Effect of Growth Factors on Hearing Restoration in Deafened Animal Model / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Sensorineural hearing loss is caused by ototoxic drugs, radiation therapy, noise exposure and trauma, etc. They make irreversible changes in cochlear hair cells and degeneration of spiral ganglion neurons. It is known that neurotrophins and other growth factors have an important role in protectingcochlear hair cells and spiral ganglion neurons. We designed this study to analyze the effect of neurotrophins and growth factors delivered to the inner ear of deafened guinea pig. MATERIALS AND METHOD: Healthy 15 guinea pigs with normal Preyer's reflex were chosen, and were made deaf by infusion of kanamycin and ethacrynic acid. Myringotomy was done to both ears, normal saline injected into the left ear, and BDNF (brainderived neurotrophic factor), GDNF (glial cell derived neurotrophic factor), NT-3 (neurotrophin-3), IGF (insulin-like growth factor), EGF (epidermal growth factor), FGF (fibroblast growth factor) were injected in the right ear. RESULTS: Statistically significant hearing gain was obtained up to 35.00+/-13.78 dB in the group 1 (BDNF, GDNF, NT-3 treated group), and up to 34.0+/-5.47 dB in the group 2 (IGF treated group). However, no statistically significant hearing gain was observed in the group 3 (EGF, FGF treated group). CONCLUSION: We observed statistically important improvement of hearing threshold in the BDNF, GDNF, NT-3 treated group and IGF treated group.

Isolation and Culture of Adult Neural Stem Cells from Guinea Pig Tympanic Membrane / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Tympanic membrane perforation is an important clinical problem found in various populations of the world. In large number of cases, acute traumatic perforations heal spontaneously, and in the healing process, stem cells appear to play an important role. However, no studies have been reported regarding somatic stem cells in the tympanic membrane. Herein, we tried to show that guinea pig's tympanic membrane contains cells that display the characteristic features of stem cells. MATERIALS AND METHOD: The tympanic membrane was obtained from the guinea pig. The cells were cultured in a medium with epidermal growth factor (EGF) and fibroblast growth factor (FGF). Proliferating cells were checked with stem cell markers, bromodeoxyuridine (BrdU) and nestin. Differentiated cells from stem cells are checked with betaIII tubulin and S-100. RESULTS: We observed that some of the cultured cells from the tympanic membrane were stained with both stem cell markers, BrdU and nestin. And we observed that these cells differentiated into neuron and gilal cells, which expressed betaIII tubulin and S-100, respectively. CONCLUSION: These results suggest that the tympanic membrane of guinea pigs may have neural stem cells. Further study is needed for finding the origin of stem cells.

Expression of Tonicity-Responsive Enhancer Binding Protein (TonEBP) in the Rat Cochlea: An Immunohistochemical Study / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The inner ear is an organ used for hearing and balance. For its normal function, the inner ear fluid homeostasis is required. There has been controversy over the regulatory mechanisms of maintaining inner ear fluid balance, and they have not yet been clearly defined. TonEBP is the protein that binds tonicity-responsive enhancer elements in the osmoprotective gene, which elevates the compatible osmolytes, which in turn induces cell survival in hypertonic condition. The aim of this study was to elucidate if there is an osmoregulatory mechanism in cochlea. Material and Method: The localization of TonEBP in the cochlea of male Sprague-Dawley rats was studied by immunohistochemistry with an anti rabbit polyclonal anti-rat TonEBP antibody. RESULTS: TonEBP was expressed at outer hair cells, Deiter cells, spiral ligaments, sprial limbus connective tissues, and epithelial lining of basilar membrane facing scala tympani. CONCLUSION: TonEBP in cochlea is one of the proteins involved in elucidating cell survival in changed tonicity during inner ear homeostasis.

Influence of HLA in the Pathogenesis of Meniere's Disease in Korean Population / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: This study was designed to investigate the influence of human leukocyte antigen (HLA) on genetic susceptibility to Meniere's disease and to evaluate the correlation between HLA genotypes and results of examination for various clinical factors of Meniere's disease. MATERIALS AND METHOD: The distribution of HLA class I was examined in 39 patients with MD and 199 healthy controls. For HLA-A and B, the serologic typing was performed according to a standard microlymphocytotoxicity technique. The HLA-C typing was performed by the ARMS-PCR method at DNA level. RESULTS: The frequencies of HLA-CwX0303 (RR=, p<0.02), and CwX0602 (RR=, p<0.03) were significantly increased in patients with Menieres disease, when compared to the controls. However, HLA-B44 (RR=, p<0.004) and CwX0102 (RR=, p<0.03) were significantly decreased in the patients compared to the controls. When an association between hearing level and the presence of HLA alleles was evaluated, the frequencies of HLA-B13 (RR=, p<0.004), CwX0303 (RR=5, p<0.02) and CwX0602 (RR=5, p<0.02) were significantly increased and the frequencies of B44 (RR=1, p*lt;0.02) and CwX0102 (RR=1, p<0.03) were significantly decreased in patients with the state of mild to profound hearing losses, compared to the controls. HLA-B13 showed a different distribution pattern between patients with and without hearing losses. CONCLUSION: These results suggest that some HLA alleles may be useful genetic markers in conferring the susceptibility to Meniere's disease and in implying a prognosis in Korean patients.

A Case of Patent Foramen of Huschke Confirmed during Tympanoplasty / 대한이비인후과학회지

Herniation of the temporomandibular joint (TMJ) into the external auditory canal (EAC) has been reported to occur spontaneously or as a result of trauma, neoplasia, infection, or inflammatory processes. It was postulated that spontaneous herniations were attributable to a patent foramen of Huschke, which represents a non-ossified portion of the tympanic plate. Eight cases of spontaneous herniation of the TMJ into the EAC were reported internationally. Recently, we experienced a case of a patent foramen of Huschke confirmed during a tympanoplasty. We reviewed the intimate relation of the TMJ to the temporal bone as well as the characteristic location, clinical and radiographic findings of a patent foramen of Huschke.