Figure 4

Nonlinear course of temperature-induced platelet activation. Figure 4 shows the change of the mean hydrodynamic radius R_H as a function of temperature. R_H is calculated from the results of dynamic light scattering measurements and is a parameter indicative for the average platelet morphology. Minor changes occur between 37° C and 30° C, whereas the R_H increases significantly when the platelets are cooled below 30° C. R_H increases because activated platelets extend numerous pseudopodia that decrease their Brownian motion (for details see Appendix).