Sung-Il Nam

Interleukin-1β up-regulates inducible nitric oxide by way of phosphoinositide 3-kinase-dependent in a cochlear cell model

Objective: To investigate the effect of interleukin (IL)‐1β on inducible nitric oxide (iNOS) expression in cochlea and the molecular and signaling mechanisms involved.

An unusual case of neuro-Behçet’s disease presenting with reversible basilar artery occlusion

Neuro-vasculo-Behçet’s disease is considered a venous vessel disease generally in the form of cerebral venous thrombosis. Arterial involvement has been rarely reported. We present a patient with neuro-Behçet’s disease who developed reversible basilar artery occlusion. To the best of our knowledge, this is the first case of neuro-Behçet’s disease presenting with reversible basilar artery occlusion. Behçet’s disease should be considered in the differential diagnosis of basilar artery occlusion.

Objective Tinnitus Concomitant with Eye Blinking: A Case Report

Tinnitus is a common auditory phenomenon associated with many otological diseases, and is usually subjective. Objective tinnitus can be generated by para-auditory structures, usually derived from vascular or myogenic sources, or the eustachian tube. We present a rare case of intermittent unilateral tinnitus associated with eye blinking. Otoendoscopic examination showed that the external auditory canals and tympanic membranes were normal; however, rhythmic movements of both tympanic membranes, concomitant with the tinnitus, were evident whenever the patient blinked. The tympanometry and stapedial reflexes measured via impedance audiometry exhibited saw-tooth patterns; movement of the tympanic membrane was associated with eyelid blinking. The patient was managed conservatively, with reassurance and medication, and the condition became well-controlled. Here, we present this educational case and review the literature.

Dexamethasone Inhibits Interleukin-1β-Induced Matrix Metalloproteinase-9 Expression in Cochlear Cells

Objectives To investigate the effect of interleukin (IL)-1β on matrix metalloproteinase (MMP)-9 expression in cochlea and regulation of IL-1β-mediated MMP-9 expression by dexamethasone and the molecular and signaling mechanisms involved. Methods House ear institute-organ of Corti 1 (HEI-OC1) cells were used and exposed to IL-1β with/without dexamethasone. Glucocorticoid receptor antagonist, RU486, was used to see the role of dexamethasone. PD98059 (an extracellular signal-regulated kinases [ERKs] inhibitor), SB203580 (a p38 mitogen-activated protein kinases [MAPK] inhibitor), SP600125 (a c-Jun N-terminal kinase [JNK] inhibitor) were also used to see the role of MAPKs signaling pathway(s) in IL-1β-induced MMP-9 expression in HEI-OC1 cells. Reverse transcription-polymerase chain reaction and gelatin zymography were used to measure mRNA expression level of MMP-9 and activity of MMP-9, respectively. Results Treatment with IL-1β-induced the expression of MMP-9 in a dose- and time-dependent manner. IL-1β (1 ng/mL)-induced MMP-9 expression was inhibited by dexamethasone. Interestingly, p38 MAPK inhibitor, SB203580, significantly inhibited IL-1β-induced MMP-9 mRNA and MMP-9 activity. However, inhibition of JNKs and ERKs had no effect on the IL-1β-induced MMP-9 expression. Conclusion These results suggest that the pro-inflammatory cytokine IL-1β strongly induces MMP-9 expression via activation of p38 MAPK signaling pathway in HEI-OC1 cells and the induction was inhibited by dexamethasone.

The Expression of AGO2 and DGCR8 in Idiopathic Sudden Sensorineural Hearing Loss

Objectives The microRNAs have been implicated in the development and function of the inner ear, especially in contribution to hearing. However, the impact of idiopathic sudden sensorineural hearing loss (SSNHL) on expression of miRNA biogenesis-related components has not been established. To investigate the regulations of microRNA (miRNA) biogenesis-related components, argonaute 2 (AGO2) and DiGeorge syndrome critical region gene 8 (DGCR8) mRNA expression in SSNHL and to evaluate the value of clinical parameters on their expression. Methods Thirty-seven patients diagnosed with SSNHL and fifty-one healthy volunteers were included in this study. We measured mRNA expression levels of AGO2 and DGCR8 in whole blood cells but erythrocytes of patients with SSNHL and controls, using reverse transcription and real-time polymerase chain reaction analysis. Results The mRNA expression level of AGO2 is upregulated in SSNHL. The expression level of AGO2 was significantly correlated with that of DGCR8 in both patients with SSNHL and controls. Expression level of AGO2 in SSNHL was correlated with white blood cell counts. Conclusion This study demonstrated for the first time that the AGO2 mRNA expression level was upregulated in SSNHL, suggesting its important role in pathobiology of SSNHL development.

Staging in vestibular schwannoma surgery: a modified technique.

The authors herein propose the staged excision as a novel strategy to preserve facial nerve and minimize complication during microsurgery of large vestibular schwannoma (VS). At the first stage, for reducing mass effect on the brain stem and cerebellum, subtotal tumor resection was performed via a retrosigmoid craniotomy without intervention of meatal portion of tumor. With total resection of the remaining tumor, the facial nerve was decompressed and delineated during the second stage translabyrinthine approach at a later date. A 38-year-old female who underwent the staging operation for resection of her huge VS is illustrated.

The Feasibility of a Modified Exclusive Endoscopic Transcanal Transpromontorial Approach for Vestibular Schwannomas

Objective We evaluated the feasibility of an exclusive endoscopic transcanal transpromontorial approach (EETTA) for the treatment of small vestibular schwannomas (VSs) limited to the internal auditory canal (IAC), and introduced a modification without external auditory canal closure. Methods Between June 2016 and June 2017, seven patients with VS underwent surgery using a modified EETTA. Treatment outcomes, including efficacy of tumor resection, preservation of function, operation time, and quality of life (QOL), were evaluated. Results The patients preoperatively exhibited Koos Grade I/II tumors and severe‐to‐profound hearing loss. Gross total resection was accomplished in all cases. There were no major complications, and all patients exhibited normal facial nerve function immediately after surgery. The mean follow‐up period was 12.9 months. The operation time (average 196.3 ± 64.9 minutes) and hospitalization period (average 7.4 ± 1.0 days) were favorable. Short Form‐36 scores for QOL showed unremarkable results compared with previous reports. Conclusions The modified EETTA was effective in the removal of VSs in the IAC. It can be an alternative surgical option for small VSs.