Aims: Methionine sulfoxide reductase B3 (MsrB3), which stereospecifically repairs methionine- R -sulfoxide, is an important Msr protein that is associated with auditory function in mammals. MsrB3 deficiency leads to profound congenital hearing loss due to the degeneration of stereociliary bundles and the apoptotic death of cochlear hair cells. In this study, we investigated a fundamental treatment strategy in an MsrB3 deficiency mouse model and confirmed the biological significance of MsrB3 in the inner ear using MsrB3 knockout ( MsrB3 ^−/− ) mice. Results: We delivered a recombinant adeno-associated virus encoding the MsrB3 gene directly into the otocyst at embryonic day 12.5 using a transuterine approach. We observed hearing recovery in the treated ears of MsrB3 ^−/− mice at postnatal day 28, and we confirmed MsrB3 mRNA and protein expression in cochlear extracts. Additionally, we demonstrated that the morphology of the stereociliary bundles in the rescued ears of MsrB3 ^−/− mice was similar to those in MsrB3 ^+/+ mice. Innovation: To our knowledge, this is the first study to demonstrate functional and morphological rescue of the hair cells of the inner ear in the MsrB3 deficiency mouse model of congenital genetic sensorineural hearing loss using an in utero , virus-mediated gene therapy approach. Conclusion: Our results provide insight into the role of MsrB3 in hearing function and bring us one step closer to hearing restoration as a fundamental therapy. Antioxid. Redox Signal. 24, 590–602.

We describe the design and development of a tri-coil bellows transducer (TCBT) for use in an implantable middle-ear hearing aid for round window (RW) drive. The TCBT provides easy implantation and a better frequency response than previous RW middle-ear transducers. It consisted of three cylindrical coils, a bonded magnet, and a tiny bellows with multiple corrugations. The simulation started with the calculation of the vibrational force required for the RW-drive transducer. Based on the anatomical structure of the RW niche and its volume, the designed TCBT was 1.75 mm in diameter and 2.3 mm long. To maximize the electromagnetic force of a TCBT installed within the limited volume of the RW niche, its structure was designed using an electromagnetic analysis based on finite-element analysis to determine the each length of the three cylindrical coils and the bonded magnet inside the TCBT. Additionally, the resonance frequency characteristics of the TCBT were determined using mechanical vibration analysis. A prototype TCBT was fabricated according to the simulation results, and an experiment to evaluate its vibrational characteristics was performed with the TCBT in an unloaded condition. Finally, the performance of the TCBT for use in RW-drive implantable middle-ear hearing aids was confirmed in experiments with cadaveric temporal bones.

Background: Recently, a capsule endoscope has been developed and many researchers have been trying to develop locomotive capsules. To develop locomotive capsules, the inner volume of the capsule has to be large enough to insert actuators, and the edge shape of the exterior capsule has to be suitable for locomotion. There are many locomotional methods, but an electrical stimulus method provides the appropriate power consumption, plus the shape of the capsule is the same as general telemetry capsules. In this paper, the optimal shape of the electrical stimulus capsule (ESC) was designed and implemented to provide the appropriate inner volume and moving speed of the capsule.Methods: A simple mathematical model was used to simulate various capsule shapes, and simple mathematical formulae were used to simulate the relationship between the shape of the edge of the capsule and the contraction force of the small intestine. The optimal edge shape of the capsule was decided based on the crossing point of the volume and moving speed. To verify the simulation, two capsules were implemented as the control and experimental groups.Results: From thein vitroexperiments, four fresh intestines were used to measure the moving speed of the capsules. The average speed of the proposed capsule was 0.125 ± 0.096 cm/s (20 V, 10 ms, 20 Hz), while the control group capsule was only 0.016 ± 0.33 cm/s (20 V, 10 ms, 20 Hz), and both groups showed a significant difference from the statistical analysis (p< 0.001, Mann–Whitney rank sum test).Conclusions: This paper presents a proposed design for the external shape of the ESC that could fill the need of researchers who want more inner volume and doctors who want to prevent the capsule from being stuck in the intestine. Copyright © 2009 John Wiley & Sons, Ltd.