Nasopharyngeal exposure to simulated gastric juice causes eustachian tube dysfunction in rats. Specifically, middle ear pressure regulation and mucociliary clearance of middle ear contents were disabled. These results support recent reports in the literature linking nasopharyngeal reflux to eustachian tube dysfunction and secondary development of otitis media.

Thickening of the basement membrane in capillaries is implicated in the microangiopathic complications of diabetes mellitus. This study was designed to evaluate microangiopathic changes of the inner ear associated with insulin-dependent diabetes mellitus (IDDM) and concurrent moderate-intensity noise exposure. Male Sprague-Dawley rats were injected with streptozotocin (65 mg/kg) to induce IDDM. Half of the control and diabetic animals were exposed to chronic noise of 95 dB over the 6-month study period. Photomicrographs of the capillaries in the stria vascularis were obtained by transmission electron microscopy, and basement-membrane thickness was measured with an image processing system. This study quantitatively demonstrates basement-membrane thickening consistent with diabetic microangiopathy in the inner ear of IDDM rats. Noise exposure did not significantly change basement-membrane thickness in either diabetic or control animals.

No abstract

No abstract

No abstract