[Changes in shape and plasticity of preserved erythrocytes]

The present study is concerned with alterations of erythrocyte shape and deformability during banking of ACD-AG blood samples. Highly diluted blood plasma suspensions of erythrocytes previously stored for 1 and 43 days, respectively, were employed for a) the microscopic evaluation of cell shapes, and b) measurement of the negative pressure pt essential for a cell's complete transit of a cylindrical micropipette 3.2 micrometers in diameter. Each of the blood samples was studied in an air equilibrated state either prior and following the fractionation of light and heavy cells. The classification of cell shapes was accomplished by a particular index. The findings are in accord with the banking related transformation of erythrocytes as known from recent studies. Although, exept of spheroechinocytes and spherocytes, a significant decline of deformability of stored red cells was found only in the case of discocytes and type 3 echinocytes, all types of heavy erythrocytes were shown less deformable in comparison with light cells equally banked for 43 days. The relation between our pt values and published data is discussed, and a crude estimate of the trapping time of the most rigid cells by the spleen after retransfusion is presented.