Circulating tumor DNA methylation marker MYO1-G for diagnosis and monitoring of colorectal cancer

BACKGROUND

Circulating tumor DNA (ctDNA) is a promising diagnostic and prognostic marker for many cancers and has been actively investigated in recent years. Previous studies have already demonstrated the potential use of ctDNA methylation markers in the diagnosis and prognostication of colorectal cancer (CRC). This retrospective study validated the value of methylation biomarker MYO1-G (cg10673833) in CRC diagnosis and disease monitoring using digital droplet PCR (ddPCR), a biomarker selected from our previous study due to its highest diagnostic efficiency.

METHODS

Blood samples of CRC and control samples from tumor-free individuals at two institutions were collected to quantify the methylation ratio using ddPCR. Area under curve (AUC) was calculated after constructing receiver operating characteristic curve (ROC) for CRC diagnosis. Sensitivity and specificity were estimated and comparisons of methylation ratio in different groups were performed.

RESULTS

We collected 673 blood samples from 272 patients diagnosed with stage I-IV CRC and 402 normal control samples. The methylation biomarker discriminated patients with CRC from normal controls with high accuracy (area under curve [AUC] = 0.94) and yielded a sensitivity of 84.3% and specificity of 94.5%. Besides, methylation ratio of MYO1-G was associated with tumor burden and treatment response. The methylation ratio was significantly lower in patients after their radical operation than when compared with those before surgeries (P < 0.001). Methylation ratio was significantly higher in patients with disease progression than those with stable disease (P = 0.002) and those with complete response or partial response (P = 0.009).

CONCLUSIONS

Together, our study indicated that this methylation marker can serve as a potential biomarker for diagnosing and monitoring CRC.

[Enzymatic activity of some tissues and blood serum from animals and humans exposed to microwaves and hypothesis on the possible role of free radical processes in the nonlinear effects and modification of emotional behavior of animals]

The dependence of activities of actomyosin ATPase, alkaline phosphatase, aspartataminotranspherase, monoaminoxidase and that of affective rat behavior on frequency of modulation of microwaves (0.8-10 microW/cm2) was explored at short-time actions. Series of nonlinear phenomenons, inexplicable from positions of the energy approaches are revealed, The working hypothesis explaining opportunity of high performance of weak and super-weak microwaves and other revealed phenomena by resonance interaction of such electromagnetic radiofrequency radiation with paramagnetic molecules of biological tissues was proposed. This resonance interaction activate free radicals and initiate auto-supporting and auto-intensifying of chain chemical reactions. The spontaneous autocatalytic oxidation of catecholamines enlarges a common pool of free radicals, capable to participate in such enhanced generating. The protective role of monoaminoxidase is postulated. Monoaminoxidase is basically located on an outer surface of mitochondrias and it is deaminating monoamines. The deaminating prevents penetration of catecholamines inside of mitochondrias and their quinoid oxidation there with formation of free-radical semi-quinons, capable to destroy system of ATP synthesis. These inferences are obliquely confirmed by the experimentally revealed correlation between activity of monoaminoxidase and integrative activity of the rat brain.

Diagnostic implications of elevated levels of smooth-muscle myosin heavy-chain protein in acute aortic dissection. The smooth muscle myosin heavy chain study

BACKGROUND

A rapid 30-minute assay of circulating smooth-muscle myosin heavy-chain protein has been developed as a biochemical diagnostic tool for aortic dissection.

OBJECTIVE

To determine the sensitivity and specificity of this assay.

DESIGN

Cross-sectional study.

SETTING

8 major cardiovascular centers in Japan.

PATIENTS

95 patients with acute aortic dissection, 48 patients with acute myocardial infarction, and 131 healthy volunteers.

MEASUREMENTS

Levels of circulating smooth-muscle myosin heavy-chain protein.

RESULTS

Patients with acute aortic dissection who presented within 3 hours after onset had elevated levels of circulating smooth-muscle myosin heavy-chain protein. In these patients, the assay had a sensitivity of 90.9%, a specificity of 98% compared with healthy volunteers, and a specificity of 83% compared with patients who had acute myocardial infarction; the clinical decision limit was 2.5 microgram/L. All patients with proximal lesions had elevated levels of smooth-muscle myosin heavy-chain protein, and only patients with distal lesions had decreased levels (<2.5 microgram/L).

CONCLUSIONS

Levels of smooth-muscle myosin heavy-chain protein can be used to diagnose aortic dissection soon after symptom onset. The assay had the greatest diagnostic value in patients with proximal lesions.

Effect of upper gastrointestinal endoscopy on circulation in the elderly

BACKGROUND

Upper gastrointestinal endoscopy in the elderly is increasingly becoming more common, despite the possibility that a minimal load on the circulation can cause serious complications such as shock and cardiac arrest.

OBJECTIVE

The effects of endoscopy on the heart and the possibility of predicting circulatory accidents were studied using natriuretic peptide levels.

METHODS

The patients were randomly chosen according to their age and divided into an elderly group (over 60 years of age, 64 patients) and a young group (under 30 years of age, 20 patients). The patients in the elderly group were further subdivided into two groups based on the presence or absence of circulatory complications (46 patients with circulatory complications and 18 without complications). The load on the heart was evaluated by measuring human atrial natriuretic peptide (hANP) and human brain natriuretic peptide (hBNP) which are secreted by the myocardial cells in response to cardiac load. Specimens were obtained before and after endoscopy.

RESULTS

The hANP level was significantly higher after endoscopy in the elderly group, regardless of the presence or absence of circulatory complications. No significant difference was observed in the hBNP level. No significant increase in hANP or hBNP levels was observed after endoscopy in the young group.

CONCLUSIONS

These observations suggest an increased atrial load during endoscopy in the elderly. The increase in pulse rate during endoscopy is one possible cause of atrial load. Therefore, the risk of circulatory system damage must be recognized when endoscopy is performed in the elderly. The measurement of plasma hANP and hBNP levels may provide effective indices for evaluating cardiac load during endoscopy.

Agonist-induced regulation of myosin phosphatase activity in human platelets through activation of Rho-kinase

Human platelets contained about 15 times lower amounts of Rho-kinase than Ca2+/calmodulin-dependent myosin light chain (MLC) kinase. Anti-myosin-binding subunit (MBS) antibody coimmunoprecipitated Rho-kinase of human platelets, and addition of GTPgammaS-RhoA stimulated phosphorylation of the 130-kD MBS of myosin phosphatase and consequently inactivated myosin phosphatase. Two kinds of selective Rho-kinase inhibitors, HA1077 and Y-27632, reduced both GTPgammaS-RhoA-dependent MBS phosphorylation and inactivation of the phosphatase activity. Activation of human platelets with thrombin, a stable thromboxane A2 analog STA2, epinephrine, and serotonin resulted in an increase in MBS phosphorylation, and the agonist-induced MBS phosphorylation was prevented by pretreatment with the respective receptor antagonist. HA1077 and Y-27632 inhibited MBS phosphorylation in platelets stimulated with these agonists. These compounds also blocked agonist-induced inactivation of myosin phosphatase in intact platelets. In addition, HA1077 and Y-27632 inhibited 20-kD MLC phosphorylation at Ser19 and ATP secretion of platelets stimulated with STA2, thrombin (0.05 U/mL), and simultaneous addition of serotonin and epinephrine, whereas these compounds did not affect MLC phosphorylation or ATP secretion when platelets were stimulated with more than 0.1 U/mL thrombin. Thus, activation of Rho-kinase and the resultant phosphorylation of MBS is likely to be the common pathway for platelet activation induced by various agonists. These results also suggest that Rho-kinase-mediated MLC phosphorylation contributes to a greater extent to the platelet secretion induced by relatively weak agonists.

Calculation of a Gap restoration in the membrane skeleton of the red blood cell: possible role for myosin II in local repair

Human red blood cells contain all of the elements involved in the formation of nonmuscle actomyosin II complexes (V. M. Fowler. 1986. J. Cell. Biochem. 31:1-9; 1996. Curr. Opin. Cell Biol. 8:86-96). No clear function has yet been attributed to these complexes. Using a mathematical model for the structure of the red blood cell spectrin skeleton (M. J. Saxton. 1992. J. Theor. Biol. 155:517-536), we have explored a possible role for myosin II bipolar minifilaments in the restoration of the membrane skeleton, which may be locally damaged by major mechanical or chemical stress. We propose that the establishment of stable links between distant antiparallel actin protofilaments after a local myosin II activation may initiate the repair of the disrupted area. We show that it is possible to define conditions in which the calculated number of myosin II minifilaments bound to actin protofilaments is consistent with the estimated number of myosin II minifilaments present in the red blood cells. A clear restoration effect can be observed when more than 50% of the spectrin polymers of a defined area are disrupted. It corresponds to a significant increase in the spectrin density in the protein free region of the membrane. This may be involved in a more complex repair process of the red blood cell membrane, which includes the vesiculation of the bilayer and the compaction of the disassembled spectrin network.

Dual image of myosin and actin in human neutrophils during movement by fluorescence microscopy

It is well known that myosin and actin play important roles as a motile apparatus in cells, and as a cytoskeleton of cell structure in non-muscle cells. The purpose of this study was simultaneously to demonstrate the intracellular dynamics of myosin and actin in human neutrophils during movement. We designed a double-fluorescence labelling procedure utilising fluorescein isothiocyanate and rhodamine. Myosin was labelled with the green-fluorescence, F-actin was labelled with the red-fluorescence and the coexisting myosin and F-actin were labelled with yellow-fluorescence. We obtained the dual image of myosin and F-actin in human neutrophils during movement by this procedure through a conventional fluorescence microscope. Dual image can interpret the relationship between myosin and actin in human neutrophils during movement, however, further studies are required to elucidate the contractile mechanism in such cells.

The intracellular distribution patterns of myosin and actin are different among human neutrophils and monocytes during locomotion

BACKGROUND AND OBJECTIVE

Neutrophils and monocytes initiate their characteristic ameboid movement by using mechanochemical systems of contractile proteins. It is known that neutrophils and monocytes exhibit differing patterns of motility. We set out to determine whether these differences may be associated with the intracellular distribution of myosin and actin, the principle components of the cellular apparatus involved in motility.

METHODS

Myosin and F-actin in human neutrophils and monocytes were observed at resting and motile stages by using a double-fluorescence staining procedure and a confocal laser scanning microscope.

RESULTS

In motile neutrophils, myosin was distributed in the lamellipodia and the cytoplasm, observed as a speckled pattern, whereas F-actin was concentrated in the front of the lamellipodia and in the perinuclear area. In the motile monocytes, myosin was found in the wide lamellipodia and was seen to radiate from the cytoplasm towards the edges of the cell in a punctate pattern. F-actin was densely distributed along the leading edge of the wide lamellipodia as well as in the perinuclear region. No differences were apparent in the intracellular distribution of myosin and F-actin between the resting neutrophils and monocytes.

INTERPRETATION AND CONCLUSIONS

Findings indicate that differing patterns of arrangement of myosin and actin in the lamellipodia and cytoplasm of neutrophils and monocytes may contribute to their movement, in vitro.

[Value of human cardiac troponin I determination in the diagnosis of acute myocardial infarction]

Immunoenzymatic assay (IEMA) of human cardiac Troponin I (TnI c) was used in patients admitted to the coronary care unit with acute myocardial infarction (AMI). TnI c was detected in all patients with AMI. The detection of TnI c was earlier after the onset of pain (4.5 +/- 2.3 hours) than that of CKMB activity (6.3 +/- 3.6 hours), p = 0.003. The kinetics of TnI c are usually monophasic and parallel to that of CKMB activity. The peak value occurs 12.2 +/- 4.6 hours and 15.8 +/- 9.0 hours after the onset of pain in patients treated by thrombolysis. The TnI c disappears from the plasma between 5 and 9 days after the onset of pain, later than CKMB activity (p = 0.0001). In 49 patients admitted for AMI treated by thrombolysis, the comparative sensitivities of TnI c (threshold: 0.1 ng/ml) and of CKMB activity (threshold: 15 IU/l; CK > or = 100 Ul/l) were, at the first sampling on admission, 61% and 22% respectively (p = 0.0002) (average interval from onset of pain to first blood sampling: 3.4 +/- 1.3 hours). TnI c was not detected in the plasma of 145 normal subjects nor in any of the 6 patients with severe muscular trauma or rhabdomyolosis (specificity: 100%). This IEMA is a specific and a sensitive method of diagnosing acute and subacute myocardial infarction. It is ideal for the detection of myocardial necrosis in complex clinical situations when the usual enzymatic markers may be ineffective.

Assessment of radical activity during the acute phase of myocardial infarction following fibrinolysis: utility of assaying plasma malondialdehyde

Numerous experimental and clinical studies have reported a role of radical forms of oxygen in the etiology of the manifestations of reperfusion of the ischemic myocardium. However, clinical results remain controversial. The aim of this study was to ascertain the existence of reperfusion-related radical stress after thrombolysis with a marker that is easy to use and reliable. Thirty patients hospitalized for acute myocardial infarction were involved in the study. Of these, 18 had been subjected to intravenous thrombolysis (Group I) and 12 had not (Group II). They were compared to two control groups who had no history of myocardial infarction. Of these, 16 were patients with coronary heart disease hospitalized for stable angina (Group III) and 17 were patients free of any known cardiovascular disease (Group IV). Radical activity was assessed in plasma samples taken from a peripheral vein over a 10-day period of hospitalization by measuring (1) malondialdehydes (MDA) concentrations using fluorometry techniques or HPLC, (2) the antioxidant activity of glutathione peroxidase (GPx) and (3) the concentration of various antiradical compounds (beta-carotene, vitamins A and E, uric acid). All patients in Group I had a patent artery on coronary angiography and showed a significant increase in plasma MDA when compared to those who had not been subjected to thrombolysis (3.15 +/- 0.62 and 2.70 +/- 0.40 mole/l of plasma, respectively). Furthermore, GPx plasma activity was also significantly increased following thrombolysis. By contrast, there was no significant alteration in the antiradical compounds measured. These data suggest that MDA measurements (an early measurement 1-2 days and a late measurement 5-7 days after reperfusion) by fluorometry is a good marker of radical stress during reperfusion in man. The assessment of this marker in patients might represent a simple and reliable test of reperfusion efficacy following thrombolysis, and it might enable one to test the effect of various antioxidant therapies associated with thrombolytic treatment.

A novel immunoassay of smooth muscle myosin heavy chain in serum

We have developed a double monoclonal sandwich enzyme immunoassay to measure smooth muscle myosin heavy chain (MHC). Analytical performance of the assay showed reliable detection of smooth muscle MHC in human sera. The mean of the smooth muscle MHC level in normal human sera was 0.9 +/- 0.9 ng/ml. In sera of patients with aortic dissection, the smooth muscle MHC level sharply elevated at the onset and rapidly decreased to normal levels. Immunoassay of smooth muscle MHC in serum is a promising method for biochemical diagnosis of smooth muscle disorders.

[Time-course changes in serum myosin light chain 1 concentration and clinical implication in patients with reperfused acute myocardial infarction]

The correlation between the time-course changes in the serum concentration of myosin light chain 1 (ML-1) and left ventricular (LV) function was investigated in 37 patients with initial anterior acute myocardial infarction (AMI) after successful reperfusion. All patients were confirmed to have coronary arteries recanalized to TIMI grade 3 within 6 hours of AMI and patent arteries about 2 weeks after recanalization. LV function was assessed by left ventriculography. The patients were divided into two groups according to the time-course changes in the serum concentration of ML-1; 20 who showed an early peak of the serum ML-1 level within 24 hours and a late peak 3 to 5 days after recanalization (bimodal pattern: group B), and 17 who showed a single peak of the serum ML-1 level after recanalization (unimodal pattern: group U). The sum of ST elevation in an electrocardiogram before reperfusion and the additional ST elevation during reperfusion were both greater in group B than in group U (p < 0.1 and p < 0.05, respectively). The peak serum concentration of creatine kinase was significantly greater in group B than group U. LV dilatation was more extensive and the improvement of LV function was poorer in group B compared to group U.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of five cardiac markers in the detection of reperfusion after thrombolysis in acute myocardial infarction

OBJECTIVE

To investigate and compare the clinical usefulness of serial measurements of five cardiac marker proteins, namely creatine kinase (CK), CK-MB mass, myoglobin, troponin T, and myosin light chain 1, in the early detection of reperfusion after thrombolytic treatment.

METHOD

Serial blood samples were taken from 26 patients presenting with acute myocardial infarction. Concentrations of the five markers were assayed in each sample. Thrombolytic treatment was given to the patients who were divided into those who reperfused (n = 17, group A) and those who failed to reperfuse (n = 9, group B) on the basis of clinical signs and angiography within 24 h.

RESULTS

The release profiles of CK, CK-MB mass, myoglobin, and troponin T for patients in group A differed from those of patients in group B. No difference was observed in the release profile of myosin light chain 1 between the two groups. The time to peak concentration of CK, CK-MB mass, myoglobin, and troponin T occurred significantly earlier in patients of group A than in those of group B, with myoglobin peaking earlier than the other markers. An index, defined as the ratio of the concentration of each marker immediately before and 2 h after the start of thrombolytic treatment, was calculated for each marker in groups A and B. The 2 h myoglobin and troponin T indices were significantly different between groups A and B. The diagnostic efficiency of the myoglobin index, however, was best at 85%.

CONCLUSIONS

These studies suggest that myoglobin has greater potential than the other markers examined in the detection of reperfusion after thrombolytic treatment.

Abnormal subcellular distribution of myosin and talin in Wistar Furth rat platelets

The roles of most cytoskeletal proteins in platelet formation and function remain largely undefined. We earlier detected megakaryocyte membrane blebbing and a unique antigenic determinant associated with a missense mutation in the cytoskeletal protein, talin, in an animal model of hereditary macrothrombocytopenia, the Wistar Furth (WF) rat, which led us to examine the distribution of talin and other cytoskeletal proteins in resting normal and WF rat platelets. In contrast to the conclusions of an earlier ultrastructural analysis, our biochemical and ultrastructural immunogold studies indicate a significant membrane-association of talin in both resting normal and WF rat platelets as found earlier for rat megakaryocytes. Talin was associated with plasma membranes, membranes of the surface-connected canalicular system, and with alpha-granule membranes of both normal and WF rat platelets, but as in WF megakaryocytes, talin was absent from the large membrane complexes of WF platelets. An even more striking difference was seen in the distribution of myosin in subcellular fractions of normal and WF rat platelets separated in density gradients, in which the proportion of myosin in the least dense WF rat platelet membrane fraction was one half that in the same normal platelet fraction. This difference was balanced by a fourfold increase in myosin in the most dense WF rat subcellular fraction, which is highly enriched for alpha-granules. These results support our hypothesis that the platelet abnormalities of the WF rat are related to defects in the megakaryocyte-platelet cytoskeleton.

Serum cardiac troponin T in patients with acute myocardial infarction. Detection of coronary reperfusion and prediction of cardiac function

Serum troponin T, a myocardial contractile protein, has been reported to be a sensitive marker for the diagnosis of acute myocardial infarction. However, there have been few reports on its ability to detect coronary reperfusion and to predict left ventricular function in the chronic stage. Twenty two patients (20 males and 2 females, 61 +/- 10 y.o.) with acute myocardial infarction were enrolled in this study. They were divided into 2 groups, one with successful reperfusion (group A: n = 13) and one without reperfusion (Group B: n = 9) and the serial changes of their serum troponin T levels were evaluated. Serum myosin light chain was measured in another group of patients with acute myocardial infarction without history of old myocardial infarction (group C: n = 8). The slope of the logarithm of serum troponin T on a time-value curve was calculated from the time of admission to the first peak within 24 hours of the onset of acute myocardial infarction. The correlation coefficient between the late peak of serum troponin T and the left ventricular ejection fraction in 11 patients with first Q wave acute myocardial infarction was compared with that between the serum myosin light chain peak and the left ventricular ejection fraction in group C. 1) The slope of the logarithm of serum troponin T on the time-value curve in group A was greater than that in group B (0.57 +/- 0.45 vs. 0.22 +/- 0.16) (p < 0.05). 2) There was a good correlation between the late peak level of serum troponin T (78 +/- 10 hours after the onset) and the left ventricular ejection fraction in 11 patients with first Q wave acute myocardial infarction (r = -0.84, p < 0.01), which was similar to that of the serum myosin light chain peak and the left ventricular ejection fraction (r = -0.72, p < 0.05). On the other hand, there was no correlation between the peak level of serum creatine phosphokinase and the left ventricular ejection fraction (r = -0.55, NS). The serum troponin T levels 24, 36, 48 and 60 hours after the onset also correlated well with the left ventricular ejection fraction (r = -0.65, -0.7, -0.65 and -0.89, respectively). We conclude that the serial measurement of serum troponin T in patients with acute myocardial infarction is useful in the evaluation of left ventricular function in the chronic stage and that it is a potential non-invasive predictor of coronary reperfusion.

Changes in serum myosin light chain I following aortocoronary bypass operations

The changes in myosin light chain I (MLC I) following aortocoronary bypass were studied in 31 patients and the curves of these changes were classified into three different patterns. A peak level of 14.7 +/- 1.54 ng/ml was seen in seven patients on postoperative day (POD) 2 which decreased suddenly to less than twice the normal value by POD 7 (group 1). Another 19 patients showed a peak level of 20.7 +/- 16.5 ng/ml on POD 5, which decreased slowly and was still high even by POD 7 (group 2). The remaining five patients developed only a slight increase in the MLC I level after the operation, with a peak value of 5.5 +/- 0.8 ng/ml (group 3). Creatine kinase myocardial band and glutamic oxaloacetic transaminase also remained low in this group. No correlation existed between the peak value of MLC I and the aortic cross-clamping time, or between the peak value of MLC I and the cardiopulmonary bypass time. Furthermore, the difference in cardiac output before and after the operation did not significantly differ among the three groups. These findings indicate that the measurement of MLC I is useful for diagnosing perioperative myocardial damage and may also be useful in the study of myocardial protection.

Myocardial infarct size by serum troponin T and myosin light chain 1 concentration

The late troponin T (TnT) peak concentration, which is known to be independent of reperfusion of the infarcted zone in acute myocardial infarction (MI), has been suggested to be correlated with clinical estimates of cardiac function and myocardial infarct size. To refine the clinical application of the late TnT peak in infarct sizing, and to examine differences in this estimation in different infarct sites, we measured the serum concentrations of TnT and myosin light chain 1 (MLC1), and compared these values with left ventricular ejection fraction (LVEF) obtained from left ventriculography, and extent score (ES) and severity score (SS) obtained from 201Tl scintigraphy in patients with anterior and inferior myocardial infarction. The late TnT peak concentration was strongly correlated with the MLC1 peak value in patients with anterior MI (r = 0.67, p < 0.05) and in those with inferior MI (r = 0.92, p < 0.0005). Furthermore, there were strong linear correlations between the late TnT peak values and all of the clinical data (LVEF; r = -0.79, p < 0.01, ES; r = 0.75, p < 0.05, SS; r = 0.75, p < 0.05, respectively) in patients with anterior MI. However, these correlations were weak in patients with inferior MI. Similar correlations were observed between MLC1 and the clinical data. Thus, TnT and MLC1 have similar kinetics in the serum at the late phase and can be used to estimate the size of anterior infarct.

Independent prognostic value of serum creatine kinase isoenzyme MB mass, cardiac troponin T and myosin light chain levels in suspected acute myocardial infarction. Analysis of 28 months of follow-up in 196 patients

OBJECTIVES

We sought to determine the incidence and independent prognostic value of increased serum levels of sensitive serologic markers in patients in whom a conventionally diagnosed acute myocardial infarction had been ruled out.

BACKGROUND

Increased serum levels of creatine kinase (CK) isoenzyme MB mass and cardiac troponin T in patients with unstable angina pectoris are associated with a poor prognosis.

METHODS

We analyzed data from 196 consecutive patients with suspected acute myocardial infarction, which was later ruled out in 124. Increased serum levels of CK-MB mass, troponin T and myosin light chains were compared with clinical findings, ST-T wave abnormalities and presence of arrhythmias.

RESULTS

Of the patients in the noninfarction group, 28% had serum CK-MB mass > or = 6 micrograms/liter, 20% had troponin T > or = 0.20 micrograms/liter, and 26% had myosin light chains > or = 0.4 micrograms/liter (discrimination limits). The cardiac event rate (cardiac death, nonfatal acute myocardial infarction) within 28 months was significantly higher in patients in the noninfarction group with elevated marker levels (range 22% to 24%) than in patients with values below these discriminators (range 3% to 5%) but was not significantly different from that in patients with a definite diagnosis of acute myocardial infarction (29%). Further, significant predictors of cardiac events were previous myocardial infarction; myocardial infarction or angina pectoris, or both; previous congestive heart failure; ST-T wave abnormalities on admission; a transient ST-T wave shift on serial electrocardiograms (ECGs); recurrent chest pain; and occurrence of supraventricular or ventricular tachycardia, or both, during the 1st 48 h after admission. It was found that all three biochemical markers, in the main, convey independent prognostic information with respect to clinical findings and presence of arrhythmias but not ST-T wave abnormalities on admission or a transient ST-T wave shift on serial ECGs.

CONCLUSIONS

Increased serum levels of CK-MB mass, troponin T and myosin light chains all detect a subgroup of 25% of patients without acute myocardial infarction who have as poor a prognosis as that of patients with a definite diagnosis of acute myocardial infarction. All three biochemical markers provide similar important independent prognostic information with regard to clinical findings and arrhythmias but add no additional prognostic information once ECG ST-T wave changes are considered.

Augmented expression of atrial myosin light chain 1 in ventricular aneurysms of human: enzyme immunoassay for atrial myosin light chain 1

We established an enzyme immunoassay (EIA) for atrial myosin light chain 1 (ALC1) using monoclonal antibodies KA1 and KB1, which were specific for ALC1 and for both ALC1 and ventricular myosin light chain 1, respectively. The serum ALC1 levels of healthy subjects were 0.28 +/- 0.14 ng/ml (mean +/- SD). The tissue ALC1 levels of normal adult human atria were much higher than those of ventricles (p < 0.01, 2,120 +/- 1,200 in right atria, 2,180 +/- 1,450 in left atria vs. 36.0 +/- 20.2 in right ventricles, 37.7 +/- 15.3 in left ventricles, ng/mg of proteins). The tissue ALC1 levels of ventricular aneurysms were significantly higher than those of normal ventricles (p < 0.01, 206.7 +/- 101.8). These results indicate that ALC1 is augmented in aneurysms and that the EIA provides a useful tool to investigate the roles of ALC1.

Discordance between results for serum troponin T and troponin I in renal disease

Two patients were investigated for unexplained increases in troponin T. In the first patient, who had rhabdomyolysis and acute renal failure, troponin T reached a peak value of 13.50 micrograms/L (67.5-fold the upper reference limit). The second patient had chronic renal failure and the troponin T peak value was 2.85 micrograms/L (14.3-fold the upper reference limit). Clinical investigations indicated no evidence of myocardial damage. Serum or plasma specimens were analyzed for total creatine kinase (CK), CK-2 mass, CK-2 isoform ratio, myoglobin, troponin T, troponin I, and myosin light chains; all except troponin I were at above-normal concentrations. We also investigated six additional renal patients with above-normal troponin T; troponin I was slightly increased in only one of these six patients. Our findings demonstrate discordance between results for troponin T and troponin I in renal patients.

Normal post-race antimyosin myocardial scintigraphy in asymptomatic marathon runners with elevated serum creatine kinase MB isoenzyme and troponin T levels. Evidence against silent myocardial cell necrosis

Recent epidemiologic studies confirm that heavy physical exertion can trigger myocardial infarction. Diagnosis of acute myocardial injury in marathon runners is complicated by elevations of serum creatine kinase MB isoenzyme activity in asymptomatic finishers with normal post-race infarct-avid myocardial scintigraphy. Such isoenzyme elevations can arise from exertional rhabdomyolysis of skeletal muscle biochemically altered by training, from silent injury to the myocardium or from a combined tissue source. To assess silent myocardial cell necrosis in marathon runners, we performed quantitative anti-myosin myocardial scintigraphy after competition with serum immunoassays for creatine kinase MB isoenzyme and troponin T. Therefore, 8 male marathon runners with a mean age of 52 years underwent quantitative antimyosin myocardial scintigraphy immediately following the 1988 and 1993 Boston Marathons. Serum immunoassays for creatine kinase MB isoenzyme by a chemiluminescent method (CLIA) and troponin T by an enzyme-linked immunosorbent assay were performed in 4 runners after the 1993 race. Quantitative antimyosin myocardial scintigraphy was normal in all runners including 3 who participated after both races 5 years apart. Post-race serum creatine kinase MB isoenzyme and/or troponin T levels were in a range otherwise diagnostic of acute myocardial infarction in 3 of 4 subjects. Normal quantitative antimyosin myocardial imaging in asymptomatic marathon runners excludes silent myocardial cell necrosis as the source of elevated serum protein markers. Such imaging may be the optimal diagnostic modality for detection of myocardial cell necrosis in symptomatic athletes when results of conventional testing are inconclusive.

Inflammatory myopathy--early diagnosis and management by serum myosin light chains measurements

The use of serum myosin light chain 1 (MLC1) in the diagnosis and treatment response of a patient with biopsy proven inflammatory myopathy is presented. A serum MLC1 level was elevated at presentation despite a normal creatine phosphokinase level. MLC1 levels more closely paralleled the clinical status than the aspartate aminotransferase and lactate dehydrogenase levels. The results suggest that MLC1 levels may facilitate the early diagnosis and management of patients with inflammatory myopathy. Moreover, the excellent response of our patient to low dose prednisone might suggest that the results of treatment could be improved by early detection and institution of therapy.

Concentration time courses of troponin and myosin subunits after acute myocardial infarction

BACKGROUND

As a result of the limited sensitivity and specificity of creatine kinase and lactate dehydrogenase (LDH) as well as their isoenzymes, there is increasing interest in the use of cardiac contractile proteins for the diagnosis of acute myocardial infarction (AMI) and myocardial damage.

METHODS

This study compared the release of creatine kinase, creatine kinase MB, myoglobin, cardiac troponin I (cTnI), cardiac troponin T (cTnT), cardiac myosin light chain-1 (cMLC-1), and beta-type myosin heavy chains (bMHC) in serial blood samples from 13 patients (10 men, three women; median age 54 years, range 40-74 years) with first-time AMI (11 Q-wave, two non-Q-wave AMI; three anterior and 10 inferior wall AMI). All but one patient received intravenous thrombolytic treatment.

RESULTS

Myoglobin was the first marker to increase in blood after AMI and showed the earliest peak levels, whereas bMHC increased latest, showing the latest peak levels. cTnI and cTnT increased significantly earlier than cMLC-1 and bMHC. cTnI and cTnT increased and reached peak levels parallel to each other, but the latter tended to stay increased longer. cTnT time courses were biphasic in the majority of AMI patients, unlike cTnI time courses. cMLC-1 release was mostly biphasic. cMLC-1 allows diagnosis during the acute phase as well as several days after the onset of AMI. The time courses of bMHC were usually monophasic. Its delayed appearance makes it useful for the diagnosis of remote infarction. In contrast to cTnI and cTnT, cMLC-1 and bMHC time courses were not significantly influenced by early reperfusion.

CONCLUSION

Our results demonstrate the impact of the intracellular compartmentation of an intramyocardial protein (cytosolic, structurally bound, or structurally bound with soluble pool) on its concentration time course after AMI, particularly on the rapidity of its release.

Measurement of cardiac troponin T and myosin to detect perioperative myocardial damage during coronary surgery

This study evaluated the use of monitoring blood levels of the isoenzyme of creatine phosphokinase, troponin T (tnT) and myosin in the detection of perioperative myocardial damage after coronary artery surgery. Serial blood samples were collected in 24 patients undergoing myocardial revascularization. The patients were retrospectively divided into three groups: group A with no changes in their electrocardiogram; group B showing non-specific signs of perioperative myocardial infarction such as deep and permanent T wave inversion; and group C with definite electrocardiographic signs of perioperative myocardial infarction (new persistent Q-waves and loss of R-waves). Group A (n = 17) demonstrated a mean(s.d.) troponin T peak blood level of 0.64(0.35) ng/ml at 12-24 h after surgery, a myosin peak of 1030(670) mu units/l at 3-6 days afterwards, and a creatine phosphokinase isoenzyme peak of 25.8(10.6) units/l. In group B (n = 5), mean(s.d.) troponin T levels were elevated to a peak of 4.8(3.9) ng/ml 24 h after intervention, while myosin rose to 2074(340) mu units/l 3-6 days after surgery and creatine phosphokinase isoenzyme reached 57.8(38) units/l. Group C (n = 2) had a mean(s.d.) troponin T peak of 4.8(2.6) ng/ml, a myosin peak of 2404(392) mu unit/l and a creatine phosphokinase isoenzyme peak of 88.5(20) units/l. Peak values of troponin T and myosin in groups B and C were statistically different from those in group A (P < 0.001). These results suggest that troponin T and myosin are reliable indicators of perioperative myocardial damage. In particular, troponin T may allow the differentiation of reversible from irreversible myocardial injury.

Measurement of myosin light chain I and troponin T as markers of myocardial damage after cardiac surgery

The purpose of the study was to test cardiac myosin light chain I (CMLCI) and troponin T (TNT) as markers on myocardial damage after heart surgery. Forty-three patients undergoing cardiac surgery were arbitrarily divided into two groups according to creatine kinase MB isoenzyme (CK-MB) levels and postoperative electrocardiogram (ECG) changes. Group 1: CK-MB > 100 micrograms/L or ECG changes (extensive myocardial damage, 42%); Group 2: CK-MB < 100 micrograms/L and no ECG changes (minimal myocardial damage, 58%). Group 1 was divided into 2 groups (Infarction and Injury groups). CMLCI levels showed strong correlations with TNT levels after the operation. The peak CMLCI and TNT levels in group 1 were significantly higher than in group 2. The peak CMLCI in the Infarction group was significantly higher than in the Injury group. TNT showed different patterns in the Infarction and Injury groups. This study showed that CMLCI and TNT estimation could evaluate myocardial damage over several postoperative days. TNT estimation could identify myocardial damage earlier than CMLCI, however CMLCI could discriminate perioperative infarction better than TNT.

Assessment of myocardial damage by circulating cardiac myosin light chain I after heart transplantation

The purpose of this study was to evaluate the cardiac damage by cardiac myosin light chain I after transplantation. This study included 30 patients who underwent cardiac operations and who were divided into three groups. These groups consisted of (1) control group, 15 valvular patients without coronary disease (no electrocardiography changes and creatine kinase MB isoenzyme of 100 micrograms/L or less); (2) infarction group, eight patients (six coronary bypass and two valvular patients with perioperative infarction pattern in the electrocardiography and creatine kinase MB isoenzyme of 100 micrograms/L or more; and (3) transplantation group, seven transplant patients (six heart and one heart-lung). The peak cardiac myosin light chain I value in the transplantation group (32.9 +/- 3.4 micrograms/L) was comparable to the infarction group (27.6 +/- 2.6 micrograms/L), and both of them were significantly higher than the control group (9.2 +/- 0.9 micrograms/L) (p < 0.01). Peak cardiac myosin light chain I levels in the control and transplantation groups correlated with the ischemic time (r = 0.48, p < 0.05 and r = 0.67, p < 0.05, respectively). The total dose of dopamine in the transplantation group correlated with the peak cardiac myosin light chain I (r = 0.67, p < 0.05), and with the cardiac myosin light chain I value on day 7 (r = 0.88, p < 0.01). This study suggests that circulating cardiac myosin light chain I estimations are useful to evaluate myocardial damage after transplantation during postoperative week 1.

Relationship between the degree of injury at operation and the change in antimyosin antibody titer in the postpericardiotomy syndrome

Successive measurements of cardiac myosin light chain I (MLC), creatine kinase isoenzyme MB (CKMB), and the titer of antimyosin antibody (AMA) were performed prospectively in 19 patients following open heart surgery. Seven of these patients showed the postpericardiotomy syndrome (PPS). No differences in serum concentrations of MLC or CKMB were observed between the patients with and without PPS, and all patients in both groups had abnormal MLC values after surgery. However, only patients with PPS had significantly elevated AMA titers. The maximum AMA titer was significantly correlated with the severity of the effusion. These data suggest that PPS is unrelated to the severity of myocardial injury during operation. Furthermore, the AMA titer may be useful as one of the indicators for determining the patient's clinical condition.

[Significance of serum myosin light chain-1 level in neuroleptic malignant syndrome]

In Parkinson disease, the interruption of medication often results in neuroleptic malignant syndrome, which is caused by acute inhibition of the dopaminergic system. It is a serious question in the management of Parkinson disease, whether episode of pyrexia is derived from neuroleptic malignant syndrome or other origins. In this syndrome, muscle damage enhances serum titers of myogenic enzymes and proteins. Myosin light chain-1 (MLC-1), which is a small fragment of myosin, has been reported to show long lasting elevation compared with CK in neuromuscular diseases and cardiac infarction. Then, we evaluated the clinical significance of serum MLC-1 in six patients with neuroleptic malignant syndrome, i.e., four cases of Parkinson disease, one multiple system atrophy and one schizophrenia with acute administration of haloperidol. Muscle breakdown was observed by the elevation of serum MLC-1 titer, which sustained several days after normalization of serum CK titer. In two cases of Parkinson disease, high level of serum MLC-1 was observed in spite of normal body temperature, which suggested pre-clinical stage of neuroleptic malignant syndrome. Thus, we concluded that the estimation of serum MLC-1 is useful in those patients with high risk of neuroleptic malignant syndrome.

Okadaic acid induces marked shape change of human platelets

Okadaic acid (OA) induced marked shape changes of human platelets but neither granule secretion nor increase in [Ca2+]i occurred. Morphological changes induced by OA were unique and different from those observed with thrombin mainly in two respects. One is that the pseudopods formed by OA treatment were longer and straighter than those by thrombin. The other is that no granule centralization was observed with OA-treatment, although central condensation of cytofilaments was observed as was with thrombin. The immunocytochemical analysis employing anti-myosin antibody revealed that myosin was distributed in the elongated pseudopods. Since OA induced phosphorylation of the 20-kDa myosin light chain (MLC20) corresponding to the change in shape of platelets but did not induce phosphorylation of the 47-kDa protein (pleckstrin) (Higashihara M. et al. FEBS Lett. 307:206-210, 1992), these results suggest that phosphorylation of MLC20 plays an important role in OA-induced unique morphological changes of platelets.

[Relationship between early peaking of serum myosin light chain 1 level and washout phenomenon of creatine kinase in acute myocardial infarction]

To investigate the serum levels of myosin light chain 1 (MLC1) during the acute phase of myocardial infarction, the MLC1 and creatine kinase (CK) levels were measured in samples from 59 consecutive patients with acute myocardial infarction. The serum concentration of MLC1 increased rapidly, reaching an early peak in 22 of the 59 patients (the MLP + group). Fifteen patients showed rapid increases in MLC1 levels without an early peak (the MLP - group). Serum MLC1 levels remained within normal limits (the MLN group) 10 hours after the onset of symptoms in the remaining 22 patients (but in eight of these serum MLC1 levels were abnormal 16-39 hours after the onset of symptoms). Serum level curves of CK showed a single episode of acute myocardial infarction in all patients. The patterns of MLC1 levels correlated with the washout phenomenon of CK (p < 0.001) and the maximum MLC1 level (p < 0.05). The ratio of serum MLC1 level during the early phase to the maximum level (EMR) decreased in the order of groups MLP+, MLP-, MLN (0.54 +/- 0.28, 0.31 +/- 0.22, 0.13 +/- 0.09, respectively). The EMR was correlated with the washout phenomenon of CK (p < 0.001), but not with the maximum MLC1 level which might reflect the size of the infarction. The patterns of neither MLC1 nor EMR were correlated with the administration of urokinase or the patency of the infarct-related artery at the early phase (within 10 hours of onset).(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced activity of serum creatine kinase in rheumatoid arthritis: a phenomenon linked to the inflammatory response

In a case-controlled study, serum creatinine kinase (CK) activity was significantly lower in 40 patients with RA than in 40 age- and sex-matched patients with non-inflammatory arthropathies [mean 37.6 (S.D. 29.2) vs 77.7 (S.D. 45.3) IU/l respectively P < 0.0001]. In contrast, serum levels of aldolase and myosin were not significantly lower in RA patients. A significant inverse correlation between CK activity and ESR, CRP and platelet count was observed in RA. There was also a positive correlation between haemoglobin levels and CK values. No correlation was found between CK activity and a meager mass index, disease duration and radiological erosion. No inhibitor of CK activity in the sera of RA patients was found. CK serum activity was markedly reduced in RA, and is related to the inflammatory activity of the disease. This finding may stimulate further exploration on the effect of inflammatory response in muscle metabolism.

Human ventricular myosin light chain isotype 1 as a marker of myocardial injury

A monoclonal enzyme immunoassay for measuring human ventricular myosin light chain isotype 1 (HVMLC1) in serum has been developed. To evaluate the method in patients with suspected myocardial injury, we studied 51 patients (16 acute myocardial infarction (AMI), 19 unstable angina pectoris (UAP), 9 stable angina pectoris, 3 nonischemic heart disease, 4 hip surgery patients), and 190 controls (blood donors). Serial blood-samples were drawn from patients; a single blood-sample from controls. The diagnostic value of the HVMLC1 assay was compared with total creatine kinase (CK), CKMB activity, CKMB mass concentration, lactate dehydrogenase isoenzyme 1 (LD1), troponin T (TnT) and mitochondrial-aspartate aminotransferase (m-ASAT). The detection limit of HVMLC1 was 0.4 microgram/l (linear range 0-20 micrograms/l). Sera from 190 reference persons did not contain detectable levels of HVMLC1 (< 0.4 microgram/l; 99% percentile). The coefficients of variation were 13% (1.0 microgram/l) and 3.1% (17.7 micrograms/l). Cross-reactivity with myosin from skeletal muscle was seen. Times to peak value were: CK 19.3 +/- 2.0, LD1 43.4 +/- 3.2, HVMLC1 72.9 +/- 7.0, and m-ASAT 67.3 +/- 5.6 h. Time-curves of HVMLC1 and m-ASAT were similar, whereas time-curves for HVMLC1 and TnT were quite different in most cases. Peak value of HVMLC1 was five times higher than CK peak value and eight times that of LD1. HVMLC1 appeared in the blood within hours after the onset of chest pain and in the majority remained for more than a week after AMI. Among patients with UAP 16% (3/19) had elevated HVMLC1 in serum, whereas elevated TnT was seen in 26% (5/19) and elevated CKMB mass in 26% (5/19). We conclude that the new HVMLC1 assay offers a sensitive diagnosis of myocardial injury. It is characterized by a wide diagnostic time window. The similarity of the HVMLC1 and m-ASAT curves indicates that it may be used to estimate the extent of myocardial necrosis.

Detection of perioperative myocardial structural damage by the estimation of cardiac myosin light chain I

The accurate estimation of myocardial damage is desirable for the assessment of myocardial protection and surgical treatments. The purpose of the study was to estimate myocardial damage by measuring cardiac myosin light chain I (CMLCI). Forty-nine patients undergoing cardiac surgery (for angina or valvular disease) were arbitrarily divided into four groups according to the maximum CMLCI level. Group 1: max CMLCI < 10 micrograms/L (37%); Group 2: max CMLCI 10-20 micrograms/L (39%); Group 3: max CMLCI 20-30 micrograms/L (16%); Group 4: max CMLCI > 30 micrograms/L (8%). Electrocardiogram (ECG) and serum creatine kinase MB isoenzyme (CK-MB) were conventionally used as standards of myocardial damage, and compared with CMLCI. Perioperative myocardial infarction, injury and minimum damage were determined by combinations of ECG pattern changes and CK-MB levels. The max CMLCI level was usually seen on the third postoperative day. None of the patients in group 1 had any ECG changes. The number of patients with ECG changes was much higher as the max CMLCI level increased, and evidently increased when the max CMLCI was over 20 micrograms/L. The number of patients with high CK-MB > 100 micrograms/L followed the same pattern. Furthermore, perioperative infarction was only seen when the max CMLCI was > 30 micrograms/L. The peak CMLCI level was significantly higher in the infarction group than injury and minimum damage groups. This study showed that CMLCI was able to estimate the actual extent and severity of the myocardial damage and enhanced the diagnosis of perioperative infarction.

Role of myosin light-chain phosphorylation in endothelial cell retraction

Endothelial cells retract centripetally when they are exposed to histamine and when extracellular calcium is chelated. This centripetal retraction implies that a centripetal tension must be expressed in the cells. We asked whether phosphorylation of the light chain of myosin (MLC) was important for the retraction to occur, and, by inference, expression of the tension. In human umbilical vein endothelial (HUVE) cells and in porcine pulmonary artery endothelial (PPAE) cells tryptic peptide maps indicated that MLC was phosphorylated by myosin light-chain kinase (MLCK). Activity of MLCK is inhibited by ML-9, a kinase inhibitor with relative specificity for MLCK, and when MLCK is phosphorylated by the adenosine 3',5'-cyclic monophosphate (cAMP)-dependent kinase. Pretreatment of HUVE cells or PPAE cells with ML-9 or forskolin-aminophylline (to increase cell cAMP) reduced basal MLC phosphorylation and prevented an expected increase in MLC phosphorylation following exposure of HUVE cells to histamine. Pretreatment of HUVE cells with ML-9 or forskolin-aminophylline prevented HUVE cell retraction (measured as an increase in permeability of a monolayer of HUVE cells) in response to histamine. Pretreatment of PPAE cells with ML-9 or forskolin-aminophylline prevented PPAE cell retraction in response to chelation of extracellular calcium. These data support the hypothesis that phosphorylation of MLC is an important component of endothelial cell retraction.

Modulation of the cytoskeleton and intracellular calcium in leukocytes exhibiting a cancer-associated chemotaxis defect

Monocyte chemotaxis is severely depressed in patients with advanced tumors, but the cellular basis for this chemotactic defect is not known. Because the actomyosin cytoskeleton is thought to play a primary role in chemotaxis, we have employed flow cytometry to examine several aspects of the contractile machinery including myosin II, myosin light chain kinase (MLCK), actin, and cytoplasmic calcium in unstimulated and in formylpeptide-stimulated neutrophils and monocytes. Serum-pretreated polymorphonuclear leukocytes (PMNs) and monocytes from healthy blood donors or PMNs and monocytes isolated from tumor patients were studied. Leukocytes pretreated with serum from cancer patients exhibited decreased baseline myosin staining and a vastly different response to formylpeptide stimulation compared with leukocytes pretreated with normal human serum. In contrast, similar amounts of MLCK were observed in neutrophils and monocytes preincubated with normal or cancer serum with or without stimulation with formylpeptide. The fluorescent calcium indicator fluo-3 showed that resting and fMLP-stimulated levels of intracellular calcium were not significantly different in control and cancer serum-pretreated human leukocytes or in leukocytes isolated from tumor patients. Similarly, resting and fMLP-stimulated levels of F-actin in cancer patients' leukocytes as assessed by NBD-phallacidin staining did not differ significantly from those of normal leukocytes. Because the actomyosin cytoskeleton is intricately involved in leukocyte chemotaxis, alterations in the cytoskeleton may dramatically affect cell motility. The cytoskeletal alterations and changes in the response of leukocytes pretreated with cancer patients' serum to formylpeptide stimulation as described here may result in decreased chemotaxis by these cells.

Myosin light chain efflux after heart transplantation in infants and children and its correlation with ischemic preservation time

Serum levels of cardiac myosin light chain 1 after heart transplantation were studied in 24 infants and children who underwent heart transplantation between June 1990 and April 1991. The ages of the patients ranged from 4 days to 6 years 7 months (mean, 9.9 months), and their body weights ranged from 2.2 to 20 kg (mean, 5.6 kg). The ages of the donors ranged from 2 days to 8 years, 7 months (mean, 26.6 months), and their body weights ranged from 2.5 to 26 kg (mean, 11.4 kg). The donor heart ischemic time ranged from 90 minutes to 482 minutes (mean, 279 minutes). Peak myosin levels after heart transplantation showed significant correlation with the duration of graft ischemia (p < 0.01) and with diastolic cardiac function in the first posttransplant week (p < 0.05). Peak myosin levels did not correlate with systolic cardiac function, age of the donor, or age of the recipient. Myosin levels of the 15 patients with graft ischemic times exceeding 4 hours averaged 6.30 +/- 3.50 ng/ml. These levels were significantly higher than those of patients with graft ischemia lasting less than 4 hours (2.60 +/- 1.20 ng/ml; p < 0.01). Both of the values are higher than previously reported values of normal controls but lower than previously reported values of patients with myocardial infarction. Preservation techniques used for this series of transplant operations provided good clinical protection of the donor heart for up to 8 hours, although release of the cardiac myosin light chain fragment correlated with duration of graft ischemia. Cardiac myosin levels appeared to be a good indicator of heart graft damage during ischemic preservation. It remains to be determined at what level of myosin release (and, hence, at what duration of graft ischemia) irreversible myocardial damage, which might result in permanent functional compromise, occurs.

[Myosin: a necrosis marker: update and trends]

Plasma myosin heavy chain fragments are a "quantitative indicator of myocardial necrosis" in patients with myocardial infarction. Myosin assay enables: retrospective diagnosis of necrosis; assessment of infarct size; evaluation of the scarring process and risk of recurrence; analysis of methods of cardioplegia in cardiac surgery by detection of perioperative infarction; determination of the long-term prognosis of post-infarct patients.

[Characteristics of plasma levels of myosin light chain I in patients under aorta-coronary bypass grafts]

After cardiac operation plasma level of ventricular myosin light chain I (LCI), determined with monoclonal antibodies to myosin fragment, were studied in 30 patients under bypass surgery to assess its possible role as a marker for perioperative myocardial injury. LCI rapidly increased and reached peak levels (15.8 +/- 9.0 gn/ml; T-peak) at 88 +/- 28 minutes after aortic declamp (T-Time). Then LCI rapidly decreased with fast half-time disappearance (1.1 +/- 0.7 hours). In 7 out of 30 patients LCI improved to normal range and MB reached maximum levels (28.8 +/- 11.9 U/L) at 6.3 +/- 2.3 hours after declamp. No abnormal change was noted in ECG and no new defects were noted in T1-201 myocardial images. In the remaining 23 patients LCI decreased to minimum levels (4.1 +/- 2.1 ng/ml; min-LCI) at 9.2 +/- 5 hours (min-Time) and then gradually increased to peak levels (8.4 +/- 5.8 ng/ml; M-peak, M-value) on day 3.3 +/- 1.0 (M-Time). MB reached maximum level (77.6 +/- 82.4 U/L, p < 0.1) at 3.4 +/- 1.4 hours (p < 0.001). Good correlation was noted among min-LCI, min-Time, M-value and summation of daily value of LCI (omega(LCI)) x min-LCI = 5.7-0.17 min-Time (r = -0.42) and M-value = 2.1 min-LCT(r=0.74) and omega(LCI) = -9.6 + 6.1 M-value (r = -0.96). From the rapid appearance of LCI peak levels after aortic declamp it was concluded that LCI, accumulated during aortic clamp, was washed out by aortic declamp.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoradiometric assay of serum myosin as a marker of myocardial cell damage: methodological and clinical evaluation

We evaluated the performance and analytical parameters of a one-step magnetic IRMA kit for the measurement of myosin in serum. The method uses two monoclonal antibodies selected for their high affinity to the heavy chains of human ventricular myosin. The first antibody is coupled to a magnetic solid phase and the second one is labeled with 125I. The working range of the IRMA (range of myosin concentrations measured with an imprecision < 10% CV) was 250-3600 microU/L and the sensitivity 20.8 +/- 7.2 microU/L. The between-assay variability, evaluated from replicate measurements in different runs of two serum pools was 14.6 CV% for the first pool (259.1 +/- 37.8 microU/L) and 14.3 CV% for the second pool (442.0 +/- 63.1 microU/L), respectively. To evaluate the clinical usefulness of myosin as a marker of myocardial cell damage, serum myosin was measured in patients with acute myocardial infarction (AMI) (n = 9) or subarachnoid hemorrhage (n = 20). The results obtained with the myosin assay were compared with those of two other markers considered specific for myocardial necrosis (CK-MB and myoglobin). In eight patients with AMI, serum myosin was elevated 24-36 hours after the onset of chest pain and reached a maximum at 4-7 days, returning to control levels at 8-11 days. The one remaining AMI patient showed two subsequent peaks in serum CK-MB and myoglobin concentrations (thus suggesting an extension of myocardial necrosis), the myosin concentrations reaching their peak only after 9 days.(ABSTRACT TRUNCATED AT 250 WORDS)