[Temperature denaturation of erythrocyte spectrin: rheology, deformability and resistance to detergents]

Detergent resistance of erythrocytes and viscosity of whole blood altered sharply already on the first stages of spectrin denaturation process (46-48 degrees C). Alternatively, deformability changes arise above 50 degrees C. Further insignificant increase in viscosity proceeded above 50 degrees C. Yield stress decreased to zero at t < 50 degrees C and at higher temperatures suspension demonstrated Newton's behavior. So, the following order of events can be seen: 1) the initial stages of denaturation process (46-48 degrees C) lead to shape modifications of erythrocytes (spicula formation on the cell rim-echinocytosis), with the detergent resistance of erythrocytes decreasing significantly and capability of echinocytes to aggregate with fibrinogen participation being lost. 2) Above 50 degrees C vesiculation and spherulation of erythrocytes lead to a sharp alteration of deformability with an insignificant increase of viscosity. Thus, deformability of erythrocytes, which is a very important factor in the capillary circulation, may be of lesser rheological role in large vessels.