van Zutphen H, Bevers E M, Hemker H C, Zwaal R F
Br J Haematol. 1980 May;45(1):121-31. doi: 10.1111/j.1365-2141.1980.tb03817.x.
The procoagulant activity obtained from bovine thrombocytes has been compared to that of lipids isolated from platelets, with and without the addition of purified bovine factor V. A one-stage assay, which consisted of delipidated bovine plasma containing RVV-activated factor X, was used to assess the activity. At low lipid concentrations no difference in coagulant activity was found between sonicated vesicles of extracted platelet lipid and lysed platelets. At higher lipid concentrations, however, the extracted lipids were found to be less active than lysed platelets. Determination of factor V in suspensions of gel-filtered platelets demonstrated that suspensions containing 2 X 10(9) platelets per ml possessed about 1% of the factor V activity present in a normal bovine plasma pool. Platelet lysis by sonication produced a five-fold increase in factor V activity. Addition of factor V to sonicated vesicles of extracted platelet lipid, so as to produce an identical factor V activity per amount of lipid as found in lysed platelets, decreased the clotting time only in the higher lipid concentration range. A further three-fold increase in the amount of factor V added to the lipid vesicles made the coagulant properties of the lipid vesicles indistinguishable from those of lysed platelets over the whole range of phospholipid concentrations tested. When the conditions of the test were changed by diminishing the concentration of factor Xa in the substrate plasma, the difference between lysed platelets and extracted platelet lipid disappeared completely. It is concluded that the higher coagulant activity of lysed platelets, as compared to that of extracted platelet lipid, can be ascribed to platelet factor V activity. Therefore there is no compelling necessity to postulate the existence of a specific procoagulant factor in the platelet other than factor V or phospholipids.
已将从牛血小板获得的促凝活性与从血小板中分离的脂质的促凝活性进行了比较，比较时添加和未添加纯化的牛因子V。采用一种单阶段测定法，该方法由含有经蛇毒激活的因子X的脱脂牛血浆组成，用于评估活性。在低脂质浓度下，提取的血小板脂质的超声处理囊泡与裂解血小板之间未发现凝血活性差异。然而，在较高脂质浓度下，发现提取的脂质活性低于裂解血小板。对凝胶过滤血小板悬液中的因子V进行测定表明，每毫升含有2×10⁹个血小板的悬液具有正常牛血浆池中约1%的因子V活性。通过超声处理使血小板裂解，因子V活性增加了五倍。向提取的血小板脂质的超声处理囊泡中添加因子V，以使每单位脂质产生与裂解血小板中相同的因子V活性，仅在较高脂质浓度范围内缩短了凝血时间。向脂质囊泡中添加的因子V量再增加三倍，使得在测试的整个磷脂浓度范围内，脂质囊泡的凝血特性与裂解血小板的凝血特性无法区分。当通过降低底物血浆中因子Xa的浓度来改变测试条件时，裂解血小板与提取的血小板脂质之间的差异完全消失。得出的结论是，与提取的血小板脂质相比，裂解血小板的较高促凝活性可归因于血小板因子V活性。因此，除了因子V或磷脂之外，没有令人信服的必要假设血小板中存在特定的促凝因子。
