4 Laryngoscope, 127:2382-2388, 2017.

Integrity of the membranous labyrinth barrier system is of critical importance, which promotes inner ear homeostasis and maintains its features. The membranous labyrinth barrier system is divided into several subsets of barriers which, although independent from each other, are interrelated. The same substance may demonstrate different permeability characteristics through different barriers and under different conditions, while different substances can have different permeability features even in the same barrier under the same condition. All parts of the membranous labyrinth barrier structure, including their morphology, enzymes and channel proteins, and theirs permeability characteristics under various physiological and pathological conditions are reviewed in this paper. Infections, noise exposure, ototoxicity may all increase permeability of the barriers and lead to disturbances in inner ear homeostasis.

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Objective This study was performed to evaluate the prevalence and clinical importance of elevated cerebrospinal fluid (CSF) pressure among patients with pulse-synchronous tinnitus. Methods Nineteen patients underwent height and weight measurements, routine otologic examinations, ear computed tomography, brain magnetic resonance imaging, fundus examination, and tinnitus score assessment. We analyzed the data with Fisher’s exact test, the t-test, and Pearson’s correlation. Results The mean age of the 19 patients was 39.2 ± 8.1 years (range, 27–54 years), and the mean body mass index was 22.2 ± 1.6 kg/m2 (range, 19.9–24.6 kg/m2). The proportion of patients with elevated CSF pressure was 68%. No significant correlation between the severity of tinnitus and CSF pressure was found. Lumbar puncture and oral administration of diuretics resulted in significant improvement in tinnitus. Conclusions If detailed physical and imaging examinations fail to detect the definite cause of pulse-synchronous tinnitus, a routine lumbar puncture should be performed to measure the CSF pressure. Elevated CSF pressure should be suspected in patients with pulse-synchronous tinnitus.

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The purpose of this study is to investigate what characteristics of tinnitus in patients with chronic otitis media was reduced after tympanoplasty and to assess the relationship between post-operative tinnitus reduction and pre-operative tinnitus tone, tinnitus duration, post-operative hearing recovery, and tympanogram. Medical records were prospective between March 2013 and May 2016. Audiologic evaluation by pure tone audiometry and acoustic impedance and tinnitus assessment using scores on the Tinnitus Handicap Inventory (THI) was conducted preoperatively and 6 months post-operatively. The data were analyzed using the Wilcoxon test, Student's and paired t test, and ANOVA. The pre-operative incidence of tinnitus in patients with COM was 47%. There was a very significant difference between pre-operative and post-operative mean THI scores (p < 0.05). Tinnitus was reduced or alleviated in 83% of tinnitus patients. Pre-operative low-tone tinnitus was significantly reduced 6 months after surgery. After surgery, air-conducted hearing improvement at 250, 500, and 1000 Hz in the tinnitus significant recovery group was greater than the tinnitus non-significant recovery group (p < 0.05). Tinnitus reduction in tympanogram A was significantly greater than in tympanograms B or C (p < 0.05). There was no statistically significant correlation between tinnitus duration and tinnitus reduction (p > 0.05). There was no significant effect of presence cholesteatoma and dry period on the gain THI (p > 0.05). The types of tympanoplasty had no effect on tinnitus improvement (p > 0.05). No patients experienced new tinnitus after surgery. Following tympanoplasty, most patients experienced a reduction in tinnitus. Pre-operative low-tone tinnitus is easier to reduce after tympanoplasty. Post-operative normal tympanogram and improved low-frequency AC hearing were important to tinnitus reduction.

Objectives: n-Hexane, a common industrial organic solvent, causes multiple organ damage, especially neurotoxicity, which is proved to be caused by its metabolite 2,5-hexanedione (2,5-HD). We previously showed that 2,5-HD induced apoptosis of rat bone marrow mesenchymal stem cells (BMSCs). In the current study, we explored the mechanism of 2,5-HD-induced apoptosis, especially the role played by reactive oxygen species (ROS). Methods: Intracellular ROS levels after 2,5-HD treatment were measured by the dichloro-dihydro-fluorescein diacetate (DCFH-DA) method, and the antioxidant N-acetyl cysteine (NAC) was used to scavenge ROS. Apoptosis, mitochondrial membrane potential (MMP), and caspase-3 activity were measured after 2,5-HD exposure with or without NAC pretreatment. Results: In rat BMSCs, 20 mM 2,5-HD significantly increased ROS levels and apoptosis. In addition, MMP activity was decreased and caspase-3 activity was increased. With NAC pretreatment, ROS increases were prevented, cells were rescued from apoptosis, and both MMP and caspase-3 activity returned to normal levels. Western blotting analysis of malondialdehyde-modified proteins and superoxide dismutase (SOD) 1 showed that after 2,5-HD exposure, BMSCs had oxidative damage and abnormal SOD1 expression. These returned to normal when cells were pretreated with NAC in addition to 20 mM 2,5-HD. Furthermore, the expressions of NF-κB p65/RelA and phospho-NF-κB p65/RelA (Ser536) were suppressed after 2,5-HD exposure and restored by NAC pretreatment. Conclusions: 2,5-HD-induced apoptosis in rat BMSCs is potentially mediated by excessive ROS production.

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