特异性血小板抗体检测的实验研究

目的　建立一种简易、特异性强的血小板抗体检测方法。方法　利用磷酸氯喹溶液对血小板进行处理 ,去掉血小板相关抗原 (HLA抗原 ) ,用只含特异性抗原的血小板包被聚乙烯板来捕获血小板抗体。结果　与常用的SEPSA和淋巴细胞毒实验 (LCT)比较 ,该方法只表现血小板特异性抗体反应。结论　本方法能够鉴别血小板相关抗原的抗体和血小板特异性抗原的抗体 ,为临床血小板减少疾病的鉴别诊断、非溶血性发热反应和血小板输注无效的原因提供有用的参考依据     

Thrombosis triggered by severe arterial lesions is inhibited by oral administration of a glycoprotein IIb/IIIa antagonist

Platelet aggregation and thrombosis play an important role in the onset of acute coronary events. Regardless of the stimulus for activation, platelet thrombus formation is ultimately regulated through the IIb/IIIa receptor complex. The effects of oral administration of xemilofiban, a non-peptide mimetic of the RGDF sequence of the IIb/IIIa receptor complex, on thrombus formation were evaluated in a canine model. Xemilofiban significantly reduced platelet deposition on severely damaged arterial wall. Platelet deposition was reduced at both low (13 ± 1 from 56 ± 18 × 10⁶ platelets cm⁻²; P  < 0.05) and high (23 ± 2 from 111 ± 21 × 10⁶ platelets cm⁻²; P  < 0.01) shear rates. Platelet deposition was reduced to a monolayer as seen by electron microscopy (platelet–vessel wall interaction). Therefore, the availability of an orally active IIb/IIIa antagonist for chronic use may have significant value in preventing thrombus formation in those clinical situations associated with severe arterial injury, such as atherosclerotic plaque disruption.     

The assembly of the factor X-activating complex on activated human platelets

Summary.  Platelet membranes provide procoagulant surfaces for the assembly and expression of the factor X-activating complex and promote the proteolytic activation and assembly of the prothrombinase complex resulting in normal hemostasis. Recent studies from our laboratory and others indicate that platelets possess specific, high-affinity, saturable, receptors for factors XI, XIa, IX, IXa, X, VIII, VIIIa, V, Va and Xa, prothrombin, and thrombin. Studies described in this review support the hypothesis that the factor X-activating complex on the platelet surface consists of three receptors (for the enzyme, factor IXa; the substrate, factor X; and the cofactor, factor VIIIa), the colocalization of which results in a 24 million-fold acceleration of the rate of factor X activation. Whether the procoagulant surface of platelets is defined exclusively by procoagulant phospholipids, or whether specific protein receptors exist for the coagulant factors and proteases, is currently unresolved. The interaction between coagulation proteins and platelets is critical to the maintenance of normal hemostasis and is pathogenetically important in human disease.     

适量饮酒对健康成年男性血浆TXB2,6-Keto-PGF2a及血小板聚集功能的影响

①目的　观察适量饮酒对健康成年男性的血小板聚集功能及血浆血栓素B2 (TXB2 ) ,6 酮 前列腺素F2a(6 Keto PGF2a)的影响。②方法　将 80例健康成年男性随机分成 4组 ,分别空腹饮用矿泉水、啤酒、干红葡萄酒各 2 0 0mL ,白酒 50mL加矿泉水至 2 0 0mL .于饮前及饮后 2h分别测定血小板的聚集率及解聚率 ,并采血测定血浆TXB2 ,6 Keto PGF2a.③结果　矿泉水组饮后上述指标无变化 (t=0 .0 3～ 0 .84,P >0 .0 5) ;白酒、啤酒、红葡萄酒组饮后血小板聚集率减低 (t=8.1 2～ 2 4 .39,P <0 .0 1 ) ,解聚率升高 (t=2 8.48～ 35 .2 2 ,P <0 .0 1 ) ,血浆TXB2 降低 (t=2 5 .69～ 89.83 ,P <0 .0 1 ) ,而血浆 6 Keto PGF2a升高 (t=2 1 .0 6～ 2 3 .2 9,P <0 .0 1 )。④结论　健康成年男性适量饮酒可减低其血小板聚集功能 ,降低其血浆TXB2 ,提高其血浆 6 Keto PGF2a水平     

Influence of a calcium dependent protease inhibitor on platelet activation and secretion

Continuous proteolysis resulting in consumption of major cytoskeletal proteins may be essential for platelet activation and aggregation. In this study we evaluated the effect of a known protease inhibitor, Leupeptin, on agonist induced platelet aggregation and secretion. Platelets exposed to 10 ugs/ml of Leupeptin did not aggregate in response to the action of thrombin (0.2u/ml). However, a concentration of Leupeptin as high as 250 ugs/ml did not prevent arachidonate induced aggregation and secretion. Leupeptin (100 ugs/ml) effectively blocked thrombin (0.2 u/ml) induced elevation of cytosolic calcium, but did not affect arachidonate induced elevation of platelet intracellular calcium levels. At a concentration of 100 ug/ml, Leupeptin effectively blocked thrombin (0.5u/ml) induced clot formation of platelet poor plasma, suggesting that it can exert its effect on thrombin by preventing fibrinogen degradation. Effective K_i for the competitive inhibition of thrombin induced hydrolysis of a chromogenic substrate, S2238, by Leupeptin was 2.4 uM. Leupeptin inhibition of platelet function was reversible by washing platelets free of the polypeptide. Results of our study demonstrate that Leupeptin inhibits thrombin induced platelet activation, probably by interfering with its proteolytic activity on the platelet surface membrane. However, inhibition of platelet surface membrane associated proteases did not prevent activation of platelets by other agonists.     

检测各型乙肝患者血小板功能的临床意义

检测198例各型乙肝患者血小板功能的五个项目：血小板总数、粘附试验、聚集试验、血块退缩、血小板第3因子有效性，发现各期乙肝患者血小板功能的异常有显著性差异（P＜0．01）．并提示乙肝患者除有血小板数量的改变外，还有质量的改变，因此，全面的血小板功能检测可作为估计乙肝患者肝损害程度的辅助指标．     

Genetic typing of human platelet antigen 1 (HPA-1) by oligonucleotide ligation assay in a specific and reliable semi-automated system

Genotyping of platelet alloantigens with the possibility of using any type of cellular material as a source of DNA has become a preferred procedure, particularly in thrombocytopenic patients when platelet counts are too low for phenotyping. Recently human platelet antigen 1 (HPA-1) has been identified as an inherited risk factor for coronary thrombosis. The different detection methods currently used have disadvantages for large-scale DNA diagnosis, including the need for electrophoresis (allele-specific restriction enzyme analysis, amplification with sequence-specific primers) or the potential risk of reduced specificity (allele-specific oligonucleotide hybridization). In this report we describe the adaptation of an automated oligonucleotide ligation assay to genotype HPA-1 in polymerase chain reaction (PCR)-amplified DNA samples. HPA-1a and HPA-1b phenotypes corresponded to the results of the different genotyping assays. The genotypes determined with the ELISA-based PCR-oligonucleotide ligation assay were in 100% concordance with the results obtained by conventional allele-specific restriction enzyme site analysis and PCR amplification with sequence-specific primers. The automated oligonucleotide ligation assay provides a rapid, reliable, nonisotopic method to genotype human platelet antigens that can rapidly be applied to large population screening.     

Effect of dipyridamole with or without aspirin on urine protein excretion in patients with membranous glomerulonephritis

Summary The antiproteinuric effect of the antiplatelet agent dipyridamole has been assessed after inhibiton of thromboxane B₂ (TxB₂) synthesis in 8 patients with confirmed membranous glomerulonephritis. There were three study periods, each of 30 days, and 45 days apart, namely a washout period, treatment with dipyridamole 300 mg/d, and dipyridamole 225 mg/d plus aspirin 150 mg/d. On Days 1 and 30 of each study period serum and urine creatinine, 24-h excretion of protein, creatinine clearance, platelet aggregometry on whole blood and serum TxB₂ were measured. Treatment with dipyridamole alone or with aspirin produced significant inhibition of platelet aggregation and a fall in 24-h protein excretion; the latter amounted to 54% with dipyridamole alone and 56 % with dipyridamole plus aspirin (NS). Dipyridamole plus aspirin caused an 82 % reduction in serum TxB₂.