Troponins, cardiac

Troponin C from skeletal sources has four binding sites (406), but cardiac troponin C only three (407) rat annexin V has four binding sites (348), chicken annexin V has three (408). 

Flail, L., Janes, C. and Peddicord, J. A quantitative method for the determination of cardiac Troponin-I for a whole blood immunochemistry analyzer , Clin. Chem., 43, 100 (Abstract) (1997). 

More recent applications comprise, for example, the identification of the binding site of 18 kDa human cardiac troponin C for the drug bepridil [36]. For this study, the unlabeled ligands were bound to selectively [13CH3-Met, Phe-d8]-labeled protein (Fig. 17.8). First, the 13CH3-Met signals of troponin C were easily identified from 13C-HSQC spectra. In a 2D NOESY spectrum with 13C-editing in one dimension, intermolecular NOEs could... 

Fig. 17.8 Intermolecular NOEs between [13CH3-Met, Phe-ds]-labeled cardiac troponin C and the drug bepridil (left panels, drug protein 1.5 1 right panels, 3.5 1). A, D methyl region of the H spectrum B, E HSQC spectra showing the 13CH3-Met signals of the protein C, F section from the NOESY spectrum with 13C-editing in one dimen-...

Wang, F. Li, W. Emmett, M.R. Marshall, A.G. Corson, D. Sykes, B.D. Fourier transform ion cyclotron resonance mass spectrometric detection of small Ca +-induced conformational changes in the regulatory domain of human cardiac troponin C. J. Am. Soc. Mass Spectrom. 1999, 10, 703—710. 

Guo, H., et al. (2005) Development of a low density colorimetric protein array for cardiac troponin I detection. J Nanosci Nanotechnol. 5,2161-6. 

Lindhout, D. A., and Sykes, B. D. (2003). Structure and dynamics of the C-domain of human cardiac troponin C in complex with the inhibitory region of human cardiac troponin l.J Biol. Chem. 278, 27024-27034. 

Takeda, S., Yamashita, A., Maeda, K., and Maeda, Y. (2003). Structure of the core domain of human cardiac troponin in the Ca(2+) -saturated form. Nature 42.1, 35-41. 

Li, M. X., Spyracopoulos, L., and Sykes, B. D. (1999). Binding of cardiac troponin-1147-163 induces a structural opening in human cardiac troponin-C. Biochemistry 38, 8289-8298. 

Palm, T., Graboski, S., Hitchcock-DeGregori, S. E., and Greenfield, N.J. (2001). Disease-causing mutations in cardiac troponin T Identification of a critical tropomyosinbinding region. Biophys.J. 81, 2827-2837. 

Given the understanding that release of cardiac troponin into the circulation reflects myocardial cell death, it is understandable why, clinically, therapies are oriented toward inhibiting the pathophysiologic processes of thrombosis, fibrinolysis, platelet aggregation, and inflammation leading to ischemia and, ultimately, myocardial cell death. Several markers of ischemia have been proposed [2], and research and development studies are underway to adequately validate their clinical usefulness or lack of evidence. These include the topic of this chapter (ischemia-modified albumin [IMA]), as well as choline, unbound free fatty acids, and nourin. 

Of the numerous questions that remain, the most prominent is how clinicians will interpret a positive IMA finding. The positive predictive value of the ACB test seems to be too low for use in ruling in ischemia, a use that clinicians hope the laboratory could provide. It is not known whether patients with negative ECG and necrosis markers (cardiac troponin) and a... 

ACS can be classified into UA, myocardial infarction (Ml) without ST-segment elevation [non-ST-elevation Ml (NSTEMI)], or STEMI. The presence of cardiac troponin in ACS indicates worse prognosis than the absence of troponin (9). 

Hamm CW, Goldmann BU, Heeschen C, et al, Emergency room triage of patients with acute chest pain by means of rapid testing for cardiac troponin T or troponin I, N Engl J Med 1997 337(23) 1648-1653. 

Cardiac enzyme elevation (creatine kinase-MB, cardiac troponin) may occur on average in 20% to 30% of patients after PCI and is associated with adverse clinical outcomes in the short- and long-term (64), Magnetic resonance imaging... 

Table 2 Nonthrombotic causes for elevated cardiac troponin level diagnosis...

Ohtani X Yasunori U, Shimizu M, et al. Association between cardiac troponin T elevation and angioscopic morphology of culprit lesion patients with non-ST segment elevation acute coronary syndromes, Am Heart J 2005 150 227-233. 

I I Jeremias A, Gibson CM, Narrative review alternative causes for elevated cardiac troponin levels when acute coronary syndromes are excluded, Ann Intern Med 2005 142 786-791. 

Sabucedo, A. J. and Furton, K. G. (2003). Estimation of postmortem interval using the protein marker cardiac Troponin I. Forensic Sci. Int. 134,11-16. 

In the last years, the number of publications related to QD-FRET-based systems has increased continuously. In 2008, a FRET-based nanosensor was developed for the rapid detection of human cardiac troponin I, which is a key factor for the early detection of myocardial infarction.96 In this system, a donor(QD)-labeled protein A is bound to an acceptor-labeled capture antibody and the presence of troponin I antigen generates a conformational change within the structure of the antibody. This results in a change of the distance between the donor and acceptor and, therefore, a shift in energy transfer is observed. A limit of detection of 55 nM of troponin in human plasma and a very short time of analysis (1 minute) were reported using this biosensor. 

Takeishi Y, Chu G, Kirkpatrick DL, Wakasaki H, Li Z, Kranias EG, King GL, Walsh RA. 1998. In vivo phosphorylation of cardiac troponin I by PKC 32 decreases cardiomyocyte calcium responsiveness and contractility in transgenic mouse heart. J Clin Invest 102 72-78. 

Cardiac troponin C 18 4.2 0.1 3 4 Cardiac muscle cle contraction Regulation of mus- 47-48... 

Cardiac Troponin Clinical Role in the Diagnosis of Myocardial Infarction... 

Figure 5-1. Time-course of changes in serum cardiac troponin I and creatine kinase MB (CK-MB) following myocardial infarction and subsequent reinfarction during hospitalization. Cardiac-specific troponin I (cTNI), open squares CK-MB, filled circles. Reprinted fromApple and Murakami (2005).

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