Clinical effects of non-pharmaceutical interventions for COVID-19 on other nationally notifiable infectious diseases in South Korea.

BACKGROUND/AIMS: This study aimed to assess the impact of non-pharmaceutical interventions (NPIs) implemented during the COVID-19 pandemic on nationally notifiable infectious diseases (NNIDs) in South Korea. METHODS: Long-term data on seven NNIDs from 2018 to 2021 were analyzed to identify trends and change points using a change point detection technique. The timings of the NPI implementations were compared to the identified change points to determine their association. RESULTS: Varicella, mumps, and scarlet fever showed a significant decrease in incidence following the implementation of NPIs during the COVID-19 pandemic. These diseases, which are primarily transmitted through respiratory droplets, demonstrated a clear response to NPIs. However, carbapenem-resistant Enterobacterales (CRE) showed an increasing trend unrelated to the timing of NPI implementation, suggesting the complex nature of controlling healthcare-associated infections. Hepatitis A, hepatitis C, and scrub typhus did not show significant changes associated with NPIs, likely due to their non-respiratory route of transmission. CONCLUSION: NPIs effectively controlled NNIDs, particularly those transmitted through respiratory infections. However, the impact varied depending on the disease. Understanding the effectiveness and limitations of NPIs is crucial for developing comprehensive public health strategies during infectious disease outbreaks.

Social distancing during the COVID-19 pandemic: Potential impact and correlation with asthma.

BACKGROUND: Non-pharmaceutical interventions have been implemented globally to control the COVID-19 pandemic and have been shown to alleviate both allergies and respiratory infections. Although mask-wearing is an accepted non-pharmaceutical intervention, the effects of social distancing have not been thoroughly evaluated. OBJECTIVES: To evaluate the effects of social distancing on asthma trends in Seoul, South Korea. METHODS: This study included data from the National Health Insurance Service of South Korea, covering approximately 10 million people in Seoul. Daily and monthly data of patients with asthma from 2018 to 2021 were examined, and the degree of social distancing performance was measured using the number of subway users as an index. Pearson's correlation coefficient was used to determine the relationship between the two indices. The change-point detection technique, cross-correlation, and Granger causality method were used to assess the temporal causality between social distancing and asthma. RESULTS: The number of patients with asthma decreased by 42.4 % from 2019 to 2020, while that of subway users decreased by 26.3 % during this period. Pearson's correlation analysis revealed significant positive correlations. Asthma and subway users showed a significant change in incidence following the implementation of social distancing; subway users showed a causal relationship with patients with asthma. CONCLUSION: Our results showed that the number of subway users decreased after the implementation of strict social distancing, coinciding with a decrease in the number of patients with asthma. These findings suggest that social distancing measures implemented to control COVID-19 may reduce the incidence and exacerbation of asthma.

Impact of COVID-19 Pandemic on the Incidence of Pediatric Acute Otitis Media in Seoul, South Korea.

OBJECTIVE: The implementation of nonpharmaceutical interventions (NPIs) for coronavirus disease 2019 (COVID-19) may affect the incidence of infectious diseases. This study aimed to evaluate the changes in the incidence of pediatric acute otitis media (AOM) after the COVID-19 outbreak in Seoul, South Korea. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary referral center. PATIENTS: We ascertained the daily number of COVID-19 and pediatric AOM patients between January 20, 2020, and June 19, 2020. During the same period, the number of children using public transportation was used as an index for implementing NPIs. The same period 1 year ago was set as the control period. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: The differences in the incidence of AOM and implementation of NPIs between the COVID-19 pandemic and control period were analyzed using segmented regression analyses. Negative values of difference meant that the number in the COVID-19 pandemic period declined compared with the control period. RESULTS: The study period was divided into two sections based on the change point of the COVID-19 cases. In the first period, the increased number of COVID-19 cases decreased, and in the second period, the number of COVID-19 cases increased again. Similar trends were observed in the incidence of AOM and NPI implementation. Before the change point, the study found a significant decreasing trend in the differences in pediatric AOM cases and children using public transportation. However, these trends changed after the change point, with a significant increase in both indices. CONCLUSION: Our findings indicate that NPIs for COVID-19 may influence the incidence of pediatric AOM.

Treatment Efficacy of Various Maneuvers for Lateral Canal Benign Paroxysmal Positional Vertigo With Apogeotropic Nystagmus: A Randomized Controlled Trial.

OBJECTIVES: The aim of this study was to determine the most effective treatment approach by comparing the impacts of various otolith reduction techniques in patients with apogeotropic lateral semicircular canal benign paroxysmal positional vertigo (LC-BPPV). METHODS: We performed a multicenter randomized prospective study from January to December 2015, involving 72 consecutive patients with apogeotropic LC-BPPV. The patients were divided into three treatment groups: therapeutic head-shaking (group A), the Gufoni-Appiani maneuver (group B), and the cupulolith repositioning maneuver (CuRM; group C). Each group underwent evaluation and treatment up to the fourth week. Treatment success was defined as the disappearance of positional vertigo and nystagmus. RESULTS: This study included 72 patients (49 male and 23 female), with a mean (±standard deviation) age of 55.4±13.5 years. The mean duration of vertigo experienced prior to treatment was 3.9±4.4 days. The mean latency and duration of nystagmus were 2.7±3.0 seconds and 47.9±15.8 seconds, respectively. The overall treatment frequency was 2.0±0.9. The number of treatments differed significantly among the three groups (P<0.05). After 4 weeks, the success rates for groups A, B, and C were 90.5%, 92.3%, and 100%, respectively. No significant difference was observed in the success rate across treatment. METHODS: and periods (P>0.05). However, CuRM was the only method with a 100% treatment success rate. CONCLUSION: While no clear difference was observed among the three treatments for LC-BPPV, CuRM was found to be superior to the other approaches in the long term.

Machine Learning Models for Predicting the Occurrence of Respiratory Diseases Using Climatic and Air-Pollution Factors.

OBJECTIVES: Because climatic and air-pollution factors are known to influence the occurrence of respiratory diseases, we used these factors to develop machine learning models for predicting the occurrence of respiratory diseases. METHODS: We obtained the daily number of respiratory disease patients in Seoul. We used climatic and air-pollution factors to predict the daily number of patients treated for respiratory diseases per 10,000 inhabitants. We applied the relief-based feature selection algorithm to evaluate the importance of feature selection. We used the gradient boosting and Gaussian process regression (GPR) methods, respectively, to develop two different prediction models. We also employed the holdout cross-validation method, in which 75% of the data was used to train the model, and the remaining 25% was used to test the trained model. We determined the estimated number of respiratory disease patients by applying the developed prediction models to the test set. To evaluate the performance of each model, we calculated the coefficient of determination (R2) and the root mean square error (RMSE) between the original and estimated numbers of respiratory disease patients. We used the Shapley Additive exPlanations (SHAP) approach to interpret the estimated output of each machine learning model. RESULTS: Features with negative weights in the relief-based algorithm were excluded. When applying gradient boosting to unseen test data, R2 and RMSE were 0.68 and 13.8, respectively. For GPR, the R2 and RMSE were 0.67 and 13.9, respectively. SHAP analysis showed that reductions in average temperature, daylight duration, average humidity, sulfur dioxide (SO2), total solar insolation amount, and temperature difference increased the number of respiratory disease patients, whereas increases in atmospheric pressure, carbon monoxide (CO), and particulate matter ≤2.5 µm in aerodynamic diameter (PM2.5) increased the number of respiratory disease patients. CONCLUSION: We successfully developed models for predicting the occurrence of respiratory diseases using climatic and air-pollution factors. These models could evolve into public warning systems.

Development of prediction models for the incidence of pediatric acute otitis media using Poisson regression analysis and XGBoost.

Otitis media has profound health and economic impact, and its occurrence is known to be influenced by air pollution and climate. The purpose of this study was to develop prediction models using climate and air pollution indicators for the occurrence of acute otitis media (AOM). The study was conducted from January 1, 2014, to December 31, 2019, and included pediatric patients (age < 12 years) diagnosed on their emergency room visit in our tertiary medical institution. We obtained data on the weekly number of AOM patients and the weekly average values of air pollution and climate indicators. Poisson regression analysis and eXtreme Gradient Boosting (XGBoost) were used to develop prediction models for the overall pediatric patients and for the patients classified according to sex (male and female) and age (< 2 years and ≥ 2 years). For the overall population, the correlation coefficients between the original and estimated data in the testing set were 0.441 (p < 0.001) and 0.844 (p < 0.001) for the models developed using Poisson regression analysis and XGBoost, respectively. The root-mean-square errors in the testing set were 3.094 and 1.856, respectively. For patients classified according to sex and age, the prediction models developed using XGBoost showed better performance than the models developed using Poisson regression analysis. In conclusion, this study successfully developed prediction models with air pollution and climate indicators for the incidence of pediatric AOM, using XGBoost. This model can be further developed to prevent pediatric AOM.

CS-VIBE accelerates cranial nerve MR imaging for the diagnosis of facial neuritis: comparison of the diagnostic performance of post-contrast MPRAGE and CS-VIBE.

OBJECTIVE: We aimed to compare the diagnostic performance of post-contrast 3D compressed sensing volume-interpolated breath-hold examination (CS-VIBE) and 3D T1 magnetization-prepared rapid-acquisition gradient-echo (MPRAGE) in detecting facial neuritis. MATERIALS AND METHODS: Between February 2019 and September 2019, 60 patients (30 facial palsy patients and 30 controls) who underwent contrast-enhanced cranial nerve MRI with both conventional MPRAGE and CS-VIBE (scan time: 6 min 8 s vs. 2 min 48 s) were included in this retrospective study. All images were independently reviewed by three radiologists for the presence of facial neuritis. In patients with facial palsy, signal-to-noise ratio (SNR) of the pons, enhancement degree and contrast-to-noise ratio (CNRnerve-CSF) of the facial nerve were measured. The overall image quality, artifacts, and facial nerve discrimination were analyzed. The sensitivity and specificity of both sequences were calculated with the clinical diagnosis as a reference. RESULTS: CS-VIBE had comparable performance in the detection of facial neuritis to that of MPRAGE (sensitivity and specificity, 97.8% and 99.4% vs. 100.0% and 99.4% in pooled analysis; 97.8% and 98.9% vs. 100.0% and 98.9% in patents with facial palsy, p value > 0.05 for all). CS-VIBE showed significantly lower SNR (p value < 0.001 for all), but significantly higher CNRnerve-CSF (p value < 0.05 for all) than MPRAGE. CS-VIBE also performed better in the overall image quality, artifacts, and facial nerve discrimination than MPRAGE (p value < 0.001 for all). CONCLUSION: CS-VIBE achieved comparable diagnostic performance for facial neuritis compared to the conventional MPRAGE, with the scan time being half of that of MPRAGE. KEY POINTS: • Post-contrast 3D CS-VIBE MRI is a reliable method for the diagnosis of facial neuritis. • CS-VIBE reduces the scan time of cranial nerve MRI by more than half compared to conventional T1-weighted image. • CS-VIBE had better performance in contrast-to-noise ratio and favorable image quality compared with conventional T1-weighted image.

Changes in respiratory diseases in South Korea during the COVID-19 pandemic: an interrupted time series study.

INTRODUCTION: In South Korea, non-pharmaceutical interventions such as mask-wearing, hand washing and social distancing were strictly implemented to prevent the spread of COVID-19 after a national crisis alert was raised to the highest level early in the pandemic (23 February 2020). We aimed to investigate changes in the occurrence of respiratory diseases at the national level after the COVID-19 outbreak. METHODS: The study period was from 1 January to 1 August 2019 (213 days) and from 1 January to 31 July 2020 (213 days). Based on the National Health Insurance Service data, we analysed changes in the numbers of patients treated for respiratory diseases. The changes in the numbers of individuals using public transportation and visiting the theatre were investigated to assess the effect of social distancing after the national crisis alert was raised. Differences in daily cumulative numbers (DDCNs) in 2020 were calculated as follows: (daily cumulative number in 2020)-(cumulative number for that day in 2019). A change over time in DDCNs of <0 was taken as indication that the numbers decreased from 2019 to 2020. Segmented regression analyses were performed using generalised least squares method to identify changes in trends of DDCNs of patients treated for respiratory diseases and individuals using public transportation and visiting the theatre. RESULTS: After the national crisis alert was raised to the highest level, DDCNs of patients treated for respiratory diseases, individuals using public transportation, and those visiting the theatre exhibited a significant daily decline by 53.18 per 10 000 inhabitants (95% CI -65.86 to -40.49), 48.19 per 1000 inhabitants (95% CI -62.05 to -34.32) and 25.30 per 5000 inhabitants (95% CI -36.30 to -14.30), respectively, compared with before the national crisis alert was raised. CONCLUSION: Non-pharmaceutical interventions to prevent the spread of COVID-19 significantly reduce the incidence of respiratory diseases.

Role of microRNA­375­3p­mediated regulation in tinnitus development.

Changes in the dorsal cochlear nucleus (DCN) following exposure to noise play an important role in the development of tinnitus. As the development of several diseases is known to be associated with microRNAs (miRNAs/miRs), the aim of the present study was to identify the miRNAs that may be implicated in pathogenic changes in the DCN, resulting in tinnitus. A previously developed tinnitus animal model was used for this study. The study consisted of four stages, including identification of candidate miRNAs involved in tinnitus development using miRNA microarray analysis, validation of miRNA expression using reverse transcription­quantitative PCR (RT­qPCR), evaluation of the effects of candidate miRNA overexpression on tinnitus development through injection of a candidate miRNA mimic or mimic negative control, and target prediction of candidate miRNAs using mRNA microarray analysis and western blotting. The miRNA microarray and RT­qPCR analyses revealed that miR­375­3p expression was significantly reduced in the tinnitus group compared with that in the non­tinnitus group. Additionally, miR­375­3p overexpression via injection of miR­375­3p mimic reduced the proportion of animals with persistent tinnitus. Based on mRNA microarray and western blot analyses, connective tissue growth factor (CTGF) was identified as a potential target for miR­375­3p. Thus, it was inferred that CTGF downregulation by miR­375­3p may weaken with the decrease in miRNA expression, and the increased pro­apoptotic activity of CTGF may result in more severe neuronal damage, contributing to tinnitus development. These findings are expected to contribute significantly to the development of a novel therapeutic approach to tinnitus, thereby bringing about a significant breakthrough in the treatment of this potentially debilitating condition.

Impact of air pollution on benign paroxysmal positional vertigo incidence: a retrospective study of the citizens of Seoul, South Korea.

Benign paroxysmal positional vertigo (BPPV) is among the most common inner ear diseases. Although BPPV is one of the most common causes of dizziness, its pathogenesis remains unknown. Air pollutants might reach the middle ear through the eustachian tube and be absorbed into the inner ear through the round window membrane, increasing the risk of BPPV. We investigated the relationship between air pollution and BPPV risk. Data were extracted from the Korean Health Insurance Review and Assessment Service database, which contains health claims information of the entire South Korean population. Variables of interest included the number of patients diagnosed with BPPV in Seoul, South Korea, patients' clinical and demographic characteristics, and osteopenia status. Seoul's daily air pollution indicators, including SO2, CO, O3, NO2, PM10, and PM2.5, were obtained from the Korea Environment Corporation website. Overdispersed Poisson regression analysis was performed. In the multivariable analysis, NO2 air concentration (ppb) was associated with increased incidence of BPPV. In analysis stratified by gender, levels of NO2 were associated with increased incidence of BPPV in both men and women. In the analysis stratified by age, NO2 air concentration was associated with increased incidence of BPPV among all adults over the age of 19 years. In the analysis stratified by osteopenia status, NO2 was associated with increased incidence of BPPV in patients with and without osteopenia. Air levels of NO2 were associated with increased incidence of BPPV in the present study. This finding contributes toward a better understanding of BPPV pathogenesis and improved prevention and management of this condition.

MicroRNAs Related to Cognitive Impairment After Hearing Loss.

OBJECTIVES: Our research group has previously demonstrated that hearing loss might be a risk factor for synaptic loss within the hippocampus and impairment of cognition using an animal model of Alzheimer disease. In this study, after inducing hearing loss in a rat model of Alzheimer disease, the associations of various microRNAs (miRNAs) with cognitive impairment were investigated. METHODS: Rats were divided randomly into two experimental groups: the control group, which underwent sham surgery and subthreshold amyloid-ß infusion and the deaf group, which underwent bilateral cochlear ablation and subthreshold amyloid-ß infusion. All rats completed several cognitive function assessments 11 weeks after surgery, including the object-in-place task (OPT), the novel object recognition task (NOR), the object location task (OLT), and the Y-maze test. After the rats completed these tests, hippocampus tissue samples were assessed using miRNA microarrays. Candidate miRNAs were selected based on the results and then validated with quantitative reverse transcriptionpolymerase chain reaction (qRT-PCR) analyses. RESULTS: The deaf group showed considerably lower scores on the OPT, OLT, and Y-maze test than the control group. The microarray analysis revealed that miR-29b-3p, -30e-5p, -153-3p, -376a-3p, -598-3p, -652-5p, and -873-3p were candidate miRNAs, and qRT-PCR showed significantly higher levels of miR-376a-3p and miR-598-3p in the deaf group. CONCLUSION: These results indicate that miR-376a-3p and miR-598-3p were related to cognitive impairment after hearing loss.

The effects of climate on the incidence of benign paroxysmal positional vertigo.

Benign paroxysmal positional vertigo (BPPV) is one of the most common vestibular disorders. An investigation into the factors related to BPPV could contribute to its prevention and appropriate management. We investigated the association between climatic factors and incidence of BPPV in this study. A total of 365 patients who were diagnosed with idiopathic BPPV in the emergency room of our hospital in 2015 were included. The number of patients diagnosed with BPPV per week was calculated (every week). Climatic factors, including daily average humidity, temperature, atmospheric pressure, cloud amount, sunshine amount, and daylight time, were documented daily. The weekly mean climatic value in each week was calculated. Simple correlation analysis and multivariate regression analyses were performed to identify climatic factors associated with the number of patients diagnosed with BPPV. Simple correlation analysis revealed a significant association between the humidity (r = 0.276, p = 0.048), temperature (r = 0.275, p = 0.049), and cloud amount (r = 0.293, p = 0.035) and the number of BPPV patients diagnosed per week. Multivariate regression analysis revealed that only the cloud amount was a statistically significant factor associated with the number of BPPV patients diagnosed every week. A significant positive association was discovered between the cloud amount and BPPV incidence. Cloud amount can therefore have an association with the incidence of BPPV.

Influence of Cochlear Dead Regions on Hearing Outcome in Sudden Sensorineural Hearing Loss.

OBJECTIVE: The aims of this multicenter study were to prospectively evaluate the prevalence of dead regions (DRs) in sudden sensorineural hearing loss (SSNHL) and compare the clinical characteristics and hearing outcomes of SSNHL according to the presence of DRs. STUDY DESIGN: Prospective study. SETTING: Multicenter study. PATIENTS AND METHODS: The threshold-equalizing noise (TEN) test was prospectively performed on a total of 130 patients diagnosed with SSNHL. All patients received systemic steroid therapy and/or intratympanic steroid injection within 1 month after onset. Pure-tone audiograms and the TEN test were conducted before and after steroid treatment. Age, sex, side of affected ear, recurrence, onset of symptoms, presence of dizziness, and comorbid diseases were also collected. The prevalence of DRs in SSNHL and clinical factors related to the DRs were assessed. Hearing outcomes for SSNHL according to DRs were evaluated in 68 patients who followed a pure-tone audiogram. RESULTS: The overall prevalence of one or more DRs in SSNHL evaluated using the TEN test was 20.8% (27/130 subjects) and the overall frequency-specific prevalence of DR was 6.7% (61/910 DRs). Although the DRs (+)and DR (-) groups had similar initial pure-tone thresholds, the DRs (+) group had significantly worse initial WRS compared to the DRs (-) group (p = 0.015). The presence of DRs was not associated with hearing recovery in a multivariate logistic regression model, but it was significantly associated with the degree of hearing gain in a multivariate linear regression model (p = 0.018). CONCLUSIONS: The presence of DRs can be considered one of the poor prognostic factors for SSNHL and the TEN test may contribute to assess the prognosis of SSNHL in clinical settings.

Comparative Evaluation of the Effectiveness of Novel Hyaluronic Acid-Polynucleotide Complex Dermal Filler.

HA (Hyaluronic acid) filler, the most commonly used dermal filler, causes several side effects. HA-PN (Hyaluronic acid-Polynucleotide), a new composite filler, has excellent biocompatibility and induces tissue regeneration. In this study, we compare the efficacies and safety profiles of these fillers. The characteristics of HA and HA-PN fillers were compared using scanning electron microscopy and rheometry. No morphological difference was noted between the fillers. However, the latter had higher viscosity and elasticity values. The HA-PN filler induced higher cell migration than the HA filler in a wound healing assay. It was also found to stimulate better collagen synthesis in human and mouse fibroblasts. The HA and HA-PN fillers were injected into SKH1 hairless mice to determine changes in their volume for up to 24 weeks. Increased cell migration and collagen synthesis were observed in mice injected with the HA-PN complex filler. Although the safety and durability of the HA and HA-PN fillers were similar, the latter induced a lower transient receptor potential vanilloid 4 expression and caused less stimulation upon injection. In conclusion, HA-PN complex fillers can stimulate fibroblast growth and facilitate volume growth and skin regeneration.

Can Osteopenia Induce Residual Dizziness After Treatment of Benign Paroxysmal Positional Vertigo?

OBJECTIVE: This study aimed to determine whether there is an association between osteopenia and residual dizziness after successful treatment of benign paroxysmal positional vertigo (BPPV). METHODS: In all, 62 patients with canalolithiasis-type BPPV were included in the study. Patients were divided into two groups according to the presence of residual dizziness after resolution of BPPV. Univariate and multivariate analyses were performed to determine the factors associated with residual dizziness. Patients were analyzed based on age, sex, affected semicircular canal, affected side, BPPV duration, and presence of hypertension, diabetes mellitus, hyperlipidemia, and osteopenia. RESULTS: In univariate analysis, BPPV duration and osteopenia showed a relatively significant association (p < 0.20) with the development of residual dizziness. On subsequent multivariate analysis using these factors, osteopenia remained a statistically significant factor in association with residual dizziness (p = 0.012, odds ratio, 9.916). CONCLUSION: Osteopenia is associated with the development of residual dizziness. BPPV patients with osteopenia more frequently suffer from residual dizziness after successful treatment of BPPV than those without osteopenia.

Protective effects of human umbilical cord blood­derived mesenchymal stem cells against dexamethasone­induced apoptotic cell death in hair follicles.

Alopecia is a common and distressing condition, and developing new therapeutic agents to prevent hair loss is important. Human umbilical cord blood­derived mesenchymal stem cells (hUCB­MSCs) have been studied intensively in regenerative medicine. However, the therapeutic potential of these cells against hair loss and hair organ damage remains unclear, and the effects of hUCB­MSC transplantation on hair loss require evaluation. The current study aimed to investigate the effects of hUCB­MSCs on hair regression in vivo and restoration of anagen conduction on hair growth in vitro. The effects of hUCB­MSCs were explored in mouse catagen induction models using a topical treatment of 0.1% dexamethasone to induce hair regression. Dexamethasone was also used to simulate a stress environment in vitro. The results demonstrated that hUCB­MSCs significantly prevented hair regression induced by dexamethasone topical stimulation in vivo. Additionally, hUCB­MSCs significantly increased the proliferation of human dermal papilla cells (hDPCs) and HaCaT cells, which are key constituent cells of the hair follicle. Stimulation of vascular endothelial growth factor secretion and decreased expression of DKK­1 by hUCB­MSCs were also observed in hDPCs. Restoration of cell viability by hUCB­MSCs suggested that these cells exerted a protective effect on glucocorticoid stress­associated hair loss. In addition, anti­apoptotic effects and regulation of the autophagic flux recovery were observed in HaCaT cells. The results of the present study indicated that hUCB­MSCs may have the capacity to protect hair follicular dermal papilla cells and keratinocytes, thus preventing hair loss. Additionally, the protective effects of hUCB­MSCs may be resistant to dysregulation of autophagy under harmful stress.

Dysphagia Induced by Nasal Septal Chondroma: A Case Report.

Chondromas rarely occur in the nasal area and are usually found in the metaphyseal area of the phalanges and metacarpals of the hands, as well as the pelvis, sternum and scapula. The authors present an unusual case of dysphagia induced by histologically confirmed chondroma arising from the nasal septum. Treatment is to completely remove the mass with adequate margins of normal tissues to prevent recurrence and malignancy. Intranasal endoscopic removal of tumor with an adequate margin of normal tissue. After one year of treatment, there was no evidence of recurrence. We present a case of nasal septal chondroma in 18-year-old male. Keywords: chondroma; dysphagia; septum.

Axonal sprouting in the dorsal cochlear nucleus affects gap­prepulse inhibition following noise exposure.

One of the primary theories of the pathogenesis of tinnitus involves maladaptive auditory­somatosensory plasticity in the dorsal cochlear nucleus (DCN), which is assumed to be due to axonal sprouting. Although a disrupted balance between auditory and somatosensory inputs may occur following hearing damage and may induce tinnitus, examination of this phenomenon employed a model of hearing damage that does not account for the causal relationship between these changes and tinnitus. The present study aimed to investigate changes in auditory­somatosensory innervation and the role that axonal sprouting serves in this process by comparing results between animals with and without tinnitus. Rats were exposed to a noise­inducing temporary threshold shift and were subsequently divided into tinnitus and non­tinnitus groups based on the results of gap prepulse inhibition of the acoustic startle reflex. DCNs were collected from rats divided into three sub­groups according to the number of weeks (1, 2 or 3) following noise exposure, and the protein levels of vesicular glutamate transporter 1 (VGLUT1), which is associated with auditory input to the DCN, and VGLUT2, which is in turn primarily associated with somatosensory inputs, were assessed. In addition, factors related to axonal sprouting, including growth­associated protein 43 (GAP43), postsynaptic density protein 95, synaptophysin, α­thalassemia/mental retardation syndrome X­linked homolog (ATRX), growth differentiation factor 10 (GDF10), and leucine­rich repeat and immunoglobulin domain­containing 1, were measured by western blot analyses. Compared to the non­tinnitus group, the tinnitus group exhibited a significant decrease in VGLUT1 at 1 week and a significant increase in VGLUT2 at 3 weeks post­exposure. In addition, rats in the tinnitus group exhibited significant increases in GAP43 and GDF10 protein expression levels in their DCN at 3 weeks following noise exposure. Results from the present study provided further evidence that changes in the neural input distribution to the DCN may cause tinnitus and that axonal sprouting underlies these alterations.

Transplantation of autologous perichondrium with amniotic membrane for progressive scleral necrosis.

PURPOSE: Scleral necrosis with severe ischemia is refractory to conventional treatment because of avascular progressive necrosis. We assessed the therapeutic efficacy and safety of autologous perichondrium transplantation in patients with progressive scleral necrosis (PSN) and analyzed the clinical effects. METHODS: This study was a prospective, interventional, and noncomparative case series. Reconstructive surgery using autologous perichondrium and amniotic membrane (AM) was performed in patients with PSN who showed progressive ischemic scleral melting with impending perforation state and/or broad avascular area larger than 10 mm in diameter. The primary outcome was restoration of scleral integrity with healthy vascularized epithelium over the graft at six months after surgery. The secondary outcome was complication rate associated with autologous perichondrium graft use. RESULTS: Eighteen eyes of 14 patients underwent reconstructive surgery using autologous perichondrium patch and AM grafts. Observations indicated the graft provided the eyeball with successful structural integrity in 17 out of the 18 cases (94.4%) at six months after surgery. One eye showed a small scleral defect due to wound dehiscence at four month after the surgery. Additional surgery using perichondrium and AM stabilized the eye. The scleral necrosis healed completely after perichondrium and AM transplantation, even in cases with full-thickness scleral defect. The scleral integrity was maintained until the last follow-up session. There were no serious complications of endophthalmitis or graft infection. CONCLUSIONS: Reconstructive surgery using autologous perichondrium and AM is an effective method for restoration of scleral integrity and vascularization of the episclera and conjunctiva in eyes with PSN. Therefore, autologous perichondrium can be considered as an appropriate new biologic tissue for PSN.