Hyperthermic induction of premature chromosome condensation in human lymphocytes.

Hyperthermic induction of chromosomal aberrations was examined in human lymphocytes. For this purpose, whole blood cultures were exposed to an elevated temperature (43 degrees C) at the 46th h of culture initiation, followed by 24 h of recovery. Detailed chromosomal analysis showed significantly higher levels of aberrations as compared to control cultures of the same individuals. These aberrations include breaks, gaps of both chromosome and chromatid type, aneuploidy and high levels of polyploidy. The interesting observation was the occurrence of S-phase premature chromosome condensation (PCC). The S-phase PCC observed here could be due to asynchronous nuclei induced by hyperthermia. A possible interpretation for the occurrence of asynchronous nuclei leading to the induction of S-phase PCC is discussed.