Intoxication with high doses of the aminoglycoside antibiotic amikacin in a supranormal sensitive period in the rat induces complete destruction of the inner and outer hair cells in the organ of Corti in all turns, whereas the supporting cells remain partially preserved in the upper turns. With increasing survival time, the number of ganglion cells in the spiral ganglion decreases progressively, reaching a minimum of about 10% surviving cells after 12 months. Both type I and type II neurons are subject to retrograde degeneration, although type-II cells degenerate more slowly than type-I cells. The presence or absence of supporting cells in the organ of Corti does not seem to influence neuronal degeneration. This retrograde degeneration is similar in all animals so far studied but its time course is different from different species. Retrograde degeneration after destruction of Corti's organ is a long-lasting process and is never completed at once. This must be taken into consideration in the treatment of total deafness with electric stimulation of surviving neurons.
Sound exposures of more than 130 dB lead to typical tears in the basilar membrane in the area of maximal damage. The position, size, and number of these tears are evaluated.
Twenty-one patients with advanced previously untreated squamous cell carcinoma of the oral cavity, oro- and hypopharynx and supraglottic region were treated with combined cis-platinum-methotrexate-bleomycin chemotherapy. Methotrexate (20 mg/m2) was given on day 1, after prehydration cis-diaminodichloroplatinum (60 mg/m2) was given with mannitol diuresis on day 2. From day 3 until day 8 15 mg bleomycin was given daily in a 6-h infusion. Three courses were given every 3 weeks. After clinical evaluation for tumor response all patients were operated and underwent postoperative radiotherapy. After induction chemotherapy eight patients (39%) had a complete, five (24%) a partial (shrinkage of measurable disease more than 50%), and seven (33%) a minor response (more than 25% but less than 50% tumor shrinkage). The neoplasms of the oral cavity and the pharynx responded better than the laryngeal primaries. Exophytic tumors responded better to chemotherapy than the endophytic tumors. Histopathologic examination in serial sections demonstrates in all cases--even after clinically complete response--some small rests of tumor in local fibrotic tissue often underneath a regrown mucosal epithelium.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.