Quantification of contact system activation using a radiometric assay for activated factor IX.
Quantification of contact system activation using a radiometric assay for activated factor IX.
复制标题
使用放射测定法对活化因子 IX 进行接触系统活化的量化。
作者：
R. Berkowitz;Y. Nemerson
描述了一种量化人体血浆接触系统激活的辐射测定法。该测定利用氚化牛因子 IX 作为探针并测量其放射性标记的激活肽的释放。溶于三氯乙酸。使用硅藻土作为活化剂。随着硅藻土浓度从 0 mg/mL 血浆增加到 5 mg/mL，因子 IX 激活率无症状地增加。变化超过100倍。平行活化的部分凝血活酶时间显示出六倍的变化。将我们的数据拟合成双曲线方程。产生 1 .24 ± 0.21 mg 硅藻土/mL 血浆的 K112 和 1125 ± 65 cpm/min 的 V,,,。可以使用该系统比较各种材料的接触活化。要么通过测定它们各自的 K112 值，要么通过将物质的接触激活能力与标准品（如硅藻土）的接触激活能力联系起来。使用物质的测量反应速度和上述方程。使用后一种方法，我们确定硅藻土在激活接触系统方面比涤纶主动脉移植物更有效 345 倍。放射测定可以比凝血测试更精确地量化接触系统的激活，并且可以用于比较各种材料的接触激活能力。这表明它在寻找生物相容性方面具有潜在的用途。非血栓形成的人造表面和假体。
A radiometric assay to quantify activation of the contact system of human plasma is described. The assay utilizes tritiated bovine factor IX as a probe and measures release of its radiolabeled activation peptide. which is soluble in trichloracetic acid. Using celite as an activator. rate of factor IX activation increased asymptomatically as celite concentration increased from 0 to 5 mg/mI plasma. changing over 100-fold. Parallel activated partial thromboplastin times showed a sixfold change. Fitting our data to an equation for a hyperbola. yielded a K112 of 1 .24 ± 0.21 mg celite/mI plasma and a V,,, of 1125 ± 65 cpm/min. Contact activation of various materials can be compared using this system. either by determining their respective K112 values, or by relating the contact activating ability of a substance to that of a standard such as celite. using the substance’s measured reaction velocity and the above equation. Using the latter method we determined that celite is 345-fold more potent than Dacron aortic graft in activating the contact system. The radiometric assay can quantify activation of the contact system more precisely than a clotting test and can be used to compare the contact activating ability of various materials. This suggests its potential usefulness in the search for biocompatible. nonthrombogenic artificial surfaces and prostheses.