Decreased serum biochemical markers of muscle origin in patients with ankylosing spondylitis.
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OBJECTIVES: There is a lack of unanimity about (increased) serum levels of creatine kinase (CK) in patients with ankylosing spondylitis (AS), perhaps because of the inclusion of inappropriate controls. Therefore, serum levels of biochemical markers of muscle origin were assessed in AS patients compared with controls. METHODS: In a comparative study serum levels of sarcoplasmic proteins indicating muscle cell leakage, creatinine, and C reactive protein (CRP) were measured. Fifty eight AS patients with a mean disease duration of 22 (SD 11) years and 58 age and sex matched controls (without back complaints) were included. RESULTS: Lower serum levels in AS patients compared with controls were found for CK (mean (SD): 46 (21) v 76 (44) IU/l; p<0.001), aldolase (0.43 (0.36) v 0.58 (0. 32) IU/l; p=0.001), creatinine (91 (13) v 96 (11) micromol/l; p=0. 02), alanine aminotransferase (2.8 (1.5) v 4.1 (2.9) IU/l; p=0.001) and aspartate aminotransferase (7.0 (2.7) v 8.4 (3.5) IU/l; p=0.02). Also the lean body mass, as estimated by a formula using height, weight, age and sex, showed lower values in patients versus controls (56 (9) v 59 (9) kg; p=0.004), but creatinine clearance (by Cockcroft and Gault formula) was not different (p=0.48). Partial correlation coefficients adjusted for age and sex showed that CRP levels correlated negatively with CK and aldolase levels in AS patients (r= -0.48, p<0.001 and r= -0.37, p=0.005, respectively). CONCLUSION: Serum levels of biochemical markers of muscle origin were lower in AS patients compared with controls. Patients with active AS, as reflected by high CRP levels, may have an increased protein degradation, predominantly in skeletal muscle. (+info)
Increased cardiac troponin T and endothelin-1 concentrations in dialysis patients may indicate heart disease.
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BACKGROUND: Cardiac troponin T (cTnT) is a highly sensitive marker for the detection of myocardial damage. However, patients maintained on chronic dialysis often have increased serum cTnT concentrations without evidence of acute myocardial injury. The reason for this is unclear. In chronic haemodialysis patients, elevated plasma concentrations of big endothelin-1 (big ET-1) and endothelin-1 (ET-1) have been reported which may be associated with ischaemic heart disease. The aim of the present study was to investigate possible associations between cTnT, big ET-1, ET-1, other cardiac markers and cardiac disease in dialysis patients. METHODS: Thirty-six haemodialysis (HD) patients and 26 peritoneal dialysis (PD) patients without symptoms of acute myocardial ischaemia were investigated. In all patients, serum concentrations of cTnT (2nd generation ELISA), cardiac troponin I (TnI) (Opus, Behring), creatine kinase MB (CKMB) mass and creatine kinase (CK) were determined, in HD patients before and after dialysis. Additionally, in HD patients, plasma ET-1 and big ET-1 were measured. In 27 HD patients, left ventricular mass index (LVMI) was determined. Patients with ischaemic heart disease (IHD) were compared with non-IHD patients. RESULTS: Serum cTnT was elevated (> or =0.10 microg/l) in 20 of 36 HD patients and in eight of 26 PD patients. cTnI was elevated (> or =0.5 microg/l) in four of 62 dialysis patients. HD+PD patients with IHD showed higher cTnT than HD+PD patients without IHD, and ET-1 concentrations were higher in HD patients with than without IHD. In HD patients, there was a positive correlation between cTnT and big ET-1. In HD patients with left ventricular hypertrophy (LVH), serum cTnT, CKMB mass and post-dialysis plasma big ET-1 were higher than in patients with normal LVMI. Furthermore there was a positive correlation between cTnT levels and LVMI. CONCLUSION: These findings suggest that circulating cTnT may reflect left ventricular hypertrophy and/or myocardial ischaemia in dialysis patients, and indicate that ET-1 and big ET-1 might be associated with these conditions. (+info)
Creatine kinase reaction in skinned rat psoas muscle fibers and their myofibrils.
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The aim of this study was to evaluate myofibrillar creatine kinase (EC 2.7.3.2) activity on the background of the effect of substrate channeling by myosin ATPase and to compare it with creatine kinase (CK) activity of whole skinned fibers. In order to assess CK activity, skinned fibers were prepared from the rat psoas major muscles defined by light microscopy. The activity in permeabilized fibers after treatment with saponin, Triton X-100 and Ca(2+)-free medium reached 2.80, 6.97 and 3.32 micromol ATP min(-1) mg(-1) protein, respectively, when a coupled enzyme assay system with external hexokinase and glucose-6-phosphate dehydrogenase was used. Transmission electron microscopy (TEM) revealed a possible interference among activities of sarcolemmal, sarcoplasmic, myofibrillar and mitochondrial CK from persisting structures. For evaluation of the myofibrillar CK itself, a pure myofibrillar fraction was prepared. Fraction purity was confirmed by TEM and by enzymatic assays for marker enzymes. Two procedures, i.e. the coupled enzyme assay and the evaluation of phosphocreatine (PCr) concentration before and after the CK reaction, were used for measurement of CK activity in this fraction. The procedures resulted in 3.2 nmol ATP min(-1) mg(-1) protein and 7.6 nmol PCr min(-1) mg(-1) protein, respectively. These alternative approaches revealed a discrepancy between the reacting portions of PCr by more than 50 %, which provides information about the size of the effect, generally described as substrate channeling. (+info)
Standardization of creatine kinase-MB (CK-MB) mass assays: the use of recombinant CK-MB as a reference material.
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BACKGROUND: The AACC assembled a committee to identify and validate a standard creatine kinase MB isoenzyme (CK-MB) material to improve the comparability of CK-MB mass assays. METHODS: Three protocols were used. In protocol I, various CK-MB materials prepared in different matrices were screened as candidate standards. In protocol II, participating manufacturers calibrated their systems with concentrates of human heart CK-MB and then tested 20 patient samples to evaluate calibration bias. In protocol III, participating manufacturers calibrated their immunoassay systems using recombinant CK-MB2 (rCK-MB2) diluted into their respective sample diluents and measured 50 samples. RESULTS: Candidate materials showed high recovery in stripped human serum, but bias improved only from 59% to 38%. These data led to the use of human heart CK-MB diluted in each manufacturer's sample diluent. This strategy reduced bias from 31% to 15%. Because human heart CK-MB is difficult to provide, a lyophilized source of CK-MB2 was identified. rCK-MB2 was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, reversed-phase HPLC, intrinsic protein fluorescence, circular dichroism, agarose gel electrophoresis, immunoreactivity studies, high and low temperature stability, and reconstituted stability to be equivalent to human heart CK-MB. Calibration of immunoassay systems with rCK-MB2 added into each respective manufacturer's sample diluent showed a 13% between-manufacturer bias. CONCLUSION: Lyophilized rCK-MB2 was determined suitable for use as a reference material for CK-MB mass assays. (+info)
Prognostic value of serum hepatocyte growth factor in patients with acute coronary syndromes.
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The present study examined whether or not hepatocyte growth factor (HGF), an endothelium-specific growth factor that stimulates regeneration of the endothelium, is increased or has a prognostic significance in patients with acute coronary syndromes. HGF was measured in 106 patients with coronary artery disease (20 stable effort angina, 12 unstable angina without adverse events, 24 unstable angina with adverse events and 50 acute myocardial infarction) on admission and 21 normal volunteers. The measurements in all patients were recorded before administration of heparin, and in acute myocardial infarction patients they were recorded from days 2 to 6 after heparin discontinuation on day 1. HGF levels (ng/ml) were 0.30+/-0.06 for the controls, 0.31+/-0.08 for stable effort angina patients, 0.31+/-0.08 for unstable angina patients without adverse events, 0.40+/-0.20 for unstable angina patients with adverse events and in acute myocardial infarction patients they were 0.45+/-0.18 on day 0, 0.57+/-0.45 on day 2, 0.50+/-0.35 on day 3, 0.48+/-0.32 on day 4, 0.44+/-0.20 on day 5, and 0.38+/-0.14 on day 6. HGF plays a crucial role in the restoration of injured endothelial cells and is a predictor of adverse events in patients with acute coronary syndromes. (+info)
Effects of Ca, Mg, and EDTA on creatine kinase activity in cerebrospinal fluid.
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For one to obtain a precise estimate of creatine kinase (CK) activity in cerebrospinal fluid, the sample fraction is increased by about 10-fold over that used for serum. This increases the concentration of interfering substances, Ca being especially important. Therefore, the relationship between Ca, Mg, and EDTA was examined. Enzyme activity was maximal with 15 mmol of Mg per liter in the presence of 3 mmol of EDTA per liter, otherwise according to the (Scandinavian) recommended conditions for determination of CK activity in serum. These modifications increased the activity of CK by 35% for CK-MM and by 60% for CK-BB. Counteraction of Ca-induced inhibition was the main reason to this increase. We describe a practical and sensitive method for determining CK in cerebrospinal fluid. (+info)
Creatine kinase-MB elevation after coronary intervention correlates with diffuse atherosclerosis, and low-to-medium level elevation has a benign clinical course: implications for early discharge after coronary intervention.
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OBJECTIVES: The study evaluated the incidence and predictors of creatine kinase-MB isoenzyme (CK-MB) elevation after successful coronary intervention using current devices, and assessed the influence on in-hospital course and midterm survival. BACKGROUND: The CK-MB elevation after coronary intervention predominantly using balloon angioplasty correlates with late cardiac events of myocardial infarction (MI) and death. Whether CK-MB elevation after nonballoon devices is associated with an adverse short and midterm prognosis is unknown. METHODS: The incidence and predictors of CK-MB elevation after coronary intervention were prospectively studied in 1,675 consecutive patients and were followed for in-hospital events and survival. RESULTS: CK-MB elevation was detected in 313 patients (18.7%), with 1-3x in 12.8%, 3-5x in 3.5% and >5x normal in 2.4% of patients. Procedural complications or electrocardiogram changes occurred in only 49% of the CK-MB-elevation cases; CK-MB elevation was more common after nonballoon devices (19.5% vs. 11.5% after percutaneous transluminal coronary angioplasty; p < 0.01). Predictors of CK-MB elevation on multivariate analysis were diffuse coronary disease (p = 0.02), systemic atherosclerosis (p = 0.002), stent use (p = 0.04) and absence of beta-blocker therapy (p = 0.001). Adverse in-hospital cardiac events were more frequent in patients with >5x CK-MB elevation, with no significant difference between 1-5x CK-MB elevation versus normal CK-MB group. During a mean follow-up of 13 +/- 3 months, the incidence of death in the CK-MB-elevation group was 1.6% versus 1.3% in the normal CK-MB group (p = NS). CONCLUSIONS: The CK-MB elevation after coronary intervention was observed even in the absence of discernible procedural complications and was more common in patients with diffuse atherosclerosis. In-hospital clinical events requiring prolonged monitoring were higher in >5x CK-MB-elevation patients only. Midterm survival of CK-MB-elevation patients was similar to those with normal CK-MB. Our prospective analysis shows a lack of adverse in-hospital cardiac events and suggests that early discharge of stable 1-5x normal CK-MB-elevation patients after successful coronary intervention is safe. (+info)
Myoglobin, creatine-kinase-MB and cardiac troponin-I 60-minute ratios predict infarct-related artery patency after thrombolysis for acute myocardial infarction: results from the Thrombolysis in Myocardial Infarction study (TIMI) 10B.
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OBJECTIVES: We examined the diagnostic performance of serum myoglobin, creatine-kinase-MB (CK-MB) and cardiac troponin-I (cTnI) for predicting the infarct-related artery (IRA) patency in patients receiving TNK-tissue plasminogen activator (TNK-tPA) therapy for acute myocardial infarction (AMI) in the Thrombolysis in Myocardial Infarction (TIMI) 10B trial. BACKGROUND: A reliable noninvasive serum marker of IRA patency is desired to permit early identification of patients with a patent IRA after thrombolysis. METHODS: We measured myoglobin, CK-MB and cTnI concentrations in sera obtained just before thrombolysis (T0) and 60 min later (T60) in 442 patients given TNK-tPA and who underwent coronary angiography at 60 min. RESULTS: Angiography at 60 min showed a patent IRA (TIMI flow grade 2, 3) in 344 and occluded IRA (TIMI flow grade 0, 1) in 98 patients. The median serum T60 concentration, the ratio of the T60 and T0 serum concentration (60-min ratio) and the slope of increase over 60 min for each serum marker were significantly higher in patients with patent arteries compared with patients with occluded arteries. The area under the receiver-operating characteristic (ROC) curve for diagnosis of occlusion was 0.71, 0.70 and 0.71 for the 60-min ratio of myoglobin, cTnI and CKMB, respectively. The 60-min ratios of > or =4.0 for myoglobin, > or =3.3 for CK-MB and > or =2.0 for cTnI yielded a probability of patency of 90%, 88% and 87%, respectively. CONCLUSIONS: The diagnostic performance of serum myoglobin, CK-MB and cardiac troponin-I (cTnI) 60-min ratios was similar. The probability of a patent IRA was very high (90%) in patients with 60-min myoglobin ratio > or =4.0, and early invasive interventions to establish IRA patency may not be necessary in this group. Serum marker determinations at baseline and 60-min after thrombolysis may permit rapid triage of patients receiving thrombolytic therapy by ruling out IRA occlusion. (+info)