Influence of hyperthermia and acidosis on the altered red blood cell osmotic fragility in mice with Ehrlich ascites tumor.

Advanced cancer affects many body functions including red cell production and survival. The resulting anemia is probably due to membrane alterations. Red cells of Ehrlich ascites tumor (EAT)-bearing mice (EAT-RC) are known to be osmotically more stable than those of normal animals (N-RC). We extended the hemolytic studies made previously by others to various combinations of temperature and pH and tested the influence of glucose. In the absence of glucose, both red cell types are most resistant to hemolysis at 37 degrees C and pH 7.4; lowering pH renders the cells more labile. However, at every condition chosen, the extent of hemolysis was for EAT-RC in general significantly smaller. This greater osmotic stability was dramatically increased at pH 6.2 in the presence of glucose, whereas N-RC remained almost unaffected. The remarkable difference in osmotic stability between red cells from normal animals and from those with tumor might possibly be of prognostic value; moreover, it has therapeutic consequences when regimens are envisaged whose effector mechanisms are based on hyperthermia, tumor acidification, and microcirculation inhibition.