家兔血小板内钙离子的测定

ADP、花生四烯酸、凝血酶、血栓素A_2(T×A_2)及Ca~(2+)等对血小板的聚集功能都有影响。Ca~(2+)是血小板的成分之一,血小板内Ca~(2+)含量的增减必然会影响血小板的功能,所以,测定血小板内Ca~(2+)含量也越来越被重视。国内尚未见此类报道。我们测定了家兔血小板内Ca~(2+)的含量,以供国内广大研究者参考。     

刺激型抗人血小板McAb对人血小板细胞骨架蛋白的影响

本实验观察到HIP_2、APT_4和HI1173种刺激型McAb均能使PRP中血小板细胞骨架蛋白的主要成分肌动蛋白(actin)含量增加,而钙调蛋白抑制剂(EBB)则能显著抑制HIP_2和APT_4引起的肌动蛋白增加,抑制率分别为76.3％和48.95％,但不抑制HI117引起的肌动蛋白增加。此外,EBB能完全抑制APT_4引起的血小板聚集,部分抑制HIP_2引起的血小板聚集,不抑制HI117引起的血小板聚集。将3种刺激型McAb加入经0.3mmol/L EDTA溶液洗涤过3次的血小板悬液中,无透光度改变,也没有肌动蛋白动员,提示此3种McAb引起的血小板聚集及肌动蛋白动员除与Ca~(2+)有关外,还与血浆中某种(些)因子有关,Ca~(2+)—钙调蛋白系统在HIP_2,APT_4引起的血小板聚集及肌动蛋白动员中起着重要的作用。     

血小板活化时胞浆内Ca~(2+)的变化及抗钙药的影响

众所周知,血小板在血栓形成中起重要作用,而钙离子(calciumion,Ca~(2+))在发挥血小板功能中起了主导作用。对血小板功能和Ca~(2+)的关系的研究虽然很多,但由于血小板不同于其它分泌细胞,接触异物时容易形成血栓,给研究工作带来一定困难。本文介绍Ca~(2+)在血小板活化中所起作用及抗钙药的影响。     

血浆中分子物质对人红细胞膜Ca~(2+)-ATP酶活力的影响

本文初步观察了正常人中分子物质(N-MMS)和烧伤病人中分子物质(B-MMS)对正常人红细胞膜Ca~(2+)-ATP酶活力的影响。结果表明,不同保温时间N-MMS对红细胞膜Ca~(2+)-ATP酶活力有明显影响,保温时间越长酶活力抑制越显著(p<0.01),对照组变化不明显;不同浓度N-MMS和B-MMS对红细胞膜Ca~(2+)-ATP酶活力均有影响,浓度越高酶活力抑制越明显(P<0.01)。MMS对质膜Ca~(2+)-ATP酶的抑制作用可能是MMS导致细胞病理变化的一个重要环节。     

Aβ诱导PC-12细胞凋亡建立阿尔茨海默病细胞模型

目的:用β-淀粉样蛋白(Aβ_(25-35))诱导PC-12细胞凋亡以建立阿尔茨海默病细胞模型。方法:体外培养大鼠嗜铬细胞瘤PC-12细胞,以不同浓度Aβ_(25-35)诱导并于不同时间收获细胞,应用MTT法观察细胞活力,Fura-2/AM荧光分析法检测细胞内游离Ca~(2+)浓度,Hoech-st33258及碘化丙啶复染分析细胞凋亡。结果:Aβ_(25-35)作用于PC-12细胞后,细胞活力逐渐下降,并呈时间和剂量依赖性;同时细胞内Ca~(2+)浓度显著上升;不同浓度Aβ_(25-35)作用后,PC-12细胞于不同时间出现凋亡的典型形态学特征,该时间比Ca~(2+)浓度上升约晚6-12 h。结论:Aβ_(25-35)诱导PC-12细胞活力下降、细胞内Ca~(2+)浓度上升及细胞凋亡,可作为较理想的阿尔茨海默病细胞模型。     

用荧光染料fura-2法测定心室肌细胞内游离钙离子浓度

用fura-2荧光染料测定了静息时的酶解分离心室肌细胞内游离Ca~(2+)浓度,40mMKCI和5mM咖啡因都能使心室肌细胞内游离Ca~(2+)浓度增加,但KCI增加游离Ca~(2+)浓度需要细胞外液中存在Ca~(2+),而咖啡因则否,提示KCl增加细胞内游离Ca~(2+)浓度可能是通过细胞外Ca~(2+)内流,咖啡因则使细胞内贮存Ca~(2+)释放。     

再灌液中Ca~(2+)浓度的变化对心肌缺血再灌注损伤的影响

在大鼠Langendorff灌流模型上观察灌流液含不同浓度Ca~(2+)对心肌缺血再灌注损伤的影响。结果表明:随再灌液中Ca~(2+)浓度的增加(分别为0、1.5、3.0、5.0mmol/L),以心肌组织谷胱甘肽过氧化物酶活力下降、脂质过氧化物(MDA)含量、Ca含量及乳酸脱氢酶(LDH)漏出量增加为指标的组织损伤进行性加重。     

镉对小鼠免疫功能和淋巴细胞钙稳态影响的探讨

本文采用体外试验的方法观察到 50μmol/L的CdCl_2对LACA小鼠脾T淋巴细胞功能抑制26.08％,125～500μmol/L剂量下,对T淋巴细胞转化的抑制呈剂量—反应相关。500μmol/L时,抑制率达100％。50μmol/L CdCl_2可引起T淋巴细胞胞内游离Ca~(2+)浓度显著增高,温育40分钟时,增加80％(P<0.001),60分钟时增加115％,由于此测定是在无Ca~(2+)体系中进行的,所以Ca~(2+)浓度的增高可能是由细胞内钙库释放所致。同时还观察到CdCl_2对T细胞Ca~(2+),Mg~(2+)-ATPase活性抑制和细胞膜脂流动性下降,但其所需CdCl_2剂量水平较高。     

各种人参皂甙对人血小板5—羟色胺释放和凝聚的作用

本文作者利用人的富含血小板血浆观察了红参(Panax ginseng C.A.Meyer)根部分离的6种人参皂甙Rb 1,Rb_2,Rc,Rd,Re和~(Rg)1,特别是人参皂甙~(Rg)1,对由肾上腺索和凝血酶所引起的血小板凝聚和5-羟色胺释放的作用。同时研究了对细胞内游离Ca~(2+)的转运,花生四烯酸(AA)释放和甘油二酯生成的影响,以阐明其作用机制。在纤维蛋白原的存在(终浓度为0.3mg/ml)下,10μmol/L肾上腺素可导致血小板凝     

Duchenne型肌营养不良红细胞膜糖、脂质及Ca~(2+)-Mg~(2+)ATP酶的变化

对10例Duchenne型肌营养不良(DMD)患者红细胞膜进行了膜糖、脂质及Ca~(2+)-Mg~(2+)ATP酶活力的研究。结果为DMD红细胞膜唾液酸显著减少,而中性糖含量无变化;膜磷脂含量无明显改变,但膜胆固醇显著增加,磷脂/胆固醇之比显著降低,膜Ca~(2+)-Mg~(2+)ATP酶活力显著升高。表明DMD红细胞膜有组成和功能上的改变。     

血小板胞浆钙离子与脑梗塞

为研究血小板活化程度与脑梗塞临床严重程度之间的关系,选择２６例健康对照者和３０例脑梗塞患者,以Ｍａｔｈｅｗ、Ｔｏｒｏｎｔｏ和Ｂａｒｔｈｅｌ计分代表临床严重程度,水母发光蛋白导入－凝胶过滤法测量血小板胞浆钙离子浓度。结果表明,脑梗塞组血小板胞浆钙离子浓度明显高于对照组,脑梗塞组是（２．８７±０．３５）μｍｏｌ／Ｌ,对照组是（２．０１±０．３１）μｍｏｌ／Ｌ,两组间有极显著差异（Ｐ＜０．００１）。血小板胞浆钙离子与３种临床计分之间均无明显相关性。脑梗塞组血小板胞浆钙离子明显升高,显示脑梗塞患者急性期血小板处于易激活状态。血小板胞浆钙离子与３种临床计分无明显相关,表明血小板活化指标不能预示临床严重程度。     

激光扫描共聚焦显微镜观察血小板内钙离子浓度的变化

观察血小板内钙离子浓度的变化及细胞外钙离子对其影响，为探讨血小板内Ｃａ＋＋与疾病的关系及阐明药物作用机制提供理论依据。方法用不同浓度的二磷酸腺苷（ＡＤＰ）、５－羟色胺（５－ＨＴ）、花生四烯酸、瑞斯托霉素、胶原、凝血酶诱导血小板，通过激光扫描共聚焦显微镜观察标记了Ｆｌｕｏ－３的单个血小板内钙离子变化，以及细胞外钙离子对其影响。结果（１）除凝血酶外，其余诱导剂均可引起血小板钙离子浓度变化，且随着诱导剂浓度增加，钙波动频率增加，持续时间延长；（２）ＡＤＰ引起的血小板钙波动，在细胞外无钙离子时，只是幅度减少，而无频率变化；（３）５－ＨＴ引起的钙波动，在细胞外无钙时，波动消失。结论（１）ＡＤＰ、５－ＨＴ、花生四烯酸、瑞斯托霉素、胶原可引起血小板产生钙浓度变化。（２）不同诱导剂诱发的钙波动，其钙离子来源不同。     

重症急性胆管炎血小板的活化

动态观察２５例重症急性胆管炎（ＡＣＳＴ）手术前后２周内血小板内游离钙浓度、血小板聚集率、血小板数量等变化。结果显示，血小板在ＡＣＳＴ发病过程中明显活化，血小板细胞内钙离子浓度升高（２３０．５７±４８．３７ｎｍｏｌ／Ｌ），血小板聚集功能下降（１２．８０±３．０４％），血小板数量减少［（２４±５１）×１０９／Ｌ］，且与病情程度和胆道梗阻程度成正比。病情转归后，上述变化恢复正常。血小板活化持续不恢复静息状态，提示病情更严重和预后不良。     

Effects of platelet growth factors on human mesenchymal stem cells and human endothelial cells in vitro

The aim of the present in vitro study has been to investigate the effects of a enriched platelet derived growth factors on proliferation and migration of human endothelial and mesenchymal stem cells and on osteogenic differentiation of stem cells. Platelet rich plasma has been produced, yielding a four time higher number of thrombocytes than normal plasma. Degranulation of platelets has been performed by means of calcium and thrombin. Plasma has served as a control, whereas plasma in combination with calcium and thrombin was used to distinguish the difference between calcium and/or thrombin mediated effects and growth factor induced effects on the cells. The observed enhanced proliferation and migration of endothelial cells towards the platelet derived growth factors was driven by the plasma component of these preparations. However PDGF solely stimulated the migration and proliferation of mesenchymal stem cells. The increased osteogenic differentiation of growth factor treated mesenchymal stem cells was mostly driven by the high level of calcium used for the platelets degranulation. In summery, the different components of platelet derived growth factors work together to influence human endothelial and mesenchymal stem cells. This is of special clinically interest regarding the stimulation of bone healing in orthopaedic and traumatic surgery.     

剪切应力在血小板聚集及血栓形成中的作用

[目的 ]通过观察剪切应力诱导下血小板细胞骨架的变化 ,探讨力学作用对血栓形成的影响 .[方法 ]用锥板式流变血小板聚集仪给予剪切应力 ,以十二烷基硫酸钠 聚丙烯酰胺凝胶电泳法观察血小板内细胞骨架的变化 .[结果 ]在剪切应力的作用下 ,血小板内球状肌动蛋白转变为纤维状肌动蛋白 ,并与血小板聚集存在着平行的关系 ,而当合用钙调蛋白抑制剂时 ,纤维状肌动蛋白增多及血小板聚集同时受到抑制 .[结论 ]剪切应力的诱导和细胞内游离钙水平与血小板聚集及肌动蛋白含量变化有密切的关系 .     

血小板的软X射线谱学显微成像研究

探索性地应用软 X 射线谱学显微技术研究血小板的结构及钙元素成像的变化,采用谱学显微术对制取的 SD 大鼠血小板形态扫描透射成像并对血小板作钙元素双能对比衬度成像。血小板成像可看到血小板大小不等,有的伸出伪足;钙元素分布成像血小板在静息状态时胞内钙元素主要分布于质膜侧凹陷的钙池,诱导聚集后则扩散分布于胞质。软X 射线谱学显微成像能反应血小板钙元素分布,为钙的探测提供一种新方法。     

Platelet immune complex interaction in pathogenesis of Kawasaki disease and childhood polyarteritis

The role of platelets in the pathogenesis of vasculitis and the formation of coronary artery aneurysms was studied in 19 children with Kawasaki disease and five with polyarteritis. All patients with Kawasaki disease developed thrombocytosis in the third week of illness. The peak platelet count was significantly correlated (p less than 0.005) with the subsequent development of coronary artery aneurysms. The rise in platelet count was associated with the appearance in the circulation of a factor that induced aggregation and serotonin release in normal platelets. This factor was shown to be of high molecular weight, and its activity was lost at low pH--features suggestive of an immune complex. Immune complexes, detected by precipitation with polyethylene glycol, also appeared in the circulation as the platelet count increased. These complexes induced platelet aggregation, and there was a significant correlation (p less than 0.001) between the concentrations of IgG and IgA in the polyethylene glycol precipitated material and the platelet aggregating activity. Similar platelet aggregating activity was also detected in patients with polyarteritis but followed a different time course, persisting in the circulation for several months in association with continued disease activity. These findings imply that different mechanisms have a role in distinct phases of Kawasaki disease. The initial feverish phase (probably infective) is probably followed by an immune complex vasculitis that occurs when antibodies to the initiating agent appear in the circulation. The immune complexes aggregate platelets and induce release of serotonin. Platelet derived vasoactive mediators may increase vascular permeability and facilitate further deposition of complexes in the tissues.     

Activity of platelet in patients with high level of LDL and the effect of LDL on platelet glycoproteins

OBJECTIVE: To investigate the activity of platelet in patients with high level of low density lipoproteins (LDL) and the effect of LDL on platelet glycoproteins (GP). METHODS: Platelet glycoproteins, whose platelet were activated or unactivated, were measured by flow cytometry. RESULTS: The amount of the platelet membrane GP II b/III a in patients was not significantly different from that of the control when platelet was unactivated (P > 0.05); when platelet was activated by adenosine diphosphate (ADP), the amount of patients' platelet GP II b/III a was increased markedly in comparison with that in the control (P < 0.01). Having been preincubated with LDL, the platelets were activated by ADP and the amounts of GP II b/III a of patients group and the control were all increased obviously as compared with those in the platelets which were not incubated with LDL (P < 0.01; P < 0.01). There was no significant difference of the amount of granule membrane protein-140 (GMP-140) between patients and the control when platelet was activated by thrombin (P > 0.05). Having been preincubated with LDL, platelet was activated by thrombin, the amounts of GMP-140 on patients' and control platelet were all increased markedly (P < 0.01, P < 0.01). CONCLUSION: The activity of platelet in patients with high level of LDL is increased significantly. LDL can increase the expression of platelet glycoproteins.     

PLATELET FREE CALCIUM AND SERUM FREE CALCIUM IN ESSENTIAL HYPERTENSION

Intracellular free calcium of platelets and serum free calcium were studied in human essential hypertension. Intracellular free calcium of platelets was significantly higher in hypertensive patients than that in normotensive subjects, and this was correlated with blood pressure. There was no difference of serum free calcium between hypertensives and normotensive controls. Antihypertensive treatment with nifedipine resulted in a reduction of platelet free calcium, and this was correlated with the fall of blood pressure. In patients treated with clonidine, although there was no difference of platelet free calcium between hypertensives and normotensive controls, serum free clacium was significantly reduced. These results indicated that intracellular free calcium may be regulated by same hormonal or pharmacological factors which determined the height of blood pressure, calcium channel blockers may be more effective in prevention of cardiovascular and cerebrovascular complications caused by platelet hyperfunction in essential hypertension.