Arachidonic acid-stimulated platelet tests: Identification of patients less sensitive to aspirin treatment

Serum thromboxane-B2 (TxB2), together with arachidonic acid (AA)-induced platelet aggregation, are, at the moment, the most used tests to identify patients displaying high on-aspirin treatment platelet reactivity (HAPR). Both tests are specific for aspirin action on cyclooxygenase-1. While the correlation between serum TxB2 assay and clinical outcome is established, data are conflicting with regard to aspirin treatment and a possible association with AA-stimulated platelet markers and clinical outcome. To understand such discrepancy, we performed a retrospective study to compare both assays. We collected data from 132 patients receiving a daily dose of aspirin (100?mg/day) and data from 48 patients receiving aspirin on alternate days. All Patients who received a daily dose of aspirin were studied for AA-induced platelet aggregation together with serum TxB2 levels and AA-induced TxB2 formation was also studied in 71 patients out of entire population. Consistent with recommendations in the literature, we defined HAPR by setting a cut-off point at 3.1?ng/ml for serum levels of thromboxane B2 and 20% for AA-induced platelet aggregation. According to this cut-off point, we divided our overall population into two groups: (1) TxB2?<?3.1?ng/ml and (2) TxB2?>?3.1?ng/ml. We found low agreement between such tests to identify patients displaying HAPR. Our results show that AA-induced platelet aggregation >20% identify a smaller number of HAPR patients in comparison with TxB2. A good correlation between serum TxB2 and arachidonic acid-induced TxB2 production was found (r?=?0.76619).     

Effect of Coenzyme Q10 and green tea on plasma and liver lipids, platelet aggregation, TBARS production and erythrocyte Na leak in simvastatin treated hypercholesterolmic rats

This study was conducted to investigate the hypocholesterolemic effect of simvastatin (30 mg/kg BW) and antioxidant effect of coenzyme Q10 (CoQ10, 15 mg/kg BW) or green tea (5%) on erythrocyte Na leak, platelet aggregation and TBARS production in hypercholesterolemic rats treated with statin. Food efficiency ratio (FER, ADG/ADFI) was decreased in statin group and increased in green tea group, and the difference between these two groups was significant (p<0.05). Plasma total cholesterol was somewhat increased in all groups with statin compared with control. Plasma triglyceride was decreased in statin group and increased in groups of CoQ10 and green tea, and the difference between groups of statin and green tea was significant (p<0.05). Liver total cholesterol was not different between the control and statin group, but was significantly decreased in the group with green tea compared with other groups (p<0.05). Liver triglyceride was decreased in groups of statin and green tea compared with the control, and the difference between groups of the control and green tea was significant (p<0.05). Platelet aggregation of both the initial slope and the maximum was not significantly different, but the group with green tea tended to be higher in initial slope and lower in the maximum. Intracellular Na of group with green tea was significantly higher than the control or statin group (p<0.05). Na leak in intact cells was significantly decreased in the statin group compared with the control (p<0.05). Na leak in AAPH treated cells was also significantly reduced in the statin group compared with groups of the control and CoQ10 (p<0.05). TBARS production in platelet rich plasma was significantly decreased in the groups with CoQ10 and green tea compared with the control and statin groups (p<0.05). TBARS of liver was significantly decreased in the group with green tea compared with the statin group (p<0.05). In the present study, even a high dose of statin did not show a cholesterol lowering effect, therefore depletion of CoQ10 following statin treatment in rats is not clear. More clinical studies are needed for therapeutic use of CoQ10 as an antioxidant in prevention of degenerative diseases independent of statin therapy.     

急性冠状动脉综合征患者介入术前后血小板活化及血管内皮功能的变化

目的观察急性冠状动脉综合征患者介入治疗后血小板活化指标CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物及内皮功能的改变。方法60例急性冠状动脉综合征患者在冠状动脉介入术前和术后即刻以及次日采用流式细胞仪检测血小板活化指标CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物;双抗体夹心固相酶联免疫吸附试验测定血浆假血友病因子的表达水平;放射免疫测定法测定血浆内皮素1表达水平;酶法测定血浆一氧化氮的含量;彩色多谱勒超声诊断仪测量内皮依赖性血管舒张功能。选择健康体检者和稳定型心绞痛患者各30例作对照,观察急性冠状动脉综合征患者冠状动脉介入前后指标的变化并与对照组比较。结果与健康对照组和稳定型心绞痛组比,急性冠状动脉综合征组CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物明显增高(P<0.05或0.01);急性冠状动脉综合征患者介入术后即刻CD62p、CD63和糖蛋白Ⅱb/Ⅲa受体复合物与术前相比明显增高(P<0.01),但术后24h较术前无明显变化(P>0.05)。与健康对照组和稳定型心绞痛组比,急性冠状动脉综合征组假血友病因子、内皮素1的表达水平明显增高(P<0.01),内皮依赖性血管舒张功能和一氧化氮降低(P<0.05或<0.01);急性冠状动脉综合征患者介入术后即刻血浆假血友病因子和内皮素1水平升高(P<0.05或P<0.01),内皮依赖性血管舒张功能和一氧化氮水平降低(P<0.05),且介入术后24h假血友病因子水平也较术前升高(P<0.05),内皮依赖性血管舒张功能降低(P<0.05),但内皮素1和一氧化氮水平与术前差异无显著性(P>0.05)。结论血小板活化和内皮功能的损伤在急性冠状动脉综合征发生和发展过程中起重要的作用,冠状动脉介入术后血管内皮受到一定损伤,血小板有一定程度的激活。     

血小板活化因子在急性肝肾衰竭动物模型中对肾功能的影响

目的:了解血小板活化因子(PAF)在急性肝、肾衰竭动物模型中对肾功能的影响及可能的作用机制。方法:设4组大鼠,分别注射D-氨基半乳糖(D-GaLN)加内毒素(LPS),D-GaLN加PAF,D-GaLN加LPS加PAF受体拮抗剂及生理盐水,诱导急性肝、肾衰竭动物模型,测肝、肾功能指标并观察肝、肾组织病理改变。结果:注射D-GaLN大鼠的血清丙氨酸氨基转移酶、总胆红素比生理盐水组升高10倍以上,差异有显著性,病检有肝细胞坏死。注射PAF或LPS组与PAF受体拮抗剂组或生理盐水组比,肾功能指标差异有显著性。肾组织病检可见部分肾小管坏死。结论:PAF与急性肝、肾衰竭动物模型中的急性肾衰有关;PAF可能参与了内毒素相关的肝肾综合征(HRS)的形成;PAF受体拮抗剂对HRS可能有治疗作用。     

抗人血小板单克隆抗体SZ——47的功能研究

本文报道1株抑制型抗人血小板单克隆抗体 SZ—47。SZ—47能完全抑制 ADP 及肾上腺素诱导的血小板聚集;而对花生四烯酸,瑞斯托霉素诱导的血小板聚集无影响;对胶原诱导的血小板聚集无明显抑制作用。因此,推测单克隆抗体 SZ—47主要通过 ADP 途径来影响血小板的聚集功能。     

糖尿病患者微血管病变与血小板功能

测定21例有微血管病变和27倒无并发症的糖尿病人血小板功能，并与40例正常人作比较。结果发现糖尿病人，尤其是微血管病变者血浆血栓烷素（TXB2）、第八因子相关抗原（VWF）浓度及血小板膜糖蛋白（G、P）Ib显著高于对照组。提示血小板功能异常可能对糖尿病患者做血管并发症的发生起重要作用。     

99Tcm标记人源化抗人血小板膜糖蛋白Ⅲ a单克隆抗体SZ21F(ab)2血栓栓塞显像

目的用动物血栓栓塞模型显像评估99^Tc^m标记人源化抗人血小板膜糖蛋白（GP）Ⅲa单克隆抗体（简称单抗）F（ab）2片段SZ21F（ab）2的应用价值。方法通过体外抑制二磷酸腺苷（ADP）诱导的犬血小板聚集实验，评估SZ21F（ab）2与血小板结合的亲和性和特异性。以2-亚氨基噻吩盐酸盐（IT）法修饰SZ21F（ab）2分子的亚氨基，以99^Tc^m-葡庚糖酸钠（GH）转换络合法进行标记。分别用快速薄层层析（ITLC）法和ELISA测定标记物的放化纯及生物活性。对3条肺动脉血栓和8条（包括上述3条）后肢深静脉血栓栓塞比格犬模型进行显像研究。结果SZ21F（ab）2抑制ADP诱导的犬富含血小板血浆（PRP）聚集实验的半数有效剂量（IC50）为（2．49±1．88）μg／ml。ITLC法测得标记物的放化纯为90％～95％，ELISA测定结果表明标记后抗体保留了免疫活性。注射显像剂后1h，肺动脉血栓部位和后肢深静脉血栓部位均出现放射性浓聚。注射后3h，在体显像肺动脉血栓和后肢深静脉血栓栓塞模型的放射性靶／本底（T／B）比值分别为3．03±1．18和3．51±0.62。肺动脉血栓部位和后肢深静脉血栓部位的每克组织百分注射剂量率（％ID／g）分别为0．083％ID／g和0．076％ID／g。体外检测结果表明：肺动脉血栓与正常肺组织的单位质量放射性比值平均为12．8，后肢深静脉血栓与血液的单位质量放射性比值平均为5．2，与肌肉的比值平均为127.0。结论99^Tc^m-SZ21F（ab）2与人血小板具有较高的亲和力，有潜在的血栓显像应用前景。     

A multiparametric index of platelet in vitro aggregation in cerebrovascular disease

148 patients with various forms of cerebrovascular disease (CVD) were studied by means of a multiparametric analysis ofin vitro platelet aggregation, based on the following six parameters: ADP and epinephrine primary and secondary aggregation thresholds and percent maximum aggregation induced by optimal concentrations of ADP and epinephrine. These patients were assigned to four study groups, according to clinical diagnosis supported by CT scan, of transient ischemic attack and reversible neurological deficit (TIA-RIND), or completed stroke, in the presence or absence respectively of antiplatelet medical treatment at the time of the study. A statistically significant increase of thein vitro platelet aggregation was found in 44.4% of the untreated TIA-RIND patients and in 33.9% of the untreated stroke patients. However this last group showed a higher percentage of very marked hyperaggregation. Differences between the two treated study groups and controls were not signicant. No difference was found in collagen-and ristocetin-induced aggregation between the patient groups and the controls.

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Sommario 148 pazienti con varie forme di malattia cerebrovascolare, sono stati studiati con analisi multiparametriche dell'aggregazione piastrinica in vitro sulla base dei seguenti sei parametri: le soglie di aggregazione primaria e secondaria e l'aggregazione massima percentuale indotta da ADP ed Epinefrina. Questi pazienti sono stati suddivisi in 4 gruppi di studio in accordo con la diagnosi clinica confortata dai dati della TAC e cioè: TIA, RIND, o rammollimento in presenza o in assenza rispettivamente di un trattamento antiaggregante nel momento dello studio. è stato trovato un aumento statisticamente significativo dell'aggregazione in vitro delle piastrine nel 44.4% dei casi TIA, RIND non trattati e nel 33,9% dei casi di rammollimento non trattati. Quest'ultimo gruppo, però, ha dimostrato una più alta percentuale di iperaggregazione molto marcata. Le differenze tra i 2 gruppi di studio trattati con antiaggreganti e i controlli non erano significative. Inoltre nessuna differenza è stata riscontrata tra i gruppi e i controlli nell'aggregazione indotta da collageno e ristocetina.

     

Score Statistic to Test for Genetic Correlation for Proband-Family Design

In genetic epidemiological studies informative families are often oversampled to increase the power of a study. For a proband‐family design, where relatives of probands are sampled, we derive the score statistic to test for clustering of binary and quantitative traits within families due to genetic factors. The derived score statistic is robust to ascertainment scheme. We considered correlation due to unspecified genetic effects and/or due to sharing alleles identical by descent (IBD) at observed marker locations in a candidate region. A simulation study was carried out to study the distribution of the statistic under the null hypothesis in small data‐sets. To illustrate the score statistic, data from 33 families with type 2 diabetes mellitus (DM2) were analyzed. In addition to the binary outcome DM2 we also analyzed the quantitative outcome, body mass index (BMI). For both traits familial aggregation was highly significant. For DM2, also including IBD sharing at marker D3S3681 as a cause of correlation gave an even more significant result, which suggests the presence of a trait gene linked to this marker. We conclude that for the proband‐family design the score statistic is a powerful and robust tool for detecting clustering of outcomes.