hours continuous treatment caused chromosomal aberrations like chromatid gaps, breaks, exchanges and chromatid separation.

Experimental studies on insecticides commonly used in India

SummaryUsing hexachlorocyclohexane (BHC) as a model histopathological, histoenzymological, biochemical, and electrophoretic studies were undertaken to find out certain parameters for early diagnosis of liver cancer. In addition, cytogenetic studies were carried out to evaluate the effect of BHC feeding on mitotic and meiotic divisions. The results of these investigations suggest that there is a significant change in liver weight in experimental group. Histologically, liver cells follow a definite sequential cellular alteration ultimately leading to liver tumor. Histochemically, well defined pattern of glycogen accumulation and iron distribution in hepatocytes was observe. The electron-microscopic observation demonstrated prominently the proliferation of agranular endoplasmic reticulum in early stages. The distribution of certain enzymes linked with plasma membrane, lysosomes, and mitochondria showed the functional alteration of these organelles both in neoplastic nodules and tumours induced by BHC. The biochemical changes observed in gluconeogenic enzymes (G6Pase and F1,6dipase) and dehydrogenases (LDH, ICDH, and MDH) at different duration of exposure to BHC indicated decrease in enzyme activity of both gluconeogenic pathway and tricarboxylic acid cycle, linked with energy metabolism. These changes tend to recover with discontinuation of BHC but 8 months continuous feeding produces irreversible changes in G6Pase activity. Using polyacrylamide gel electrophoresis technique a change in serum proteins and LDH isoenzymes was observed. However, extrapolation of these findings to human situation needs more extensive studies, taking into account all possible variables, such as the DDT and BHC load in our environment and the body burden resulting there from.

Early changes in serum protein and liver LDH isoenzymes in mice exposed to technical grade hexachlorocyclohexane (BHC) and their possible relationship to liver tumours

Mice were exposed to hexachlorocyclohexane (BHC) in order to study the changes in the serum protein pattern and in the LDH isoenzymes of the liver. After 2 months of exposure the protein pattern showed a new band which persisted even after the development of a tumour. The LDH isoenzymes pattern showed a gradual decrease of the faster moving LDH-1 and LDH-2 bands which later disappeared completely when hepatic tumours formed. The significance of these results is discussed.

Experimental and Human Surveillance on BHC and DDT Insecticides Commonly Used in India

In India, the consumption of pesticides has increased more than 10 times during the last two decades, and it is now estimated that India will consume about 1,OOO,OOO tons of pesticides by 1990-91. Amongst the pesticides, the chlorinated hydrocarbon insecticides have drawn worldwide attention-and rightly so-on the basis of their persistence in the atmosphere without undergoing degradation. This has caused a good deal of concern as regards their adverse ecological effects. Moreover, the literature reveals that some of the persistent types of insecticides, such as DDT and BHC, are potentially carcinogenic in experimental animals. However, there is still a need for further in-depth studies to provide more information on the experimental evidence on their carcinogenicity. The present study was planned to evaluate the carcinogenicity in laboratory animals of these chlorinated insecticides, DDT and BHC, (technical grade) commonly used in India. The in-depth histopathologic, histochemical and biochemical changes during the process of hepatocarcinogenesis induced by BHC were also studied to find out the early sequential events leading to the genesis of liver cancer. In addition, cytogenetic studies were also carried out to evaluate the effect of BHC feeding on mitotic and meiotic divisions. Since the gamma isomer (Lindane) is the active principle, possessing insecticidal properties in technical BHC, its carcinogenic activity was also studied and compared with that of technical BHC. As a corollary to these laboratory tests, epidemiologic or field survey studies were also undertaken in a high-risk population (i.e., workers occupationally exposed to this insecticide while the workers were engaged in the manufacture of BHC at one of the factories in India. This study included medical examination of workers, biochemical investigations, especially related to liver and BHC residue levels in serum, in order to assess the environmental load of BHC and its potential ill effects on the health of workers.