In efforts to further define the role of exposure to coal dust in subsequent development of gastric cancer, several studies have been performed and were highlighted in this report. In particular, consideration was given to the carcinogenic nature of coal dust once it has been introduced into the stomach of the miner either through inhalation, food ingestion or swallowing of air. Once in the stomach, the coal dust is acted upon by enzymatic or nonenzymatic nitrosation processes or through other interactions with exogenous chemicals which may turn the noncarcinogenic coal dust into carcinogenic compounds. Studies on the mutagenicity of different ranks of coal dust were conducted using the Ames Salmonella mutagenicity assay system. High mutagenic activity was found when extracts of bituminous, sub bituminous, and lignite coal dust were reacted with nitrite, a chemical found in the stomach, under acidic conditions. Studies on the effect of coal dust and its extracts on the interferon system indicated that nitrosated coal dust extracts at acidic conditions contain substances which are highly mutagenic and inhibitory for interferon induction. Virus infection studies were performed with the cytochrome-P-450 enzyme in efforts to understand the relationship between xenobiotic metabolism and antiviral activity in mice exposed to coal dust.
Department of Health and Human Services, NIOSH, Identification No. VKC - Mmy-108, 14 pages, 19 references