CHANGES IN SMALL-ANGLE LIGHT-SCATTERING B Y PLATELETS DURING THEIR ACTIVATION AND AGGREGATION

Small-angle light scattering (0,5-7 degrees) by platelets is enhanced upon the adenosine-5'-diphosphate-induced formation of microaggregates of platelets. The intensity of the scattered Light, measured within a short: period of time after stimulation of platelets, may by used as a nephelometric quantitative index of their initial aggregation, The l ight transmittance of platelet suspensions decreases after stimulation due to both the rounding of cell body and the initial aggregation of cells. Sodium hypochlorite at concentrations corresponding to its cont ent in tap water inhibits the Ca2+-induced aggregation of isolated rab bit: platelets. The tap water causes the transition of platelets to a state that is refractory with respect to CaCl2.