Profiles of gene expression changes in L5178Y mouse lymphoma cells treated with methyl methanesulfonate and sodium chloride.

Treatment of cells with genotoxic chemicals is expected to set into motion a series of events including gene expression changes to cope with the damage. We have investigated gene expression changes in L5178Y TK(+/-) mouse lymphoma cells in culture following treatment with methyl methanesulfonate (MMS), a direct acting genotoxin, and sodium chloride (NaCl), which induces mutations in these cells through indirect mechanisms at high concentrations. The mouse lymphoma cells were treated for 4 or 24 h and the cells were harvested for RNA isolation at the end of the treatment.

Evaluation of the potential of triethanolamine to alter hepatic choline levels in female B6C3F1 mice.

Triethanolamine (TEA), a widely used nongenotoxic alcohol-amine, has recently been reported to cause an increased incidence of liver tumors in female B6C3F1 mice, but not in males nor in Fischer 344 rats. Choline deficiency induces liver cancer in rodents, and TEA could compete with choline uptake into tissues. The potential of TEA to cause choline deficiency in the liver of these mice as a mode of tumorigenesis was investigated.

An in vitro screening paradigm for extracts of whole foods for detection of potential toxicants.

The application of organic, conventional and biotechnology techniques can alter the intrinsic levels of natural toxicants in crop foods and methods are needed to screen for unexpected changes in toxicant levels. We evaluated crude, aqueous preparations of 37 foods purchased from a local market in a battery of four in vitro mammalian toxicity screens. The foods were evaluated in one or more of the following tests: (1) cytotoxicity (37 foods) and (2) chromosomal aberration test (nine foods), both in Chinese hamster ovary cells, (3) limb bud micromass assay (nine foods) using 11-day old CD-1 mouse embryos and (4) estrogenicity (MCF-7 cells transfected with estrogen receptor and lucerifase reporter constructs, 12 foods).

Evaluation of the genotoxicity of 2,4-dichlorophenoxyacetic acid and its derivatives in mammalian cell cultures.

2,4-dichlorophenoxyacetic acid and its derivatives (collectively known as 2,4-D) are herbicides used to control a wide variety of broadleaf and woody plants. The genetic toxicity of an ester (2,4-D 2-butoxyethylester) and two salts (2,4-D isopropylamine and 2,4-D triisopropanolamine) was investigated in cultured mammalian cells. The end points used were the induction of chromosomal aberrations in primary cultures of rat lymphocytes and forward mutations at the HGPRT locus of Chinese hamster ovary cells.

Clastogenicity of isoamylene oxide to rat lymphocytes in culture.

The mutagenic activity of the aliphatic epoxide isoamylene oxide (2-methyl-2,3-epoxybutane) is not readily detectable in the standard Ames test. In this study, the clastogenic potential of isoamylene oxide was evaluated using an in vitro mammalian cell culture system. Approximately 48 h after establishing primary cultures of rat lymphocyte cultures, the cells were treated for 4 h with various concentrations of isoamylene oxide (50, 166.