Roberts R, Gowda K S, Ludbrook P A, Sobel B E
Am J Cardiol. 1975 Oct 6;36(4):433-7. doi: 10.1016/0002-9149(75)90890-5.
Creatine phosphokinase (CPK) isoenzyme determinations are useful in the diagnosis of myocardial infarction. However, until suitably sensitive and precise quantitative procedures became available, the diagnostic specificity of serum CPK isoenzyme elevations could not be thoroughly examined. In this study an assay procedure capable of accurately determining activity of individual CPK isoenzymes even in serum samples with normal total CPK activity was employed to obtain two types of information. First, CPK isoenzyme profiles were examined in extracts of a spectrum of human tissues obtained at operation to determine whether the isoenzyme associated with myocardium is presented in other human tissues in quantities sufficient to produce increased activity in serum. In addition, CPK isoenzymes were analyzed quantitatively in serial serum samples from 50 hospitalized control subjects, 100 patients with acute myocardial infarction, 100 patients undergoing non-cardiac surgery and 50 patients undergoing cardiac catheterization to determine whether insult to tissues other than the heart is associated with increased "myocardial" CPK isoenzyme activity in serum. Results from analyses of tissue extracts indicated that myocardium is the only tissue surveyed containing sufficient MB CPK to account for substantial increases in serum MB activity. Results from analyses of serial serum samples indicated that MB CPK activity levels are consistently elevated after myocardial infarction, averaging 0.089 IU/ml. However, after cardiac cathetrization or noncardiac surgery peak serum MB activity remains low, averaging only 0.004 IU/ml despite marked elevations in total serum CPK activity. Thus, elevated serum MB CPK activity is a highly specific as well as sensitive criterion of myocardial injury.
肌酸磷酸激酶（CPK）同工酶测定对心肌梗死的诊断很有用。然而，在获得灵敏且精确的定量检测方法之前，血清CPK同工酶升高的诊断特异性无法得到充分检验。在本研究中，采用了一种即使在总CPK活性正常的血清样本中也能准确测定单个CPK同工酶活性的检测方法，以获取两类信息。首先，检测了一系列手术获取的人体组织提取物中的CPK同工酶谱，以确定与心肌相关的同工酶在其他人体组织中的含量是否足以使血清活性升高。此外，对50名住院对照受试者、100名急性心肌梗死患者、100名接受非心脏手术的患者和50名接受心导管检查的患者的系列血清样本进行了CPK同工酶定量分析，以确定除心脏外的其他组织受损伤是否与血清中“心肌”CPK同工酶活性增加有关。组织提取物分析结果表明，心肌是所检测的唯一含有足够MB CPK以解释血清MB活性大幅增加的组织。系列血清样本分析结果表明，心肌梗死后MB CPK活性水平持续升高，平均为0.089 IU/ml。然而，在心导管检查或非心脏手术后，尽管血清总CPK活性显著升高，但血清MB活性峰值仍然很低，平均仅为0.004 IU/ml。因此，血清MB CPK活性升高是心肌损伤的一个高度特异性和敏感性的标准。
