Musashi-1 is the candidate of the regulator of hair cell progenitors during inner ear regeneration.

Background: Hair cell loss in the cochlea is caused by ototoxic drugs, aging, and environmental stresses and could potentially lead to devastating pathophysiological effects. In adult mammals, hair cell loss is irreversible and may result in hearing and balance deficits. In contrast, nonmammalian vertebrates, including birds, can regenerate hair cells through differentiation of supporting cells and restore inner ear function, suggesting that hair cell progenitors are present in the population of supporting cells.

Cholesterol influences potassium currents in inner hair cells isolated from guinea pig cochlea.

Objective: There is a correlation between serum hyperlipidemia and hearing loss. Cholesterol is an integral component of the cell membrane and regulates the activity of ion channels in the lipid bilayer. The aim of this study was to investigate the effects of cholesterol on the potassium currents in IHCs by using the cholesterol-depleting drug, MβCD, and water-soluble cholesterol.

Nitric oxide influences potassium currents in inner hair cells isolated from guinea-pig cochlea.

Objective: Nitric oxide (NO) is a diffusible second messenger, which regulates neurotransmission, serving as the principal endothelium-derived relaxing factor. NO also acts as an ion channel modulator. Nitric oxide synthase (NOS) has been identified in the inner ear, although its physiological role remains unclear.

Asymptomatic fibrous dysplasia of the temporal bone.

Introduction: Fibrous dysplasia is a bone disorder of unknown origin in which normal bone is replaced with fibrotic tissue and disorganised bone trabeculae. The temporal bone is rarely affected. Because of the slowly progressive course of the disease, many mild cases may never be recognised and are found incidentally.

Massively parallel DNA sequencing facilitates diagnosis of patients with Usher syndrome type 1.

Usher syndrome is an autosomal recessive disorder manifesting hearing loss, retinitis pigmentosa and vestibular dysfunction, and having three clinical subtypes. Usher syndrome type 1 is the most severe subtype due to its profound hearing loss, lack of vestibular responses, and retinitis pigmentosa that appears in prepuberty. Six of the corresponding genes have been identified, making early diagnosis through DNA testing possible, with many immediate and several long-term advantages for patients and their families.

Membranous band between the tympanic membrane and the external auditory canal.

Two cases of a membranous band between the tympanic membrane and the external auditory canal are presented. These characteristic structures are rare, but observed in several first branchial cleft anomalies. Neither patient presented with an infection.

The effect of pressure on potassium currents in the inner hair cells isolated from guinea-pig cochlea.

An increase in hydrostatic pressure in the endolymphatic system causes hydrops-related inner ear diseases such as Meniere's disease or low tone sensorineural hearing loss. In the present study, we investigated the effects of pressure exerted on potassium currents in acutely isolated inner hair cells of the guinea-pig cochlea using whole-cell voltage-clamp techniques. By applying negative or positive pressure via the patch pipette using a syringe, intracellular hydropressure was changed between -40 cm H2O to +20 cm H2O.

Temperature enhances activation and inactivation kinetics of potassium currents in inner hair cells isolated from Guinea-pig cochlea.

Objectives: Until recently, most patch-clamp recordings in inner hair cells (IHCs) have been performed at room temperature. The results acquired at room temperature should be corrected if they are to be related to in vivo findings. However, the temperature dependency to ion channels in IHCs is unknown.

[Problem and assignment for distinguishing the Usher syndrome type].

Usher syndrome is an autosomal-recessive disorder that causes bilateral sensorineural hearing loss, retinitis pigmentosa (RP), and occasionally vestibular dysfunction. Usher syndrome types 1, 2, and 3 can be distinguished by differences in audiovestibular features. The objectives of this retrospective study were to evaluate 26 patients with Usher syndrome clinically.

[Efficacy of levofloxacin 500 mg for middle ear diseases].

We examined the cases that prescribed levofloxacin (LVFX) 500mg for middle ear diseases in our hospital. LVFX 500mg was prescribed in 18 cases (7 male, 11 female, 24-81 years old). LVFX was mainly used for the following clinical conditions, 1) otitis media with granulation proliferation: 3 cases, 2) infection to an artificial materials : 5 cases, 3) treatment for or prevention against the inflammation of the inner ear: 4 cases.

No evidence for an association between persistent measles virus infection and otosclerosis among patients with otosclerosis in Japan.

Otosclerosis, which is characterized by disordered bone remodeling, occurs exclusively in the human temporal bone. The etiology of the disease is unknown, but a popular hypothesis is that it is caused by persistent measles virus (MV) infection. Paramyxovirus-like filamentous structures were found in otosclerotic lesions of stapes footplates from patients with otosclerosis.

Effect of salicylate on potassium currents in inner hair cells isolated from guinea-pig cochlea.

Although salicylate is one of the most widely used nonsteroidal anti-inflammatory drugs, it causes moderate hearing loss and tinnitus at high-dose levels. In the present study, salicylate effects on the K currents in inner hair cells were examined. Salicylate reversibly reduced the outward K currents (I(K,f)), but did not affect the inward current (I(K,n)).

Partial requirement of endothelin receptor B in spiral ganglion neurons for postnatal development of hearing.

Impairments of endothelin receptor B (Ednrb/EDNRB) cause the development of Waardenburg-Shah syndrome with congenital hearing loss, hypopigmentation, and megacolon disease in mice and humans. Hearing loss in Waardenburg-Shah syndrome has been thought to be caused by an Ednrb-mediated congenital defect of melanocytes in the stria vascularis (SV) of inner ears. Here we show that Ednrb expressed in spiral ganglion neurons (SGNs) in inner ears is required for postnatal development of hearing in mice.

Effect of hydrogen peroxide on potassium currents in inner hair cells isolated from guinea pig cochlea.

Hydrogen peroxide (H₂O₂) is a ubiquitous reactive oxygen species that can induce several inner ear disorders. In this study, we recorded the potassium (K) currents in acutely isolated inner hair cells of guinea pig cochlea, and investigated the effects of H₂O₂. We also observed the morphological changes in inner hair cells induced by H₂O₂.

Property of I(K,)(n) in inner hair cells isolated from guinea-pig cochlea.

One of the potassium currents, I(K,)(n), is already activated at the resting potential of the cell and thus determines the membrane potential. KCNQ4 channel has been identified as the molecular correlate of I(K,)(n). In the present study, we measured I(K,)(n) in acutely isolated IHCs of guinea-pig cochlea using the whole-cell voltage-clamp techniques, and investigated the properties of the currents.

Mice lacking ganglioside GM3 synthase exhibit complete hearing loss due to selective degeneration of the organ of Corti.

The ganglioside GM3 synthase (SAT-I), encoded by a single-copy gene, is a primary glycosyltransferase for the synthesis of complex gangliosides. In SAT-I null mice, hearing ability, assessed by brainstem auditory-evoked potentials (BAEP), was impaired at the onset of hearing and had been completely lost by 17 days after birth (P17), showing a deformity in hair cells in the organ of Corti. By 2 months of age, the organ of Corti had selectively and completely disappeared without effect on balance or motor function or in the histology of vestibule.

Dihydrostreptomycin goes through the mechano-electric transduction channel in chick cochlear hair cells.

Objective: This study evaluated the ability of dihydrostreptomycin (DHSM) to go through the mechano-electric transduction (MET) channels in hair cells under physiological conditions.

Materials And Methods: Tall hair cells were isolated from the chick basilar membrane (cochlea). Mechanical stimulation was applied by a glass rod attached to a piezoelectric bimorph, and MET currents were recorded with a whole-cell patch technique.

Nystagmus using video-oculography in psychiatric patients.

To evaluate whether nystagmus has clinical significance in psychiatric patients who have functional and/or organic brain dysfunction. We performed gaze, positional and positioning nystagmus tests on 227 patients with psychiatric diseases (144 men, 83 women, with an average age +/- SD of 62.5 +/- 14.

Inactivating potassium currents in apical and basal turn inner hair cells from guinea-pig cochlea.

Tetraethylammonium (TEA)-sensitive potassium currents in the cochlear inner hair cells (IHCs) possess the kinetics of fast inactivation. IHCs of guinea-pigs were separately isolated from the apical and basal turns and the tonotopic gradient of inactivation kinetics was investigated. TEA-sensitive potassium currents showed voltage-dependent time constant of the inactivation phase both in apical and basal IHCs, however, the degree of inactivation (compared to the ratio between the steady-state current and initial peak current) was voltage-independent.

Salicylate-induced morphological changes of isolated inner hair cells and outer hair cells from guinea-pig cochlea.

Objectives: The aim of this study is to investigate the salicylate-induced morphological changes of cochlear inner hair cells (IHCs) and outer hair cells (OHCs).

Methods: IHCs and OHCs were acutely isolated from the guinea-pig cochlea. Cells were observed under the inverted microscope and 10mmol/L sodium salicylate solutions or 0.

Histochemical localization of the extracellular matrix components in the annular ligament of rat stapediovestibular joint with special reference to fibrillin, 36-kDa microfibril-associated glycoprotein (MAGP-36), and hyaluronic acid.

The annular ligament across the stapediovestibular joint connects the stapes footplate and the vestibular window and plays an important role in the sound conductive system of the ear. In this study, we investigated the distribution of extracellular matrix components in the ligament by histochemical methods at light and electron microscopic levels. As results, light microscopic immunohistochemistry of fibrillin and 36-kDa microfibril-associated glycoprotein (MAGP-36) showed intense immunoreactivities in the annular ligament between the stapes footplate and vestibular window.

Calcium action on the membrane currents possessing the properties of mechano-electric transducer currents in inner hair cells of the Guinea-pig cochlea.

In free-standing hair bundle, depolarization to +80 mV evoked a stable outward current and repolarization to -80 mV evoked a transient inward current attributable to the opening of mechano-electric transducer channels. The study investigated the Ca2+ dependence of this transducer-like membrane current in isolated inner hair cells of guinea-pig cochlea. The amplitude of outward currents increased and the rate of inward current decay, corresponding to adaptation kinetics, decreasing as the extracellular Ca2+ concentrations lessened, whereas the amplitude of outward current decreased and an adaptation accelerated as the extracellular Ca2+ elevated.

Three-dimensional regular arrangement of the annular ligament of the rat stapediovestibular joint.

The stapes footplate articulates with the vestibular window through the annular ligament. This articulation is known as the stapediovestibular joint (SVJ). We investigated the ultrastructure of adult rat SVJ and report here on the characteristic ultrastructure of the corresponding annular ligament.

Dissociation enzyme effects on the potassium currents of inner hair cells isolated from guinea-pig cochlea.

Tetraethylammonium (TEA)-sensitive potassium currents in the cochlear inner hair cells (IHCs) possess the kinetics of fast inactivation. Some enzymes using for IHCs dissociation affect these inactivation kinetics. IHCs were dissociated from guinea-pig cochlea by 1 mg/ml trypsin or 0.

Inactivating and non-inactivating potassium currents in isolated inner hair cells from guinea pig cochlea.

Using conventional whole-cell voltage-clamp recordings, we examined the 4-aminopyridine (4-AP)- and tetraethylammonium (TEA)-sensitive K(+) currents in the cochlear inner hair cells (IHCs) of guinea pigs. 4-AP-sensitive currents were activated slowly and sustained the same current level, whereas TEA-sensitive currents were activated rapidly, followed by inactivation. The inactivation time course of TEA-sensitive currents was voltage-dependent, becoming faster at more depolarized levels.