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Introduction: Myotoxicity is an important toxidrome that can occur with envenoming from multiple Australian snake types. Early antivenom administration is an important strategy to reduce the incidence and severity of myotoxicity. The current gold standard biomarker, serum creatine kinase activity, does not rise early enough to facilitate early antivenom administration. Several other skeletal muscle biomarkers have shown promise in other animal models and scenarios. The aim of this study was to examine the predictive values of six skeletal muscle biomarkers in a rat model of Australian snake myotoxicity., Methods: Sprague-Dawley rats were anaesthetised and administered either Pseudechis porphyriacus (red-bellied black snake) or Notechis scutatus (tiger snake) venom, or normal saline via intramuscular injection. Blood samples were collected. Assays were performed for serum creatine kinase skeletal muscle troponin-I concentration, skeletal muscle troponin-C concentration, myoglobin activity, skeletal muscle myosin light chain-1 concentration, and creatine kinase-MM activity. Serum markers were plotted against time, with comparison of area under the concentration (or activity)-time curve. The predictive values of six skeletal muscle biomarkers were examined using receiver operating characteristic curves., Results: There was no difference in area under the serum creatine kinase activity-time curve between venom and control groups. Serum creatine kinase-MM activity rose early in the venom treated rats, which had a significantly greater area under the serum activity-time curve. No difference in area under the serum concentration-time curve was demonstrated for the other biomarkers. Creatine kinase-MM activity had a superior predictive values than creatine kinase activity at 0-4 hours and 0-10 hours after venom administration, as indicated by area under the receiver operating characteristic curves (95 per cent confidence intervals) of 0.91 (0.78-1.00) and 0.88 (0.73-1.00) versus 0.79 (0.63-0.95) and 0.66 (0.51-0.80)., Discussion: The limitations of serum creatine kinase activity in early detection of myotoxicity were demonstrated in this rat model., Conclusion: Serum creatine kinase-MM activity was superior for early detection of Australian myotoxic snake envenoming.

The mortality of coronavirus disease 2019 (COVID-19) is strongly correlated with pulmonary vascular pathology accompanied by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-triggered immune dysregulation and aberrant activation of platelets. We combined histological analyses using field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy analyses of the lungs from autopsy samples and single-cell RNA sequencing of peripheral blood mononuclear cells to investigate the pathogenesis of vasculitis and immunothrombosis in COVID-19. We found that SARS-CoV-2 accumulated in the pulmonary vessels, causing exudative vasculitis accompanied by the emergence of thrombospondin-1-expressing noncanonical monocytes and the formation of myosin light chain 9 (Myl9)-containing microthrombi in the lung of COVID-19 patients with fatal disease. The amount of plasma Myl9 in COVID-19 was correlated with the clinical severity, and measuring plasma Myl9 together with other markers allowed us to predict the severity of the disease more accurately. This study provides detailed insight into the pathogenesis of vasculitis and immunothrombosis, which may lead to optimal medical treatment for COVID-19.

Objective: To analyze the predictive value of serum microRNA-106 (miRNA-106), miR-106, and myosin light chain 4 (MYL4) levels on the prevalence of atrial fibrillation and to explore the relationship between serum miR-106 and MYL4 and the risk stratification and prognosis of atrial fibrillation, thereby providing basis for them to become clinical targets for the treatment of atrial fibrillation in the future., Methods: 300 patients with atrial fibrillation treated in our hospital from May 2017 to March 2019 were selected as the atrial fibrillation group, and 300 healthy people who came to our hospital for physical examination in the same period were selected as the control group. The general data of the subjects in the two groups were collected. The serum miR-106 level of the subjects in the two groups was detected by fluorescence quantitative polymerase chain reaction (PCR), and the level of MYL4 was detected by enzyme-linked immunosorbent assay (ELISA). The expression of miR-106 and MYL4 in the myocardium was observed by immunohistochemistry. The relationship between the levels of serum miR-106 and MYL4 and the prevalence of atrial fibrillation and the score of atrial fibrillation thromboembolism risk stratification scoring system (cha2ds2) was compared between the two groups. The relationship between serum level of miR-106 and prognosis of patients with atrial fibrillation was analyzed., Results: The systolic blood pressure, diastolic blood pressure, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and left anterior descending artery (LAD) in the atrial fibrillation group were significantly higher than those in the control group, while HDL-C and left ventricular ejection fraction (LVEF) were significantly lower than those in the control group ( P < 0.01). The level of serum miR-106 in patients with atrial fibrillation was significantly higher than that in the control group, whereas the level of MYL4 was significantly lower than that in the control group ( P < 0.01). miR-106 was mainly localized in the cytoplasm, and the positive expression rate of miR-106 was 71.43% (81/115) in patients with atrial fibrillation and 21.74% (25/115) in patients with sinus rhythm. MYL4 was mainly located in the cell membrane and the positive expression rate of MYL4 was 24.35% (28/115) in patients with atrial fibrillation and 64.35% (74/115) in patients with sinus rhythm. With the increase of the severity of atrial fibrillation, the level of serum miR-106 gradually increased and the level of MYL4 gradually decreased, which were statistically significant compared with the control group ( P < 0.05). With the increase of miR-106 level and the decrease of MYL4 level, the prevalence of atrial fibrillation gradually increased. With the increase of cha2ds2 score, the level of serum miR-106 increased and the level of MYL4 decreased. The survival rate of patients with miR - 106 ≤ 1.96 was significantly higher than that of patients with miR - 106 > 1.96. The survival rate of patients with MYL4 ≥ 0.24 was significantly higher than that of patients with MYL4 < 0.24. At the same time, TC and LDL-C were included in the analysis. The results showed that the survival rate of patients with TC ≤ 4.5 mmol/L was significantly higher than that of patients with TC > 4.5 mmol/L, and that of patients with LDL-C ≤ 2.6 mmol/L was significantly higher than that of patients with LDL-C > 2.6 mmol/L., Conclusion: Serum miR-106 and MYL4 levels are closely related to the prevalence of atrial fibrillation, which can reflect the risk of thromboembolism in patients with atrial fibrillation and can be used as a biological indicator to predict the prognosis of patients with atrial fibrillation., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © 2022 Yanfeng Liu et al.)

Background: Idiopathic pulmonary fibrosis (IPF) has high mortality worldwide. The CD247 molecule (CD247, as known as T-cell surface glycoprotein CD3 zeta chain) has been reported as a susceptibility locus in systemic sclerosis, but its correlation with IPF remains unclear., Methods: Datasets were acquired by researching the Gene Expression Omnibus (GEO). CD247 was identified as the hub gene associated with percent predicted diffusion capacity of the lung for carbon monoxide (Dlco% predicted) and prognosis according to Pearson correlation, logistic regression, and survival analysis., Results: CD247 is significantly downregulated in patients with IPF compared with controls in both blood and lung tissue samples. Moreover, CD247 is significantly positively associated with Dlco% predicted in blood and lung tissue samples. Patients with low-expression CD247 had shorter transplant-free survival (TFS) time and more composite end-point events (CEP, death, or decline in FVC >10% over a 6-month period) compared with patients with high-expression CD247 (blood). Moreover, in the follow-up 1st, 3rd, 6th, and 12th months, low expression of CD247 was still the risk factor of CEP in the GSE93606 dataset (blood). Thirteen genes were found to interact with CD247 according to the protein-protein interaction network, and the 14 genes including CD247 were associated with the functions of T cells and natural killer (NK) cells such as PD-L1 expression and PD-1 checkpoint pathway and NK cell-mediated cytotoxicity. Furthermore, we also found that a low expression of CD247 might be associated with a lower activity of TIL (tumor-infiltrating lymphocytes), checkpoint, and cytolytic activity and a higher activity of macrophages and neutrophils., Conclusion: These results imply that CD247 may be a potential T cell-derived disease severity and prognostic biomarker for IPF., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Li, Chen, Li, Wang, Li, Ning and Chen.)

Background: The vascular component of the hand-arm-vibration syndrome (HAVS) is often characterized by vibration-induced white fingers (VWF). Active substances secreted by the vascular endothelial cells (VEC) maintain a dynamic balance but damage to the blood vessels may occur when the equilibrium is altered, thus forming an important pathological basis for VWF. This study was aimed at investigating vascular damage indicators as a basis for an early detection of disorders caused by vibration, using the rat tail model., Methods and Results: Experiments were conducted using a control group of rats not exposed to vibration while two exposed groups having different exposure durations of 7 and 14 days were randomly formed. Following exposure, the structural changes of tail tissue samples in anesthetized rats were observed. Enzyme-linked immunosorbent assay (ELISA) was used for analyzing four vascular damage indicators myosin regulatory light chain (MLC2), endothelin-1 (ET-1), vinculin (VCL) and 5-hydroxytryptamine (5-HT) in tail blood samples. We found that both vascular smooth muscle and endothelial cells displayed changes in morphology characterized by vacuolization and swelling in the vibration-exposed group. The levels of vascular damage indicators were altered under the vibration., Conclusion: The degree of vascular pathology increased with the longer duration exposure. Furthermore, the levels of MLC2, ET-1 and 5-HT in rat plasma were associated with vascular injury caused by local vibration., (Copyright © 2021. Published by Elsevier Inc.)

Objective: In this clinical case-control study, we investigated statin treatment in stroke patients on a range of inflammatory effectors in peripheral blood. We focus on RhoA GTPase and its downstream effectors as a future inflammatory target in stroke treatment., Methods: Data from 10 patients already on statins at stroke onset (Pre-S group) was compared with data from both 29 patients starting statin treatment right after stroke onset (Post-S group) and with 8 healthy controls. In T-cells isolated from stroke patients, we analyzed the activity of the main cytoskeletal regulator RhoA GTPase and its downstream effectors: rho-associated protein kinase (ROCK), myosin phosphatase targeting protein subunit 1 (pMYPT1), myosin light chain kinase (pMLC) and cofilin. In the blood samples, we further determined levels of 12 key plasma cytokines as well as C-reactive protein (CRP) and kallikrein., Results: Compared to healthy controls, the Post-S group achieved significantly higher RhoA and ROCK activities, while the Pre-S did not differ from controls. Levels of pMYPT1, pMLC and cofilin did not differ from controls in the Pre-S and Post-S groups. At day 90 after stroke, interferon γ and IL-18 were significantly increased in the Post-S group compared to the Pre-S group. We found a positive correlation between CRP and NIHSS, whereas kallikrein levels showed no correlation with NIHSS at any of the days., Conclusion: Stroke induces changes in the RhoA-ROCK pathway in T-cells. CRP and NIHSS score correlated positively in the study. Statins may have an anti-inflammatory effect as statin treatment before stroke reduces post-stroke pro-inflammatory levels. RhoA GTPase and its downstream effectors are possibly the key to improve statin treatment in stroke.

Introduction: Reticulated platelet (RP) content is increased in nonvalvular atrial fibrillation (NVAF). The purpose of this study was to determine if platelet content, morphology, and RP proportion are modulated by platelet genes., Methods and Results: Expression of six platelet-predominate genes impacting platelet formation and release, platelet count, and RP content was assessed in NVAF patients before and 3-4 months after pulmonary veins isolation (PVI) and compared to normal sinus rhythm (NSR) controls. RNA from isolated platelets was reverse-transcribed assayed against selected genes utilizing real-time qPCR, and expressed as mean cycle threshold (ΔCt) using beta-2-microglobulin as endogenous control. RP content was assessed by flow cytometry. A fourfold lower expression of CFL1 gene coding for nonmuscle cofilin (7.8 ± 0.9 vs. 5.7 ± 1.6, P < 0.001) and twofold lower expression of four other genes were associated with similar platelet counts but fourfold higher (28.7+7.0 vs. 6.7+5.4, P < 0.001) RP content (%) in 97 NVAF cases compared to 51 NSR controls. Three to 4 months after PVI, RP decreased by 28%, while CFL1 gene expression increased over twofold but TUBA4A gene expression decreased almost twofold; NFE2 and MYL6 gene expression remained unchanged., Conclusions: NVAF is associated with notable downregulation of genes directing platelet production and size but increased RP content. PVI impacts the expression of many of these genes, implying a direct relationship between atrial fibrillation and platelet biogenesis., (© 2018 Wiley Periodicals, Inc.)

Objective: To investigate the changes in serum cardiac myosin light chain 1 (CMLC-1) levels in children with fulminant myocarditis (FM) during continuous blood purification (CBP), as well as to analyze its correlation with other laboratory indexes., Method: Twenty-four (24) children with FM who underwent CBP were enrolled. Before and during treatment (48 and 72 hours after treatment, or death), the optical density value of serum CMLC-1 was measured using enzyme-linked immunosorbent assay, and then the serum CMLC-1 concentration was calculated. The correlations between CMLC-1 OD value change and laboratory indexes including creatine kinase-MB (CK-MB), troponin, myohemoglobin and N-terminal pro-brain natriuretic peptide (NT-proBNP) were analyzed., Results: The serum CMLC-1 concentration significantly increased in the children with FM and decreased obviously during CBP therapy. In the same period, the change of CMLC-1 concentration were positively correlated with creatine kinase-MB (r=0.528), troponin (r=0.726), myohemoglobin (r=0.702), and NT-proBNP levels (r=0.589)., Conclusion: The serum CMLC-1 concentration increases significantly in children with FM, but CBP therapy can effectively control this increase.

Clofibrate is a known rodent hepatotoxicant classically associated with hepatocellular hypertrophy and increased serum activities of cellular alanine aminotransferase/aspartate aminotransferase (ALT/AST) in the absence of microscopic hepatocellular degeneration. At toxic dose, clofibrate induces liver and skeletal muscle injury. The objective of this study was to assess novel liver and skeletal muscle biomarkers following clofibrate administration in Wistar rats at different dose levels for 7 days. In addition to classical biomarkers, liver injury was assessed by cytokeratin 18 (CK18) cleaved form, high-mobility group box 1, arginase 1 (ARG1), microRNA 122 (miR-122), and glutamate dehydrogenase. Skeletal muscle injury was evaluated with fatty acid binding protein 3 (Fabp3) and myosin light chain 3 (Myl3). Clofibrate-induced hepatocellular hypertrophy and skeletal muscle degeneration (type I rich muscles) were noted microscopically. CK, Fabp3, and Myl3 elevations correlated to myofiber degeneration. Fabp3 and Myl3 outperformed CK for detection of myofiber degeneration of minimal severity. miR-122 and ARG1 results were significantly correlated and indicated the absence of liver toxicity at low doses of clofibrate, despite increased ALT/AST activities. Moreover, combining classical and novel biomarkers (Fabp3, Myl3, ARG1, and miR-122) can be considered a valuable strategy for differentiating increased transaminases due to liver toxicity from skeletal muscle toxicity.

The skeletal muscle (SKM) injury biomarkers, skeletal troponin I (sTnI), myosin light chain 3 (Myl3), and creatine kinase muscle isoform (Ckm) have been shown recently to be more sensitive and specific for monitoring drug-induced SKM injury than the conventional biomarkers, aspartate transaminase (AST) and creatine kinase (CK) enzymatic assays in rat toxicology studies. To evaluate the utility of these SKM biomarkers across species, they were assessed in 2 dog models: a drug-induced injury study in Beagle dogs and a 160 km endurance exercise run completed by Alaskan sled dogs. In the drug-induced injury model, mean sTnI and Myl3 plasma levels were 6- and 18-fold, respectively, compared with baseline as early as Study Day (SD) 15, while mean plasma AST and CK levels did not increase, and biopsy samples were non-remarkable for histopathology prior to SD 29 when degeneration was first noted. Peak group mean plasma responses over baseline for sTnI, Myl3, and Ckm biomarkers were 96-, 103-, and 11-fold, respectively, compared with 2.5-fold for AST and 3.8-fold for CK-enzymatic (CK-enz) assay. In the sled dog sustained exercise model, the peak response for all biomarkers was observed at the first sampling (2 h) after the completion of the run. The sTnI, Myl3, and Ckm mean fold peak values compared with baseline were 170-, 120-, and 150-fold, respectively, while AST increased 7-fold and CK-enz increased 29-fold. These findings support the conclusion that sTnI, Myl3, and Ckm are sensitive early tissue leakage biomarkers for monitoring SKM injury and effects of exercise in dog, extending their utility across preclinical species beyond the rat, and provide further support to investigate their translational utility to clinical trial settings to monitor for drug-induced SKM injury and ensure patient safety., (© The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Leukemia-Associated RhoGEF (LARG) is highly expressed in platelets, which are essential for maintaining normal haemostasis. We studied the function of LARG in murine and human megakaryocytes and platelets with Larg knockout (KO), shRNA-mediated knockdown and small molecule-mediated inhibition. We found that LARG is important for human, but not murine, megakaryocyte maturation. Larg KO mice exhibit macrothrombocytopenia, internal bleeding in the ovaries and prolonged bleeding times. KO platelets have impaired aggregation, α-granule release and integrin α2bβ3 activation in response to thrombin and thromboxane, but not to ADP. The same agonist-specific reductions in platelet aggregation occur in human platelets treated with a LARG inhibitor. Larg KO platelets have reduced RhoA activation and myosin light chain phosphorylation, suggesting that Larg plays an agonist-specific role in platelet signal transduction. Using two different in vivo assays, Larg KO mice are protected from in vivo thrombus formation. Together, these results establish that LARG regulates human megakaryocyte maturation, and is critical for platelet function in both humans and mice.

The use of sensitive biomarkers to monitor skeletal muscle toxicity in preclinical toxicity studies is important for the risk assessment in humans during the development of a novel compound. Skeletal muscle toxicity in Sprague Dawley Rats was induced with clofibrate at different dose levels for 7 days to compare standard clinical pathology assays with novel skeletal muscle and cardiac muscle biomarkers, gene expression and histopathological changes. The standard clinical pathology assays aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatine kinase (CK) enzyme activity were compared to novel biomarkers fatty acid binding protein 3 (Fabp3), myosin light chain 3 (Myl3), muscular isoform of CK immunoreactivity (three isoforms CKBB, CKMM, CKMB), parvalbumin (Prv), skeletal troponin I (sTnI), cardiac troponin T (cTnT), cardiac troponin I (cTnI), CKMM, and myoglobin (Myo). The biomarker elevations were correlated to histopathological findings detected in several muscles and gene expression changes. Clofibrate predominantly induced skeletal muscle toxicity of type I fibers of low magnitude. Useful biomarkers for skeletal muscle toxicity were AST, Fabp3, Myl3, (CKMB) and sTnI. Measurements of CK enzyme activity by a standard clinical assay were not useful for monitoring clofibrate-induced skeletal muscle toxicity in the rat at the doses used in this study., (Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Novel skeletal muscle (SKM) injury biomarkers that have recently been identified may outperform or add value to the conventional SKM injury biomarkers aspartate transaminase (AST) and creatine kinase (CK). The relative performance of these novel biomarkers of SKM injury including skeletal troponin I (sTnI), myosin light chain 3 (Myl3), CK M Isoform (Ckm), and fatty acid binding protein 3 (Fabp3) was assessed in 34 rat studies including both SKM toxicants and compounds with toxicities in tissues other than SKM. sTnI, Myl3, Ckm, and Fabp3 all outperformed CK or AST and/or added value for the diagnosis of drug-induced SKM injury (ie, myocyte degeneration/necrosis). In addition, when used in conjunction with CK and AST, sTnI, Myl3, CKm, and Fabp3 individually and collectively improved diagnostic sensitivity and specificity, as well as diagnostic certainty, for SKM injury and responded in a sensitive manner to low levels of SKM degeneration/necrosis in rats. These findings support the proposal that sTnI, Myl3, Ckm, and Fabp3 are suitable for voluntary use, in conjunction with CK and AST, in regulatory safety studies in rats to monitor drug-induced SKM injury and the potential translational use of these exploratory biomarkers in early clinical trials to ensure patient safety., (© The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Acute kidney injury (AKI) is a common and increasingly encountered complication in hospitalized patients with critical illness in intensive care units (ICU). According to the etiology, Sepsis-induced AKI (SAKI) is a leading contributor to AKI and significantly has very poor prognosis, which might be related to the late detection when the elevation of BUN and serum creatinine (SCr) is used. Many genes are up-regulated in the damaged kidney with the corresponding protein products appearing in plasma and urine. Some of these are candidate biomarkers for more timely diagnosis of SAKI. Therefore, extensive research efforts over this past decade have been directed at the discovery and validation of novel SAKI biomarkers to detect injury prior to changes in kidney function, a number of serum and urinary proteins, including NGAL, KIM-1, cystatin-C, IL-18, and L-FABP, have been identified for predicting SAKI before a rise in BUN and serum creatinine in several experimental and clinical trainings. Unfortunately, an ideal biomarker of SAKI with highly sensitivity and specificity has not been identified yet. Recent progresses in quantitative proteomics have offered opportunities to discover biomarkers for SAKI. In the present study, kidney tissue samples from SAKI mice were analyzed by two-dimensional differential gel electrophoresis (2D-DIGE), and 4 up-regulated proteins, which were actin (ACTB), myosin regulatory light chain 12B (MYL12B), myosin regulatory light polypeptide 9 (MYL9), and myosin regulatory light chain 12A (MYL12A) were identified by matrix assisted laser desorption ionization-time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS). Among all the varied proteins, MYL12B was validated by western blot. Interestingly, there was no change between the SAKI and control kidney tissues, however, phosphorylated MYL12B was detected to be consistent with the proteomics data. Furthermore, phosphorylated MYL12B was found similarly to be increased in SAKI plasma, while MYL12B was changeless in plasma of control group. Taking together, phosphorylated MYL12B may be employed as a potential plasma biomarker for the early diagnosis of SAKI.

Increased combined free light chains (cFLCs) are strongly prognostic of death in general populations and in patients with chronic kidney disease, but scarce data are available on cFLC in heart failure (HF). The aim of this study was to assess the dynamics and prognostic significance of cFLC levels in patients after admission with acute HF (AHF). cFLC measurements were compared in 49 patients with AHF, 37 patients with stable HF, 43 patients with stable coronary artery disease and without HF ("disease controls"), and 37 healthy controls. The association of cFLC with death and/or rehospitalization was assessed. Patients with AHF had significantly elevated cFLC levels, compared with other groups (p <0.001). Patients with stable HF showed higher levels of cFLCs than healthy controls. In patients with AHF, cFLC levels were correlated with cystatin C (Spearman's r = 0.63, p <0.001) and creatinine (Spearman's r = 0.47, p = 0.002). During 3-month follow-up, brain natriuretic peptide was reduced significantly (p = 0.017), but cFLCs did not change significantly. In a multivariate Cox regression analysis, the higher quartiles of cFLCs were significantly associated with death or readmission (hazard ratio 8.34, 95% confidence interval 2.38 to 29.22, p = 0.0009) after adjustment for age, gender, brain natriuretic peptide and cystatin C levels. Higher quartiles of cFLCs were prognostic for death alone (hazard ratio 14.0, 95% confidence interval 1.72 to 113.8, p = 0.014). In conclusion, increased serum cFLC concentrations in patients with AHF were independently associated with prognosis. In patients with AHF, elevated cFLC levels persist long after clinical stabilization, which may reflect immune disturbances and/or the reduced capacity of (perhaps functionally impaired) kidneys and the endothelium to eliminate them., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Treatment with trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of Human Epidermal Growth Factor Receptor 2 (HER2), very successfully improves outcomes for women with HER2-positive breast cancer. However, trastuzumab treatment was recently linked to potentially irreversible serious cardiotoxicity, the mechanisms of which are largely elusive. This study reports that trastuzumab significantly alters the expression of myocardial genes essential for DNA repair, cardiac and mitochondrial functions, which is associated with impaired left ventricular performance in mice coupled with significant ultrastructural alterations in cardiomyocytes revealed by electron microscopy. Furthermore, trastuzumab treatment also promotes oxidative stress and apoptosis in myocardium of mice, and elevates serum levels of cardiac troponin-I (cTnI) and cardiac myosin light chain-1 (cMLC1). The elevated serum levels of cMLC1 in mice treated with trastuzumab highlights the potential that cMLC1 could be a useful biomarker for trastuzumab-induced cardiotoxicity.

Inflammation and oxidative stress, elicited by Trypanosoma cruzi infection, are important pathologic events during progressive Chagasic cardiomyopathy. In this study, we infected Sprague-Dawley rats with T. cruzi, and treated with phenyl-α-tert-butylnitrone (PBN-antioxidant) and/or benznidazole (BZ-anti-parasite). We employed two-dimensional gel electrophoresis/mass spectrometry to investigate (a) the plasma proteomic changes associated with infection and disease development, and (b) the beneficial effects of PBN and BZ in controlling the disease-associated plasma profile. Matrix-assisted laser desorption ionization/time of flight (MALDI-TOF) tandem MS (MS/MS) analysis of differentially expressed (total 146) and oxidized (total 48) protein spots yielded 92 unique proteins. Our data showed that treatment with PBN and BZ restored the differential expression of 65% and 30% of the disease-associated proteins to normal level, respectively, and PBN prevented development of oxidative adducts on plasma proteins. Western blotting to detect dinitrophenyl-derivatized carbonyl-proteins revealed plasma proteins were maximally oxidized during acute infection. Functional and disease/disorder analyses allocated a majority of the differentially expressed and oxidized proteins into inflammation/immunity and lipid metabolism categories and to molecular pathways associated with heart disease (e.g. cardiac infarction, contractile dysfunction, hypertrophy, and hypertension) in chagasic rats, and to curative pathways (e.g. ROS scavenging capacity, immune regulation) in infected rats treated with PBN and/or BZ. We validated the two-dimensional gel electrophoresis results by Western blotting, and demonstrated that the disease-associated increased expression of gelsolin and vimentin and release of cardiac MYL2 in the plasma of chagasic rats was returned to control level by PBN/BZ treatment. Increased plasma levels of gelsolin, MYL2 and vimentin were directly correlated with the severity of cardiac disease in human chagasic patients. Together, these results demonstrate the plasma oxidative and inflammatory response profile, and plasma detection of cardiac proteins parallels the pathologic events contributing to Chagas disease development, and is of potential utility in diagnosing disease severity and designing suitable therapy for management of human chagasic patients.

The authors compared the mortality and cardiac biomarker responses in three outbred stocks of Sprague Dawley rats (CD/IGS, Sasco, Harlan) treated with isoproterenol hydrochloride. Cardiac injury was confirmed by histologic evaluation, and increases in cardiac troponin I concentration in serum were measured by two methods. CD/IGS rats had a higher incidence and earlier mortality compared with Sasco or Harlan rats. Harlan rats had lower severity scores for cardiomyocyte degeneration/necrosis compared with the other stocks. Post-isoproterenol treatment cardiac troponin I concentrations were greater in CD/IGS and Sasco rats compared with Harlan rats. Concentrations of cardiac troponin T followed a similar pattern to that of cardiac troponin I in rats treated with isoproterenol. Myosin, light chain 3 concentrations increased in all rats treated with isoproterenol, but there was no difference between the three stocks in the magnitude or pattern of the dose response. Increases in fatty acid binding protein 3 concentrations were detected in only the highest dose group at the earliest timepoint postdose for all three stocks of rats. Results of these studies illustrate the need for investigators to recognize the potential differences in response between stocks of Sprague Dawley rats treated with cardiotoxicants or novel chemical entities.

Since cardiac and skeletal myotoxicity affect the development of drug candidates, it is important to detect their toxicity at an early stage of drug development. For that purpose, in this study, the usefulness of several cardiac and skeletal myotoxic biomarkers in blood were evaluated using two rat models treated intraperitoneally with an acetylcholinesterase inhibitor carbofuran (CAF) or a synthetic catecholamine isoproterenol (ISO). The biomarkers assayed were fatty acid binding protein 3 (Fabp3), myosin light chain 1 (MLC1), cardiac troponin I (cTnI), cardiac troponin T (cTnT), aspartate transaminase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK). CAF and ISO treatment of rats induced greater increases in the levels of Fabp3, MLC1, cTnI and cTnT than in the levels of AST, LDH and CK. A kinetic analysis indicated that the levels of all of the biomarkers had returned to the basal level by 24h after drug administration. Pathological examination revealed lesions in the heart, mainly at the left ventricle and septum, in both CAF- and ISO-treated rats. CAF-treated rats showed widespread lesions of skeletal muscle that were independent of muscle fiber type, while in ISO-treated rats locoregional lesions were observed only in slow twitch muscle. Receiver operating characteristic curve analysis of the sensitivity of the tested biomarkers indicated that MLC1 and cTnT were the most effective biomarkers of cardiotoxicity. For skeletal myotoxicity, Fabp3 and MLC1 were the most effective biomarkers based on the specific tissue distribution of these proteins. Conversely, the rapid blood clearance of these markers should be taken into account when considering the use of these biomarkers.

Background: Shape change and centralization of granules surrounded by a microtubular coil (internal contraction) are among the earliest morphologic changes observed following platelet activation. Myosin IIA contributes to initiation of platelet shape change, but its role in internal contraction has not been defined., Objective: To define the contribution of myosin IIA to platelet internal contraction., Methods: Aspirin-treated platelets suspended in calcium-free buffer were activated with a low concentration (25 nm) of the thromboxane A(2) analog U46619 which initiated shape change and internal contraction via a Rho kinase pathway. Shape change and internal contraction were assessed by aggregometry and transmission electron microscopy (TEM), and Rho activation and myosin regulatory light chain (MRLC) phosphorylation were studied concurrently., Results and Conclusions: Low-concentration blebbistatin (10 microm) inhibited internal contraction in the majority of platelets with minimal inhibition of shape change without significant suppression of MRLC phosphorylation. Higher blebbistatin concentrations (25-100 microm) produced concentration-dependent inhibition of aggregation, shape change, Rho activation, and MRLC phosphorylation. These data demonstrate: (i) direct platelet myosin IIA participation in internal contraction; and (ii) inhibition of Rho activation and MRLC phosphorylation by >10 microm blebbistatin.

The integrin alpha(IIb)beta(3) plays a critical role in mediating clot retraction by platelets which is important in vivo in consolidating thrombus formation. Actin-myosin interaction is essential for clot retraction. In the present study, we demonstrate that the structurally distinct Src kinase inhibitors, PP2 and PD173952, significantly reduced the rate of clot retraction, but did not prevent it reaching completion. This effect was accompanied by abolition of alpha(IIb)beta(3)-dependent protein tyrosine phosphorylation, including PLCgamma2. A role for PLCgamma2 in mediating clot retraction was demonstrated using PLCgamma2-deficient murine platelets. Furthermore, platelet adhesion to fibrinogen leads to MLC phosphorylation through a pathway that is inhibited by PP2 and by the PLC inhibitor, U73122. These results demonstrate a partial role for Src kinase-dependent activation of PLCgamma2 and MLC phosphorylation in mediating clot retraction downstream of integrin alpha(IIb)beta(3).

Background: The need for a laboratory marker of myocardial ischemia has been alluded to for at least the last decade., Aim: The aim of this study was to evaluate the diagnostic importance of the myosin light chain-1 (MLC-1), clusterin and Reg-Ialpha in patients with suspected myocardial ischemia., Methods: A group of 176 at high-risk for myocardial ischemia subjects was evaluated and divided into two subgroups using myocardial SPECT (Single Photon Emission Computed Tomography) - individuals with and without signs of myocardial ischemia. Laboratory markers in venous blood were repeatedly examined in all subjects: a) immediately prior to SPECT: C-reactive protein, Haemoglobin, Hematocrite, Lactate, MLC-1, Clusterin, Reg-Ialpha b) at subjective maximum: Hb, Htc, lactate, MLC-1, Clusterin, Reg-Ialpha c) 30 min after stress levels reached their peak: MLC-1, Clusterin, Reg-Ialpha and d) 60 min after peak stress levels: MLC-1, Clusterin, Reg-Ialpha., Results: Patients were divided into subgroups according to their positive and negative SPECT results (positive: n = 37; negative: n = 139). MLC-1 values were different for all 4 blood collections. An increase in MLC-1 > 2.2 mg/l showed 64 % sensitivity and 88 % specificity for the diagnosed presence of myocardial ischemia (AUC 0.81; LR+ 5.9; PPV+ 68 % and NPV- 87 %). There was no significant difference between the groups in terms of Clusterin and Reg-Ialpha for any of the sampling periods., Conclusions: High diagnostic efficacy of detectable MLC-1 was shown for the diagnosis of latent myocardial ischemia. Measurement of serum Clusterin or Reg-Ialpha did not sufficient for the diagnosis of latent myocardial ischemia.

Background: This study was designed to test whether circulating levels of myocardium-specific proteins serve as useful markers for the prognosis of patients with congestive heart failure., Methods and Results: Seventy-eight patients with congestive heart failure from dilated cardiomyopathy but in a stable condition were enrolled, and their blood was sampled for measurements of myosin light chain-I (MLC-I), troponin T (TnT), heart fatty-acid-binding protein (H-FABP), and creatine kinase isoenzyme MB (CK-MB). The patients were then followed up for 951 +/- 68 days, with the endpoint being acute deterioration. A univariate analysis revealed that MLC-I, TnT, H-FABP, and CK-MB were significant predictors for acute deterioration of heart failure. Application of the Kaplan-Meier method using cutoff values determined by analysis of receiver operating characteristics curves demonstrated that the incidence of acute deterioration was significantly higher in patients with higher values of MLC-I (61.9%), TnT (52.4%), H-FABP (50.0%), or CK-MB (38.6%) than in those with lower values of these markers (15.8%, 20.4%, 13.6%, and 16.1%, respectively)., Conclusions: Increased circulating levels of the specific myocardial proteins are related to a higher probability of future acute deterioration of congestive heart failure in patients in a stable condition associated with dilated cardiomyopathy.

Myosin light chains-1 (MLC-1) have been recently associated with the markers of heart function (NYHA, LVEF, NT-proBNP). Verification of the relationship between markers of heart function (New York Heart Association classification (NYHA), left ventricle ejection fraction determination (LVEF), N terminal prohormone of natriuretic peptide B type BNP (NT-proBNP) and concentrations of myosin light chains-1 (MLC-1) was assessed. Patients examined for dyspnea without signs of acute coronary syndrome. All patients underwent echocardiography (calculation of left ventricle ejection fraction--LVEF) and in the serum of all subjects NT-proBNP (ELEIA) and MLC-1 (ELISA) were determined. In the 38 patients (21 men, 17 women), mean age of 58 years (+/-12 years as 1 SD), a significant negative correlation was found between NT-proBNP and LVEF (r = - 0.47; p = 0.02, Spearman). The median levels of NT pro-BNP were closely associated with NYHA classification (type II--584 ng/l, type III--2792 ng/l, type IV--6400 ng/l; p < 0.05). Individuals with clinical NYHA IV differed significantly in median MLC-1 concentrations from persons with clinical NYHA classification II and III (type II--5.7 ng/l, type III--8.9 ng/l, type IV--17 ng/l; p < 0.05). A significant negative correlation between MLC-1 and LVEF (-0.35; p < 0.03) and significant positive correlations between MLC-1 and NT-proBNP (0.42; p < 0.012) were found. In conclusion MLC-1 cannot be used as a diagnostic marker in differential diagnosis of dyspnea.

Purpose of Review: This paper reviews recent advances in heart failure biomarkers for identification of disease precursors, subclinical disease, and onset or progression of overt disease., Recent Findings: Heart failure biomarkers can be categorized empirically as neurohormonal mediators, markers of myocyte injury and remodeling, and indicators of systemic inflammation. Brain natriuretic peptide is the most widely studied, with a potentially important but evolving role for determining prognosis and as a surrogate endpoint in clinical trials. Strong evidence exists for use of brain natriuretic peptide in the diagnosis of acute heart failure and for improved clinical outcomes with a brain natriuretic peptide-guided approach to heart failure care. The use of brain natriuretic peptide as a screening tool for asymptomatic left ventricular systolic dysfunction, or to distinguish systolic from diastolic heart failure, is not supported by current data. Markers of myocyte injury, including troponins, heart-type fatty acid binding protein, and myosin light chain-1, may further improve heart failure prognostication in conjunction with plasma brain natriuretic peptide. Biomarkers of matrix remodeling and inflammation have emerged as potential preclinical indicators to identify individuals at risk of developing clinical heart failure. A role for cellular adhesion molecules may also emerge in identifying those at risk for cardiovascular thrombotic complications, such as stroke., Summary: The spectrum of heart failure biomarkers and their potential clinical applications continues to grow. Ongoing research on multimarker strategies will likely identify biomarker combinations that are optimal at various stages during the evolution of heart failure, ranging from their use for screening, diagnosis, determining prognosis, and guiding management.

Little is known about cardiac abnormalities in neuroleptic malignant syndrome (NMS) in Parkinson's disease (PD), although high levels of serum creatine kinase (CK) suggest the presence of cardiac involvement. We have also been aware of elevated serum myosin light chain I (MLCI) in these patients with no clear evidence of an acute coronary syndrome. To evaluate cardiac involvement in NMS in PD, we recorded the electrocardiogram (ECG) and measured serum MLCI and CK-MB levels. Plasma levels of noradrenaline and adrenaline were also determined. The patients were classified based on the in-hospital outcome into 55 survivors and 5 nonsurvivors. Age- and gender-matched PD patients without NMS served as controls (n = 51). All patients had high serum concentrations of CK-MB and MLCI. The mean values of CK, CK-MB, MLCI, adrenaline and noradrenaline were higher in both patient groups as compared to control subjects, and the values in nonsurvivors were significantly higher than those in survivors. A positive correlation was observed between serum MLCI and CK levels (p < 0.01), and between serum MLCI levels and plasma noradrenaline concentrations (p < 0.01). ECG abnormalities such as prolonged QTc interval, abnormal Q wave, ST elevation and T wave inversion were observed in all nonsurvivors and 32 (58.2%) survivors. We conclude that myocardial involvement is common in patients with NMS even when they have no symptoms suggestive of myocardial injury, and MLCI and CK-MB as well as ECG are useful indicators of mortality., ((c) 2005 S. Karger AG, Basel)

This review discusses the role of biochemical markers of myocyte injury in patients with chronic congestive heart failure. Heart specific assays have been developed for the measurement of cardiac troponin T (cTnT), cardiac troponin I (cTnI), heart type fatty acid binding protein (H-FABP), and myosin light chain 1 (MLC-1). Concentrations of these biochemical markers increase in the absence of ischaemic events in the subset of patients with heart failure whose long term outcomes are most adverse. The markers are easy to measure serially and it is therefore easy to follow patients without inter-observer variability. The serial clinical use of these markers, separately or in combination, will sharpen our understanding of the state of heart failure.

Background: Serum levels ob biochemical markers for acute myocardial infarction (AMI) can be increased in patients with chronic renal failure (CRF) or skeletal muscle injury, creating diagnostic confusion. We evaluated the clinical utility of cardiac troponin I (cTnI) as a marker of AMI, particularly in patients with CRF., Methods: Subjects consisted of 59 healthy volunteers and 102 patients: 61 with CRF undergoing hemodialysis (CRF-HD), 10 with CRF under conservative therapy (CRF-CT), 21 with renal disease (RD), and 10 with muscle disease (MD). Patients with RD, CRF, and MD were evaluated to verify the absence of myocardial injury. We developed an immunoradiometric assay to measure serum cTnI using monoclonal antibodies. The lower limit of detection was 0.33 micro g/l. Serum cTnI, creatine kinase (CK), CK-MB, cardiac troponin T (first-, second-, and third-generation assay: cTnT-I, cTnT-II, and cTnT-III), and cardiac myosin light chain 1 (cMLC1) were measured., Results: cTnI was not detected in healthy volunteers or patients with CRF, RD, or MD. In patients with CRF-HD, elevated levels occurred in 4.9% (3/61) for CK, 0% (0/61) for CK-MB, 39.5% (15/38) for cTnT-I, 7.3% (3/41) for cTnT-II, 13.0% (3/23) for cTnT-III, and 77.0% (47/61) for cMLC1; and in patients with MD the levels were increased in 70% (7/10) for CK, 50% (5/10) for CK-MB, 44.4% (4/9) for cTnT-I, 20% (2/10) for cTnT-II, and 50% (5/10) for cMLC1., Conclusions: cTnI is a highly specific marker for AMI and is particularly useful for detecting AMI in patients with CRF or MD. Serum levels of biochemical markers for acute myocardial infarction (AMI) can be increased in patients with chronic renal failure (CRF) or skeletal muscle injury, creating diagnostic confusion. We evaluated the clinical utility of cardiac troponin I (cTnI) as a marker of AMI, particularly in patients with CRF.

Objective: To test the hypothesis that myocardium specific proteins may be useful markers for evaluating the severity of congestive heart failure., Methods: Serum concentrations of myosin light chain I (MLC-I), heart fatty acid binding protein (H-FABP), creatine kinase isoenzyme MB (CK-MB), and troponin T (TnT) and plasma concentrations of brain natriuretic peptide (BNP) were determined in 48 patients with acute deterioration of congestive heart failure, both before and after effective treatment., Results: Before treatment, MLC-I (mean (SEM) 3.2 (2.2) microg/l), H-FABP (9.0 (3.5) microg/l), TnT (30 (21) ng/l), and BNP (761 (303) ng/l) were higher than the normal reference range, and concentrations of CK-MB (5.4 (2.9) microg/l) were near normal. Treatment of congestive heart failure with conventional medication significantly decreased the concentrations of MLC-I (1.2 (0.3) microg/l, p < 0.0001), H-FABP (6.0 (2.0) microg/l, p < 0.0001), CK-MB (2.9 (1.5) microg/l, p < 0.0001), TnT (9 (1) ng/l, p < 0.001), and BNP (156 (118) ng/l, p < 0.0001). The decreases in H-FABP and CK-MB concentrations after treatment correlated with the decrease in BNP concentrations (p < 0.05). The absolute concentrations of MLC-I, H-FABP, CK-MB, and TnT correlated positively with those of BNP (p < 0.01)., Conclusions: These findings suggest that MLC-I, H-FABP, CK-MB, and TnT may be used as reliable markers for the evaluation of the severity of congestive heart failure.

The myocardial contractile protein myosin light chain 1 isoform (MLC-1) is released into the circulation during myocyte necrosis and could thus be a marker of low-grade myocardial damage and of poor prognosis in patients with heart failure. Two hundred eighteen patients with stable heart failure (ejection fraction [EF] <35%) and in New York Heart Association (NYHA) class III to IV had MLC-1 measured at baseline and 1 month after being randomized to the direct vasodilator flosequinan or placebo. Patients were followed a mean of 302 +/- 142 days. The prognostic value of an increase in MLC-1 above the 98th percentile of normal controls was compared with that of conventional prognostic variables in heart failure. MLC-1 was increased in over half of patients at baseline and 1 month, and this was associated with increased age, NYHA class IV, and renal insufficiency. By Kaplan-Meier survival analysis, patients with a baseline increase in MLC-1 had a greater mortality (26%) than those without an increase (15%) (p = 0.043). A significant interaction among MLC-1, survival, and treatment was found (p = 0.043). In the placebo group, MLC-1 was associated with increased mortality (29% vs 12%, p = 0.025), whereas there was no significant difference among patients receiving flosequinan. In a multivariate logistic regression model including age, treatment, and left ventricular (LV) ejection fraction, the MLC-1 chain was most predictive of mortality (p = 0.049). Thus, circulating MLC-1 is elevated in over half of patients with stable severe heart failure, and this increase is associated with a poor prognosis. Flosequinan treatment eliminates this association, highlighting the complexity of the relation between cardiac myocyte damage, drug treatment, and mortality.

Objective: To study several markers of myocardial injury in relation to aortic cross-clamping and cardiopulmonary bypass (CPB) after coronary artery bypass graft (CABG) surgery., Design: Prospective observational study., Setting: University hospital., Participants: Thirty adult patients who underwent elective CABG surgery with aortic cross-clamping and CPB., Measurements and Main Results: Serum levels of interleukin-6 (IL-6), interleukin-8 (IL-8), troponin-T (TnT), myosin light chain I (MLCI), and MB isoenzyme of creatine kinase (CK-MB), as markers of myocardial injury, were measured after induction of anesthesia for baseline values, then again at the end of surgery and on postoperative days 1, 3, and 5. IL-6, IL-8, and CK-MB levels were significantly elevated in the early postoperative stage. TnT significantly increased from the end of surgery to postoperative day 5. MLCI increased also but later than TnT. Aortic cross-clamping time correlated positively with peak TnT (r = 0.51, p < 0.05), TnT level on postoperative day 1 (r = 0.69, p < 0.01), and MLCI level on postoperative day 5 (r = 0.45, p < 0.05). CPB time was correlated only with peak TnT (r = 0.47, p < 0.05)., Conclusions: The increase in TnT level is strongly related to aortic cross-clamping., (Copyright 2002, Elsevier Science (USA). All rights reserved.)

Objective and Methods: We examined the prognostic significance of electrocardiographic predictors (number of leads with ST depression, maximal ST depression, QT dispersion), C-reactive protein, fibrinogen, myosin light chain 1 and creatine kinase MB fraction in 62 patients with unstable angina showing ST depression during an anginal attack., Results: During the 90-day follow-up period, 15 patients (24%) exhibited new cardiac events (death, myocardial infarction or urgent revascularization). Using multivariate analysis, the number of leads with ST depression [relative risk 6.305 (95% confidence intervals 1.831-21.71), p<0.01] during an anginal attack was found to be an independent risk factor to predict cardiac events. Other predictors did not have prognostic significance., Conclusion: The number of leads with ST depression during an anginal attack is an independent risk predictor for new cardiac events in high risk patients with unstable angina.

Objective: Myocarditis has been described as a complication of influenza. Patients with influenza may have symptoms and abnormal laboratory data (including chest X-ray, electrocardiogram, etc.) suggestive of myocarditis, although few observations have been made regarding the prevalence of asymptomatic myocardial injury. We investigated whether influenza can produce myocardial injury without cardiac symptoms., Methods: During the epidemic of influenza A (H3N2) from 1998 to 1999 in Japan, we examined possible cardiac muscle damage associated with influenza in patients without apparent clinical myocardial injury by measuring serum myosin light chain concentrations., Patients: Ninety-six influenza-positive patients (46 males and 50 females, average age 43.4 years) without impaired renal function were studied., Results: Of these patients, 11 (11.4%) had elevated serum myosin light chain I concentrations., Conclusion: Asymptomatic myocardial injury may be present in patients with influenza even when they have no symptoms suggestive of myocardial injury.

Background: Biochemical markers have been an integrative part of non-invasive diagnostic strategies in cardiology for nearly 50 years, experiencing a renascence by the recently acknowledged prognostic potential of cardiac troponins in acute coronary syndromes., Diagnosis: According to the guidelines of the National Academy of Clinical Biochemistry and the International Federation of Clinical Chemistry cardiac troponin T and cardiac troponin I should be considered as the new "gold markers" of ischemic myocardial injury. One characteristic feature of these new markers is the improved diagnostic potential, reflected by the choice of two cut-off values to distinguish minor myocardial injury from acute myocardial infarction. In addition, cardiac troponins allow risk stratification in the clinical setting of acute coronary syndromes: approximately threefold higher mortality rate for patients with rest angina or ST segment elevation and cardiac troponin elevation on admission. Other indications for cardiac marker analysis are monitoring of therapeutic success in case of invasive and non-invasive reperfusion strategies and non-invasive diagnosis of non-ischemic myocardial injury (myocarditis, cardiac contusion and chemotherapy)., Conclusion: Biochemical cardiac markers are a useful tool in the diagnosis of both ischemic and non-ischemic myocardial injury. Among these, cardiac troponins seem to become the gold markers for the new millennium.

Objectives: The relationships between cardiac troponin I, various biochemical markers, and chronic-phase left ventricular ejection fraction (LVEF) after successful direct percutaneous transluminal coronary angioplasty (PTCA) were examined in 36 patients with acute myocardial infarction., Methods: Biochemical markers were measured on admission, immediately after, and from 6 hours to 9 days after PTCA., Results: The time to peak values were: creatine kinase-MB 9.7 hours, cardiac troponin I 9.8 hours, myoglobin 10.7 hours, creatine kinase 10.6 hours, cardiac troponin T 18.6 hours, and myosin light chain 68.9 hours. Cardiac troponin T, cardiac troponin I and myosin light chain levels were elevated over 9 days after successful direct PTCA. Chronic-phase LVEF inversely correlated with peak values of creatine kinase-MB (r = -0.519, p < 0.01), cardiac troponin T (r = -0.500, p < 0.01), cardiac troponin I (r = -0.441, p < 0.05) and creatine kinase (r = -0.411, p < 0.05). The values of cardiac troponin I, cardiac troponin T, creatine kinase and creatine kinase-MB at each sampling point were significantly inversely related to chronic-phase LVEF. The value of cardiac troponin I at each time point for 7 days correlated well with chronic-phase LVEF., Conclusions: Cardiac troponin I has high specificity for predicting long-term cardiac function after successful direct PTCA when early values are unavailable.

Background: Although thrombus formation plays a major role in acute coronary syndromes, few studies have evaluated a thrombus marker in risk stratification of patients with chest pain. Furthermore, the relation between markers that reflect myocardial injury and thrombus formation that may predict events in a heterogeneous patient population is unknown. This study correlated markers of thrombus and myocardial injury with early and late ischemic events in consecutive patients with chest pain., Methods and Results: Serum troponin I (TnI), myoglobin, and myosin light chain levels were obtained from 247 patients and urinary fibrinopeptide A (FPA) from 178 of the 247. By multivariate analysis, patients with an elevated FPA level were 4.82 times more likely to die or have myocardial infarction, unstable angina, and coronary revascularization at 1 week (P=0.002, 95% CI 1.78, 13.03), whereas those with an elevated TnI (>0.2 ng/mL) were 9.41 times more likely (P<0.001, 95% CI 2.84, 31.17). At 6 months (excluding the index event), an elevated FPA level was an independent predictor of events, with an odds ratio of 9.57 (P<0.001, C1 3.29, 27.8), and was the only marker to predict a shorter event-free survival (P<0.001). The other markers did not independently correlate with cardiac events, although MLC incrementally increased early predictive accuracy in combination with the FPA and TnI., Conclusions: Elevated FPA and TnI correlated with cardiac events during the initial week in patients presenting to the Emergency Department with chest pain. FPA predicted adverse events and a shorter event-free survival at 6 months.

Four biochemical markers, creatine kinase (CK)-MB isoenzyme, myoglobin, myosin light chains and troponin I, were studied in 1,338 patients presenting to the emergency department with chest pain suggestive of coronary artery disease (CAD). One hundred and eighty-seven patients had an acute myocardial infarction (MI). At least one of the four markers was over the threshold on the first sample in 78% of MI patients, as compared to only 40% with an elevated CK-MB. After 4 h, 88% had at least one marker elevated. None of the 69 patients with atypical chest pain, no history of CAD, no markers over threshold on the first sample and a normal electrocardiogram had an acute MI or unstable angina. If we had discharged this group, we would have saved USD 264,000, estimating a cost of USD 2,000 per day. Using four biochemical markers improved the early diagnosis of CAD and may help identify groups suitable for early discharge., (Copyright 2000 S. Karger AG, Basel)

Objective: To evaluate the use of cardiac troponin I (cTnI), creatine kinase-MB(mass) (CK-MB(mass)), myosin light chain 1 (MLC 1), and myoglobin in identifying "high risk" patients with chest pain who will experience serious cardiac events (SCEs) in hospital., Design: Prospective study., Setting: University affiliated medical centre in Philadelphia, USA., Patients: 208 patients with chest pain, at > 7% risk of acute myocardial infarction (MI), but without new ST segment elevation on their presenting ECG., Interventions: cTnI, CK-MB(mass), MLC 1, and myoglobin concentrations were obtained on admission (0 hour) and at 4, 8, 16, and 24 hours., Main Outcome Measures: The sensitivity, specificity, positive and negative predictive value, and pre- and post-test probabilities of patients suffering an SCE in hospital were determined. SCEs included cardiac death, acute MI, cardiac arrest, life threatening cardiac arrhythmia, cardiogenic shock, and urgent coronary revascularisation., Results: Admission concentrations of all markers were poor predictors of SCEs in hospital but improved substantially at subsequent timepoints. cTnI and CK-MB(mass) were consistently the most useful prognostic indicators. If both were negative at 0, 4, and 8 hours, then 99% (95% confidence interval 96% to 100%) of patients remained free from SCEs. The only SCEs not thus predicted were revascularisation procedures and associated complications. Additional tests after 8 hours, or the inclusion of additional markers, did not improve predictive accuracy further., Conclusions: Patients with high risk clinical features on admission who have negative cTnI and CK-MB(mass) concentrations at 0, 4, and 8 hours later have a favourable in-hospital prognosis and could be considered for early triage out of coronary care units.

Platelets respond to various stimuli with rapid changes in shape followed by aggregation and secretion of their granule contents. Platelets lacking the alpha-subunit of the heterotrimeric G protein Gq do not aggregate and degranulate but still undergo shape change after activation through thromboxane-A2 (TXA2) or thrombin receptors. In contrast to thrombin, the TXA2 mimetic U46619 led to the selective activation of G12 and G13 in Galphaq-deficient platelets indicating that these G proteins mediate TXA2 receptor-induced shape change. TXA2 receptor-mediated activation of G12/G13 resulted in tyrosine phosphorylation of pp72(syk) and stimulation of pp60(c-src) as well as in phosphorylation of myosin light chain (MLC) in Galphaq-deficient platelets. Both MLC phosphorylation and shape change induced through G12/G13 in the absence of Galphaq were inhibited by the C3 exoenzyme from Clostridium botulinum, by the Rho-kinase inhibitor Y-27632 and by cAMP-analogue Sp-5,6-DCl-cBIMPS. These data indicate that G12/G13 couple receptors to tyrosine kinases as well as to the Rho/Rho-kinase-mediated regulation of MLC phosphorylation. We provide evidence that G12/G13-mediated Rho/Rho-kinase-dependent regulation of MLC phosphorylation participates in receptor-induced platelet shape change.

Several cardiac serum markers such as cardiac myosin light chain, creatine kinase MB, and cardiac troponins have been shown to be elevated in patients with acute myocardial infarction. These markers are well utilized as clinical indicators for diagnosis and prognosis of myocardial necrosis. Recent studies have strongly indicated that cardiac structural protein troponin T and I are predictive of future cardiac events in patients with acute coronary syndromes including unstable angina pectoris. Immunoassays have also been developed to measure serum levels of cardiac troponins in recent years. These biochemical markers may be useful as a guide for intervention in the near future.

A 55-year-old man had rhabdomyolysis and myocardial damage induced by palytoxin. Weakness and myalgia of four extremities occurred five hours after eating a fish. Rhabdomyolysis developed and the serum creatine phosphokinase (CK) was elevated to 40,000 IU/l on the 3rd day. Gastric lavage with activated charcoal and forced mannitol-alkaline diuresis therapy were performed. The patient recovered with no complication such as renal failure. In this case, palytoxin was suggested to induce myocardial damage which was demonstrated by an elevation of the myosin light chain level and a change in electrocardiogram.

To establish serum myosin light chain I (MLCI) as a severity and prognostic marker for patients with acute myocardial infarction (AMI), we measured the serum levels of MLCI in 71 patients with first AMI daily for 1 week after the onset and classified them into four groups by the peak LCI: group 1, > or =2.5 ng/ml but <10 ng/ml; group 2, > or =10 ng/ml but <25 ng/ml; group 3, > or =25 ng/ml but <50 ng/ml; and group 4, > or =50 ng/ml (MLCI grade). The patients in group 1 were likely to show non-Q-wave infarction. The patients in groups 1 and 2 were likely to show redistribution on exercise thallium-201 scintigraphy, suggesting frequent residual ischemia in these groups. The patients in group 4 were likely to show higher Forrester's subset and lower cardiac index at admission and lower left ventricular ejection fraction at discharge. Recurrent angina was equally found in all groups. Severe complications or death were found in patients in groups 3 and 4. Thus the MLCI grade can be used as a simple marker for evaluating the severity of patients with AMI.

Acute coronary syndrome encompasses the entities acute MI, unstable AP and sudden cardiac death. The syndrome of unstable AP covers a very heterogenous group of patients. Recent pathological post-mortem investigations have revealed, that unstable AP leading to MI or sudden cardiac death is frequently preceded by microinfarctions. Despite the fact that thrombus formation is recognized as the major cause, the role of coronary artery spasm seems also important. Therefore, the pathological hallmark of ACS is at present thought to be caused by an active coronary plaque (the culprit lesion), which is often the site of intermittent occlusion and of thrombus formation, with or without vasospasm. The release of myocardial cell constituents in connection with these microinfarctions is to be expected. In order to detect these, diagnostic tools sensitive to myocardial injury and specific for myocardial tissue must be employed. According to WHO the criteria for the diagnosis of acute MI are based on clinical history, electrocardiographic changes, and enzymes in serum. Although these criteria are quite adequate in most cases, they are not present or easily discernible in all acute MI patients. The clinical symptoms are and will remain insensitive and nonspecific indicators of acute MI. Electrocardiographic alterations are carefully described, but sometimes less applicable due to non-interpretable ECG's. During the last decades, activity measurements of cardiac enzymes, and especially the isoenzymes of CK and LD, have become the final arbiters by which myocardial damage is diagnosed or excluded. However, they are not fully cardiospecific and have a low sensitivity to detect MMI, retaining a high specificity. Improved immunoassays have therefore been developed measuring the mass concentration of CK-MB instead of its catalytic activity, as well as immunoassays measuring structural proteins of the heart i.e., TnT, a tropomyosin-binding protein of the troponin regulatory complex located on the thin filament of the contractile apparatus of the myocyte; and MLC, a component of the thick filament of the contractile apparatus of the myocyte. We, and others, have shown that minor ischaemic myocardial injury can be detected by CK-MB mass immunoassays in around one-fourth to one-third of patients with unstable AP or in whom an acute MI has been ruled out. However, the prognostic significance of this identification has not been investigated. A priori, it is known that 5-20% of patients with unstable AP have a poor prognosis, with progression to acute MI or cardiac death within the first year. Additional, non-Q wave MI may also be considered a relatively unstable condition associated with a lower initial mortality but a higher risk of later MI/cardiac death. It is of further importance, that although the incidence of unrecognized MI is less than that of clinically apparent MI, the long-term prognosis for unrecognized MI appears to be similar to, and as serious as, that following detected MI. Therefore, in order to follow-up this subgroup identification based on CK-MB mass levels, we subsequently carried out a prognostic study. It demonstrated a significantly increased risk of cardiac events (i.e., non-fatal acute MI, cardiac death) in patients with significant fluctuations of CK-MB mass in serum. A similar observation has been supported by others using the rate of change in serial samples of CK-MB mass. Further, we demonstrated a good correlation between elevated CK-MB mass levels and a poor prognosis, when using a fixed discrimination limit. However, an increasing number of CK-MB mass immunoassays have been developed, and a standardization of CK-MB mass is urgently needed, as at present each laboratory determines its own reference levels and discriminatory values leading to the risk of diagnostic confusion. (ABSTRACT TRUNCATED)

Background: Cardiac troponin I (TnI) and troponin T (TnT) are highly specific myocardial markers., Objective: To determine whether their serum levels can be used to estimate myocardial infarct size soon after reperfusion., Methods: We measured the serum levels of TnI, TnT, and creatine kinase every 3 h, and the serum cardiac myosin light chain I (MLCI) every 24 h, in 42 patients with acute myocardial infarction in whom reperfusion therapy had successfully been performed. We calculated the severity of regional hypokinesis by analyzing the follow-up ventriculograms with the centerline method., Results: The time from reperfusion to the peak level for TnI was 6.1 +/- 3.5 h, significantly shorter than those for creatine kinase (7.5 +/- 4.1 h) and MLCI (55 +/- 28 h). The time to peak level for TnT (6.8 +/- 4.0 h) differed significantly from that for MLCI but not from that for creatine kinase. There was a significant correlation between the peak levels of TnI and TnT (r = 0.86). The peak TnI and TnT levels were correlated well to the peak creatine kinase level (r = 0.67 and 0.69, respectively), total creatine kinase release (r = 0.66 and 0.66), and the peak MLCI level (r = 0.71 and 0.80). We observed excellent correlations between the peak levels of TnI and TnT, and regional hypokinesis (r = -0.84 and -0.85, respectively). These were comparable to the correlations between regional hypokinesis and the peak creatine kinase level (r = 0.75), total creatine kinase release (r = -0.72), and the peak MLCI level (r = -0.76)., Conclusions: These results suggest that the peak serum levels of TnI and TnT in patients with successful reperfusion are accurate and early indices of infarct size.

A 53-year old woman developed slowly progressive dysarthria, mild enlargement of the tongue and dysphagia since 1 year ago. All neurological differential diagnoses that could have explained the bulbar symptoms were excluded. The swallowing sequence was pathologic and immunoglobulins were markedly reduced. A bone marrow biopsy revealed light chain myeloma grade III. Amyloid deposits were found in the tongue but not in the kidneys. Oro-pharyngeal amyloidosis was held responsible for the described complaints. It is concluded that multiple myeloma must be considered in the differential diagnosis of bulbar paralysis and that biopsy of specific lesions is necessary to confirm local amyloidosis.