Electron microscopic X-ray microanalysis of localized element concentrations in human cardiomyopathies: a pilot study

The elemental content in localized cellular regions of human myocardial biopsy specimens was studied by electron microscopic x-ray microanalysis. The elements detected were phosphorus, sulfur, chlorine, calcium, and zinc and occasionally tracrs of iron and copper. Nucleoli and heterochromatin contained the highest concentrations of phosphorus and calcium, whereas sulfur was prominent in sarcomeres, dark mitochondria, and secondary lysosomes. Dark mitochondria often had more phosphorus, sulfur, and calcium than swollen, paler ones.