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1.
褐藻糖胶是一种含有硫酸基的水溶性杂多糖,其抗凝血与抗血栓等生理机能与肝素类似。用分子动力学计算,模拟抗凝血酶Ⅲ结合褐藻糖胶的结构变化。抗凝血酶Ⅲ和褐藻糖胶结合时Arg393从抗凝血酶Ⅲ的内部激发到了分子表面,Arg393与凝血酶活性中心的Asp、His、Ser结合,继而进入到四面体的过渡状态。 相似文献
2.
Tick anticoagulant peptide (TAP) is a novel inhibitor of blood coagulation factor Xa 总被引：24，自引：0，他引：24
A low molecular weight serine protease inhibitor (TAP) was purified from extracts of the soft tick, Ornithodoros moubata. The peptide is a slow, tight-binding inhibitor, specific for factor Xa (Ki = 0.588 +/- 0.054 nM). The inhibitor also acts as an anticoagulant in several human plasma clotting assays in vitro. Its amino acid sequence (60 residues) has limited homology to the Kunitz-type inhibitors. However, unlike other inhibitors of this class, TAP inhibits only factor Xa. It had no effect at a 300-fold molar excess on factor VIIa, kallikrein, trypsin, chymotrypsin, thrombin, urokinase, plasmin, tissue plasminogen activator, elastase, or Staphylococcus aureus V8 protease. TAP's specificity and size suggest that it may have therapeutic value as an anticoagulant. 相似文献
3.
[目的]研究不同抗凝剂对鲫鱼外周血的抗凝效果。[方法]以鲫鱼"中科3号"为研究对象,比较5种抗凝剂对鲫鱼外周血的抗凝效果,探讨其适宜抗凝剂品种和有效抗凝浓度。[结果]除了L-半胱氨酸在试验条件下不能作为有效抗凝剂外,其余4种抗凝剂延长血液凝固时间均在61.43 min以上。肝素钠、柠檬酸钠、草酸钾和EDTA的有效抗凝浓度分别为(0.80±0.17)、(1.42±0.14)、(1.17±0.14)和(2.33±0.58)mg/mL。显微镜下,肝素钠、柠檬酸钠、草酸钾和EDTA 4种抗凝剂均能较好地维持鲫鱼外周血细胞的形态。[结论]该研究结果可为鲫鱼外周血抗凝剂的应用提供参考。 相似文献
4.
The regulation of natural anticoagulant pathways 总被引：38，自引：0，他引：38
C T Esmon 《Science (New York, N.Y.)》1987,235(4794):1348-1352
Vascular endothelium plays an active role in preventing blood clot formation in vivo. One mechanism by which prevention is achieved involves a cell surface thrombin-binding protein, thrombomodulin, which converts thrombin into a protein C activator. Activated protein C then functions as an anticoagulant by inactivating two regulatory proteins of the coagulation system, factors Va and VIIIa. The physiological relevance of the protein C anticoagulant pathway is demonstrated by the identification of homozygous protein C--deficient infants with severe thrombotic complications. Recent studies suggest that this pathway provides a link between inflammation and coagulation. 相似文献
5.
目的观察重组线虫抗凝蛋白rAcaNAP9抗大鼠颈总动脉血栓的效果。方法将40只SD大鼠随机分为rAcaNAP9低剂量组（40μg/kg）、中剂量组（200μg/kg）、高剂量组（1 mg/kg）、阳性药对照组（肝素钠,1650 U/kg）和模型对照组共5组,每组8只。分离大鼠一侧颈总动脉,从鼠尾静脉给药后,即用血栓生成仪对动脉进行恒流电刺激5min,检测受刺激血管的堵塞程度。结果模型对照组的血管堵塞程度和rAcaNAP9低、中、高3个剂量组比较差异均有统计学意义（P〈0.05或0.01）。结论重组线虫抗凝蛋白rAcaNAP9具有抗大鼠颈总动脉血栓效果。 相似文献
6.
S. Yu. Zavalishina 《Russian Agricultural Sciences》2012,38(4):321-323
An investigation of 32 healthy Black Pied and Simmental calves in the milk-feeding stage established a stable content in their blood of acyl hydroperoxides and thiobarbituric acid reactive substances aver- aging in this stage respectively 1.51 D233/ml and 3.53 ??mol/L with a tendency toward intensifying the activity of the antioxidant potential of plasma. Against a background of a low level of endotheliocytemia, there was a tendency toward an increase of the index of antiaggregation activity of the vascular wall with all tested inducers (ADP 1.77, collagen 1.63, thrombin 1.53, ristomycin 1.53, epinephrine 1.66) and their combinations (ADP + epinephrine 1.44, ADP + collagen 1.37, epinephrine + collagen 1.49). Endotheliocytes are characterized by intensified production of antithrombin III providing the necessary level of anticoagulants of vascular origin in blood (the index of anticoagulant activity of the vascular wall was 1.32 on average). In this case, secretion of tissue plasminogen activators, revealed upon creating temporary ischemia of the venous wall of calves aged from 11 to 30 days, had a general tendency to intensify (the index of fibrinolytic activity of the vascular wall increased during the stage by 2.1%). 相似文献
7.
Cigarette smoke contains anticoagulants against fibrin aggregation and factor XIIIa in plasma 总被引：1，自引：0，他引：1
Gas-phase, water-soluble components of cigarette smoke cause delayed fibrin self-assembly and prevent fibrin cross-linking by inactivation of factor XIIIa (plasma transglutaminase). These anticoagulant properties of smoke are demonstrable in plasma, suggesting they play a role in the pathophysiology of smoking. 相似文献
8.
3种禽血抗凝剂效果及其对DNA提取质量的影响 总被引：2，自引：1，他引：1
通过3种不同血液抗凝剂对禽血抗凝,提取新鲜的和经冷冻保存一段时间后的抗凝血DNA,运用紫外分光法、凝胶电泳和PCR扩增技术检测提取的DNA样品质量,探讨不同抗凝剂的抗凝效果及其对提取DNA质量的影响。结果表明:3种抗凝血提取的DNA纯度和浓度相近。新鲜抗凝血比冷冻保存一段时间后的抗凝血提取的DNA质量好。ACD抗凝血在冷冻一段时间后出现凝血块,EDTA抗凝血液放置时间过长也影响抗凝效果,但两者在加入裂解液后则可长时间保存。75%乙醇抗凝剂抗凝效果较好,可长时间保存,适合远距离采血。由3种抗凝禽血提取的DNA分子片段完整,能满足常规分子生物学试验研究。 相似文献
9.
Role of histone H3 lysine 27 methylation in X inactivation 总被引：1，自引：0，他引：1
Plath K Fang J Mlynarczyk-Evans SK Cao R Worringer KA Wang H de la Cruz CC Otte AP Panning B Zhang Y 《Science (New York, N.Y.)》2003,300(5616):131-135
The Polycomb group (PcG) protein Eed is implicated in regulation of imprinted X-chromosome inactivation in extraembryonic cells but not of random X inactivation in embryonic cells. The Drosophila homolog of the Eed-Ezh2 PcG protein complex achieves gene silencing through methylation of histone H3 on lysine 27 (H3-K27), which suggests a role for H3-K27 methylation in imprinted X inactivation. Here we demonstrate that transient recruitment of the Eed-Ezh2 complex to the inactive X chromosome (Xi) occurs during initiation of X inactivation in both extraembryonic and embryonic cells and is accompanied by H3-K27 methylation. Recruitment of the complex and methylation on the Xi depend on Xist RNA but are independent of its silencing function. Together, our results suggest a role for Eed-Ezh2-mediated H3-K27 methylation during initiation of both imprinted and random X inactivation and demonstrate that H3-K27 methylation is not sufficient for silencing of the Xi. 相似文献
10.
杜仲叶黄酮降血脂及抗氧化作用的研究 总被引：1，自引：0，他引：1
[目的]进一步了解杜仲叶降血脂、抗氧化作用的活性,以期为杜仲的综合开发利用提供依据。[方法]将ICR小鼠按体重随机分为正常对照组和高脂饲料组,正常对照组动物从试验开始至结束用普通饲料喂养,高脂饲料组动物均喂高脂饲料,制造成营养性高脂血症模型供试小鼠。再将高脂饲料组动物按体重随机分为模型对照组,阳性药对照组,黄酮大、中、小剂量组,动物继续给予高脂饲料,模型对照组每天给予相应体积的溶媒,黄酮大、中、小3个剂量组,分别以45、15和5mg/（kg.d）剂量的黄酮灌胃给药,阳性药组给予5mg/（kg.d）的洛伐他汀（相当于人用剂量按照标准体表面积折算后小鼠用剂量的2倍）,正常对照组给以等体积溶媒。17d后,各组小鼠均禁食12h,眼眶取血,肝素抗凝,各取0.2ml血液溶血后用于CAT测定,其余抗凝血液离心分离血浆用于血脂及POD、MDA的测定。[结果]与高脂血症模型组相比较,杜仲叶黄酮给药组动物的血浆总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、动脉粥样硬化指数（AI）均有不同程度的降低,高密度脂蛋白胆固醇（HDL-C）有所上升,血中过氧化氢酶（CAT）、过氧化物酶（POD）活性增强,血浆中丙二醛（MDA）的含量下降。[结论]杜仲叶黄酮具有降低营养性高脂血症小鼠血脂和抗氧化的作用。 相似文献
11.
12.
[目的]研究EuTiNiO4Cl纳米晶的抗凝血作用。[方法]利用溶胶凝胶法制备EuTiNiO4Cl纳米晶,在一定温度下真空干燥凝胶,在不同温度下进行X射线衍射分析,之后用不同浓度的EuTiNiO4Cl纳米晶对体重为(20±2)g的健康小白鼠进行灌胃,以血液出现拉丝现象作为测定血液凝固的指标,研究EuTiNiO4Cl纳米晶的抗凝血作用。[结果]在350、400和450℃时纳米晶的XRD峰非常宽,说明此温度下其晶型为不定型;在500、600和700℃时纳米晶的XRD峰高而尖;EuTiNiO4Cl纳米晶的粒径随温度的升高而增大,其晶型由不定型变为多晶型。抗凝血试验表明EuTiNiO4Cl纳米晶具有良好的抗凝血作用。当EuTiNiO4Cl纳米晶浓度为2.5×10-3mol/L时,其抗凝血效果最好。[结论]EuTiNiO4Cl纳米晶的抗凝血性能良好。 相似文献
13.
肝素雾化吸入治疗肺心病高粘血症的疗效观察 总被引：1，自引：0，他引：1
慢性肺心病并高粘血症患者５０例随机配对分为：（１）治疗组２５例用综合治疗加肝素雾化吸入；（２）对照组２５例单用综合治疗，结果显示，治疗组的疗效明显优于对照组（Ｐ〈０．０１），治疗组内的出，凝血时间，凝血酶原时间在治疗前扣比较无差异（Ｐ〉０．０５）。 相似文献
14.
Heparin has been chemically combined with a number of plastic surfaces rendering them nonthrombogenic as judged by Lee-White coagulation tests in vitro with human blood. Addition of quaternary ammonium groups to the plastic permitted formation of insoluble complexes with heparin. These heparinized surfaces were essentially nonthrombogenic and adsorb blood proteins to a significantly smaller degree from dilute solution than do the unmodified plastic surfaces. The affinity of the formed blood elements for these modified surfaces is much less than for the unmodified surfaces. 相似文献
15.
Xu Y Masuko S Takieddin M Xu H Liu R Jing J Mousa SA Linhardt RJ Liu J 《Science (New York, N.Y.)》2011,334(6055):498-501
Ultralow molecular weight (ULMW) heparins are sulfated glycans that are clinically used to treat thrombotic disorders. ULMW heparins range from 1500 to 3000 daltons, corresponding from 5 to 10 saccharide units. The commercial drug Arixtra (fondaparinux sodium) is a structurally homogeneous ULMW heparin pentasaccharide that is synthesized through a lengthy chemical process. Here, we report 10- and 12-step chemoenzymatic syntheses of two structurally homogeneous ULMW heparins (MW = 1778.5 and 1816.5) in 45 and 37% overall yield, respectively, starting from a simple disaccharide. These ULMW heparins display excellent in vitro anticoagulant activity and comparable pharmacokinetic properties to Arixtra, as demonstrated in a rabbit model. The chemoenzymatic approach is scalable and shows promise for a more efficient route to synthesize this important class of medicinal agent. 相似文献
16.
X-Chromosome inactivation in cloned mouse embryos 总被引：2，自引：0，他引：2
Eggan K Akutsu H Hochedlinger K Rideout W Yanagimachi R Jaenisch R 《Science (New York, N.Y.)》2000,290(5496):1578-1581
To study whether cloning resets the epigenetic differences between the two X chromosomes of a somatic female nucleus, we monitored X inactivation in cloned mouse embryos. Both X chromosomes were active during cleavage of cloned embryos, followed by random X inactivation in the embryo proper. In the trophectoderm (TE), X inactivation was nonrandom with the inactivated X of the somatic donor being chosen for inactivation. When female embryonic stem cells with two active X chromosomes were used as donors, random X inactivation was seen in the TE and embryo. These results demonstrate that epigenetic marks can be removed and reestablished on either X chromosome during cloning. Our results also suggest that the epigenetic marks imposed on the X chromosomes during gametogenesis, responsible for normal imprinted X inactivation in the TE, are functionally equivalent to the marks imposed on the chromosomes during somatic X inactivation. 相似文献
17.
Intravenous injection of autologous lipoprotein (thromboplastin) or thrombin produced a lethal, hemorrhagic syndrome in chicken embryos. The embryos could be protected from this fatal result by injection of antithrombin III, an alpha(2)-globulin (molecular weight 60,000 to 80,000) purified from human, bovine, and guinea pig blood. Heparin also protected the embryos, but other inhibitors were less protective. 相似文献
18.
The cerebellar flocculus has been implicated in vestibulo-oculomotor control. One major central input to this structure originates from brainstem cells in the paramedian tract (PMT), whose function is unknown. Here it is reported that PMT cells in the pons carry vestibular and eye movement signals and their pharmacological inactivation produces a leaky integrator combined with vestibular imbalance. The results suggest that PMT cells provide the cerebellum with sensory and motor signals that are essential for velocity-to-position integration, a common premotor process that is required in all motor systems. 相似文献
19.
Control of angiogenesis with synthetic heparin substitutes 总被引：15，自引：0，他引：15
Many diseases are dominated by persistent growth of capillary blood vessels. Tumor growth is also angiogenesis-dependent. Safe and effective angiogenesis inhibitors are needed to determine whether control of angiogenesis would be therapeutic. Heparin and certain steroids, administered together, can inhibit angiogenesis in a synergistic manner. This "pair" effect suggested that specific hydrophilic cycloamyloses may be suitable heparin substitutes. beta-Cyclodextrin tetradecasulfate administered with a steroid inhibits angiogenesis at 100 to 1000 times the effectiveness of heparin in the chick embryo bioassay. This cyclic oligosaccharide also augments the anti-angiogenic effect of angiostatic steroids against corneal neovascularization in rabbits when beta-cyclodextrin tetradecasulfate and a steroid are inserted into the cornea or applied topically as eyedrops. 相似文献