Thermohaemolysis of human erythrocytes in isotonic NaCl/sucrose media during transient heating

1. 1.|The hyperhermia induced haemolysis of cells and resealed ghosts suspended in isotonic NaCl/sucrose media was studied upon transient heating.

2. 2.|At 61.5°C a process of temperature accelerated disturbance of membrane permeability barrier was initiated, wich was sensed by the consequent volume changes. Concomitantly with this process the thermohaemolysis appeared as a threshold colloid-osmotic lysis.

3. 3.|The initial temperature of this successive barrier disturbance was decreased linearly by ethanol. At 18% ethanol this barrier disturbance took place at 39°C while spectrin was denaturated at about 45°C. Apparently, the spectrin denaturation was not sufficient, nor was involved in, the initiation of this membrane disturbance.

4. 4.|The membrane of cells made ion permeable in the presence of 18% ethanol by heating to 39°C contained irreversible pores with a radius of about 0.45 nm.

5. 5.|This suggests a conformational change of a protein(s) in their formation, but not spectrin nor the anion channel.

6. 6.|Using specific amino reagents it was ascertained, that a superficial NH₃⁺ group dissociable at neutral pH impeded this thermo-induced pore formation.

7. 7.|Consistent results show that this formation of membrane pores initiated at 61.5°C may be included in the still unknown mechanism of thermohaemolysis.