Separation of tissue and serum creatine kinase isoenzymes on polyacrylamide gel slabs

Enzyme activities in serum after extensive exercise, with special reference to creatine kinase MB

It is well documented that elevations of serum enzymes used as criteria in establishing the diagnosis of acute myocardial infarction (AMI) often show a pattern of AMI after physical exercise without other clinical signs of myocardial damage. Since a clinical condition resembling AMI sometimes appears after strenuous physical exercise, this study was designed to show if the new, almost heart-specific, isoenzyme creatine kinase MB (CK-MB) would solve the diagnostic problems. Ten well trained volunteers took part in a 26 km jogging race. None of them had any cardiovascular symptoms, but the 'old' cardiac enzymes rose in some of them above the discriminatory levels, whereas CK-MB was below these levels in all cases. It is concluded that CK-MB determination is a valuable diagnostic tool, also in patients who have recently exercised extensively.

Oxidative stress alters creatine kinase system in serum and brain regions of polychlorinated biphenyl (Aroclor 1254)-exposed rats: protective role of melatonin

Polychlorinated biphenyls are one of the environmental toxicants and neurotoxic compounds which induce the production of free radicals. Creatine kinase plays a key role in energy metabolism of nervous tissue and might be one of the targets for reactive oxygen species. Melatonin, an indoleamine, plays an important role in neurodegenerative diseases as an antioxidant and neuroprotector. The objective of the present study was to investigate the protective role of melatonin on polychlorinated biphenyl (Aroclor 1254)-induced oxidative stress and the changes in creatine kinase activity in brain regions of adult rats. Group I: rats were intraperitoneally (i.p.) administered with corn oil (vehicle) for 30 days. Group II: rats injected i.p. with Aroclor 1254 at 2 mg/kg body weight (bw)/day for 30 days. Groups III and IV: rats i.p. received melatonin (5 or 10 mg/kg bw/day) simultaneously with Aroclor 1254 for 30 days. After 30 days, rats were killed and the brain regions were dissected to cerebral cortex, cerebellum and hippocampus. Lipid peroxidation, hydroxyl radical and hydrogen peroxide (H2O2) levels were determined. The activity of creatine kinase was assayed in serum and brain regions, and its isoenzymes in serum were separated electrophoretically. Activity of creatine kinase was decreased while an increase in H2O2, hydroxyl radical and lipid peroxidation was observed in brain regions of polychlorinated biphenyl-treated rats. Also polychlorinated biphenyl exposure showed a significant increase in serum creatine kinase level and its isoforms such as BB-creatine kinase, MB-creatine kinase, and MM-creatine kinase. Administration of melatonin prevented these alterations induced by polychlorinated biphenyl by its free radical scavenging mechanism. Thus, polychlorinated biphenyl alters creatine kinase activity by inducing oxidative stress in brain regions, which can be protected by melatonin.

Muscle damage induced by experimental hypoglycemia

To determine organ damage due to hypoglycemia, we studied the effects of insulin dose and hypoglycemia duration on serum enzyme activity in rabbits. Thirty rabbits were randomly divided into five groups according to hypoglycemia duration and insulin dose: A2, hypoglycemia for 30 minutes with 2 U/kg insulin; A10, hypoglycemia for 30 minutes with 10 U/kg insulin; B2, hypoglycemia for 60 minutes with 2 U/kg insulin; B10, hypoglycemia for 60 minutes with 10 U/kg insulin; and C, no hypoglycemia with 10 U/kg insulin and 50% glucose. Insulin-induced hypoglycemia was reversed by intravenous injection of glucose. Alterations in serum enzyme activity and creatine kinase (CK) isoenzyme distribution were determined before and after insulin injection. Serum CK activity increased significantly in all hypoglycemic groups compared with preinjection values, and tended to remain high for 24 hours in both groups A10 and B10. Serum activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) increased only in group B10. In addition, the level of band 4 of serum CK isoenzymes, which exists predominantly in skeletal muscle and myocardium, increased significantly in group B10. These results suggest that the increase in both serum enzyme and CK band 4 isoenzyme activities during hypoglycemia is primarily due to damage in muscle rather than liver, and that the hypoglycemia duration and insulin dosage may influence the extent of organ damage.

Phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and creatine kinase activity and isoenzymes in human brain tumours

The distribution of phosphoglycerate mutase (EC 5.4.2.1, PGM), 2,3-bisphosphoglycerate phosphatase (EC 3.1.3.13, BPGP) and creatine kinase (EC 2.7.3.2, CK) activity and isoenzymes in various regions of adult human brain and in brain tumours (astrocytomas, anaplastic astrocytomas, glioblastomas and meningiomas) has been determined using electrophoresis. PGM and cytosolic CK exist in mammalian tissues as three isoenzymes that result from the homodimeric and heterodimeric combinations of two subunits [types M (muscle) and B (brain)] coded by separated genes. In addition, a dimeric form and an octameric form of mitochondrial CK exist in mammals. Type BB-PGM was the major PGM isoenzyme found in normal brain, although type MB-PGM and type MM-PGM were also detected. All brain tumours possessed lower PGM activity than normal brain, and meningiomas showed higher BPGP activity. In astrocytic tumours, the proportion of type MB- and type MM-PGM decreased, and in meningiomas these isoenzymes were not detected. Type BB-CK and mitochondrial CK were the only CK isoenzymes detected in normal brain. Astrocytomas possessed lower CK activity than anaplastic astrocytomas and glioblastomas and, in addition, tended to possess lower CK content than normal brain. No qualitative changes of the normal CK isoenzyme pattern were observed in the tumours.

Creatine kinase activity and isoenzymes in lung, colon and liver carcinomas

We have compared the levels of creatine kinase (CK) activity and the distribution of CK isoenzymes determined by agarose gel electrophoresis in normal colon, liver and lung tissues, and in colon, liver and lung adenocarcinomas, lung squamous cell carcinomas and lung carcinoids. Colon and lung adenocarcinomas, and squamous cell carcinomas presented lower CK activity than the normal tissues and no differences were found between hepatocarcinoma and normal liver tissue. In contrast, lung carcinoids had higher CK activity than normal lung tissue. Type BB-CK was the predominant isoenzyme in normal lung, colon and liver tissues. Type MM isoenzyme was detected in normal lung and type MB-CK was found in normal colon. In most lung tumours the CK isoenzyme electrophoretic pattern did not change. However, no type BB-CK was detected in some hepatocarcinomas, type MM-CK decreased in lung carcinoids and type MB isoenzyme was not observed in colon adenocarcinomas. It is concluded that in most tumours there is a decrease in the expression of type B- and type M-CK subunits, whereas in lung carcinoid the expression of type B-CK activity increases. Thus, the increase in type BB-CK observed in the serum of patients with lung and colon adenocarcinomas is probably due mainly to enhanced enzyme release as a result of tumour cell necrosis.

Expression of the mitochondrial creatine kinase genes

Mitochondrial Creatine Kinase (MtCK) is responsible for the transfer of high energy phosphate from mitochondria to the cytosolic carrier, creatine, and exists in mammals as two isoenzymes encoded by separate genes. In rats and humans, sarcomere-specific MtCK (sMtCK) is expressed only in skeletal and heart muscle, and has 87% nucleotide identity across the 1257 bp coding region. The ubiquitous isoenzyme of MtCK (uMtCK) is expressed in many tissues with highest levels in brain, gut, and kidney, and has 92% nucleotide identity between the 1254 bp coding regions of rat and human. Both genes are highly regulated developmentally in a tissue-specific manner. There is virtually no expression of sMtCK mRNA prior to birth. Unlike cytosolic muscle CK (MCK) and brain CK (BCK), there is no developmental isoenzyme switch between the MtCKs. Cell culture models representing the tissue-specific expression of either sMtCK or uMtCK are available, but there are no adequate developmental models to examine their regulation. Several animal models are available to examine the coordinate regulation of the CK gene family and include 1) Cardiac Stress by coarctation (sMtCK, BCK, and MCK), 2) Uterus and placenta during pregnancy (uMtCK and BCK), and 3) Diabetes and mitochondrial myopathy (sMtCK, BCK, and MCK). We report the details of these findings, and discuss the coordinate regulation of the genes necessary for high-energy transduction.

Specificity of an immunochemical reagent for quantifying the isoforms of creatine kinase-MB

Fractionation of the creatine kinase-MB isoforms is promising for use in diagnosing acute myocardial infarction and for monitoring myocardial perfusion status after thrombolytic therapy. An immunochemical reagent intended for use in fractionating the MB1 and MB2 isoforms of creatine kinase-MB was examined before and after immunoextraction, qualitatively by visually examining electrophoresis separation of various MB1 and MB2 mixtures, and quantitatively by comparing the observed and predicted enzymatic activity of various MB1 and MB2 mixtures. Qualitatively the reagent showed greater reactivity for MB1 than for MB2, as demonstrated by a marked decrease in the MB1 electrophoretic region following immunoextraction. Quantitatively, the reagent consistently eliminated about 75% of MB1 activity; however, the assay also eliminated about 40% of MB2 activity from isoform mixtures. Although the performance of the immunochemical reagent was not ideal, the greater reactivity for MB1 may have clinical use.

Electrophoresis of serum isoenzymes and proteins following acute myocardial infarction

The clinical significance of the serum enzymes creatine kinase (CK, EC 2.7.3.2), lactate dehydrogenase (LD, EC 1.1.1.27) and aspartate aminotransferase (EC 2.6.1.1), and the isoenzymes CK 1-3 and LD 1-5, in acute myocardial infarction (AMI) is reviewed. Particular attention is given to electrophoretic analysis of the isoenzymes (and the CK isoforms/subforms) following AMI and thrombolytic therapy. Other protein markers for the monitoring of AMI, including myoglobin and muscle contractile proteins, are also discussed and the potential for the detection of new marker proteins using high-resolution two-dimensional electrophoretic methods is demonstrated. Whilst emphasis is placed upon electrophoretic methods the value of complementary immunoassays is acknowledged in order to maintain a balanced perspective.

Serum release of the creatine kinase tissue-specific isoforms MM3 and MB2 is simultaneous during myocardial reperfusion

The release sequence of the creatine kinase MM and MB tissue-specific subforms after myocardial reperfusion was elucidated by computer-fitting serial enzyme data from 6 humans in whom coronary flow in the infarct-related artery was angiographically documented as initially zero, opening to normal after angioplasty. The model equation used demonstrated acceptable performance according to standard criteria including visual examination and statistical parameters. The model successfully described the sequential conversion of the MM3 and MB2 tissue isoforms to their respective MM2 and MM1, and MB1 isoforms. Release of MM3 and MB2 was simultaneous, differing in calculated release times by 0.2 to 10%, median 3%. Since MB2 release is not retarded after myocardial reperfusion compared to the more clinically established CK-MM3 isoform, assays for sensitive and rapid measurement of MB2 should be the focus for the non-invasive assessment of myocardial reperfusion due to its higher cardiospecificity.

Heterogeneity of serum creatine kinase isoenzyme-MM in acute myocardial infarction

Isoelectric focusing of serum creatine kinase (CK;EC 2.7.3.2) reveals up to 14 CK-MM subbands following acute myocardial infarction (AMI). The "normal" subbands 1 (pI 6.91), 2 (pI 6.65) and 3 (pI 6.35) are faintly present in normal serum and the "abnormal" subbands c (pI 7.25), e (pI 6.85), g (pI 6.50), i (pI 6.28), j (pI 6.20) and k (pI 6.15) are prominently detected in sera with elevated CK. "Abnormal" subbands a (pI 7.55),b(pI7.35),d(pI7.05),f(pI6.72) and h(pI6.40) have only been detected in AMI. The "abnormal" subbands appear, and reach maximum intensity (together with CK-MM 1-3), 3-12 h after infarction, and become faint and anodally convert (as do CK-MM 1-3) within 36 h. Similar changes are detected by nonequilibrium pH gradient electrophoresis which combines CK-MM and CK-MB analysis. In vitro incubation of serum with 0.015 M 2-mercaptoethanol induces conversion of CK-MM 1, 2 and 3 to b and c, d and e, and f and g, respectively. Thus, the complexity of the patterns is explained by a secondary conversion of "normal" to "abnormal" subbands superimposed upon anodal conversion of CK-MM 1----3. The clinical significance of these findings is discussed.

Isolation of creatine kinase BB isoenzyme with high specific activity and adequate purity for radioimmunoassay from human placenta on preparative polyacrylamide gel electrophoresis

This report describes the procedures for isolation of creatine kinase BB isoenzyme (CK-BB) from human placenta on preparative polyacrylamide gel electrophoresis. 2.5 mg of CK-BB was purified from a 100-g portion of the human placenta, which had a mean specific activity of 957 kU/g and a mean yield of 16%. The placenta CK-BB exhibited single protein bands on several electrophoretic techniques. In addition, both of the placenta and brain CK-BB preparations were individually iodinated and the identical immunological properties of both the CK-BB preparations were confirmed in radioimmunoassay.

Serum isoforms of creatine kinase isoenzymes

The CK-2 and CK-3 isoenzymes of human serum creatine kinase (CK) can be further subdivided into five isoforms (subforms derived from the same isoenzyme). Three are derived from CK-3 and two from CK-2. The formation of these isoforms is a postsynthetic phenomenon brought about by a serum carboxypeptidase that acts on the M monomer of the enzyme. Sera from healthy subjects contain CK-3(1) as the dominant isoform with lesser amounts of CK-3(2) and CK-3(3). Following damage of muscle tissue, the serum isoform distribution changes as a result of the increased release of CK enzyme. This provides more diagnostic information concerning acute myocardial infarction and other muscle diseases than is available from routine CK isoenzyme analysis.

Creatine kinase isoenzymes

Analytical methods for and the clinical significance of ATP:creatine-N-phosphotransferase (EC 2.7.3.2, CK) isoenzymes have been described. The main assay methods for the isoenzymes are electrophoresis, ion-exchange chromatography and immunoinhibition. Electrophoresis is a time-consuming technique, but it is essential for the identification of CK isoenzymes. Ion-exchange chromatography is reliable for the determination of CK-MB and useful for the isolation and purification of CK isoenzymes. The disadvantages of this method are overlapping of isoenzymes with neighbouring fractions and the inevitable dilution of enzyme activity by the elution buffer. Immunoinhibition is a rapid, sensitive, specific and quantitative technique. However, mitochondrial CK and CK-immunoglobulin complex remain after the inhibition of the M subunit with the antibodies. Thus, when assessing the experimental results, it is necessary to be certain that a false positive for CK-MB has not been obtained. Since each technique has both merits and demerits, the technique most suited to the particular laboratory should be selected.

The BB-isoenzyme is a major component of creatine kinase in skin blister fluid

We measured levels of creatine kinase and its three isoenzymes in serum and blister fluid from 16 healthy volunteers. The BB-isoenzyme was found to be the predominant form in blister fluid while only the MM isoenzyme was found in serum. The levels of BB-isoenzyme in blister fluid decreased as the blisters aged. The source of BB-isoenzyme in blister fluid is most probably the damaged epidermis.

Evaluation of the usefulness of enzymatic diagnosis of myocardial infarction in patients with acute arterial occlusion of the lower extremities

The serum activities of aspartate aminotransferase, lactate dehydrogenase, creatine kinase and estimated creatine kinase isoenzyme MB (CK-B) were investigated in 12 patients before and after revascularization of ischaemic lower extremities. All patients suffered from sudden lower limb arterial occlusion and underwent embolectomy through a small arteriotomy in the groin. The median serum activity of all four enzymes was elevated before surgery and further increased during the first 24-48 h after revascularization. Median serum activity of aspartate aminotransferase, creatine kinase and lactate dehydrogenase were continuously elevated 7 days after the operation. A high relative CK-B activity coincided in one patient with the development of electrocardiographic evidence of acute myocardial infarction. It is concluded that any of these four enzymes should be used with caution in the diagnosis of acute myocardial infarction before, during or after operation in patients who have sustained prolonged ischaemia of the lower extremities.

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.

Diagnostic changes in plasma creatine kinase isoforms early after the onset of acute myocardial infarction

Conventional plasma isoenzyme and enzyme values usually are normal during the first few hours of acute myocardial infarction. Thus definitive diagnosis may be delayed. We have shown recently that infarction in dogs can be detected within 1 hr after coronary occlusion by analysis of relative activities of MM creatine kinase (CK) isoforms in plasma. Isoforms of MM CK evolve through posttranslational modifications in plasma of the form released from tissue (MMA) to MMB and MMC. In this study we quantified changes in isoform profiles in the first available plasma samples from patients with evolving myocardial infarction, from patients with angina, and from normal subjects. In the 26 control subjects, the ratio of MMA to MMC was 1.09 +/- 0.4 (SE) (range 0.31 to 3.1; upper limit of normal [defined as the mean plus 2 SD] 2.5). In the seven control patients with coronary artery disease, the ratio of MMA to MMC was 1.3 +/- 0.3 with a range of 0.5 to 2.5. In contrast, among the 28 patients with acute myocardial infarction, the ratio of MMA to MMC in the first available plasma sample averaged 14.6 +/- 4.5 (p less than .01 compared with both control groups). First available samples were obtained 3.9 +/- 0.4 hr after the onset of pain. In 24 of 28 patients (86%) the ratio of MMA to MMC was greater than 2.5.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparisons between CK-B and other clinical indicators of cardiac contusion following multiple trauma

The activity of creatine kinase (CK) and creatine kinase B(CK-B) was measured in 17 patients with injuries to multiple organ systems, including the chest. The patients were closely observed for clinical signs of disturbed cardiac function by means of serial ECG, continuous monitoring of cardiac rhythm, daily cardiac auscultation, serial chest roentgenography and monitoring of central hemodynamic parameters. No statistically significant difference in CK and CK-B activity was found between the group of patients with normal cardiac function and the group with disturbed cardiac function. The CK-B activity was markedly elevated, but CK-B activity relative to CK activity was normal in both groups during the first 7 days after the trauma. The authors conclude that the significance of these enzymes' serum activity, measured with the immunoinhibition method, is diagnostically doubtful not only as regards cardiac contusions, but also in other cardiopathy preceding or following major trauma.

Properties of creatine kinase-BB from canine and human brain tissues

Creatine kinase (EC 2.7.3.2) BB isoenzyme (CK-BB) was purified to homogeneity from canine and human brain tissues. The purified protein from both sources exhibits Mr of 84,700 daltons. The canine isoenzyme exhibits several properties similar to human isoenzyme with respect to reactive and total thiol groups, UV spectra, isoelectric points and reaction kinetics. While both canine and human CK-BB isoenzymes are unstable compared to other CK isoenzymes, canine CK-BB is even less stable than the human enzyme, losing most of its activity within 20 h at 4 degrees C at pH 5.0. Addition of 2-mercaptoethanol does not prevent rapid loss of the enzyme activity. Increasing the pH to 9.0, however, increases the stability of both CK-BB isoenzymes. Agarose electrophoresis demonstrated the presence of MM as well as BB isoenzyme in various parts of brain tissues. BB was present at an activity of 90.8-93.3 U/mg and MM at 6.7-9.2 U/mg.

Investigation of the heterogeneity of the MM isozyme of creatine kinase

MM creatine kinase (MM CK) from human skeletal muscle was resolved into 21 subspecies by isoelectric focusing. Rabbit and bovine MM CK's were also shown to have patterns of 21 bands. These results are compatible with the presence of six different M subunit forms in skeletal muscle, which by random association into dimers, could produce 21 different subspecies of creatine kinase. Two-dimensional isoelectric focusing of human MM CK yielded a diagonal pattern, indicating that the various enzyme subspecies were not induced by ampholyte-protein interaction. Heat inactivated serum appeared to stabilize various CK subspecies and also produced one further anodally migrating MM CK form. Fresh serum had combined inhibitory and stabilizing effects on the MM CK subforms, and allowed for the identification of four anodally migrating CK subspecies not present in tissue extract. These findings are of critical importance because of the widespread use of CK isoenzymes in serum for diagnostic purposes.

CK isoenzymes and transaminases after coronary cardiography, cardiac surgery and non-cardiac thoracotomy

The diagnosis of a heart infarct in the early postoperative period is often difficult. In the present study, the levels of serum CK, its isoenzymes (MM, MB and BB), aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were followed up after coronary arteriography (12 patients), cardiac surgery (23 patients) and non-cardiac thoracotomy (28 patients). Elevation of MB was not detected after coronary arteriography, except in two patients, who had had even before the examination a mildly positive MB finding and electrocardiographic changes indicative of subendocardial infarction. After cardiac surgery the MB findings were positive in all but two patients, who had undergone aortic valve surgery. However, the average MB level was lower than in the 10 heart infarct patients who served as controls. After non-cardiac thoracotomy, six patients had a positive serum MB, but the value of MB was quite low as compared with values after cardiac surgery and nearly insignificant in terms of heart infarct diagnosis.

Characterization of an atypical creatine kinase from human heart tissue, with properties similar to those of mitochondrial creatine kinase

The 600 X g particulate fraction, obtained from the homogenates of human heart muscle, contained large quantities of an atypical creatine kinase (CK-Z). Creatine kinase Z migrated cathodically relative to CK-MM on agarose gel electrophoresis, and was not inhibited by antibodies directed against human CK-MM and CK-BB. Creatine kinase Z had an apparent Km for Mg-ADP and creatine phosphate of 0.04 mmol/l and 1.3 mmol/l, respectively. This enzyme existed in two molecular forms; one form of molecular weight 33 000-38 000 in the presence of a buffer containing Tris-HCl (0.05 mol/l), EDTA (0.001 mol/l), and 2-mercaptoethanol (0.010 mol/l), pH 8.0; and another form having a molecular weight of 62 000-68 000 in the presence of a buffer containing sodium phosphate (0.020 mol/l) and EDTA (0.001 mol/l), pH 8.0. Creatine kinase Z had biochemical properties which were different from those of the other soluble creatine kinase isoenzymes (MM, MB and BB), but similar to those reported for mitochondrial creatine kinases isolated from other animal tissues.

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 in seminal plasma of infertile men: activity and isoenzymes

Creatine kinase (CK) activity was determined in the seminal plasma of 169 men divided in a) 11 groups according to etiological diagnosis of infertility and b) 2 groups on the basis of the normal or abnormal spermiogram. Electrophoretic separation of CK isoenzymes on agarose gel was also performed. We found that: 1) in seminal plasma enzyme activity is 4.2 times higher than the upper limit in normal serum, 2) CK activity in seminal plasma is exclusively due to the isoenzyme BB (CK1). 3) there is a statistically significant difference of the enzyme levels between men with normal spermiogram and oligo-asthenozoo-spermics, yet with wide overlapping of the individual values, 4) there is no correlation between CK activity and the variables of the spermiogram, as well as between enzyme activity and fructose or acid phosphatase in seminal plasma.

Seminal plasma creatine kinase activity in fertility studies

Creatine kinase activity was measured in the seminal fluid of 70 males undergoing fertility studies. The average value obtained at 30 degrees C was 333 +/- 197 IU/l (average +/- SD). There was no evidence of a significant correlation between creatine kinase enzymatic activity and density, active lineal motility, or number of normal motile spermatozoa; nor was there any correlation seen between creatine kinase activity and concentration of citric acid, (indicator of prostatic function) or fructose, (indicator of seminal vesicle function). Nonetheless, in two cases of excretory azoospermia, very high values of creatine kinase (2510 and 1280 IU/l) and citric acid levels (4000 and 3000 mg/dl) were observed. These would indicate that the origin of creatine kinase is fundamentally prostatic, in contradiction to previous studies by other authors. In this sense, creatine kinase would be a parameter of prostatic function in studies of male fertility. In two cases of secretory azoospermia due to cryptorchidism and in several very severe oligoasthenozoospermias, low creatine kinase levels were seen, while fructose and citric acid levels were normal. This would give relative value to creatine kinase as an indicator of spermatogenesis.

Effects of oestrogens on erythrocyte enzyme efflux in normal men and women

In the normal female range for serum creatine kinase, the large diminutions associated with the reproductive period and with pregnancy are apparently related to oestrogen production. Specimens of heparinised blood from healthy men and women were stressed by chilling, and showed the predictably large efflux of erythrocyte aldolase and lactate dehydrogenase into plasma. In aliquots of the same specimens simultaneously stressed in the same way, previous substitution of the natural plasma with pregnant plasma rich in oestrogens gave a marked significant reduction in the efflux of both enzymes in women, but not in men. The significance of these findings is discussed.

Unusually high creatine kinase BB isoenzyme and study of lactate dehydrogenase pattern in metastatic adenocarcinoma of the prostate

We report a case of metastatic adenocarcinoma of the prostate with widespread bony and hepatic involvement having extremely high BB isoenzyme of creatine kinase in serum (2405 U/liter). The serum LD5/LD1 ratio is greater than one, with total LD activity more than twenty-five fold the normal value. The homogenate of prostate gland of the patient shows an extra band with electrophoretic mobility between MM and MB isoenzymes of creatine kinase and highly elevated LD5 fraction compared to LD1 (33% vs. 9%), a remarkable LD isoenzyme pattern of malignant prostate tissue.

The presence of creatine kinase BB isoenzyme in patients with prostatic cancer

Creatine kinase BB isoenzyme (CK-BB) was detected in abnormal amounts in serum samples from 11 of 46 patients with Stage D carcinoma of the prostate by electrophoresis. Thirteen of 46 Stage D patients had elevated acid phosphatase values and 10 of these 13 had elevated CK-BB. CK-BB elevations were less frequent in earlier stages of prostatic cancer; Stage C: 0 of 35, Stage B: 1 of 26, Stage A: 0 of 3 and none in a group of 35 with BPH, prostatitis and bladder cancer. Results of CK-BB by a specific radioimmunoassay correlated well with those obtained by electrophoresis in most cases. Several patients were followed over time and data on CK-BB is presented for this interval. The origin of the CK-BB is still unclear. The BB isoenzyme predominates in prostatic tissue and CK-BB is the fetal form of the enzyme in human muscle and myocardium. The increase in serum CK-BB may be related to increased release of the isoenzyme, either from the prostate itself or from a metastatic lesion, or may represent a release of the fetal form of the enzyme from dedifferentiated tumor tissue.

Creatine phosphokinase isoenzymes and the diagnosis of myocardial infarction

Although CPK-MB determinations are useful adjuncts in diagnosing myocardial infarction (MI), the values are frequently elevated in circumstances other than infarction and almost certainly remain normal in some patients who have sustained myocardial necrosis. Elevations in patients with trauma, sustained tachyarrhythmias, and unstable angina can be particularly confusing. As there is still no adequate diagnostic standard for MI, in many cases the clinician can only make a judgment as to the probability of infarction.

Creatine kinase isoenzyme MB assay by electrophoresis

A method for determination of the creatine kinase isoenzyme MB (CK-MB) is reported: separation of the isoenzymes was done by electrophoresis and the activity of the isoenzyme bands quantitated by scanning fluorometry. Total CK activity was used for calculation of CK-MB level. The precision of the method was satisfactory: coefficient of variation 5-10%. Its accuracy good: CK-MB was consistently found in high concentrations in tissue extracts of myocardium, but was virtually absent in skeletal muscle and could not be demonstrated in serum from patients with skeletal muscle damage. The sensitivity of the method fitted its clinical use: CK-MB was undetectable (less than 5 U/l) in normal sera, below 30 U/l in seventy-six out of seventy-seven patients in whom the diagnosis of acute myocardial infarction (AMI) was disproved, and above 30 U/l in all seventy-two patients with AMI according to WHO criteria. The CK-MB concentration in serum rises to a maximum about 20 h after onset of clinical symptoms of AMI and reaches baseline levels 20-30 h later. The electrophoretic CK-MB method is easy, fast and reliable and is considered as an important diagnostic test for AMI.

Pitfalls to avoid when comparing CK-MB fractionation by antibody inhibition reaction and DEAE-Sephadex column chromatography

1. We compare the Roche ion-exchange column chromatography and the Merck antibody inhibition reaction for CK-MB fractionation in 51 sera. Measurements of total CK and CK-MB activities must be done under the same conditions for each method in order to correlate the results. 2. A decisional value must be used for the interpretation of CK-MB results. We have used 10% for the inhibition assay and 3% for the chromatography procedure. The use of a percentage should be preferred to use of CK-MB activity alone. 3. When the % of CK-MB was established for the 51 patients only 4 results disagreed between the two methods. Three of these could be explained by a lack of sensitivity of the column chromatography procedure. 4. The antibody assay produces reliable results. Since CK-BB and CK-MB are simultaneously measured, the method is therefore prone to interference by CK-BB when present in serum. The assay is greatly affected by the presence of adenylate kinase in serum. It is not necessary to run a serum blank with this procedure when the serum in pre-incubated for 7 minutes with the reagents. 5. The Roche method also produces reliable results but offers less sensitivity when total CK remains in the normal range. The procedure is much less affected by the presence of adenylate kinase.

Sensitivity and specificity of MB creatine kinase activity determined with column chromatography

Several analytic techniques are used to estimate the activity of creatine kinase (CK) isoenzymes. These techniques are undergoing continual refinement because the MB CK molecule appears to be nearly cardiospecific. An improved column chromatographic assay is presented with a lower limit of analytic detection of 0.8 mlU/ml. The assay was applied to normal subjects and to patients with myocardial infarction and with complex disease states. Results of the column chromatography were compared with those of agarose and cellulose acetate electrophoresis. There was MB CK activity in all normal sera (no. = 19, mean +/- standard deviation = 2.4 +/- 7). After acute myocardial infarction the MB CK activity increased by 650 percent (no. = 86, mean +/- standard error of the mean = 158.2 +/- 12.6 mlU/ml). The sensitivity for myocardial infarction was 100 percent. The specificity, evaluated in multiple clinical states, approached 100 percent. The column assay was compared with both agarose and cellulose acetate electrophoresis, and poor correlations with these semiquantitative systems were demonstrated. Finally, peak MB CK activity was closely correlated with kinetic analyses used to estimate infarct size (r = 0.94). Thus, column chromatography is a sensitive and specific method of estimating MB creatine kinase activity and is more precise than current electrophoretic methods.

Creatine kinase MB isoenzyme in the evaluation of myocardial infarction

The measurement of serum CK-MB isoenzyme is a very sensitive and specific indication of myocardial injury since only myocardium has substantial amounts of CK-MB. Serum CK-MB levels are most helpful clinically when the total creatine kinase is nonspecifically elevated, as with intramuscular injections, cardiac catheterization, stroke, noncardiac surgery and electric cardioversion. Elevations of serum CK-MB occurring in Duchenne's muscular dystrophy and other neuromuscular disorders may be due to the presence of abnormal regenerative skeletal muscle fibers, which are known to contain large amounts of CK-MB isoenzyme. These examples emphasize that under normal, nonregenerative conditions, elevations of serum CK-MB are rare in the absence of myocardial injury.

Creatine kinase forms in human skeletal and cardiac muscle

The creatine kinase (CK) activity in human skeletal and cardiac muscle submitted to QAE-Sephadex chromatography was found to distribute into three peaks (m and h I, II, III fractions). Characterization according to electrophoretic behaviour, approximate molecular weight, thermal stability and immunological properties unambiguously demonstrated the coincidence of fractions I and III with reference MM-CK and MB-CK isoenzymes, while both cardiac and muscular forms II proved to escape any assignment within the dimeric (M, B) model. A higher molecular weight than for reference CK and the absence of interaction with BB-antiserum resulted for both forms II, which on the contrary were found to diverge as for reactivity to MM-antiserum and stability characteristics. Quantitation of the CK forms, attempted on a limited number of samples, confirmed the expected relative levels of MM-CK and BB-CK and gave evidence for the presence of hII- or mII-CK amounting up to 30% of the total activity in cardiac and skeletal muscle, respectively. The results of the study both confirm a complexity greater than supposed for the CK system and point to the inadequacy of several of the commonly used analytical approaches to derive correct information.

Radioimmunoassay of creatine kinase: studies on the skeletal muscle and cardiac muscle enzyme (MM and MB isoenzymes) in serum and neuromuscular tissues

A radioimmunoassay, specific for the isoenzymes of creatine kinase containing the M subunit of the enzyme (MM and MB creatine kinase), was employed to determine total creatine kinase concentrations in serum and neuromuscular tissues independently of the state of activity of the enzyme. This technique provides a method for the detection of inactive enzyme, which could be produced by inhibitors of the enzyme or by mutations involving the active site of the enzyme. A series of experiments were carried out to compare the amount of creatine kinase in various samples as assessed by normal enzyme kinetic procedures and by radioimmunoassay. The two techniques yielded equivalent results in all situations tested. Samples included serum from normal subjects and subjects with genetic and acquired diseases of muscle and also extracts from skeletal and cardiac muscle. Small quantities of immunoreactive enzyme were found in nervous tissue and assessed in terms of the incidence of the M subunit.

[Isoenzymes of creatine kinase: distribution in the skeletal muscle and in sera of patients with muscular diseases or damages (author's transl)]

In skeletal muscle isoenzymes of CK were determined by immunprecipitation and chromatography. The activity of CK-MB was between 17 and 47 U/g muscle, corresponding to a quota between 2,1 and 4,2% of the total activity. In sera of patients with muscular dystrophy, polymyositis, hypothyroidism, after arterial embolism, epilepsy, hyperventilation, operations and polytrauma with and without injury to the thorax isoenzymes were measure by immune precipitation- and immune inhibition-test. The percentage of CK-MB in all sera was less than 6% of the total CK-activity (range: 0 to 6%). Only patients in the first day after neurosurgical operations showed a quota till to 6.5% CK-MB. In serum of patients after polytrauma without injury to the thorax the percentage of CK-MB ranged from 0-5.7% while after polytrauma with injury to the thorax and a reasonable suspicion of a damage to the myocardium this quota was between 5.1 and 23.6% of the total activity. CK-BB activity was not detectable in any cases. Therefore a disease or damage of the skeletal muscle is more probable, if the percentage of CK-MB in less than 6%, because in sera of patients with myocardial infarction in the first 48 h after beginning of the symptoms this quota of CK-MB in the most cases in more than 6%.

[Studies of activity kinetic of isoenzyme CK-MB in serum after myocardial infarction (author's transl)]

We investigated the activity kinetics of CK-total and CK-MB in 83 patients with proven myocardial infarctions. Serial serum samples were taken at intervals of 2--6 h. The activity of isoenzym CK-MB was determined by means of the immunological inhibition method. CK-MB activity was determined in all patients. The mean peak activity of CK-MB was 65 U/l (range: 9-241 U/l). At the time of peak CK-MB activity the mean percentage CK-MB activity was 13.2% (range: 3.4--21.7%). The CK-MB activity reached its peak at 17.4 h (range: 3.0--32.5 h) after the onset of retrosternal pain. This is 1.4 h after peak CK-total activity. The mean disappearance rate constant for CK-MB (n = 31) was found to be 9.3 X 10(-4) U/min with a large individual variation. This value corresponds to a half life of 12.5 h (CK-total: 15.5 h). The determination of CK-MB activity is therefore only of diagnostic significance within 48 h of possible myocardial occurrence. Moreover, isoenzyme CK-MB is not found exclusively in myocardium. For this reason it is better to use the percentage CK-MB activity in the differential diagnosis of myocardial infarction. With 80% of the patients this value is greater than 6% within 36 h of proven myocardial infarction.