Release kinetics of serum cardiac troponin i in ischemic myocardial injury

Objectives: The study was undertaken to evaluate the release kinetics of cardiac troponin I (c-cTn-I) in ischemic myocardial injury.

Design and Methods: The reference range for cTn-I was established by determination of cTn-I in sera and plasma obtained from 622 healthy volunteers (Group 1). cTn-I was compared to: (a) Creatine kinase (CK) MB mass and myoglobin in 12 patients with severe skeletal muscle damage (Group 2); (b) CK-MB activity in 48 patients with myocardial infarction (MI) receiving intravenous thrombolysis (Group 3) (in this group, an additional 43 patients with MI were analyzed separately to characterize cTn-I patterns in thrombolyzed and nonthrombolyzed populations); and in 44 patients with unstable angina (Group 4).

Results: In Groups 1 and 2, no positive results (0.1 μg/L) were obtained. In Group 3, the time-courses of cTn-I were mostly monophasic in form. A pathologic increase occurred earlier in cTn-I than in CK-MB activity (p = 0.0002); the period with increased cTn-I was longer (p = 0.001), the overall sensitivity of cTn-I (93.9%) was higher than that of CK-MB activity (p = 0.00001). cTn-I was more sensitive at admission (p = 0.0004). In additional patients, the cTn-I peak occurred and cTn-I disappeared significantly later in nonthrombolyzed than in the thrombolyzed group. In Group 4, positive tests results were detected in 45% of patients for cTn-I, 16% for CK-MB activity, and 32% for CK-MB mass.

Conclusions: The cTn-I assay appears to be ideally suited for the detection of ischemic myocardial injury in complex clinical situations because of its high specificity; cTn-I indicates myocardial tissue damage in patients with unstable angina and is superior to CK-MB activity and mass in this respect.     

肌钙蛋白T变化对心肌微小损伤的评估意义

目的:评价血清肌钙蛋白T定量测定对心肌微小损伤患者的应用价值。方法:实验于2001-06/2002-05在哈尔滨医科大学附属第一临床医学院实验诊断教研室完成。收集近半年入院接受射频导管消融患者39例,男23例,女16例,平均年龄(34±13)岁,近1个月内有心肌缺血发生或近日内接受过电复率治疗的患者排除在外,糖尿病患者排除在外;正常健康体检者30例,平均年龄(29±18)岁;心肌炎患者20例,平均年龄(10±6)岁,其中男9例,女11例,全部病例均以临床检查结合动态心电图、心脏X射线正位像、心脏彩超和检测磷酸肌酸激酶同工酶等心肌酶为依据,诊断标准按1999年昆明会议修订的标准确诊的;疑似心肌炎患者240例,平均年龄(10±8)岁,其中男110例,女130例,疑似心肌炎按1994年威海会议修订的标准选择;其中39例接受射频导管消融患者插入静脉鞘管后而在插入电极导管前采静脉血做基础值血样本和术后12h采静脉血,其它各组研究对象分别空腹采静脉血2.0mL,所有标本用于磷酸肌酸激酶同工酶和血清肌钙蛋白T测定。结果:20例心肌炎患者血清肌钙蛋白T的变化为(0.190±0.177)μg/L,血清肌钙蛋白T超过参考值的有15例,占75%,磷酸肌酸激酶同工酶为(109.355±66.187)nkat/L,其中有5例磷酸肌酸激酶同工酶超过参考值,占25%,血清肌钙蛋白T升高的百分数与     

Serum cardiac troponin T in cardiac amyloidosis: serial observations in five patients

The most common cause of death of patients suffering from amyloidosis is heart failure and sudden death, and cardiac troponin T (cTnT), a highly specific and sensitive biomarker of myocardial injury, has been reported to be a prognostic marker at presentation. But the relationship between serial measurements of serum cTnT and clinical course of the disease has not been described. An illustrative case was a 55-year-old man with normal renal function presenting with congestive heart failure (CHF), whose initial concentration of cTnT was 0.72 ng/ml. Eight samples of initial endomyocardial biopsy specimens showed the presence of myocyte degeneration and interstitial fibrosis with a small amount of amyloid infiltration. However, the cTnT values remained at 0.69 ng/ml after successful management of CHF, and four months later, a second endomyocardial biopsy revealed diffuse massive amyloid protein deposition. He died of CHF, 9 months after initial presentation. In addition, we present 4 cases of amyloidosis with increased serum cTnT levels. We therefore propose that serial measurements of serum cTnT might be helpful for early diagnosis and prediction of prognosis of patients with amyloidosis.     

肌钙蛋白I和T测定对急性心肌梗塞的诊断意义

目的探讨肌钙蛋白I（cTnI）和肌钙蛋白T（cTnT）测定对急性心肌梗塞（AMI）的诊断价值。方法对52例AMI患者采用免疫层析法进行检测cTnI和cTnT,以对照区和检测区均有显色带者为阳性,并作灵敏度和特异性的比较。结果以胸痛0～3h、4～6h两个时段观察其灵敏度,cTnI为56.7%和96.1%;cT-nT为50.0%和92.3%。特异性cTnI为100%和96.2%;cTnT为100%和91.6%。cTnI灵敏度高于cTnT,特异性cTnI与cTnT之间无显著性差异。结论对AMI急性胸痛患者可同时进行cTnI和cTnT检测,有利于AMI的诊断和治疗。     

肌钙蛋白I和T测定对急性心肌梗塞的诊断意义

目的探讨肌钙蛋白I（cTnI）和肌钙蛋白T（cTnT）测定对急性心肌梗塞（AMI）的诊断价值。方法对52例AMI患者采用免疫层析法进行检测cTnI和cTnT,以对照区和检测区均有显色带者为阳性,并作灵敏度和特异性的比较。结果以胸痛0～3h、4～6h两个时段观察其灵敏度,cTnI为56.7%和96.1%;cT-nT为50.0%和92.3%。特异性cTnI为100%和96.2%;cTnT为100%和91.6%。cTnI灵敏度高于cTnT,特异性cTnI与cTnT之间无显著性差异。结论对AMI急性胸痛患者可同时进行cTnI和cTnT检测,有利于AMI的诊断和治疗。     

Serum neurone-specific enolase as an indicator of stroke volume

Serum neurone-specific enolase (NSE) and computerized tomography (CT) stroke volume were compared in patients admitted within 24 h of an acute stroke. Serum samples were obtained on admission and daily for the next 4 days. Of 163 patients, CT scans revealed 25 with intracerebral haemorrhages, one haemorrhagic infarct and 83 measurable acute infarcts. The serum NSE levels of those with infarcts was significantly higher than in those with haemorrhages at 48 ( P  = 0.0003) and 72 h ( P  = 0.04). The maximum serum NSE value tended to occur later in those with large infarcts ( P  = 0.0035). There was a significant correlation between infarct volume and serum NSE at 48 h ( r  = 0.27, P  = 0.015) and 96 h ( r  = 0.27, P  = 0.015) and with the maximum serum NSE over the 4 days ( r  = 0.36, P  = 0.001). There was no significant correlation between haemorrhage volume and NSE. In conclusion, serum NSE may be a useful marker of infarct volume in studies of therapy in acute stroke. Sampling for NSE should continue, at least in those with large infarcts, for longer than 4 days. Serum NSE cannot be used to distinguish between haemorrhage and infarction in patients with an acute stroke.     

肌钙蛋白对心肌损伤的评估价值

目的:检测血清肌钙蛋白、肌红蛋白以及肌酸激酶评价心肌标志物对判断心肌损伤程度的应用价值。方法:对心脏外科和胸外科手术患者术后48h内不同时间分别采集静脉血,测定心肌肌钙蛋白T(cardiactroponinT,cTnT),肌红蛋白,肌酸激酶MB同工酶(creatinekinase-MB,CK-MB)活性,评价它们在体外循环心脏手术后的应用价值。结果:两组患者术后肌红蛋白都出现明显增高,CK-MB活性也增高,但心脏手术组增高更显著,术后8h为98.8U/L,而胸外科手术组为36.7U/L;心脏手术组术后8,24,48h时相点cTnT均显著增高,分别为0.645,0.656,0.694μg/L,胸外科手术组无显著变化。结论:cTnT在判断心肌损伤程度方面具应用价值。     

血清炎症因子在急性缺血性脑卒中后感染患者中的变化

目的探讨血清炎症因子及美国国立卫生研究院卒中量表(NIHSS)对急性缺血性脑卒中后感染早期诊断的临床价值。方法招募46例急性缺血性脑卒中发生后6 h内入院且无明显感染的患者为研究对象,其中19例患者入院后1周内发生明显的感染纳入感染组,27例未发生感染者纳入无感染组,收集患者入院后6 h、12 h、24 h、3 d和7 d的血液标本测定脂多糖结合蛋白(LBP)、白细胞介素(IL)-6、IL-10和C反应蛋白(CRP)水平,并观察NIHSS评分的变化。结果LBP、IL-6、IL-10和CRP在感染组与无感染组具有明显不同。Logistic回归分析显示入院后6 h时NIHSS、LBP和CRP水平为是否发生感染的独立预测因子(P=0.014、0.041、0.002)。受试者工作特征曲线分析显示,入院后6 h NIHSS的AUC为0.97(P<0.0001),LBP的AUC为0.71(P=0.02),CRP的AUC为0.96(P<0.0001)。结论血清炎症因子水平与NIHSS评分可用于急性缺血性脑卒中后感染的早期监测指标。     

Investigation of release and degradation of cardiac troponin T in patients with acute myocardial infarction

OBJECTIVES: Cardiac troponin T (cTnT) degradation after tissue release is still under debate. Because degradation of cTnT might have consequences on clearance of the molecule from the circulation, but also on the assay performance, the aim of this study was to investigate cTnT release and degradation in serum of AMI patients. DESIGN AND METHODS: Serum samples were collected from 20 patients with AMI diagnosis undergoing rapid revascularization. Intact cTnT and fragments were detected using a combination of immunoprecipitation, SDS-PAGE and Western blotting. RESULTS: The intact cTnT protein was detected only during the first 12 h after the cTnT concentration started to increase above the AMI cut-off value of 0.03 microg/L. Thereafter only fragments with molecular weights ranging from 10 to 30 kDa were detected, with two fragments being most prominent (15 and 25 kDa). CONCLUSIONS: Intact cTnT rapidly disappears from the circulation during the early hours after AMI, but immunoreactive fragments remain present longer. The current cTnT immunoassay detects both intact cTnT and fragments.     

Cardiac troponin T in the diagnosis of myocardial injury.

In the last several decades serum levels of cardiac enzymes and isoenzymes have become the final arbiters by which myocardial damage is diagnosed or excluded. Because conventionally used enzymes are neither perfectly sensitive nor specific, there is need for a new sensitive and cardiospecific marker of myocardial damage. Cardiac troponin T (TnT) is a contractile protein unique to cardiac muscle and can be differentiated by immunologic methods from its skeletal-muscle isoform. An enzyme immunoassay specific for cardiac TnT is now available in a commercial kit for routine use. The biggest advantage of this assay is its cardiospecificity. TnT measurements, however, are also highly sensitive in diagnosis of myocardial injury and accurately discern even small amounts of myocardial necrosis. TnT measurements are, therefore, particularly useful in patients with borderline CK-MB and in clinical settings in which traditional enzymes fail to diagnose myocardial damage efficiently because of lack of specificity--for example, perioperative myocardial infarction or blunt heart trauma. TnT release kinetics reveal characteristics of both soluble, cytoplasmic, and structurally bound molecules. It starts to increase a few hours after the onset of myocardial damage and remains increased for several days. TnT allows late diagnosis of myocardial infarction. The diagnostic efficiency remains at 98% until 6 d after the onset of infarct-related symptoms. TnT is also useful in monitoring the effectiveness of thrombolytic therapy in myocardial infarction patients. The ratio of peak TnT concentration on day 1 to TnT concentration at day 4 discriminates between patients with successful (greater than 1) and failed (less than or equal to 1) reperfusion. TnT measurements are very sensitive and specific for the early and late diagnosis of myocardial damage and could, therefore, provide a new criterion in laboratory diagnosis of the occurrence of myocardial damage.     

Role of cardiac troponin I in the evaluation of myocardial injury

Cardiac troponin I (cTnI) is highly specific for cardiac muscle. In this study, we compared the utility of CK and CK-MB index versus cTnI in the assessment of myocardial infarction in 155 patients being evaluated for myocardial damage. As a cardiac marker for MI, Troponin I seems to be superior to CK-MB. In the subset of patients with renal disease, cTnI has definite advantages over CK-MB. In addition, the use of cTnI has the potential to replace the measurement of lactate dehydrogenase isoenzymes. J. Clin. Lab. Anal. 12:276–279, 1998. © 1998 Wiley-Liss, Inc.     

不稳定心绞痛患者血清C 反应蛋白与肌钙蛋白的变化及对普伐他汀的影响

目的　观察不稳定心绞痛(UAP)与血清C - 反应蛋白(CRP)、肌钙蛋白(cTnT)的关系,并观察普伐他汀对两者的影响。方法　测定42 例UAP 患者(UAP 组)、40 例稳定型心绞痛患者(SAP 组)和对照组血清CRP、cTnT 浓度,并进行比较,同时测定比较UAP组、SAP组应用普伐他汀治疗前后的CRP、cTnT水平。结果　UAP组患者血清CRP、cTnT 浓度显著高于SAP组和对照组(P<0.05,P<0.01); UAP组应用普伐他汀治疗后,CRP、cTnT水平显著下降(P< 0. 01),而SAP组下降不明显(P> 0. 05)。结论　测定CRP和cTnT可以预测急性冠状动脉综合征的病变稳定程度和心血管事件发生的危险度,普伐他汀能有效地降低UAP患者的CRP、cTnT水平。     

新生儿窒息后血清心肌肌钙蛋白T和心肌酶检测结果分析

目的探讨新生儿窒息后血清心肌肌钙蛋白T(cTnT)和心肌酶浓度变化与窒息程度的相关性。方法采用日立7600生化分析仪和罗氏2010电化学发光免疫分析仪检测窒息新生儿血清心肌酶和cTnT浓度。结果新生儿窒息后血清心肌酶活性显著增高,其增高程度与新生儿窒息程度呈正比;血清cTnT浓度增高与新生儿窒息后是否发生心血管并发症呈正相关。结论窒息并发心力衰竭的新生儿通过检测血清cTnT和心肌酶能及早发现心肌损害,并判断其严重程度。     

高敏肌钙蛋白T对肾脏受损的急性心肌梗死患者诊断准确性研究

目的探讨高敏肌钙蛋白T(hs-cTnT)对肾脏受损的急性心肌梗死(AMI)患者诊断准确性。方法根据估算肾小球滤过率(eGFR)不同将纳入研究的1 934例出现胸痛的患者进行分组,分别为eGFR≥90 mL/(min·1.73 m~2)组[慢性肾脏病(CKD)Ⅰ期]689例、eGFR 60~90 mL/(min·1.73 m~2)组(CKDⅡ期) 889例、eGFR 30~60 mL/(min·1.73 m~2)组(CKDⅢ期) 283例和eGFR 30 mL/(min·1.73 m~2)组(CKDⅣ期) 73例。比较各组受试者工作特征(ROC)曲线的确定阈值与第99百分位数对应诊断性能差异。结果在eGFR 30 mL/(min·1.73 m~2)、eGFR 30~60 mL/(min·1.73 m~2)及eGFR60~90 mL/(min·1.73 m~2)中,ROC确定阈值与第99百分位数对应敏感度、特异度、阳性预测值、阴性预测值比较,差异均有统计学意义(P 0.01)。结论若需使用hs-cTnT准确诊断肾脏受损的AMI患者,其ROC阈值需结合eGFR。     

Serum creatinine as an indicator of renal function after spinal cord injury

This study was conducted to determine (1) if serum creatinine levels (SCL) in spinal cord injury (SCI) patients are influenced by neurologic level of lesion, sex, age, or time since injury, and (2) if SC values are a sensitive indicator of renal function (as reflected by renal plasma flow [RPF]) in these patients. The overall SC mean and SD were 0.9 +/- 0.2mg/dl (n = 141). There was no difference in SC values between patients with higher injuries (T-6 or above) and patients with lower injuries (T-7 or below), nor was there any difference between patients with lesions less than 3 months, 10-14, 22-26, 34-38, 46-50, or 58-62 months in duration. Age and gender each accounted for less than 5% of the variation in SC. There was no significant correlation between RPF and SC (unless the patient also had moderate or severe pyelocaliectasis) nor between change in serum RPF (from the previous examination, usually 12 months earlier) and change in SC, suggesting that SCL does not reflect the functional status of the kidney in these patients.     

Different time frames for the occurrence of elevated levels of cardiac troponin T and C-reactive protein in patients with acute myocardial infarction.

The baseline plasma level of C-reactive protein (CRP) is considered to be a parameter for risk stratification in patients with an acute coronary syndrome, independent of the level of cardiac troponin T (cTnT) or cardiac troponin I. However, myocardial tissue necrosis following prolonged arterial occlusion also induces release of CRP. Both phenomena may have their own kinetic behaviour with respect to changes in concentration of CRP. Therefore, in this study the time frame after onset of symptoms for measurement of CRP as an independent parameter is established. For this purpose, we evaluated patients with proven myocardial damage due to acute myocardial infarction (AMI) with respect to changes of creatine kinase (CK)-MB mass, cTnT and CRP during 24 hours after onset of symptoms. Our results show that two subgroups can be discerned in patients with AMI: those with initially normal and those with already elevated concentration CRP on admission. Furthermore, based on the results of this study we conclude that for use of CRP as an independent prognostic parameter in patients with acute coronary syndrome, CRP should be measured in blood samples drawn as early as possible after the onset of symptoms to avoid contribution of a process of myocardial tissue necrosis, whereas estimation of cTnT should be performed at 6-12 hours.     

高敏肌钙蛋白T在急性心肌缺血诊断中的意义

目的评价高敏肌钙蛋白T（high—sensitivity troponinT,hs—TnT）在急性心肌缺血（AMI）中的应用价值。方法分析146例入院检查者,其中急性心梗患者56例,不稳定型心绞痛患者47例及正常体检者43例,入院时的即刻样品hs—TnT和CK,CKMB指标。结果确诊为AMI患者的hs．TnT、CK、CKMB阳性检出率分别为87．5％,51．8％,75％,均高于不稳定型心绞痛正常人（P〈0．05）。AMI早期患者血清中hs．TnT阳性率高于心肌酶谱指标。结论与CK、CKMB指标相比,hs．TnT灵敏度与特异性均较高,能够减少AMI的误诊和漏诊,是AMI早期诊断的可靠指标。