Intratympanic injection for treatment of inner ear diseases

Intratympanic injection has emerged as a novel approach to bypass the blood-labyrinth barrier and effectively deliver drugs into the inner ear. This technique is used for treatment of various inner ear diseases and overcomes the limitations of systemic drug therapy. In this paper, we provide an overview of the application of intratympanic injection using steroids and gentamicin and highlight the major diseases and summarize the reported efficacy of this approach.Current Concepts: Intratympanic steroid injections have been used for treatment of various inner ear diseases, including sudden sensorineural hearing loss, Ménière disease, and tinnitus. Therapeutic effects of steroids include reducing inflammation, modulating the immune response, improving cochlear blood flow, and maintaining ion homeostasis. Intratympanic gentamicin injections are primarily used to minimize hearing loss and control vertigo symptoms in patients with Ménière disease. Gentamicin selectively injures vestibular hair cells with minimal ototoxicity compared with other aminoglycoside antibiotics.Discussion and Conclusion: Intratympanic injections offer several advantages, including targeted drug delivery, minimal systemic adverse effects, and rapid action. Reportedly, intratympanic steroid injections used as primary or salvage treatment are associated with positive outcomes in patients with sudden sensorineural hearing loss. Ménière disease also shows positive outcomes following intratympanic steroid and gentamicin injections. However, studies have reported conflicting results, and further research is required to standardize dosing and administration protocols. Intratympanic injections are a promising therapeutic option, and ongoing research is essential to optimize their efficacy and safety.

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.

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-β infusion and the deaf group, which underwent bilateral cochlear ablation and subthreshold amyloid-β 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.

Novel Tie Method for the Fixation of a Brain Infusion Cannula in a Murine Model / 대한이비인후과학회지

Although brain infusion cannula is a good method to deliver compounds directly into the brain, fixation of the brain infusion cannula is essential for successful delivery. Dental cements and adhesive gel are the commonly used materials for fixation of the infusion cannula. However, these materials take time to harden and occasionally, fixation may fail. Therefore, we developed a novel method to fix the brain infusion cannula. Brain infusion cannulas were implanted into seven Wistar rats using the novel tie method. One, three, and seven days after the surgery, displacement of the brain infusion cannula and cerebrospinal fluid (CSF) leakage were evaluated in all the rats. None of the animals showed displacement of the brain infusion cannula or leakage of CSF at any point of time. In this study, we showed the successful results of the novel tie method for fixation of the brain infusion cannula, which needs no additional materials. It only requires a thread which is used for skin sutures.

Effect of Temporal Bone Fracture on the Prognosis of Benign Paroxysmal Positional Vertigo / 대한이비인후과학회지

Background and Objectives@#This study aimed to investigate whether benign paroxysmal positional vertigo (BPPV) accompanied by temporal bone fracture would be more resistant to canalith repositioning procedures (CRPs) than idiopathic BPPV.Subjects and Method Seventy-eight patients with BPPV were included in this study. Among them, 13 patients had temporal bone fractures and 65 had no temporal bone fractures. To identify the factors related to the number of CRPs performed until the remission of BPPV, sex, age, the presence of temporal bone fracture, hypertension, diabetes, dyslipidemia or osteopenia, BPPV affected side, and the type of affected semicircular canal were analyzed using the univariable regression analysis. Thereafter, the multivariable regression analysis was performed using only the variables that had a p-value of 0.2 or less in the univariable analysis. @*Results@#In the univariable analysis, temporal bone fracture, diabetes mellitus, and BPPV side showed relatively significant association with the number of CRPs (p<0.2). In the multivariable analysis, only temporal bone fracture showed a significant association with the number of CRPs (p=0.043, β=0.532, 95% CI: 0.017-1.046). @*Conclusion@#The major finding of this study is that BPPV, accompanied by temporal bone fracture, precipitated more resistance to CRPs than idiopathic BPPV did. Thus, patients with temporal bone fracture might need more intensive examination and treatment for BPPV than those without temporal bone fracture.

Residual Dizziness after Benign Paroxysmal Positional Vertigo / 대한이비인후과학회지

Benign paroxysmal positional vertigo (BPPV) is one of the most common diseases that cause dizziness. It can be resolved relatively easily using canalith-repositioning maneuvers. However, some patients suffer from dizziness even after successful canalith-repositioning. This is an atypical dizziness felt in the absence of typical nystagmus after resolution of BPPV and named residual dizziness. Otolithic organ disorder, anxiety and persistence of debris in the canal have been reported to be associated with residual dizziness. Although 31-61% of BPPV patients suffer from residual dizziness, residual dizziness has not yet been clearly known not only the treatment but also the pathophysiology. This article investigate the factors associated with residual dizziness and treatment and prediction methods for residual dizziness.