[DNA in growing hearts of children. Biochemical and cytophotometric investigations (author's transl)].

In order to clarify the question of an age-dependent polyploidisation of the myocardium during normal cardiac growth, the DNA-content of 39 hearts of infants and children was investigated. After autopsy the total cardiac weights were estimated and thereafter, following the preparation of the hearts, the pure weight of the myocardium (preparation weight) was determined. Using the diphenylamine reaction according to Dische and Burton, the DNA-concentrations and total amounts of DNA in the heart muscle were estimated. The DNA-content of the heart muscle cell nuclei (ploidy classes) was measured cytophotometrically on Feulgen-stained smears of heart muscle cells. DNA measurements were performed on tissue samples from 6-8 different sites of both heart chambers. Growing human hearts of all ages were investigated including 3 fetal hearts and 3 hearts with malformations.