[Temperature, pH value, acid load and filtrability of normal human erythrocytes: in vitro studies--possible significance for hyperthermic hyperacidotic tumor therapy].

Normal human red blood cells, taken from healthy young men were separated from the other blood cells with the aid of a density centrifugation. The cells were titrated with acid to a defined minimal pH value and retitrated with sodium hydroxide to normal pH (7.4 +/- 0.1) two times. After each of the two acid loadings, which were done at 37 degrees C (normothermia) and 43 degrees C (hyperthermia) the so-called specific filtration time (FZsp) is determined with 5 microns Nuclepore membranes under 4% hematocrit. FZsp is a measure for the relative flow resistance of the red blood cells they have with the filtering membrane. FZsp was found to be irreversibly increased by the twofold acid load. The effect increases with decreasing pH and increasing temperature. Hydrochloric acid has a greater effect than lactic acid.