title: Assay of dermatan sulfate cofactor (heparin cofactor II) activity in human plasma.
abstract: An assay measuring the thrombin inactivating effect of human plasma in the presence of dermatan sulfate (DS) is described. Test plasma, diluted 1/50, is incubated with human thrombin in the presence of DS. Remaining thrombin is determined with chromogenic substrate 2AcOH . H-D-CHG-Ala-Arg-pNA. Three dilutions of reference plasma suffice and the standard curve is linear. Antithrombin III (AT) exerts a small (3-8%) effect in the assay. When test plasma contains heparin above 0.05 U/ml, this unspecific effect of AT increases, but it may be abolished by antibodies against AT. In a normal material (n = 50), the SD of DS cofactor activity was greater (15%) than that of AT (8.7%). DS cofactor was normal in hereditary AT deficiency and in 15 patients with deep venous thrombosis. In liver cirrhosis and in DIC, both inhibitors were markedly depressed, to similar degrees (r = 0.84).
mesh_terms: D020152:Antithrombin III Deficiency; D000991:Antithrombins / Q000032:analysis*; D002863:Chromogenic Compounds; D003871:Dermatan Sulfate / Q000097:blood; D004211:Disseminated Intravascular Coagulation / Q000097:blood; D006023:Glycoproteins / Q000097:blood*; D015844:Heparin Cofactor II; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood; D009842:Oligopeptides; D013917:Thrombin / Q000032:analysis*; D013924:Thrombophlebitis / Q000097:blood
chemical_list: D000991:Antithrombins; D002863:Chromogenic Compounds; D006023:Glycoproteins; D009842:Oligopeptides; C042443:cyclohexylglycyl-alanyl-arginine-4-nitroanilide; D003871:Dermatan Sulfate; D015844:Heparin Cofactor II; D013917:Thrombin