Continuous measurement of shear-induced platelet aggregation.

A mechanical device for continuous recording of shear-induced platelet aggregation (SIPA) has been developed using a turbidometric technique. The device consists of three components: light source, a thermostated cone-plate streaming chamber and optical detection unit. There was a good correlation between platelet count and transmitted light intensity under the conditions in which no activation of platelets occurred. When platelets were exposed to shear stress at 37 degrees C, transmitted light intensity increased with time. Scanning electronmicroscopic examinations revealed that more prominent platelet aggregation was demonstrated when light intensity increased. Reproducible recording of SIPA was obtained when experiments were repeated using the same sample. No change in light intensity was observed when formalin-fixed platelets were sheared. Both PGE1, and anti-GPIIb/IIIa mouse monoclonal antibody, AP2, showed complete inhibition of SIPA. It is indicated that our device for continuous measurement of SIPA is an important new tool to study one aspect of platelet functions.