ABSTRACT
One of the bacterial infections caused by tympanic membrane perforation is otitis media (OM). Middle ear inflammation causes continuous pain and can be accompanied by aftereffects such as facial nerve paralysis if repeated chronically. Therefore, it is necessary to develop an artificial tympanic membrane (TM) that can effectively regenerate the eardrum due to the easy implantation and removal of OM inflammation. In this study, we synthesized hydrogel by mixing gelatin and polyacrylamide. Cefuroxime sodium salt was then incorporated into this hydrogel to both regenerate the TM and treat OM. Cytotoxicity experiments confirmed the biocompatibility of hydrogels equipped with antibiotics, and we conducted drug release and antibacterial experiments to examine continuous drug release. Through experiments, we have verified the excellent biocompatibility, drug release ability, and antibacterial effectiveness of hydrogel. It holds the potential to serve as an effective strategy for treating OM and regenerating TM as a drug delivery substance.
ABSTRACT
OBJECTIVES: The distribution and extent of excitable spiral ganglion neurons (SGNs) have been investigated using the electrically evoked auditory brainstem response (EABR) during preoperative and perioperative periods. In this study, we investigated the EABR with extracochlear stimulation (eEABR) as a preoperative test to estimate these factors. METHODS: Sixteen male Sprague-Dawley rats were used in this study. Experiments were conducted in nine rats with normal hearing and seven rats that were partially deafened with ouabain treatment. Each experiment involved the following steps: extracochlear stimulating electrode placement at three different sites along the axis of the cochlea and eEABR recordings; cochleostomy and four-channel intracochlear array implantation, followed by EABR recordings with various electrode pair combinations; and after electrophysiological measurements, harvest of the cochleae for histopathological evaluation. The slope characteristics of the amplitude growth function measured from eEABR and EABR, frequency-specific auditory thresholds, and the density of SGNs were compared. RESULTS: Similar trends were observed in slope changes on different sites of stimulation with both types of stimulation in normal-hearing animals-specifically, a monotonically increasing slope with increasing distance between bipolar pairs. In addition, eEABR slopes showed significant correlations with EABR slopes when the expected cochlear regions of stimulation were similar in normal-hearing animals. In partially deaf animals, the auditory thresholds at several frequencies had a significant correlation with the eEABR slopes of each extracochlear electrode at the apical, middle, and basal cochlear positions. This indicated that increasing the regions of cochlear stimulation had a differential impact on eEABR slopes, depending on the neural conditions. CONCLUSION: Our results indicated that eEABR slopes showed significant spatial correlations with the functionality of the auditory nerve. Therefore, eEABR tests at various cochlear positions might be used for estimating the extent of excitable SGNs in cochlear implant candidates prior to implantation.
ABSTRACT
Stapedotomy or stapedectomy operations are often performed to treat otosclerosis. During the operation, the space created by bone removal is usually filled with a closing material such as fat or fascia. In this study, the effect of the Young's modulus of the closing material on the hearing level was investigated through the 3D finite element model of a human head including auditory periphery. The Young's moduli of the closing material used to implement stapedotomy and stapedectomy conditions in the model were varied from 1 kPa to 24 MPa. The results showed that the hearing level improved when the closing material was more compliant after stapedotomy. Therefore, when the stapedotomy was performed using fat whose Young's modulus is lowest among the potential closing materials, the hearing level recovered the best among all simulated cases. On the other hand, in stapedectomy, the Young's modulus did not have the linear relationship between the hearing level and the compliance of the closing material. Hence, the Young's modulus causing the best hearing rehabilitation in stapedectomy was found not at the end of the investigated range of Young's modulus but somewhere in the middle of the given range.
ABSTRACT
Current biometrics rely on images obtained from the structural information of physiological characteristics, which is inherently a fatal problem of being vulnerable to spoofing. Here, we studied personal identification using the frequency-domain information based on human body vibration. We developed a bioacoustic frequency spectroscopy system and applied it to the fingers to obtain information on the anatomy, biomechanics, and biomaterial properties of the tissues. As a result, modulated microvibrations propagated through our body could capture a unique spectral trait of a person and the biomechanical transfer characteristics persisted for two months and resulted in 97.16% accuracy of identity authentication in 41 subjects. Ultimately, our method not only eliminates the practical means of creating fake copies of the relevant characteristics but also provides reliable features.
Subject(s)
Acoustics , Biometric Identification/methods , Spectrum Analysis/methods , Algorithms , Computer Security , Fingers/physiology , Humans , Machine Learning , Sound SpectrographyABSTRACT
OBJECTIVE: The psoas muscle (PS), 1 of the paravertebral core muscles, is associated with sarcopenia. It also has clinical relevance in lateral-access spinal surgery (LASS) as a determinant structure affecting the operative window. We aimed to identify age-related patterns of PS degeneration, and we propose that our results be used to evaluate the operative window in LASS. METHODS: We included 164 participants with back pain, no leg symptoms or claudication, and normal lumbar lordosis and sagittal balance. We evaluated the cross-sectional morphology of the PS on magnetic resonance imaging, specifically assessing the anterior to posterior (AP)/medial to lateral (ML) ratio and the cross-sectional area (CSA). We assessed the locational relationship of the PS and the intervertebral disc using the anterior margin gap (AMG; the distance between the anterior margins of the PS and the intervertebral disc) and the center gap, and compared all measurements by surgical level, sex, and age group. RESULTS: At the L2-3 to L4-5 levels, the PS showed a decreased AP/ML ratio, increased CSA, ventral retraction of the anterior margin without center shift, and decreased operative window length. The degeneration patterns were decreased ML width and CSA and dorsal retraction of the anterior margin. Youth, male sex, and lower lumbar level were associated with higher AMGs, indicating an increased need for the transpsoas approach in LASS. CONCLUSIONS: In patients without sagittal imbalance, the PS showed significant imaging characteristics. Our detailed data may aid the identification of degeneration patterns and specific preoperative planning regarding the operative window for LASS.