The present study was undertaken to provide more information on nuclear diameter in leukemic granulocytic early precursors myeloblasts. These cells represented by K562 myeloblasts originated from the blastic phase of the chronic myeloid leukaemia (CML) carry characteristic bcr-abl fusion gene. They represent a convenient model for in vitro studies of CML myeloblasts and are sensitive to various agents which may induce ageing, differentiation and cell death. Mean nuclear diameter (MNuD) and largest nuclear diameter (Mx NuD) in stained cytospins of these cells were measured at a high light microscopic magnification by means of computer programme. Starving cultures were used for induction of ageing without preceding differentiation, sodium butyrate was used as a cytostatic agent or differentiation inducer and imatinib mesylate represented a cytostatic agent for CML. The largest shift of MNuD to smaller values was noted in ageing cultures or cultures treated with butyrate. The decrease of MNuD was less apparent in resistant cells treated with imatinib. This drug, however, produced a very large incidence of necrotic or apoptotic cells or bodies. From the methodical point of view it should be mentioned that values of maximal nuclear diameter (MxNuD) followed similar trends as MNuD and thus provided similar information. The measurement of both nuclear diameters, i.e. MNuD and MxNuD might be a complementary and simple tool to evaluate the cell state in cytological preparations because of their decrease in ageing cells or cells treated with antiproliferative drugs of different mode of action.

Institute of Hematology and Blood Transfusion U nemocnice 1 Praha 2 128 20 Czech Republic