[Use of hydroxyethyl starch as a cryoprotective medium during platelet storage at low temperatures]

The effects of HES and HES + DMSO used as cryoprotective media for storage of human platelets in liquid nitrogen and vapor phase of liquid nitrogen were studied. Solution of 6% and 15% HES with molecular weight ranging from 65,000 to 250,000, and 10% DMSO were used. The criteria accepted for evaluation of the efficiency of these cryoprotective media were: 1. platelet counts, 2. participation of platelets in the processes of hemostasis measured in vitro by the ability of platelets to release adenine nucleotides (ATP + ADP) after thrombin stimulation. It was found that 15% HES is a more effective cryoprotective medium than 6% HES. The use of 15% HES + 10% DMSO gave similar results as the use of 10% DMSO alone.