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U.S. Department of Energy
Office of Scientific and Technical Information

Health effects of combustion-generated soot and polycyclic aromatic hydrocarbons. Task III

Technical Report ·
OSTI ID:6741196

The Genetic Toxicology Group has made specific progress under support of the Department of Energy which we believe deserves particular notice by our reviewers; We have found a diploid human lymphoblast line, HH4, which forms colonies when plated in soft agar without a feeder layer of human fibroblasts. The use of this cell line reduced the time of a mutation assay from twenty-eight to sixteen days. We have synthesized several potential fluorescent substrates for the enzyme HGPRT as a means to provide a fluorescent marker system for HGPRT-negative cells. Our studies have not found a feasible solution by this approach. We have tested the mutagenic potential of several defined soot samples against Salmonella typhimurium using our recently developed forward mutation assay at the xgprt locus. We have quantitatively assayed the mutagenic potential of sixty-two pure polycyclic aromatic hydrocarbon components of soot. We have demonstrated that dimethylsulfoxide extracts of crude soot may be studied directly in human cell assays in which post-mitochondrial supernatants derived from rat livers are used as the drug-metabolizing system. We have found that, on a weight basis, the dimethysulfoxide soot extract is as potent in causing human cell mutation as benzo (..cap alpha..) pyrene. Using a model mutagen, methylnitrosourea, we have found that while dose fracionation reduces the toxicity of chemical treatment, the reduction of mutagenic effects is much less pronounced. This finding indicates that simple cumulative models of mutation caused by long-term low-dose exposure of humans to environmental chemials may eventually be found to be accurate. Studies of means to freeze and store post-mitochondrial supernatants for mutation assay have indicated that high salt effects during freezing result in loss of certain drug-metabolizing activities.

Research Organization:
Massachusetts Inst. of Tech., Cambridge (USA). Energy Lab.
DOE Contract Number:
EE-77-S-02-4267
OSTI ID:
6741196
Report Number(s):
TID-28479
Country of Publication:
United States
Language:
English