Evaluation of hydroquinone and chloral hydrate on the in vitro micronucleus test on isolated lymphocytes

The cytochalasin B micronucleus test was performed in human peripheral lymphocyte cultures to assay the ability of hydroquinone and chloral hydrate to induce micronuclei, in the presence or absence of an exogenous metabolic activation system. Cultures and readings were performed in duplicate. No significant damage was found after treatment with chloral hydrate in this test system, whereas hydroquinone induced a clear positive response in one culture in the presence of metabolic activation during the G1 phase. Isolated lymphocytes used as a test system provide information about the test compound itself without interference by blood components. Comparison of the two readers' data showed few marked discrepancies in the number of micronuclei recorded in binucleated cells. Strict criteria for data analysis are therefore necessary to avoid intra-assay or operator variability.