title: The antiheparin effect of alpha 1-acid glycoprotein, evaluated by the activated partial thromboplastin time and by a factor Xa assay for heparin.
abstract: The heparin-antagonizing effect of human alpha 1-acid glycoprotein (alpha 1-acid GP) was studied by activated partial thromboplastin time (APTT) and by a factor Xa assay for heparin using a chromogenic substrate for factor Xa. The antiheparin effect of alpha 1-acid GP in the APTT system was similar to the effect on heparin thrombin clotting time (HTCT), and the effect in the factor Xa assay system corresponded well with the effect in a heparin cofactor assay system using chromogenic substrate for thrombin instead of factor Xa. It is concluded that alpha 1-acid GP contributes to the reduced anticoagulant effect of heparin observed in various acute stages of disease, when assayed not only by HTCT but also by so-called 'global' coagulation tests, such as the activated partial thromboplastin time.
mesh_terms: D000991:Antithrombins / Q000378:metabolism; D001777:Blood Coagulation / Q000187:drug effects*; D005170:Factor X / Q000378:metabolism; D006023:Glycoproteins / Q000494:pharmacology*; D006493:Heparin / Q000378:metabolism; D006494:Heparin Antagonists; D006801:Humans; D010314:Partial Thromboplastin Time
chemical_list: D000991:Antithrombins; D006023:Glycoproteins; D006494:Heparin Antagonists; D005170:Factor X; D006493:Heparin