[Temperature dependence of the sedimentation velocity of human erythrocytes]

The sedimentation velocity of yeast cells and human erythrocytes as a function of temperature was studied in a range from 6 degrees C to 40 degrees C. Whereas this function for yeast cells can be described by an exponential function the measurements with erythorcytes show minima at 10 degrees C and 20 degrees C, respectively, and maxima at 13 degrees C and 38 degrees C. Changes of the density or the shape of the cells cannot be the reason for these effects. Viscosity measurements on erythrocyte suspensions as a function of temperature also show deviations from the exponential function between 18 degrees C and 24 degrees C. The results explain that alterations of the membrane viscosity and phase transitions of the membrane lipids influence the sedimentation velocity of erythrocytes.