American journal of hematology
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Clinical Trial
Safety and efficacy of purified factor IX concentrate and antifibrinolytic agents for dental extractions in hemophilia B.
This study evaluated the safety and efficacy of combined treatment with epsilon-aminocaproic acid or tranexamic acid and monoclonal antibody purified factor IX (MAb factor IX) for prophylaxis against bleeding in eight hemophilia B patients undergoing nine dental extraction procedures. All patients achieved excellent hemostasis without clinical evidence of thrombosis. There were no significant changes in hemoglobin or hematocrit or in markers of hemostatic system activation (prothrombin fragment F1+2, fibrinopeptide A, and fragment B beta 15-42) after surgery. Thus, a highly purified factor IX concentrate and antifibrinolytic therapy can be effectively and safely combined in hemophilia B patients undergoing dental extractions.
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In order to harmonize the prothrombin time (PT) reporting systems, the World Health Organization, in collaboration with the International Committee on Thrombosis and Hemostasis, and the International Council on the Standardization in Hematology proposed a reporting system, the so-called international normalized ratio (INR). As the calculation of the INR depends on mathematical formula requiring a special calculator or mathematic tables, its derivation is associated with some difficulties and errors. In this article a nomogram is presented, by which derivation of the INR from different PT reporting methods can be easily done within a few seconds.
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Comparative Study
Coagulant proteins and thrombin generation in synovial fluid: a model for extravascular coagulation.
The coagulant content and thrombin generating potential of synovial fluid from patients with osteoarthritis were studied as a model of extravascular coagulation. The concentrations of individual coagulant proteins were partially correlated with their molecular weight. The levels of the very large coagulants factor V, factor VIII and von Willebrand factor antigen (vWF:ag) are less than 1% of the activities found in a normal pooled reference plasma while smaller coagulants including factors IX, XI and prothrombin range between 9 and 30%. ⋯ The addition of specific antibodies to factor VIII or factor V strongly inhibited thrombin production by aPTT. These data confirm a roughly inverse relationship between the concentrations of coagulation proteins and their molecular weight in synovial fluid and indicate that thrombin can be generated in synovial fluid. The inactivation of thrombin in synovial fluid may be more dependent on antithrombin-III than in plasma because of the increased AT-III/alpha-2 macroglobulin ratio seen in synovial fluid.
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In clinical practice, occasionally some patients show dissociated values of fibrinogen/fibrin degradation products (FDP) and D-dimer (cross-linked fibrin degradation products). In an attempt to assess the frequency, clinical backgrounds, and hemostatic states of these cases, FDP and D-dimer were simultaneously measured together with other hemostatic parameters in 371 samples from patients with various diseases. As a whole, FDP were elevated in parallel with the progress of activation of blood coagulation and fibrinolysis. ⋯ In the dissociated group, activation of coagulation and fibrinolysis occurred to a lesser extent than others. Analysis of these samples suggested that the possible reasons for the dissociation between FDP and D-dimer values were accelerated fibrinogenolysis with or without secondary fibrinolysis, accelerated fibrinogenolysis by non-plasmic proteinases, elevated soluble fibrin, and possibly false-positive FDP levels due to unclottable fibrinogen remaining in the serum samples. In practice, simultaneous measurements of FDP and D-dimer are useful for more accurate estimation of hyperfibrinolytic states.