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https://www.readbyqxmd.com/read/28431308/hyperexcitability-of-inferior-colliculus-and-acoustic-startle-reflex-with-age-related-hearing-loss
#1
Binbin Xiong, Ana'am Alkharabsheh, Senthilvelan Manohar, Guang-Di Chen, Ning Yu, Xiaoming Zhao, Richard Salvi, Wei Sun
Chronic tinnitus and hyperacusis often develop with age-related hearing loss presumably due to aberrant neural activity in the central auditory system (CAS) induced by cochlear pathologies. However, the full spectrum of physiological changes that occur in the CAS as a result age-related hearing loss are still poorly understood. To address this issue, neurophysiological measures were obtained from the cochlea and the inferior colliculus (IC) of 2, 6 and 12 month old C57BL/6J mice, a mouse model for early age-related hearing loss...
March 27, 2017: Hearing Research
https://www.readbyqxmd.com/read/28415260/enhanced-processing-in-arrays-of-optimally-tuned-nonlinear-biomimetic-sensors-a-coupling-mediated-ringelmann-effect-and-its-dynamical-mitigation
#2
Alexander P Nikitin, Adi R Bulsara, Nigel G Stocks
Inspired by recent results on self-tunability in the outer hair cells of the mammalian cochlea, we describe an array of magnetic sensors where each individual sensor can self-tune to an optimal operating regime. The self-tuning gives the array its "biomimetic" features. We show that the overall performance of the array can, as expected, be improved by increasing the number of sensors but, however, coupling between sensors reduces the overall performance even though the individual sensors in the system could see an improvement...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28414275/a-new-hypothesis-on-the-frequency-discrimination-of-the-cochlea
#3
Erdoğan Bulut, Cem Uzun, Levent Öztürk, Pınar Turan, Mehmet Kanter, Serap Arbak
OBJECTIVE: Medial olivocochlear efferent (MOCE) neurons innervate outer hair cells (OHCs) of the cochlea, which in turn leads to basilar membrane motion. We hypothesized that MOCE-induced alterations in basilar membrane motion, independent of traveling waves, is responsible for the cochlear frequency discrimination of sound. MATERIALS AND METHODS: Eleven guinea pigs underwent bilateral otoscopic and audiologic evaluations under general anesthesia. The study comprised two parts...
April 17, 2017: Journal of International Advanced Otology
https://www.readbyqxmd.com/read/28413076/detection-of-endolymphatic-hydrops-using-traditional-mr-imaging-sequences
#4
John H Keller, Barry E Hirsch, Ryan S Marovich, Barton F Branstetter
PURPOSE: The purpose of this study was to determine whether Meniere's disease (MD) produces endolymphatic cavity size changes that are detectable using unenhanced high-resolution T2-weighted MRI. MATERIALS & METHODS: This retrospective case-control study included patients with documented MD who had a high-resolution T2-weighted or steady-state free procession MRI of the temporal bones within one month of diagnosis, between 2002 and 2015. Patients were compared to age- and sex- matched controls...
April 6, 2017: American Journal of Otolaryngology
https://www.readbyqxmd.com/read/28405467/anti-apoptotic-effect-of-dexamethasone-in-an-ototoxicity-model
#5
Jin Ho Lee, Se Heang Oh, Tae Ho Kim, Yoon Young Go, Jae-Jun Song
BACKGROUND: Dexamethasone (DEX) is used for the treatment of various inner ear diseases. However, the molecular mechanism of DEX on gentamicin induced hair cell damage is not known. Therefore, this study investigated the protective effect of DEX on gentamicin (GM)-induced ototoxicity and the effect of GM on the expression of apoptosis related genes. METHODS: The protective effects of DEX were measured by phalloidin staining of explant cultures of organ of Corti from postnatal day 2-3 mice with GM-induced hair cell loss...
2017: Biomaterials Research
https://www.readbyqxmd.com/read/28402854/in%C3%A2-vivo-interplay-between-p27-kip1-gata3-atoh1-and-pou4f3-converts-non-sensory-cells-to-hair-cells-in-adult-mice
#6
Bradley J Walters, Emily Coak, Jennifer Dearman, Grace Bailey, Tetsuji Yamashita, Bryan Kuo, Jian Zuo
Hearing loss is widespread and persistent because mature mammalian auditory hair cells (HCs) are nonregenerative. In mice, the ability to regenerate HCs from surrounding supporting cells (SCs) declines abruptly after postnatal maturation. We find that combining p27(Kip1) deletion with ectopic ATOH1 expression surmounts this age-related decline, leading to conversion of SCs to HCs in mature mouse cochleae and after noise damage. p27(Kip1) deletion, independent of canonical effects on Rb-family proteins, upregulated GATA3, a co-factor for ATOH1 that is lost from SCs with age...
April 11, 2017: Cell Reports
https://www.readbyqxmd.com/read/28400833/over-expression-of-myosin7a-in-cochlear-hair-cells-of-circling-mice
#7
Yoo Yeon Kim, Hajin Nam, Harry Jung, Boyoung Kim, Jun Gyo Suh
Circling mouse (C57BL/6J-cir/cir) deleted the transmembrane inner ear (Tmie) gene is an animal model for human non-syndromic recessive deafness, DFNB6. In circling mouse, hair cells in the cochlea have degenerated and hair bundles have become irregularity as time goes on. Tmie protein carries out a function of the mechanoelectrical transduction channel in cochlear hair cells. Myosin7a (MYO7A) protein has key roles in development of the cochlear hair bundles as well as in the function of cochlear hair cells...
March 2017: Laboratory Animal Research
https://www.readbyqxmd.com/read/28399691/effect-of-aldosterone-on-cochlear-af9-expression-and-hearing-in-guinea-pig
#8
Li Qin, Biyun Zhang, Qianying Wang, Duanchao Li, Xiaoli Luo, Shixun Zhong
CONCLUSIONS: Af9 protein in cochlea may be closely related to endolymph regulation by aldosterone and thus may be involved in pathogenesis of endolymphatic hydrops (EH). OBJECTIVES: EH is the pathological characteristic of Ménière's disease (MD). Aldosterone could induce EH, but its relationship with MD is still controversial. The aim of the present study is to investigate the Af9 protein expression in guinea pig cochlea and regulation of Af9 expression and cochlear function by aldosterone...
April 11, 2017: Acta Oto-laryngologica
https://www.readbyqxmd.com/read/28394651/reference-thresholds-for-the-ten-hl-test-for-people-with-normal-hearing
#9
Andreas S Hansen, Øyvind Raen, Brian C J Moore
OBJECTIVE: To estimate normative values and repeatability of thresholds for the TEN(HL) test for diagnosing dead regions in the cochlea, as a function of signal frequency, TEN(HL) level, age and gender. DESIGN: The TEN(HL) test was administered twice for each ear of each participant using signal frequencies from 0.5 to 4 kHz and TEN(HL) levels of 30, 50 and 70 dB HL/ERBN. STUDY SAMPLE: In all, 29 young participants and 8 older participants were tested...
April 10, 2017: International Journal of Audiology
https://www.readbyqxmd.com/read/28390777/on-the-role-of-ephrina2-in-auditory-function
#10
Neil J Ingham, Karen P Steel, Uwe Drescher
Recent findings suggest that the manipulation of the EphA/ephrinA system can improve hearing threshold sensitivity in the auditory system (Yates et al., 2014). These results appear to open-up the possibility that pharmacological manipulation of this system could lead to the development of treatments to cure some types of hearing loss. As a first step towards this goal, we have performed a further series of auditory brainstem evoked potential recordings on ephrinA2 homozygous knockout mice and their wildtype littermates in order to replicate the previously reported findings...
April 5, 2017: Hearing Research
https://www.readbyqxmd.com/read/28390604/protective-role-of-misoprostol-in-prevention-of-gentamicin-ototoxicity
#11
Murat Dogan, Halil Polat, Mehmet Yasar, Ali Bayram, Duran Karatas, İbrahim Hira, Ahmet Kale, Fatma Senel, İbrahim Özcan
OBJECTIVES: To demonstrate potential protective effect of misoprostol on cochlear toxicity caused by gentamicin with electrophysiological tests and histopathological studies. MATERIALS AND METHODS: The study included 80 ears of 40 rats with normal hearing threshold and DPOAE value in both ears. Animals were assigned into 4 groups. The rats were randomized into 4 groups. Group I (n = 10): Gentamicin, Group II (n = 10): Gentamicin plus misoprostol, Group III (n = 10): Saline; Group IV (n = 10): Misoprostol...
May 2017: International Journal of Pediatric Otorhinolaryngology
https://www.readbyqxmd.com/read/28388854/auditory-adaptation-testing-as-a-tool-for-investigating-tinnitus-origin-two-patients-with-vestibular-schwannoma
#12
Carol A Silverman, Shlomo Silman, Michele B Emmer
OBJECTIVE: To enhance the understanding of tinnitus origin by disseminating two case studies of vestibular schwannoma (VS) involving behavioural auditory adaptation testing (AAT). DESIGN: Retrospective case study. STUDY SAMPLE: Two adults who presented with unilateral, non-pulsatile subjective tinnitus and bilateral normal-hearing sensitivity. At the initial evaluation, the otolaryngologic and audiologic findings were unremarkable, bilaterally...
April 7, 2017: International Journal of Audiology
https://www.readbyqxmd.com/read/28388662/scanning-laser-optical-tomography-for-in-toto-imaging-of-the-murine-cochlea
#13
Lena Nolte, Nadine Tinne, Jennifer Schulze, Dag Heinemann, Georgios C Antonopoulos, Heiko Meyer, Hans Gerd Nothwang, Thomas Lenarz, Alexander Heisterkamp, Athanasia Warnecke, Tammo Ripken
The mammalian cochlea is a complex macroscopic structure due to its helical shape and the microscopic arrangements of the individual layers of cells. To improve the outcomes of hearing restoration in deaf patients, it is important to understand the anatomic structure and composition of the cochlea ex vivo. Hitherto, only one histological technique based on confocal laser scanning microscopy and optical clearing has been developed for in toto optical imaging of the murine cochlea. However, with a growing size of the specimen, e...
2017: PloS One
https://www.readbyqxmd.com/read/28387239/survival-of-human-embryonic-stem-cells-implanted-in-the-guinea-pig-auditory-epithelium
#14
Min Young Lee, Sandra Hackelberg, Kari L Green, Kelly G Lunghamer, Takaomi Kurioka, Benjamin R Loomis, Donald L Swiderski, R Keith Duncan, Yehoash Raphael
Hair cells in the mature cochlea cannot spontaneously regenerate. One potential approach for restoring hair cells is stem cell therapy. However, when cells are transplanted into scala media (SM) of the cochlea, they promptly die due to the high potassium concentration. We previously described a method for conditioning the SM to make it more hospitable to implanted cells and showed that HeLa cells could survive for up to a week using this method. Here, we evaluated the survival of human embryonic stem cells (hESC) constitutively expressing GFP (H9 Cre-LoxP) in deaf guinea pig cochleae that were pre-conditioned to reduce potassium levels...
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28384958/application-of-curved-mpr-algorithm-to-high-resolution-3-dimensional-t2-weighted-ciss-images-for-virtual-uncoiling-of-membranous-cochlea-as-an-aid-for-cochlear-morphometry
#15
Joish Upendra Kumar, Y Kavitha
INTRODUCTION: With the use of various surgical techniques, types of implants, the preoperative assessment of cochlear dimensions is becoming increasingly relevant prior to cochlear implantation. High resolution CISS protocol MRI gives a better assessment of membranous cochlea, cochlear nerve, and membranous labyrinth. Curved Multiplanar Reconstruction (MPR) algorithm provides better images that can be used for measuring dimensions of membranous cochlea. AIM: To ascertain the value of curved multiplanar reconstruction algorithm in high resolution 3-Dimensional T2 Weighted Gradient Echo Constructive Interference Steady State (3D T2W GRE CISS) imaging for accurate morphometry of membranous cochlea...
February 2017: Journal of Clinical and Diagnostic Research: JCDR
https://www.readbyqxmd.com/read/28384320/direct-administration-of-2-hydroxypropyl-beta-cyclodextrin-into-guinea-pig-cochleae-effects-on-physiological-and-histological-measurements
#16
J T Lichtenhan, K Hirose, C A Buchman, R K Duncan, A N Salt
2-Hydroxypropyl-Beta-Cyclodextrin (HPβCD) can be used to treat Niemann-Pick type C disease, Alzheimer's disease, and atherosclerosis. But, a consequence is that HPβCD can cause hearing loss. HPβCD was recently found to be toxic to outer hair cells (OHCs) in the organ of Corti. Previous studies on the chronic effects of in vivo HPβCD toxicity did not know the intra-cochlear concentration of HPβCD and attributed variable effects on OHCs to indirect drug delivery to the cochlea. We studied the acute effects of known HPβCD concentrations administered directly into intact guinea pig cochleae...
2017: PloS One
https://www.readbyqxmd.com/read/28383464/intra-and-interobserver-variability-of-cochlear-length-measurements-in-clinical-ct
#17
John E Iyaniwura, Mai Elfarnawany, Sadegh Riyahi-Alam, Manas Sharma, Zahra Kassam, Yves Bureau, Lorne S Parnes, Hanif M Ladak, Sumit K Agrawal
HYPOTHESIS: The cochlear A-value measurement exhibits significant inter- and intraobserver variability, and its accuracy is dependent on the visualization method in clinical computed tomography (CT) images of the cochlea. BACKGROUND: An accurate estimate of the cochlear duct length (CDL) can be used to determine electrode choice, and frequency map the cochlea based on the Greenwood equation. Studies have described estimating the CDL using a single A-value measurement, however the observer variability has not been assessed...
April 5, 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28382742/mechanical-tuning-and-amplification-within-the-apex-of-the-guinea-pig-cochlea
#18
Alberto Recio-Spinoso, John S Oghalai
The popular notion of mammalian cochlear function is that auditory nerves are tuned to respond best to different sound frequencies because basilar membrane vibration is mechanically tuned to different frequencies along its length. However, this concept has only been demonstrated in regions of the cochlea tuned to frequencies >7 kHz, not in regions sensitive to lower frequencies where human speech is encoded. Here, we overcame historical technical limitations and non-invasively measured sound-induced vibrations at four locations distributed over the apical two turns of the guinea pig cochlea...
April 6, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28379904/automatic-localization-of-cochlear-implant-electrode-contacts-in-ct
#19
Edwin Bennink, Jeroen P M Peters, Anne W Wendrich, Evert-Jan Vonken, Gijsbert A van Zanten, Max A Viergever
OBJECTIVES: Determining the exact location of cochlear implant (CI) electrode contacts after implantation is important, as it helps quantifying the relation between CI positioning and hearing outcome. Unfortunately, localization of individual contacts can be difficult, because the spacing between the electrode contacts is near the spatial resolution limit of high-resolution clinical computed tomography (CT) scanners. This study introduces and examines a simple, automatic method for the localization of intracochlear electrode contacts...
April 4, 2017: Ear and Hearing
https://www.readbyqxmd.com/read/28373550/resistance-to-action-potential-depression-of-a-rat-axon-terminal-in-vivo
#20
Martijn C Sierksma, J Gerard G Borst
The shape of the presynaptic action potential (AP) has a strong impact on neurotransmitter release. Because of the small size of most terminals in the central nervous system, little is known about the regulation of their AP shape during natural firing patterns in vivo. The calyx of Held is a giant axosomatic terminal in the auditory brainstem, whose biophysical properties have been well studied in slices. Here, we made whole-cell recordings from calyceal terminals in newborn rat pups. The calyx showed a characteristic burst firing pattern, which has previously been shown to originate from the cochlea...
April 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
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