[Myocardial regulatory proteins in children with congenital heart defects].

The purpose of this study was to compare the protein profiling of the regulatory proteins. The samples of myocardial tissue were obtained during surgical intervention from children (age 8.2 +/- 1.8 years) operated for different types of congenital heart diseases. The arterial oxygen saturation was 95.5 +/- 0.07% in normoxaemic patients (ventricular and atrial septal defects), resp. 76.9 +/- 2.1% in hypoxaemic patients (tetralogy of Fallot). The both cytosolic and myofibrillar fractions of cardiac troponin T (cTnT) were isolated by stepwise extraction (4) from the both right ventricular and right atrial musculature. The concentration of proteins was measured using Coomasie Plus Protein Reagent Kit (Pierce). After isolation, one-dimensional SDS polyacrylamide gel electrophoresis was carried out according to a modified version of the method of Laemmli (1970), using a 12% separating gel and a 4% stacking gel. In some cases after SDS-PAGE, proteins were electroblotted onto nitrocellulose membrane for immunoblotting and analysed using the JLT-12 monoclonal antibodies (Sigma Chemicals). The cytosolic pool of cTnT (measured by commercial kit Elecsys Troponin T STAT Immunoassay--Roche) represents about 12.5%, the myofibrillar pool of cTnT was about 87.5%; hypoxaemia did not affect this proportion.