الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
During the last decades great number of chemical substances have been introduced to the environment due to rapid industrial development. Most of these substances are potentially toxic and many of them have genotoxic effects. There is a growing concern about the possible mutagenic and carcinogenic effect of mutagenic agents in human population exposed occupationally, accidentally or by life style. Some occupations may have an influence on the somatic and germinal cells of persons involved in such jobs. Damage to the genetic material of cells represents the initial events in the process that may eventually lead to manifestation of ill health. Cytogenetic monitoring is said to be the best and simplest available means for assessing genetic damage in occupational and environmental exposure to chemical agents. It involves the measurement of certain types of chromosome damage in human cells. Cytogenetic analysis of human chromosomes in peripherallymphocytes allows direct detection of somatic’cell mutation. Different methods can be used for chromosomal analysis: sister chromatid exchanges (SCEs), micronuclei ( MN ) and HGPRT locus assay. Exposure to mercury vapors represents a health hazard to workers of many occupations. These include chI or-alkali industry , 7.). thermometers factories, refineries, mines, fluorescent lamp manufacturing and in dental clinics. The health significance of mercury is largely due to the fact that, it has dangerous effect on central nervous system, kidneys, skin and Immune system. Furthermore, many recent studies revealed that mercury as a heavy metal has the ability to induce chromosomal damage and genotoxic effects. The majority of studies dealing with the cytogenetic monitoring of workers exposed to mercury vapors included chromosomal aberrations analysis, sister chromatid exchanges and micronuclei assay. Higher incidence of structural chromosomal aberration, aneuploidy and micronucleus among workers exposed to mercury vapors has been found. The present study has been carried out to throw more light on the genotoxic effect of occupational exposure to mercUl)’ vapors using different cytogenetic techniques ( micronuclei ( NIN ) , sister chromatid exchanges ( SCEs ) and HGPRT locus assay) and to evaluate the substantial effect of smoking on t1}e assessed parameters. A total number of 30 male workers, smokers ( n= 18 ) and non smokers (n=12 ) occupationally exposed to mercury vapors from ”Misr 96. Chemical Industries Company” have been selected for this study. A matched comparison group of 30 male workers smokers ( n=15 ) and non smokers ( n=15 ) was selected from” Edfina Company for Food Preservation” with no history of occ