Evaluation of the reliability and validity of the upright head roll test for lateral semicircular canal benign paroxysmal positional vertigo.

BACKGROUND: The upright head roll test (UHRT) is a recently introduced diagnostic maneuver for lateral semicircular canal benign paroxysmal positional vertigo (LSC-BPPV). OBJECTIVE: This study aimed to evaluate the reliability and validity of the UHRT. METHODS: Two separate studies were conducted. Study 1 analyzed 827 results of videonystagmography (VNG) to assess UHRT reliability, and Study 2 analyzed 130 LSC-BPPV cases to evaluate UHRT validity. RESULTS: The inter-test reliability between UHRT and the supine head roll test (SHRT) showed substantial agreement (Cohen's kappa = 0.753) in direction-changing positional nystagmus (DCPN) and almost perfect agreement (Cohen's kappa = 0.836) in distinguishing the direction of DCPN. The validity assessment of UHRT showed high accuracy in diagnosing LSC-BPPV (80.0%) and in differentiating the variant types (74.6%). UHRT was highly accurate in diagnosing the canalolithiasis type in LSC-BPPV patients (Cohen's kappa = 0.835); however, it showed only moderate accuracy in diagnosing the cupulolithiasis type (Cohen's kappa = 0.415). The intensity of nystagmus in UHRT was relatively weaker than that in SHRT (P < 0.05). CONCLUSION: UHRT is a reliable test for diagnosing LSC-BPPV and distinguishing subtypes. However, UHRT has a limitation in discriminating the affected side owing to a weaker intensity of nystagmus than SHRT.

The Effects of Music-Based Auditory Training on Hearing-Impaired Older Adults With Mild Cognitive Impairment.

OBJECTIVES: The present study aimed to determine the effect of music-based auditory training on older adults with hearing loss and decreased cognitive ability, which are common conditions in the older population. METHODS: In total, 20 older adults diagnosed with both mild-to-moderately severe hearing loss and mild cognitive impairment (MCI) participated. Half of this group were randomly assigned to the auditory training group (ATG), and the other half were designated as the control group (CG). For the ATG, a 40-minute training session (10 minutes for singing a song, 15 minutes for playing instruments, and 15 minutes for playing games with music discrimination) was conducted twice a week for 8 weeks (for a total of 16 sessions). To confirm the training effects, all participants were given tests pre- and post-training, and then a follow-up test was administered 2 weeks after the training, using various auditory and cognitive tests and a self-reporting questionnaire. RESULTS: The ATG demonstrated significant improvement in all auditory test scores compared to the CG. Additionally, there was a notable enhancement in cognitive test scores post-training, except for the digit span tests. However, there was no statistically significant difference in the questionnaire scores between the two groups, although the ATG did score higher post-training. CONCLUSION: The music-based auditory training resulted in a significant improvement in auditory function and a partial enhancement in cognitive ability among elderly patients with hearing loss and MCI. We anticipate that this music-based approach will be adopted for auditory training in clinical settings due to its engaging and easy-to-follow nature.

Association between HbA1c and hearing loss: a tertiary care center-based study.

The purpose of this study was to investigate the correlation between glycated hemoglobin (HbA1c) levels and hearing loss (HL) using data from a tertiary hospital. Our hypothesis regarding the relationship between HL and HbA1c levels was that elevated HbA1c levels are associated with an increased risk of HL. We retrospectively reviewed the medical charts of patients diagnosed with sensorineural HL or diabetes between 2006 and 2021 at the Catholic Medical Center (CMC). Data were collected from the CMC's Clinical Data Warehouse. Participants were selected from patients who were prescribed pure-tone audiometry and an HbA1c blood test. The survey was completed for 5287 participants. The better ear pure-tone audiometry (PTA) for air conduction thresholds at 500, 1000, 2000, and 4000 Hz was calculated. Sensorineural HL was defined as a better ear PTA of 25 dB or higher. We used the HbA1c level as a diagnostic criterion for diabetes. The following criteria were used to define the HbA1c level: normal, HbA1c level below 5.6%; prediabetes, level between 5.6 and 6.4%; and diabetes, level of 6.5% or more. Among 5287 participants, 1129 were categorized as normal, 2119 as prediabetic, and 2039 as diabetic. The diabetic group was significantly older (p < 0.05). The PTA also significantly deteriorated in the diabetes group (p < 0.05). We analyzed the effects of age, sex, and HbA1c level on frequency-specific hearing using multiple regression. The hearing thresholds at all frequencies deteriorated significantly with increasing age and HbA1c level (p < 0.05). A case-control study was also performed to facilitate a comprehensive comparison between distinct groups. The participants were categorized into two groups: a case (PTA > 25 dB) and control group (PTA ≤ 25 dB), based on their PTA threshold of four frequencies. After adjusting for age and sex, we found no significant odds ratio (OR) of HL between the prediabetes group and the normal group. Notably, the OR of HL was significantly higher in the diabetes group with each PTA threshold and frequency. The 6.3% HbA1c level cutoff value was determined by analyzing the receiver operating characteristic curve for predicting hearing impairment > 25 dB. Diabetes was associated with hearing loss in all frequency ranges, particularly at high frequencies. Screening for HL is strongly recommended for patients with elevated HbA1c levels.

The cover of an ear thermometer probe as a split-thickness skin graft mold in external auditory canal reconstruction.

Maintaining the patency of the external auditory canal (EAC) during reconstruction is important because of its physiological role in hearing and immunological protective functions. The curved shape of the EAC presents a challenge when performing a skin graft. One of the key points for a successful skin graft is to ensure compression on the wound bed, and many novel methods, including prefabricated ear molds, have been reported for this purpose. In this study, we present a case of a skin graft performed to reconstruct a skin defect following excision of actinic keratosis in the EAC, using the cover of an ear thermometer probe as a mold for the graft to match the curvature of the EAC. This is an economical and practical method for secure compression dressing of a skin graft in the EAC.

Association of dietary factors with noise-induced hearing loss in Korean population: A 3-year national cohort study.

Noise-induced hearing loss (NIHL) is a hearing impairment (HI) caused by various clinical factors. Identifying the relationship between NIHL and nutrient consumption could help in reducing the prevalence of hearing loss. The aim of this study was to analyze the relationship between NIHL and dietary factors using data of the Korea National Health and Nutrition Examination survey (KNHANES). The data were collected from The Fifth KNHANES 2010-2012. The survey was taken by a total of 10,850 participants aged 20-65 years. Air conduction audiometry was measured at 500, 1000, 2000, and 4000 Hz in both ears. Metabolic syndrome, noise exposure, alcohol consumption, smoking, income level, marital status, and nutritional intake were evaluated. The differences between non-HI and HI participants in the noise-exposed group showed statistically significant differences in age, sex, marital and smoking status, alcohol consumption, and fasting glucose and triglyceride levels (p<0.05). In a multiple regression analysis of the noise-exposed group, age showed a significant association with HI (OR: 0.604; 95% CI: 0.538-0.678) after adjusting for confounders. In multivariate analysis for dietary factors affecting HI in noise-exposed groups, retinol (OR: 1.356; 95% CI: 1.068-1.722), niacin (OR: 1.5; 95% CI: 1.022-2.201), and carbohydrates (OR: 0.692; 95% CI: 0.486-0.985) showed a significant association with NIHL. Age was identified as the only factor significantly affecting NIHL. When the dietary factors of the noise-exposed group were analyzed, high intake of niacin and retinol and low intake of carbohydrates appeared to reduce the risk of hearing loss.

Analysis of the Knowledge, Attitudes, and Practice Model of Healthcare Professionals on Hearing Loss at Elderly Dementia Residences in Korea.

Due to a lack of knowledge about age-related hearing loss, its early identification and appropriate intervention are not being carried out in the field of dementia care. Since the untreated hearing loss of the elderly leads to a more rapid cognitive decline, the present study aimed to understand the hearing-related knowledge, attitudes, and practices of healthcare professionals in long-term care (LTC) facilities in Korea. A total of 557 workers (104 facility managers and 453 healthcare professionals) in residential LTC participated in this cross-sectional multicenter survey study. The Korean version of the knowledge, attitudes, and practice (KAP) on-line survey with a five-point scale or yes/no response was applied as the experimental tool. The results of structural equation modeling showed that knowledge significantly affected the attitudes and health-seeking practices of the facility manager, and allied healthcare professionals demonstrated similar results, which showed the significant effects of that knowledge on attitudes and health-seeking practices. This clearly indicated that sufficient knowledge is the driving force for the health-seeking practices and positive attitudes of both the facility manager and the healthcare professionals. Thus, we suggest that a further step, such as the development of comprehensive and professional guidelines regarding hearing care information for these professionals in residential LTC facilities, should be followed, and believe that this effort could lead to improving hearing-related knowledge, attitudes, and practices in order to clinically and politically care for the elderly population.

The risk of laryngitis with herpes zoster infection: A nested case-control study using data from the Korean National Sample Cohort.

BACKGROUND: Whether herpes zoster infection (HZI) affects laryngitis incidence remains unknown. OBJECTIVE: The purpose of this population-based retrospective study was to analyze the relationship between laryngitis and HZI using data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort. METHODS: This study analyzed 1,197,093 medical claim codes from 2018. Patients with HZI (ICD-10: B02) were retrospectively identified. Laryngeal diseases were defined by ICD-10 codes for five subgroups: 1) malignant disease, 2) benign disease, 3) vocal cord palsy, 4) inflammatory disease, and 5) reflux disease. RESULTS: Among the Korean population older than 20 years, 12,809 experienced HZI. Subjects with HZI were more likely to be older (mean age: 51.54 years vs. 48.06 years, p <0.0001). The proportion of subjects with laryngeal disease was higher in those with HZI than in those without HZI (55.55% vs. 41.37%, p <0.0001). Laryngeal disease was significantly associated with HZI in multiple regression analysis (odds ratio (OR) = 1.77, 95% confidence interval: 1.71-1.84) after adjusting for age, sex, hypertension, diabetes, dyslipidemia, ischemic heart disease, cerebral stroke, and depression. Among laryngeal disease subgroups, inflammatory disease (OR = 1.05; 95% CI: 1.01-1.09) and reflux (OR = 1.20; 95% CI: 1.15-1.25) were associated with HZI. CONCLUSIONS: HZI is independently associated with laryngitis. Results of this study have implications for etiological investigations and prevention strategies for laryngitis.

Rate and Product Studies with 1-Adamantyl Chlorothioformate under Solvolytic Conditions.

A study was carried out on the solvolysis of 1-adamantyl chlorothioformate (1-AdSCOCl, 1) in hydroxylic solvents. The rate constants of the solvolysis of 1 were well correlated using the Grunwald-Winstein equation in all of the 20 solvents (R = 0.985). The solvolyses of 1 were analyzed as the following two competing reactions: the solvolysis ionization pathway through the intermediate (1-AdSCO)+ (carboxylium ion) stabilized by the loss of chloride ions due to nucleophilic solvation and the solvolysis-decomposition pathway through the intermediate 1-Ad+Cl- ion pairs (carbocation) with the loss of carbonyl sulfide. In addition, the rate constants (kexp) for the solvolysis of 1 were separated into k1-Ad+Cl- and k1-AdSCO+Cl- through a product study and applied to the Grunwald-Winstein equation to obtain the sensitivity (m-value) to change in solvent ionizing power. For binary hydroxylic solvents, the selectivities (S) for the formation of solvolysis products were very similar to those of the 1-adamantyl derivatives discussed previously. The kinetic solvent isotope effects (KSIEs), salt effects and activation parameters for the solvolyses of 1 were also determined. These observations are compared with those previously reported for the solvolyses of 1-adamantyl chloroformate (1-AdOCOCl, 2). The reasons for change in reaction channels are discussed in terms of the gas-phase stabilities of acylium ions calculated using Gaussian 03.

Association between Hearing Loss and Cognitive Disorder: A Nationwide Population-Based Study.

PURPOSE: To investigate the relationship between hearing loss and cognitive disorder with memory dysfunction in South Korea using data from the Korean Health Insurance claims database for 2009-2015. MATERIALS AND METHODS: We analyzed cross-sectional data of 66-year-old individuals who completed the Korea National Health and Nutrition Examination Surveys. Auditory function was evaluated using pure-tone audiometric testing. Cognitive disorder with memory dysfunction was assessed using standardized scores of the Prescreening Korean Dementia Screening Questionnaire. RESULTS: Among 1815835 participants at the age of 66 years, the prevalence of unilateral hearing loss was 5.84%, and that of bilateral hearing loss was 3.40%. The normal cognitive group comprised 86.35% of the participants, and the high-risk group for cognitive disorder with memory dysfunction totaled 13.65% of the participants. The bilateral hearing loss group had the highest percentage of subjects who responded "sometimes or frequently" to all five questions about cognitive disorder with memory dysfunction, compared to the normal hearing group or the unilateral hearing loss group. After adjusting for sex, smoking status, alcohol intake, exercise, income, diabetes, hypertension, dyslipidemia, and depression, the odds ratios for cognitive disorder with memory dysfunction was 1.183 [95% confidence interval (CI): 1.163-1.203] for bilateral hearing loss and 1.141 (95% CI: 1.126-1.156) for unilateral hearing loss, compared to the normal cognitive group. CONCLUSION: Hearing loss has a significant effect on cognitive function in the Korean population. In our study, individuals with bilateral hearing loss showed poorer cognitive function than those with unilateral hearing loss.

The Long-Term Stability of Fat-Graft Myringoplasty in the Closure of Tympanic Membrane Perforations and Hearing Restoration.

BACKGROUND/AIMS: This study was conducted to evaluate the long-term stability of fat-graft myringoplasty (FGM) for chronic tympanic membrane perforations, analyzing the perforation closure rate and re-gained hearing outcome with respect to the size and location of the perforations. METHODS: Between August 2007 and June 2018, a total of 193 patients who underwent FGM due to chronic tympanic membrane perforation at a tertiary referral center were enrolled and analyzed. RESULTS: The mean follow-up was 14.6 months (range 6-39). The complete perforation closure rate after FGM was 89.6%, with no statistical difference among the perforation size groups. The mean postoperative air-bone gap (ABG) was 11.0 dB and mean ABG improvement was 4.9 dB. CONCLUSION: Our FGM technique had a favorable tympanic closure rate for small to large perforations, and yielded relatively good hearing improvement in the mid-size perforation cases over long-term follow-up periods. According to the topographic evaluation of FGM, this procedure resulted in a reliable perforation closure rate and audiological results regardless of the perforation site.

Age-related hearing loss in the Korea National Health and Nutrition Examination Survey.

OBJECTIVES: Age-related hearing loss (ARHL), also known as presbycusis, is a chronic disorder characterized by impairment of the transduction of acoustic signals. This study analysed the prevalence and demographic characteristics of ARHL in the Korean population. METHODS: We used the data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2009 to 2012 and analysed the association between age and hearing impairment. A total of 16,799 adults were selected for the current study. Physical examinations, blood tests, otoscopic examinations, and hearing tests were performed. The demographic variables included age, gender, obesity, economic status, education level, noise exposure history, and underlying diseases. RESULTS: Among 16,799 participants, the prevalence of unilateral hearing loss was 8% (1,349 people), and bilateral hearing loss was 5.9% (989 people). Men were 53.4% more likely to have hearing loss than women. Age and underlying diseases, like hypertension, diabetes, and abdominal obesity, were significantly associated with hearing loss (P < 0.0001). Further, mental health factors, such as cognitive function, depression, and suicidal ideation, were related to hearing loss. The prevalence of hearing loss increased with advancing years, especially in the high frequency of 6 kHz, with a sharply increase in patients aged 65 and over. CONCLUSION: The analysis of auditory performance in the Korean population confirmed the association of high-frequency hearing loss with advancing age. A threshold of 6 kHz should be included to correctly diagnose hearing impairment in elderly patients. Patients with ARHL should be provided with suitable aural rehabilitation that includes active high-frequency control.

Clinical efficacy of standard simple elliptical incision following drain-less and subcutaneous suture technique in preauricular sinus surgery.

BACKGROUND: The purpose of this study was to review our surgical strategy and outcomes of drain-less, subcutaneous suture technique in standard simple elliptical incision on preauricular sinus (PAS) cases. METHODS: The clinical records of 198 patients (247 ears) with PASs who were operated via standard simple elliptical incision with drain-less, subcutaneous suture technique by a single surgeon (K.H.P.) between January 2008 and December 2018 were reviewed for analysis. Patients' demographics, location of PASs, previous incision and drainage (I&D) history, previous surgical excision history, duration of follow-up, postoperative infection after surgery, and recurrence after surgery were analysed. RESULTS: Out of 247 PASs, 18 (7.3%) cases had postoperative infections and 11 (4.5%) cases showed recurrence. Postoperative infection rate were higher in previous I&D groups (PIDGs, 9.8%) and previous fistulectomy groups (PFGs, 10%), and also recurrence rates of PFGs (10%) was higher than those of fresh cases. However, there were no statistically significant differences between these groups. In addition, PAS patients with postoperative complications such as infection and recurrence were more common in male patients. CONCLUSION: We report a method of drain-less standard simple elliptical incision for the surgical removal of PAS and the outcomes of the surgery. Our method showed a low recurrence rate and low chance of wound infection postoperatively not only in fresh cases but also in pre-operative I&D cases and even previous fistulectomy cases. In conclusion, our method is proposed as an effective and safe method in all kind of patient groups, without presenting post-operative discomfort to patients.

The Effect of the ortho Nitro Group in the Solvolysis of Benzyl and Benzoyl Halides.

A kinetic study was carried out on the solvolysis of o-nitrobenzyl bromide (o-isomer, 1) and p-nitrobenzyl bromide (p-isomer, 3), and o-nitrobenzoyl chloride (o-isomer, 2) in a wide range of solvents under various temperatures. In all of the solvents without aqueous fluoroalcohol, the reactions of 1 were solvolyzed at a similar rate to those observed for 3, and the reaction rates of 2 were about ten times slower than those of the previously studied p-nitrobenzoyl chloride (p-isomer, 4). For solvolysis in aqueous fluoroalcohol, the reactivity of 2 was kinetically more reactive than 4. The l/m values of the extended Grunwald-Winstein (G-W) equation for solvolysis of 1 and 2 in solvents without fluoroalcohol content are all significantly larger than unity while those in all the fluoroalcohol solvents are less than unity. The role of the ortho-nitro group as an intramolecular nucleophilic assistant (internal nucleophile) in the solvolytic reaction of 1 and 2 was discussed. The results are also compared with those reported earlier for o-carbomethoxybenzyl bromide (5) and o-nitrobenzyl p-toluenesulfonate (7). From the product studies and the activation parameters for solvolyses of 1 and 2 in several organic hydroxylic solvents, mechanistic conclusions are drawn.

The Clinical Characteristics and Surgical Outcomes of Carcinoma of the External Auditory Canal: A Multicenter Study.

OBJECTIVE: To analyze the clinical characteristics and evaluate the surgical outcomes of carcinoma of the external auditory canal (CEAC). MATERIALS AND METHODS: Overall, 31 patients from four multicenter hospitals, who were diagnosed and surgically treated for CEAC in 2009-2014, were enrolled for this retrospective study. Medical records were reviewed to determine cancer stage according to the Pittsburgh classification. Clinical data of age, sex, site, initial symptoms, surgery extent, postoperative complications including recurrence, follow-up period, and current patient status were collected for analysis. Five-year cumulative survival rate was obtained using Kaplan-Meier method. RESULTS: At initial diagnosis, 22 patients were in the early stages (stage I: 15; stage II: 7) and 9 patients were in the advanced stages (stage III: 1; stage IV: 8). Lymph node metastasis was present in 5 patients and distant metastasis in 2. Of the 31 patients, 4 patients died (stage II: 1, stage IV: 3) during the follow-up period. Early-stage patients showed 100% 5-year estimated cumulative survival rate, whereas the advanced-stage patients showed 5-year estimated survival rate of 53.6% (p=.006). The overall survival rate of all enrolled patients was 90.3%. Although 5-year estimated disease-free survival rate of stage I was 100.0%, that for stage II was low at 30.0% because of considerable recurrences. CONCLUSION: The results of this multicenter study suggest that more aggressive treatment modality, including adjuvant therapy, is necessary for patients with CEAC with Pittsburgh stage II or more.

Update on Bone-Conduction Auditory Brainstem Responses: A Review.

Auditory brainstem responses (ABR) have been used as a powerful and the most common objective tool to evaluate hearing sensitivity and to diagnose the types of hearing loss and neurological disorders, through the auditory peripheral pathway to a central level of the brainstem, since 1971. Although bone-conduction (BC) ABR could be an alternative to air-conduction (AC) ABR, as the former overcomes some limitations of the latter, the majority of clinicians rarely utilize it due to a lack of knowledge and no routine test administration. This review presents the weaknesses of AC ABR that apply to all clinical population, and discusses the development of BC ABR. The optimal placements of bone oscillators to obtain favorable clinical outcomes in infants, children, and adults, and the appropriate stimuli for BC ABR are examined. While providing absolute thresholds and latencies of BC ABR based on previous studies compared to AC ABR, this review includes clinical data of infants and young children with both normal hearing in terms of maturation, and with pathology such as congenital external auditory canal atresia. We recommend the future clinical application of BC ABR for candidacy as well as for patients with BC hearing implants.

Clinical Safety and Efficacy of Autologous Bone Marrow-Derived Mesenchymal Stem Cell Transplantation in Sensorineural Hearing Loss Patients.

Stem cell transplantation represents a promising therapy for several degenerating and necrotic diseases. In several animal studies, we could find hearing restoration after inoculation of the mesenchymal stem cells' as well as mesenchymal stem cells' differentiation of hair cells and spiral ganglion. But until now, no clinical study has been reported directly for the human being. In this pilot studies, we applied mesenchymal stem cells to human beings trans-venously. Although we verified the safety of the autologous bone marrow stem cell transplantation in sensorineural hearing loss patients but we could not achieve significant improvement in hearing.

Regenerative efficacy of mesenchymal stromal cells from human placenta in sensorineural hearing loss.

INTRODUCTION: Hearing loss is a common chronic disorder characterized by decline of auditory function. The global population have suffered from deafness and the transplantation of stem cells is regarded as a therapeutic strategy for this disease. METHODS: We collected placenta from a total of 13 samples of full term pregnant women and isolated MSCs derived from human placenta and transplanted MSCs on deaf animal model. The normal group and the sensorineural hearing loss (SNHL) group and the experimental (transplanted MSCs) group were compared and estimated hearing level using auditory brainstem response (ABR) recordings and the otoacoustic emission (OAE) test. RESULTS: ABR threshold value and DPOAE level showed that MSCs transplantation groups was improved than the SNHL group. And the number of spiral ganglion neurons were increased in all turn of the cochlea. And there was no evidence of acute immunological rejection and inflammation response was not observed. DISCUSSION: This study is to evaluate regenerative efficacy of hearing loss by transplanting mesenchymal stromal cells (MSCs) derived from human placenta (amnion and chorion) in deaf animal model. We identified that MSCs transplantation restored auditory impairment and promoted cell regeneration. We hope to overcome sensorineural hearing loss by transplanting stem cells such as mesenchymal stromal cells (MSCs) from easily accessible adult stem cell source in placenta.

In Vitro Differentiation of Human Wharton's Jelly-Derived Mesenchymal Stem Cells into Auditory Hair Cells and Neurons.

OBJECTIVE: We attempted to induce mesenchymal stem cells (MSCs) from human Wharton's jelly (WJ) to differentiate into neuronal progenitor cells, neurons, and auditory hair cells. MATERIALS AND METHODS: MSCs were isolated from WJ from human umbilical cords and cultured in medium containing epidermal growth factor and basic fibroblast growth factor. Differentiation into hair cells and neurons was induced using a neurobasal medium containing glial cell-derived neurotrophic factor, brain-derived neurotrophic factor, and neurotrophic factor 3. Fluorescence-activated cell sorting (FACS), immunocytochemistry, and reverse transcription polymerase chain reaction were performed to characterize the differentiated auditory hair cells and neurons. RESULTS: MSCs isolated from human WJ were confirmed by FACS. Double immunocytochemistry confirmed the expression of the hair cell markers myosin VIIA and TRPA1 and the functional marker C-terminal binding protein 2. Differentiation into neurons was revealed using neurofilament and ßIII-tubulin markers. Gene expression of neuronal lineage-specific markers confirmed the neuronal differentiation state. CONCLUSION: MSCs from human WJ can be successfully induced to differentiate into auditory hair cells and neurons in vitro.

Development of a drug delivery system for the inner ear using poly(amino acid)-based nanoparticles.

CONTEXT: Local delivery systems for treatment of intractable inner ear disorders have been attempted by many investigators. OBJECTIVE: To evaluate the permeability and safety of a drug delivery system for the inner ear using a poly(2-hydroxyethyl aspartamide) (PHEA) polymersome. MATERIALS AND METHODS: One-month-old male C57/BL6 mice were used. We administered the same amount of the fluorescent dye, Nile red, into the middle ear in two forms: loaded in PHEA polymersomes (NP group) or diluted in ethanol (NR group). At 1 day after administration, we harvested the cochlea and counted visible red particles in the tissues of cochlea under confocal microscopy and compared the groups. In a safety evaluation, 1 week after the same surgery, we conducted hearing tests and histological evaluations of the bulla and cochlea, and compared the results with those of the sham operation and negative control groups. RESULTS: In terms of permeability, the number of red particles in the organ of Corti was increased significantly in the NP group, and three subjects in the NP group showed uptake of red particles in inner hair cells. However, there was no statistically significant difference in the observations in the lateral wall or modiolus. In safety tests, the NP and sham-operation groups showed decreased DPOAE responses and mildly swollen middle ear mucosa, compared with the negative control group, which was thought to be the result of postoperative changes. CONCLUSIONS: PHEA nanoparticles may have utility as a drug carrier into the inner ear in terms of both permeability and safety.

Proteomic analysis of vestibular schwannoma: conflicting role of apoptosis on the pathophysiology of sporadic vestibular schwannoma.

HYPOTHESIS: In this study, we investigated the pathophysiology and mechanism underlying sporadic forms of vestibular schwannoma (VS) by comparing VS tissue with normal nerve tissue using proteomics. BACKGROUND: Proteomic analysis by two-dimensional electrophoresis and matrix-assisted laser desorption and ionization time-of-flight mass spectrometry facilitates identification and characterization of specific proteins related to the pathogenesis of various diseases. METHODS: Proteins were extracted from two vestibular nerve specimens and two VS specimens and analyzed in parallel using two-dimensional electrophoresis. We then analyzed 29 spots that were differentially expressed using matrix-assisted laser desorption and ionization time-of-flight mass spectrometry. Upregulated proteins associated with apoptosis were confirmed by Western blot analysis and immunohistochemistry. RESULTS: Twenty-nine proteins showing significant changes in the expression level between VS tissue and normal nerve tissue were identified. Of these, seven proteins were related to apoptosis. CONCLUSION: Our findings indicate that apoptosis is associated in a complex manner with the pathophysiology of VS. The suppression of apoptosis is presumably involved in tumor occurrence and, conversely, increased apoptotic expression may contribute to the slow tumor growth rate and may be correlated with the Antoni type B area.