Creatine kinase and lactate dehydrogenase isoenzymes in serum of patients suffering burns, blunt trauma, or myocardial infarction

Medical records of 53 burn and trauma patients were reviewed to assess the possibility of myocardial damage. Except for electrophoretically detectable creatine kinase MB isoenzyme, none showed evidence of myocardial injury. Lactate dehydrogenase isoenzyme tests, electrocardiograms, myocardial pyrophosphate scans, clinical course, and results of (two) autopsies were all negative for myocardial necrosis or ischemia. Types of patient, number, mean peak value (U/L) for serum creatine kinase, and ranges of percentage MB isoenzyme were as follows. Burns from direct electrical contact: 28, 16 600, 0-29; electrical flash or other thermal burns: 10, 4340, 0-22; blunt trauma (mostly from automobile accidents): 15, 3430, 0-18; myocardial infarction: 57, 1520, 4-46. Evidently creatine kinase MB isoenzyme is nonspecific in burn and trauma patients and should not be the only test result used to assess myocardial involvement.     

Diagnostic efficiency of lactate dehydrogenase isoenzymes in serum after acute myocardial infarction

Diagnostic efficiency of lactate dehydrogenase isoenzymes were studied in 117 consecutive patients admitted with some symptoms of acute myocardial infarction. The results of lactate dehydrogenase isoenzyme tests were not available to the physicians, who diagnosed the patients according to criteria based on clinical symptoms, electrocardiographic findings and changes in three serum enzymes. Acute myocardial infarction was diagnosed in 41 patients. The diagnostic efficiency of lactate dehydrogenase isoenzyme 1 and the various ratios between this and the other isoenzymes were compared using receiver operating characteristic curves and logistic discriminant analysis. Lactate dehydrogenase isoenzyme 1 was the best parameter on the second day after admission. On that day, calculating the various ratios between isoenzyme 1 and the other isoenzymes did not improve discrimination.     

Lactate dehydrogenase isoenzyme-1/total ratio: accurate for determining the existence of myocardial infarction

We have gradually revised our medical protocols for measuring creatine kinase MB isoenzyme (CK-MB) and lactate dehydrogenase isoenzyme-1 (LD-1) because of identifiable problems in the use of an interpretation of CK-MB isoenzyme associated with slowly evolving or small myocardial infarct, the use of thrombolytic therapy, or burn and trauma, each of which affects the rate of appearance and composition of isoenzymes present. Despite recent evidence of the efficacy of LD-1 isoenzyme measurement in the first 12 to 24 h of myocardial infarction, this test is not widely used because of overstated assumptions about the value of CK-MB. Here we studied the adequacy of the current isoenzyme assays by determining the value of CK-MB and LD-1 at optimum serum sampling times and establishing the contribution of individual and combined predictors to diagnostic efficiency. We conclude that the LD-1/total LD activity ratio in serum is superior to measurement of CK-MB or LD-1, or both, in the diagnosis of acute myocardial infarction. Moreover, this ratio is most valuable when interpretation of the result for CK-MB isoenzyme is equivocal in patients with small or evolving myocardial infarcts.     

3.0T心脏磁共振对肥厚性心肌病心肌纤维化与心肌损伤标志物的关系研究

目的运用3.0 T心脏磁共振(CMR)延迟强化(LGE)技术对肥厚性心肌病(HCM)心肌纤维化进行定量检测,并获得LGE与心肌标志物即心肌代谢酶的关系,从而探究HCM患者心肌标志物升高是否与心肌纤维化造成的心肌细胞损伤有关。方法纳入34例HCM患者(HCM组)与20例健康志愿者(正常对照组)。两组均行3.0 T CMR扫描,包括短轴位心脏电影及LGE序列。心脏功能用短轴为心脏电影序列测定;运用LGE序列测定HCM与正常对照组的LGE参数,包括总LGE率、LGE体积及LGE质量;测定与心肌损伤程度有关的血清心肌标志物含量,包括肌酸激酶同工酶、肌钙蛋白。采用独立样本t检验及Pearson积矩相关对心肌标志物及LGE参数进行统计分析。结果 HCM组肌酸激酶同工酶、肌钙蛋白均大于临床正常范围。通过LGE检测,HCM组的LGE参数,包括总LGE率、LGE体积及LGE质量均大于正常对照组[分别为(18.95±9.87)%vs.(50.82±14.18)%、(8.50±4.50)ml vs.(86.26±41.99)ml及(9.00±4.80)g vs.(90.58±44.11)g,均P<0.05]。Pearson积矩相关证明,HCM组肌酸激酶同工酶与总LGE率、LGE体积呈正相关(r值分别为0.759、0.448,P值分别为0.000、0.008)。肌钙蛋白与总LGE率、LGE体积呈正相关(r值分别为0.647、0.578,P值均为0.000)。结论 3.0 T CMR LGE技术可用于肥厚性心肌病心肌纤维化的定量检测,HCM患者心肌标志物与心肌的LGE率呈正相关,表明心肌纤维化造成的心肌细胞损伤可能导致心肌细胞内的代谢酶类即心肌标志物释放,从而影响心肌的代谢功能,最终造成心脏功能损伤。     

Detection of cardiac-specific creatine kinase isoenzyme in sera with normal or slightly increased total creatine kinase activity.

We describe a spectrophotometric kinetic assay for detecting creatine kinase MB isoenzyme activity in the 1 to 10 U/liter range. The MB isoenzyme was isolated [Clin. Chem. 20, 36 (1974)] and assayed (Rosalki method) with an Abbott ABA-100. Good reproducibility was demonstrated for MB isoenzyme activities near 1 U/liter (CV = 2.6%). Sera with normal or slightly increased total creatine kinase activity were evaluated. Sera of 14 patients with acute myocardial infarction contained, per liter, 84 to 236 U of total creatine kinase activity and 4.6 to 28.0 U of isoenzyme MB activity; corresponding ranges for sera from healthy lab technicians and patients with noncardiac disease were 36 to 277 and 0 to 2.6 U. MB isoenzyme activity for infarction patients rose and fell sharply within three days after the infarction. Atypical time-course patterns, MB isoenzyme activity remaining abnormally great for five days, were observed in serum from patients with prolonged atrial fibrillation and congestive heart failure or cardiomyopathy; the BB isoenzyme (1 to 5 U/liter) was also detected in sera of such patients but was absent in sera from infarcation patients. Quantification of column-isolated MB by the assay described is rapid, easy, specific, and extremely sensitive for measuring MB in the 1 to 10 U/liter range.     

Detection of creatine kinase BB isoenzyme in sera of patients undergoing aortocoronary bypass surgery.

Creatine kinase BB isoenzyme (CK-BB) was detected intraoperatively in 22 of 25 patients undergoing aortocoronary bypass surgery, both in the coronary sinus and in the mixed venous blood. In a group of 10 patients in whom selective intracavitary profound hypothermic arrest was used, CK-BB values were lower than in another group of 10 patients, in whom controlled ventricular fibrillation with moderate total body hypothermia was instituted. This latter group also had higher levels of CK-MB. Patients who developed acute myocardial infarction immediately prior to or during the surgical intervention had the highest CK-BB values. This enzyme appeared as early as 15 minutes after the institution of cardiopulmonary bypass and disappeared within 6 hours. It is considered that part of the BB isoenzyme in serum of patients undergoing heart surgery is of myocardial origin.     

Mass concentration of creatine kinase MB isoenzyme and lactate dehydrogenase isoenzyme 1 in diagnosis of perioperative myocardial infarction after coronary bypass surgery

Recent advances in methodology allow the mass concentration of creatine kinase MB isoenzyme (CK-MB), and of lactate dehydrogenase isoenzyme 1 (LD1) to be determined quickly and easily as routine, emergency tests. We evaluated these tests as diagnostic criteria of perioperative myocardial infarction (PMI) after coronary bypass surgery. These tests were compared with the usual measurements of CK-MB activity by immunoinhibition and LD1 by electrophoresis and with other biological markers of myocardial infarction such as total CK, total LD, and aspartate aminotransferase. Sixty-one patients who underwent coronary bypass grafting were followed pre- and postoperatively by enzyme determinations and electrocardiography; a subgroup was monitored by myocardial scintigraphy. CK-MB mass appeared to be the best marker of PMI during the first 48 h, although LD1 was the marker of choice from days 2 to 4.     

心肌坏死标志物联合检测在急性心肌梗死早期诊断及鉴别中的意义

目的探讨心肌坏死标志物联合检测在急性心肌梗死早期诊断及鉴别中的意义。方法选取20lO年12月至2013年5月我院收治的90例患者,其中45例被确诊为急性心肌梗死,设为观察组,其余45例疑似急性心肌梗死的患者经过心电图、彩色多普勒超声心动图检查未见异常,最终确定为非急性心肌梗死患者,设为对照组。对两组患者进行酶活性、心肌蛋白及同工酶电泳检查。采用免疫抑制法测定肌酸激酶（CK）、肌酸激酶同工酶（CK—MB）,采用电化学发光法检测肌钙蛋白l（cTnI）和肌红蛋白（MYO）,记录CK、CK—MB、cTnI和MYO等含量,比较观察组患者心肌标志物不同时间的变化并进行统计学分析。结果与对照组比较,观察组患者血清CK、CK—MB、cTnI及MYO含量升高明显,其中CK、MYO含量升高最为显著（P〈0．05）。CK、CK—MB在发病3-6h后快速升高,均于24h左右达高峰,经治疗3-5天后恢复;cTnI前24h与CK—MB同步,但在血中维持时间较长;MYO在发病后12h发生异常,12h内达到峰值（P〈0．05）。结论心肌坏死标志物联合检测可以提高急性心肌梗死检出率,有助于急性心肌梗死早发现、早诊断和早治疗。     

Improved column method for separating lactate dehydrogenase isoenzymes 1 and 2

Lactate dehydrogenase (LD) isoenzymes 1 and 2 in human serum were separated on a column of diethylaminoethyl-Sephadex. Samples layered on mini-columns were eluted with buffered sodium chloride (100, 150, and 200 mmol/liter). Lactate dehydrogenase activity in column effluents was measured by the Wacker method, and their isoenzyme content was evaluated by electrophoresis on polyacrylamide gel. Results for column-fractionated LD-1 and LD-2 were expressed in two ways: LD-1/LD-2 ratios and total LD-1 + LD-2 activities. The former is a more specific indicator of myocardial infarction than the latter. Sera from 10 patients with acute myocardial infarction (increased creatine kinease isoenzyme MB activity) exhibited ratios in the range of 0.92 to 1.56, ratios for 10 patients without heart disease (normal creatine kinase MB) ranged from 0.33 to 0.69.     

Use of creatine kinase MB isoenzyme for diagnosing myocardial infarction when total creatine kinase activity is high

The usefulness of measuring creatine kinase MB isoenzyme for diagnosing myocardial infarction when activities of total creatine kinase are very high is unclear. We conducted a retrospective study in an urban hospital that serves a largely indigent population. We concentrated on 146 patients whose creatine kinase activity was greater than 1000 U/L (upper limit of normal: 165 U/L for women and 225 U/L for men), with MB isoenzyme greater than 10 U/L and less than 5% of total creatine kinase. The positive predictive value of MB isoenzyme (isoimmune method) values greater than 10 U/L was between 11.6% and 56.8% when the value for total creatine kinase exceeded 1000 U/L. Using different values (MB greater than 4% of total creatine kinase) as positive for myocardial infarction would have resulted in far fewer false-positives, but 10 cases of myocardial infarction would have been missed. The most appropriate cutoff value for MB isoenzyme in this population (total creatine kinase greater than 1000 U/L) was found to be greater than 2% of total creatine kinase.     

Secondary myocardial injuries

This study identifies a subgroup of critically ill patients most likely to develop at least creatine kinase-myocardial isoenzyme (CK-MB) evidence of acute myocardial injury. This group is composed of patients with shock syndromes associated with some combination of anemia, hypoxemia, hypercarbia, acidemia, lactic acidosis, and hypotension. The mechanism of this secondary myocardial injury in shock is not clear but may be multifactorial. Certainly subgroups of patients admitted with critical illnesses may have CK-MB abnormalities usually associated with acute myocardial injury.     

Atypical patterns of lactate dehydrogenase isoenzymes in acute myocardial infarction

Total lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum and LD isoenzymes were quantified in 190 patients with acute myocardial infarction (AMI) 24, 48, and 72 h after admission. In 90% of the 570 blood specimens an LD isoenzyme pattern typical of AMI (LD-1/LD-2 greater than 0.76) was found. The other 56 blood specimens showed an LD isoenzyme pattern atypical of AMI (LD-1/LD-2 less than 0.76). They were divided into three groups: 28 specimens with isomorphic pattern (relative increase in all five LD isoenzymes); 18 with relatively increased LD-3 proportion (greater than 35%); and 10 specimens with increased LD-5 proportion (greater than 10%). No difference was found in mean total LD activity in serum between the typical isoenzyme group and the three atypical groups. The LD isomorphic pattern was found in 60% of AMI patients complicated by cardiogenic shock. Fifty percent of AMI patients admitted with pulmonary edema showed increased LD-3 proportion and half of the patients with AMI and congestive heart failure, predominant right, demonstrated increased LD-5 proportion. We conclude that although most patients with AMI present at diagnosis with a typical LD isoenzyme pattern, it is important to recognize that some may present with atypical LD isoenzyme patterns, which may be associated with specific AMI complications.     

AOPP患者血液流变学和心肌酶含量变化的相关性研究

目的探索急性有机磷农药中毒(Acute Organophosphorus Pesticide Poisoning,AOPP)患者血液流变学变化和心肌酶含量变化的关系。方法对32例重度AOPP患者血液流变学指标(血浆粘度、红细胞聚集指数、红细胞变性能力)和心肌酶含量(CK-MB、LDH)进行连续检测,并对血液流变学指标和心肌酶含量的变化进行相关性分析。结果同健康对照组相比,中毒组患者早期血浆粘度、红细胞聚集指数、CK-MB、LDH均明显升高,红细胞变性能力明显降低(P<0.01):随病情改善血液流变学指标、心肌酶含量呈逐渐恢复趋势。结论AOPP患者心肌酶的变化与血液高粘滞状态有明显的相关性。     

Comparison of enzyme immunoassay and immunoprecipitation for creatine kinase MB in diagnosis of acute myocardial infarction

We compared the clinical performance of measuring creatine kinase (EC 2.7.3.2) isoenzyme MB by use of an enzyme immunoassay (Enzygnost CK-MB, Behring Diagnostics) with an immunoprecipitation method (Isomune-CK, Roche Diagnostics) for the diagnosis of acute myocardial infarction. Sera from 80 patients admitted to the coronary care unit because of chest pain were examined: 40 who had this diagnosis of myocardial infarction, and 40 in whom it was ruled out. In addition, sera from 40 apparently healthy individuals were examined. The clinical sensitivity and specificity of these methods were evaluated by use of receiver operating characteristic curves. We conclude that for clinical efficiency, this enzyme immunoassay is slightly superior to the immunoprecipitation assay we used, because of its greater analytical sensitivity and precision for measuring the mass of the isoenzyme.     

New manual and automated method for determining activity of creatine kinase isoenzyme MB, by use of dithiothreitol: clinical applications.

The method is based on the selective activating capacity of dithiothreitol on creatine kinase isoenzyme MB, after isoenzyme MM is activated by glutathione. Isolated isoenzymes MM and MB of human and canine origin were assayed individually and in mixtures of known activities. When glutathione was present in the assay medium the activity of each isoenzyme could be measured individually, but glutathione did not activate isoenzyme MB if it was present in a mixture with MM. Dithiothreitol, added to the serum before assay, activated the isoenzyme MB in the mixture. Values for MB activities obtained for isolated isoenzyme MB and for the isoenzyme mixture after dithiothreitol was added averaged 110 and 111 U/liter, respectively (r = 0.998; y = 1.007 x + 0.298; n = 10). In the serum of 40 patients with documented acute transmural myocardial infarction, the mean proportion of isoenzyme MB activity measured in this way was 5.5% (coefficient of variation, 7.7%). Isoenzyme MB activities measured by use of dithiothreitol compared well with those obtained by conventional electrophoresis/spectrophotometry (r = 0.998; y = 1.09x -0.65) and spectrofluorometry (r = 0.996; y = 1.10 x + 0.80). The assay of MB activity by the dithiothreitol method was automated, by use of an Abbott Bichromatic Analyser and a Calbiochem Super-Stat Pack Kit. In 60 isoenzyme MB determinations the manual and automated method correlated well (r = 0.990; y = 1.0x -1.36). The simplicity of isoenzyme MB determination by use of dithiothreitol and its ease of automation allow routine monitoring of the isoenzyme activity in patients with ischemic heart disease.     

Serum CK-MB isoenzyme after aortic and mitral valve replacements

A release of the MB fraction of creatine kinase (CK) enzyme into the serum due to myocardial manipulation and trauma occurs in patients undergoing cardiac surgery. Thus, the appearance of CK-MB activity as such is not sufficient to indicate of perioperative myocardial infarction. The mean (+/- SD) serum CK-MB isoenzyme level was 95 +/- 103 U/l 18 hours after aortic or mitral valve replacement in 76 patients. Thirteen patients undergoing closure of an atrial septal defect served as controls. They had a significantly lower (p less than 0.01) isoenzyme level postoperatively: 45 +/- 39 U/l. Two patients had the ECG changes of definite myocardial infarction after valve replacement and they also showed high CK-MB values, while the other patients with high enzyme level had no ECG signs suggesting acute infarction. CK-MB values correlated with the aortic cross-clamping time (r = 0.39, p less than 0.001) and weakly with the precordial ECG voltage of SV1 + RV5 (r = 0.25, p less than 0.01). While these findings may reflect the sensitivity of a thick myocardial wall to ischaemia during surgery, the postoperative recovery was not related to the serum CK-MB level.     

Chromatographic and electrophoretic separation of creatine kinase isoenzymes compared.

We compared two techniques for separating and evaluating serum creatine kinase isoenzymes--fluorometric agarose electrophoresis and Sephadex chromatography--in 50 patients, 25 of whom had confirmed acute myocardial infarction. In every case isoenzyme MB (heart isoenzyme) was detected with equal sensitivity by either procedure. Evidently, only the presence or absence of MB is clinically significant; none of the 25 patients without infarction had detectable MB activity in their serum. Columns connected to a continuous-flow sample line for analyses of the eluting stream without further modification produced satisfactory results.     

Changes in the ratio of lactate dehydrogenase isoenzymes 1 and 2 during the first day after acute myocardial infarction

It is known that the ratio of isoenzyme 1 to total lactate dehydrogenase (LD, EC 1.1.1.27) in serum is increased in all patients with acute myocardial infarction within 24 h of the infarct. We now show that the LD-1/LD-2 ratio for serum more promptly indicates acute myocardial infarction, being for most patients equivalent to measurement of creatine kinase (EC 2.7.3.2) isoenzyme 2 (CK-2, CK-MB) in serum. Of 128 patients with a confirmed diagnosis of myocardial infarction, 66 had normal values for all "cardiac" enzymes at the time of admission, but greater than 75% of them showed a parallel increase in values for CK-2 and the LD-1/LD-2 ratio. Of the 26 patients who had one or more abnormal values for cardiac enzymes on admission, 95% showed a parallel increase in CK-2 and the LD-1/LD-2 ratio, the median time for the beginning of these changes being 9 h from the onset of chest pain. The remaining 36 patients were excluded from the study because CK-2 decreased after admission or because the time of onset of chest pain was uncertain.     

Changes in mass and catalytic activity concentrations of aspartate aminotransferase isoenzymes in serum after a myocardial infarction

We used an RIA and inhibition of enzyme activity to monitor the changes in mass and catalytic concentrations of the aspartate aminotransferase (EC 2.6.1.1;AST) isoenzymes in serum after myocardial infarction. Cytosolic (c-AST) and mitochondrial (m-AST) forms of AST were present in sera from all 38 of our patients. Although the immunological and catalytic concentrations of both isoenzymes correlated well with the size of the infarct, c-AST gave a better measure than did m-AST. About 20% of the total enzyme activity at peak activity was from the mitochondrial isoenzyme. Both isoenzyme activities peak at very nearly the same time, but m-AST has the longer half-life. Immunological evidence of the mitochondrial isoenzyme can be detected in serum for at least eight days after the infarct. The presence of left ventricular failure produces greater serum isoenzyme activities than in those without failure.     

Evaluation of a commercial immunoenzymometric assay kit for creatine kinase MB isoenzyme determination using monoclonal antibodies

A simultaneous two-site immunoenzymometric assay for creatine kinase MB determination (Hybritech Tandem-E CK-MB) using monoclonal antibodies was evaluated and compared with cellulose acetate electrophoresis using fluorometric scanning densitometry. The assay has satisfactory precision (between-day analysis gives a coefficient of variation between 2.1 and 9.4%) and is not susceptible to interference by concentrations of creatine kinase MM up to 5000 micrograms/l (3400 U/l) and creatine kinase BB up to 1000 micrograms/l (1085 U/l). The upper limit of MB isoenzyme concentration in 250 apparently healthy people was 5.5 micrograms/l. Comparison between the immunoenzymometric assay (y) and electrophoresis (x) yielded the following linear regression equation: y = 0.37x + 1.9, with a correlation coefficient of 0.828. The characteristics of the temporal kinetics of MB isoenzyme, calculated by two methods, in 49 patients with acute myocardial infarction, were nearly identical in terms of the rate of creatine kinase MB release and the time at which the peak value is obtained, but not in terms of the rate of elimination of the isoenzyme. The fractional disappearance rate of MB isoenzyme from the circulation was significantly higher if calculated with Tandem-E results rather than with electrophoresis results (-0.035 vs -0.028, p less than 0.001). Whereas in the first day after infarction immunoenzymometric assay and electrophoresis had the same clinical sensitivity for identifying patients with acute myocardial infarction, in specimens collected more than 24 hours after the onset of the chest pain, the clinical sensitivity of the immunoenzymometric method was lower. Our results show that it is still premature to draw definitive clinical conclusions from the immunoassay results.