Preliminary studies on scoring micronuclei by computerised image analysis.

Initial studies of the use of computerised image analysis to determine micronucleus frequencies in human lymphocytes that have completed one nuclear division are described. Two methods, based on (a) bromodeoxyuridine incorporation and (b) cytokinesis blocking with cytochalasin-B, were studied. The former method is directly amenable to automation. Cytokinesis-blocked cells could not be automatically recognised by image analysis but it was possible to obtain the correct micronucleus frequency from the integrated optical density histograms by using the mononucleate/binucleate cell ratio obtained by visual analysis. The mean (+/- 1 S.E.) integrated optical density of X-ray-induced micronuclei was 11.2% (+/- 1.1) of that measured for nuclei of G1 cells.