Two Types of Interphase Death of Lymphocytes Exposed to Temperatures of 37-45°C

Publisher Website
Google Scholar
Abstract
Normal human blood lymphocytes in RPMI 1640 media with 20% human serum (pH 7.6) were exposed to temperatures of 37.degree.-45.degree. C. The processes of cell death were studied by phase contrast and EM, by time-lapse cinemicrography, and by serial counts of viable and dead cells. Dead cells showed 2 distinctive morphologic types: cells with pyknotic nuclei and condensed cells. Examination by phase microscopy revealed that dead cells with pyknotic nuclei had uniformly dark nuclei which were either ring-shaped, crescentic or round; a moderate amount of clear cytoplasm; and a thin plasma membrane. When examined by EM, the pyknotic nucleus was seen as a homogenous mass of electron-dense granules without a normal architectural pattern or nuclear membrane. EM showed the condensed cell characterized by electron-opaque cytoplasm, a dense nucleus with normal architectural features, and multiple cytoplasmic vacuoles. Serial counts of viable and dead cells showed that exposure of lymphocytes to 43.degree. or 45.degree. C killed cells primarily by the process resulting in condensed cells; at 37.degree., 41.degree. and 42.degree. C, lymphocytes died primarily by pyknosis. The hypothesis that different mechanisms killed the cells above and below the critical temperature of 43.degree. C is supported. [This study has applicability to cancer therapy.].