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Isometric tension development and its calcium sensitivity in skinned myocyte-sized preparations from different regions of the human heart.
van der Velden, J; Klein, L J; van der Bijl, M; Huybregts, M A; Stooker, W; Witkop, J; Eijsman, L; Visser, C A; Visser, F C; Stienen, G J.
Afiliación
  • van der Velden J; Laboratory for Physiology, Free University, Amsterdam, Netherlands. J.van_der_Velden.physiol@med.vu.nl
Cardiovasc Res ; 42(3): 706-19, 1999 Jun.
Article en En | MEDLINE | ID: mdl-10533611
ABSTRACT

OBJECTIVE:

In this study we investigated whether differences exist or develop in patients with aortic or mitral valve disease in myofibrillar contractile function and contractile protein composition between subendo- and subepicardial human ventricular tissue. Isometric tension, its calcium sensitivity and contractile protein composition were studied in left ventricular subendo- and subepicardial and in atrial biopsies obtained during open heart surgery from 24 patients with mitral or aortic valve disease.

METHODS:

Isometric tension was measured in mechanically isolated skinned myocyte-sized preparations at different free calcium concentrations at 15 degrees C. Protein composition was analysed by one-dimensional gel electrophoresis. A comparison was made between the results of subendo- and subepicardial ventricular tissue within each New York Heart Association class and within the different hemodynamically overloaded groups.

RESULTS:

Maximal isometric tension was significantly lower in atrial than in ventricular preparations. The concentration of calcium required for half-maximal activation was significantly higher in atrial than in ventricular preparations. Within the ventricle no differences were found in contractile protein composition, isometric tension and its calcium sensitivity between subendo- and subepicardial tissue when all patients were treated as one group or when patients were subdivided according to severity of heart disease or hemodynamic overload.

CONCLUSIONS:

In this group of patients with ventricular volume or pressure overload no regional differences exist or develop during cardiac disease in left ventricular myofibrillar protein composition and force production. Maximal isometric tension and its calcium sensitivity are smaller in atrial than in ventricular preparations.
Asunto(s)
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Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Calcio / Enfermedades de las Válvulas Cardíacas / Contracción Isométrica / Contracción Miocárdica Tipo de estudio: Diagnostic_studies / Prognostic_studies Límite: Female / Humans / Male Idioma: En Revista: Cardiovasc Res Año: 1999 Tipo del documento: Article País de afiliación: Países Bajos
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Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Calcio / Enfermedades de las Válvulas Cardíacas / Contracción Isométrica / Contracción Miocárdica Tipo de estudio: Diagnostic_studies / Prognostic_studies Límite: Female / Humans / Male Idioma: En Revista: Cardiovasc Res Año: 1999 Tipo del documento: Article País de afiliación: Países Bajos