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[Usefulness of CK-MM isoforms for early stage of acute myocardial infarction using electrophoretic technique]
I Sakurabayashi1, S Morita, H Tsukada
1Department of Clinical Laboratories, Omiya Medical Center Jichi Medical School.
Insights
The MM3/MM1 ratio of creatine kinase (CK) isoforms can help diagnose myocardial infarction. This ratio remains elevated longer in heart attacks than in skeletal muscle conditions, aiding in diagnosis.
Area of Science:
- Biochemistry
- Clinical Chemistry
- Enzymology
Context:
- Creatine kinase (CK) MM isoforms are crucial biomarkers.
- Distinguishing cardiac from skeletal muscle injury is clinically significant.
- High-voltage electrophoresis allows for CK isoform analysis.
Purpose:
- To investigate the diagnostic utility of the CK-MM3/MM1 ratio in acute myocardial infarction.
- To compare the time course of CK isoform changes in myocardial infarction versus skeletal muscle disease.
Summary:
- CK-MM isoforms were analyzed in patients with acute myocardial infarction using high-voltage electrophoresis.
- The peak MM3/MM1 ratio occurred at 9.4 hours post-onset, significantly earlier than total CK or CK-MB.
- In vitro studies showed myocardial CK-MM3 conversion is slower than skeletal muscle CK-MM3, suggesting prolonged elevation in cardiac events.
Impact:
- The CK-MM3/MM1 ratio may serve as a more sensitive and prolonged indicator of myocardial infarction.
- This finding could refine diagnostic strategies for acute cardiac events.
- Understanding CK isoform kinetics aids in differentiating cardiac and non-cardiac causes of elevated CK.
Abstract:
MM isoform of CK (EC 2.7.3.2) was able to detect by high voltage electrophoresis. Sequential blood samples were collected from the patients with acute myocardial infarction and MM isoform (as MM3/MM1 ratio), CK activity and CK-MB activity were tested. Time of the maximum MM3/MM1 ratio from the onset was 9.4 hrs (average of 16 cases) whereas 15.9 hrs on CK-MB activity and 17.3 hrs on CK activity were detected. In vitro time course of CK-MM isoform from myocardial and skeletal muscle extracts was tested. MM3 band was gradually converted into MM2 and then MM1 band, but MM3 isoform from myocardium was changed less than skeletal muscle. From these results, it is suggested that abnormal MM3/MM1 ratio on myocardial infarction continues relatively longer time than that on skeletal muscle disease.