Criteria for diagnosis of Glanzmann's thrombasthenia (GT) were normal PT, aPTT, platelet count, and morphology; no curve with ADP, epinephrine, or collagen; and normal curve with ristocetin
in platelet aggregation by lumiaggregometry.
GT is a rare autosomal recessive disorder characterized by mucocutaneous bleeding and absent or severely reduced platelet aggregation in response to the physiological agonists ADP, epinephrine, and collagen, but relatively normal aggregation in response to ristocetin
In general, most patients with vWD do not require prophylactic replacement therapy, especially for Type 1 disease or if the ristocetin
cofactor levels are more than 50% of normal.
In the assay plasma vWF binds to the platelet gp1b receptor on lyophilised reagent platelets and agglutinates the platelets in the presence of ristocetin
6mM fc), normal aggregation with a secondary wave to the 'weak' agonists ADP and epinephrine (respectively @ 5uM and 10uM fc), normal aggregation with the 'strong' agonist collagen (@ minimum of lug/ml fc) and normal aggregation to ristocetin
(@ between 1.
Type IIB von Willebrand factor with normal sialic acid content induces platelet aggregation in the absence of ristocetin
A STUDY ON CHIRAL RESOLUTION USING MIXTURES OF THE CHIRAL SELECTORS VANCOMYCIN AND RISTOCETIN
cofactor activity (VWF:RCo), collagen binding with type III VWF:CB, and multimer distribution were performed on all samples as previously described (11).
Results: Based on the von Willebrand factor antigen (vWF:Ag) and ristocetin
cofactor activity (vWF:RCo) levels and bleeding symptoms, vWD type-1 was diagnosed in 14 individuals (4 males, 10 females; prevalence: 1.
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Testing platelet response to the agonists ADP, Collagen, Epinephrine and Ristocetin
showed an increased response to low concentration Ristocetin
(Figure 1a) which is consistent with type 2B vWD (1).
For more than two decades, the ristocetin
cofactor (RCo) assay, which measures the vWF-mediated agglutination of platelets in the presence of the antibiotic ristocetin
, has been the most common method for measuring the functional activity of vWF.