丹酚酸B体外干预骨髓间充质干细胞分化过程中cTnT的表达

[目的]观察丹酚酸B(SalB)体外干预骨髓间充质干细胞(MSCs)后细胞形态及心肌特异性蛋白肌钙蛋白T(cTnT)的表达。[方法]培养、纯化及鉴定MSCs,用SalB、5-氮胞苷组(5-aza)、SalB联合5-aza(SalB 5-aza)分别定向诱导分化,观察此过程中MSCs的形态学变化并采用免疫细胞化学法鉴定诱导后MSCs心肌特异性肌钙蛋白T(cTnT)的表达。[结果]诱导后的MSCs体积增大,增殖减慢,并出现肌管样结构;免疫细胞化学结果显示诱导后MSCs表达心肌特异性蛋白cTnT。[结论]SalB在体外定向诱导MSCs分化为心肌细胞的过程中发挥了一定的作用。     

急性心肌梗死应用心肌肌钙蛋白T检测的临床分析

目的总结笔者所在医住院部急性心肌梗死（AMI）患者的诊断资料,评价和分析急性心肌梗死应用心肌肌钙蛋白T（cTnT）检测的应用诊断价值。方法收集住院部急性心肌梗死的临床资料（包括临床病史、心电图、心肌酶谱、心脏彩色超声）,对每例的首发症状、起病时间、既往史等进行归类和总结,分析比较cTnT与肌酸肌酶同工酶CK—MB、心电图（EGG）检测结果,进行统计学分析。结果cTnT检测对早期急诊AMI（2—6h）的阳性率不高（74．42％）,在发病时间6h至8d内,具有较高特异性和准确性（其阳性率〉90．0％）,明显高于ECG、CK—MB检测的阳性率,差异具有显著性;cTnT检测对于心内膜微小心肌损伤、心肌毒性物质及机械损伤等原因所致的心脏病患者（9例）不具有明显的特异性。结论cTnT检测用于急性心肌梗死的诊断具有灵敏度高、特异性强、持续时间长、报告结果快速准确等特点,效果明显优于ECG、CK—MB检测,是快速确诊AMI较为理想的生化标志物,与其联合检测可以提高早期AMI的检出率及诊断时间窗。     

Evaluation and risk stratification of acute coronary syndromes using a low cut-off level of cardiac troponin T, combined with CK-MB mass determination

OBJECTIVES: To study the usefulness of combined cardiac Troponin T (cTnT) and CK-MB mass determinations in risk stratification of acute coronary syndromes. DESIGN AND METHODS: Blood samples for cTnT and CK-MB mass were collected at arrival and 4, 8, and 12-24 later in 301 consecutive patients with recent acute chest pain (ACP). Data were also collected for cardiac events. RESULTS: Combined cardiac mortality/nonfatal myocardial infarction over a period of 15 months was lowest in patients with <0.04 microg/l cTnT and -<5.0 microg/l CK-MB mass intermediate in those with elevated cTnT but normal CK-MB mass and highest when both markers were elevated, in absence of early reperfusion. CONCLUSION: The use of a low cut-off point of cTnT, combined wit CK-MB mass determination, offers a good strategy for risk stratification of ACP patients.     

Ablation of p21-activated kinase-1 in mice promotes isoproterenol-induced cardiac hypertrophy in association with activation of Erk1/2 and inhibition of protein phosphatase 2A

Earlier investigations in our lab indicated an anti-adrenergic effect induced by activation of p21-activated kinase (Pak-1) and protein phosphatase 2A (PP2A). Our objective was to test the hypothesis that Pak-1/PP2A is a signaling cascade controlling stress-induced cardiac growth. We determined the effects of ablation of the Pak-1 gene on the response of the myocardium to chronic stress of isoproterenol (ISO) administration. Wild-type (WT) and Pak-1-knockout (Pak-1-KO) mice were randomized into six groups to receive either ISO, saline (CTRL), or ISO and FR180204, a selective inhibitor of Erk1/2. Echocardiography revealed that hearts of the Pak-1-KO/ISO group had increased LV fractional shortening, reduced LV chamber volume in diastole and systole, increased cardiac hypertrophy, and enhanced transmitral early filling deceleration time, compared to all other groups. The changes were associated with an increase in relative Erk1/2 activation in Pak-1-KO/ISO mice versus all other groups. ISO-induced cardiac hypertrophy and Erk1/2 activation in Pak-1-KO/ISO were attenuated when the selective Erk1/2 inhibitor FR180204 was administered. Immunoprecipitation showed an association between Pak-1, PP2A, and Erk1/2. Cardiac myocytes infected with an adenoviral vector expressing constitutively active Pak-1 showed a repression of Erk1/2 activation. p38 MAPK phosphorylation was decreased in Pak-1-KO/ISO and Pak-1-KO/CTRL mice compared to WT. Levels of phosphorylated PP2A were increased in ISO-treated Pak-1-KO mice, indicating reduced phosphatase activity. Maximum Ca²⁺-activated tension in detergent-extracted bundles of papillary fibers from ISO-treated Pak-1-KO mice was higher than in all other groups. Analysis of cTnI phosphorylation indicated that compared to WT, ISO-induced phosphorylation of cTnI was blunted in Pak-1-KO mice. Active Pak-1 is a natural inhibitor of Erk1/2 and a novel anti-hypertrophic signaling molecule upstream of PP2A.     

心脏肌钙蛋白T在急性心肌梗死中的应用价值

目的 探讨血清肌钙蛋白T(cTnT)在急性心肌梗死(AMI)后的释放特点及其对AMI溶栓后的疗效判定。方法 采用酶联免疫法对28例AMI患者进行动态血清cTnT观察,同时测定CK及CK-MB。结果 溶栓2小时阳性率为67.9％、发病8小时至5天为100％、发病7、9、11、13、15、17、19天分别为92.9％、82.1％、67、9％、60.7％、39.3％、21.4％、7.1％。明显比CK和CK-MB持续时间长。cTnT诊断急性心肌梗死的敏感性为100％。溶性再通组15例呈双峰曲线,4例呈单峰曲线,双峰者首峰与次峰比大于2,单峰都在24小时以内出现。未通组双峰3例,单峰6例,双峰者首峰与次峰比不大于2,单峰多在4～5天内出现。把首峰与次峰之比(或第24小时内峰值与第4日峰值之比)大于2,作为溶栓再通指标的敏感性为89.5％,特异性为100％。结论 血清中cTnT动态变化对AMI的诊断及溶栓治疗效果的评定均有一定的价值。     

心肌肌钙蛋白的研究和应用

心肌肌钙蛋白是近年来国内外研究的热点,因其高度的心肌特异性、敏感性,使它成为临床快速诊断急性心肌梗死的最有价值的指标,本文就肌钙蛋白的结构性质、检测方法、临床应用的研究进展等作一综述。     

心肌钙蛋白R在急性心肌梗塞时的诊断临界值探讨

目的应用临床诊断性能（ROC）曲线,探讨急性心肌梗死（AMI）时心肌损伤标记物心肌钙蛋白T（cTnT）在不同时间内的临床诊断临界值。方法测定非AMI患者和AMI患者入院后2h内、24h内、48h内的血浆或血清cTnT、浓度,通过临床诊断性能ROC曲线特性分析cTnT在AMI不同时间内的临床诊断临界值。结果非AMI患者cTnT、的浓度不随时间发生变化,而AMI患者的cTnT浓度随时间呈动态变化,且不同时间内的诊断临界值不同,即入院2h内、24h内和48h内其初筛临界值分别为0．031μg／L、0.039μg／L和0．030μg／L;最佳临界值分别为0．038μg／L、0．045μg／L和0．038μg／L;确诊临界值分别为0．046μg／L、0058μg／L和0．056μg／L;其ROC曲线下面积（AUC）分别为0．970、0．975和0．938。结论AMI患者的cTnT浓度随时间呈动态变化,不同时间内cTnT的临床诊断临界值不同。     

H-FABP、NT-proBNP、CRP、cTnT在ACS患者预后中的评估价值

目的探讨分析H-FABP、NT-proBNP、CRP、cTnT在ACS患者预后中的评估价值。方法 96例ACS患者根据随访1年内患者是否发生不良心血管事件将所有患者分为预后不良组（35例）与对照组（61例）。于患者入院后检测H-FABP、NT-proBNP、CRP、cTnT四项指标的水平,并于出院后进行为期1年的随访,绘制受试者工作特性曲线来测定上述四项指标对ACS患者预后评估的准确性,并找出出院后发生不良心血管事件的危险因素。结果入院时预后不良组H-FABP、NT-proBNP、CRP、cTnT水平均明显高于对照组（P〈0.05）;H-FABP、NT-proBNP、CRP、cTnT检测对预测心血管不良事件的ROC曲线下面积与临界值分别为0.811、40.95μg/L,0.749、1342.98ng/L,0.788、9.69mg/L,0.812、0.78μg/L;COX单因素回归分析显示H-FABP、NT-proBNP、CRP及cTnT水平的升高是ACS患者发生心血管不良事件的危险因素（P〈0.05）。结论 H-FABP、NT-proBNP、CRP、cTnT对ACS患者的预后有着较高的评估价值,值得推广。     

阿霉素导致兔血清肌钙蛋白T变化的实验研究

目的 观察逐渐增量注射阿霉素(ADR)对兔血清心肌肌钙蛋白T(cTnT)动态变化的影响,籍以了解ADR对心脏毒性的量效关系.方法 将新西兰兔18只,随机分成阿霉素(ADR)组(10只)和对照组(8只).ADR组每周从兔耳静脉注射ADR 1次(2mg/kg,用生理盐水配制成1mg/ml),共6次.对照组注射生理盐水.两组分别在第1、28、35、42天(ADR累积量为0、8、10、12 mg/kg)抽血检测cTnT.结果 当阿霉素的累积达到10mg/kg后,cTnT明显升高,且与ADR的累积量正相关(P＜0.005,r=0.79).结论 动态检测血清cTnT的变化可以反映阿霉素对心脏毒性的严重程度.