Karyolysis

KARYOLYSIS, karyolysis (from Greek karyon - nucleus and lysis - dissolution), a change in cell nuclei characterized by their apparent dissolution. This change indicates a necrobiotic state of cells transitioning into their death. The structural change observed in the nucleus consists of a peculiar alteration of the chromatin, which Flemming called chromatolysis (see illustration): the division into basichromatin and oxychromatin disappears; the chromatin is distributed diffusely in the nucleus, hiding its structure; vacuoles often appear in such a nucleus. Finally, the entire substance of the nucleus begins to be weakly stained by nuclear dyes and disappears. K. accompanies tissue necrosis, for example, in infarcts, in tubercles, in blood leukocytes (leukolysis). Vasilievsky induced chromatolysis in the nuclei of germ cells by injecting turpentine. As a physiological phenomenon, K. is observed in the desquamating horny scales of the epidermis, in the so-called intermediate bodies (corps residues!) and others.