Two serine residues located adjacently in the heart-specific N-terminus of cardiac troponin I can be phosphorylated in vivo. Both residues are sequentially phosphorylated and dephosphorylated by cAMP-dependent protein kinase (PKA) and protein phosphatase 2A (PP2A). The concentration changes of the different troponin I species have been determined separately for the phosphorylation and dephosphorylation reaction and approximated by time courses predicted by a reaction model. Dependent on the concentration ratio of active protein kinase/protein phosphatase, four different troponin I species can be generated; one nonphosphorylated, two monophosphorylated and one bisphosphorylated. This pattern generation will be observed in proteins phosphorylated and dephosphorylated by a single protein kinase and phosphatase on more than one site and is a new principle inherent in signal cascades.
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http://dx.doi.org/10.1111/j.1432-1033.1995.tb20722.x | DOI Listing |
J Gen Physiol
March 2025
Department of Animal, Veterinary, and Food Sciences, College of Agricultural and Life Sciences, University of Idaho, Moscow, ID, USA.
The mechanisms underlying cooperative activation and inactivation of myocardial force extend from local, near-neighbor interactions involving troponin-tropomyosin regulatory units (RU) and crossbridges (XB) to more global interactions across the sarcomere. To better understand these mechanisms in the hearts of small and large mammals, we undertook a simplified mathematical approach to assess the contribution of three types of near-neighbor cooperative interactions, i.e.
View Article and Find Full Text PDFAm Heart J Plus
January 2025
Department of Emergency Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
Background: Identifying and eliminating health disparities is a public health priority. The goal of this analysis is to determine whether cardiac testing or outcome disparities exist by race or sex in patients with detectable to mildly elevated serum troponin.
Methods: We conducted a secondary analysis of the CMR-IMPACT trial that randomized patients with symptoms suggestive of acute coronary syndrome and a detectable or mildly elevated troponin measure from 4 US hospitals to an early invasive angiography or cardiac MRI strategy.
J Int Med Res
January 2025
Cardiovascular Surgery, University Hospital of Lausanne, Lausanne, Switzerland.
Objective: The definition of coronary artery bypass graft (CABG)-associated myocardial infarction (MI) is controversial because the postoperative increases in cardiac enzyme activities are multifactorial in origin.
Methods: We performed a retrospective case-control study of patients who experienced perioperative MI (cardiac enzyme release, electrocardiographic changes, dysfunction on echocardiography) and those without ischemia to identify risk factors and enzyme activity thresholds.
Results: The estimated incidence of CABG-associated MI was 2.
Clin Chem Lab Med
January 2025
Deparment of Laboratory Medicine, 16268 La Paz University Hospital, Madrid, Spain.
Objectives: Cardiac biomarkers are useful for the diagnostic and prognostic assessment of myocardial injury (MI) and heart failure. By measuring specific proteins released into the bloodstream during heart stress or damage, these biomarkers help clinicians detect the presence and extent of heart injury and tailor appropriate treatment plans. This study aims to provide robust biological variation (BV) data for cardiac biomarkers in athletes, specifically focusing on those applied to detect or exclude MI, such as myoglobin, creatine kinase-myocardial band (CK-MB) and cardiac troponins (cTn), and those related to heart failure and cardiac dysfunction, brain natriuretic peptide (BNP) and N-terminal brain natriuretic pro-peptide (NT-proBNP).
View Article and Find Full Text PDFThromb Res
January 2025
Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark; Department of Data, Biostatistics and Pharmacoepidemiology, Centre for Clinical Research and Prevention, Bispebjerg and Frederiksberg Hospital, Denmark.
Background: In patients with pulmonary embolism (PE), the impact of repeated troponin I or T (TnI/TnT) measurements remains unclear.
Methods: Using Danish national registries, we identified PE patients (≥18 years) hospitalized between 2013 and 2018 with initial TnI or TnT measurement within -1/+1 day from admission and >1 repeated measurement within three days. Trajectories of TnI and TnT were identified using latent class trajectory modeling.
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