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001-es BibID:	BIBFORM005631
Első szerző:	Hamdani, Nazha
Cím:	Myofilament dysfunction in cardiac disease from mice to men / Hamdani, N., de Waard, M., Messer, A. E., Boontje, N. M., Kooij, V., van Dijk, S., Versteilen, A., Lamberts, R., Merkus, D., Dos Remedios, C., Duncker, D. J., Borbely, A., Papp, Z., Paulus, W., Stienen, G. J. M., Marston, S. B., van der Velden, J.
Dátum:	2008
ISSN:	0142-4319 (Print)
Megjegyzések:	In healthy human myocardium a tight balance exists between receptor-mediated kinases and phosphatases coordinating phosphorylation of regulatory proteins involved in cardiomyocyte contractility. During heart failure, when neurohumoral stimulation increases to compensate for reduced cardiac pump function, this balance is perturbed. The imbalance between kinases and phosphatases upon chronic neurohumoral stimulation is detrimental and initiates cardiac remodelling, and phosphorylation changes of regulatory proteins, which impair cardiomyocyte function. The main signalling pathway involved in enhanced cardiomyocyte contractility during increased cardiac load is the beta-adrenergic signalling route, which becomes desensitized upon chronic stimulation. At the myofilament level, activation of protein kinase A (PKA), the down-stream kinase of the beta-adrenergic receptors (beta-AR), phosphorylates troponin I, myosin binding protein C and titin, which all exert differential effects on myofilament function. As a consequence of beta-AR down-regulation and desensitization, phosphorylation of the PKA-target proteins within the cardiomyocyte may be decreased and alter myofilament function. Here we discuss involvement of altered PKA-mediated myofilament protein phosphorylation in different animal and human studies, and discuss the roles of troponin I, myosin binding protein C and titin in regulating myofilament dysfunction in cardiac disease. Data from the different animal and human studies emphasize the importance of careful biopsy procurement, and the need to investigate localization of kinases and phosphatases within the cardiomyocyte, in particular their co-localization with cardiac myofilaments upon receptor stimulation.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Muscle Research and Cell Motility. - 29 : 6-8 (2008), p. 189-201. -
További szerzők:	de Waard, Monique Messer, Andrew E. Boontje, Nicky M. Kooij, Viola Dijk, Sabine, van Versteilen, Amanda Lamberts, Regis Merkus, Daphne Dos Remedios, Cris Duncker, Dirk J. Borbély Attila (1978-) (kardiológus) Papp Zoltán (1965-) (kardiológus, élettanász) Paulus, Walter J. Stienen, Ger J. M. Marston, Steven B. Velden, Jolanda, van der
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001-es BibID:	BIBFORM030905
Első szerző:	Papp Zoltán (kardiológus, élettanász)
Cím:	Effects of Ca2+-sensitizers in permeabilized cardiac myocytes from donor and end-stage failing human hearts / Papp Z., van Der Velden J., Borbély A., Édes I., Stienen G. J. M.
Dátum:	2004
Megjegyzések:	During heart failure, alterations occur in contractile protein expression and phosphorylation, which may influence the effects of Ca2+ -sensitizers. To quantify the magnitude of these effects, isometric force was studied in mechanically isolated Triton-skinned myocytes from end-stage failing and non-failing donor hearts under control conditions (pH 7.2; no added inorganic phosphate (Pi)) and under mimicked ischemic conditions (pH 6.5; 10 mM Pi). Two different Ca2+ -sensitizers were used: EMD 53998 (10 microM), which exerts its influence through the actin-myosin interaction, and OR-1896 (10 microM) (the active metabolite of levosimendan), which affects the Ca2+ -sensory function of the thin filaments. The maximal force (Po) measured at saturating Ca2+ concentration and the resting force (Prest) determined in the virtual absence of Ca2+ (pCa 9) did not differ between the failing and non-failing myocytes, but the Ca2+ concentration required to induce the half-maximal force under control conditions was significantly lower in the failing than in the non-failing myocytes (DeltapCa50=0.15). This difference in Ca2+ -sensitivity, however, was abolished during mimicked ischemia. EMD 53998 increased Po and Prest by approximately 15% of Po and greatly enhanced the Ca2+ -sensitivity (DeltapCa50 > 0.25) of force production. OR-1896 did not affect Po and Prest, and provoked a small, but significant Ca2+ -sensitization (DeltapCa50 approximately 0.1). All of these effects were comparable in the donor and failing myocytes, but, in contrast with OR-1896, EMD 53998 considerably diminished the difference in the Ca2+ -sensitivities between the failing and non-failing myocytes. The action of Ca2+ -sensitizers under mimicked ischemic conditions was impaired to a similar degree in the donor and the failing myocytes. Our results indicate that the Ca2+ -activation of the myofibrillar system is altered in end-stage human heart failure. This modulates the effects of Ca2+ -sensitizers both under control and under mimicked ischemic conditions.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Muscle Research and Cell Motility. - 25 : 3 (2004), p. 219-224. -
További szerzők:	Velden, Jolanda, van der Borbély Attila (1978-) (kardiológus) Édes István (1952-) (kardiológus) Stienen, Ger J. M.
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