益康唑和克霉唑对血小板聚集及TXB_2和PGE_2生成的影响

益康唑,克霉唑,咪康唑和酮康唑体外抑制AA诱导兔血小板聚集比抑制ADP诱导大鼠血小板聚集的作用强。其中益康唑和克霉唑抑制AA诱聚兔血小板的IC_(50)分别是6.4及11.6μmol/L。放射免疫法测定大鼠血小板产生的TXB_2及PGE_2发现益康唑和克霉唑在5～50 nmol/L浓度下,能抑制TXB_2产生,同时增加PGE_2生成量,并呈良好的剂量效应相关。浓度为0.1～100μmol/L时,TXB_2的生成仍被抑制,而PGE_2的生成量反而逐渐降低。两药对TXB_2生成的抑制作用比Daz强。     

苦豆碱对兔血小板聚集的影响

苦豆碱抑制低浓度花生四烯酸(AA)和胶原诱导的兔血小板聚集,IC_(50)分别为184μg·L~(-1)和38.3mg·L~(-1)提高AA浓度使其抑制作用明显减弱。苦豆碱还抑制兔血小板形成血栓素B_2(TXB_2),此作用可能和其对血小板聚集的抑制有关。     

重组人红细胞生成素对高糖诱导人肾小管上皮细胞增殖及凋亡的影响及其可能机制

目的探讨重组人红细胞生成素(rh EPO)对高糖诱导的正常人肾小管上皮(HK-2)细胞增殖及凋亡的影响及其可能机制。方法将体外培养的HK-2细胞按随机数字表法分为空白对照组、高糖诱导组(高糖终浓度为30mmol/L)、甘露醇对照组(甘露醇浓度为24.5 mmol/L)、rh EPO对照组(rh EPO终浓度为20 U/m L)、不同浓度rh EPO干预组(高糖终浓度为30 mmol/L+rh EPO终浓度分别为5、10、20 U/m L)及Rho激酶抑制剂(Y27632)组(Y27632终浓度为30μmol/L+高糖终浓度为30 mmol/L),各组均刺激24 h。应用RT-PCR法检测各组HK-2细胞Rho A、ROCK1 m RNA的表达;MTT法测定细胞增殖,流式细胞技术分析细胞凋亡。结果高糖诱导组Rho A及ROCK1m RNA表达较空白对照组显著升高(P<0.05),不同浓度rh EPO干预组Rho A m RNA及ROCK1 m RNA的表达较高糖诱导组显著减少(P<0.05),高糖诱导组及不同浓度rh EPO干预组Rho A m RNA与ROCK1 m RNA表达呈正相关。rh EPO可明显促进HK-2细胞增殖(P<0.05),而高糖可诱导正常人肾小管上皮细胞凋亡,加入不同浓度rh EPO或Y27632干预后,其凋亡明显受抑制(P<0.05),且在实验rh EPO浓度范围内,rh EPO促进增殖及抑制凋亡的作用呈现浓度依赖性。结论 rh EPO可促进高糖诱导的HK-2细胞增殖,抑制高糖诱导的HK-2细胞凋亡,其机制可能与阻断Rho A/ROCK信号通路有关。     

尼群地平的抗血小板聚集和抗血栓作用

国产尼群地平(1)对凝血酶(0.15u/ml)诱导的血小极聚集的 IC_(50)是47.5μmol/L,对 ADP(4μmol/L)诱导作用的 IC_(50)是93.9μmol/L。大鼠 iv 1 0.8μg/g 对凝血酶诱导血小板聚集的抑制率为89.8%,对 ADP、AA 诱导血小板聚集的效应也有非常显著的抑制作用。1尚可明显抑制血栓形成。     

6-(αα-二苯基乙酰哌嗪基苯基)-4,5-二氢-5-甲基-3(2H)-哒嗪酮对兔血小板聚集及TXB_2,cAMP的影响

6-(αα-二苯基乙酰哌嗪基苯基)-4,5-二氢-5-甲基-3(2H)-哒嗪酮(简称DMDP)是我院新合成的哒嗪酮的衍生物。DMDP可以显著抑制由花生四烯酸(AA(?),ADP和血小板活化因子(PAF)诱导的免血小板聚集,其IC_(50)分别为1.12±0.1.4.19±0.5和2.97±0.1μmol/L。实验还表明DMDP在1～500 μmol/L浓度范围内呈剂量依赖性地抑制兔血小板内血栓素B_2含量,但升高兔血小板内环腺苷酸水平,这可能是其抑制血小板聚集的作用机理之一。     

2-甲氧基雌二醇联用抗坏血酸诱导慢性粒细胞白血病细胞凋亡及细胞周期变化研究

目的研究2-ME联合抗坏血酸在诱导CML细胞凋亡中的作用以及细胞周期的变化机制。方法收集2016年1~12月期间汕头市中心医院血液科已确诊的bcr/abl(+)慢性粒细胞白血病患者57例骨髓,应用流式细胞术分选出CML细胞并培养传代并随机分为四组。使用抗肿瘤化合物2-甲氧基雌二醇(2-ME)与抗坏血酸(AA)组合来处理慢性粒细胞白血病(CML)细胞,根据药物浓度分为:(1)未加药组;(2)2-ME组(2μmol/L);(3)AA组(62.5μmol/L);(4)2-ME联用AA组(2-ME:2μmol/L+AA:62.5μmol/L)四组。应用流式细胞术分析药物处理后的CML细胞凋亡情况和细胞周期的变化情况。结果用(±s)表示,两组间比较采用t检验,多组间比较用F检验。结果 2μmol/L 2-ME+62.5μmol/LAA组可诱导CML细胞凋亡。2-ME+AA以剂量依赖性方式诱导凋亡,在浓度2~8μmol/L时凋亡呈时间-剂量依赖。2-ME+AA可诱导处于G0/G1期的细胞明显增多,处于S期的细胞减少。结论 2-ME联合抗坏血酸可诱导白血病细胞以时间-剂量依赖式凋亡,且与细胞周期抑制有关。     

替米沙坦对血小板聚集功能影响的体外实验研究

目的观察替米沙坦对血小板聚集功能的影响,探讨替米沙坦抑制血小板聚集的机制。方法采用比浊法测定不同浓度替米沙坦对二磷酸腺苷(ADP)、胶原(COLL)、花生四烯酸(AA)、肾上腺素(EPI)诱导的兔血小板聚集反应抑制情况,并与阿司匹林组对比。结果替米沙坦对ADP、COLL、AA、EPI诱导的血小板聚集均具有浓度依赖性抑制;10-5mol/L替米沙坦和3×10-4mol/L阿司匹林对四种诱导物的抑制率(%)是32.9、20.6、59.1、19.7及36.2、27.7、61.9、26.8,二者无显著性差异(P>0.05)。结论替米沙坦能抑制ADP、COLL、AA、EPI诱导的血小板聚集反应。     

蝙蝠葛碱对血小板聚集及花生四烯酸代谢的影响

蝙蝠葛碱(Dau) 抑制AA及ADP诱导的大鼠血小板聚集,也能抑制AA,ADP及Adr诱导的人血小板聚集。这种抑制作用与Dau剂量呈依赖关系。Dau抑制大鼠洗涤血小板对[1-¹⁴C]AA经环氧酶途径的代谢,TXB₂与HHT的形成均呈剂量依赖性减少。当Dau浓度达到0.1 mmol/L时亦能抑制12-HETE的形成。Dau对AA代谢的上述影响可能是其抑制血小板聚集的机理之一。     

四肽KRDS对犬血小板功能及动脉血栓形成的抑制作用

来自人乳转铁蛋白的四肽(赖—精—门冬—丝氨酸,K RDS)能抑制ADP诱导的犬血小板聚集反应(IC_(50):350μmol/L)和花生四烯酸诱导的血栓烷B_2的产生(IC_(50):175μmol/L),同时,KRDS能抑制凝血酶诱导的血小板表面α—颗粒膜蛋白(GMP-140)的表达(IC_(50):350μmol/L及5—羟色胺的释放(IC_(50):525μmol/L)。另外,KRDS能抑制犬股动脉实验血栓的形成,制备血栓模型4h后,离体血栓的重量为对照组的50%,以~(125)Ⅰ—SZ-51(抗GMP-140的单抗)为示踪剂,离体血栓与血液的放射活性比值仅为对照组的16%。结果提示:四肽KRDS不仅能抑制犬血小板的聚集和释放功能,对体内血栓的形成也有明显的抑制作用,为一生理性抗血栓寡肽。     

新型塔斯品碱衍生物HMQ-T-B10诱导人结肠癌细胞LoVo凋亡作用及机制研究

探讨塔斯品碱衍生物HMQ-T-B10对人结肠癌LoVo细胞生长的影响及其诱导细胞凋亡的可能作用机制。采用MTT法、细胞克隆形成实验、Hoechst染色法、流式细胞术法检测低(2μmol/L)、中(4μmol/L)、高(8μmol/L)3种浓度HMQ-T-B10对LoVo细胞株增殖及凋亡的影响;Western-Blot法检测3种浓度HMQ-T-B10对Bcl-2、Mcl-1、Bax、Cyto-C、Cleaved caspase-3、Cleaved caspase-7蛋白表达水平的影响。MTT法结果显示HMQ-T-B10能明显抑制LoVo细胞的增殖,其半数抑制浓度(IC₅₀)值为(7.9±1.1)μmol/L。细胞克隆形成实验表明3种浓度的HMQ-T-B10均可剂量依赖性抑制LoVo细胞增殖,Hoechst染色及流式细胞术显示HMQ-T-B10可剂量依赖性诱导LoVo细胞凋亡。Western-Blot结果显示4μmol/L及8μmol/L HMQ-T-B10可显著下调Bcl-2蛋白表达并增加Cyto-C表达,3种浓度的HMQ-T-B10均可显著抑制Mcl-1蛋白表达并...     

中国眼镜蛇毒蛋白酶的分离、纯化及其对血小板聚集的影响

目的：从中国眼镜蛇毒中分高纯化出可水解纤维蛋白原的蛇毒蛋白酶,并观察其体内给药对血小板聚集的影响。方法：使用超滤的方法以及肝素亲和层析柱HeparinSepharoseCL－6B和凝胶层析柱SephadexG150分高纯化中国眼镜蛇毒蛋白酶。SDS-聚丙烯酰胺凝胶电泳（SDS－PAGE）检测其纯度和分子量。比浊法测定血小板聚集率。结果：从中国眼镜蛇毒中纯化出具有水解纤维蛋白原活性的蛋白酶,经SDS－PAGE电泳测定为一条带,分子量为47.1kD。该蛋白酶低剂量（0．025mg／kg）、中剂量（0．05mg／kg）以及高剂量（0．1mg／kg）体内给药后,剂量依赖性地抑制ADP（10μmol／L）、胶原（100μg／ml）诱导的兔血小板聚集。结论：具有水解纤维蛋白原活性的中国眼镜蛇毒蛋白酶在体内表现出抑制血小板聚集的作用。     

甲基黄酮醇胺对血小板花生四烯酸代谢通路的影响

甲基黄酮醇胺(MPA)40mg·Kg~(-1)iv,能使花生四烯酸(AA)诱发的小鼠死亡率降低61％.MFA12.5～200μmol·L~(-1)呈剂量依赖性地抑制AA诱导的免血小板聚集.聚集率为49％±10％～4％±4%,对照组为69％±3％.MFA0.1～0.4mmol·L~(-1)呈剂量依赖性抑制AA诱导兔的血小板丙二醛(MDA)的生成,为(nmol·10~(-9)血小板)0.075±0.011～0.111±0.023,对照组为0.170±0.017.MFA0.4 mmol·L~(-1)有效地抑制凝血酶和A A诱导的兔血小板内MDA生成.分别为0.016±0.006.0.080±0.017,对照组分别为0.048±0006,0.160±0.025;普萘洛尔仅抑制凝血酶诱导的MDA生成.对AA诱导的MDA无影响.MFA0.4mmol·L~(-1)不影响血小板内cAMP含量.结果提示MFA抑制血小板AA代谢通路可能是其抑制血小板聚集功能的机理之一.     

眼镜蛇毒金属蛋白酶atrase A抗血小板聚集作用及机制

目的研究中华眼镜蛇毒金属蛋白酶atrase A对血小板聚集的影响及其相关的机制。方法测定atrase A对二磷酸腺苷、胶原、血小板活化因子、花生四烯酸、瑞斯托霉素、凝血酶诱导血小板聚集的影响情况,并通过蛋白质免疫印迹检测atrase A对血小板膜糖蛋白和血管假血友病因子的酶切情况。结果中华眼镜蛇毒金属蛋白酶atrase A能明显抑制由瑞斯托霉素和凝血酶诱导的血小板聚集,这种抑制作用呈量效、时效关系。而atrase A和血小板预孵5min后对二磷酸腺苷、胶原、血小板活化因子、花生四烯酸诱导的血小板聚集有微弱的抑制作用,预孵时间延长至30min对血小板聚集有明显的抑制作用。蛋白质免疫印迹结果显示atrase A能特异性酶切血小板膜糖蛋白GPIb,但对vWF几乎没有酶切作用。结论中华眼镜蛇毒金属蛋白酶atrase A对二磷酸腺苷、胶原、血小板活化因子、花生四烯酸、瑞斯托霉素、凝血酶诱导的血小板聚集均有抑制作用,其中对瑞斯托霉素和凝血酶诱导的血小板聚集具有明显的抑制作用,其机制是通过酶切血小板膜糖蛋白GPIb。     

Vitamin E and vitamin C inhibit arachidonate-induced aggregation of human peripheral blood leukocytes in vitro

Arachidonate induces aggregation of human polymorphonuclear (PMN) and mononuclear (MNL) blood leukocytes. This is mediated by the lipoxygenase pathway, as it is prevented by lipoxygenase inhibitors and can also be induced by leukotriene B4 (LTB4). Vitamin E and vitamin C have profound effects on the functional state of leukocytes, some of which may involve the lipoxygenase pathway. This study shows that both vitamins inhibit arachidonate-induced aggregation of PMN and MNL, in a concentration-dependent way. BW-755, previously shown to inhibit arachidonate-induced PMN and NML aggregation, was found to potentiate the inhibitory activity of both vitamins. When LTB4 was used as an aggregating agent, vitamin E markedly inhibited PMN and MNL aggregation, whereas vitamin C was ineffective. The prevention of PMN and MNL aggregation by vitamin E might account, at least partially, for the reported beneficial effects of vitamin E supplementation in some experimental syndromes characterized by leukocyte activation.     

The release of leukotriene B4 during experimental inflammation

Leukotriene B4 (LTB4) has been detected by radioimmunoassay in inflammatory exudates obtained following the implantation of saline- or carrageenan-soaked polyester sponges in rats. The immunoreactive material was confirmed as LTB4 after extraction and purification by high pressure liquid chromatography. The peak concentration (6.9 +/- 0.5 ng/ml) was detected 6 hr after implantation of sponges soaked in 0.5% carrageenan; thereafter the level declined and was undetectable after 16-24 hr. The concentration of LTB4 during the early phase of the inflammatory response (4-8 hr) is sufficient to induce leukocyte aggregation, chemotaxis and degranulation of polymorphonuclear leukocytes (PMN) in vitro. Therefore, LTB4 may mediate, at least in part, the influx of PMN and contribute to other events which characterise the inflammatory response. The level of thromboxane B2 (TXB2) in the inflammatory exudate followed a similar time-course to that of LTB4 although the maximum concentration was higher (15-30 ng/ml). However, prostaglandin E2 (PGE2) exhibited a different time-course; the maximum level (20-30 ng/ml) was also reached 6-8 hr after implantation but remained elevated at 24 hr. The PMN count in the sponges and the concentrations of both LTB4 and TXB2, but not PGE2, were significantly reduced by prior treatment of the animals with colchicine. This suggests that PMN are the major source of LTB4 and TXB2 in the inflammatory exudate whereas PGE2 is produced in significant amounts by other tissues.     

Activation of leukotriene synthesis in human neutrophils by exogenous arachidonic acid: inhibition by adenosine A(2a) receptor agonists and crucial role of autocrine activation by leukotriene B(4).

We report here that the apparent inability of isolated human polymorphonuclear leukocytes (PMNs) to efficiently transform arachidonic acid (AA) is the consequence of A(2a) receptor engagement by endogenous adenosine accumulating in incubation media. Indeed, when adenosine is eliminated from PMN suspensions by the addition of adenosine deaminase, or when cells are incubated with adenosine A(2a) receptor antagonists, important quantities (40-80 pmol/10(6) cells) of 5-lipoxygenase products are synthesized by PMN incubated with 1 to 5 microM exogenous AA. The selective A(2a) receptor agonist CGS21680 was a very potent inhibitor of the AA-induced leukotriene (LT) synthesis, showing an IC(50) of approximately 1 nM. The mechanism of AA-induced stimulation of LT synthesis observed in the absence of extracellular adenosine was investigated. In adenosine deaminase-treated PMN, exogenous AA induced Ca(2+) mobilization and the translocation of 5-lipoxygenase to nuclear structures. A time lag of 20 to 60 s (variable between PMN preparations) was observed consistently between the addition of AA and the elevation of intracellular Ca(2+) concentration (and LT synthesis), indicating that AA itself did not trigger the Ca(2+) mobilization in PMN. This AA-induced Ca(2+) mobilization, as well as the corresponding 5-lipoxygenase translocation and stimulation of LT synthesis, was blocked efficiently by the LT synthesis inhibitor MK0591, the LTB(4) receptor antagonists CP105696 and LY223982, and the LTA(4) hydrolase inhibitor SC57461A. These data demonstrate that AA is a highly potent and effective activator of LT synthesis and acts through a mechanism that requires an autocrine stimulatory loop by LTB(4).     

广西眼镜蛇毒细胞毒素的分离及对人鼻咽癌等细胞抑制作用的研究

目的　探讨广西眼镜蛇毒细胞毒素对人鼻咽癌细胞(CNE)等多种癌细胞株的抑制作用。方法　经SephadexG 5 0 ,CM SepharoseCL 6B层析法从广西眼镜蛇毒中分离纯化获得细胞毒素 (CTX) ,采用MTT检测CTX对癌细胞株体外培养抑制作用 ,探索量效时效关系。结果　从广西眼镜蛇毒中分离到一种细胞毒素单一组分 (CTXCM 5 )对体外培养的人鼻咽癌细胞株 (CNE)、淋巴瘤细胞株 (YAC)、人宫颈癌细胞株 (HELA)和卵巢癌细胞株 (Ho8990 )的抑制有明显的剂量依赖关系 ,作用 48h的IC50 分别为 1 84,0 75 ,1 84和 2 5 9mg·L-1;随作用时间的延长 ,CTXCM 5对CNE细胞株作用最为明显 ,作用 3h和 2 4h的IC50 分别为 4 78和1 0 4mg·L-1。结论　CTXCM 5对体外培养的癌细胞株有较强的抑制作用。     

Antiplatelet effects of policosanol (20 and 40 mg/day) in healthy volunteers and dyslipidaemic patients

1. The present study was undertaken to compare the effects of a higher dose of policosanol, a cholesterol-lowering drug, (40 mg/day) with the effects of 20 mg/day policosanol on platelet aggregation in healthy volunteers and type II hypercholesterolaemic patients. 2. Study subjects were randomized to receive, under double-blind conditions, placebo or policosanol (20 or 40 mg/day) for 30 days once a day. Blood sampling was performed at baseline and after 30 days on therapy. 3. Platelet aggregation was induced with three aggregating agents: arachidonic acid (AA), collagen and low doses of ADP. 4. Policosanol (20 and 40 mg/day) moderately yet significantly reduced platelet aggregation, but no differences were observed in the effects produced by either dose of policosanol. In healthy volunteers, policosanol at 20 and 40 mg/day inhibited aggregation induced by 2 mmol/L AA (28.2 and 24.9%, respectively), 1 micro g/mL collagen (21.1 and 20.2%) and 1 micro mol/L ADP (30.9 and 29.1%). Changes that occurred following the administration of placebo were not significant, although an upward trend for collagen- and ADP-induced aggregation occurred in normal and hypercholesterolaemic subjects, respectively, thus partially masking the effects of policosanol on these responses. 5. The antiplatelet effects of policosanol at 20 and 40 mg/day in hypercholesterolaemic patients were also similar, so that both doses inhibited aggregation induced by 1.5 mmol/L AA (20.1 and 33.0%, respectively), 0.5 micro g/mL collagen (22.7 and 21.1%) and 1 micro mol/L ADP (40.5 and 34.7%). 6. In addition, after 30 days of therapy, 20 and 40 mg/day policosanol significantly (P < 0.01) reduced low-density lipoprotein-cholesterol (15.9 and 17.0%, respectively) and total cholesterol (12.4 and 12.3%, respectively; P < 0.05), yet increased high-density lipoprotein-cholesterol values by 5% in both groups (P < 0.05). 7. Triglycerides were decreased compared with baseline, but not with respect to the placebo. 8. We conclude that the antiplatelet effects induced by 40 mg/day policosanol administered for 30 days to healthy volunteers and to hypercholesterolaemic patients were similar to the effects induced by 20 mg/day policosanol. Thus, no enhancement of the response was achieved with the use of a higher dose of policosanol in study patients.