高脂血症循环白细胞自发活化作用的研究

高血脂是心脑血管病的重要危险因素。活化白细胞在缺血过程中微血管嵌塞和组织损伤中起重要作用。为了研究血清胆固醇对循环白细胞活化作用的影响，采用硝基蓝四唑试验测量了高脂血症家兔循环白细胞自发活化率（ＳＡＲ）。结果指出，高脂血症动物循环白细胞ＳＡＲ（％）显著高于对照组（Ｐ〈０．０１）。ＳＡＲ升高与血清胆固醇水平有关。循环白细胞ＳＡＲ升高导致白细胞粘附分子ＣＤ１１／ＣＤ１８表达增加和循环障碍。因此循环白细     

血小板生成素及血小板生成素Ⅱ对人血小板活化的影响

目的:检测血小板生成素(TPO)及TPOⅡ在体外对人血小板活化的影响。方法:取正常健康成人富血小板血浆,分别与血小板生成素(rhTPO)、TPOⅡ及磷酸盐溶液孵化,通过荧光单克隆抗体标记血小板表面CD62P及CD41分子,用流式细胞术测定CD62P/CD41比率,观察各组血小板活化率。结果:rhTPO、TPOⅡ组血小板活化率与PBS组无明显差异,P＞0.05。结论:血小板生成素不会导致血小板异常活化,可应用于血小板生成减少的各种情况。     

高脂血症循环白细胞自发活化作用的研究

高血脂是心脑血管病的重要危险因素。活化白细胞在缺血过程中微血管嵌塞和组织损伤中起重要作用。为了研究血清胆固醇对循环白细胞活化作用的影响，采用硝基蓝四唑试验测量了高脂血症家兔循环白细胞自发活化率（SAR）。结果指出，高脂血症动物循环白细胞SAR（％）显著高于对照组（P＜0.01）。SAR升高与血清胆固醇水平有关。循环白细胞SAR升高导致白细胞粘附分子CD11／CD18表达增加和微循环障碍。因此循环白细胞SAR升高是心脑血管病重要危险因素之一。     

NO在脂联素抑制高脂血症大鼠血小板聚集中的作用

目的: 探讨一氧化氮(NO)信号转导通路在脂联素抑制高脂血症血小板聚集机制中的作用。方法: 采用成年大鼠饲以高脂饲料14周,分离其血小板并以重组脂联素(rAPN)孵育。采用免疫荧光、Western blotting等方法观察检测血小板聚集、NO含量、超氧化物含量、内皮型一氧化氮合酶(eNOS)/诱导型一氧化氮合酶(iNOS)的表达和抗氧化物活性。结果: 采用rAPN处理能抑制高脂血症诱导的血小板聚集(P<0.05),并导致血小板NO的生成显著减少。同时,在高脂血症血小板中,采用rAPN处理还能显著减少超氧化物的生成(降低62%, P<0.05) 并增强其抗氧化能力(增加38%, P<0.05)。此外,高脂血症诱导的eNOS磷酸化的降低和iNOS表达的增加在rAPN处理后被显著逆转(P<0.05, P<0.01)。结论: 脂联素是一种抑制高脂血症血小板聚集的脂肪细胞因子,其机制与减少超氧化物水平、增加抗氧化物活性和阻断iNOS的表达有关。     

高血压导致血小板活化的机制

高血压时,可引起血小板活化、聚集成为血小板血栓的影响因素包括内皮受损、内皮活性物质释放、内皮所生成的具有抗血小板聚集功能的NO减少,以及血小板自身的活化、血小板内源性NO生成减少等。它们相互交织、相互促进,共同导致血小板血栓的形成。在临床治疗中选择性地应用具有抗血小板聚集的抗高血压药物,有望改善血小板的易聚性。     

高脂血症大鼠海马超微结构

目的：观察高脂血症大鼠海马的超微结构变化。方法：将SD大鼠饲以高脂饲料,饲养6W后测血脂,应用透射电镜观察海马超微结构。结果：实验组血清总胆固醇(6．65mmol／L)及血清低密度脂蛋白胆固醇(4．41mmol／L)升高明显,差异显著。电镜下实验组大鼠海马锥体细胞超微结构出现一系列病理改变,其中尤以神经元内出现大量脂滴最为显著。结论：高脂血症可诱导大鼠海马内神经元出现一系列病理改变,为今后进一步探讨血脂代谢异常与中枢神经系统的神经退行性病变关系提供了形态学依据。     

血小板生成素对体外人血小板活化的影响

目的: 研究血小板生成素(TPO)及其他造血生长因子在体外对人血小板活化的影响。方法:应用荧光标记单克隆抗体和流式细胞技术。结果:终浓度120 ng/mL的TPO在体外能直接诱导人血小板活化,活化率为8.89%~39.92%,中位数17.43%,40 ng/mL的较低浓度TPO及100 ng/mL粒细胞-巨噬细胞集落刺激因子(GM-CSF)和白细胞介素-3(IL-3)对血小板活化无影响。结论:TPO对血小板功能有促进作用,较高浓度的TPO可直接诱导血小板活化。     

一氧化氮对家兔冠状动脉阻塞后血小板活化的影响

将３０只兔分为３组，Ｉ组行左冠状动脉前降支假扎，Ⅱ组及Ⅲ组行ＬＡＤ线线缝扎３０ｍｉｎ后再灌注４ｈ。Ⅲ组于ＬＡＤ结扎后静滴硝酸甘油，Ⅰ，Ⅱ组静滴生理盐水。３组均观察手术前后各时点血浆一氧化氮，血小板表面α颗粒膜蛋白，血栓素Ｂ２浓度。结果显示，Ⅰ组手术前后血浆ＮＯ，ＧＭＰ－１４０，ＴＸＢ２浓度无变化，Ⅱ，Ⅲ组在心肌缺血及再灌注后ＮＯ浓度降低，ＧＭＰ－１４０和ＴＸＢ２浓度升高，Ⅱ组上述变化更为显著。     

血小板活化因子对嗜酸性粒细胞的活化作用

用多粘菌素Ｂ注射，造成豚鼠腹腔渗出液中嗜酸性粒细胞（Ｅｏｓ）增多，分离出其中的Ｅｏｓ，测定血小板活化因子（ＰＡＦ）对Ｅｏｓ过氧化物酶（ＥＰＯ）活性、Ｅｏｓ沉淀密度和存活时间的作用。结果表明：ＰＡＦ能增强ＥＰＯ活性，诱导Ｅｏｓ脱颗粒，其最大作用浓度分别为１０＾－７ｍｏｌ／Ｌ和１０＾－６ｍｏｌ／Ｌ。淋巴细胞培养上清液能显著增强ＰＡＦ的脱颗粒作用。１０＾－６ｍｏｌ／Ｌ ＰＡＦ还能使１５．９％的正常密度Ｅ     

原发性血小板减少性紫癜患者血小板活化状态的检测和意义

原发性血小板减少性紫癜(idiopathic thrombocytopenicpurpura，ITP)是因免疫机制使血小板破坏增多而致的临床常见出血性疾病，又称免疫性血小板减少性紫癜。本文以血小板膜表面纤维蛋白原受体(FIB-R)、P-选择素(CD62P)的表达反映血小板的活化状态，分析比较血小板数量与血小板活化状态的关系，探讨血小板活化状态的改变在ITP病理生理机制中的意义。     

Morphological characterization of surface-induced platelet activation

Morphological changes of platelets activated on glass and dimethyldichlorosilane-treated glass were investigated using video microscopy. The platelet morphological changes were quantified by measuring the area and circularity of spreading platelets. In addition, re-organization of cytoskeletal structures of spread platelets was examined. The effects of precoated albumin and fibrinogen on the platelet spreading kinetics were examined as a function of surface protein concentrations. Results showed that platelet shape changes were very sensitive to the surface concentration of precoated proteins. In general, platelets on fibrinogen-precoated surfaces spread fully to a circular shape and developed an extensive inner filamentous zone. In the presence of albumin on the surface, however, platelets could not spread fully and the development of the inner filamentous zone was very poor. For both albumin and fibrinogen, the maximum effects of precoated proteins on platelet shape changes were observed when the surface protein concentration reached the monolayer concentration.     

Effects of marathon running on platelet activation markers : direct evidence for in vivo platelet activation

We used the ADVIA 2120 Hematology System (Bayer HealthCare, Diagnostics Division, Tarrytown, NY) to study the effects of vigorous exercise on CBC count, WBC differential, RBC fragmentation, and platelet activation parameters in 32 healthy participants in a 26.2-mile (42.2-km) marathon. The runners demonstrated increases in hematocrit and platelet count consistent with dehydration and leukocytosis indicative of demargination of neutrophils or inflammation secondary to tissue destruction (eg, rhabdomyolysis). The number of RBC fragments was increased after the race (P = .008), consistent with exercise-induced hemolysis. The mean platelet component, a measure of platelet granularity, was decreased (P < .0001), and the number of platelet clumps was increased (P = .0026), providing evidence for in vivo platelet activation during the marathon. By using direct measurement of platelet granularity, our study confirms the in vivo activation of platelets by vigorous exercise and establishes the usefulness of automated cell counters for the assessment of platelet activation and of RBC fragmentation in this setting.     

Glomerular localization of platelet cationic proteins after immune complex-induced platelet activation

Synthetic polycations bind to glomerular polyanions (GPA) and increase permeability to macromolecules and immune complexes. Platelet factor 4 and other platelet cationic proteins also bind to GPA and may play a role in immune complex deposition. Here we examine the potential of locally released cationic proteins to bind to GPA after immune complex-induced platelet activation within the renal microvasculature. Rabbits were immunized against bovine serum albumin (BSA), and BSA (2 or 4 mg/ml in buffered saline) was infused into the left renal artery to deliver 8 or 16 mg of BSA over 20 minutes. Thirty minutes later, kidneys were removed and tissue processed for light, immunofluorescence, and electron microscopy for the assessment of glomerular alterations and the localization of immune complexes (IgG and BSA), platelet factor 4, and platelet cationic proteins. GPA was measured by quantitative ultrastructural assessment of polyethyleneimine binding sites. Glomerular capillaries contained large intraluminal immune complexes and platelet aggregates. Also, numerous deposits were observed within subendothelial and subepithelial aspects of the glomerular basement membrane (GBM). Immunofluorescence and immunocytochemistry revealed prominent localization of platelet factor 4, platelet cationic proteins, IgG and BSA within peripheral capillary walls of glomeruli concomitant with a reduction in GPA. Glomeruli of controls or contralateral kidneys did not show GBM localization of immune complexes or platelet proteins. Thus, nascent formation of immune complexes in capillaries was associated with platelet activation and deposition of endogenous cationic proteins in the GBM. This mechanism may be involved in neutralization of GPA and mediation of increased permeability, which leads to GBM deposition of immune complexes.     

Evidence of platelet activation in multiple sclerosis

Objective  

A fatality in one multiple sclerosis (MS) patient due to acute idiopathic thrombocytopenic purpura (ITP) and a near fatality in another stimulated our interest in platelet function abnormalities in MS. Previously, we presented evidence of platelet activation in a small cohort of treatment-naive MS patients.     

Detection method for platelet activation markers

The assessment of platelet activation levels may be useful for identifying patients who would benefit from antiplatelet therapy and prediction of ischemic events. Laboratory markers of platelet activation include activation-dependent changes in glycoprotein (GP) IIb/IIIa complex, exposure of granule membrane proteins, binding of secreted platelet proteins, and development of procoagulant surfaces. Whole blood flow cytometry is a popular and useful method for the detection of these markers of platelet activation. Monoclonal antibodies against platelet surface glycoproteins are used to identify activated platelets.     

Platelet activating factor and endotoxin-induced platelet activation

Central Research Institute of Epidemiology, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. I. Pokrovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 107, No. 5, pp. 538–540, May, 1989.