The spatiotemporal distribution of drugs in the inner ear cannot be precisely evaluated because of its small area and complex structure. In the present study, we used hyaluronic acid (HA)-dispersed luciferin to image transgenic mice and to determine the effect of HA on controlled drug delivery to the cochlea. GFAP-luc mice, which express luciferase in cochlear spiral ganglion cells, were subcut...

In inner ear development, phosphatase and tensin homolog (PTEN) is necessary for neuronal maintenance, such as neuronal survival and accurate nerve innervations of hair cells. We previously reported that Pten conditional knockout (cKO) mice exhibited disorganized fasciculus with neuronal apoptosis in spiral ganglion neurons (SGNs). To better understand the genes and signaling networks related t...

Given the frequent use of improvised explosive devices (IEDs) around the world, the study of traumatic blast injuries is of increasing interest. The ear is the most common organ affected by blast injury because it is the body's most sensitive pressure transducer. We fabricated a blast chamber to re-create blast profiles similar to that of IEDs and used it to develop a reproducible mouse model t...

Hearing function is known to be heritable, but few significant and reproducible associations of genetic variants have been identified to date in the adult population. In this study, genome-wide association results of hearing function from the G-EAR consortium and TwinsUK were used for meta-analysis. Hearing ability in eight population samples of Northern and Southern European ancestry (n = 4591...

the exposure to electromagnetic field emitted by mobile telephones is increasing rapidly worldwide that causes side effects, including thermal and non thermal side effects. ear proximity to electromagnetic source may lead to greater damage and side effects, including hearing loss. this study was performed to assess the chronic effect of exposure to electromagnetic field of mobile telephones on ...

introduction: to reduce incidence of residual cholesteatoma following ear surgery; and to reduce the need for second look “open” mastoidectomy using endoscopic mastoidotomy. ten-year retrospective chart review of 249 primary cholesteatoma cases (1994-2004) with a minimum follow-up of two years.  the first objective was to evaluate the effectiveness of otoendoscopy in reducing the incidence of “...

Auditory nerve fibers (ANFs) encode the synaptic input from the inner hair cells into afferent spiking information that is thereafter processed by the different nuclei in the auditory system. If the hair cells in the inner ear are degenerated and therefore not able to provide synaptic input to ANFs, cochlear implants (CIs) can be used to stimulate the ANFs (spiral ganglion cells) directly with ...

Glutamate is an important excitatory neurotransmitter in mammalian brains, but excessive amount of glutamate can cause "excitotoxicity" and lead to neuronal death. As bipolar neurons, spiral ganglion neurons (SGNs) function as a "bridge" in transmitting auditory information from the ear to the brain and can be damaged by excessive glutamate which results in sensorineural hearing loss. In this s...

Osteoprotegerin (OPG) is a key regulator of bone remodeling. Mutations and variations in the OPG gene cause many human diseases that are characterized by not only skeletal abnormalities but also poorly understood hearing loss: Paget's disease, osteoporosis, and celiac disease. To gain insight into the mechanisms of hearing loss in OPG deficiency, we studied OPG knockout (Opg(-/-)) mice. We show...

The mammalian cochlea is a highly complex structure which contains several cells, including sensory receptor or hair cells. The main function of the cochlear hair cells is to convert the mechanical vibrations of the sound into electrical signals, then these signals travel to the brain along the auditory nerve. Auditory hair cells in some amphibians, reptiles, fish, and birds can regenerate or r...