Platelet aggregation by laminar shear and Brownian motion

Abstract

Rates of platelet aggregation in citrated PRP were measured under conditions of a well-defined Couette shear flow at 25°C. Smoluchowski's coagulation theories for Brownian motion and for simultaneous Brownian and shear motion were combined with the Rayleigh-Gans theory of light scattering to measure Brownian and shear collision efficiency factors for systems of aggregating platelets. This approach permits a considerably more systematic and readily interpretable data base for analyzing normal and abnormal platelet aggregation phenomena than was heretofore possible. This technique was also used to investigate the effects of varying ADP and PGE1 concentrations on platelet aggregation rates. Slight enhancement of platelet aggregation was observed in PRP suspensions in which red cell ghosts were added.