[The tissue survival problem in using current methods of morphological study]

Time course of ultrastructural changes and RNA production in human brain and myocardial cells during the period between clinical and biological death is studied. Changes in the cytoplasm of brain neurons develop 4 hours after death, and 8 h post mortem the destructive changes in the cytoplasm and nuclei progress. During the period of 4-13 h post mortem the endotheliocyte nuclei are capable of producing RNA. Active production of RNA is on-going in the myocyte nuclei 4 h after death; the synthetic activity decreases by 8 h and by 13 h the synthetic activity in autopsy material is over.