Keiko Hirose

Learn More
To assess the dynamics of noise-induced tissue injury and repair, groups of CBA/CaJ mice were exposed to an octave-band noise for 2 hours at levels of 94, 100, 106, 112, or 116 dB SPL and evaluated at survival times of 0, 12, 24 hours or 1, 2, or 8 weeks. Functional change, assessed via auditory brainstem response (ABR), ranged from a reversible threshold(More)
Kinesin motor proteins release nucleotide upon interaction with microtubules (MTs), then bind and hydrolyze ATP to move along the MT. Although crystal structures of kinesin motors bound to nucleotides have been solved, nucleotide-free structures have not. Here, using cryomicroscopy and three-dimensional (3D) reconstruction, we report the structure of MTs(More)
Acoustic injury results in destruction of hair cells and numerous nonsensory cells of the cochlea. How these injured structures undergo repair is not well understood. This study was designed to examine the cochlea for the presence of mononuclear phagocytes after tissue injury caused by noise damage. We used octave band noise (8--16 kHz) at three levels(More)
PURPOSE OF REVIEW To summarize mechanisms of ototoxicity associated with aminoglycoside antibiotics and discuss possible protective strategies. RECENT FINDINGS Studies in the past 15 years have demonstrated that aminoglycoside ototoxicity is mediated by an apoptotic form of cell death which employs caspase-dependent pathways. Reactive oxygen species have(More)
Noise exposure damages the stria and spiral ligament and may contribute to noise-induced threshold shift by altering the endocochlear potential (EP). The aim of this study was to correlate lateral wall histopathology with changes in EP and ABR thresholds. CBA/CaJ mice were exposed to octave band (8–16 kHz) noise for 2 h at intensities ranging from 94 to 116(More)
The function of the orphan glutamate receptor delta subunits (GluRdelta1 and GluRdelta2) remains unclear. GluRdelta2 is expressed exclusively in the Purkinje cells of the cerebellum, and GluRdelta1 is prominently expressed in inner ear hair cells and neurons of the hippocampus. We found that mice lacking the GluRdelta1 protein displayed significant cochlear(More)
Reactive oxygen species have been invoked as a causative agent of cell death in many different developmental and pathological states. The presence of free radicals and their importance of hair cell death due to aminoglycosides is suggested by a number of studies that have demonstrated a protective effect of antioxidants. By using dichlorofluorescin (DCFH) a(More)
OBJECTIVE We sought to reintroduce a historical procedure-intracapsular tonsillar reduction (partial tonsillectomy or tonsillotomy)-for tonsillar hypertrophy causing obstructive sleep disordered breathing (OSDB) in children, as well as to determine whether partial tonsillectomy, compared with conventional (total) tonsillectomy when performed by more than(More)
To determine the physiological functions of the mammalian double-stranded RNA-binding protein PACT, the single-copy mouse Pact gene was disrupted and expression of the protein was completely ablated. The most notable phenotypes of the Pact(-/-) mouse were reduced size and severe microtia. As a result of the congenital abnormality of both outer and middle(More)
Acoustic trauma was recently shown to induce an inflammatory response in the ear characterized by rapid entry of macrophages in the spiral ligament. The current study seeks to elucidate the mechanisms involved in summoning macrophages to the cochlear lateral wall and the role macrophages play in noise-induced injury or repair. CCL2 and its primary receptor,(More)