Injectable Poloxamer Hydrogel Formulations for Intratympanic Delivery of Dexamethasone.

Background: In this study, we prepared and evaluated an injectable poloxamer (P407) hydrogel formulation for intratympanic (IT) delivery of dexamethasone (DEX).

Methods: DEX-loaded P407 hydrogels were characterized in terms of thermogelation, drug loading capacities, particle size, and drug release. The in vivo toxicity and drug absorption of the DEX-loaded P407 formulation after IT injection were evaluated using an animal model by performing histopathological analysis and drug concentration measurements.

Sex differences in hearing impairment due to diet-induced obesity in CBA/Ca mice.

Background: Obesity is an independent risk factor for hearing loss. Although attention has focused on major obesity comorbidities such as cardiovascular disease, stroke, and type 2 diabetes, the impact of obesity on sensorineural organs, including the auditory system, is unclear. Using a high-fat diet (HFD)-induced obese mouse model, we investigated the impact of diet-induced obesity on sexual dimorphism in metabolic alterations and hearing sensitivity.

Injectable glycol chitosan thermogel formulation for efficient inner ear drug delivery.

We prepared a new injectable thermogel to enhance the efficiency of inner ear delivery of dexamethasone (DEX). Hexanoyl glycol chitosan (HGC) was synthesized and evaluated as an amphiphilic thermogel (T ~ 32 °C) for use as a solubilizing agent as well as an injectable carrier for intratympanic delivery of the hydrophilic and hydrophobic forms of DEX. Various thermogel formulations with different drug types and concentrations were prepared, and their physicochemical and thermogelling properties were characterized by H NMR, ATR-FTIR, and rheometer.

Junctional Modulation of Round Window Membrane Enhances Dexamethasone Uptake into the Inner Ear and Recovery after NIHL.

Delivery of substances into the inner ear via local routes is increasingly being used in clinical treatment. Studies have focused on methods to increase permeability through the round window membrane (RWM) and enhance drug diffusion into the inner ear. However, the clinical applications of those methods have been unclear and few studies have investigated the efficacy of methods in an inner ear injury model.

Hearing Impairment in a Mouse Model of Diabetes Is Associated with Mitochondrial Dysfunction, Synaptopathy, and Activation of the Intrinsic Apoptosis Pathway.

Although previous studies continuously report an increased risk of hearing loss in diabetes patients, the impact of the disease on the inner ear remains unexplored. Herein, we examine the pathophysiology of diabetes-associated hearing impairment and cochlear synaptopathy in a mouse model of diabetes. Male B6.

Mitochondrial Damage and Necroptosis in Aging Cochlea.

Age-related hearing loss (ARHL) is an irreversible, progressive neurodegenerative disorder and is presently untreatable. Previous studies using animal models have suggested mitochondrial damage and programmed cell death to be involved with ARHL. Thus, we further investigated the pathophysiologic role of mitochondria and necroptosis in aged C57BL/6J male mice.

Acoustic Trauma Modulates Cochlear Blood Flow and Vasoactive Factors in a Rodent Model of Noise-Induced Hearing Loss.

Noise exposure affects the organ of Corti and the lateral wall of the cochlea, including the stria vascularis and spiral ligament. Although the inner ear vasculature and spiral ligament fibrocytes in the lateral wall consist of a significant proportion of cells in the cochlea, relatively little is known regarding their functional significance. In this study, 6-week-old male C57BL/6 mice were exposed to noise trauma to induce transient hearing threshold shift (TTS) or permanent hearing threshold shift (PTS).

Cochlear Glucocorticoid Receptor and Serum Corticosterone Expression in a Rodent Model of Noise-induced Hearing Loss: Comparison of Timing of Dexamethasone Administration.

Glucocorticoid (GC) is a steroid hormone secreted from the adrenal cortex in response to stress, which acts by binding to cytoplasmic glucocorticoid receptors (GRs). Dexamethasone (DEX) is a synthetic GC exhibiting immunosuppressive effects in both human and rodent models of hearing loss. While clinical evidence has shown the effectiveness of DEX for treatment of various inner ear diseases, its mechanisms of action and the optimal timing of treatment are not well understood.

Tinnitus in the side with better hearing.

Objectives: We aimed to confirm the characteristics of patients with tinnitus in the better-hearing side.

Materials And Methods: Among the 778 patients who visited the tinnitus clinic complaining of unilateral tinnitus at a local university hospital between March 2014 and December 2017, we recruited 62 patients who showed tinnitus in the better-hearing side on pure-tone audiometry. The mean hearing threshold was calculated using the arithmetic mean of the pure tone thresholds at 1, 2, 3, and 4 kHz.

Paper patching for patulous eustachian tube.

Background: Paper patching, a method that places cigarette paper over the most mobile quadrants of the tympanic membrane, is one of the treatment options for patulous eustachian tube (PET).

Aims/objectives: The objective of this study was to compare the outcomes of two different treatment strategies for PET.

Material And Methods: Twenty-three patients underwent paper patching of the tympanic membrane and 16 patients were treated with nasal saline irrigation with or without ipratropium bromide nasal spray.

Audiometric Profiles in Patients With Normal Hearing and Bilateral or Unilateral Tinnitus.

Hypothesis: Patients with subjective nonpulsatile tinnitus and a normal conventional audiogram have more objective audiologic evidence of hidden hearing loss and deafferentation-related pathology than patients without tinnitus.

Background: The aim of this study was to assess the epidemiologic characteristics and audiologic profiles, including auditory brainstem response (ABR), distortion product otoacoustic emission, and threshold-equalizing noise test results, in patients with tinnitus and a normal audiogram.

Methods: The test results for 20 patients complaining of nonpulsatile chronic tinnitus were compared with those of 91 subjects with normal hearing and no tinnitus.

Clinical Characteristics of Dizziness Associated with Acute Peripheral Facial Palsy.

Background And Objectives: We aimed to assess the clinical significance of dizziness associated with acute peripheral facial palsy (APFP).

Subjects And Methods: Medical records of patients who visited an otorhinolaryngology clinic at a university hospital and were admitted for treatment of APFP between 2014 and 2016 were thoroughly reviewed.

Results: In total, 15.

Susceptibility of Diabetic Mice to Noise Trauma.

Diabetes can lead to many end-organ complications. However, the association between diabetes and hearing loss is not well understood. Here, we investigated the effect of noise exposure on diabetic mice compared with wild-type mice.

Effects of dexamethasone on intracochlear inflammation and residual hearing after cochleostomy: A comparison of administration routes.

Preservation of residual hearing after cochlear implant is an important issue with regards to hearing performance. Various methods of steroid administration have been widely used in clinical practice to reduce inflammation and preserve residual hearing. Here we compare the effect of different routes of dexamethasone administration on intracochlear inflammation and residual hearing in guinea pig ears.

Characteristics of patients with acute peripheral facial palsy showing Varicella zoster virus DNA in saliva.

Infection caused by Varicella zoster virus (VZV) is a common etiology of acute peripheral facial palsy (APFP). We aimed to assess the clinical significance of detecting VZV DNA from the saliva of patients with APFP. Saliva collected from 36 patients with unilateral APFP at initial visit was analyzed to detect VZV DNA by polymerase chain reaction.

Phlorofucofuroeckol Improves Glutamate-Induced Neurotoxicity through Modulation of Oxidative Stress-Mediated Mitochondrial Dysfunction in PC12 Cells.

Stroke is a complex neurodegenerative disorder with a clinically high prevalence and mortality. Despite many efforts to protect against ischemic stroke, its incidence and related permanent disabilities continue to increase. In this study, we found that pretreatment with phlorofucofuroeckol (PFF), isolated from brown algae species, significantly increased cell viability in glutamate-stimulated PC12 cells.

Lateral geniculate body evoked potentials elicited by visual and electrical stimulation.

Purpose: Blind individuals who have photoreceptor loss are known to perceive phosphenes with electrical stimulation of their remaining retinal ganglion cells. We proposed that implantable lateral geniculate body (LGB) stimulus electrode arrays could be used to generate phosphene vision. We attempted to refine the basic reference of the electrical evoked potentials (EEPs) elicited by microelectrical stimulations of the optic nerve, optic tract and LGB of a domestic pig, and then compared it to visual evoked potentials (VEPs) elicited by short-flash stimuli.