前循环进展性脑梗死患者颈动脉硬化分析及血小板CD62p表达

目的分析前循环进展性脑梗死患者颈动脉硬化及血小板活化功能;并探讨颈动脉斑块性质与血小板活化关系。方法选择急性前循环脑梗死患者110例,根据病情分为进展组56例和非进展组54例;另选健康体检者40例为对照组。采用流式细胞仪测定其血小板活化指标CD62p的表达,同时行颈动脉多普勒超声检查。根据颈动脉斑块性质将脑梗死患者分为无斑块27例、稳定斑块43例和不稳定斑块40例,比较CD62p的表达。结果进展组颈动脉斑块以不稳定斑块为主(44.6%);与对照组比较,进展组和非进展组CD62p明显升高[(17.75±2.26)%vs(10.26±1.87)%vs(4.50±1.15)%,P<0.05];与无斑块患者比较,不稳定斑块和稳定斑块患者CD62p明显升高[(15.28±2.12)%vs(9.09±1.70)%vs(5.23±1.28)%,P<0.05]。结论颈动脉斑块不稳定性、血小板活化指标CD62p与脑卒中进展有关;血小板活化指标CD62p表达的高低与斑块性质相关。     

主动脉弓粥样硬化性病变与缺血性卒中

由于检测技术的局限和医生认识的不足,人们公认的常见栓子来源仍为心源性栓子、颈动脉和椎动脉病变,而对主动脉弓粥样硬化病变这一重要的栓子来源未引起足够重视.文章简要阐述了主动脉弓粥样硬化性病变的特征、检测方法及其与缺血性卒中风险的相关性.     

脑梗死患者P-选择素和细胞间粘附分子-1表达改变及其意义

目的 探讨缺血性脑卒中患者P-选择素（CD62P）和血浆中可溶性细胞间粘附分子-1（sICAM-1）表达的规律及其意义。方法 运用酶联免疫吸附测定（ELISA）的方法检测30例脑梗死患者和30名健康对照者CD62P、sICAM-1的表达水平。结果 缺血性脑卒中患者急性期CD62P和sICAM-1表达显著高于其恢复期及健康对照组（均P〈0．01），恢复期CD62P和sICAM-1表达仍高于健康对照组（P〈0．05）。结论CD62P、sICAM-1参与了缺血性脑卒中炎症反应和血小板活化的病理过程，血清CD62P和sICAM-1水平可作为缺血性脑血管病发生发展及病情监测的参考指标。     

脑梗死后血小板CD62p表达的动态变化及抗血小板药物的影响

目的观察脑梗死急性期至恢复期CD62p的动态变化,并探讨抗血小板药物对其影响。方法选择急性脑梗死患者73例作为脑梗死组,并随机分为阿司匹林组(41例)和氯吡格雷组(32例)2个亚组分别进行治疗,同期选择年龄、性别相匹配的非脑血管病患者(高危对照组,20例)及健康体检者(健康对照组,20例),采用流式细胞技术,前2组于发病后<48 h、7、21、90天,另1组体检时对血小板CD62p表达进行检测,并作比较。结果与高危对照组及健康对照组比较,脑梗死组各时间点CD62p表达均显著增加(P<0.01);与<48 h比较,脑梗死组21天和90天时CD62p表达显著下降(P<0.01),但21天与90天比较差异无统计学意义(P>0.05)。90天时,氯吡格雷组CD62p表达显著低于阿司匹林组(P<0.05)。结论脑梗死急性期血小板活化增强,随时间延长,CD62p表达逐渐下降;氯吡格雷较阿司匹林具有更强的抑制CD62p表达作用。     

Role of platelet P-selectin and CD40 ligand in the induction of monocytic tissue factor expression

Activated platelets can express CD40 ligand (CD40L) and trigger inflammatory response and tissue factor (TF) expression in endothelial cells through interaction with CD40. This pathway is also important for T cell-induced monocyte and endothelial cell procoagulant activity. We have studied the potential role of the CD40-CD40L pathway in platelet-induced TF expression in a monocytic cell line and in whole-blood monocytes. In vitamin D(3)-differentiated U-937 cells, thrombin-stimulated platelets increased TF expression as measured by mRNA quantification, flow cytometry, and procoagulant activity. Maximum antigen expression occurred after 2 hours. Neutralizing anti-P-selectin antibody yielded a 50% suppression of procoagulant activity, whereas antibody to CD40L had no effect. In thrombin receptor activator-stimulated citrated blood, monocytes were up to 77% TF-positive, with peak expression after only 15 minutes. However, no TF mRNA was detectable at that time. Anti-P-selectin antibody reduced TF by 50%, whereas antibody to CD40L gave a 17% reduction. Thus, we conclude that P-selectin exposed on activated platelets induces the expression of TF in both U-937 cells and whole-blood monocytes but by different mechanisms. Platelet CD40L does not display any significant effect on U-937 cells but may be of some importance on whole-blood monocytes. This suggests a possible functional difference between U-937 and monocyte CD40. Another important finding in this study is the rapid appearance of surface TF on monocytes without detectable mRNA formation. This indicates that TF may be stored intracellularly in these cells and can be exposed on the surface independent of de novo protein synthesis.     

急性脑梗死患者血小板微颗粒水平及血小板聚集率的相关性研究

目的研究急性脑梗死(acute ischemic stroke,AIS)患者血清血小板微颗粒(platelet microparticle,PMP)和血小板聚集率(platelet aggregation rate,PAG)与脑梗死预后的关系。方法连续收集2015年1月~2016年1月在我院接受治疗的102例患者,其中男性56例,女性46例,平均年龄(67.81±5.68)岁。AIS组62例,对照组为40例。结果 AIS组PMP[(6.11±1.54)%vs(2.31±0.83)%,P=0.000]和PAG[(81.66±7.15)%vs(57.36±7.98)%,P=0.000]水平较对照组均明显升高。AIS组治疗2周后PMP[(4.28±1.31)%vs(6.11±1.54)%,P=0.000]和PAG[(68.78±7.49)%vs(81.66±7.15)%,P=0.000]水平均较治疗前明显下降。AIS组患者PMP与PAG水平呈显著正相关(r=0.263,P=0.037)。logistic分析显示,年龄、PMP、PAG、TC、空腹血糖与AIS预后相关。结论 PMP和PAG可作为检测判断AIS治疗效果及脑梗死预后的指标。     

急性缺血性脑卒中患者血小板膜糖蛋白的表达

目的　探讨急性缺血性脑卒中患者血小板膜糖蛋白（ＧＰ）的表达与临床伤残严重程度的关系。　方法　用流式细胞术测定５７ 例急性缺血性脑卒中患者血小板膜ＧＰⅡｂ－Ⅲａ复合物的α亚单位（ＣＤ４１）、Ｐ－选择素（ＣＤ６２ｐ）和ＧＰ５３（ＣＤ６３）的表达。　结果　中型卒中患者ＣＤ４１、ＣＤ６２ｐ、ＣＤ６３的表达分别为（６３．０８±１５．０１）％ 、（３．９３±２．７５）％ 、（２．９１±１．４９）％ ,重型患者为（６９．９２±１８．４６）％ 、（４．３２±１．８０）％ 、（３．６１±１．８１）％ ,均明显高于轻型的（４７．５２±１７．０２）％ 、（１．８８±０．７４）％ 、（１．７９±１．４１）％ （均为Ｐ＜ ０．０５）;ＣＤ４１、ＣＤ６２ｐ、ＣＤ６３的表达相互间均呈正相关。　结论　缺血性脑卒中患者急性期血小板膜ＧＰ升高,且与病情的严重程度有关     

颅内动脉粥样硬化性狭窄与急性脑梗死进展发生的关系

目的探讨脑动脉粥样硬化性狭窄与急性脑梗死进展发生的联系。方法回顾性分析2011年1月²014年1月在我院住院治疗的急性单发皮质下小梗死患者272例,根据入院3d是否发生进展性神经功能障碍(PND)分为PND组64例,非PND组208例。所有患者神经功能评估采用美国国立卫生研究院卒中量表(NIHSS)评分,以入院3d内复评NIHSS评分,入院时增加≥2分或运动功能缺损波动≥1分为PND。根据脑血管检查结果将入组患者的脑血管动脉粥样硬化病变分为颅内、颅外及前、后循环系统,比较2组患者间各系统动脉粥样硬化性狭窄发生的差异。结果与非PND组比较,PND组女性比例明显升高(45.3%vs 31.7%,P=0.046)、NIHSS评分明显升高[7(4,9)分vs 6(3,8)分,P=0.033]、病灶≥15mm比例更高(42.2%vs 28.8%,P=0.045)、颅内动脉粥样硬化性狭窄(45.3%vs 29.8%,P=0.022)和颅外动脉粥样硬化性狭窄比例更高(53.1%vs 38.0%,P=0.032),差异有统计学意义。logistic回归分析显示,颅内动脉粥样硬化性狭窄是PND发生的独立危险因素(OR=1.961,95%CI:1.0702014年1月在我院住院治疗的急性单发皮质下小梗死患者272例,根据入院3d是否发生进展性神经功能障碍(PND)分为PND组64例,非PND组208例。所有患者神经功能评估采用美国国立卫生研究院卒中量表(NIHSS)评分,以入院3d内复评NIHSS评分,入院时增加≥2分或运动功能缺损波动≥1分为PND。根据脑血管检查结果将入组患者的脑血管动脉粥样硬化病变分为颅内、颅外及前、后循环系统,比较2组患者间各系统动脉粥样硬化性狭窄发生的差异。结果与非PND组比较,PND组女性比例明显升高(45.3%vs 31.7%,P=0.046)、NIHSS评分明显升高[7(4,9)分vs 6(3,8)分,P=0.033]、病灶≥15mm比例更高(42.2%vs 28.8%,P=0.045)、颅内动脉粥样硬化性狭窄(45.3%vs 29.8%,P=0.022)和颅外动脉粥样硬化性狭窄比例更高(53.1%vs 38.0%,P=0.032),差异有统计学意义。logistic回归分析显示,颅内动脉粥样硬化性狭窄是PND发生的独立危险因素(OR=1.961,95%CI:1.070³.592,P=0.029)。结论颅内动脉粥样硬化性狭窄是急性缺血性脑卒中早期发生PND的独立危险因素。     

CD63 is an essential cofactor to leukocyte recruitment by endothelial P-selectin

The activation of endothelial cells is critical to initiating an inflammatory response. Activation induces the fusion of Weibel-Palade Bodies (WPB) with the plasma membrane, thus transferring P-selectin and VWF to the cell surface, where they act in the recruitment of leukocytes and platelets, respectively. CD63 has long been an established component of WPB, but the functional significance of its presence within an organelle that acts in inflammation and hemostasis was unknown. We find that ablating CD63 expression leads to a loss of P-selectin-dependent function: CD63-deficient HUVECs fail to recruit leukocytes, CD63-deficient mice exhibit a significant reduction in both leukocyte rolling and recruitment and we show a failure of leukocyte extravasation in a peritonitis model. Loss of CD63 has a similar phenotype to loss of P-selectin itself, thus CD63 is an essential cofactor to P-selectin.     

Soluble CD40 ligand, platelet surface CD40 ligand, and total platelet CD40 ligand in atrial fibrillation: relationship to soluble P-selectin, stroke risk factors, and risk factor intervention

BACKGROUND: Abnormal levels of soluble CD40 ligand (sCD40L) have been reported in patients with hypertension, coronary artery disease, diabetes mellitus, heart failure, and stroke, all of which are conditions that are associated with nonvalvular atrial fibrillation (AF). We hypothesized the following: (1) CD40 ligand (CD40L)-related indexes (ie, platelet surface expressed CD40L, the soluble fragment of CD40L [sCD40L], and the total amount of CD40L per platelet [pCD40L]) are elevated in patients with AF compared to control subjects; (2) these indexes correlate with soluble P-selectin (sP-selectin), which is an established platelet marker; and (3) these indexes differentiate "high-risk" from "low-risk" subjects. METHODS: We performed a case-control study of 121 AF patients, 71 "disease control subjects," and 56 "healthy control subjects." Peripheral venous levels of platelet surface-expressed CD40L were analyzed by flow cytometry, while levels of sCD40L, pCD40L, and sP-selectin were measured by enzyme-linked immunosorbent assay. RESULTS: AF patients had significantly higher sCD40L levels compared to healthy control subjects (p = 0.042), with no difference in platelet surface CD40L and pCD40L levels. A positive correlation was noted between levels of sCD40L and pCD40L, and not with sP-selectin. CD40L-related indexes failed to distinguish between high-risk and low-risk AF patients. AF patients receiving optimal antithrombotic therapy had significantly lower pCD40L levels (p < 0.001) compared to control subjects. Optimized AF management also resulted in significant reductions in the levels of sCD40L (p = 0.023) and pCD40L (p < 0.001). CONCLUSION: CD40L-related indexes are not useful in the risk stratification of AF patients, and abnormal sCD40L levels can be reduced by intense multifactorial risk management. While there is a significant, albeit modest, excess of platelet activation in AF patients (as measured by sCD40L levels) compared to healthy control subjects, this is not in excess of that seen in patients with underlying cardiovascular diseases.     

Aspirin inhibits surface glycoprotein IIb/IIIa, P-selectin, CD63, and CD107a receptor expression on human platelets.

Platelet inhibition after aspirin therapy reduces the risk for the development of acute coronary syndromes. However, the mechanism by which aspirin affect platelets other than by prostaglandin blockade is unclear. We sought to determine the in vitro effects of aspirin on the surface expression of nine platelet receptors using whole blood flow cytometry. Blood from 24 healthy volunteers was incubated for 30 min with 1.8 and 7.2 mg/l phosphate-buffered saline-diluted acetylsalicylic acid in the presence or absence of apyrase. Platelet serotonin release, and the surface expression of platelet receptors with or without apyrase were determined using the following monoclonal antibodies: anit-CD41 [glycoprotein (GP)IIb/IIIa], CD42b (GPIb), CD62p (P-selectin), CD51/CD61 (vitronectin receptor), CD31 [platelet/endothelial cellular adhesion molecule-1 (PECAM-1)], CD107a [lysosomal associated membrane protein (LAMP)-1], CD107b (LAMP-2), CD63 (LIMP or LAMP-3), and CD151 (PETA-3). Samples were then immediately fixed with 2% paraformaldehyde, and run on the flow cytometer within 48 h. Aspirin does not affect serotonin release from human platelets. Dose-dependent inhibition of GPIIb/IIIa, P-selectin, CD63, and CD107a receptor expression was observed in the aspirin-treated whole-blood samples. Apyrase potentiates the effects of aspirin, and independently inhibits PECAM-1. In addition to the known effect of irreversibly inhibiting platelet cyclooxygenase-1, thereby blocking thromboxane A(2) synthesis, it appears that aspirin exhibits direct effects on selective major platelet receptors.     

Elevated platelet P-selectin expression and platelet activation in high risk patients with uncontrolled severe hypertension

BACKGROUND: Uncontrolled severe hypertension is associated with alarming rates of cardiovascular events but the mechanisms of vascular injury are not well understood. Recent investigative interest has focused on platelet activation and platelet P-selectin (CD62P) as direct mediators of vascular inflammation and injury. We investigated the association of extreme blood pressure (BP) elevation with platelet P-selectin and fibrinolytic markers in high risk patients with severe hypertension. METHODS: Cross-sectional comparison of platelet CD62, tissue plasminogen activator antigen (tPA), and plasminogen activator inhibitor-1 activity (PAI-1) among 3 BP groups: untreated severely hypertensive patients (SHT; n=18), untreated mildly hypertensive patients (MHT; n=19), and normotensive controls (NT; n=16). RESULTS: Platelet CD62 was greatest in SHT (p=0.00008) and showed a strong correlation with both systolic (p=0.0002, r=0.52) and diastolic (p=0.0003, r=0.52) BP. tPA was greater in SHT than MHT or NT (ANOVA; p=0.02) and correlated with diastolic BP but not SBP. PAI-1 did not correlate with either SBP or DBP but was related to body mass index, diabetes, and dyslipidemia. CONCLUSIONS: Platelet CD62 demonstrated a strong and graded association with both systolic and diastolic BP that persisted in the presence of multiple concomitant risk factors. The association of BP with CD62P was stronger than with either PAI-1 or tPA-Ag. Platelet activation and platelet CD62 increase in a BP-dependent manner and this relationship persists at extreme levels of BP. Platelet activation and platelet CD62 may participate in the accelerated target organ injury observed in high risk patients with severe hypertension.     

Detection of platelet microRNA expression in patients with diabetes mellitus with or without ischemic stroke

AimsThe objective of this study was to investigate the role of plasma and platelet microRNAs in the occurrence of ischemic stroke in patients with diabetes mellitus.MethodsmiR-223, miR-146a, miR-495, and miR-107 expression in the plasma and platelets, blood glucose concentration, and platelet activation rate were measured in patients with diabetes mellitus and ischemic stroke, diabetes mellitus only, ischemic stroke only, and healthy controls. Platelet activity was measured by flow cytometric measurement of P-selectin expression, while miRNA was measured by real-time PCR.ResultsThe expressions of platelet and plasma miR-223 and miR-146a were significantly downregulated in patients with ischemic stroke and diabetes mellitus or diabetes mellitus only, but not in patients with ischemic stroke only compared to healthy controls. The expressions of platelet and plasma miR-495 and miR-107 showed no significant differences among these four groups. The expression of platelet miR-223 and miR-146a significantly correlated with plasma miR-223 and miR-146a levels, blood glucose concentration, and platelet activation rate.ConclusionsHyperglycemia may downregulate the expressions of miR-223 and miR-146a, leading to subsequent platelet activation in patients with diabetes mellitus. Low platelet and plasma miR-223 and miR-146a expression is a risk factor for ischemic stroke in Chinese diabetes mellitus patients.     

缺血性卒中患者血浆纤维蛋白原和颈动脉斑块关系的研究

目的 探讨血浆纤维蛋白原水平和颈动脉粥样硬化斑块的关系。方法 通过颈动脉超声检查，将81例缺血性卒中患者分成颈动脉有斑块组和无斑块组，检查两组患者的血浆纤维蛋白原水平和血清总胆固醇，低密度脂蛋白及其他动脉粥样硬化的危险因素。结果 颈动脉有斑块组纤维蛋白原、总胆固醇、低密度脂蛋白水平明显升高，颈动脉硬化的多因素分析表明，纤维蛋白原水平增高是颈动脉粥样斑块形成的危险因之一。结论 纤维蛋白原可能在动脉粥样斑块发生发展过程中起重要作用。     

Flow cytometry analysis of platelet P-selectin expression in whole blood--methodological considerations

P-selectin is an adhesion molecule found in the alpha granules of platelets. Activation occurs in response to a range of inflammatory and thrombotic agents resulting in rapid up-regulation. Flow cytometry methods have recently been described for the analysis of platelet P-selectin expression in whole blood. While introducing these methods into our laboratory it was noted that expression could be stimulated, in vitro, in a number of ways. This study shows that red cell lysis, the anticoagulant K3 EDTA and the time elapse between blood collection and antibody labelling had statistically significant effects on P-selectin expression. Post-labelling fixation, with CellFIX, caused no significant effect. We conclude that blood for P-selectin analysis should be collected in sodium citrate and that red cell lysis and centrifugation should be avoided. When comparing samples, the time between collection and labelling should be standardized. The relatively high CV for the assay indicates that all samples should be labelled and analysed in duplicate with the mean level reported.     

血清胆红素和P选择素在老年脑梗死患者中的动态变化及意义

目的探讨急性老年脑梗死患者血清P选择素和胆红素在不同时间、不同病情的动态变化及其临床意义。方法选择脑梗死患者98例(脑梗死组),据据神经功能缺损程度分为轻型38例、中型35例、重型25例,另选取健康体检者30例为对照组,测定脑梗死组患者发病1、3、7、14d和对照组血清可溶性P选择素和胆红素及高敏C反应蛋白水平的动态变化。结果脑梗死组1、3、7dP选择素、高敏C反应蛋白、总胆红素和间接胆红素明显高于对照组,差异有统计学意义(P<0.05)。与脑梗死轻型患者比较,中型和重型患者1、3、7dP选择素显著升高[(78.2±15.0)ng/L,(107.1±24.3)ng/L,(91.5±21.1)ng/L和(85.5±18.5)ng/L,(135.2±34.0)ng/L,(99.3±27.0)ng/L vs(48.8±6.7)ng/L,(86.0±10.9)ng/L,(72.5±11.3)ng/L,P<0.05]。结论 P选择素和胆红素可能参与脑梗死的病理过程,测定P选择素和胆红素有利于脑梗死的早期诊治及判断预后。     

Incidence and characteristics of spontaneous platelet macro-aggregation in acute ischemic stroke

Spontaneous platelet aggregation is a trigger for additional development of larger thrombi. Micro-aggregation is observed in 10% of diabetes approximately and blocked by P2Y12 inhibitors, whereas macro-aggregation is associated with overexpression of platelet α₂-adrenoreceptors and is not blocked by conventional anti-platelet medicines. We examined the incidence of spontaneous platelet macro-aggregation (SPMA) in acute ischemic stroke and analyzed its clinical characteristics. Out of 665 consecutive acute ischemic strokes, SPMA was found in 10 patients (1.5%, one tenth of micro-aggregation) despite no detection in 588 control subjects. Types of ischemic stroke were 4 atherothrombotic, 4 cardioembolic, and 2 lacunar strokes. Stroke with SPMA exhibited higher (worse) values of modified Rankin Scales (mRS) at discharge (3.00?±?0.53 vs 1.93?±?0.07, p?=?0.042 by Wilcoxon) compared with stroke without SPMA despite no difference at admission. The proportion of patients who were functionally independent (score 0–2 on the mRS) at discharge was lower in stroke with SPMA compared with stroke without SPMA (p?<?0.05 by chi-square test; OR 3.60, 95% CI 1.08–12.03; RR 2.04, 95% CI 1.05–2.86). It was intriguing that severe (high magnitude) SPMA was observed in 4 atherothrombotic stroke. Although anti-platelet therapy underwent, the proportion of atherothrombotic patients who were functionally improved and independent at discharge was lower in the presence of SPMA compared with the absence of SPMA (p?<?0.05 by chi-square test). The patients with SPMA were more likely to be older, having major disabilities, being less functionally improved during hospitalization, and being less functionally independent at discharge.

     

Increased tissue transglutaminase expression in human atherosclerotic coronary arteries

BACKGROUND AND OBJECTIVE: Transglutaminase 2 (TGase 2) is a calcium-dependent cross-linking enzyme that catalyzes a covalent iso-peptide bond between two proteins. Interestingly, this catalysis can activate the nuclear factor-kappaB (NF-kappaB) through the polymerization of the inhibitory protein of NF-kappaB (I-kappaB). The objective of the present study was to investigate the expression of TGase 2 in the human atherosclerotic human coronary artery, and the possible roles of TGase 2 in NF-kappaB activation. METHODS AND RESULTS: We explored whether expressions of TGase 2 and NF-kappaB are associated in atherosclerosis. Using human samples, we found that TGase 2 was markedly higher than normal in the neointimal tissue of atherosclerotic coronary arteries with atherosclerosis progression. TGase 2 activity was also increased approximately two-fold in the atherosclerotic vascular wall. In immunofluorescence analysis, NF-kappaB, COX-2, and TNF-alpha were co-localized at TGase 2-positive neointimal smooth muscle cells. A promoter assay test showed that NF-kappaB activity increased in both the human monocyte and human breast carcinoma cell by TGase 2, and that TGase 2-mediated NF-kappaB activation was reversed by TGase 2 siRNA. CONCLUSION: According to these results, we suggest that TGase 2 may function as an activator in the NF-kappaB pathway; this effect may occur in the atherosclerotic vessel wall.     

Measurement of platelet aggregation during antiplatelet therapy in ischemic stroke

Aspirin, ticlopidine and clopidogrel are used as a pharmacological means to efficiently decrease the number of reoccurrence of ischemic stroke (100-325 mg/d). This antiplatelet treatment could prevent the secondary stroke by approximately 22%. Laboratory effective platelet inhibition for the clinician, and methods for routine screening evaluation for the laboratory were studied. (1) For the standardisation of platelet aggregation technology blood samples of 150 healthy persons were studied in 5 centres. CARAT TX computerised optical aggregometer was used for measuring with collagen (2 microg/ml), epinephrine (10 microM), arachidonic acid 0.5 mM and ADP 5 microM as inductors. (2) Laboratory tests were compared in each centres performed in platelet-rich plasma of ischemic cardiovascular and stroke patients (n=823) taking 100-325 mg aspirin/d. (3) Blood samples of 555 ischemic stroke patients treated with aspirin (100-325 mg/d), 96 patients treated with ticlopidine (500 mg/d), and 67 patients treated with clopidogrel (75 mg/d) were evaluated, respectively.(1) The mean of maximal aggregation (%) - 2SD of untreated controls (n=150) were detected for collagen with 64%, epinephrine 59% and ADP 62%. (2) In 823 aspirin treated patients were found similar inhibition in different centres with same methods for standardisation. The mean inhibition level was in case of collagen 38%, epinephrine 37% and ADP 61%. (3) The distribution of ineffective platelet inhibition was detected in 17% of aspirin group (collagen and epinephrine), 4% of ticlopidine and 18% of clopidogrel group with ADP, respectively. Our findings were in the stroke cohort: effective inhibition levels: 36% in aspirin group, 73% in ticlopidine and 25% treated with clopidogrel. Platelet aggregation tests could help to find the optimal, and "custom taylored" dose of antiaggregating drugs in the secondary prevention of ischemic stroke.