神经
词汇介绍
拓展阅读
解析
thrombin 英 ['θrɒmbɪn] 美 ['θrɑmbɪn]
释 义 n. [生化] 凝血酶
例 句 The ultimate result is the formation of the thrombin and fibrin clot, and each enzymolysisaccompaniment magnify effective. 最终结果是凝血酶和纤维蛋白凝块的形成，而且每步酶解反应均有放大效应。
概述
概述
凝血酶也称为凝血因子IIa（FIIa)，由其无活性前体凝血酶原转化而成，是丝氨酸蛋白酶和维生素K依赖性凝血因子家族的成员，参与凝血过程的各个环节，在凝血级联中起关键作用。在凝血反应中，凝血酶通过正负反馈，发挥着促凝和抗凝双重调节作用，维持机体凝血系统的平衡。近年来发现，凝血酶除了在凝血级联中发挥重要作用外，与炎症及炎症相关的多种疾病也关联密切，累及神经、消化、心血管、运动、呼吸、内分泌等多个系统。
结构
凝血酶来源于其无活性的酶原形式-凝血酶原，一种在肝脏中合成并分泌到血液中的70KD糖蛋白。在凝血级联激活过程中凝血酶原活化后形成35. 5KD 的凝血酶。凝血酶由轻链A和重链B组成，其中A 链含36个残基，呈回旋状位于分子背部，维持整体结构的稳定。B链含259个残基，由两个相邻的β-桶、两个螺旋以及部分表面环组成。凝血酶的活性部位在两个β-桶之间，形成一个类似口袋的裂缝，Ser-195，His-57，Asp-102 残基组成的催化三联体分布其中。凝血酶表面电荷分布不均匀，因而产生了局部的高正、负电场，其中有两个正电区域，一个负电区域较受关注，负电区域位于凝血酶活性部位，两个正电区域分别位于活性部位两侧并向外延伸形成阴离子结合位点Ⅰ和Ⅱ，提高了凝血酶与底物的亲和力。
指征和剂量
用于外伤、手术、口腔、耳鼻喉、泌尿、妇产科及消化道等部位的局部止血。
用量：①局部止血：朋灭菌生理盐水溶解为50～1000U/ml，喷雾或灌注于创面；或以明胶海绵、纱条蘸本品贴敷于创面；也可直接撒布粉末于创面。②消化道止血：用适当生理盐水或温牛乳溶解本晶，使成50～500U/ml，口服或灌注．500～2 000 U．q6h根据出血部位和程度，适当增减浓度、用量和次数。
注意事项
①本品严禁血管内、肌内或皮下注射，可导致局部坏死，危及生命。②出现过敏症状时，应立即停药。③溶液状态的凝血酶会很快灭活，所以临用时新鲜配制。④本品必须直接与创面接触，才能起止血作用。
复制标题肝硬化和凝血病患者新鲜冰冻血浆输注: 对常规凝血试验和血栓调节蛋白修饰凝血酶生成的影响
发表时间：2019-09-16
影响指数：18.9
作者： Amanda Bruder Rassi
期刊：J Hepatol
BACKGROUND AND AIMS:The efficacy of fresh frozen plasma (FFP) transfusion in enhancing thrombin generation in patients with cirrhosis and impaired conventional coagulation tests has not been sufficiently explored.METHODS:Fifty-three consecutive patients receiving a standard dose of FFP to treat bleeding and/or before invasive procedures if prothrombin time (PT) ratio-INR was ≥1.5 were prospectively enrolled. Primary endpoint was the amelioration of endogenous thrombin potential (ETP) with thrombomodulin (ETP-TM) after transfusion, which corresponds to the total amount of generated thrombin. PT-INR, aPTT were also assessed before and after transfusion.RESULTS:FFP enhanced ETP-TM by 5.7%, from 973 [731-1258] to 1028 [885-1343] nM x min; p= 0.019). Before transfusion, evidence of normal or high ETP-TM was found in 94% of patients, even in those with bacterial infections. Only 1 (1.9%) patient had ETP-TM values reverting to the normal range after transfusion. Notably, no patients with low ETP-TM had bleeding. The median decrease in ETP-TM was 8.3% and the mean was 12.8% in 18 (34%) after transfusion (from 1225 [1071-1537] to 1124 [812-1370] nM x min; p=<0.0001). Similar responses to FFP transfusion were observed in patients with compensated and acute descompensated cirrhosis, ACLF, infection or shock. FFP significantly ameliorated INR and aPPT values (p < 0.0001), but in a minority of patients the values were reduced to less than the cut-off point of 1.5.
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