TYMPANOSCLEROSIS - ELECTRON MICROSCOPIC STUDY

A light-microscopic study revealed the proliferation of collagen fibers, hyaline degeneration and dark-blue in HE-staining in the sclerotic masses. At the above-mentioned site the following findings are obtained through an electron microscope. (1) Degenerating mitochondria with electron-dense masses in fibrocyte-like cell. (2) Electron-dense cell stroma, so-called autophaged lysosome and membrane-bound fragments in fibrocyte-like cells or among the collagen bundles. (3) Close to or near the cell membrane numerous collagen fibers with electron-dense material. This fact was regarded as newly produced fibers in fibroblast after calcification has taken place. (4) By X-ray microanalysis in electron microscope, these electron-dense materials were proved as calcium-phosphate crystals-probably apatite clusters. (5) X-ray microanalysis showed that intracellular electron-dense material contained more calcium than phosphate, whereas extracellular electron-dense plaque contained more phosphate than calcium. From this we may conclude that it is uncertain whether hypercalcinosis is in the extracellular fluid. (6) Various other substances Fe, Cl, Cu, Mg, Cr, Mn. (7) The shapes of apatite clusters are doughnut-like, of the form of an annual ring, or tortoise-shell pattern. (8) Animal examination showed that hyperparathyroidism caused calcification of tympanosclerosis. © 1969 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.