C-MITOSIS AND NUMERICAL CHROMOSOME ABERRATION ANALYSES IN HUMAN-LYMPHOCYTES - 10 KNOWN OR SUSPECTED SPINDLE POISONS

As a part of a coordinated EEC project to validate suitable assays for chemically induced genomic mutations, numerical chromosomal aberratio ns and spindle effects were studied in human lymphocyte cultures expos ed to cadmium chloride, chloral hydrate, colchicine, diazepam, econazo le, hydroquinone, pyrimethamine, thiabendazole, thimerosal and vinblas tine. Chromosome number analysis was carried out after treatment for 4 8 and 72 h; spindle effects, i.e., increases in the mitotic indices an d c-mitoses, were analyzed in cultures treated 5 h before fixation. Do se-related numerical chromosomal aberrations are induced by colchicine and vinblastine, the only chemicals that also induce c-mitotic effect s in a wide range of doses. Hyperdiploidy is induced by chloral hydrat e, cadmium chloride and thimerosal without dose-effect relationship; c hloral hydrate and thimerosal affect spindle functions while only a we ak spindle effect is produced by cadmium chloride. Tetraploid and/or e ndoreduplicated cells are induced without dose-effect relationship by hydroquinone, thiabendazole and thimerosal, all of them able to produc e c-mitotic effects. Diazepam and econazole induce only hypodiploidy; pyrimethamine does not induce numerical chromosomal aberrations.