X-ray microanalysis of mast cells in rat's muscle

Radiation effects on mast cells: secretory ability, histamine release and recovery, and cell number

We studied the effects of irradiation with a single fraction of high-energy electrons, in the absorbed dose range used in radiotherapy, on features related to the rat mesenteric mast-cell (MC) population. Such features were energy dispersive X-ray microanalysis for zinc, light and transmission electron microscopic changes, histamine content, and secretory ability of MCs when exposed to the potent secretagogue 48/80. The observation period was 14 days. Also studied were the effects of radiation on the number and histamine content of free peritoneal MCs. Irradiation-induced decrease in histamine content was delayed for at least two days and the rate of subsequent recovery of mesenteric histamine was approximately 70% below normal. This was corroborated by the findings of necrotic and fragmented mesenteric MCs during the entire experimental period. Fibroblasts and macrophages phagocytosed groups of MC granules as well as individual MC granules. A fraction of the extruded MC granules retained an almost normal appearance. This suggests that they were solubilized unduly slow presumably because the irradiation destroyed the mechanisms and enzymes which normally degrade the heparin-protein granule matrix and its heparin. Moreover, the irradiation suppressed the secretory ability of mesenteric MCs and significantly reduced the number of free peritoneal MCs. The findings indicate that the MC is a remarkably radiosensitive connective-tissue cell.

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.