[The relation of the phenomenon of nuclear achromasia to cell activation for proliferation].

As it has been shown earlier, the cells of experimental tumours as well as some normal cells of the thymus, spleen and testes show the phenomenon of nuclear achromasia (low affinity for ionic dyes) in cytological preparations. Possible connection between the phenomenon and activation for proliferation was the subject of the study presented. A reliable increase in the number of cells displaying the nuclear achromasia when staining with methylene blue after treatment with phytohaemagglutinin for 30 min as well as appearance of such cells in rat liver regenerates 1 h after partial hepatectomy was substantiated to be a result of the cell activation as tested by the enhanced acridine orange intercalation into their DNA.