title: Inhibition of thrombin generation in recalcified plasma.
abstract: Eight inhibitors of thrombin generation were compared in recalcified unfrozen plasma. Individual or pooled normal citrated plasma was supplemented on polystyrol flat-bottom wells (23 degrees C) with increasing concentrations of low-molecular-weight heparin, heparin, danaparoid, fondaparinux, hirudin, argatroban, corn trypsin inhibitor, or aprotinin. Thrombin was generated by addition of 5 microl fresh 250 mmol/l CaCl2 to 50 microl plasma in polystyrol flat-bottom wells and incubation for 20 min at 37 degrees C (recalcified coagulation activity assay). Arginine stopped hemostasis activation and then the generated thrombin activity was specifically quantified. The approximate 50% inhibitory concentrations of plasmatic anticoagulants for individual or pooled normal plasma are, respectively, 0.6 or 3.7 mIU/ml low-molecular-weight heparin, 0.3 or 1.6 mIU/ml heparin, 0.7 or 6.1 mU/ml danaparoid, 0.023 or 0.18 microg/ml fondaparinux, 75 or 230 pg/ml hirudin, 0.026 or 0.24 microg/ml argatroban, 1 or 2 U/ml corn trypsin inhibitor, and 2 or 4 KIU/ml aprotinin. The 50% inhibitory concentration values for corn trypsin inhibitor or aprotinin at plasmatic concentrations above 4-100 U/ml might increase pathologically the thrombin generation. The recalcified coagulation activity assay is a sensitive method to measure prothrombotic tendencies of blood or subtle concentrations of any plasmatic anticoagulant. It is suggested to analyze the individual patient's sensibility to certain plasmatic anticoagulants.
authors.affiliation: Department of Clinical Chemistry, University Hospital, Giessen, Germany. thstief@med.uni-marburg.de
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Stief
mesh_terms: D000925:Anticoagulants / Q000494:pharmacology*; D007611:Aprotinin / Q000494:pharmacology; D001120:Arginine / Q000031:analogs & derivatives; D001780:Blood Coagulation Tests / Q000379:methods*; D002809:Chondroitin Sulfates / Q000494:pharmacology; D003871:Dermatan Sulfate / Q000494:pharmacology; D000077425:Fondaparinux; D006493:Heparin / Q000494:pharmacology; D006497:Heparan Sulfate / Q000494:pharmacology; D006629:Hirudins / Q000494:pharmacology; D006801:Humans; D010875:Pipecolic Acids / Q000494:pharmacology; D010940:Plant Proteins / Q000494:pharmacology; D010949:Plasma / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology*; D011134:Polysaccharides / Q000494:pharmacology; D013449:Sulfonamides; D013917:Thrombin / Q000032:analysis / Q000502:physiology
chemical_list: D000925:Anticoagulants; D007611:Aprotinin; D001120:Arginine; D002809:Chondroitin Sulfates; D003871:Dermatan Sulfate; D000077425:Fondaparinux; D006493:Heparin; D006497:Heparan Sulfate; D006629:Hirudins; D010875:Pipecolic Acids; D010940:Plant Proteins; D011134:Polysaccharides; D013449:Sulfonamides; D013917:Thrombin; C052160:trypsin inhibitor, Zea mays; C035838:danaparoid; C031942:argatroban