A Study of the Osmotic Behavior of the Human Erythrocyte*†

Abstract

Despite many previous studies of the osmotic properties of erythrocytes, unequivocal answers have not been given to two important questions: 1) Is the erythrocyte in osmotic equilibrium with its normal surrounding fluid? 2) When the osmotic properties of the surrounding fluid are varied, does the erythrocyte gain or lose water to the extent necessary to remain in osmotic equilibrium with the new surroundings-that is, does the erythrocyte behave as a perfect osmometer over a wide range?Previous work related to these questions has been of two general types: measurements of changes of volume of the erythrocytes as the osmotic concentration of the extracellular phase was altered; and measurements of one or more of the colligative properties of the solutions involved. The present study is of the latter type. The osmotic behavior of the normal human erythrocyte has been investigated over a wide range of concentrations by a cryoscopic method and a method for measuring the melting point of microscopic samples. The results give affirmative answers to both of the above questions and illustrate some of the difficulties which may be expected in studies of osmotic properties of any tissues.

The osmotic response of human erythrocytes and the membrane cytoskeleton

“…Again, it is possible that the heating, like diamide treatment, dissociates the spectrinactin network from the rest of the membrane. The finding that if isolated spectrin in vitro is incubated at temperatures above 40°C it will no longer bind to the ghost membrane (Williams et al, 1959) also appears to support this possibility.…”

Osmotic fragility of drug carrier erythrocytes

“…Many studies have demonstrated the relationship between altered osmotic fragility and abnormal geometry of erythrocytes [1,11,21]. Elevated osmotic fragility, however, is not only important with respect to a long life-span of erythrocyte carriers and the encapsulated drugs, but also with respect to an uncontrolled breakdown of loaded cells in vitro and a reduced shelf-life.…”

Posthypertonic Hemolysis in Sodium Chloride Systems

“…As Soderstrom outlined his theory rather briefly, it will be considered in more detail here. The normal red cell can attain osmotic equilibrium with its environment over a fairly wide concentration range (Williams et al 1959). In this case the rapid water exchange (Sidel and Solomon 1957) quickly reduces any solute gradient which might act as a driving force for net solute movements.…”