Lefkowitz J B, Monroe D M, Kasper C K, Roberts H R
Department of Pathology, University of Colorado Health Sciences Center, Denver.
Am J Hematol. 1993 Jul;43(3):177-82. doi: 10.1002/ajh.2830430304.
A subset of hemophilia B patients have a prolonged bovine-brain prothrombin time. These CRM+ patients are classified as having hemophilia Bm. The prolongation of the prothrombin time has been reported only with bovine brain (referred to as ox brain in some literature) as the source of thromboplastin; prothrombin times determined with thromboplastin from rabbit brain or human brain are not reported to be prolonged. Factor IX from a hemophilia Bm patient (factor IX Hilo) was isolated. The activity of factor IX Hilo was compared to that of normal factor IX in prothrombin time assays when the thromboplastin source was of bovine, rabbit, or human origin. Factor IX, either normal or Hilo, prolonged a prothrombin time regardless of the tissue factor source. However, unless thromboplastin was from a bovine source, this prolongation required high concentrations of factor IX. Further, factor IX normal was as effective as factor IX Hilo in prolonging the prothrombin time when rabbit or human thromboplastin was used. With bovine thromboplastin, factor IX Hilo was significantly better than factor IX normal at prolonging the prothrombin time. The amount of prolongation was dependent on the amount of factor IX Hilo added. In addition, the prolongation was dependent on the concentration of factor X present in the sample. The prothrombin time changed as much as 20 seconds when the factor X concentration was varied from 50% to 150% to normal (fixed concentration of factor IX Hilo). These results demonstrate the difficulty of classifying the severity of a hemophilia Bm patient based on the bovine brain prothrombin time unless both the factor IX and factor X concentrations are known.
一部分B型血友病患者的牛脑凝血酶原时间延长。这些CRM+患者被归类为患有Bm型血友病。凝血酶原时间延长仅在以牛脑（在一些文献中称为牛脑）作为凝血活酶来源时被报道；据报道，用兔脑或人脑的凝血活酶测定的凝血酶原时间并未延长。从一名Bm型血友病患者（因子IX希洛）中分离出因子IX。在凝血活酶来源为牛、兔或人的凝血酶原时间测定中，将因子IX希洛的活性与正常因子IX的活性进行了比较。正常或希洛的因子IX均可延长凝血酶原时间，而与组织因子来源无关。然而，除非凝血活酶来自牛源，否则这种延长需要高浓度的因子IX。此外，当使用兔或人凝血活酶时，正常因子IX在延长凝血酶原时间方面与因子IX希洛一样有效。使用牛凝血活酶时，因子IX希洛在延长凝血酶原时间方面明显优于正常因子IX。延长的程度取决于添加的因子IX希洛的量。此外，延长还取决于样品中存在的因子X的浓度。当因子X浓度从正常浓度的50%变化到150%（因子IX希洛浓度固定）时，凝血酶原时间变化多达二十秒。这些结果表明，除非同时知道因子IX和因子X的浓度，否则根据牛脑凝血酶原时间对Bm型血友病患者的严重程度进行分类是困难的。
