The biochemical composition of tympanosclerotic deposits.

We have studied the quantitative analysis of calcium, phosphate and cholesterol in the tympanosclerotic plaques removed from 25 patients. Our findings confirm that tympanosclerosis has a partly calcified organic matrix, in which the calcification process is probably similar in its qualitative chemical structure to that occurring in other calcified pathological tissues. The degree of calcification varies from one case to another and is even different in various locations of the same sampling. However, calcium levels are usually lower than in other pathological tissues which are calcified. The average quantity of calcium in our studies was 2 mg in 100 mg tissue or 12 mg in 100 mg protein. The average molar ratio between calcium and phosphate was 3, corresponding to the hydroxyapatite ratio. The average total quantity of cholesterol present was only 15 micrograms in 100 mg protein.