Normal CK Research Articles

The Kobe CK carbonaceous chondrite: petrography, mineralogy and metamorphism

A petrographic and mineralogical study of Kobe indicates that it can be classified as a CK4 carbonaceous chondrite. CK chondrites differ from other groups of carbonaceous chondrites, because all normal CK chondrites have been thermally metamorphosed. Olivine and plagioclase are the two most abundant minerals in Kobe. Olivine is very homogeneous in composition, which is consistent with the metamorphic feature of Kobe. However, plagioclase shows large grain to grain compositional variations. The matrix and chondrule mesostases exhibit pronounced silicate darkening. They contain unusual olivine that contains numerous small vesicles (< 0.1-3 μm in diameter) and inclusions (< 0.1-10 μm) of magnetite, pentlandite and minor plagioclase, pyroxene and chlorapatite. The vesicular olivine is particularly abundant in regions that exhibit a high degree of darkening. The vesicular olivine is clearly the principal cause of the silicate darkening. Plagioclase in matrix and chondrule mesostases also contains numerous small vesicles and inclusions of magnetite, pyroxene and minor pentlandite and olivine. The texture and mineralogy of the vesicular olivine and plagioclase suggest that they recrystallized from melts that were produced from olivine and plagioclase in the matrix by shock. We suggest that the shock event occurred at a relatively mild pressure and a high temperature, probably at the state where the meteorite underwent thermal metamorphism.

Diagnostic des maladies musculaires

The clinical evaluation is an essential step to define an accurate phenotype of a myopathy. If a myogenic clinical presentation is usually easy to recognize, we must precise the topographical characteristics of the myopathic process to include it in different subgroups : facioscapulohumeral myopathy and scapuloperoneal syndrome, limb-girdle myopathy, distal myopathy, ocular myopathy… The asymetry or the selectivity of the clinical presentation is also fundamental. This topographical description is best delineated and confirmed by radiological investigations such as muscle CT scan or MRI. Additional clinical signs (early contractures, myotonia…) must be looked for as they are potentially useful to reach a final diagnosis. Serum creatine kinase levels are mandatory but sometimes unconclusive. Normal CK values do not rule out the diagnosis of myopathy. Electrophysiological studies can suggest a myopathic process but it is also very important to detect an associated neuropathy or myotonic discharges. Muscle biopsy usually remains very useful in the precise identification and the definitive diagnosis of a myopathy, even if genetic confirmation is primarily proposed in some cases.

Clinical Findings in mitochondnal neurogastrolntestinal encephalomyopathy syndrome (MNGIE)

Introduction: OXPHOS diseases are a heterogeneous group of disorders caused by mutations in mitochondrial or nuclear DNA. They display either maternal or mendellian inheritance. We describe the clinical features of four patients with MENGIE. Material and methods: clinical presentation: four patients from two families: Family A: 2 affected siblings, male and female, born from unrelated healthy parents who had healthy children in posterior marriages. The male, usually thin, developed ptosis, ophthalmoparesis, visual impairment and muscle weakness at age 13 years. Deafness and diarrhea became evident at age 37 The female developed diabetes in addition to the same clinical features. Family B: two affected children, male and female, born from noconsanguineous healthy parents. They did not gain weight after age 7 years with progressive decrease in muscle mass. They still walked at age 15, nevertheless, they had difficulties climbing stairs. In addition, they also developed ptosis and opthalmoparesis. At the age of 17 the male developed frequent diarrhea and ceased to walk. Clinical Evaluation: all the patients showed both proximal and extraocular muscle weakness with onset before the age of 20 years. Deafness, diarrhea and visual impairment appeared later. The clinical course was worse in the males Laboratory studies showed increased levels of lactate and pyruvate, normal CK, decrease of serum 1-camitine. Brain MRI revealed Increased T2 signals. EMG revealed myogenic or neurogenic abnormalities and nerve conduction alterations. Muscle biopsy showed proliferation of abnormal mitochondria Discussion: an autosomal recessive inheritance pattern was inferred because of healthy parents, recurrence in sibs and both genres being affected. The diagnosis was based on the recognition of the phenotype. the histological and ultraestructural mitochondrial abnormalities, biochemical tests, however, the diagnosis of difficult, non-classic cases is possible only by DNA analysis.

Elevated CK-MB in the presence of a normal total CK as an indicator of myocardial complication

Elevated CK-MB in the presence of a normal total CK as an indicator of myocardial complication

Immunohistochemical study on phenotypical changes of hepatocytes in liver disease with reference to extracellular matrix composition.

Extracellular matrix (ECM) may affect the function and phenotype of hepatocytes. Phenotypic changes of hepatocytes in diseased liver were investigated with reference to ECM composition. Immunohistochemistry was performed on biopsied liver samples from chronic viral hepatitis (CVH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and normal patients, using monoclonal antibodies for laminin, type IV collagen, cytokeratin 19 (CK19) and epithelial glycoprotein (EGP), a protein homologous to nidogen. In normal controls, both EGP and CK 19 were expressed exclusively on biliary epithelia. Laminin and type IV collagen were expressed around portal bile ducts and blood vessels. Although type IV collagen was expressed in Disse's space, laminin was scarcely expressed. In all pathological livers, both EGP and CK 19 were expressed in proliferated bile ductules. In CVH with piecemeal necrosis, EGP was expressed on periportal hepatocytes, while CK19 expression was limited to a few hepatocytes. Laminin was expressed in Disse's space of periportal sinusoids, where EGP was expressed on hepatocytes. EGP expression on hepatocytes and laminin deposition in Disse's space were rare in PBC and PSC liver. These results suggest that hepatocytes transform into a phenotype similar to biliary epithelia and, laminin deposition in Disse's space (capillarization of sinusoids) may play a role in this phenotypic change.

Elevated CK-MB but Normal Total CK: Grounds for Concern?

The diagnosis of acute MI is partially dependent on elevated levels of creatine kinase-MB isoenzyme. Patients may present with chest pain and a normal total CK level but also have an elevated ratio of CK-MB to total MB. Do these patients have an adverse prognosis? Investigators from Massachusetts General Hospital in …

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.

Heterophilic Antibodies Produce Spuriously Elevated Concentrations of the MB Isoenzyme of Creatine Kinase in a Selected Patient Population

Dual-site murine antibody-based immunoassays are commonly used in clinical laboratories to quantitate the MB isoenzyme of creatine kinase (CK-MB). Because the serum level of CK-MB is a relatively specific and sensitive indicator of myocardial ischemic damage, accurate quantitation is essential for a correct diagnosis. Heterophile antibodies (eg, human anti-murine antibodies) can interfere with these assays, however, and produce erroneous results. A subpopulation of 19 surgical patients with colorectal carcinoma who had received injections of an 125I-labeled murine monoclonal antibody directed against a tumor-associated glycoprotein was studied. Serum specimens from eight patients (42%) showed a marked increase in the level of CK-MB and normal total CK concentrations. The increased concentrations of CK-MB, which were attributed to interference by human antimurine antibodies, were substantially reduced in these specimens after a heterophile blocking reagent was added. However, this reagent did not significantly alter the serum level of CK-MB in patients who had clinical evidence of acute myocardial ischemia.

Cryoprostatectomy consistently elevates serum creatine kinase-MB isoenzyme

Study Objective: To measure serum CK-MB, a market of myocardial infarction (MI), in elderly men before and after cryoprostatectomy. Design: Serum CK-MB was measured on each patient before and after cryoprostatectomy. Each patient's preoperative result was used as control measurement for comparison with measurements made after cryoprostatectomy. Setting: Inpatient operating room and postanesthetic, recovery unit of a university-affiliated general hospital. Patients: 38 male patients, mean (SEM) age 69.1 ± 1.4 years, undergoing cryoprosta-tectomy. Interventions: All patients had a 12-lead ECG prior to surgery, in the recovery room, and 24 hours after surgery. Serum CK-MB was measured prior to induction of anesthesia, on arrival in the recovery room, and at 8 and 24 hours after surgery. Lactate dehydrogenase (LDH) and isoenzymes also were measured in 10 patients before and after cryoprostatectomy. Measurements and Main Results: All patients underwent uneventful cryoprostatectomy. No patients had new ECG changes after surgery. All patients had normal serum CK and CK-MB concentrations before surgery. Serum CK and CK-MB were significantly elevated after cryoprostatectomy ( p < 0.001). Enzyme values were greatest 8 hours after surgery: total CK mean 1453 ± 145 U/L (range 199 to 3,356 U/L); CK-MB mean 52 ±3 ng/ml (range 12 to 114 ng/ml) or 5.0 ± 0.5% of total CK (range 1.6% to 12.4%). All patients had significant elevations of LDH after cryoprostatectomy but did not show an increase in the ratio of LDH 1 to LDH 2 isoenzymes. Finally, unlike patients with an acute MI, the activity of CK-MB isoenzyme when measured by gel electrophoresis was two to three times greater (mean, 2.6 ± 0. 7) than the concentration measured with the monoclonal antibody assay in patients after cryoprostatectomy. Conclusion: Serum CK-MB is an unreliable test to diagnose a MI in patients who have undergone cryoprostatectomy.

804-3 A Double Blind Randomized Trial of a 24 Hour Infusion of Magnesium Sulphate in Unstable Angina

Magnesium (Mg2+) has been shown to reduce coronary spasm, have favorable hemodymamic effects, inhibit platelet function, reduce arrhythmias, modulate autonomic function, reduce catecholamine secretion and to be protective during experimental acute myocardial ischemia. Sixty-two consecutive patients with unstable angina (rest pain &lt; 24 hours, ST/T changes and normal admission CK) were randomized in a double-blind fashion to Mg2+ (8 mmol bolus, then 3.0 mmol/h for 24 hours) or placebo within 12 hours of admission. All patients received aspirin, β blockade, iv nitrates and heparin, provided no contraindications existed. Four consecutive 12 hour urine collections were started at study entry for estimation of catecholamines (n = 31) or β thromboglobulin (n = 31). 84% underwent predischarge angiography. Baseline characteristics and extent of coronary disease were similar in both groups. Serum Mg2+ rose from 0.91 ± 0.02 to 1.71 ± 0.05 mmol/l (mean ± SEM) in the Mg2+ group. CKMB release was less in the Mg2+ group at 6 and 24 hours (28.3 ± 7.4 vs 6.6 ± 1.2 ng/ml at 6 hrs, p &lt; 0.05). Regression of T wave changes on the 24 hour ECGs (compared with admission ECGs) occurred more frequently in the Mg2+ group (11 patients vs 0 patients, p &lt; 0.005). On 48 hour Holter monitoring, a similar proportion had transient myocardial ischemia (TMI) in the two groups (16 (52%) in the Mg2+ group vs 15 (48%) in the placebo group), however there were fewer episodes of TMI in the Mg2+ group (57 vs 118, p &lt; 0.0001) with a median total duration of 31.45 vs 102.73 mins respectively (p = ns). Frequency of ventricular ectopy and non-sustained ventricular tachycardia were similar in both groups. Heart rate variability was significantly lower in the placebo group in the 24 hours following, but not during, the infusion. Epinephrine excretion was lower in the Mg2+ group in the first 12 hour sample (1.05 ± 0.20 vs 1.61 ± 0.41 ng/mmol creat., p &lt; 0.051, with no significant difference in norepinephrine excretion. Urinary β thromboglobulin was similar in both groups in all collections. Thus Mg2+ appears to reduce CKMB release, ECG progression and catecholamines in the acute phase of unstable angina with no effect on β thromboglobulin excretion suggesting that its effect may be mediated via autonomic modulation but not platelet function. A larger scale trial investigating the effect of Mg2+ on mortality is warranted.

Approaching the multifaceted nature of energy metabolism: inactivation of the cytosolic creatine kinases via homologous recombination in mouse embryonic stem cells.

To study the physiological role of the creatine kinase/phosphocreatine (CK/PCr) system in cells and tissues with a high and fluctuating energy demand we have concentrated on the site-directed inactivation of the B- and M-CK genes encoding the cytosolic CK protein subunits. In our approach we used homologous recombination in mouse embryonic stem (ES) cells from strain 129/Sv. Using targeting constructs based on strain 129/Sv isogenic DNA we managed to ablate the essential exons of the B-CK and M-CK genes at reasonably high frequencies. ES clones with fully disrupted B-CK and two types of M-CK gene mutations, a null (M-CK-) and leaky (M-CK1) mutation, were used to generate chimaeric mutant mice via injection in strain C57BL/6 derived blastocysts. Chimaeras with the B-CK null mutation have no overt abnormalities but failed to transmit the mutation to their offspring. For the M-CK- and M-CK1 mutations successful transmission was achieved and heterozygous and homozygous mutant mice were bred. Animals deficient in MM-CK are phenotypically normal but lack muscular burst activity. Fluxes through the CK reaction in skeletal muscle are highly impaired and fast fibres show adaptation in cellular architecture and storage of glycogen. Mice homozygous for the leaky M-CK allele, which have 3-fold reduced MM-CK activity, show normal fast fibres but CK fluxes and burst activity are still not restored to wildtype levels.

The compositional classification of chondrites: V. The Karoonda (CK) group of carbonaceous chondrites

Petrographie and bulk compositional data reveal the existence of a new group of carbonaceous chondrites consisting of the observed fall, Karoonda, one large find from Maralinga, Australia, and 6–11 small finds from five sites in Antarctica. Ningqiang, also a fall, is genetically related to the group. Compositional, textural, and O-isotope data show that the new group is closely related to CV and CO chondrites. In keeping with the practice of naming carbonaceous chondrite groups after a prominent member, we designate it the Karoonda or CK group. All normal CK members are metamorphosed; petrographie grades range from 4 to 6. Some contain shock veins and all exhibit various degrees of blackening due to the dispersion of fine particles of sulfides and magnetite in silicates. Only one other group (EL) has no unequilibrated members. The unequilibrated Ningqiang chondrite is more similar to CK than to CV or CO chondrites, but differs significantly (e.g., low refractory lithophiles, high Mn and Na) in detailed composition. Elemental abundance patterns in CK chondrites are similar to those in CO chondrites, and even more similar to those in CV chondrites. Refractory lithophile abundances are about 1.21× greater than in CI chondrites, a level intermediate between those in CO and CV chondrites; CK refractory siderophile abundances are also intermediate between CV and CO levels. The CK volatile abundance pattern is quite similar to the CV pattern, with CK abundances of most volatiles 10–20% lower than CV values. It appears that nebular conditions and processes were closely similar at the CK and CV formation locations. Although precise probability calculations are difficult because of uncertainties regarding pairing and because so few samples are known, the exceptional abundance of CK chondrites in Antarctica requires an explanation. We suggest that compared to other groups, such as CO or CV, the fragmentation of the CK parent object(s) produced a substantially larger proportion of small meteoroids.

Application of soil chemistry to interpret cultural events at the Calderwood Buffalo Jump (DkPj‐27), Southern Alberta, Canada

AbstractDuring excavation at Calderwood Buffalo Jump (DkPj‐27), southern Alberta, two profiles were sampled for soil chemical analysis. Transect samples were subjected to the phosphate ring test. The study objectives were to examine the effects of bison‐jump use on the soil profile, to investigate whether discrete jump‐use episodes could be identified within the soil profile, and to see if the ring test was useful in site delimitation. Comparative off‐site profile samples exhibited the normal Ahk, Bmjk, and Ck sequence of a Rego Black Chernozemic soil. In contrast, samples from the primary excavation unit were enriched in organic matter and phosphorus with lower pH and higher fatty acid content. These data indicate that organic input from jump use has had a substantial impact on soil characteristics and development. A ring chromatography field test for available phosphate indicated higher values in this vicinity, suggesting the utility of this method in rapid and relatively non‐destructive field survey of similar sites. The soil chemical data suggest continuous rather than episodic jump use, contrasting with four specific episodes of jump use over the last 2800 years inferred from archaeological data.

Decreased storage stability of creatine kinase in a cardiac reperfusion solution

Creatine kinase (CK; EC 2.7.3.2) has been used as an indicator of myocardial cellular damage. In this study we used a Krebs-Henseleit (KH) solution to reperfuse isolated rat hearts after 24 h of cold preservation and collected the KH reperfusate for assay of CK to assess cellular damage. We wanted to determine the stability of CK in the KH solution at different cold-storage temperatures and albumin concentrations. CK activity (mean +/- SEM) after one week of refrigeration (5 degrees C) was 93% +/- 1% of control values, whereas CK activity in nitrogen-frozen (-200 degrees C) samples was only 1.6% +/- 1% of control values, and that in samples frozen at moderately low temperatures (-10 degrees C) was 63% +/- 1% of control values. To enhance stability, we added albumin at several concentrations (49, 25, 12, and 6 g/L) to reperfusion collections in which CK had been previously determined. Specimens were frozen (-10 degrees C), then re-analyzed for CK weekly for three weeks. CK activity was maintained (100% +/- 5%) only in samples containing 25 g/L or more albumin. These data suggest that refrigeration (5 degrees C) for one week maintains normal CK activity in KH solution; however, if prolonged storage is necessary, a stabilizer such as albumin (greater than or equal to 25 g/L) will maintain analyte stability in frozen storage (-10 degrees C) for at least three weeks.

Heterogeneity of serum creatine kinase isoenzyme MM in myocardial infarction: standardization of patterns by use of cord-blood serum.

We investigated serum creatine kinase (CK; EC 2.7.3.2) isoenzyme MM in myocardial infarction, using isoelectric focusing in polyacrylamide gels. As many as 14 sub-band species were detected, and sequential sampling revealed a progressive anodal shift in their distribution. A nomenclature for sub-band typing is proposed. It denotes the major sub-bands as 1 (pl 6.91), 2 (pl 6.65), and 3 (pl 6.35); which are usually detected in sera of normal CK range. Abnormal sub-bands (associated with increases in the concentrations of CK) are denoted as a (pl 7.55), b (pl 7.35), c (pl 7.25), d (pl 7.05), e (pl 6.85), f (pl 6.72), g (pl 6.50), h (pl 6.40), i (pl 6.28), j (pl 6.20), and k (pl 6.15). Cord-blood sera gave highly reproducible CK-MM patterns characterized by prominent detection of sub-bands 1-3 and faint detection of c, e, f, g, h, i, and j. It is recommended as a standard for CK-MM sub-band typing.

DNA probe analysis for carrier detection and prenatal diagnosis of Duchenne muscular dystrophy: a standard diagnostic procedure.

Thirteen marker loci localised on the short arm of the X chromosome are available for use in genetic studies for Duchenne muscular dystrophy (DMD). This large number of probes detecting about 20 RFLPs encouraged us to set up a standard procedure using a sequence of selected probes and restriction enzymes for the diagnosis of DMD families. The application of DNA probe analysis for carrier detection and prenatal diagnosis, involving 61 pedigrees of both familial and isolated cases, has yielded the following results. Carrier detection using flanking markers was possible in more than 75% of the cases (104 out of 136 females) with a reliability of better than 98%. Prenatal diagnosis was possible in 95% of the cases (65 out of 68 proven carriers or women at risk). Twenty-three prenatal diagnoses were performed on male fetuses; 13 appeared to have a low risk for DMD (less than 1%) and thus the pregnancies continued. Seven have since come to term and the male infants have normal CK levels. The genetic distances of the loci relative to the DMD locus and their order on the short arm of the X chromosome were deduced from our total DMD family material and are not significantly different from those reported earlier. For 754 (DXS84) we found a genetic distance of 5 cM with a lod score of +12.4 and 95% confidence limits between 2 and 12 cM. Similar data were obtained for pERT87 (DXS164), suggesting that in our family material both loci are tightly linked. Multiply informative recombination showed that both 754 and pERT87 map proximal to the DMD mutations in the cases studied. The high frequency of DMD mutations and its relation to the observed instability in this part of the genome will be discussed. Unequal crossing over is proposed as one of the mechanisms contributing to the high mutation frequency.

Quantitative analysis of quadriceps muscle biopsy: Results in 7 definite and 45 possible carriers of duchenne muscular dystrophy

Quadriceps muscle biopsy was performed in 7 definite and 45 possible carriers of Duchenne muscular dystrophy. Unequivocal morphological changes were observed in 8 women; all but one of them were already detected as carriers by increased serum CK. Histometric analysis of muscle biopsy was performed on two fibre types (type 1 and type 2) in all 52 women; in 38 of them the two subgroups of type 2 fibres (type 2a and type 2b) were also quantified. Results of histometric analysis were matched with control values obtained from 30 healthy females in the same age as the carriers (20–50 yr). Histometric analysis on two fibre types detected a percentage of carriers (27%) much lower than that detected by serum CK determination (44%). The detection rate of combined serum CK determination and histometric analysis of muscle biopsy was: 100% in definite carriers, 65% in mothers possible carriers, 38% in sisters and 25% in the group of cousins and aunts. The histometric parameters most frequently altered were atrophy factor and variability coefficient of mean diameter. Histometric analysis carried out on three fibre types in 38 women detected 2 more carriers showing atrophy of type 2b fibres. The results indicate that quantitative analysis of muscle biopsy may be used to detect some possible carriers with normal serum CK. However, an adequate number of controls is mandatory; in fact the detection rate of histometric analysis of muscle biopsy decreased by increasing the number of controls, resulting much lower than previously reported.

Indices for the age of the creatine kinase M-chain in the blood

The apparent activation energy of the CK reaction as well as the Michaelis-Menten constants and the isoelectric point of CK MM can be used as indices for the mean age of the CK M-chain in the blood in vivo and in vitro. Modifications in the CK M-chain take place in vivo in the blood and in vitro in a serum matrix. Gradual increases in the apparent activation energy are also observed both in vivo and in vitro. It is confirmed that the modification in the CK M-chain causes a rise in the apparent activation energy, u. A gradual increase in apparent activation energy, due to the ageing process of the CK M-chain, was observed after myocardial infarction. A significantly increased value for u was observed at the time that total CK activity already had returned to reference values. In spite of the normal CK value, the apparent activation energy still indicated that there had been myocardial damage. The Michaelis-Menten constants for creatine phosphate and ADP are also influenced significantly by the modification in the M-chain. While the apparent activation energy increases, the Michaelis constants decrease in the order MM 3, MM 2, MM 1. The Michaelis-Menten constants for both ADP and CrP can be used as an index for the mean age of the enzyme in the blood. The Michaelis-Menten constants for CrP and ADP show significant variations with the measuring temperature for virtually all CK MM forms.

Lactate dehydrogenase isoenzyme 1: its usefulness as a screening test in diagnosis of myocardial infarction

Immunological assay of LD-1 activity provides a quantitative measurement of the type of lactate dehydrogenase (LD, EC 1.1.1.27) activity characteristic of myocardial origin. Using this test, a laboratory diagnosis of myocardial infarction can be either ruled out or confirmed in approximately 75% of patients in whom this diagnosis is suspected, without electrophoretic separation of creatine kinase (CK, EC 2.7.3.2.) and LD isoenzymes. Normal total CK and LD activities cannot be used to rule out myocardial infarction since CK-MB and LD-1 may have increased although total activities remain within their reference ranges. LD-1 activity increases as quickly as CK-MB following the onset of pain in the majority of patients but it remains elevated longer giving a greater period of time during which the diagnosis of myocardial infarction can be confirmed.

A new creatine kinase found in mitochondrial extracts from malignant liver tissue

A new creatine kinase (CK, ATP: creatine N-phosphotransferase, EC 2.7.3.2) band was found in mitochondrial extracts prepared from malignant liver tissue. By agar gel electrophoresis the new band (CKmLT) migrated between CK-MM and a sample application point. The CK band was not found in mitochondrial extracts of normal liver, cytosolic extracts of normal and malignant liver homogenates. We thus presume that the origin of CKmLT is from mitochondria of malignant liver tumors. CKmLT reacted with anti-mitochondrial CK antibodies so that its antigenicity was similar to that of mitochondrial CK. Physico-chemical characteristics were similar to those of the polymeric form of the normal liver mitochondrial CK (CKmL 1); i.e. relative molecular mass (320000 to 350000), heat stability, and the behavior in 2 mol/1 urea. CKmLT migrated to the CKmL 1 and the MM position after long-term storage at −20°C. CKmLT did not demonstrate affinity to concanavalin A, and there was no significant change in the electrophoretic mobility of CKmLT following neuraminidase treatment.