THROMBOLYSIS BY RAPID DIRECT-ACTING FIBRINOLYTIC AGENTS

血栓栓塞性血管疾病占所有疾病的很大一部分 美国的发病率和死亡率。溶栓疗法，使用 系统或选择性地使用纤溶酶原激活剂，已经获得了 越来越多的人接受血栓栓塞症的治疗。 然而，溶栓治疗仍需进一步改进。 我们寻找一名更有效、更安全的特工，导致我们调查 蛇的毒液。1956年，几名研究人员描述了纤溶 各种蛇毒的性质，并提到提纯的蛇毒 组分可能在临床上用作溶栓剂。研究表明， 因此，我们的实验室已经开始提纯和表征 蛇毒纤溶酶。这些调查采用了一种新的方法 用于纯化纤溶酶和一种新的体内血管造影术模型 评估他们的治疗效果。我们已经提纯了一种 凝胶法提取南方铜鱼蛇毒纤溶酶 Sephadex G-100过滤和离子交换层析 羧甲基纤维素和二乙氨基乙基纤维素。这种酶证明了 钠溶液中的聚丙烯酰胺凝胶电泳法均一 十二烷基硫酸盐。这种酶似乎并不能激活纤溶酶原，相反 它对纤维蛋白有直接的溶解作用。体内活性将被评估 对抗新鲜血栓栓子进入兔肾脏。兔肾 动脉将被分流，并遵循对照动脉造影标准 体积的凝块(兔或人)，将被注射到每个肾脏 完全肝素化的兔子。测试的纤溶酶将被注入 仅进入一条肾动脉，而对侧肾动脉作为 控制力。溶栓治疗将每隔一段时间进行动脉造影术。 到5个小时。一次显着的体内溶栓活性试验 该制剂已在兔体内得到证实，将产生不良反应 评估过了。将评估急性和慢性肾毒性。 输液后的动脉造影、组织学和功能 进入未经栓塞者的肾脏。心血管影响将通过以下方式进行评估 肾内、冠脉内灌注后进行心电图和测压。 凝血参数(凝血酶时间、纤维蛋白原)可能的改变 浓度、凝血时间)将被确定。急慢性 神经毒性将在颈动脉注射后进行测试。通过这种方式， 比较几种酶制剂的治疗比例。那些 治疗比率最高的酶将进一步研究以 它们的生化特性及其对人体的体外活性 纤维蛋白原、纤维蛋白和凝血蛋白。如果这些调查 证实了我们在体内的初步发现，纯化的蛇毒酶 是有效和安全的纤溶剂，这些酶可能会发现广泛的 在人类血栓栓塞病治疗中的应用。

Thromboembolic vascular disease comprises a significant fraction of all morbidity and mortality in the United States. Thrombolytic therapy, using systemically or selectively administered plasminogen activators, has gained increasing acceptance for the treatment of thromboembolic disease. However, further improvements in thrombolytic therapy are still required. Our search for a more effective and safer agent, led us to investigate snake venoms. In 1956, several investigators characterized fibrinolytic properties of various snake venoms and mentioned that purified venom fractions may be clinically useful as thrombolytic agents. Studies have, therefore, been initiated in our laboratories to purify and characterize fibrinolytic snake venom enzymes. These investigations employ a new method for purifying fibrinolytic enzymes and a new in vivo angiographic model for evaluating their therapeutic effectiveness. We have purified a fibrinolytic enzyme from southern copperhead venom by combination of gel filtration on Sephadex G-100 and ion exchange chromatography on carboxymethylcellulose and diethylaminoethylcellulose. The enzyme proved to be homogeneous by polyacrylamide gel electrophoresis in sodium dodecylsulfate. The enzyme does not appear to activate plasminogen, rather it has a direct lytic effect on fibrin. In vivo activity will be assessed against fresh thromboemboli introduced into rabbit kidneys. Rabbit renal arteries will be cateterized and following control arteriograms, standard volumes of clot (rabbit or human), will be injected into each kidney of fully heparinized rabbits. The test fibrinolytic enzyme will be infused into one renal artery only, while the contralateral renal artery serves as control. Thrombolysis will be assessed arteriographically at intervals up to 5 hours. Once significant in vivo thrombolytic activity of the test agent has been demonstrated in the rabbit, adverse effects will be assessed. Acute and chronic renal toxicity will be evaluated arteriographically, histologically, and functionally, following infusion into non-embolized kidneys. Cardiovascular effects will be evaluated by EKG and manometry following intrarenal, and then intracoronary, infusion. Possible alterations of coagulation parameters (thrombin time, fibrinogen concentration, clotting time) will be determined. Acute and chronic neurotoxicity will be tested after intracarotid infusion. In this way, the therapeutic ratio of several enzyme preparations will be compared. Those enzymes with the highest therapeutic ratios will be further studied to characterize their biochemical properties and in vitro activity on human fibrinogen, fibrin and blood coagulation proteins. If these investigations confirm our preliminary in vivo findings that purified snake venom enzymes are potent and safe fibrinolytic agents, these enzymes may find widespread application in the treatment of human thromboembolic disease.