Hoffman M, Monroe D M, Roberts H R
Duke University and Durham VA Medical Centers, The University of North Carolina, Chapel Hill, USA.
Haemostasis. 1996;26 Suppl 1:12-6. doi: 10.1159/000217233.
Coagulation reactions normally occur on cell membranes in vivo. Using a cell-based in vitro model system, we have shown that where a factor is located, not simply how much is activated, is critically important in determining its role in hemostasis. Factor Xa activated on a tissue factor (TF)-bearing cell is not equivalent to factor Xa activated on a platelet surface. Factor IX and factor VIII are required for hemostasis because they combine to generate factor Xa on the platelet surface. Factor X activation by factor VIIa/TF does not compensate for a lack of factor IX or VIII because the factor Xa activated by VIIa/TF is located on the wrong surface for efficient thrombin generation.
凝血反应通常在体内的细胞膜上发生。使用基于细胞的体外模型系统，我们已经表明，凝血因子的定位，而不仅仅是其激活的量，对于确定其在止血中的作用至关重要。在表达组织因子（TF）的细胞上激活的因子Xa与在血小板表面激活的因子Xa并不等同。止血需要因子IX和因子VIII，因为它们结合可在血小板表面生成因子Xa。因子VIIa/TF激活因子X并不能弥补因子IX或VIII的缺乏，因为VIIa/TF激活的因子Xa位于错误的表面，无法有效生成凝血酶。
