title: Determination of plasminogen activator inhibitor in plasma using t-PA and a chromogenic single-point poly-D-lysine stimulated assay.
abstract: A two stage method for determination of plasminogen activator inhibitor (PAI) activity in blood plasma is described. In the first stage, an excess of single-chain tissue plasminogen activator (t-PA) is added to plasma. In the second stage, the residual t-PA activity is determined with a plasminogen/chromogenic plasmin substrate assay utilizing poly-D-lysine as a t-PA stimulator. The method proved accurate since it correctly determined the PAI activity (range 0 to 110U/mL) in citrated plasma samples with levels established by time course analysis of t-PA inhibition and by titration with t-PA. Furthermore, correlation was excellent (r = 0.97) with the method of Chmielewska et al Thromb. Res. 31, 427-436, 1983. Plasma samples with increased platelet factor 4, indicative of platelet release, did not show increased levels of PAI activity.
mesh_terms: D001792:Blood Platelets / Q000378:metabolism; D002863:Chromogenic Compounds; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008545:Melanoma / Q000032:analysis; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors*; D015849:Plasminogen Inactivators; D011107:Polylysine; D013053:Spectrophotometry; D010959:Tissue Plasminogen Activator
chemical_list: D002863:Chromogenic Compounds; D006023:Glycoproteins; D015849:Plasminogen Inactivators; D011107:Polylysine; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator