Serum creatine kinase (CK) activity after M-subunit inhibition in patients with atypical CK isoenzymes--a comparison to findings in acute myocardial infarction

Electrophoretic analysis of enzyme-linked immunoglobulins and their clinical significance

The appearance of circulating enzyme-linked immunoglobulin complexes (E-Ig) is common for most enzymes used in clinical biochemical tests. The presence of E-Ig may result in altered enzyme activity in serum and interfere with the measurement of isoenzymes, and is thus of diagnostic importance. E-Ig can be identified by confirming that the binding protein is an immunoglobulin by its reaction with specific anti-human immunoglobulin antibodies. Currently, the presence of E-Ig in an individual is regarded as a benign phenomenon, not indicative of any particular disease process. However, it is becoming clear that E-IgG are closely associated with autoimmune states.

Creatine kinase and lactate dehydrogenase isoenzymes in stage D prostatic carcinoma

Serum creatine kinase (CK) and lactate dehydrogenase (LD) isoenzymes were determined electrophoretically, along with various other biochemical markers of malignancy, in 19 patients with metastatic carcinoma of the prostate. Mitochondrial CK appeared in 15 patients, the CK-BB isoenzyme in 6. As a result, CK activity not inhibited by anti-M-subunit antibodies, CK non-M, was above the reference value in altogether 17 patients. There was a cathodic shift among the LD isoenzymes, significantly more prominent with increasing total LD, and a positive correlation between elevations of CK non-M and LD-5, suggesting a relation to tumour burden for both. An LD 'flip' (LD-1 greater than LD-2) was present in 10/15 patients. The frequency of CK non-M elevations was similar to--but not quantitatively correlated with--elevations of prostatic acid phosphatase and alkaline phosphatase. Thus, changes in CK and LD patterns are frequent in patients with prostatic cancer and must be taken into consideration when acute cardiac symptoms are evaluated in such patients.

Release patterns of CK-MB and mitochondrial CK following myocardial ischaemia

Following myocardial damage as in acute myocardial infarction (AMI) or open heart surgery, the tissue damage might result in a release of mitochondrial CK (CK-MIT). The presence of this CK isoenzyme in serum may be detected after chromatographic separation of CK-activity on Sephacryl S-200. By combining chromatographic separation of CK-MB with immunologic inhibition of CK-M, both CK-MB and CK-MIT can be estimated in serum. Using this procedure changes in enzyme activities were studied in ten patients with AMI and twelve patients subjected to open heart surgery using cardioplegia. Following AMI CK-MB peaked about 24 h after onset of ischaemic symptoms. CK-MIT increased similarly and reached a plateau after 24 h where it remained during an additional 24-36 h. At peak CK-MB concentration, the corresponding CK-MIT activity was about 22% of the CK-MB activity. Following cardiac surgery there was a rapid release of CK-MB with a peak about 5 h after release of aortic cross-clamping, and with a simultaneous CK-MIT activity amounting to 19% of the CK-MB activity. In conclusion, CK-MIT is released into serum following myocardial ischaemia. Its appearance has time characteristics similar to that of other mitochondrial enzymes. The CK-B method does not specifically determine CK-B, but non-CK-M, which in cardiac ischaemia at peak serum CK-MB concentrations includes about 20% CK-MIT.

Cellulose acetate and electroendosmosis-low agarose electrophoresis: advanced methods for the separation and quantitative determination of serum creatine kinase isoenzyme levels

Two methods for the separation and demonstration of creatine kinase isoenzymes are described i.e. electrophoresis on cellulose acetate and on electroendosmosis-low agarose. The fluorescence of NADPH as an indicator for the creatine kinase bands was used in both methods. The methods proved to be specific, reliable and highly reproducible, and allow a rather large number of samples (12-18) to be analysed in one run within a relatively short time. The prominent advantage of the proposed methods over others is their extreme sensitivity. Both methods allow linear quantification of creatine kinase isoenzymes up to 700 U/l at 25 degrees C with a lower detection limit of 3 U/l, using a minute amount of sample (2 microliters). The diagnostic value of the methods was shown by their application to sera of patients with myocardial infarction or other diseases.