Mammalian cell culture mutagenicity test

Dean, B.J. and Danford, N. (1984). Assays for the detection of chemically induced chromosome damage in cultures mammalian cells. In Mutagenicity Testing. A Practical Approach, (Venitt, S. and Parry, J.M., Eds.). IRL Press, Oxford, pp. 187-232. 

Efficient mutagenicity tests that use experimental organisms and in vitro systems are a product of great advances in basic knowledge and of a substantial research effort. The principal task of the Committee is to study how the results of such tests can be used to assess the risk to future human populations. There are no reliable data from direct human experience, so it is necessary to rely on experimental test systems. Some tests are exquisitely sensitive to chemical mutagens, but use microorganisms or mammalian-cell cultures of uncertain relevance to human... 

In answer to the first question, the Committee suggests a two-tier system of inexpensive, short-term, sensitive mutagenicity tests that could be widely applied to identify substances that may represent a mutagenic hazard. The first tier uses one microbial test and two mammalian cell-culture tests. If the results of this tier are inconclusive, a Drosophila test (the second tier) is used. If the results are still insufficient for a manufacturing or control decision, further tests cure available, including those using mice. The test scheme is presented later in this summary and in more detail in Chapter 9. 

Large-scale mutagenicity testing is already under way. More than 12,000 chemicals had been tested by early 1981, mostly in Salmonella or mammalian cell-culture systems.11 Data are accumulating rapidly, and regulatory agencies must decide what test data are most appropriate for predicting risks to human health. 

The potential carcinogenicity of VX cannot be determined. Data are inadequate for performing a quantitative assessment of agent VX. The results of tests on bacteria, yeast and mammalian cell cultures (see Section 3.8) indicate that VX is not mutagenic or is only weakly mutagenic. These data provide supporting evidence that VX is not likely to be carcinogenic. 

Genotoxicity studies (micronucleus tests for chromosome aberrations) in mammalian polychromatic erythrocytes and nonhuman mammalian cell culture were positive. Ames Salmonella tests for mutagenicity have been negative. 

Short-term tests for mutagenicity, such as the Ames assay, and various mammalian cell culture assays, indicate that methoxyaldehyde may be mutagenic at high doses but methoxyethanol does not produce any positive response. Thirty-two millimole concentrations of methoxyethanol (but not equimolar concentrations of methoxyacetate) inhibited gap junction communication in cultures of rat myometrial myocytes. The failure of the end metabolite, methoxyacetate, and the relatively high concentrations required to produce a positive result led the authors to conclude that inhibition of gap junction communication was not likely as a mechanism of female reproductive toxicity. 

Genotoxicity tests were performed with senna fruit, senna leaf extract, sennosides, rhein, and aloe-emodin. Senna fruit, sennosides, and rhein did not increase mutation frequencies in the following test systems bacterial systems, mammalian cell culture tests, mouse lymphoma test, chromosome aberration test with Chinese hamster ovary (CHO) cells, bone marrow micronucleus test, chromosome aberration tests, and melanoblast cell test. With aloe-emodin, mutagenic effects were observed only in vitro in the chromosome aberration test with CHO cells and in the Salmonella reverse mutation test. In the in vitro gene mutation test with V79 cells, no mutagenic potential of aloe-emodin was observed. In vivo studies indicated no mutagenic activity of aloe-emodin, and aloe-emodin did not induce unscheduled DNA synthesis in an ex vivo assay performed with hepato-cytes of male rats (Heidemann et al. 1993). 

Mutagenic effect - tests on bacterial or mammalian cell cultures did not show mutagenic effects ... 

The in vitro cytogenetic assay is a short-term mutagenicity test for detecting chromosomal damage in cultured mammalian cells. 

Cole, J., Fox, M., Gamer, R.C., McGregor, D.B. and Thacker, J. (1990). Gene mutation assays in cultured mammalian cells. In UKEMS Subcommittee on Guidelines for Mutagenicity Testing. Report Part I rev. (Kirkland, D.J., Ed.). Cambridge University Press, pp. 87-114. 

Natarajan, A.T. and Obe, G. (1982). Mutagenicity testing with cultured mammalian cells cytogenetic assays. In Mutagenicity, New Horizons in Genetic Toxicology, (Heddle, J.A., Ed.). Academic Press, New York, pp. 172-213. 

Genotoxicity. 1,2-Dibromoethane has been tested for mutagenic activity in a battery of in vitro and in vivo assay systems. It is mutagenic in bacteria, fungi, fruit flies, and cultured mammalian cells (Ames andYanofasky 1971 Barber 1981 Brimeret al. 1982 Crespi etal. 1985 Moriya etal. 1983 ... 

Valeraldehyde caused chromosomal and DNA effects in mammalian cells in culture but was not mutagenic in an Ames bacterial test." ... 

Mutagenic potential—effects on genetic stability of bacteria (Ames test) of mammalian cells in culture... 

Ethylbenzene was non-mutagenic in bacteria, yeast and insects. In mammalian cells, it was inactive in inducing sister chromatid exchanges in Chinese hamster embryo cells but very weakly positive in cultured human l5miphocytes. It did not induce micronuclei in vivo, although it was positive in Syrian hamster embryo cells in vitro. It also caused cell transformation in these cells. Ethylbenzene induced mutations in the mouse lymphoma assay, but only at the highest non-lethal concentration tested. 

Bis(bromomethyl)propane-l,3-diol was mutagenic in only one of several bacterial strains tested, and only with metabolic activation. In cultured mammalian cells, it was only weakly active in tests for chromosomal aberrations and sister chromatid exchanges. Micronucleus formation, indicative of chromosomal damage, was induced in cells from mice exposed to 2,2-bis(bromomethyl)propane-l,3-diol in vivo. 

In assessing the potential for a chemical to produce heritable mutations in humans, it is necessary to examine the weight of evidence obtained from in vitro tests for mutations in microorganisms and cultured mammalian cells, from in vivo tests of mutations in animals, and from in vitro and in vivo tests for chromosome aberrations in mammalian cells. The strongest evidence would come from the demonstration that a chemical causes mutations or chromosome aberrations in human cells. As no studies were located that tested isophorone in cultured human cells or examined the cells of people with known exposure, this evidence is lacking. Of the five experiments that tested whether isophorone caused mutations or chromosome aberration in cultured mammalian cells, only two were positive a weak mutagenic response in mouse lymphoma cells and a positive test for sister... 

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