The pH dependence of quantitative ristocetin-induced platelet aggregation: theoretical and practical implications-a new device for maintenance of platelet-rich plasma pH.
Quantitative ristocetin-induced platelet aggregation of normal platelet-rich plasma (PRP) decreased with time after PRP preparation. An increase in p H of the PRP with time proved to be responsible for this finding. Diffusion of CO2from the plasma is the prime determinant of the change in pH. Since a complex combination of factors influences CO2 diffusion (surface area-to-volume relationship, capping, mixing, etc.) The change in pH is variable with time. Thus, quantitative ristocetin aggregation should be pH controlled. A simple device for maintaining PRP pH constant by control of the ambient pCO2 was designed and found effective in keeping both pH and quantitative ristocetin aggregation constant over a prolonged period of time. It can be adapted for use in platelet aggregation studies employing other reagents. The pH dependence of ristocetin-induced platelet aggregation is consistent with other data supporting an elctrostatic interaction between the platelet, von Willebrand factor, and ristocetin. We favor a model wherein ristocetin neutralizes some of the platelet's negative change and permits the von Willebrand factor to bridge sites on separate platelets to induce agglutination.
D001780:Blood Coagulation Tests / Q000295:instrumentation; D001792:Blood Platelets; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D010949:Plasma / Q000502:physiology*; D010974:Platelet Aggregation / Q000187:drug effects; D012310:Ristocetin / Q000494:pharmacology; D013997:Time Factors
D012310:Ristocetin