Effects of vinblastine on malondialdehyde formation, serotonin release and aggregation in human platelets

Effects of the microtubular agent vinblastine on human platelet malondialdehyde formation, [14C]serotonin release and aggregation were studied in suspensions of [14C]serotonin-labelled platelets. Vinblastine caused dose-dependent inhibition of malondialdehyde formation and aggregation in platelet suspensions stimulated with thrombin, ADP or palmitaldehyde acetal phosphatidic acid (PGAP). Malondialdehyde formation, aggregation and [14C]serotonin release caused by threshold doses of thrombin were reduced but not abolished by 100 muM vinblastine; 30-100 muM vinblastine abolished ADP- and PGAP-induced malondialdehyde formation and [14C]serotonin released and transformed ADP- and PGAP-induced irreversible aggregation to a diminished reversible response. Arachidonate conversion to malondialdehyde catalysed by human platelet microsomes was inhibited by vinblastine and the cyclooxygenase inhibitors indomethacin and aspirin, but not by salicylate. Vinblastine inhibited the microsome-catalysed formation of malondialdehyde from prostaglandin H2. It is concluded that vinblastine inhibits the thromboxane pathway of arachidonate metabolism in stimulated platelets, consequently inhibiting release and aggregation, and that this effect of vinblastine may be, at least in part, independent of its antimicrotubular actions.     

盐酸曲美他嗪缓释片体外释放度研究

目的 以羟丙甲基纤维素为骨架材料制得盐酸曲美他嗪缓释片,并对释药机制进行探讨.方法 进行体外释放度试验,研究体外释放度测定方法,辅料和加速稳定性试验对释放度的影响.结果 制得的盐酸曲美他嗪缓释片具有明显的缓释作用,体外释放符合一级释药动力学规律.结论 制备盐酸曲美他嗪缓释片的方法简单,适于工业化生产.     

Inhibitory effect of tiaramide of aggregation in vivo and on electrophoresis of rabbit platelets

Effects of tiaramide, aspirin an indomethacin were studied on rabbit platelet aggregation in vivo and on platelet electrophoretic mobility. When tiaramide (6 mg/kg), aspirin (30 mg/kg) or indomethacin (1.3 mg/kg) was injected into the ear vein of rabbit during 60 sec, tiaramide only inhibited ADP-induced aggregation, 20 min after the injection. All three drugs prevented collagen-induced aggregation 20 and 120 min after the injection. Tiaramide and aspirin prevented aggregation 24 hours later. The inhibitory effects on the aggregation of tiaramide are presumably independent of prostaglandin synthesis, because malondialdehyde (a metabolite of PGG2) production was not influenced. Tiaramide reduced cyclic AMP levels in platelets after 20 min incubation, despite the ability of this agent to inhibit platelet aggregation. Tiaramide, aspirin and indomethacin per se has no effect on platelet electrophoretic mobility, while tiaramide prevented the decrease in the mobility produced by ADP. Tiaramide and aspirin also depressed the decrease in the mobility produced by collagen.     

普鲁卡因胺在体外对兔血小板聚集和血栓素B2生成的抑制作用

目的：研究普鲁卡因胺（ＰＡ）对凝血酶诱导血小板聚集和血栓素Ｂ２（ＴＸＢ２）产生的影响。方法：用比浊法和放射免疫分析法．结果：普鲁卡因胺８．５，３４，１３６和５４４μｍｏｌ·Ｌ＾－１有明显抑制作用。抑制率分别为４５％±３７％、１４８％±３２％，８８％±２３％，９２％±１５％和５３％±２４％，６５％±２６％，９０％±６％，９５％±６％。ＰＡ的浓度与血小板聚集和ＴＸＢ２产生的抑制效力之间，以及血小板聚集     

ONO-3708和S-145对STA_2介导的家兔血小板变形和聚集反应的抑制作用(英文)

目的:评价ONO-3708和S-145对血小板变形和聚集反应的不同抑制模式。方法:以透光度法测量血小板变形和聚集反应,荧光图像分析法测量单细胞内游离钙的变化。结果:(1)STA_2的聚集反应可被依他酸,ONO-3708和S-145抑制(P<0.01),血小板变形仅被S-145抑制。(2)S-145的抑制作用随孵育时间延长而增强,ONO-3708不变。(3)洗脱后ONO-3708的作用消失,而S-145抑制作用依然存在。(4)STA_2的细胞内游离钙动员部分被ONO-3708和依他酸取消(P<0.01),但可被S-145完全抑制。结论:S-145和ONO-3708分别作用于血小板TXA_2受体的不同结合位点。     

Effects of 5-HT released from platelets on thrombin-induced aggregation and ATP release in rabbit pla

Ｅｆｅｃｔｓｏｆ５ＨＴｒｅｌｅａｓｅｄｆｒｏｍｐｌａｔｅｌｅｔｓｏｎｔｈｒｏｍｂｉｎｉｎｄｕｃｅｄａｇｇｒｅｇａｔｉｏｎａｎｄＡＴＰｒｅｌｅａｓｅｉｎｒａｂｂｉｔｐｌａｔｅｌｅｔｓｉｎｖｉｔｒｏＬＩＢａｉＹａｎ１，ＬＩＷｅｎＨａｎ（Ｄｅｐａｒ...     

兔血小板释放的内源性5—HT对凝血酶诱导的血小板聚集和ATP释放的？…

AIM: To study the effects of arachidonic acid (AA)-induced endogenous serotonin (5-HT) release on platelet aggregation and ATP release by thrombin (Thr). METHODS: Platelet aggregation and release reaction were quantified by light transmission in platelet-rich-plasma (PRP) and the amount of ATP in medium. The effects of endogenous 5-HT were evaluated by the filtration of content in cuvette A (content A) containing endogenous 5-HT into cuvette B in which Thr-induced aggregation was observed in the absence/presence of ?(+/-)-5 (Z)-7-[3-endophenylsulfonylamino [2.2.1] bicyclohept-2-exo-yl]heptanoic acid, sodium salt? (S-145) or/and methysergide (Met). RESULTS: (1) AA 100 and 200 mumol.L-1 induced aggregation and ATP release in cuvette A. When the aggregation reached a peak, the content A directly caused platelet aggregation in cuvette B, and it was inhibited by S-145 100 nmol.L-1, Met 30 mumol.L-1, and inhibited more potently by S-145 + Met. (2) In the presence of S-145 100 nmol.L-1 in cuvette B, aggregations by Thr 0.1 and 0.3 IU.L-1 were enhanced (P < 0.01) by the filtrate, while Thr 0.5 IU.L-1-caused ATP release was suppressed (P < 0.01) without the effect on aggregation. Preincubation with S-145 and Met, the effects of the filtrate on aggregation and ATP release were abolished. (3) By prolongation of the time intervals between filtration and addition of Thr, the aggregation was enhanced and ATP release was reduced. CONCLUSION: Endogenous 5-HT was released from activated platelet and plays, in turn, a role in the regulation of platelet aggregation by the superimposition of cytosolic-free calcium ([Ca2+]i) and the feedback loop to regulate release reaction and calcium.     

Inhibitory effects of serotonin and sodium ascorbate on the oxidative aggregation of lipoproteins

Milk lipoproteins (MLPs) are structurally and biochemically similar to blood lipoproteins, which allow the former to be used as model objects for studying the properties of the latter. The results of turbidimetric measurements showed a change in the light scattering from MLP suspensions upon contact with Fe3+ ions in the free from or in chelate complexes with o-phenanthroline and EDTA. No such effect was observed for Fe2+ ions. The effect of Cu2+ ions (in microscopic amounts) was similar to that of Fe3+, while Ca2+ and Mg2+ produce no effect. It was found that 1,1-azabicyclohexanecarbonitrile-2-methylpropionamidine dihydrochloride (an azoinitiator capable of spontaneous decomposition with the formation of peroxide radicals in an oxygen containing-medium) introduced into an MLP suspension produces the same effect as Fe3+ and Cu2+ ions. Study of the particle size distribution in a microcapillary by the method of impedance measurements showed that a change in the light scattering from the suspension is caused by the MLP aggregation. The action of aggregation factors upon the MLPs led to their oxidation, as indicated by accumulation of the TBA-active products. The ability of copper ions to oxidize MLPs agrees with the data reported on the copper-ion-induced oxidation of blood lipoproteins, which was observed in studying a relationship between this oxidation and clinical manifestations of atherosclerosis. Thus, pronounced oxidation of both milk an blood lipoproteins in the presence of microscopic amounts of copper ions is indicative of a similarity of these processes. The process of lipoprotein aggregation induced by various oxidizing agents is inhibited by sodium ascorbate and serotonin. At the same time, beta-naphthol (an antioxidant soluble in lipids) does not affect the aggregation process. It is suggested that the oxidative aggregation of lipoproteins mag be related to the problem of atherogenesis and thrombogenesis.     

丹酚酸B镁盐对兔洗涤血小板聚集和5-HT释放反应的影响(英文)

AIM: To study the effects and mechanism of magnesium lithospermate B(MLB) on rabbit platelet aggregation and 5-HT release. METHODS: The platelet aggregation was determined by Born's method. Release of serotonin (5-HT) and formation of thromboxane A2 (TXA2) were measured by fluorophotometry and radioimmunoassay (RIA) respectively. Cytoplasmic free Ca2+ concentration ([Ca2+]i) in platelets was measured by Fura 2-AM fluorescence technique. RESULTS: In washed platelets, thrombin (200 U/L) or arachidonic acid (AA) (30 mumol/L)-induced aggregation was inhibited by MLB 50-800 mg/L in a concentration-dependent manner. In addition, MLB had more inhibitory effects on platelet aggregation in the absence of extracellular calcium with IC50 of 102 mg/L than in the presence of CaCl2 1 mmol/L with IC50 of 194 mg/L. MLB concentration-dependently decreased the thrombin-activated release of 5-HT, whereas it did not affect the formation of TXA2 in platelets. Furthermore, MLB not only inhibited the rise of [Ca2+]i in thrombin stimulated platelets, but decreased the [Ca2+]i in resting platelets. CONCLUSION: MLB inhibited the aggregation and 5-HT release in rabbit platelets and it is probably by attenuating intracellular calcium concentration.     

Dual effects of 5-hydroxytryptamine on stable analogue of thromboxane A~(2~_) induced aggregation and release reaction in rabbit platelets

目的：研究５ＨＴ对ＳＴＡ２血小板聚集和释放反应的影响及可能的分子机制．方法：以透光法，介质中ＡＴＰ含量及荧光图像法评价血小板变形，聚集反应和［Ｃａ２］ｉ水平．结果：（１）５ＨＴ预处理可消除ＳＴＡ２的血小板变形，ＳＴＡ２０３μｍｏｌ·Ｌ－１的聚集增强，ｌ－３μｍｏｌ·Ｌ－１的聚集不变，释放反应抑制．（２）５ＨＴ预处理增加ＳＴＡ２０３μｍｏｌ·Ｌ－１的［Ｃａ２＋］ｉ，降低３μｍｏｌ·Ｌ－１的［Ｃａ２＋］ｉ降低．（３）延长加入５ＨＴ和ＳＴＡ２的间隔，ＳＴＡ２０３μｍｏｌ·Ｌ－１的聚集增强，３μｍｏｌ·Ｌ－１的聚集不变，释放反应抑制．结论：５ＨＴ对ＳＴＡ２介导的聚集和释放反应有双重影响．对ＳＴＡ２［Ｃａ２＋］ｉ的调节可能是上述反应的分子机制．     

649例盐酸曲美他嗪缓释片临床应用合理性评价

目的:调查住院患者盐酸曲美他嗪缓释片的使用情况,为临床合理用药提供参考。方法:采用回顾性的研究方法,调取我院2018年1月1日–8月31日期间使用盐酸曲美他嗪缓释片的住院患者信息,收集患者性别、年龄、临床诊断、血清肌酐值、药物用法用量、疗程等数据,对上述指标进行统计分析。结果:使用盐酸曲美他嗪缓释片的患者共计649例,60岁以上占78.74%,主要疾病类型为冠心病;其中,评价为合理用药304例(46.84%),不合理用药345例(53.16%)。不合理用药问题主要涉及超适应证用药(197例,30.35%)、禁忌证用药(52例,8.01%)、给药时机不适宜(27例,4.16%)、用法用量不适宜(116例,17.87%)。结论:我院盐酸曲美他嗪缓释片在临床使用上不合理应用普遍存在,需加强管理,以促进其在临床使用合理、规范。     

5HT对STA2介导的血小板聚集和解释反应的双重影响

目的：研究５－ＨＴ对ＳＴＡ２血小板聚集和释放反应的影响及可能的分子机制。方法：以透光法，介质中ＡＴＰ含量及荧光图像法评介血小板变形，聚集反应和［Ｃａ＾］ｉ水平。结果：（１）５－ＨＴ预处理可消除ＳＴＡ２的血小板变形，ＳＴＡ２ ０．３μｍｏｌ·Ｌ＾－１的聚集增强，１－２ｍｏｌ·Ｌ＾－１的聚集不变，释放反应抑制。（２）５－ＴＨ预处理增加ＳＴＡ２ ０．３μｍｏｌ·Ｌ＾－１的［Ｃａ＾２＋］ｉ降低３μｍｏｌ·     

Formulation and evaluation of trimetazidine dihydrochloride extended release tablets by melt congealing method

Trimetazidine dihydrochloride, a cellular antiischemic agent indicated in the management and prophylaxis of angina pectoris is given as 20 mg thrice daily in the conventional dosage regimen. The purpose of the present study was to formulate and evaluate twice a day extended release tablets containing 30 mg trimetazidine dihydrochloride. The method developed to formulate these extended release tablets was melt congealing followed by wet granulation which exhibited uniform sustained release action and overcame the drawbacks of multidosing. The formulation was developed with Methocel^® K100M and stearic acid as release retardant.     

N-(4-胍基丁基)丁香酰胺对家兔血小板聚集性的影响

目的考察N-(4胍基丁基)丁香酰胺对家兔体外血小板聚集的影响。方法以盐酸益母草碱为阳性对照,以二磷酸腺苷(Adenosine Diphosphate,ADP),花生四烯酸(Arachidonic Acid,AA),胶原(Collagen,COL)为诱导剂诱导家兔体外血小板聚集,采用Born氏比浊法,利用血小板聚集仪测定5 min血小板最大聚集率,观察不同浓度的N-(4胍基丁基)丁香酰胺对家兔体外血小板聚集的影响。结果不同浓度N-(4胍基丁基)丁香酰胺对ADP、AA、COL诱导的家兔体外血小板聚集均有一定抑制作用。结论 N-(4胍基丁基)丁香酰胺具有一定的体外抗血小板聚集的作用。     

联合应用盐酸曲美他嗪治疗微血管心绞痛的临床观察

目的：观察联合应用盐酸曲美他嗪治疗微血管心绞痛的临床治疗效果,提供更可靠的药物选择。方法将2009年8月至2013年10月收治的62例微血管心绞痛患者随机分为治疗组（32例）和对照组（30例）。治疗组患者给予盐酸曲美他嗪20 mg（每天口服3次）、单硝酸异山梨酯60 mg（每天口服1次）;对照组患者仅给予单硝酸异山梨酯60 mg（每天口服1次）。观察两组患者治疗2、4周后心绞痛缓解情况。结果治疗组治疗2、4周后有效率[62.5％（20/32）、87.5％（28/32）]明显高于对照组[36.7％（11/30）、53.3％（16/30）],差异均有统计学意义（P＜0.05）;治疗组治疗4周后有效率高于治疗2周后,差异有统计学意义（P＜0.05）。结论联合应用盐酸曲美他嗪治疗微血管心绞痛不良反应少、耐受好,且应用时间越久,疗效越显著。     

Inhibitory effect of cepharanthine on collagen-induced activation in rabbit platelets

Cepharanthine incorporated into rabbit platelets dose dependently, inhibited calcium influx as well as aggregation in response to collagen, and also inhibited arachidonate release in response to collagen and A23187 in the same concentration ranges. The latter action of cepharanthine was shown not to be due to the direct action on phospholipase A2 molecules but to the depression of susceptibility of substrate phospholipids to enzymatic hydrolysis. These depressed functions, as well as the inhibited aggregation, were almost restored by removing the bound drugs from the platelets. Arachidonate-induced aggregation and prostaglandin synthesis from externally added arachidonate were not suppressed by the addition of cepharanthine. These results suggest that cepharanthine physically changes the lipid properties and thereby inhibits the function of the calcium channel or the susceptibility of substrate phospholipids to enzymatic hydrolysis by phospholipase A2.     

MN-9202对兔血小板聚集、5-HT释放、TXB_2合成及Ca~(2 )转运的影响(英文)

目的:研究新二氢吡啶类钙拮抗剂MN-9202对兔血小板激活的影响,并探讨其作用机制。方法:以Fu-ra-2 AM为荧光探针,采用时间扫描方式记录血小板内Ca~(2 )的变化;分别用HPLC/ECD和放射免疫测定法检测5-HT及TXB_2。结果:MN-9202剂量依赖地抑制ADP或凝血酶诱导的血小板聚集,抑制TXA_2的释放并且能有效阻滞激活血小板胞内Ca~(2 )水平的增加。MN-9202 1μmol·L~(-1)能抑制胶原15mg·L~(-1)诱导的5-HT释放反应,但对胶原45mg·L~(-1)诱导的反应无抑制作用。结论:MN-9202阻滞血小板Ca~(2 )内流并抑制血小板花生四烯酸代谢及激活反应。     

Effects of diterpene acids on malondialdehyde generation during thrombin induced aggregation of rat platelets

The effects of diterpene acids (i.e, pimaradienoic acid, kaurenoic acid, hydroxycembratrienoic acid and dihydroxycembratetraenoic acid) on malondialdehyde generation by rat platelets in response to thrombin were studied. All the compounds inhibited the generation of MDA.     

Inhibitory mechanism of ifenprodil tartrate on rabbit platelet aggregation

The effects of dl-erythro-4-benzyl-alpha-(4-hydroxyphenyl)-beta-methyl-l-piperidine-eth anol tartrate (ifenprodil tartrate) on rabbit platelet aggregation in vitro and ex vivo were studied. Ifenprodil tartrate inhibited platelet aggregation in vitro induced by ADP, collagen and epinephrine. It also inhibited 5-hydroxytryptamine (5-HT) uptake into platelets and 5-HT release from platelets. Since these inhibitory effects of ifenprodil tartrate on the functions of rabbit platelets were similar to the effects of imipramine, the effects of ifenprodil tartrate may be due to the stabilizing action of ifenprodil tartrate on the platelet membrane. The platelet aggregation by ADP was significantly inhibited in rabbits after oral administration of ifenprodil tartrate, the maximal plasma level of ifenprodil being reached at 20 ng/ml ex vivo, while the maximal level was only 1/40 of the minimal concentration of ifenprodil tartrate necessary to inhibit platelet aggregation in vitro. These results indicate that factors other than ifenprodil tartrate acting directly on the platelets (e.g., PGI2 which is an endogenous inhibitor of platelet aggregation) are involved in inducing the inhibitory effects of ifenprodil tartrate on platelet aggregation ex vivo. The effects of ifenprodil tartrate on both PGI2 release from the aorta and the inhibitory effects of PGI2 on platelet aggregation in vitro were investigated: PGI2 was found to intensify the inhibitory effects of ifenprodil tartrate on platelet aggregation in vitro, but there was little effect, if any, on PGI2 release. Therefore, it is considered that the ex vivo effects of ifenprodil tartrate might be due to its interaction with endogenous PGI2 in the blood.