Histologic Change of the Septal Cartilage with the Respect to Trauma History and Age at the Trauma in Nasal Septal Deviation / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The histologic difference of the traumatic nasal septal cartilage from that of non-traumatic has not been extensively studied. The aim of this study was to identify histologic difference in the nasal septal cartilage between traumatic and non-traumatic nasal septal deviation and to find its implication for surgical intervention. SUBJECTS AND METHOD: Nasal septal cartilage was obtained from 23 patients who had undergone septoplasty or septorhinoplasty for the nasal septal deviation. The septal cartilage without trauma (7 patients, Group I) and with the history of the trauma at the age under 10-15 years old (8 patients, Group II), and over 25 years old (8 patients, Group III) between May 2003 to February 2005 were included in this study. An approximately 1 x 1 cm sized piece of the septal cartilage was harvested from the site deviated the most. The histologic difference of the septal cartilage by hematoxylineosin staining under a light microscope was performed. RESULTS: The chondrocyte densities were significantly higher in the convex side than in the concave side of the septal cartilage in Group I, II, III. Especially, the increased chondrocyte ratio (convex/concave) were more evident in the septal cartilage traumatized at the age of 10 to 15 years, and the cartilage plate was thicker than the other groups (p<0.001). Also, dystrophic changes of the chondrocytes as representing the chondrocyte differentiation and chondroblast ratio (convex/concave) were significantly higher in the group II than in the other groups (p<0.005). CONCLUSION: This study demonstrated that age dependent changes in septal cartilage with nasal trauma showed distinctive histologic characteristics. We suggest that these observations will help determine surgical treatment modality for cases of nasal septal deviations with and without trauma.

iNOS Expression in Inner Ears of Guinea Pigs Injured by PAF / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Platelet-activating factor (PAF) in middle ear effusion is thought to induce hearing loss. The purpose of this study is to determine the effects of PAF placed on round window membrane (RWM) on hearing and cochlear hair cells in guinea pigs, and we also wanted to investigate the role of nitric oxide (NO) in the mechanism of PAF-induced hearing loss by comparing its immunoreactivity to iNOS between the control group and PAF application group. MATERIALS AND METHOD: Guinea pigs were divided into 2 groups: PBS, PAF. The PBS group received phosphate buffered saline (PBS) and the PAF groups received 10, 20, and 40 mug/ml of PAF soaked in gelfoam placed on the RWM. The following three tests were performed on each animal group: hearing was tested with an auditory brainstem response (ABR) test through 24 hours. At the end of 24 hours, cochlear hair cells were examined by scanning electron microscopy (SEM) and immunohistochemistry was carried out on the cochlea to test the expression of inducible nitric oxide (iNOS). RESULTS: The PAF group developed significant elevation of ABR threshold and cochlear hair cell damage in SEM compared with the PBS control group. Strong expression of iNOS on cochlea was observed in the PAF group and lighter expression was seen in PBS group. CONCLUSION: This study demonstrated that PAF placed on the RWM induced hearing loss, and cochlear hair cell damage, and strong iNOS expression in the cochlea. These findings suggest that the PAF-induced hearing loss caused by cochlear hair cell damage may have been mediated by NO. PAF-antagonists and NOS inhibitor may have future therapeutic implications in preventing sensorineural hearing loss associated with chronic otitis media.

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.