Physical Properties of Red Cells as Related to Effects in Vivo. II. Effect of Thermal Treatment on Rigidity of Red Cells, Stroma and the Sickle Cell

Heating of human or dog red cells at 49 C. for 15 minutes or 60 minutes increased resistance to packing by a centrifugal force, increased viscosity and deformed them. After 15 minutes of heating, osmotic fragility was usually normal but was elevated after 60 minutes with the formation of spheroidal cells.

The increase in viscosity caused by heating red cells at 49 C. for 60 minutes did not appear to result from the effect of heat on the hemoglobin or the hemolysis products of red cells disrupted by sonic treatment. The heating of intact human or dog red cell stroma in serum, or stroma washed multiple times in physiologic saline however, regularly increased their viscosity and produced buds and microstroma. The rigidity of stroma was increased by heating, probably accounting for the increased viscosity of heated intact red cells.

The rigidity of heated stroma of red cells was further demonstrated by showing that the shape changes of the sickling process could be prevented in large part by the heating of sickle cells. Heating did not, however, prevent tactoid formation in stroma-free sickle-cell hemoglobin solutions.