Keehyun Park

Nitric oxide mediates TNF-α-induced apoptosis in the auditory cell line.

Tumor necrosis factor‐alpha (TNF‐α) is released in a variety of pathological states in the inner ear. Inducible nitric oxide synthase (iNOS) can be induced by cytokines and other inflammatory factors, and is generally thought to be associated with inflammation and other pathological processes in the cochlea. The purpose of the present study was to reveal that TNF‐α could induce apoptosis in the auditory cell line and to investigate the role of nitric oxide (NO) in TNF‐α–induced auditory cell death.

Conductive deafness with normal eardrum: absence of the long process of the incus.

Conclusions. The most likely cause of lesions with an absence of the long process of the incus was congenital origin because many cases were associated with the stapedial anomaly. However, the possibility of a potential inflammation of this lesion could not be completely excluded, especially in cases with only an absence of the long process of the incus. Objective. To clarify whether the absence of the long process of the incus is caused by congenital anomaly or a potential inflammation. Subjects and methods. A total of 21 patients (5 bilateral cases, 16 unilateral cases) with absence of the long process of the incus were reviewed. Operative and histopathological findings of the removed incus were analyzed. Results. The 21 cases with absence of the long process of the incus were classified into 6 types. Thirteen cases showed the absence of the long process associated with the stapedial anomaly, which were all unilateral. Eight cases showed no association with the stapedial anomaly, among which five cases were bilateral. Three of eight cases not associated with the stapedial anomaly showed evidence of resorption in the incus body such as fibrosis and Haversian canal widening.

Optimum oxygen concentration for the optoelectronic properties of IR sensitive VOx thin films

Abstract VO x films were fabricated on thermally grown SiO 2 layers by reactive r.f. sputtering at room temperature. The working pressure was 5 mTorr, adjusted by changing Ar and O 2 flow from 1:1 to 10:1. Post annealing was performed at the temperatures of 200°C, 300°C, 400°C, 450°C, and 500°C. Electrical resistivities of VO x films were measured at various temperatures from 25°C to 80°C and the temperature coefficient of resistance (TCR) was calculated for each film. The resistivity decreases with the increase of the annealing temperature and shows two steps of critical drops at 300°C and 450°C, respectively. This is attributed to the phase transitions of the as-deposited VO x as characterized by X-ray diffraction (XRD). Considering both the TCR and resistivities, it is concluded that the optimum oxygen concentration, x in the VO x films approaches to 2.25 (V 4 O 9 ).

Diagnostic efficiency of the cochlear hydrops analysis masking procedure in Ménière's disease.

Objective To determine whether cochlear hydrops analysis masking procedure (CHAMP) has diagnostic value in patients with definite Ménière’s disease (MD) comparing the diagnostic validity index of CHAMP with those of electrocochleography (ECoG). Study Design A prospective study. Setting Tertiary referral center. Patients One hundred eight patients were classified into 3 groups: the “definite MD” group (MD group, n = 47); the “non-MD” group (n = 41) of other vestibular diseases including vestibular neuritis, and benign paroxysmal positional vertigo; and the control group (n = 20), which included patients without dizziness. Interventions CHAMP and extratympanic ECoG were performed in all patients. Main Outcome Measure Sensitivity, specificity, and definitions of abnormal values were less than 0.3 ms in latency delay (0.5 kHz high pass noise [HPN]–click alone) and less than 0.95 in compound amplitude ratio (click alone–0.5 kHz HPN/click alone) in CHAMP and 0.4 for the summating potential/action potential ratio in ECoG. Results The mean latency delay and amplitude ratio of CHAMP in the MD group significantly differed from these values for other groups, whereas the mean summating potential/action potential ratio of ECoG did not. In ECoG, sensitivity was as low as 21%, specificity was 97%, and diagnostic accuracy was 62%. Sensitivity, specificity, and diagnostic accuracy of CHAMP were 64%, 98%, and 80%, respectively, in latency delay and 91%, 83%, and 88%, respectively, in amplitude ratio. The sensitivity and diagnostic accuracy of CHAMP were significantly higher than the corresponding values for ECoG. Conclusion CHAMP is more valuable in detection of definite MD than extratympanic ECoG.

Cochlear implantation in a case with Waardenburg syndrome

(2004). Cochlear implantation in a case with Waardenburg syndrome. Cochlear Implants International: Vol. 5, No. sup1, pp. 212-214.

The oncoprotein, gankyrin, is up-regulated in middle ear cholesteatoma

Abstract Conclusion: Gankyrin seems to be a better biomarker for cholesteatoma compared with Ki-67. Objective: Gankyrin is an oncoprotein, and occurs in cancers but not in benign diseases. The goal of this study was to compare expression of gankyrin, p53, and a proliferation marker (Ki-67) in cholesteatoma and retroauricular skin (RAS), and to evaluate their significance as clinical parameters. Methods: The levels of expression of gankyrin, Ki-67, and p53 in 10 cholesteatoma and 10 paired samples of normal RAS were evaluated by immunohistochemical staining and Western blot. The results were compared with clinical profiles to investigate a correlation. Results: The expression of gankyrin, Ki-67, and p53 proteins was observed in both basal and suprabasal layers of cholesteatoma. The intensity of gankyrin expression was ‘positive’ in two cases (20%) and ‘strongly positive’ in eight cases (80%); p53 expression in the suprabasal layer was ‘positive’ in 70% of cases; and the Ki-67 staining was ‘focal’ in 80% of cases. In RAS, these proteins were expressed dominantly in the basal layer. Western blot analysis showed that the gankyrin band was more intense in cholesteatoma than in RAS for three of four cases (p < 0.05). However, there was no significant difference in the expression of gankyrin, Ki-67, and p53 according to clinical variables.

The significance of 180-degree head rotation in supine roll test for horizontal canal benign paroxysmal positional vertigo.

Objective The relatively low success rate of the treatment maneuver for horizontal semicircular canal (HSC) benign paroxysmal positional vertigo (BPPV) may be caused by the difficulty determining the affected side. We developed a 180-degree supine roll test (SRT) by modifying the 90-degree SRT to increase diagnostic accuracy and evaluated its significance. Study Design A prospective study. Setting Tertiary referral center. Patients A total of 122 patients with HSC-BPPV performed both the 90- and 180-degree SRTs. Interventions The affected side was determined by the 90- and 180-degree SRTs. The bow and lean (BL) test was also performed in cases with ambiguous or opposite results on both SRTs. Main Outcome Measure A comparison of the difference in slow phase velocity (SPV) of nystagmus among the 90- and 180-degree SRTs and BL test. Results The maximum SPV of nystagmus during the 180-degree SRT was significantly greater than that during the 90-degree SRT. The SPV difference was less in the 180-degree SRT than that in the 90-degree SRT. Although the 180-degree SRT showed fewer meaningful results (n = 65) than the 90-degree SRT (n = 71), the affected side was determined by the 180-degree SRT in 15 cases with ambiguous results on the 90-degree SRT. Among 10 cases showing opposite results, 7 were identified by the BL test. Five (71.4%) of 7 cases had consistent affected sides with the 180-degree SRT. Conclusion The 180-degree SRT can be an additional method when it is difficult to determine the affected side from the 90-degree SRT.

Response to: “Possible Errors in Hearing Recovery Results” from Kai-Min Fang

In response to Dr Fang’s letter regarding our article titled “Efficacy of 3 Different Steroid Treatments for Sudden Sensorineural Hearing Loss: A Prospective, Randomized Trial,” 1 we thank Dr Fang for thorough comments. We regret and admit our errors in the description about hearing gain results in Figure 4 despite several revisions of our article before publication. We checked our original data again and reanalyzed it with the correct one. As the average hearing gain in group I is corrected to 18.7 ± 19.1 dB, the total average hearing gain should be 17.6 ± 20.6. Despite the amendment, the differences in hearing gains among the 3 groups using the Kruskal-Wallis test did not show statistical significance ( P > .05). In our article, we assessed treatment outcome in aspects of hearing gain (dB) and recovery rate (%) according to “Clinical Practice Guideline: Sudden Hearing Loss” from the American Academy of Otolaryngology—Head and Neck Surgery in 2012. Therefore, the conclusion corresponds to our original article even after the correction of hearing gain result in group I. We do admit that there were some limitations in small sample size and study design as we previously mentioned in discussion. 1

The clinical significance of AAO-HNS guidelines for meniere’s diseases

Background and Objectives : The guidelines for Menieres disease recommended from the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) in 1995, provided a basis for reporting results of the treatment used in Menieres disease. However, these guidelines are sometimes not all inclusive and appropriate for management and reporting for some patients clinically considered having Menieres disease. The objectives of this study is to review and analyze the symptoms, vertiginous episodes, audiometry, vestibular function test and results of the treatment in Menieres disease and to evaluate the significance of AAO-HNS guidelines. Materials and Method : This study consisted of the patients with Meniere symptoms who visited the Dizziness Clinic of Ajou University Hospital between 1994 and 2001 were included in this study. The characteristics of dizziness (duration, frequency, and episodes), pure tone audiometry, vestibular function tests, and treatment results were carefully analyzed according to AAO-HNS guidelines. Results :Of 550 patients with Meniere symptoms, 198 patients were in the criteria for Menieres disease. They were classified to 75 (37.9%) of the “definite”, 120 (60.6%) of the “possible”, and only 3 (1.5%) of the “probable”. In the “definite” group, the pure tone average (PTA) was 54.3 dB and canal paresis (CP) was showed in 33 patients (44%) with a mean CP of 53.6%, and the peak and descending types of the pure tone audiogram were dominant (62%). In the “possible” group, the PTA was 19.4dB and CP was found in 30 patients (25%) with mean CP of 50.1%. Conclusion : Even though AAO-HNS guidelines for Menieres disease are helpful for communication between doctors, they should be considered to have limitations for the diagnosis and treatment in clinical practices.