title: Degree of chromatin fragmentation and frequency of nuclear pyknosis in Percoll-fractionated thymocytes of irradiated rats.
abstract: The relationship between nuclear chromatin degradation to polydeoxyribonucleotides (PDN) and other features of interphase death were studied using thymocytes of normal and X-irradiated rats. Fractionation of the thymic cells in Percoll gradients was performed in order to separate dead from intact cells. The degree of radiation-induced chromatin fragmentation, as assessed by electrophoresis, was similar for PDN from all Percoll bands. Following irradiation 87-98 per cent of 'heavy' thymocytes were pyknotic and almost devoid of receptors to autologous erythrocytes thus comprising a dead cell population. A direct relationship between PDN content and nuclear pyknosis was noted throughout the gradient. The loss of autologous rosette-forming ability was directly related to other indices of interphase death. The possibility of PDN originating from pyknosis-prone cells and the capacity of radiosensitive thymocytes to form autologous rosettes are discussed.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000473:pathology / Q000528:radiation effects; D002469:Cell Separation; D002843:Chromatin / Q000473:pathology / Q000528:radiation effects; D004249:DNA Damage; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism; D012397:Rosette Formation; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D002843:Chromatin; D011956:Receptors, Cell Surface