The National Toxicology Program has undertaken a study to assess the ability of four genetic toxicology assays to predict the carcinogenicity of chemicals in 2-year rodent studies [Tennant et al.: Science 236:933-941, 1987]. Two of the assays, used for evaluating in vitro cytogenetic damage, were the SCE and chromosome aberration assays in Chinese hamster ovary cells. The results and data for 15 of the chemicals tested in these two assays are presented here. Each chemical was tested with and without exogenous metabolic activation. The chemicals tested were bisphenol A, 2-chloroethanol, C.I. acid orange 10, C.I. disperse yellow 3, C.I. solvent yellow 14, cytembena, D&C red 9, 1,2-dibromoethane, FD&C yellow 6, malaoxon, D,L-menthol, phenol, sulfisoxazole, titanium dioxide, and tris(2-ethylhexyl)phosphate. In vitro cytogenetic results from the other chemicals presented by Tennant et al. (Science 236:933-941, 1987) have been published by Galloway et al. (Environmental and Molecular Mutagenesis 10(Suppl 10): 1-175, 1987), Gulati et al. (Environmental and Molecular Mutagenesis 13:133-193, 1989), and Love-day et al. (Environmental Mutagenesis 13:60-94).

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Forty-six coded chemicals were tested for their ability to induce sister chromatid exchanges (SCEs) and chromosomal aberrations (ABs) in cultured Chinese hamster ovary (CHO) cells using a standard protocol with and without exogenous metabolic activation. Sixteen chemicals were negative and 15 were positive in both assays; 15 were positive for SCEs only (one chemical that was positive for SCEs was equivocal for ABs), and no chemicals induced ABs only. The effect of cell harvest time on the ability to detect the induction of ABs was examined for 18 chemicals. Seven chemicals produced a positive response using both standard and extended harvest times, five were positive only using an extended harvest time, and six were negative using both harvest times. The relationship between cell cycle delay and SCE induction was also examined, and the two appear to be unrelated.

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We report a spectrum of defects that were found in an 18-year-old girl who presented for investigation of primary amenorrhea. The patient was found to have Duane anomaly, left renal agenesis, absent uterus, bilateral sensorineural deafness, and bilateral preauricular skin tags and sinuses. Investigation of her family showed that her brother also had Duane anomaly, right renal agenesis, sensorineural deafness, and preauricular skin tags and that their father had preauricular skin tags. Cytogenetic analysis, including in situ hybridisation of peripheral blood lymphocytes, demonstrated a supernumerary bisatellited marker chromosome derived from the region of chromosome 22pter-q11 in the affected individuals. Our findings indicate that a gene or genes located in the region of chromosome 22pter-q11 may be associated with the Duane anomaly and the development of the urogenital tract.