Myocardial DNA content, ploidy level and cell number in geriatric hearts: post-mortem examinations of XXXX myocardium in old age.

@entity1 @entity82 @entity101 @entity1184 @entity1283 @entity1373 @entity194 @entity299 @entity2057 @entity4288
A reduced adaptation rate of the myocardium must, in many cases, be made responsible for @entity299 of old @entity1 . The present investigations are aimed towards the question whether heart in old age is accompanied by a loss of myocardial cells and whether a polyploidisation of @entity2057 takes place thus indicating an adaptive process. A total of 40 @entity1 hearts obtained from autopsy material were studied, among them 30 geriatric hearts. Following preparation of the hearts, the myocardium was weighed and the total amount of DNA was determined biochemically. By means of Feulgen cytophotometry the ploidy levels of the heart muscle nuclei were detected. We have used a special method for estimating the total number of @entity2057 and connective tissue cells in the individual hearts. It could be shown that the total amount of DNA in the myocardium is correlated with the myocardial weight and not with the age of the individual. Instead, DNA synthesis occurs in the @entity2057 of all age groups depending on the functional activity of the heart. The degree of polyploidisation is closely correlated with @entity1283 without any influence of age. In @entity1184 hearts the number of connective tissue cells increases from normally 4 to 5 X 10(9) to 12 X 10(9) (in hearts weighing more than 700 g); in hearts with @entity82 these values are even higher. In normal hearts 1.8 to 2.1 X 10(9) @entity2057 can be estimated; in hearts weighing more than 500 g numerical @entity1373 of the @entity2057 is produced, reaching a maximum number of 4.8 X 10(9) muscle cells in excessively @entity1184 hearts weighing more than 800 g. No correlation between age and myocardial cell number (i.e. @entity2057 or connective tissue cells) could be observed. This means that no agespecific changes occur in the myocardium with regard to the DNA content and cell number. The structural changes found in the hearts of old individuals are produced by extracardial influences (i.e. @entity4288 , @entity101 , etc.) leading to @entity1283 . Polyploidisation and augmentation of @entity2057 in @entity1283 or decrease in the number of @entity2057 in heart @entity194 may occur at any time of life and are not age-specific.
