Compression of Human Red Cells during Centrifuging

Abstract

THE question as to whether the mammalian red coll is or is not a ‘perfect osmometer’ in hypotonic media has been sufficiently discussed^1,2, the perfection of the osmometer being measured in terms of the value of a constant R. The red cells of heparinized blood are usually very good osmometers (R = 0.95–1.0) (refs. 3 and 4), and those of oxalated blood are poor osmometers (R = 0.5–0.8); the value of R} however, depends on the details of the methods used to measure it. Several explanations for the value of R being less than 0.95–1.0 have been suggested, for example, that some of the water in the red cell is bound, that electrolytes escape into hypotonic media, and that crenated or paracrystalline red cells have a real bulk modulus, It has also been suggested that red cells are compressed during high-speed centrifuging⁵, the extent of the compression increasing as the quantity of water in the cell increases, and that compression of the cells accounts for values of R less than 0.9–1.0.