Platelets Cross-Linked with Dimethyl Adipimidate Hydrochloride (DMA) Used in Ristocetin Assay For F VIII: Rcof.

Abstract

When PRP or washed platelets are incubated with dimethyl adipimidate (DMA)(final concentration 2 mg/ml, 30 - 60 min.), the aggregation of the platelets by ADP, collagen or thrombin is clearly reduced. Aggregation by ristocetin plus F VIII: Rcof is however not affected.DMA is a bifunctional imidoester which acts as a cross-linking reagent. SDS Polyacrylamide gel electrophoresis of platelet membranes shows a different pattern for membrane glycoproteins from the platelet treated with DMA when compared to untreated platelets. This different pattern is due to cross-linking of the glycoproteins.The DMA - treated platelets can be stored for at least three weeks at 4° without losing their ability to aggregate in the ristocetin F VIII: Rcof test system. Both freshly -treated and stored DMA - treated platelets could be used to assay F VIII: Rcof reproducible in normal pooled plasma and in defective plasma (von Willebrand’s disease patients; N = 8). The preparation of DMA-fixed platelets takes less than two hours.