The effects of alcohols, procaine and hyperthermia on the protein content of nuclei and chromatin.

Since previous studies suggest that heat-induced nuclear changes correlate with cell killing we have extended these observations by measuring nuclear and chromatin protein content in HeLa cells heat sensitized by agents which are believed to cause membrane damage. Specifically, we have investigated the effects of alcohol (C2-C5) and procaine. Exposure of HeLa cells to alcohol concentrations greater than 1 M ethanol or 0.2 M butanol for 30 min causes a measurable increase in the protein content of both nuclei and chromatin. When cells were heated (45 degrees C) in the presence of alcohol, the increase in nuclear and chromatin protein content was significantly greater than that for heat alone at concentrations above 0.25 M ethanol and 0.07 M butanol. In addition, the presence of 0.41 M ethanol causes a two-fold increase, over heat alone, in the amount of protein absorbed to chromatin when cells are heated at 45 degrees C from 0 to 60 min. Similar effects were observed with procaine. Thus, alcohol or procaine alone can cause an increase in chromatin protein content and can act synergistically with heat to cause a larger increase. These results suggest that membrane damage may cause a larger increased protein content of chromatin and thereby lead to cell death.