[Ultrastructural aspects of preglioma].

Investigation of submicroscopic changes in the astrocytes after the intracerebral injection of the carcinogen 9,10-dimethyl-1-2-benzanthracene suggested that the so-called substantial period of preglioma began from the 45th day of the experiment, when structurally atypical astrocytes appeared against the background of distrophic changes. The changes in the submicroscopic organization of the astrocytes during chemical carcinogenesis can be divided into three stages: 1) intracellular hyperplasia due to traumatic injury of the brain; 2) dystrophic changes connected with the vascular tissue disturbances and immediate action of the carcinogen on the tissue; 3) atypical ultrastructure reconstruction of the astrocytes.