title: High and low affinity heparin compared with unfractionated heparin as antithrombotic drugs.
abstract: A preparation of heparin was separated by affinity chromatography into two fractions: one of high ( HAH ) and the other of low (LAH) affinity to antithrombin III. These two fractions were compared with unfractionated heparin ( UFH ) by in vitro assay and their ability to impair experimental stasis thrombosis was also examined. Although the in vitro activity of HAH was double that of UFH , HAH was less effective than UFH as an antithrombotic drug; LAH was virtually inactive, both in vitro and in vivo. A mixture of 30 micrograms/kg of HAH and 50 micrograms/kg of LAH was as effective in preventing thrombosis as 80 micrograms/kg of UFH , and was more effective than 40 micrograms/kg of HAH alone, demonstrating that LAH potentiates the action of HAH in vivo.
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects*; D002846:Chromatography, Affinity / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D006493:Heparin / Q000032:analysis* / Q000494:pharmacology; D006801:Humans; D010314:Partial Thromboplastin Time; D011817:Rabbits; D013927:Thrombosis / Q000517:prevention & control
chemical_list: D006493:Heparin