氯吡格雷联合奥扎格雷钠对急性缺血性卒中患者血小板CD62p、CD63的影响

目的评价氯吡格雷联合奥扎格雷钠治疗急性缺血性卒中的疗效。方法选取我院神经内科于2012-08—2013-08收治的120例急性缺血性卒中患者为研究对象,随机分为观察组与对照组。观察组60例给予氯吡格雷联合奥扎格雷钠治疗,对照组60例给予阿司匹林治疗。治疗结束后对比2组患者血小板CD62p、CD63表达情况、NIHSS评分及疗效。结果2组患者治疗前后的CD62p、CD63表达阳性率及NIHSS评分均无显著差异(P0.05)。观察组治疗总有效率95.00%,对照组96.67%,2组比较差异无统计学意义(P0.05)。结论抗血小板药物治疗急性缺血性卒中疗效肯定,且与阿司匹林疗效无差异,CD62p、CD63蛋白可以有效反映血小板活化情况。     

氯吡格雷与阿司匹林联合应用在急性脑梗死治疗中的疗效评定

目的观察急性脑梗死患者血小板上α颗粒膜糖蛋白(CD62p)及溶酶体颗粒膜糖蛋白(CD63)的表达,通过血小板活化的变化,探讨阿司匹林与氯吡格雷联合用药与阿司匹林单药治疗的疗效差异。方法将60例脑梗死患者随机分为两个亚组:单药组(阿司匹林0.15 g/d)和联合用药组(阿司匹林0.10 g/d+氯吡格雷75 mg/d),30例健康体检者为对照组。使用流式细胞术检测所有病例CD62p、CD63阳性率,对单药组和联合用药组治疗前后的CD62p、CD63阳性率进行比较,同时进行NIHSS评分。结果脑梗死组血小板CD62p、CD63阳性率显著高于对照组(P<0.01)。单药组和联合用药组在治疗一周和二周后CD62p、CD63阳性率和NIHSS评分均较治疗前显著下降(P<0.01)。联合用药组治疗二周后与单药组比较CD62p、CD63阳性率和NIHSS评分明显降低,差异有统计学意义(P<0.01)。结论抗血小板治疗对脑梗死有效,阿司匹林+氯吡格雷联合治疗的总体疗效明显优于单用阿司匹林,CD62p、CD63可以衡量抗血小板治疗效果。     

奥扎格雷对急性脑梗死患者血小板CD62p和CD63表达的影响及其疗效

目的观察奥扎格雷对急性脑梗死(ACI)患者血小板CD62p、CD63表达的影响及其疗效。方法将64例ACI患者随机分为奥扎格雷治疗组和血塞通治疗组(对照组),采用流式细胞术检测ACI患者治疗前后及正常人(正常组)血小板CD62p、CD63的表达;观察奥扎格雷治疗组和对照组的临床疗效并进行比较。结果ACI患者血小板CD62p、CD63表达水平明显高于正常组(均P<0.01);奥扎格雷治疗组与对照组治疗后血小板CD62p、CD63表达水平较治疗前均有明显下降(P<0.05～0.01),奥扎格雷治疗组又明显低于对照组,差异有显著性(均P<0.05)。奥扎格雷治疗组的基本痊愈率、显著进步率、总有效率明显高于对照组(均P<0.05)。结论ACI发病后血小板CD62p、CD63表达水平显著增高;奥扎格雷有明显抑制血小板表达CD62p、CD63的作用,对ACI的治疗效果显著。     

奥扎格雷对进展性脑血栓形成患者血小板活化功能变化的影响

目的：探讨奥扎格雷对进展性脑血栓形成患者血小板活化功能变化的影响。方法：68例颈内动脉系统进展性脑血栓形成患者随机分为奥扎格雷治疗组和丹参治疗组。应用流式细胞仪和单克隆抗体动态测定CD62p、CD63，行血小板活化指标和临床疗效对照观察。结果：进展性脑血栓形成患者发病早期（24h内）CD62p、CD63值较对照组显著增高（P〈0．001）。患者经丹参治疗后，血小板表达CD62p、CD63缓慢下降，14d时其值仍高于健康对照组（P〈0．05）。经奥扎格雷治疗后血小板表达CD62p、CD63快速下降，至14d时已接近健康对照组（P〉0．05）。奥扎格雷组临床疗效明显优于丹参组。结论：进展性脑血栓形成患者中血小板表达CD62p、CD63明显增加，并与病情转归相关。奥扎格雷治疗后可使CD62p、CD63快速下降、提高临床疗效。     

氯吡格雷联合阿司匹林在急性脑梗死治疗中的疗效评定

目的探讨氯吡格雷联合阿司匹林在急性脑梗死治疗中的临床疗效。方法将80例急性脑梗死患者按照随机数字表法分为2组,对照组40例给予阿司匹林治疗,观察组在对照组治疗的基础上加用氯吡格雷治疗,治疗2周后比较2组临床疗效、神经功能缺损评分、血小板抑制率及溶酶体颗粒膜糖蛋白(CD63)、α颗粒膜糖蛋白(CD62P)表达水平。结果观察组临床疗效显著优于对照组,差异有统计学意义(Z=2.159,P0.05);治疗第1、2周时,观察组神经功能缺损评分及CD63、CD62P表达水平均低于对照组,AA、ADP均高于对照组,差异有统计学意义(P0.05)。结论氯吡格雷与阿司匹林联合应用提高了急性脑梗死患者临床疗效和神经功能,抑制了血小板聚集和血小板活化,值得临床重视。     

TIA患者血小板活化功能的变化及奥扎格雷对其影响

目的 探讨TIA患者血小板活化功能的变化及奥扎格雷对其影响.方法 应用流式细胞仪和单克隆抗体技术测定丹参治疗组和奥扎格雷治疗组不同时段的颗粒膜蛋白140(CD62p)、溶酶体整合膜糖蛋白(CD63)值.结果 TIA患者血小板表达CD62p、CD63明显增高,经奥扎格雷治疗后CD62p、CD63快速下降,较丹参治疗组有显著差异(P<0.01).结论 血小板表达CD62p、CD63在TIA患者中明显增强,并与病情转归相关;奥扎格雷干预治疗可使CD62p、CD63快速下降,提高治疗的有效率.     

氯吡格雷、阿司匹林及低分子肝素钙联合治疗急性脑梗死疗效观察

目的探讨氯吡格雷、阿司匹林及低分子肝素钙联合治疗急性脑梗死的疗效和安全性。方法 60例急性脑梗死患者随机分为氯吡格雷、阿司匹林及低分子肝素钙治疗组(联合治疗组A组)30例和阿司匹林及低分子肝素钙治疗组(常规治疗组B组)30例,观察用药前后的疗效、安全性,血小板活化状态及测定神经功能缺损评分。结果治疗组于治疗后14d,神经功能缺损评分较治疗前明显下降(P0.01),与对照组比较差异有统计学意义(P0.05),治疗组显效率明显优于对照组(P0.01),血小板活化指标(CD63、CD62P)治疗后14d联合治疗组血小板活化指标明显下降,2组差异有统计学意义(P0.05)。结论在阿司匹林及低分子肝素钙基础上加用氯吡格雷有助于神经功能恢复,疗效好,未见出血增加,值得推广应用。     

依达拉奉联合奥扎格雷钠治疗超溶栓时间窗急性缺血性卒中临床观察

观察依达拉奉联合奥扎格雷钠治疗超溶栓时间窗的急性缺血性卒中患者的临床疗效.结果显示,治疗14d后依达拉奉联合奥扎格雷钠组(联合治疗组)患者治疗总有效率达92％(46/50),高于奥扎格雷钠单药治疗组的66％(33/50;x2=10.780,P=0.029);两组患者神经功能明显改善,但联合治疗组[(8.21 +3.58)分]优于奥扎格雷单药治疗组[(14.60±4.39)分;t=7.976,P=0.000].提示对于超溶栓时间窗的急性缺血性卒中患者,依达拉奉联合奥扎格雷钠仍可改善神经功能,临床疗效确切.     

用血栓弹力图评价阿司匹林及氯吡格雷在缺血性卒中患者中血小板抑制效应的研究

目的用血栓弹力图评价缺血性卒中患者正规使用阿司匹林及氯吡格雷后血小板抑制率的变化。方法血栓弹力图检测我院123例住院患者抗血小板药物治疗后花生四烯酸(AA)通路和ADP受体途径诱导的血小板抑制率,患者抗血小板药物治疗包括阿司匹林组(n=7)、氯吡格雷组(n=8)、阿司匹林+氯吡格联合组(n=108)。结果 123例患者中,阿司匹林组AA诱导的血小板抑率为(87.04±22.71)%,氯吡格雷组ADP诱导的血小板抑制率平均值为(46.61±24.43)%,阿司匹林+氯吡格雷组AA和ADP诱导的血小板抑制率为分别(77.87±27.98)%和(50.23±29.27)%。服用阿司匹林和氯吡格雷的患者分别有115和116例,其AA和ADP途径血小板抑制率分别为(78.42±27.69)%;(49.99±28.88)%,差异具有显著统计学意义(P=0.000)。其中对阿司匹林和氯吡格雷敏感者(血小板抑制率≥50%)分别为97例(84.34%)和89例(75.72%),而不敏感者(血小板抑制率<50%)分别为18例(15.65%)和27例(23.28%),两种药物疗效间差异无显著统计学意义(χ2=3.706,P=0.054)。结论服用100mg/d阿司匹林,在绝大多数缺血性脑血管病患者中能产生较强的血小板抑制效应,而服用75mg/d氯吡格雷对血小板抑制稍弱,但多数患者仍能达有效的血小板抑制作用。     

氯吡格雷治疗短暂性脑缺血发作的疗效观察

目的分析氯吡格雷应用于短暂性脑缺血发作(TIA)患者中的临床疗效。方法 TIA患者共100例随机分为实验组和对照组。对照组予以拜阿司匹林+阿托伐他汀钙治疗,实验组在对照组基础上加用泰嘉(氯吡格雷)治疗。对比2组治疗6个月后的血脂和血小板活化指标水平,同时对比2组治疗1a内的脑血管事件发生率。结果 2组治疗后的总胆固醇、甘油三酯和LDL水平显著低于治疗前,HDL水平显著高于治疗前(P0.05);实验组治疗后的总胆固醇、甘油三酯和LDL水平显著低于对照组,HDL水平显著高于对照组(P0.05)。2组治疗后的CD62p和CD63水平均显著低于治疗前(P0.05);实验组治疗后的CD62p和CD63水平均显著低于对照组(P0.05),1a内再次TIA脑出血、脑梗死发生率均低于对照组(P0.05)。结论氯吡格雷治疗TIA疗效满意,值得临床推广。     

The importance of blood collection methods for assessment of platelet activation

Blood collection and processing techniques must be carefully standardized in order to make valid measurements of plasma concentrations of platelet secreted proteins. We therefore conducted this study to determine the optimum method for obtaining serial blood samples for platelet factor 4 (PF4) radioimmunoassay and circulating platelet aggregate ratios (CPA). Venous blood samples for PF4 and CPA were obtained from normal volunteers through either an indwelling 21 guage butterfly needle or by multiple separate venipunctures using the same type of needle and a modified “two-syringe” technique. Results demonstrated that there was significant platelet activation and secretion of PF4, but not CPA, that occurred within 15 minutes of needle insertion and continued during the duration of time that samples were obtained through the indwelling needle. Although there were lower plasma PF4 concentrations if a high fluid flow rate was maintained, there was still a significantly higher PF4 concentration when compared to samples obtained simultaneously by single venipuncture in the opposite arm. In addition, these results demonstrated that neither an indwelling intravenous needle in the opposite arm nor a previous venipuncture in the same site elevated PF4 concentrations.     

A comparison of three platelet function tests in ischemic stroke patients with antiplatelet therapy

Predicting the effectiveness of antiplatelet drugs is critical to precision antiplatelet therapy. However, there is a lack of an acceptable method, although there are a variety of methods for detecting platelet function. In this study, we compared three major platelet function tests to assess their performance and found better methods for platelet function evaluation after aspirin or clopidogrel treatment in ischemic stroke patients by comparative study. A total of 249 ischemic stroke patients were enrolled who were treated with aspirin or clopidogrel or both. Three platelet function tests including light transmittance aggregometry (LTA), thromboelastography (TEG), platelet function analyzer (PFA) were performed as well as CYP2C19 genotype determination. Correlation analyses and kappa statistics were used. All three methods were effective in evaluating aspirin function. However, only LTA and TEG had good correlation and consistency (r = -0.37, kappa = 0.634). TEG-ADP was the least sensitive for clopidogrel, as the platelet inhibition ratio did not differ between the clopidogrel-user group and the control (P = 0.074), while LTA and PFA were sensitive (P ＜ 0.001). Correlations between platelet assays were poor for clopidogrel (the absolute value of r range from 0.13 to 0.35) and so was the agreement (Kappa from 0.232 to 0.314). LTA and PFA have a good correlation with CYP2C19 genotyping (P = 0.034 and 0.014). In conclusion, all three tests were able to evaluate aspirin effect, LTA-AA and TEG-AA had a good correlation. TEG perform badly for clopidogrel effect detection. The fair-to-modest agreement among assays indicated further study was indispensable.     

Arginyl-glycyl-aspartyl (RGD) epitope of human apolipoprotein (a) inhibits platelet aggregation by antagonizing the IIb subunit of the fibrinogen (GPIIb/IIIa) receptor

An unknown epitope of apolipoprotein (a) antagonizes fibrinogen binding to agonist-stimulated platelet's fibrinogen (GPIIb/IIIa) receptor yielding lipoprotein (a) mediated decreased platelet aggregation. The purpose of this study was to test the hypothesis that human apolipoprotein (a)'s single arginyl-glycyl-aspartyl (RGD) epitope, unique to apolipoprotein (a) in lipoprotein (a) binds to the RGD binding motif on the IIb subunit of the GPIIb/IIIa receptor thus reducing platelet-bound fibrinogen and consequently decreasing agonist-stimulated platelet aggregation. Platelets (N=30 subjects) were prepared from fresh plasma, washed three times in Tyrode's buffer and stimulated using 10 microM ADP or 2 microg/ml collagen. Lipoprotein (a) was isolated from plasma using lectin affinity chromatography followed by ultracentrifugation. The peptide RGDS inhibited (125)I-labelled lipoprotein (a) binding to autologous platelets with IC-50's of 25.1+/-2.2 (mean+/-SEM) and 15.4+/-1.3 microM for collagen- and ADP-stimulation respectively. Further, RGDS reduced platelet binding of (125)I-labelled fibrinogen IC-50's of 35.5+/-3.2 (mean+/-SEM) and 20.7+/-2.2 microM for collagen- and ADP-stimulation respectively. The monoclonal antibody PAC-1, uniquely directed at the RGD binding motif on the IIb subunit on collagen- and ADP-stimulated platelets, inhibited binding of (125)I-labelled lipoprotein (a) with IC-50's of 6.4+/-0.7 and 2.5+/-2.2 microg/10(8) platelets for collagen- and ADP-stimulation respectively. Additionally, PAC-1 reduced platelet bound of (125)I-labelled fibrinogen with IC-50's of 9.0+/-1.4 and 4.1+/-2.2 microg/10(8) platelets for collagen- and ADP-stimulation respectively. In a dose-related fashion, a polyclonal antibody, specific for the RGD epitope on apolipoprotein (a), restored platelet aggregation to control levels, inhibited (125)I-labelled lipoprotein (a) binding, and increased (125)I-labelled fibrinogen by displacing lipoprotein (a) from the GPIIb/IIIa receptor. Thus a never before demonstrated aspect of the mechanism of lipoprotein (a)'s suggested novel role as an endogenous regulator of fibrinogen binding to collagen- and ADP-stimulated platelets has been shown. In conclusion, lipoprotein (a), via apolipoprotein (a)'s RGD epitope, binds to the RGD binding motif on the IIb protein of the GPIIb/IIIa receptor consequently reducing platelet-bound fibrinogen which results in decreased platelet aggregation.     

Modified forms of low density lipoprotein affect platelet aggregation

Modified forms of low density lipoprotein (LDL) unlike native LDL can lead to macrophage cholesterol accumulation and foam cell formation. Since platelets interact with both lipoprotein and macrophages in the atherosclerotic plaque, the present study was designed to analyze the effect of modified LDL on washed human platelet composition and aggregation. Platelet aggregation was increased following 2 h of incubation with native LDL. Phospholipase C modified LDL and hepatic lipase modified LDL but not acetyl LDL further increased collagen induced platelet aggregation in a dose dependent manner by up to 15% (p less than 0.01). Oxidized LDL, however, demonstrated 25% reduction in both collagen and ADP induced platelet aggregation in comparison to the effect of native LDL. Platelet aggregation was found to be directly related to changes in platelet phospholipid content whereas platelet cholesterol content was similarly affected by all lipoproteins. Platelet cholesterol/phospholipid ratio was directly related to platelet aggregation. Our study thus demonstrates that modified forms of LDL significantly affect platelet lipid composition and function and if similar interactions occur in vivo it might also affect the atherogenic process.     

Low platelet monoamine oxidase activity: A possible biochemical correlate of borderline schizophrenia

Platelet monoamine oxidase (MAO) activity, psychiatric disorders, and family history of psychopathology were studied in 115 nonhospitalized, previously undiagnosed college student volunteers. Subjects were classified into two extreme groups: those with platelet MAO activity two standard deviations below the mean (“low-MAO” probands) and those with platelet MAO activity two standard deviations above the mean (“high”-MAO probands). Low-MAO probands were found to have a significant increase in the incidence of borderline schizophrenia and other psychiatric disorders compared to high-MAO probands. First-degree relatives of low-MAO probands were more often affected with psychiatric disorders and borderline schizophrenia than relatives of high-MAO probands. The data suggest that reduced platelet MAO activity is associated with psychiatric vulnerability and that the spectrum of schizophrenia may be more closely related to this vulnerability than other psychiatric disorders.     

Physiological changes in membrane-expressed platelet factor 4: Implications in heparin-induced thrombocytopenia

Background

Many heparin-induced thrombocytopenia (HIT) antibodies cause platelet activation in the serotonin release assay (SRA) in the absence of heparin. This in vitro observation may help unravel the mechanism of delayed-onset HIT, where seropositive patients develop thrombocytopenia and associated thrombosis after cessation of heparin.

Objective

Studies were conducted to examine the relationship between platelet environment, surface PF4 expression, and the extent of heparin-independent platelet activation in the SRA.

Methods

Ex vivo platelets were washed and labeled for SRA, then used either before or after 45 minutes of recovery at 37 °C. HIT antibody-mediated serotonin release in the absence of heparin was compared to the extent of surface staining of the platelets with fluorescent anti-human PF4 antibodies.

Results

Handling of platelets for in vitro studies resulted in transient expression of surface PF4, and it was during this interval that platelets were most sensitive to activation by HIT antibodies in the absence of heparin. Heparin-independent platelet activation was attenuated when SRA-positive specimens were retested after platelets were incubated 45 minutes at 37 °C. Surface PF4 expression was diminished on the rested platelets, compared to the same platelets labeled immediately after handling. Thus compared to rested platelets, mildly activated platelets had elevated surface PF4 expression and a higher level of HIT antibody-mediated, heparin-independent platelet activation.

Conclusion

Surface expression of PF4 reflects HIT antigen presentation, and varies with the physiological state of platelets. Thus there can be differences in HIT antibody target availability among patients which may explain the variability in consequences of HIT antibody seropositivity.     

A double antibody sandwich microELISA for measuring human platelet factor 4

With the aim of investigating patients with a higher risk of thrombosis we developed a method for determining platelet factor 4 (PF4) in human plasma. Using the double antibody sandwich ELISA technique we set up a test system that allows the determination of PF4 concentrations in plasma samples from 1 to 100 ng/ml. This method is more sensitive and as specific as commercially available RIA kits, but has the advantage of being cheaper and less time consuming. Furthermore the ELISA does not require radioactive materials. The complete reaction is carried out in microtiter wells, and an ELISA-reader connected to an Apple computer does all the calculations needed for quantitative measurements.     

Platelet activation during treadmill exercise in patients with chronic peripheral arterial disease

β-Thromboglobulin (β-TG) and platelet factor 4 (PF-4) were measured in 59 patients with chronic peripheral arterial disease before and within 5 min. after treadmill exercising till occurrence of claudication. Plasma levels of β-TG before treadmill exercise ranged from 24 to 260 ng/ml with a geometric mean of 63.7 ng/ml, PF-4 levels ranged from 2 to 240 ng/ml with a mean of 18.5 ng/ml. These levels were significantly higher than those obtained in 28 normal individuals in which β-TG ranged from 7 to 39 ng/ml with a geometric mean value of 19.4 ng/ml and PF-4 from 1 to 19 ng/ml with a mean value of 4.6 ng/ml. No correlation between plasma β-TG or PF-4 and extent of arterial disease was found. β-TG levels, measured within 5 min. after treadmill exercise, showed a statistically significant increase to a mean value of 74.3 ng/ml but PF-4 did not rise significantly (mean value : 19.8 ng/ml) The supplementary increase of already elevated β-TG levels may be explained by enhanced in vivo platelet activation during treadmill exercising till occurrence of claudication. As the clearance of PF-4 from human plasma has been shown to be much faster than the clearance of β-TG, increases in PF-4 levels may be more difficult to detect during dynamic explorations of the vascular system.     

A novel platelet-activating protein derived from rat submandibular glands

Among the various naturally occurring substances which induce platelet aggregation and secretion, considerable attention has been focused recently on the phospholipid platelet-activating factor (PAF) derived from a variety of mammalian cells. In this report, we describe a platelet-activating protein, designated RS-PAP, which was isolated and partially purified from the submandibular salivary glands of adult male rats. This material caused a dose-related in vitro activation of washed, [3H]serotonin-labeled platelets from rats, rabbits and humans. The biologic activity of RS-PAP was compared with that of 1-0-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine (AGEPC), a well-characterized representative of the phospholipid platelet-activating factors, and collagen, a potent platelet-stimulating protein. The activation of washed rabbit platelets by RS-PAP required extracellular calcium for both aggregation and secretion of [3H]serotonin, and was not inhibited by indomethacin. Furthermore, RS-PAP was not inhibited by pretreatment with phenylmethylsulfonyl fluoride, iodoacetate, hirudin or an acetylhydrolase which specifically degrades the phospholipid AGEPC. RS-PAP was completely inactivated by heating at 56 degrees C for 20 minutes, by trypsinization and by a phospholipid extraction procedure. Gel filtration on Sephacryl S-200 indicated an approximate molecular weight of 22,000 - 25,000 daltons. Thus RS-PAP appears to be a new platelet-stimulating protein which activates a variety of mammalian platelets.