Methods will be developed and validated fore quantifying human exposure to potent dietary mutagens. We will focus on amino- imidazoazaarenes (AIAs), chemical mutagens formed in meats by moderate temperature cooking and therefore widely consumed in the American diet. These chemicals are potent mutagens in the Ames/Salmonella bacterial mutagenesis assay and, where they have been tested in long-term bioassays, are carcinogens. It is only in the past 5-6 years that a subset of these compounds have been isolated, identified and synthesized in sufficient quantities for studies on their mechanisms of action. The next logical step in determining the human health risk posed by these chemicals requires quantification of their levels in the diet. In many ways the exposure to cooked-meat mutagens is prototypic of environmental and occupational exposures to aromatic amines. There is chronic low level exposure to low doses of a complex mixture of chemicals for which only a subset of the biologically active ones have been identified structurally. Our studies will provide a comprehensive approach for using immunological methods for chemical dosimetry in a complex mixture where the biologically active molecules are present in the part per billion level. We already have monoclonal antibodies (isolated and partially characterized during the first 2 years of the grant) that recognize specifically 3 of the metagenic AIA compounds and a set of others that are class specific. Interestingly, all three of the specific antibodies see cross-reacting material in the meat fractions following HPLC separations, but they do not see any of the structurally related isomeric standards. In this proposal we will validate the immunochemical methods previously developed to quantify the AIA mutagens, IQ, MeIQx, PhIP, DiMeIQx, and MeIQ in cooked-ground beef (specific aim 1). Once validated, we will use the immunoassay to examine the AIA content office additional cooked foods (specific aim 2) Immunoassay will be performed after bulk clean up and the first preparative HPLC run. The quantitative results obtained will be compared to those recorded for fried -ground beef and those obtained by conventional analytical means for the other foods. Unknown mutagens and major cross-reacting chemicals will be purified using affinity chromatography and identified using MS and NMR analysis (specific aim 4). The most mass abundant mutagens will be synthesized and further characterized (specific aim 5). Finally, with the understand of the types and quantities of these potent mutagens/carcinogens and major cooked foods in our diet, we can make a better estimate of the risk to human of the risk to humans of their daily consumption.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA040811-05
Application #
3181088
Study Section
Metabolic Pathology Study Section (MEP)
Project Start
1985-09-30
Project End
1993-11-30
Budget Start
1990-12-17
Budget End
1993-11-30
Support Year
5
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Lawrence Livermore National Laboratory
Department
Type
Organized Research Units
DUNS #
827171463
City
Livermore
State
CA
Country
United States
Zip Code
94550
Felton, J S; Wu, R; Knize, M G et al. (1995) Heterocyclic amine mutagenicity/carcinogenicity: influence of repair, metabolism, and structure. Princess Takamatsu Symp 23:50-8
Malfatti, M A; Buonarati, M H; Turteltaub, K W et al. (1994) The role of sulfation and/or acetylation in the metabolism of the cooked-food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in Salmonella typhimurium and isolated rat hepatocytes. Chem Res Toxicol 7:139-47
Felton, J S; Knize, M G; Dolbeare, F A et al. (1994) Mutagenic activity of heterocyclic amines in cooked foods. Environ Health Perspect 102 Suppl 6:201-4
Vanderlaan, M; Hwang, M; Djanegara, T (1993) Immunoaffinity purification of dietary heterocyclic amine carcinogens. Environ Health Perspect 99:285-7
Murray, S; Lynch, A M; Knize, M G et al. (1993) Quantification of the carcinogens 2-amino-3,8-dimethyl- and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in food using a combined assay based on gas chromatography-negative ion mass spectrometry. J Chromatogr 616:211-9
Knize, M G; Felton, J S; Gross, G A (1992) Chromatographic methods for the analysis of heterocyclic amine food mutagens/carcinogens. J Chromatogr 624:253-65
Lynch, A M; Knize, M G; Boobis, A R et al. (1992) Intra- and interindividual variability in systemic exposure in humans to 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl- 6-phenylimidazo[4,5-b]pyridine, carcinogens present in cooked beef. Cancer Res 52:6216-23
Felton, J S; Turteltaub, K W; Gledhill, B L et al. (1991) DNA dosimetry following carcinogen exposure using accelerator mass spectrometry and 32P-postlabeling. Prog Clin Biol Res 372:243-53
Vanderlaan, M; Alexander, J; Thomas, C et al. (1991) Immunochemical detection of rodent hepatic and urinary metabolites of cooking-induced food mutagens. Carcinogenesis 12:349-54
Felton, J S; Knize, M G (1990) New mutagens from cooked food. Prog Clin Biol Res 347:19-38

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