Epithelial changes in or of the middle ear mucoperiosteum. An experimental study

In this study the time necessary for the increase of the secretory cells in the middle ear mucosa was investigated by EM and SEM and by histochemical observation of the secretory cells. The first experiment revealed that a minimum of six to seven days was required for the renewal of the columnar cytoarchitecture after the exposure to silver protein solution. In the next experiment 35 guinea pigs were subjected to tubal obstruction. Columnar metaplasia was found in one case sacrificed after the third month, and gland formations without myoepithelial cells and nerve endings were seen in those after the fourth month. In an additional experiment, since the frontal sinus of the dogs is simple and pneumatized, duct obstruction was performed. Slight epithelial change and accumulation of glue-like thick mucus, which was negative in culture, was found in all four cases after three months. In one of the two cases with obstruction for four months, typical exophthalmus in the pseduostratified epithelium with an increase in secretory cells or cuboidal epithelium with nonciliated cells was demonstrated.