Platelet freeze-storage for antibody testing.
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Biomedical subjects
Publications and source records attributed to H R Gralnick.
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The Factor VIII/von Willebrand factor protein was characterized in two unrelated patients with von Willebrand's disease in whom procoagulant and Factor VIII/von Willebrand factor antigen levels were normal. In both patients evidence of an abnormal protein was observed on crossed antigen-antibody electrophoresis. In one patient the Factor VIII/von Willebrand factor protein eluted from Sepharose 4B in a position and distribution identical to normal with normal levels of procoagulant activity and antigen. However, the partially purified Factor VIII/von Willebrand factor protein had markedly reduced von Willebrand factor activity in a ristocetin assay. In the second patient the peak of Factor VIII/von Willebrand factor protein, antigen, and procoagulant activity eluted from a Sepharose 4B column with an estimated molecular weight of approximately half that of normal. This protein had no von Willebrand factor activity. In both patients the reduced Factor VIII/von Willebrand factor protein subunit was indistinguishable from normal on polyacrylamide gel electrophoresis. These studies indicate that in some patients with von Willebrand's disease there is a qualitative defect of the Factor VII/von Willebrand factor protein; the total amount of protein, antigen, and procoagulant activity are normal while the von Willebrand factor activity is deficient.
The purified factor VIII-related protein we have previously characterized from normal cryoprecipitate possesses both procoagulant activity and vWf activity. We have attempted to isolate and characterize this protein from three patients with severe vWd. This protein is absent or markedly diminished in amount in these vWd patients, as judged by gel filtration, polyacrylamide-gel electrophoresis, and immunoprecipitation assays. Likewise, the procoagulant and vWf activities are deficient. As vWf activity is one of the major biologic functions of either the normal or hemophilic factor VIII-related protein, the purified protein should be designated the f VIII/vWf protein.
Profound thrombocytopenia developed in a patient during treatment with heparin for venous thrombosis. The platelet count increased toward normal when heparin administration was stopped, but fell abruptly when the drug was again given. Platelet aggregation occurred when heparin was added to the patient's platelet-rich plasma, or to normal platelets plus the patient's serum. This serum also effected release of 3H-serotonin from normal platelets. This pattern of aggregation was clearly different from that occasionally caused by heparin in a control population. The data is consistent with an effect of heparin on platelets, possibly mediated by on immune mechanism.
A bleeding diathesis is described which is phenotypically indistinguishable from hemophilia A and which has been transmitted as a dominant trait in three generations of women in a North Carolina kindred. The abnormal phenotype is characterized by clinical mildness and slightly abnormal clotting time, prothrombin consumption, and partial thromboplastin time. Bleeding time, platelet count, clot retraction, tourniquet test, and prothrombin time are normal. Concentration of factors I, II, V, VII, IX, X, and XII are normal, while factor VIII activity is reduced to 2%-5% of control values. De novo synthesis of factor VIII does not occur after transfusion; factor VIII-related antigen is normal; patients' plasmas aggregate platelets normally in the presence of ristocetin, and a typical protein pattern is seen when a chymotryptic digest of cryoprecipitate of the proband is examined by SDS-polyacrylamide gel electrophoresis. Six possible genetic explanations are entertained. Balanced X-autosomal translocation of hemophilia A heterozygotes has been excluded by cytogenetic analysis of metaphase chromosomes. Classes von Willebrand's disease (vWd) is probably excluded on the basis of the laboratory data, and extreme lyonization of hemophilia A heterozygotes on probabilistic grounds. The genetic possibilities which cannot be excluded include a previously unrecognized variant mutation at the vWd locus, a dominant mutation at the hemophilia A locus on the X chromosome, and dominant mutation at a hypothetical fourth locus involved in factor VIII synthesis and control.
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