Creatine kinase isoenzymes in serum of patients with Reye's syndrome

Serum creatine kinase isoenzymes in patients with advanced malignant disease

Serum creatine kinase (CK) B subunit (CK-B) activity, as estimated by the enzymatic anti-M immunoinhibition method, and the CK isoenzyme pattern after agarose gel electrophoresis, were studied in 28 patients with advanced, untreated malignant disease. CK-B was above the decision limit, i.e. the discrimination limit used in the diagnosis of acute myocardial infarction (AMI), in 14 patients (50%). Electrophoresis demonstrated, besides CK-MM, an atypical, cathodically migrating CK band in 10 of these patients. This band may represent mitochondrial CK. The CK-BB isoenzyme was detected in 9 and CK-MB in 3 subjects. Histopathologic findings indicated that the occurrence of these isoenzymes was related to tumour burden and the overall severity of the disease. Survival among patients with CK-B elevation was shorter than among other patients. The present findings are relevant to the enzyme diagnosis of AMI and of potential significance for the evaluation of patients with known or suspected malignant tumours.

Multiple isoforms and an unusual cathodic isoform of creatine kinase from channel catfish (Ictalurus punctatus)

In vertebrates, the creatine kinase (CK) family consists of two cytosolic and two mitochondrial isoforms. The two cytosolic isoforms are the muscle type (M-CK) and the brain type (B-CK). Here we report multiple CK isoenzymes in the diploid channel catfish (Ictalurus punctatus) with one unusual cathodic isoform that was previously found only in pathological situations in human. The cathodic CK isoform existed only in the channel catfish stomach, ovary, and spleen, but not in any other species analyzed such as tilapia, smallmouth bass, chicken, or rat. Two genes encode the multiple forms of the channel catfish M-CK cDNAs. M-CK1 has three alleles, M-CK1.1, M-CK1.2, and M-CK1.3, while M-CK2 has just one allele as determined by analysis of 17 cDNA clones and by allele-specific PCR. M-CK1 encodes a protein of 381 amino acids and the M-CK2 cDNA encodes a protein of 380 amino acids. The two cDNAs shared an 86% identity and both have the nine diagnostic boxes for cytosolic CKs and thus are of cytosolic origin. The M-CK1 gene was isolated, sequenced, and characterized and its promoter should be useful for transgenic research for muscle-specific expression.

Mitochondrial creatine kinase in cancer patients

We have developed a quantitative immunoassisted enzyme assay to screen for creatine kinase isoenzymes BB (CK-BB) and mitochondrial (CK-m) using commercial antibodies and reagents. Presence of CK-m activity was subsequently confirmed by electrophoretic separation of samples with elevated values. A prospective clinical trial was undertaken in 117 subjects: Normal (30), cirrhosis patients (30), myocardial infarction patients (30), and untreated oncology patients with metastatic malignancy (27). In 12 patients with malignancy CK-m activities were elevated; all had adenocarcinomas. No significant activity was detected in patients with other malignancies. CK-m positive tumour patients had a significantly higher mortality rate, and in two instances death was preceded by a sudden rise in CK-m activity. We suggest CK-m is a marker of adenocarcinoma and its presence in serum signifies increased mortality.

The isoelectric focusing of creatine kinase variants: II. The heterogeneity of creatine kinase in human serum with normal and elevated catalytic concentrations

An effective and reliable method for the quantitative estimation of creatine kinase-MB, creatine kinase-MM variants and mitochondrial forms of creatine kinase in serum is presented. The high resolving power of isoelectric focusing allows the use of tetrazolium salts and meldola blue for the quantitative measurement without interfering non-specific reduction. The addition of thiol compounds to the agarose medium increases the sensitivity of the method, due to the inhibition of sulfhydryl group oxidation, and prevents enzyme degradation, which is a possible cause of an artificial heterogeneity. Depending upon the type of muscle and the degree of cell damage, we found 3-4 creatine kinase-MM sub-bands in sera with activities below 80 U/l. At elevated creatine kinase activities 3-11 creatine kinase-MM sub-bands were found. The appearance of creatine kinase-MB in serum indicates that damage has occurred to certain organs, especially the cardiac muscle. An organ with moderate or massive cell damage could release, in addition to the sarcoplasmatic creatine kinase variants, other forms with more alkaline isoelectric points (mitochondrial creatine kinase). The presence of such bands in serum of patients correlates with poor prognosis. Besides the separation of creatine kinase-MM sub-bands, creatine kinase-MB, creatine kinase-BB and of macroforms 1 and 2, the advantage of this method is the detection of mitochondrial creatine kinase forms, which in cellulose acetate electrophoresis migrate with creatine kinase-MM.

The enzymology of skeletal muscle disorders

In myopathic disorders, abnormal serum enzyme activities are seen primarily in diseases of skeletal muscle where the condition involves the muscle fibers themselves. In denervation myopathies, serum enzyme activities are usually normal. The most dramatic increases of serum enzymes, particularly creatine kinase, are found in the dystrophic diseases, particularly Duchenne dystrophy. A review is given here of the many causes of abnormal serum enzyme activities where the source of enzymes is believed to be skeletal muscle. These include the dystrophies, various types of trauma, exercise, drug- and poison-induced causes including alcohol, malignant hyperthermia, inflammatory diseases, and miscellaneous causes. Tissue and serum activities are summarized for the commonly performed serum enzymes, i.e., CK, LD, AST, and aldolase. An extensive tabular and current description of the various types of dystrophies is given along with serum CK and pyruvate kinase activities.

Abnormal electrophoretic mobility of creatine kinase isoenzyme in serum of an otherwise healthy person

We describe the abnormal electrophoretic mobility of a creatine kinase isoenzyme in the serum of an apparently healthy individual. In agarose gel electrophoresis this isoenzyme migrates more toward the cathode than does the MM isoenzyme. It is more resistant to heat and more strongly inhibited by urea than the normal MM isoenzyme. We performed gel filtration, on a Sephadex G-200 column, of the patient's serum and observed two distinct isoenzymes with different relative molecular masses; a normal isoenzyme of 80,000 daltons and another abnormal one of 240,000 daltons. We performed serum immunoelectrophoresis but did not observe any immune complex formation involving the abnormal isoenzyme.

Creatine kinase

Creatine kinase is present in significant concentrations in skeletal muscle and cardiac muscle and to a lesser extent in gastrointestinal tract and brain tissue. The enzyme has been purified from a variety of tissues and an examination of its kinetic and physical properties reveal that the enzyme consists of two subunits and can exist as three isoenzymes containing essential cysteine residues. These properties are important in understanding its stability, the assay conditions, and the techniques used to identify the different isoenzymes. The relationship between the properties and the determination of the enzyme in biological fluids will be a main thrust of the review. Creatine kinase activity in serum rises rapidly in conditions such as acute myocardial infarction and trauma to skeletal muscle. However, the interpretation of such increases is dependent upon a sound knowledge of the factors which influence both the total and isoenzyme activities. The nature of these factors will be discussed in detail.

Creatine kinase isoenzymes in acute brain injury

Brain-type creatine kinase (CK) isoenzyme (CK-BB) was detected in the serum in 13 out of 26 patients with acute brain injury (50%). The peak of CK-BB activity ranged from 5 to 188 U/liter, constituting, on average, 10.5% of the total CK activity. The highest activities were seen in patients with gunshot wounds. High CK-BB activity was associated with poor prognosis, but minimal CK-BB elevations did not have prognostic significance. Heart-type creatine kinase isoenzyme (CK-MB) was detected in the serum in 17 out of 26 patients (65%). The peak activity ranged from 5 to 115 U/liter, constituting, on average, 6.6% of total CK activity. Electrocardiogram taken from 20 patients revealed transient T-wave inversions in the precordial leads in four patients; three of them also showed serum CK-MB activity. Subendocardial hemorrhage was detected at autopsy in three of the five CK-MB-positive patients, but in none of the four CK-MB-negative cases. Present findings suggest that acute brain injury may be secondarily cause myocardial damage.

Cathodic isozyme of serum creatine kinase in a case of stomach cancer complicated by disseminated intravascular coagulation

A rare isozyme of serum creatine kinase (CK) migrating cathodic to CK-MM on electrophoresis was found in a 30-year-old male with stomach cancer complicated by disseminated intravascular coagulation leading to massive upper gastrointestinal bleeding and marked anemia. Serum CK activity rose to a maximum of 374 U/l without detectable CK-MB isoenzyme. The patient was also characterized by a marked increase in serum lactate dehydrogenase (all isozymes elevated) and by preferential leakage of mitochondrial aspartate aminotransferase and glutamate dehydrogenase, indicating the presence of extensive tissue damage involving mitochondria. Skeletal muscle mitochondria were considered the most likely source of the additional CK isozyme.

Radioimmunoassay measurement of creatine kinase BB in the serum of schizophrenic patients

Brain type creatine kinase (BB) isoenzyme was measured using a highly sensitive and specific radioimmunoassay procedure (limit of detection, 1 microgram/l of sample) in two schizophrenic populations, an acute non-medicated group consisting of 35 subjects and a chronic group of 15 subjects. Since the assay can also measure the B subunit of MB isoenzyme, patients were selected so as to exclude subjects with possible heart, kidney or other ailments which might result in an increased serum creatine kinase B subunit. Both the acute schizophrenics (3.0 +/- 0.23) mean S.E.M. and the chronic schizophrenics (2.9 +/- 0.33) had serum levels of creating kinase BB similar to those of controls (2.8 +/- 0.21) and non-cardiac patients (3.5 +/- 0.58). Patients having myocardial infarction or neurovascular surgery had elevated creatine kinase B subunit. Similar but much less sensitive quantitative results were obtained using agarose multizonal electrophoresis. Despite a recent report that human brain contains the creatine kinase MM isoenzyme, analysis of five human brains using DEAE-Sephadex-A50 for MM isoenzyme fractionation, followed by immunodiffusion analysis of concentrated eluate revealed no detectable MM isoenzyme. The results from these studies suggest that the elevated serum creatine kinase activity of schizophrenic patients is most likely not of brain origin.

Electrophoretic identification of the brain isoenzyme of creatine kinase following treatment with anti-BB antisera

A procedure is described for accurately determining the presence of true creatine kinase isoenzyme BB by fluorescent staining following electrophoresis on either cellulose acetate or agarose. Treatment of sera with anti-BB inhibiting antibody prior to electrophoresis and subsequent enzymatic staining allows clear identification of creatine kinase BB in presence of interfering artifacts. The utilization of an immunological means of identifying BB following electrophoresis avoids the pitfall of associating an artifactual BB isoenzyme with a disease state. Using this technique, presence of creatine kinase BB in patients with carcinoma, cardiac disease and renal failure has been verified.

[Creatine kinase isoenzymes: idiopathic occurrence of creatine kinase BB activities in patient serum (author's transl)]

By differentiation of creatine kinase isoenzyme activities in sera using immunological methods the published data about occurrence of creatine kinase BB activities in patients with different diseases or after surgical treatment, respectively, cannot be verified in general. With a frequency in the order of magnitude of 1 : 1000 in the serum of old patients (age 57 to 85 years with one exception), however, creatine kinase BB activities can be measured. The range of activities is 15 to 234 U/1, or 19 to 94% of total creatine kinase activities, respectively. At the present time there is no possibility to correlate this phenomenon to any specific disease. These cases are detected by abnormally high results of CK-MB activity measurements with the immunoinhibition test (range 60 to 202% of total creatine kinase activities) which lead to a repeated analysis using immunoprecipitation. The results of all CK-BB patients investigated till now are presented and discussed.

The production of creatine kinase isozyme BB in sera of a patient with prostatic carcinoma and in tumor homogenates

1. A CK(BB) fraction was observed in sera of a patient with prostatic carcinoma. The fraction accounted for 59% of the total enzyme activity. A metastatic tumor of a prostatic carcinoma was observed to contain solely the CK(BB) isozyme. An embryonal testicular carcinoma was observed to have a higher percentage of the CK(BB) fraction when compared to the adjacent tumor free testicular tissue in a third patient. These studies suggested that in certain carcinomas there are tissue isozyme modifications at the molecular level. The isozymic modification was suggested as a reversion towards an embroyonic pattern as the adult molecular form tended to disappear while the fetal form increased. This too suggests that the isozymes of CK may be a useful model in elucidating the mechanism through which this transition occurs. 2. The high percentage of CK(BB) in the sera of the patient with metastasis was discussed. The origin could not be determined, but either a primary tumor or a metastatic tumor by their enzyme modifications could account for this increased fraction in sera.

Creatine kinase BB isoenzyme levels by radioimmunoassay in patients with neurological disease

Creatine kinase BB (CK-BB) isoenzyme was measured by radioimmunoassay in serum and in cerebrospinal fluid from 61 patients with various neurological disorders. Statistically significant elevations of CK-BB isoenzyme in the serum were observed in patients with acute cerebrovascular accidents and in those with seizures and a prolonged alteration in level of consciousness. Statistically significant elevations of CK-BB isoenzyme in the cerebrospinal fluid were also found in patients who had suffered acute cerebrovascular accidents. Some patients with central nervous system infections, acute demyelinating disease, certain drug overdoses, head trauma, and complex migraine also had elevations of serum and CSF CK-BB isoenzyme. In 2 patients with elevations of CK-BB isoenzyme, the elevations in serum occurred later than those detected in the cerebrospinal fluid. If CK-BB elevations determined by radioimmunoassay can be demonstrated to be quantitatively related to the extent of brain damage, then these determinations in conjunction with experimental animal models and newer radiological techniques should allow evaluation, in an objective and precise manner, of measures designed to decrease that damage.