Analysis of Neonatal Hemostatic and Thrombotic Mechanism, and Exploring of the New Therapeutic Approach.

应用血栓弹力图（TEG）研究新生儿止血机制。新生儿早期，新生儿全血TEG的r、k值较成人全血缩短，ma值较成人全血增大。这种新生儿TEG的特征性高凝前体能够通过向正常成人全血中加入活化的凝血因子（如凝血酶、活化的凝血因子VIIa、ADP或肾上腺素）来重建。其中一个数据，激活因子VIIa的结果，最近提交给杂志“血栓形成和止血”附在小册子。另一篇关于高凝状态与抗血栓药物的关系的论文最近被订阅。尽管新生儿血小板功能低下，维生素K依赖性凝血因子浓度较成人低，但新生儿的出血时间和凝血时间基本正常。但是，在病理状态下，新生儿血栓形成的发生率高于新生儿以后的儿童。对于新生儿的止血机制仍不清楚。从我们最近的研究，血管性血友病因子（vWF）相对较高，血管性血友病因子裂解蛋白酶是低出生体重至足月新生儿的脐带血低。此外，检测到较高的vWF多聚体。vWF的这种更高的多聚体在止血方面更有效。提示与新生儿接近正常出血时间有关。我们还研究了脐带血中剪切依赖性血小板聚集。低切应力和高切应力下血小板聚集率均较低，并通过重组血液成分和体外ATP活性的测定分析了其机制。脐血Ecto-ATPase活性高于成人血。提示外ATP酶可能与抗血栓机制有关。

Neonatal hemoatatic mechanism was studied using thrombelastgram (TEG). In the early neonatal period, the r and k values of TEG in neonatal whole blood shortened and the ma value of TEG enlarged rather than these values in adult's whole blood. This characterized hypercoagulation prophile of TEG in neonate was able to be recreated by the addition of activated coagulation factors, such as thrombin, activated factor VIIa, ADP or epinephrine into normal adult whole blood. One of data, the results of activated factor VIIa, was recently submitted to the journal " Thrombosis and Haemostatic" enclosed in the booklet. And another paper concerning about the relationship between the hyper coagulation and anti-thrombotic drugs was recently subscribed. The bleeding time and coagulation time were almost normal in neonate despite the low function of platelets and the low concentrations of vitamin K dependent coagulation factors in neonate compared with adults. But, in pathological state, the thrombosis is more frequent in neonate than in children after neonate. The knowledge of the haemostatic mechanism is still obscure in neonate. From our recent study, von Willebrand factor (vWF) was relatively high and von Willebrand factor-cleaving protease was low in cord bloods of low birth weight to full term neonate. Furthermore, the higher multimer of vWF was detected. This higher multimer of vWF is more potent in hemostasis. And it may be suggested that it is related to be near normal bleeding time in neonate. We have also studied on the shear dependent platelet aggregation in cord bloods. And the low and high shear stress platelet aggregation were low, this mechanism were analyzed by the recreated blood components and the measurement of ecto-ATP activity. Ecto-ATPase in cord bloods was higher than that in adult blood. It may be suggested that ecto-ATP ase is related to the anti-thrombotic mechanism.