Cathodally migrating creatine kinase in sera of patients treated with theophylline, and its diagnostic implications
Delahunty, T.J.
Clinical Chemistry 29(8): 1484-1487
1983
ISSN/ISBN: 0009-9147 PMID: 6872206 Document Number: 206726
Sera from 30 patients, selected only on the basis of having serum theophylline concentrations greater than or equal to 18 mg/L, were assayed for total creatine kinase (CK), isoenzyme CK-MB, and cathodally migrating CK (mCK-2). CK-MB was measured by ion-exchange chromatography. mCK-2 was detected by electrophoresis on agarose gel, with fluorometric scanning. The mCK-2 variant was found in 37% of these 30 patients. None of the patients in the mCK-2 group had CK-MB values exceeding the cutoff value associated with myocardial infarction, so extensive cardiac ischemia was considered unlikely. A review of the patients' records supported this conclusion, and no particular association with any specific disease was found among the mCK-2 group. Investigations with use of goat anti-CK-MM and anti-theophylline indicated that neither CK-MM nor theophylline were present in the mCK-2. Results of specific radioimmunoassay for CK-B subunit were negative. The mobility of the mCK-2 peak was unresponsive to 2-mercaptoethanol, suggesting that CK of mitochondrial origin was not present. These results provide insight into the clinical relevance of mCK-2 and some information concerning its composition.