Clinical Analysis of the Laryngeal Leukoplakia / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Leukoplakia is a descriptive term designating a white patch or plaque of the mucosa and must be complemented by histology. The aim of this study was to analyze the laryngeal leukoplakia clinically. MATERIALS AND METHOD: 48 patients were included from 1995 to 2001. All presented themselves with laryngeal leukoplakia in telescopic examination. The available medical record are age, sex, duration of smoking, histopathological finding, treatment and follow up result. RESULTS: The patients were composed of 46 males and 2 females. There were 7 patients (15%) with specific diagnostic lesion (polyps, lymphoma, tuberculosis, chronic inflammation and papilloma), 19 patients (40%) with simple hyperplasia or hyperkeratosis, 4 patients (8%) with mild dysplasia, 2 patients (4%) with moderate dysplasia, 2 patients (4%) with severe dysplasia, 2 patients (4%) with carcinoma in situ, and 1 patient (2%) with microinvasive carcinoma and 11 patients with invasive squamous cell carcinoma. Rebiopsy was performed to 10 cases during follow up period. CONCLUSION: The results of our study show that the leukoplakia was presented in 15% of all cases with specific diagnostic lesion and that the patient was treated according to their specific diagnosis. Almost all of the case with precancerous conditions were cured with cord stripping, cordectomy or radiation therapy.

Evaluation and Prevention of Gentamicin-induced Vestibulotoxicity in Rabbits Using Off-Vertical Axis Rotation / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purposes of this study was to investigate the characteristics of gentamicin-induced vestibulotoxicity of s otolith organs by assessing the results of earth vertical and the off-vertical axis rotation tests with a morphologic study. MATERIALS AND METHODS: Rabbits were grouped into two groups, ototoxic and ototoxic prevention group. Vestibulotoxicity was induced by injecting gentamicin (GM) into the peritoneum. Prevention of the vestibulotoxicity was studied by injecting NMDA receptor inhibitors (MK-801), iron chelating agents (deferoxamine) peritonially, and osmotic pumps filled with neurotrophic factors (GDNF, BDNF), respectively. The animal rotation system was designed to rotate the animal sinusoidally or in velocity step (constant velocity) rotation. Off-vertical rotation was applied to evaluate the otolithic function. Scanning electron microscopy were examined for the structural changes of the otolithic organs. RESULTS AND CONCLUSIONS: GM-induced vestibulotoxicity was confirmed by gain decreasing in the earth vertical SHA rotation test and bias decreasing in the off-vertical rotation test. However, changes in modulation was not definite. Bilateral prevention of GM-induced vestibulotoxicity was confirmed by systemic injection of deferoxamine and MK-801, and characteristics of unilateral prevention was confirmed by local application of the neurotrophic factors using osmotic pumps. In the SEM study, the GM-induced hair cell damages of the vestibule were identified, which was prevented by the preventive drugs. The reduction of bias value without change of modulation was comparable with the reduction of gain in the earth vertical axis rotation after GM-induced vestibulotoxicity.