Posted by James
Previous experimental studies have shown that mesenteric infarction causes an elevation of serum total С К within the first 24 hours after an infarction. The three isoenzymes of С К also become elevated within that same time period. The majority of the enzyme elevation is CK-MM, with CK-MB and CK- BB being present but being substantially less than the amount of CK-MM present. Clinical evaluation of the CK tracings in the patients that had MES INF showed that these patients had elevations of serum total С К in the first 24 hours as did the patients who had major aortic reconstructions and AMI. All three groups went above the upper limit of normal (100 IU/L) for our laboratory within this time frame. Differentiation between these three groups of patients based on this measurement was not possible.
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Posted by James
Determination of the serum CK-MB in international units per liter showed that there were minimal elevations in the group of patients that had major aortic reconstruction; however, the groups that had AMI or MES INF showed marked elevations within the first three days after their clinical events (Fig 3). Maximum values for CK-MB (IU/L) were reached approximately 16 to 24 hours after the clinical events in both those groups. There were fairly marked variations in the amount of CK-MB present within these groups. The patients with necrotic bowel and those with myocardial infarctions could not be differentiated one from another based on these measurements alone on day 2 and day 3 following the onset of their clinical events.
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Posted by James
Patient groups consisted of 15 patients admitted to the coronary care unit who were diagnosed as having an acute transmural myocardial infarction confirmed by serial ECGs. There were 13 patients identified with bowel necrosis. The patients with AMI and those undergoing major aortic reconstructions all had serum samples drawn as noted. Those patients who had bowel necrosis had fewer samples drawn because patients were taken to the operating room or died early in their hospital course as a result of the bowel infarction. Six patients with bowel necrosis had isoenzyme determinations of LD and С К subsequent to their bowel infarctions. Two other patients had advanced so far into their clinical courses of severe bowel infarction that their enzymes were deemed unreliable for isoenzyme analysis. These two patients had profound hypoperfusion syndromes which promoted generalized decrease in perfusion of the entire body with resulting enzyme release from many organs. Only one patient subsequently survived a bowel infarction (Table 1).
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Posted by James
Three groups of patients were studied. The first consisted of 15 patients who were admitted to the coronary care unit with electrocardiographic evidence of acute transmural myocardial infarctions. These patients had serum samples drawn for isoenzyme analyses every eight hours starting with admission for the first 24 hours of their hospital course. Samples were then drawn daily for five days for isoenzyme analyses of both CK and LD. In the second group, 13 individuals who were to undergo elective aortobifemoral bypass grafts for either occlusive or aneurysmal disease were studied. These patients had normal preoperative ECGs and serum isoenzyme analyses. Postoperatively, serum samples were collected for isoenzyme determinations in the recovery room and twice daily for three days. Samples were subsequently collected daily for an additional five days. During the first two postoperative days, the patients were monitored in the surgical intensive care unit and serial ECGs were performed daily. The third group of patients consisted of eight individuals with suspected bowel infarction. Confirmation of mesenteric infarction was obtained at operation or at autopsy in all cases. Enzyme determinations were drawn preop- eratively and postoperatively at least twice daily until both С К and LD returned to normal. These patients also had daily electrocardiographic monitoring postoperatively to determine whether myocardial infarction had occurred. All blood samples were centrifuged for ten minutes at 3,000 rpm. Serum was extracted from each sample using standard pipettes. Serum total CK and LD were determined by automated spectrophotometry. Isoenzymes were determined using agarose gel electrophoresis. Results for each measurement were tabulated, compiled and graphed. Perceived differences were evaluated by the Wilcoxon rank-sum test to determine whether they were significant between groups. All values reported are values from the normal distribution reflecting an analysis of a one-sided test.
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Posted by James
Previous experimental work from our laboratory and some clinical reports suggest that peripheral serum С К becomes elevated with acute bowel infarction. The CK-MM is the dominant isoenzyme of the elevation, but CK-MB rises early and stays elevated, particularly in experimental animals with lethal injuries. Serum CK-BB also rises early, but decreases within 24 hours of the infarction. Monitoring of serum LD in acute experimental bowel infarction has shown that total serum LD rises only slightly with LD3 becoming the dominant isoenzyme in some instances. Reports from our institution and other centers suggest that similar changes occur in patients with bowel necrosis. The following prospective study was conducted to test whether the changes in these serum enzyme systems seen in acute bowel infarction could be differentiated from those seen in AMI and from changes which occur in patients who have undergone uncomplicated AAS. Read the rest of this entry »
Posted by James
In the study they demonstrated that total CPK enzyme levels were elevated in all three groups but CPK-MB isoenzymes were elevated only in the myocardial infarction and the bowel infarction groups. There was no difference in either percent CPK-MB or in total international units of CPK-MB between these two groups of patients. Fortunately, the two groups could be distinguished by examining LDH isoenzymes. The LDH-l/LDH-2 ratio was reversed in the myocardial infarction group and remained normal in the bowel infarction group, allowing a sensitive method for differentiation. Lactate dehydrogenase did not rise significantly in the control vascular surgery group. In addition CPK-BB fractions were mildly elevated in the bowel infarction group of patients but in neither of the other groups.
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Posted by James
An Evaluation of Cardiac Enzymes
Tn 1954, LaDue et al first noted rises in serum glutamic oxaloacetic transaminase (SGOT) enzyme levels following myocardial infarction. This important observation led to the evaluation of this and other serum enzyme systems as specific and sensitive indicators of myocardial infarction. Elevation of serum creatine phosphokinase (CPK) appeared to be a more sensitive conventional serum enzyme criterion for acute myocardial infarction, but false-positive results occurred frequently. In 1934, Lohman first described CPK which is found in high concentration in striated muscle, cardiac muscle, and brain tissue. Other conventional enzymes have also been used as markers for myocardial infarction, including lactate dehydrogenase (LDH) and hydroxybutyrate dehydrogenase.
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