STUDY OF PLATELET ADHESIVENESS AND AGGREGATION, WITH LATEX PARTICLES.

Abstract

Abstract The interaction of platelets and latex particles was studied as a means for measuring platelet adhesiveness. When platelet-rich plasma was exposed to a suspension of latex, platelet aggregation occurred. This could be quantitated with an automatic particle counter (Coulter). The count of single discrete platelets at the base-line threshold diminished following the addition of latex, while the count registered at higher thresholds increased in proportion to the platelet clumps formed. However, the use of EDTA as anticoagulant in place of trisodium citrate or the prior addition of adenosine monophosphate or of adenosine prevented platelet aggregation in the presence of latex particles. It was demonstrated that there was increased ADP in the ambient fluid following the addition of latex to the platelet-rich plasma sample. These observations suggest that latex particles induce platelet aggregation through release of ADP from the platelets and that this reaction is similar in many respects to what has been described for mixtures of platelets and collagen. Examination of platelet-rich plasma latex mixtures by electron microscopy showed the presence of latex particles in vacuoles within platelets. These findings indicate that not only do latex particles adhere to the platelets but that platelet phagocytosis of them occurs. This implies that the mechanisms in the platelet to surface reaction may be similar in many respects to those involved in phagocytosis.