scholarly journals Studies towards hcTnI Immunodetection Using Electrochemical Approaches Based on Magnetic Microbeads

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2457 ◽  
Author(s):  
Alejandro Hernández-Albors ◽  
Gloria Colom ◽  
J.-Pablo Salvador ◽  
M.-Pilar Marco
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Gold Standard ◽  
Cardiac Troponin ◽  
Magnetic Beads ◽  
Troponin I ◽  
Magnetic Microbeads ◽  
Specific Antibodies ◽  
Paramagnetic Beads ◽  
European Society Of Cardiology

Different electrochemical strategies based on the use of magnetic beads are described in this work for the detection of human cardiac troponin I (hcTnI). hcTnI is also known as the gold standard for acute myocardial infarction (AMI) diagnosis according to the different guidelines from the European Society of Cardiology (ESC) and the American College of Cardiology (ACC). Amperometric and voltamperometric sandwich magnetoimmunoassays were developed by biofunctionalization of paramagnetic beads with specific antibodies. These bioconjugates were combined with biotinylated antibodies as detection antibodies, with the aim of testing different electrochemical transduction principles. Streptavidin labeled with horseradish peroxidase was used for the amperometric magnetoimmunoassay, reaching a detectability of 0.005 ± 0.002 µg mL−1 in 30 min. Cadmium quantum dots-streptavidin bioconjugates were used in the case of the voltamperometric immunosensor reaching a detectability of 0.023 ± 0.014 µg mL−1.

Abstract 2425: Absence of Auto-Antibodies against Cardiac Troponin I Predicts Improvement of Left Ventricular Function after Acute Myocardial Infarction

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Florian Leuschner ◽  
Jin Li ◽  
Stefan Göser ◽  
Lars Reinhardt ◽  
Renate Öttl ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Stroke Volume ◽  
Antibody Titer ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Cardiac Troponin I ◽  
Igg Antibody ◽  
Follow Up Study

Application of antibodies against cardiac troponin I (cTnI-Ab) can induce dilation and dysfunction of the heart in mice. Recently, we demonstrated that immunization with cTnI induces inflammation and fibrosis in myocardium of mice. Others have shown that autoanti-bodies to cTnI are present in patients with acute coronary syndrome. But little is known about the clinical relevance of detected cTnI-Ab. First, anti-cTnI and anti-cTnT antibody titers were measured in sera from 272 patients with dilated- (DCM) and 185 with ischemic- (ICM) cardiomyopathy. Secondly, 108 patients with acute myocardial infarction (AMI) were included for a follow-up study. Heart characteristics were determined by magnetic resonance imaging 4 days and 6 –9 months after AMI. Altogether, in 7,0% of patients with DCM and in 9,2% with ICM an anti-cTnI IgG antibody titer ≥1:160 was measured. In contrast, only in 1,7% of patients with DCM and in 0,5% with ICM an anti-cTnT IgG antibody titer ≥1:160 was detected. Ten out of 108 patients included in the follow-up study were tested positive for cTnI-Ab with IgG Ab titers ≥1:160. TnI-Ab negative patients showed a significant increase in LVEF and stroke volume 6 –9 months after AMI. In contrast, there was no significant increase in LVEF and stroke volume in TnI-Ab positive patients. We demonstrate for the first time that the prevalence of cTnI-Abs in patients with AMI has an impact on the improvement of the LVEF over a study period of 6 –9 months.

scholarly journals Troponin: the biomarker of choice for the detection of cardiac injury

2005 ◽  
pp. 1191-1202
Author(s):  
Luciano Babuin ◽  
Allan S. Jaffe
Keyword(s):  
Myocardial Infarction ◽  
Cardiovascular Disease ◽  
Acute Myocardial Infarction ◽  
Troponin I ◽  
Cardiac Injury ◽  
Transaminase Activity ◽  
Elevated Troponin ◽  
Critical Issues ◽  
European Society Of Cardiology

It has been known for 50 years that transaminase activity increases in patients with acute myocardial infarction. With the development of creatine kinase (CK), biomarkers of cardiac injury began to take a major role in the diagnosis and management of patients with acute cardiovascular disease. In 2000 the European Society of Cardiology and the American College of Cardiology recognized the pivotal role of biomarkers and made elevations in their levels the “cornerstone” of diagnosis of acute myocardial infarction. At that time, they also acknowledged that cardiac troponin I and T had supplanted CK-MB as the analytes of choice for diagnosis. In this review, we discuss the science underlying the use of troponin biomarkers, how to interpret troponin values properly and how to apply these measurements to patients who present with possible cardiovascular disease. Troponin is the biomarker of choice for the detection of cardiac injury. To use it properly, one must understand how sensitive the specific assay being used is for detecting cardiac injury, the fact that elevated troponin levels are highly specific for cardiac injury and some critical issues related to the basic science of the protein and its measurement. In this article, we review the biology of troponin, characteristics of assays that measure serum troponin levels and how to apply these measurements to patients who present with possible cardiovascular disease. We also discuss other clinical situations in which troponin levels may be elevated.

scholarly journals Characterization of cardiac troponin subunit release into serum after acute myocardial infarction and comparison of assays for troponin T and I

1998 ◽  
Vol 44 (6) ◽  
pp. 1198-1208 ◽  
Author(s):  
Alan H B Wu ◽  
Yue-Jin Feng ◽  
Robert Moore ◽  
Fred S Apple ◽  
Paul H McPherson ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Cross Reactivity ◽  
Binary Complex ◽  
Serum Samples ◽  
Binary And Ternary Complexes ◽  
The Cross

Abstract We examined the release of cardiac troponin T (cTnT) and I (cTnI) into the blood of patients after acute myocardial infarction (AMI). Three postAMI serum samples were applied in separate analytical runs onto a calibrated gel filtration column (Sephacryl S-200), and the proteins were separated by molecular weight. Using commercial cTnT and cTnI assays measured on collected fractions, we found that troponin was released into blood as a ternary complex of cTnT-I-C, a binary complex of cTnI-C, and free cTnT, with no free cTnI within the limits of the analytical methodologies. The serum samples were also examined after incubation with EDTA and heparin. EDTA broke up troponin complexes into individual subunits, whereas heparin had no effect on the assays tested. We added free cTnC subunits to 24 AMI serum samples and found no marked increase in the total cTnI concentrations, using an immunoassay that gave higher values for the cTnI-C complex than free cTnI. To characterize the cross-reactivity of cTnT and cTnI assays, purified troponin standards in nine different forms were prepared, added to serum and plasma pools, and tested in nine quantitative commercial and pre-market assays for cTnI and one approved assay for cTnT. All nine cTnI assays recognized each of the troponin I forms (complexed and free). In five of these assays, the relative responses for cTnI were nearly equimolar. For the remainder, the response was substantially greater for complexed cTnI than for free cTnI. Moreover, there was a substantial difference in the absolute concentration of results between cTnI assays. The commercial cTnT assay recognized binary and ternary complexes of troponin on a near equimolar basis. We conclude that all assays are useful for detection of cardiac injury. However, there are differences in absolute cTnI results due to a lack of mass standardization and heterogeneity in the cross-reactivities of antibodies to various troponin I forms.

Comparable detection of acute myocardial infarction by creatine kinase MB isoenzyme and cardiac troponin I

1994 ◽  
Vol 40 (7) ◽  
pp. 1291-1295 ◽  
Author(s):  
J E Adams ◽  
K B Schechtman ◽  
Y Landt ◽  
J H Ladenson ◽  
A S Jaffe
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Creatine Kinase ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Characteristic Curve ◽  
Cardiac Injury ◽  
Cardiac Troponin I ◽  
Creatine Kinase Mb ◽  
Coronary Care

Abstract Although measurement of cardiac troponin I (cTnI) is, in some situations, more specific for detection of cardiac injury than is measurement of the MB isoenzyme of creatine kinase (MBCK), its sensitivity and specificity relative to MBCK for detection of myocardial infarction has not been established. Accordingly, we studied prospectively 199 consecutive patients admitted to the coronary care unit. Values of MBCK and cTnI mass were determined in all samples. Of the 188 patients admitted with a suspicion of acute myocardial ischemia, 89 were diagnosed as having an acute myocardial infarction on the basis of the patterns of MBCK values. Eighty-six of these patients also had increased cTnI (concordance, 96.6%); three did not. Of the patients diagnosed as without infarction, five with unstable angina and symptoms in the day(s) prior to admission had increased cTnI, for a cTnI specificity of 94.9%. Receiver operating characteristic curve analysis indicated that cTnI and MBCK had statistically indistinguishable diagnostic accuracies for the detection of acute myocardial infarction.

Myoglobin, creatine kinase MB, and cardiac troponin-I to assess reperfusion after thrombolysis for acute myocardial infarction: Results from TIMI 10A

1997 ◽  
Vol 134 (4) ◽  
pp. 622-630 ◽  
Author(s):  
Milenko J. Tanasijevic ◽  
Christopher P. Cannon ◽  
Donald R. Wybenga ◽  
George A. Fischer ◽  
Christine Grudzien ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Creatine Kinase ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Cardiac Troponin I ◽  
Creatine Kinase Mb

scholarly journals Evaluation of a New Assay for Cardiac Troponin I vs Creatine Kinase-MB for the Diagnosis of Acute Myocardial Infarction

1997 ◽  
Vol 4 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Gerard X. Brogan ◽  
Judd E. Hollander ◽  
Charles F. McCuskey ◽  
Henry C. Thode ◽  
Jeffrey Snow ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Creatine Kinase ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Cardiac Troponin I ◽  
Creatine Kinase Mb

scholarly journals Troponin I is released in bloodstream of patients with acute myocardial infarction not in free form but as complex

1997 ◽  
Vol 43 (8) ◽  
pp. 1379-1385 ◽  
Author(s):  
Aleksei G Katrukha ◽  
Anastasia V Bereznikova ◽  
Tatiana V Esakova ◽  
Kim Pettersson ◽  
Timo Lövgren ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Monoclonal Antibodies ◽  
Cardiac Troponin ◽  
Main Part ◽  
Troponin I ◽  
Complex Form ◽  
Immunofluorescence Assay ◽  
Assay Development ◽  
Free Form

Abstract Fourteen monoclonal antibodies (mAbs) against human cardiac troponin I (cTnI) were generated by commonly used experimental techniques. All these antibodies, as well as antibody 414 (HyTest), were specific for human cTnI. Fifteen antibodies thus obtained were tested in a sandwich cTnI immunofluorescence assay (altogether 196 combinations). Ten pairs giving the highest sensitivity were selected for further investigation. The effect of TnI–TnC complex formation on antibody interaction with antigen was analyzed. The formation of TnI–TnC complex results in a significant decrease of the interaction of mAbs with TnI for seven of 10 analyzed pairs of antibodies. Using two pairs of cTnI-specific mAbs, one that recognized only free cTnI but not cTnI complexed with cTnC, and another that could be used for measurement of total cTnI (free cTnI and cTnI in complex with cTnC), we demonstrated that the main part of cTnI in serum collected from acute myocardial infarction patients is presented in the complex form. We concluded that effective and reliable immunological detection of TnI is possible only when antibodies used for assay development recognize both free TnI and TnI complexed with other troponin components.

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