Surgical and Audiologic Comparison Between Sophono and Bone-Anchored Hearing Aids Implantation

OBJECTIVES: Bone-anchored hearing aids (BAHA) occasionally cause soft tissue problems due to abutment. Because Sophono does not have abutment penetrating skin, it is thought that Sophono has no soft tissue problem relating to abutment. On the other hand, transcutaneous device's output is reported to be 10 to 15 dB lower than percutaneous device. Therefore, in this study, Sophono and BAHA were compared to each other from surgical and audiological points of view. METHODS: We retrospectively reviewed the medical records of 9 Sophono patients and 10 BAHA patients. In BAHA cases, single vertical incision without skin thinning technique was done. We compared Sophono to BAHA by operation time, wound healing time, postoperative complications, postoperative hearing gain after switch on, and postoperative air-bone gap. RESULTS: The mean operation time was 60 minutes for Sophono and 25 minutes for BAHA. The wound healing time was 14 days for Sophono and 28 days for BAHA. No major intraoperative complication was observed. Skin problem was not observed in the 2 devices for the follow-up period. Postoperative hearing gain of bilateral aural atresia patients was 39.4 dB for BAHA (n=4) and 25.5 dB for Sophono (n=5). However, the difference was not statistically significant. In all patients included in this study, the difference of air-bone gap between two groups was 16.6 dB at 0.5 kHz and 18.2 dB at 4 kHz. BAHA was statistically significantly better than Sophono. CONCLUSION: Considering the audiologic outcome, BAHA users were thought to have more audiologic benefit than Sophono users. However, Sophono had advantages over BAHA with abutment in cosmetic outcome. Sophono needed no daily skin maintenance and soft tissue complication due to abutment would not happen in Sophono. Therefore, a full explanation about each device is necessary before deciding implantation.

Carrier frequency of SLC26A4 mutations causing inherited deafness in the Korean population

PURPOSE: The mutation of the SLC26A4 gene is the second most common cause of congenital hearing loss after GJB2 mutations. It has been identified as a major cause of autosomal recessive nonsyndromic hearing loss associated with enlarged vestibular aqueduct and Pendred syndrome. Although most studies of SLC26A4 mutations have dealt with hearing-impaired patients, there are a few reports on the frequency of these mutations in the general population. The purpose of this study was to evaluate the prevalence of SLC26A4 mutations that cause inherited deafness in the general Korean population. MATERIALS AND METHODS: We obtained blood samples from 144 Korean individuals with normal hearing. The samples were subjected to polymerase chain reaction to amplify the entire coding region of the SLC26A4 gene, followed by direct DNA sequencing. RESULTS: Sequencing analysis of this gene identified 5 different variants (c.147C>G, c.225G>C, c.1723A>G, c.2168A>G, and c.2283A>G). The pathogenic mutation c.2168A>G (p.H723R) was identified in 1.39% (2/144) of the subjects with normal hearing. CONCLUSION: These data provide information about carrier frequency for SLC26A4 mutation-associated hearing loss and have important implications for genetic diagnostic testing for inherited deafness in the Korean population.

Single Vertical Incision Technique without Skin Thinning for the Bone Anchored Hearing Aid Surgery / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: After the bone anchored hearing aid (BAHA) surgery, soft tissue problems have frequently been reported. To solve this problem, a surgical procedure that routinely involves so-called skin thinning using BAHA dermatome has been utilized. But, this procedure includes many peri-implant complications and cosmetic trouble. Recently, a single vertical incision technique that does not involve skin thinning has been reported with favorable results. In this study, we evaluated the benefits of performing this procedure without skin thinning compared with the dermatome technique. SUBJECTS AND METHOD: We evaluated 10 patients who were operated on without skin thinning using longer (8.5 mm) abutments (the test group) and 5 patients with the routine skin thinning and 5.5-mm abutments (the control group). A mean follow-up time was 11.3 months, the mean age was 34.2 years in the test group, the mean follow-up time was 54.5 months and a mean age is 24.5 years in the control group. RESULTS: The mean time required for surgery was 25 minutes and 55 minutes for the test and control groups, respectively. The wound healing time was 28 days and 56 days for the test and control groups, respectively. Fixture extrusion, skin infection and skin overgrowth were not observed in the test group but fixture extrusion case, two skin infection cases and two skin overgrowth cases were observed in the control group. Two cases of abutment loosening were observed in the test group. CONCLUSION: The single vertical incision technique without skin thinning has many benefits when compared with the BAHA dermatome. With this technique, infection and skin overgrowth could be reduced, and a more rapid procedure and a more short healing time could also be possible. Moreover, the aesthetic outcome was far better when no skin thinning was involved.

Genetic Screening of GJB2 and SLC26A4 in Korean Cochlear Implantees: Experience of Soree Ear Clinic

OBJECTIVES: Genetic hearing loss is highly heterogeneous and more than 100 genes are predicted to cause this disorder in humans. In spite of this large genetic heterogeneity, mutations in SLC26A4 and GJB2 genes are primarily responsible for the major etiologies of genetic hearing loss among Koreans. The purpose of this study is to investigate the genetic cause of deafness in Korean cochlear implantees by performing a genetic screening of the SLC26A4 and GJB2 genes. METHODS: The study cohort included 421 unrelated Korean patients with sensorineural hearing loss (SNHL) and who had received cochlear implants (CI) at Soree Ear Clinic from July 2002 to December 2010. Among 421 CI patients, we studied 230 cases who had received the genetic screening for SLC26A4 or GJB2 genes. Written informed consent was obtained from all participants. All patients had severe to profound, bilateral hearing loss. For 56 patients who showed enlarged vestibular aqueduct on their computed tomography (CT) scan, we analyzed SLC26A4. For 174 CT negative patients, GJB2 gene was sequenced. RESULTS: For the 56 SLC26A4 patients, 32 (57.1%) had two pathogenic recessive mutations in SLC26A4. A single recessive SLC26A4 mutation was identified in 14 patients (25%). H723R and IVS7-2A>G were the most commonly found mutations, accounting for 60.3% (47/78) and 30.8% (24/78) of the mutated alleles, respectively. For the 174 GJB2 patients, 20 patients (11.5%) had two pathogenic recessive mutations in GJB2. 235delC was the most common mutation, accounting for 43.0% (31/72) of mutant alleles. CONCLUSION: The two major genes, SLC26A4 and GJB2, contribute major causes of deafness in CI patients. Continuous studies are needed to identify new genes that can cause hearing loss to Korean CI patients.

Retraction: Signal Transduction System of Experimentally Induced Cholesteatoma in the Mongolian Gerbil / 대한이비인후과학회지

No abstract available.

Retraction: Mechanism of Apoptotic Cell Death in Cholesteatoma Epithelium / 대한이비인후과학회지

No abstract available.

Retraction: Molecular Genetic Analysis of Connexin 26 in Korean Congenital Hearing Loss / 대한이비인후과학회지

No abstract available.

Clinical Follow-up of Hearing-Impaired Infants Detected by Newborn Hearing Screening / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: When screened using cord blood, congenital hearing loss are detected more frequently than other congenital metabolic diseases such as phenylketonuria or congenital hypothyroidism. Newborn hearing screening is important because the early identification and intervention of neonatal hearing loss is beneficial for the language development. We aimed to analyze clinical characteristics including associated diseases and present hearing state, and the effects of speech rehabilitation in the hearing-impaired infants detected by newborn hearing screening program of Ajou University Hospital. SUBJECTS AND METHOD: Seventy nine hundred twelve neonates (6915 well babies and 997 NICU babies) were screened by transient evoked otoacoustic emission (TEOAE) and auditory brainstem response (ABR). Medical records of infants with bilateral hearing loss of more than 60 dB were evaluated, and they were further studied with temporal bone CT scan and follow-up hearing tests using ABR. The exon2 of the connexin26 gene was sequenced to detect the mutation. RESULTS: Fourteen of 7912 infants initially had bilateral hearing loss of more than 60 dB. Associated diseases were prematurity, hyperbilirubinemia, sepsis, low birth weight, chromosomal anomaly, cleft palate, congenital nevus, and congenital aural atresia. Three of 14 infants were revealed to have normal hearing after follow-up hearing test, which were associated with cleft palate, hyperbilirubinemia or prematurity. One of them had 235delC mutation of the connexin26, and the temporal bone CT scan demonstrated the finding of enlarged vestibular aqueduct syndrome (EVAS) in one infant. Two infants participated in the connected speech rehabilitation program and showed significant development of language. CONCLUSION: Follow-up hearing tests are important in case of failures of newborn hearing screening test. The establishment of auditory and speech rehabilitation program connected with newborn hearing screening is essential in treating hearing-impaired neonates.

Treatment Effects of Glutamate Antagonist for Tinnitus / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Tinnitus is one of the most widespread disorders of the auditory system, affecting approximately 17% of the general population, with the frequency increasing to about 33% in the elderly. However, little is known about the underlying physiological mechanism that causes tinnitus and there is no definite treatment. Recently, several studies have showed that subjective tinnitus is mostly generated at the synapse between inner hair cells and their afferent nerves and in addition, some have showed that glutamate is likely to act as the neurotransmitter. The aim of this study has been to evaluate the effective use of caroverine hydrochloride and memantine hydrochloride for tinnitus treatment and to determine their appropriate indication of glutamate antagonist therapy. MATERIALS AND METHOD: From May 1998 through June 2000, 188 patients with subjective tinnitus were treated with caroverine hydrochloride (Spamon(R)). Of the patients, 153 were followed, and 20 of these patients who did not respond to caroverine hydrochloride were treated additionally with memantine hydrochloride (Akatinol(R)). Audiological evaluations were performed in all of the patients. Pre and post-treatment status was analyzed by handicap inventories. RESULTS: Subjective tinnitus was improved in 55 (35.9%) of 153 patients who were treated with caroverine hydrochloride and 11 (55.0%) of 20 patients with memantine hydrochloride. The response group had tendency of shorter duration history of tinnitus than the non-response group. There was no difference between the response group and the non-response group in age, sex, site, and tinnitus characteristics. CONCLUSION: We suggest that glutamate antagonists such as caroverine hydrochloride and memantine hydrochloride can be used as an alternative modality for treatment of subjective tinnitus.

Results and Cost-Effectiveness of Newborn Hearing Screening Program in Ajou University Hospital / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: It is estimated that more than 2 in every 1,000 neonates suffers from hearing loss. Early detection with appropriate rehabilitation of congenital hearing loss can reduce the adverse developmental consequences such as language delays, and behavior and attention deficits. The purpose of this study is to evaluate our newborn hearing screening program using the combined transient evoked otoacoustic emission (TEOAE) and auditory brainstem response (ABR), and to estimate the cost-effectiveness of our program. MATERIALS AND METHOD: 6,634 infants (5,918 well babies and 716 NICU babies) underwent the newborn hearing screening program at Ajou University Hospital for 4 years. Initially well babies were screened with TEOAEs, and those failing the TEOAEs were tested with the rescreening program. Neonates failing the TEOAE rescreening and the NICU babies were examined with ABR. The cost included personnel, fringe benefits, supplies, equipment and overhead. RESULTS: 660 (11%) out of 5,918 well babies failed the initial TEOAE screening and 27 (0.46%) babies failed the TEOAE rescreening. Eleven babies (0.16%), 3 of the well babies and 8 of the NICU babies, were confirmed to have hearing loss of more than 60 dB. We detected four deaf babies out of these eleven. From the four deaf babies, we confirmed a connexin 26-related deafness and an enlarged vestibular aqueduct syndrome. It cost $6 to screen one infant and $3,700 to detect one infant with hearing loss. CONCLUSION: We could detect 11 babies (0.16%) with hearing loss out of 6,634 neonates during the 4 years. Considering the benefits of early identification and rehabilitation of congenital hearing loss, the cost for the newborn hearing screen program is affordable. The newborn hearing screen should be extended as a national health program.

A Functional Study of Gap Junction in GJB2 Mutations Associated with Hereditary Hearing Loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: GJB2 (Connexin 26), the gene of the gap-junction proteins, was found to be the main causative gene of autosomal recessive nonsyndromic hearing loss (DFNB1). Whereas 35delG was known as the major type mutation in the western countries, 235delC was reported as the specific form of mutation in Asian population. The objective of this study is to identify how two mutations (235 delC, E114G) found in the Korean population affect the function of GJB2 using the molecular biology techniques. MATERIALS AND METHODS: 235delC and E114G types of mutations were cloned in the pcDNA3 vector. HeLa cells were transfected with these cloned vectors by the liposome complex method. 1) The expression and subcellular localization of Cx26 were determined using antibodies against amino acid sequences in the intracellular loop (IL) and N-terminal (NT) portions of Cx26. 2) To analyze functions of the GJB2, we examined the lucifer yellow dye transfer between cells with scrape-loaded technique. We used the wild-type (WT) Cx26 of normal hearing as a positive control, and mock cells as a negative control. RESULTS: The immunocytochemical analysis showed that cells transfected with E114G and WT gave characteristic punctuated patterns of reaction in the cell membrane with both antibodies. However, 235delC cells were not stained with the anti-IL antibody but only with the anti-NT antibody slightly around the nucleus regions. In the functional study of GJB2, transfer of lucifer yellow dye into contiguous cells was detected in E114G but not in 235delC. CONCLUSION: The 235delC type of mutation showed loss of their targeting activity on the cell membrane. As a result, the function of gap junction channels were severely deteriorated. With the E114G type mutation, we didn't find any difference when compared with the WT transfected cells. Above data indicate that types of GJB2 mutation are closely related to the status of hearing loss due to altered function of gap junction protein.

The Significance of T2-Weighted, Fast-Spin Echo Magnetic Resonance Imaging Scan in a Screening Test for Patients with Acoustic Tumor / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES:Although auditory brainstem response(ABR) has been the screening test of choice, recent studies showed that ABR had only a 63% sensitivity and 64% specificity in detecting small acoustic tumor when compared with the magnetic resonance imaging(MRI) scan. Full MRI scans with gadolinium enhancement are highly accurate at detecting these lesions, but these are time consuming and expensive. The purpose of this study is to evaluate the effectiveness of T2-weighted, fast-spin echo(FSE) MRI scan as a screening test for acoustic tumor compared with full MRI scans with gadolinium enhancement. PATIENTS AND METHODS : From January 1995 through March 1999, 293 patients visiting to Department of otolaryngology underwent full MRI scans with gadolinium enhancement including T2-weighted FSE MRI to rule out the acoustic tumor. Pure tone audiogram was routinely performed in all the patients. One hundred fifty four of these patients received speech audiogram. Decreased speech discrimination score below 60% was considered abnormal. ABR was ordered to 65 patients. Interaural latency difference for wave V greater han 0.2 msec was considered abnormal. RESULTS: Eleven of 293 cases were detected as acoustic tumor on T2-weighted FSE MRI scan and gadolinium-enhanced MRI scan. The tumors less than 1.5 cm in diameter were 7 cases, and 3 cases of normal ABR was all less than 1 cm in diameter. T2-weighted FSE MRI scan had 100% sensitivity and 99.6% specificity, while ABR showed relatively low sensitivity(72.7%) and specificity(33.3%). CONCLUSION: T2-weighted FSE MRI scan is so sensitive to acoustic tumor that is comparable to full MRI scans with gadolinium enhancement. And it has rapid performance time and low cost. However, ABR has low sensitivity for acoustic tumor, especially for small tumor less than 1 cm in diameter. So, T2-weighted FSE MRI scan is considered as a cost-effective screening test for early detection of acoustic tumor.

Molecular Genetic Analysis of Connexin 26 in Korean Congenital Hearing Loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Congenital deafness is a relatively common disorder and its' incidence is as high as 1 per every 1, 000 newborn infants. In developed countries, genetic hearing loss accounts for 50% of all hearing losses. A least 20 autosomal recessive loci had been identified, and in 1997, Connexin 26, one of the gap-junction proteins, was found to be the main mutant gene of non-syndromic congenital sensorineural hearing loss. The objective of this study is the investigation of the clinical features and characteristics of connexin 26 mutation in congenital deaf patients in Korea. MATERIALS AND METHODS: Fifty-one patients who have visited the out-patient department of Ajou University Hospital and 125 patients attending two special schools for deafness were physically examined. Family history of each patient was also examined. One hundred normal hearing infants who were audiologically approved were selected as a control group. With their blood samples, we performed DNA extraction and sequenced PCR products. RESULTS: Among 176 patients, 53 patients had family history of hearing impairment, and 16 patients actually showed syndromic features. We sequenced Connexin 26 in 121 patients who have congenital non-syndromic sensorineural hearing loss. Two heterozygotes of 35delG, three heterozygotes, four homozygotes of 235delC, 35 heterozygotes, and four homozygotes of E114G were observed. CONCLUSION: Family history of deafness was relatively common among the patients and therefore it was an important factor in deciding that hearing loss was due to genetic origin. Syndromic hearing loss occupies a relatively minor portion of congenital deafness. With regard to Connexin 26 mutation, 35delG is reported as the major gene mutation in the western countries, but in our study, only 2 patients had this type of mutation. Therefore, 235 delC. and E114G can be considered as race specific gene mutations, even though further studies are need.

Measurement of Speech Reception Threshold by Picture Identification in Young Children / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Young children response more readily to speech than to pure tone stimuli. Although there are several reports on modification of speech Reception Threshold Testing by picture identification in the States, none has been reported in Korea. MATERIALS AND METHODS: In this study, we investigated the testing of SRT-PI in 102 young children of normal development between 24 and 36 months. All subjects were tested not only with SRT-PI but also with play audiometry in the same condition. RESULTS: Overall success rate of SRT-PI was 80.3% while only 3.9% of subjects were successful in play audiometry. The success rate of SRT-PI was significantly higher in the 29-36 months group than in the 24-28 months group. Test time and threshold did not show significant differences between in sex and age of subjects with regard to SRT-PI. CONCLUSION: SRT-PI is a simple, efficient and very useful test battery for audiologic evaluation in young children.

TEOAE as a Newborn Hearing Screening / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Hearing impairment is a common congenital disability of the newborn, which has an incidence of 1.5 to 3 per 1,000 infants each year. The identification of this problem is difficult and many of these children are not identified until 2-3 years of age if not screened at birth. The purpose of this study is to establish a common screening method adjusted to our country and to emphasize the importance of early diagnosis of neonatal hearing loss. MATERIALS AND METHODS: TEOAE were performed in 1,459 infants from March to December, 1998 at Ajou university hospital. The tests were performed daily until discharge if the infant had failed the first test, and were followed at the outpatient clinic. Hearing loss was confirmed by ABR. RESULTS: The average test time of TEOAE was 102.6 seconds. Test time after 24 hours of birth was shorter than before 24 hours, and was shorter in female compared to male infants. Pass rate after 24 hours was higher than before 24 hours and 86% of tested infants passed during admission. Thirty-one out of 213 infants failed to follow-up at the outpatient clinic. Two were diagnosed with unilateral hearing loss on ABR. CONCLUSION: TEOAE is a simple and useful screening method for the identification of hearing loss in infants.

Decision Analysis in Diagnosis of Small Acoustic Tumors / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: With great development that took place in the last 10 years in the imaging techniques such as MRI with gadolinium, small acoustic tumors can be detected before significant symptoms have developed. However, suspicion of acoustic neuroma is not easy at its earlier stage due to the lack of its characteristic symptoms. The detection rate of acoustic neuroma using traditional audiologic methods such as ABR and pure tone audiogram with speech discrimination score is relatively low contrary to expectation. Therefore, there is a need to develop other methods of diagnosis at an earlier stage. The aim of this study was to review symptomatology, diagnostic approach and the management of acoustic neuroma and to make a decision analysis tree of the diagnostic work-up. MATERIALS AND METHODS:From June 1994 through May 1998, eight patients with a small acoustic neuroma were treated at Ajou University Hospital. We analysed these 8 patients by age, sex, chief complaint, size of tumor, preoperative and postoperative audiologic studies, caloric test, treatment modalities and preoperative and postoperative imaging study. RESULTS: Acoustic neuroma had variable symptoms, with the most common initial symptom of our cases being sudden hearing loss. The sensitivity of ABR was relatively lower than we thought. Two out of three in the observation group showed an abrupt deterioration of hearing. CONCLUSION: When acoustic neuroma is suspected in patients with unilateral hearing loss, tinnitus and dizziness are very important symptoms to consider. We developed a decision analysis tree for diagnosis of small acoustic neuroma, which should be treated with earlier intervention of MRI.

Expression of PCNA in Experimental Cholesteatoma by Implanting Autologous Free Skin Graft in Mongolian Gerbil Middle Ear Cavity / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Cholesteatoma in the middle ear is characterized by the presence of a keratinizing epithelium which is believed to have hyperproliferative properties. Among the various approaches for evaluating proliferative activity, proliferating cell nuclear antigen (PCNA) has been recently induced as an antigenic marker of cellular proliferation. In this study, we investigated the hyperproliferative characteristic of implanted skin in Mongolian gerbil middle ear cavity by comparing its mitotic activity with that of the retroauricular skin. A secondary purpose was to provide the morphological basis for future animal studies concerning cholesteatoma pathogenesis. MATERIALS AND METHODS: Using immunohistochemical technique with anti-monoclonal antibody, we investigated PCNA expressions of the implanted free skin and normal retroauricular skin of Mongolian gerbils. RESULTS: Experimental cholesteatoma induced by implanting free skin graft showed an average PCNA labeling index of 0.47+/-0.07 and normal retroauricular skin revealed 0.14+/-0.05. The labeling index of experimental cholesteatoma was 3.47 times higher than that of normal retroauricular skin. CONCLUSION: The epithelium of experimental cholesteatoma induced by implanting free skin graft in gerbil middle ear cavity proliferates at a higher rate than its normal retroauricular skin, suggesting that this animal model can be used for future study of epithelial proliferation of cholesteatoma.

Immunohistochemical Study of Thrombomodulin in Experimental Cholesteatoma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The hyperproliferative character of human cholesteatoma epithelium was confirmed through various hyperproliferation associated antibody expressions. Among the various approaches for evaluating proliferative activity, thrombomodulin (TM) is a cell surface glycoprotein which forms a high affinity non-covalent complex with thrombin and is a differentiation marker for spinous layer keratinocytes. Several animal models have been introduced to study cholesteatoma pathogenesis, among which canal ligation model using Mongolian gerbils is of much interest, because it can potentially provide information on cell differentiation and proliferation of cholesteatoma. In this study, we investigated the hyperproliferative characteristics of canal ligation cholesteatoma by comparing deep meatal skin and retroauricular skin. Another purpose of this study was to provide the morphological basis for further animal studies concerning cholesteatoma pathogenesis. MATERIALS AND METHOD: Using immunohistochemical technique with anti-monoclonal antibody, we investigated TM expression in the canal ligation cholesteatoma, deep meatal skin and retroauricular skin of Mongolian gerbil. RESULTS: Experimental cholesteatoma induced by canal ligation and deep meatal skin showed TM expression especially in the suprabasal layers. TM expression of experimental cholesteatoma is much more intense than that of deep meatal skin. CONCLUSION: Experimental cholesteatoma revealed an altered differentiation in suprabasal layer, suggesting that this animal model can be used for further study in the epithelial differentiation and proliferation of cholesteatoma.

Signal Transduction System of Experimentally Induced Cholesteatoma in the Mongolian Gerbil / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Hyperproliferative character of the cholesteatoma in the middle ear seems to be related to epithelial cell proliferation and differentiation. The proliferation of cells, their differentiation and organization in specialized tissues and the expression of their differentiated properties are under control of a large number of regulatory processes and complex interactions called signal transduction. PLC-gamma1 is a substrate of protein kinase located in EGFR, PDGFR-alpha and -beta and signal transduction through PLC-gamma1 participates in the regulation of cell growth and differentiation. This study was undertaken to investigate the distribution of PLC-gamma1, EGFR and PDGFR in experimentally induced cholesteatoma, deep meatal skin and retroauricular skin of Mongolian gerbil. MATERIALS AND METHODS: Using Western blotting and immunohistochemical techniques, we investigated the reaction patterns of antibody to PLC-gamma1, EGFR, PDGFR-alpha and PDGFR-beta as a proliferation and differentiation marker in the experimentally induced cholesteatoma matrices of Mongolian gerbil. For the control, same study was performed with deep meatal skin and retrosuricular skin. RESULTS: By Western blotting, considerably higher levels of PLC-gamma1, EGFR protein were detectable in cholesteatoma compared with control, however, PDGFR-alpha and -beta were not detected in cholesteatoma The immunostaining intensity of PLC-gamma1 and EGFR at suprabasal cell layer and basal cell layer were intense in cholesteatoma than in control. PDGFR-alpha and -beta were not detected in both cholestatoma and control. CONCLUSION: Over-expression of PLC-gamma1 and EGFR in induced cholesteatomas may contribute abnormal proliferation and differentiation of their epithelial cell. Authors suggest that induced cholesteatoma in Mongolian gerbils can be a good model of signal transduction study for cholesteatoma.

Secretory Differentiation of Serially Passaged Normal Human Middle Ear Epithelial(NHMEE) Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to subculture normal human middle ear epithelial (NHMEE) cells, investigate whether the subcultured NHMEE cells could have ability to differentiate into secretory cells, and establish a method to get cultured NHMEE cells for further study of human middle ear epithelial differentiation and secretion. MATERIALS AND METHOD: Freshly isolated epithelial cells from healthy middle ear mucosa were subcultured repeatedly after enzymatic disaggregation in serum-free medium on plastic tissue culture dishes. The subcultured cells were counted after every passage and tested for secretory differentiation in air-liquid interface (ALI) cultures. The apical secretion of cultured NHMEE cells were characterized by immunoblotting and Western blotting. RESULTS: Attachment rate of subcultured NHMEE cells was over 70% through every passage. Cells proliferated by 22 fold from passage-1 to passage-2 (P-2), but passage-4 cells did not proliferate. P-2 NHMEE cells in ALI cultures was stained with mucin antibody (H6C5) but not b-tubulin antibody. Cultured NHMEE cells secreted mucin and lysozyme. CONCLUSION: P-2 NHMEE cell cultures retained many important features of normal epithelium and were suitable for conducting many studies of human middle ear epithelial cell biology including cell differentiation and secretion.