Hee-Nam Kim

Compositional Difference in Middle Ear Effusion: Mucous Versus Serous†

Objectives Serous otitis media is usually responsive to medical treatment, whereas mucoid otitis media is not. The present study was undertaken to elucidate the compositional difference between serous and mucoid effusion and to investigate whether MUC5AC acts as a major mucin in the middle ear mucosa with mucoid otitis media.

Ciliary and Secretory Differentiation of Normal Human Middle Ear Epithelial Cells

Recent technical advances now permit the serial culture of normal human middle ear epithelial (NHMEE) cells. However, the ciliary differentiation of these cells has not been achieved. The purpose of this study was to establish a culture system in order to differentiate serially cultured NHMEE cells into ciliated cells. If ciliated cells developed, the percentages of ciliated cells and secretory cells were measured throughout the duration of culture. We also examined the levels of mucin and lysozyme secretion and their mRNAs in a time-dependent manner. Human middle ear mucosa with a normal appearance was harvested and serially cultured after enzymatic disaggregation. These cells were cultured in an air-liquid interface (ALI) culture system for 2, 7, 14, 21 and 28 days after confluence. Ciliogenesis usually began 16-18 days after confluence. The percentage of ciliated cells detected by means of immunohistochemical staining increased over time up to a maximum of 10.6% but the percentage of secretory cells remained stable at 40% throughout the duration of culture. By Day 14 after confluence, the amounts of mucin and lysozyme secretion, as measured by dot-blotting analysis, had increased significantly and then remained stable. The expression levels of mucin gene 5B ( MUC5B ), MUC8 and lysozyme increased with the duration of culture. MUC8 in particular showed a dramatic increase on Day 28 after confluence. In contrast, the level of MUC5AC mRNA peaked on Day 14 after confluence, and then decreased. In conclusion, ciliary differentiation of NHMEE cells can be induced using an ALI culture system. Our study also suggests that secretory function develops earlier than ciliogenesis, and that the expressions of MUC5B and MUC8 mRNAs increase as a function of differentiation.

Effects of Retinoic Acid, Triiodothyronine and Hydrocortisone on Mucin and Lysozyme Expression in Cultured Human Middle Ear Epithelial Cells

Mucous hypersecretion is a major complication of otitis media and can prolong the disease course and increase morbidity. Mucin, a major component of mucus, is a macromolecular complex of glycoprotein and makes mucus viscous. Lysozyme is a secretory element of the middle ear mucosa, which has a non-specific and innate antibacterial function. We attempted to identify factors that regulate these secretory products and their morphological phenotype using cultured human middle ear epithelial cells. Cellular differentiation was induced by creating an air-liquid interface on culture day 9 in serum-free conditioned media. Omission of retinoic acid (RA) caused decrease in the secretion of mucin and lysozyme, and in the cellular expression of MUC 2, MUC 5AC and MUC 5B mRNA. In contrast, removal of triiodothyronine (T3) caused an increase in the secretion of mucin and the level of MUC5AC mRNA. When hydrocortisone (HC) was removed from the media, the secretion of mucin was decreased without an apparent change of message level. The expression of MUC 1 mRNA was not changed by the respective deficiency of RA, T3 or HC. The effect of T3 or HC on lysozyme was not significant. This study shows that RA, T3 and HC influence the morphological phenotype and the secretory function of mucin and lysozyme in cultured human middle ear epithelial cells. This culture system can serve as an in vitro model for study of the regulation of various cellular secretions in human middle ear epithelium.Mucous hypersecretion is a major complication of otitis media and can prolong the disease course and increase morbidity. Mucin, a major component of mucus, is a macromolecular complex of glycoprotein and makes mucus viscous. Lysozyme is a secretory element of the middle ear mucosa. which has a non-specific and innate antibacterial function. We attempted to identify factors that regulate these secretory products and their morphological phenotype using cultured human middle ear epithelial cells. Cellular differentiation was induced by creating an air liquid interface on culture day 9 in serum-free conditioned media. Omission of retinoic acid (RA) caused decrease in the secretion of mucin and lysozyme, and in the cellular expression of MUC 2, MUC 5AC and MUC 5B mRNA. In contrast, removal of triiodothyronine (T3) caused an increase in the secretion of mucin and the level of MUC5AC mRNA. When hydrocortisone (HC) was removed from the media, the secretion of mucin was decreased with out an apparent change of message level. The expression of MUC 1 mRNA was not changed by the respective deficiency of RA. T3 or HC. The effect of T3 or HC on lysozyme was not significant. This study shows that RA, T3 and HC influence the morphological phenotype and the secretory function of mucin and lysozyme in cultured human middle ear epithelial cells. This culture system can serve as an in vitro model for study of the regulation of various cellular secretions in human middle ear epithelium.

Value of intracochlear electrically evoked auditory brainstem response after cochlear implantation in patients with narrow internal auditory canal

Cochlear implantation in patients with narrow internal auditory canal (IAC) can result in variable outcomes; however, preoperative evaluations have limitations in accurately predicting outcomes. In this study, we analyzed the outcomes of cochlear implantation in patients with narrow IAC and correlated the intracochlear electrically evoked auditory brainstem response (EABR) findings to postoperative performance to determine the prognostic significance of intracochlear EABR.

Delayed Cochlear Implantation in Adults With Prelingual Severe-to-profound Hearing Loss

Objectives: To evaluate the results of late cochlear implantation in prelingually deaf patients with significant residual hearing loss and to evaluate patient factors relevant to postoperative auditory outcomes in this patient group. Study Design: Analysis of results of cochlear implantation using postoperative speech perception test scores per each condition. Setting: Tertiary referral center. Patients: Thirty-two subjects with severe to profound hearing loss that developed before the age of 4. Interventions: Subjects were implanted at a mean age of 24.8 years (range, 16-44) with Nucleus CI24 (n = 18, 56%), Clarion HiRes 90K (n = 11, 34%), and Medel PULSA (n = 3, 10%) device. Details of etiology, duration of deafness, hearing aid history, hearing thresholds before operation, communication mode, and educational environment were investigated. Speech perception tests were performed preoperatively and 12 months after the operation. Main Outcome Measures: Postoperative speech perception test scores between different options within patient group. Results: The results showed significant improvement in open set speech perception (sentence) scores after the implantation (mean scores from 7.0 to 46.7, p < 0.05). Preoperative hearing of better ear and preoperative speech perception scores correlated with postoperative performances (r = −0.70 and r = 0.46, respectively, p < 0.05). Education and communication mode were also closely related to postoperative performances. In the group with poorer performances, preoperative hearing thresholds were significantly worse than those with better performances, and a larger portion of those patients attended special schools and used sign language. Conclusion: We found that residual auditory capacity in the better ear is an important factor in predicting outcomes after cochlear implantation in patients with prelingual hearing loss.

Wheel-shaped cartilage-perichondrium composite graft for the prevention of retraction pocket development

Conclusion. Our technique can decrease the formation of retraction pockets and improve hearing function. The wheel-shaped cartilage-perichondrium composite graft (Wheel CPCG) can be considered a good material for a drum graft, and it is easy to insert a ventilation tube, in case of initial drum retraction. Objective. The purpose of this study was to introduce the novel surgical technique of a Wheel CPCG with one-stage ossiculoplasty to prevent a retraction pocket and subsequent cholesteatoma after intact canal wall tympanomastoidectomy. Patients and methods. A total of 47 patients were reviewed; 43 cases were selected for audiologic testing. The results of operations were evaluated by comparing preoperative and postoperative hearing results and postoperative drum findings. Results. A retraction pocket was observed in three cases (6.7%). Slight protrusion of partial ossicular replacement prosthesis (PORP) and lateral healing of drum was observed in one case each, and there were two cases of postoperative infection. The number of cases with an air–bone gap (ABG)<20 dB increased from 9 (23%) cases before operation, to 20 cases (51%) after operation. The ABG average statistically decreased from 30.0 dB to 24.0 dB, and the mean air conduction thresholds decreased from a preoperative level of 47.3 dB to a level of 35.7 dB.

Mucin Gene Expression in Cultured Human Middle Ear Epithelial Cells

For the advanced study of the cell and molecular biology of middle ear mucosa, an in vitro cell culture system is required. Although middle ear epithelial cells have been cultured from various species of laboratory animal, there have been no reports concerning a serial subculture system of human middle ear epithelial cells. In this paper, we describe the establishment of a primary culture system of human middle ear epithelial cells using a serum-free conditioned medium and the characterization of these cells by the expression of phenotypic characteristics of epithelial cells and mucin genes. Cultured cells were anchorage-dependent in terms of growth and showed a polygonal cobblestone-like appearance; desmosomes in the cell junction were observed by electron microscopy. In the immunocytochemical study, cytokeratin (epithelial cell marker) was expressed in all cultured cells, but von Willebrand factor (endothelial cell marker) was not. Unexpectedly, vimentin (fibroblast marker) was focally expressed, and a double stain showed the co-expression of both cytokeratin and vimentin in the same cell. The products of reverse transcriptase polymerase chain reaction from cultured cells yielded distinct bands compatible with the expected sizes of the MUC1, MUC2, MUC5AC and MUC5B genes. This culture system will allow us to prepare the cell line and to perform advanced studies of human middle ear mucosal biology.For the advanced study of the cell and molecular biology of middle ear mucosa, an in vitro cell culture system is required. Although middle ear epithelial cells have been cultured from various species of laboratory animal, there have been no reports concerning a serial subculture system of human middle ear epithelial cells. In this paper, we describe the establishment of a primary culture system of human middle ear epithelial cells using a serum-free conditioned medium and the characterization of these cells by the expression of phenotypic characteristics of epithelial cells and mucin genes. Cultured cells were anchorage-dependent in terms of growth and showed a polygonal cobblestone-like appearance: desmosomes in the cell junction were observed by electron microscopy. In the immunocytochemical study, cytokeratin (epithelial cell marker) was expressed in all cultured cells. but von Willebrand factor (endothelial cell marker) was not. Unexpectedly, vimentin (fibroblast marker) was locally expressed, and a double stain showed the co-expression of both cytokeratin and vimentin in the same cell. The products of reverse transcriptase polymerase chain reaction from cultured cells yielded distinct bands compatible with the expected sizes of the MUC1, MUC2, MUC5AC and MUC5B genes. This culture system will allow us to prepare the cell line and to perform advanced studies of human middle ear mucosal biology.

Redistribution of Facial Nerve Motor Neurons after Recovery from Nerve Crushing Injury in the Gerbil

We investigated the redistribution of facial motor neurons after recovery from a crush injury of the facial nerve in the mongolian gerbil, with the retrograde transportation of horseradish peroxidase (HRP) technique. The facial nerve at the vertical segment was crushed unilaterally for 10 s with forceps. After 1 month, movement of the vibrissae and blinking reflex were observed. Three months after nerve injury, we obtained the brainstems to investigate the distribution of the facial nerve motor neurons. On the normal side, motor neurons of the ophthalmic branch of the facial nerve were organized at the dorsomedial and dorsolateral subdivisions of the facial nucleus, and those of the superior buccal branch were distributed at intermediate and ventrolateral subdivisions of the facial nucleus in the brainstem. On the experimental side, instead of somatotopical organization, we found widespread irregular distribution of the motor neurons of both branches in the entire facial nucleus of the brainstem.

Is there a deafness duration limit for cochlear implants in post-lingual deaf adults?

Abstract Conclusion: Patients with post-lingual deafness should not be excluded from cochlear implantation (CI) on the basis of duration of deafness. We found that the prognosis was favorable in patients who developed deafness after adolescence, even in those with extremely long-term deafness. Objectives: CI is an effective treatment for post-lingual deafness. However, it remains unclear whether CI would benefit patients with extremely long-term deafness. We evaluated the auditory performance after CI of patients who had been deaf for more than 30 years. Methods: The study enrolled 81 adults with post-lingual deafness. Speech perception tests were performed preoperatively and 12 months postoperatively, and factors affecting the postoperative auditory performance were investigated. The subjects were divided into groups according to the duration of deafness and the postoperative speech perception scores were compared. Results: A marked improvement in the open-set speech perception scores (mono/disyllabic words and sentences) after implantation was seen in all groups, and no significant difference in the improvement in speech perception scores was observed among the groups. Age at onset of deafness was closely related to the postoperative performance, and patients who had lost their hearing before adolescence performed poorly.

Establishment of primary cell culture from stria vascularis explants. Morphological and functional characterization.

To provide the prerequisite for long-term study of the inner ear related to structural and functional integrity, tissue of stria vascularis with spiral ligament was isolated from Wistar rat cochleas and cultured using the explant-culture technique. The following culture media were used: EMEM with Hepes buffer, hydrocortisone (400 ng/ml), transferrin (5 micrograms/ml). triiodothyronine (10(-9) M), cholera toxin (10(-10) M), insulin (5 micrograms/ml), and epidermal growth factor (10 ng/ml). To characterize the cells growing out from the explant, immunofluorescence with cytokeratin (cytokeratin 18) and ultrastructural examination with SEM and TEM were performed. The marginal cell function was investigated by expression of Na+, K(+)-ATPase antisera against beta 2 subunit of rat Na+, K(+)-ATPase and P-NPPase. We were able to maintain the cultured cells for 3 weeks or more. Monolayered marginal cells were observed beyond 14 days in vitro and the expression of cytokeratin 18 was especially enhanced. The cultured marginal cells were almost identical to in vivo cells both as regards ultrastructural features and Na+, K(+)-ATPase activity. The present results suggest that the primary explant culture technique is a reliable in vitro model of strial marginal cells. However, establishment of the cell line is needed for long-term study.