Interaction of a plasminogen activator proteinase, LV-PA with human alpha2-macroglobulin.

Lachesis venom plasminogen activator (LV-PA) is a 33-kDa serine proteinase isolated from bushmaster (Lachesis muta muta) snake venom, which activates the fibrinolytic system in vitro. This study has examined the effect of the plasma proteinase inhibitor alpha2-macroglobulin (alpha2-M) towards LV-PA and compares it with the effect on tissue type plasminogen activator (t-PA). The proteolytic activity of LV-PA alone or previously incubated with human plasminogen (Plg) on the large molecular mass protein substrates, dimethylcasein (DMC) and fibrinogen (Fg) was completely inhibited by human alpha2-M. However, the synthetic peptides Tos-Gly-Pro-Lys-pNA and H-D-Pro-Phe-Arg-pNA (S-2302) were hydrolyzed with almost no reduction in rate. At pH 7.4 and 37 degrees C the proteinase (0.15 microM over 15 min) interacted with alpha2-M, and each mole of alpha2-M bound 2 mol of enzyme. Sodium dodecyl sulfate gel electrophoresis of reduced samples showed that the interaction of alpha2-M with either LV-PA or t-PA preincubated with Plg resulted in the formation of approximately 90 kDa fragments and high molecular mass complexes (Mr 180 kDa), generated by the incubation mixture (LV-PA or t-PA) and Plg. The data suggest that LV-PA is a direct-type PA and its fibrinolytic effect can be reduced by alpha2-M in vivo.     

多发性骨髓瘤患者血浆尿激酶型纤溶酶原激活物及其可溶性受体的检测与临床意义

目的 :研究多发性骨髓瘤 ( MM)患者血浆尿激酶型纤溶酶原激活物 ( u- PA )及其可溶性受体 ( su PAR )的水平变化 ,并探讨其临床意义。方法 :用 ELISA法检测 34例 MM患者血浆 u- PA及 su PA R的浓度 ,同时观察其中6例 MM患者化疗前后血浆 u- PA及 su PAR的浓度变化。结果 :MM患者血浆 u- PA及 su PA R水平均明显高于正常对照组 ,其中进展期 MM患者血浆 u- PA及 su PAR水平明显高于正常对照组和稳定期 MM患者 ( P <0 .0 1) ,而稳定期 MM患者血浆 u- PA及 su PA R水平与正常对照组无显著性差异 ( P>0 .0 5)。 6例 MM患者化疗后血浆 u- PA及 su PA R水平 ,明显低于化疗前血浆 u- PA及 su PAR水平 ( P<0 .0 5)。骨髓涂片瘤细胞比例 >2 0 %的 MM患者血浆 u- PA及 su PA R水平 ,明显高于瘤细胞比例≤ 2 0 % M M患者 ( P<0 .0 5;P<0 .0 1)。M M患者血浆 u- PA及su PA R水平均与骨髓瘤细胞百分比及血清球蛋白呈正相关 ,而与血清白蛋白呈负相关。结论 :血浆 u- PA及 su PA R水平升高可能与多发性骨髓瘤的发生、发展有密切关系 ;其水平可作为临床分期、判断疗效、了解疾病进展情况及预后的一个重要指标。     

蚓激酶生物活性检测方法的研究

本文采用组织纤溶酶原激活剂（ＴＰＡ）─纤维蛋白平板法测定蚓激酶的生物活性。该法操作简便，易于观察，重现性好。     

Plasminogen activator is involved in the hCG-induced neutrophil extravasation and vasopermeability increase in the rat testis

The role of proteolytic enzymes in the hCG-induced increase in testicular vasopermeability and neutrophil extravasation was studied using protease inhibitors. An intra-testicular injection of hCG together with incubation medium conditioned by polymorphonuclear leucocytes (PMNs) caused a significant increase in vasopermeability and a coincident extravasation of PMN's from the postcapillary venules in the rat testis. When p-aminobenzamidine, a serine protease inhibitor which inhibits urokinase-type plasminogen activator, was administered together with hCG in the incubation medium, both the permeability increase and PMN extravasation were prevented. Aprotinin, another serine protease inhibitor, and Eglin C, a specific neutrophil elastase and cathepsin G inhibitor were, however, without effect. None of these inhibitors caused any non-specific vascular effects in the testis at the concentrations used. These results support the concept that the hCG-induced increase in vasopermeability in the rat testis is related to extravasation of PMNs and suggest that urokinase-type plasminogen activator is involved in migration of these cells through the postcapillary venular walls.     

What the structure of angiostatin may tell us about its mechanism of action

Summary.  Originally discovered in 1994 by Folkman and coworkers, angiostatin was identified through its antitumor effects in mice and later shown to be a potent inhibitor of angiogenesis. An internal fragment of plasminogen, angiostatin consists of kringle domains that are known to be lysine-binding. The crystal structure of angiostatin was the first multikringle domain-containing structure to be published. This review will focus on what is known about the structure of angiostatin and its implications in function from the current literature.     

急性脑梗死患者血浆纤溶酶原激活物及其抑制剂-1水平的动态变化及其与梗死面积的关系

目的 探讨急性脑梗死患者血浆组织型纤溶酶原激活物(t-PA)及其抑制剂-1(PAI-1)水平的动态变化及其与梗死面积的关系.方法 急性脑梗死患者100例,其中大面积脑梗死22例、小面积脑梗死36例、腔隙性脑梗死42例,采用发色底物显色法检测脑梗死患者病后24 h、2 d、14 d、21 d的血浆t-PA、PAI-1水平,与正常对照组比较;并比较不同面积脑梗死患者血桨t-PA、PAI-1水平.结果 与正常对照组比较,急性脑梗死患者病后24 h、2 d、14 d血浆t-PA水平显著降低,血浆PAI-1水平明显升高(均P＜0.01);病后21 d两者与正常对照组差异无统计学意义(均P＞0.05);大面积脑梗死患者t-PA水平明显低于小面积和腔隙性脑梗死患者,小面积脑梗死患者又明显低于腔隙性脑梗死患者(均P＜0.01);不同面积脑梗死组之间PAI-1水平未见明显差异(均P＞0.05).结论 脑梗死患者急性期血浆t-PA水平降低及PAI水平升高;脑梗死面积越大的患者血浆t-PA水平降低程度越明显,而血浆PAI-1水平与梗死面积无关.     

特异性DNA倍增技术检测t-PA cDNA基因在表达细胞中的稳定性

利用特异性DNA倍增技术(polymerase chain Reaction,PCR)检测t-PA cDNA基因在表达细胞基因组中的稳定性,并对所得的PCR反应产物进行了限制性内切酶片段、分子杂交和核苷酸顺序分析等方面的研究,证实了t-PA cDNA基因已插入到表达细胞染色体中。这种方法快速、简便、灵敏度和特异性高,是检测基因工程表达细胞中cDNA基因稳定整合状况的好方法。     

中国人血管抑素基因的克隆及其序列分析

目的：克隆中国人血管抑素(angiostatin，ANG)基因全长并进行序列分析。方法：应用RT-PCR，将5例健康人肝脏组织ANG基因克隆到pSP71载体上，用Sanger法进行基因测序分析。结果：通过RT-PCR获得一个1141bp的扩增产物，测序发现与已报道的ANG比较，国人ANG上有3个碱基突变位点：分别为第825位C→T；第927位T→G和第1078位G→A。前两个碱基突变氨基酸未发生变化，第3个碱基突变结果使缬氨酸(Val342)改变成为蛋氨酸(Met342)。结论：克隆得到中国人ANG基因片段，其碱基和氨基酸的变化可能是人群中该基因的遗传多态现象。     

组织型纤溶酶原激活物双单抗夹心ELISA建立及临床应用

本文动用自制ｔ－ＰＡ单克隆抗体建立ｔ－ＰＡ：Ａａ夹心ＥＬＩＳＡ法。结合ｔ－ＰＡ：Ａ、ＰＡＩ：Ａ测定，对５０例正常人，８７例肝病，４７例冠心病和１９例深静脉血栓 成患者的血浆ｔ－ＰＡ：Ａｇ、ｔ－ＰＡ：Ａ、ＰＡＩ：Ａ水平进行了研究。     

纤溶酶原激活物抑制物-1基因4G/5G基因型分布频率与心肌梗死和脑梗死相关性初步分析

目的研究我国汉族人纤溶酶原激活物抑制物-1基因启动子区-675位4G/5G(单鸟嘌呤核苷酸插入/缺失)基因多态性与心肌梗死和脑梗死的等位基因特异性的相关性.方法以等位基因特异性聚合酶链反应(AS-PCR)扩增56例心肌梗死患者,54例脑梗死患者,83例无关健康对照个体的基因组DNA,鉴定PAl-1 4G/5G基因型及分布频率,常规方法检验研究个体的主要临床和生化指标.结果PAI-1基因启动子区4G/5G基因多态性在心肌梗死,脑梗死患者组中的分布频率与对照组明显不同.在心肌梗死组中,4G/4G基因型分布频率(71.40%)比对照组(30.12%)显著增加(P＜0.001),杂合型4G/5G基因型分布频率(25.00%)比对照组(62.65%)明显降低;而在脑梗死组中,4G/4G,4G/5G基因型分布频率(分别为20.37%,55.56%)均比对照组(分别为30.12%,62.65%)低,5G/5G基因型明显增加(24.07%vs7.32%,P＜0.001).而且心梗组中血浆PAI-1活性水平随着4G等位基因的减少而降低;脑梗死组中,血浆PAI-1活性水平随着5G等位基因的升高而增加.心肌梗死、脑梗死患者组中的血浆PAI-1活性水平,甘油三酯水平和血糖水平都比对照组明显升高(分别为P＜0.001,P＜0.05,P＜0.001).结论本研究表明,中国汉族人PAI-1基因启动子区4G/5G基因多态性可能和心肌梗死、脑梗死发生的危险性相关,4G/5G基因多态性可能是一种重要的遗传性血栓性疾病的危险因子.