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Sample records for chick cochlear hair

  1. Acoustic trauma increases cochlear and hair cell uptake of gentamicin.

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    Hongzhe Li

    Full Text Available BACKGROUND: Exposure to intense sound or high doses of aminoglycoside antibiotics can increase hearing thresholds, induce cochlear dysfunction, disrupt hair cell morphology and promote hair cell death, leading to permanent hearing loss. When the two insults are combined, synergistic ototoxicity occurs, exacerbating cochlear vulnerability to sound exposure. The underlying mechanism of this synergism remains unknown. In this study, we tested the hypothesis that sound exposure enhances the intra-cochlear trafficking of aminoglycosides, such as gentamicin, leading to increased hair cell uptake of aminoglycosides and subsequent ototoxicity. METHODS: Juvenile C57Bl/6 mice were exposed to moderate or intense sound levels, while fluorescently-conjugated or native gentamicin was administered concurrently or following sound exposure. Drug uptake was then examined in cochlear tissues by confocal microscopy. RESULTS: Prolonged sound exposure that induced temporary threshold shifts increased gentamicin uptake by cochlear hair cells, and increased gentamicin permeation across the strial blood-labyrinth barrier. Enhanced intra-cochlear trafficking and hair cell uptake of gentamicin also occurred when prolonged sound, and subsequent aminoglycoside exposure were temporally separated, confirming previous observations. Acute, concurrent sound exposure did not increase cochlear uptake of aminoglycosides. CONCLUSIONS: Prolonged, moderate sound exposures enhanced intra-cochlear aminoglycoside trafficking into the stria vascularis and hair cells. Changes in strial and/or hair cell physiology and integrity due to acoustic overstimulation could increase hair cell uptake of gentamicin, and may represent one mechanism of synergistic ototoxicity.

  2. THE COCHLEAR AMPLIFIER:IS IT HAIR BUNDLE MOTION OF OUTER HAIR CELLS?

    Institute of Scientific and Technical Information of China (English)

    LI Yi; He David Z

    2014-01-01

    Cochlear outer hair cells (OHCs) are involved in a mechanical feedback loop in which the fast somatic motility of OHCs is required for cochlear amplification. Alternatively, amplification is thought to arise from active hair bundle movements ob-served in non-mammalian hair cells. We measured the voltage-evoked hair bundle motions in the gerbil cochlea to determine if such movements are also present in mammalian OHCs. The OHCs displayed a large hair bundle movement that was not based on mechanotransducer channels but based on somatic motility. Significantly, bundle movements were able to generate radial motion of the tectorial membrane in situ. This result implies that the motility-associated hair bundle motion may be part of the cochlear amplifier.

  3. Electrokinetic shape changes of cochlear outer hair cells

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    Kachar, Bechara; Brownell, William E.; Altschuler, Richard; Fex, Jörgen

    1986-07-01

    Rapid mechanical changes have been associated with electrical activity in a variety of non-muscle excitable cells1-5. Recently, mechanical changes have been reported in cochlear hair cells6-8. Here we describe electrically evoked mechanical changes in isolated cochlear outer hair cells (OHCs) with characteristics which suggest that direct electrokinetic phenomena are implicated in the response. OHCs make up one of two mechanosensitive hair cell populations in the mammalian cochlea; their role may be to modulate the micromechanical properties of the hearing organ through mechanical feedback mechanisms6-10. In the experiments described here, we applied sinusoidally modulated electrical potentials across isolated OHCs; this produced oscillatory elongation and shortening of the cells and oscillatory displacements of intracellular organdies. The movements were a function of the direction and strength of the electrical field, were inversely related to the ionic concentration of the medium, and occurred in the presence of metabolic uncouplers. The cylindrical shape of the OHCs and the presence of a system of membranes within the cytoplasm-laminated cisternae11-may provide the anatomical substrate for electrokinetic phenomena such as electro-osmosis12,13.

  4. Ion flow in cochlear hair cells and the regulation of hearing sensitivity.

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    Patuzzi, Robert

    2011-10-01

    This paper discusses how ion transport proteins in the hair cells of the mammalian cochlea work to produce a sensitive but stable hearing organ. The transport proteins in the inner and outer hair cells are summarized (including their current voltage characteristics), and the roles of these proteins in determining intracellular Ca(2+), membrane potential, and ultimately cochlear sensitivity are discussed. The paper also discusses the role of the Ca(2+) sequestration sacs in outer hair cells in the autoregulation of hair cell membrane potential and cochlear gain, and how the underdamped control of Ca(2+) within these sacs may produce the observed slow oscillations in cochlear sensitivity and otoacoustic emissions after cochlear perturbations, including perilymphatic perfusions and prolonged low-frequency tones. The relative insensitivity of cochlear gain to short-term changes in the endocochlear potential is also discussed.

  5. The temporal characteristics of Ca2+ entry through L-type and T-type Ca2+ channels shape exocytosis efficiency in chick auditory hair cells during development.

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    Levic, Snezana; Dulon, Didier

    2012-12-01

    During development, synaptic exocytosis by cochlear hair cells is first initiated by patterned spontaneous Ca(2+) spikes and, at the onset of hearing, by sound-driven graded depolarizing potentials. The molecular reorganization occurring in the hair cell synaptic machinery during this developmental transition still remains elusive. We characterized the changes in biophysical properties of voltage-gated Ca(2+) currents and exocytosis in developing auditory hair cells of a precocial animal, the domestic chick. We found that immature chick hair cells (embryonic days 10-12) use two types of Ca(2+) currents to control exocytosis: low-voltage-activating, rapidly inactivating (mibefradil sensitive) T-type Ca(2+) currents and high-voltage-activating, noninactivating (nifedipine sensitive) L-type currents. Exocytosis evoked by T-type Ca(2+) current displayed a fast release component (RRP) but lacked the slow sustained release component (SRP), suggesting an inefficient recruitment of distant synaptic vesicles by this transient Ca(2+) current. With maturation, the participation of L-type Ca(2+) currents to exocytosis largely increased, inducing a highly Ca(2+) efficient recruitment of an RRP and an SRP component. Notably, L-type-driven exocytosis in immature hair cells displayed higher Ca(2+) efficiency when triggered by prerecorded native action potentials than by voltage steps, whereas similar efficiency for both protocols was found in mature hair cells. This difference likely reflects a tighter coupling between release sites and Ca(2+) channels in mature hair cells. Overall, our results suggest that the temporal characteristics of Ca(2+) entry through T-type and L-type Ca(2+) channels greatly influence synaptic release by hair cells during cochlear development.

  6. An electrical tuning mechanism in turtle cochlear hair cells.

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    Crawford, A C; Fettiplace, R

    1981-03-01

    1. Intracellular recordings were made from single cochlear hair cells in the isolated half-head of the turtle. The electrical responses of the cells were recorded under two conditions: (a) when the ear was stimulated with low-intensity tones of different frequencies and (b) when current steps were injected through the intracellular electrode. The aim of the experiments was to evaluate the extent to which the cochlea's frequency selectivity could be accounted for by the electrical properties of the hair cells.2. At low levels of acoustic stimulation, the amplitude of the hair cell's receptor potential was proportional to sound pressure. The linear tuning curve, which is defined as the sensitivity of the cell as a function of frequency when the cell is operating in its linear range, was measured for a number of hair cells with characteristic frequencies from 86 Hz to 425 Hz.3. A rectangular current passed into a hair cell elicited a membrane potential change consisting of a damped oscillation superimposed on a step. Small currents produced symmetrical oscillations at the beginning and end of the pulse. Larger currents increased the initial ringing frequency if depolarizing and decreased it if hyperpolarizing.4. For small currents the frequency of the oscillations and the quality factor (Q) of the electrical resonance derived from the decay of the oscillations were close to the characteristic frequency and Q of the hair-cell linear tuning curve obtained from sound presentations.5. The hair cell's membrane potential change to small-current pulses or low-intensity tone bursts could be largely described by representing the hair cell as a simple electrical resonator consisting of an inductance, resistor and capacitor.6. When step displacements of 29-250 nm were applied to a micropipette, placed just outside a hair cell in the basilar papilla, an initial periodic firing of impulses could be recorded from single fibres in the auditory nerve. Currents of up to 1 nA, injected

  7. Cochlear outer hair cells undergo an apical circumference remodeling constrained by the hair bundle shape.

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    Etournay, Raphaël; Lepelletier, Léa; Boutet de Monvel, Jacques; Michel, Vincent; Cayet, Nadège; Leibovici, Michel; Weil, Dominique; Foucher, Isabelle; Hardelin, Jean-Pierre; Petit, Christine

    2010-04-01

    Epithelial cells acquire diverse shapes relating to their different functions. This is particularly relevant for the cochlear outer hair cells (OHCs), whose apical and basolateral shapes accommodate the functioning of these cells as mechano-electrical and electromechanical transducers, respectively. We uncovered a circumferential shape transition of the apical junctional complex (AJC) of OHCs, which occurs during the early postnatal period in the mouse, prior to hearing onset. Geometric analysis of the OHC apical circumference using immunostaining of the AJC protein ZO1 and Fourier-interpolated contour detection characterizes this transition as a switch from a rounded-hexagon to a non-convex circumference delineating two lateral lobes at the neural side of the cell, with a negative curvature in between. This shape tightly correlates with the 'V'-configuration of the OHC hair bundle, the apical mechanosensitive organelle that converts sound-evoked vibrations into variations in cell membrane potential. The OHC apical circumference remodeling failed or was incomplete in all the mouse mutants affected in hair bundle morphogenesis that we tested. During the normal shape transition, myosin VIIa and myosin II (A and B isoforms) displayed polarized redistributions into and out of the developing lobes, respectively, while Shroom2 and F-actin transiently accumulated in the lobes. Defects in these redistributions were observed in the mutants, paralleling their apical circumference abnormalities. Our results point to a pivotal role for actomyosin cytoskeleton tensions in the reshaping of the OHC apical circumference. We propose that this remodeling contributes to optimize the mechanical coupling between the basal and apical poles of mature OHCs.

  8. Cochlear gene therapy with ancestral AAV in adult mice: complete transduction of inner hair cells without cochlear dysfunction

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    Suzuki, Jun; Hashimoto, Ken; Xiao, Ru; Vandenberghe, Luk H.; Liberman, M. Charles

    2017-01-01

    The use of viral vectors for inner ear gene therapy is receiving increased attention for treatment of genetic hearing disorders. Most animal studies to date have injected viral suspensions into neonatal ears, via the round window membrane. Achieving transduction of hair cells, or sensory neurons, throughout the cochlea has proven difficult, and no studies have been able to efficiently transduce sensory cells in adult ears while maintaining normal cochlear function. Here, we show, for the first time, successful transduction of all inner hair cells and the majority of outer hair cells in an adult cochlea via virus injection into the posterior semicircular canal. We used a “designer” AAV, AAV2/Anc80L65, in which the main capsid proteins approximate the ancestral sequence state of AAV1, 2, 8, and 9. Our injections also transduced ~10% of spiral ganglion cells and a much larger fraction of their satellite cells. In the vestibular sensory epithelia, the virus transduced large numbers of hair cells and virtually all the supporting cells, along with close to half of the vestibular ganglion cells. We conclude that this viral vector and this delivery route hold great promise for gene therapy applications in both cochlear and vestibular sense organs. PMID:28367981

  9. Sonic hedgehog initiates cochlear hair cell regeneration through downregulation of retinoblastoma protein

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    Lu, Na [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114 (United States); Chen, Yan [Central Laboratory, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Wang, Zhengmin [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Institute of Biomedical Sciences, Fudan University, Shanghai 200032 (China); Chen, Guoling [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Lin, Qin [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Otolaryngology Institute of Fujian Province, Fuzhou (China); Chen, Zheng-Yi, E-mail: Zheng-yi_chen@meei.harvard.edu [Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114 (United States); Li, Huawei, E-mail: hwli@shmu.edu.cn [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Institute of Biomedical Sciences, Fudan University, Shanghai 200032 (China)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer Shh activation in neonatal cochleae enhances sensory cell proliferation. Black-Right-Pointing-Pointer Proliferating supporting cells can transdifferentiate into hair cells. Black-Right-Pointing-Pointer Shh promotes proliferation by transiently modulating pRb activity. Black-Right-Pointing-Pointer Shh inhibits pRb by inhibiting transcription and increasing phosphorylation of pRb. -- Abstract: Cell cycle re-entry by cochlear supporting cells and/or hair cells is considered one of the best approaches for restoring hearing loss as a result of hair cell damage. To identify mechanisms that can be modulated to initiate cell cycle re-entry and hair cell regeneration, we studied the effect of activating the sonic hedgehog (Shh) pathway. We show that Shh signaling in postnatal rat cochleae damaged by neomycin leads to renewed proliferation of supporting cells and hair cells. Further, proliferating supporting cells are likely to transdifferentiate into hair cells. Shh treatment leads to inhibition of retinoblastoma protein (pRb) by increasing phosphorylated pRb and reducing retinoblastoma gene transcription. This results in upregulation of cyclins B1, D2, and D3, and CDK1. These results suggest that Shh signaling induces cell cycle re-entry in cochlear sensory epithelium and the production of new hair cells, in part by attenuating pRb function. This study provides an additional route to modulate pRb function with important implications in mammalian hair cell regeneration.

  10. Usherin is required for maintenance of retinal photoreceptors and normal development of cochlear hair cells

    OpenAIRE

    2007-01-01

    Usher syndrome type IIA (USH2A), characterized by progressive photoreceptor degeneration and congenital moderate hearing loss, is the most common subtype of Usher syndrome. In this article, we show that the USH2A protein, also known as usherin, is an exceptionally large (≈600-kDa) matrix protein expressed specifically in retinal photoreceptors and developing cochlear hair cells. In mammalian photoreceptors, usherin is localized to a spatially restricted membrane microdomain at the apical inne...

  11. Identifying components of the hair-cell interactome involved in cochlear amplification

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    Cheatham MaryAnn

    2009-03-01

    Full Text Available Abstract Background Although outer hair cells (OHCs play a key role in cochlear amplification, it is not fully understood how they amplify sound signals by more than 100 fold. Two competing or possibly complementary mechanisms, stereocilia-based and somatic electromotility-based amplification, have been considered. Lacking knowledge about the exceptionally rich protein networks in the OHC plasma membrane, as well as related protein-protein interactions, limits our understanding of cochlear function. Therefore, we focused on finding protein partners for two important membrane proteins: Cadherin 23 (cdh23 and prestin. Cdh23 is one of the tip-link proteins involved in transducer function, a key component of mechanoelectrical transduction and stereocilia-based amplification. Prestin is a basolateral membrane protein responsible for OHC somatic electromotility. Results Using the membrane-based yeast two-hybrid system to screen a newly built cDNA library made predominantly from OHCs, we identified two completely different groups of potential protein partners using prestin and cdh23 as bait. These include both membrane bound and cytoplasmic proteins with 12 being de novo gene products with unknown function(s. In addition, some of these genes are closely associated with deafness loci, implying a potentially important role in hearing. The most abundant prey for prestin (38% is composed of a group of proteins involved in electron transport, which may play a role in OHC survival. The most abundant group of cdh23 prey (55% contains calcium-binding domains. Since calcium performs an important role in hair cell mechanoelectrical transduction and amplification, understanding the interactions between cdh23 and calcium-binding proteins should increase our knowledge of hair cell function at the molecular level. Conclusion The results of this study shed light on some protein networks in cochlear hair cells. Not only was a group of de novo genes closely associated

  12. Mammalin cochlear supporting cells transdifferentiation into outer hair cells

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Objective To study the recovery of the outer hair cells in the bat cochlea after gentamicin exposure. Methods Bats were injected with a daily dose of gentamicin for 15 consecutive days and bromodeoxyuridine (BrdU) was given from day 16 to day 40 of this recovery phase. Hearing was assessed by overt acoustic behavior and auditory brainstem responses analysis, which was performed one day prior to the first injection and a day after the last injection (day 16). On day 40 animals were sacrificed for detection o...

  13. Mammalian Cochlear Hair Cell Regeneration and Ribbon Synapse Reformation

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    Xiaoling Lu

    2016-01-01

    Full Text Available Hair cells (HCs are the sensory preceptor cells in the inner ear, which play an important role in hearing and balance. The HCs of organ of Corti are susceptible to noise, ototoxic drugs, and infections, thus resulting in permanent hearing loss. Recent approaches of HCs regeneration provide new directions for finding the treatment of sensor neural deafness. To have normal hearing function, the regenerated HCs must be reinnervated by nerve fibers and reform ribbon synapse with the dendrite of spiral ganglion neuron through nerve regeneration. In this review, we discuss the research progress in HC regeneration, the synaptic plasticity, and the reinnervation of new regenerated HCs in mammalian inner ear.

  14. Synaptic and Golgi membrane recycling in cochlear hair cells.

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    Siegel, J H; Brownell, W E

    1986-06-01

    Membrane recycling in the mechanoreceptive sensory cells of the mammalian cochlea was studied by observing membrane-bound horseradish peroxidase (HRP) reaction product following brief in vivo exposure to the enzyme. In the inner hair cell (IHC), peroxidase was taken up into coated vesicles and became incorporated into synaptic vesicles surrounding presynaptic bodies, but much HRP was also transported to the apical zone where reaction product appeared in all components of the Golgi complex. Neither the subsurface cisternae nor a tubular network associated with clusters of mitochondria were labelled. Outer hair cells (OHCs) showed considerably less membrane-bound reaction product than IHCs, indicating less rapid plasmalemmal recycling. Most membrane-bound reaction product was contained in coated vesicles and small vacuoles in the synaptic zone, but was occasionally seen in multivesicular bodies in the most apical zone. No labelled organelles were detected in the large central region of the OHC. A diffuse staining of the cytoplasm, particularly pronounced in OHCs, often interfered with the evaluation of membrane-bound reaction product in OHCs. This staining pattern could be qualitatively reproduced in both IHCs and OHCs by incubating fixed segments of the organ of Corti in oxidized diaminobenzidine. The presence of labelled synaptic vesicles associated with presynaptic bodies of IHCs and OHCs suggests that they are formed from membrane retrieved from the plasmalemma. We found no evidence that the subsurface cisternae of IHCs or the laminated cisternae of OHCs are derived from the cell surface as they never contained reaction product.

  15. Nature of the motor element in electrokinetic shape changes of cochlear outer hair cells.

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    Dallos, P; Evans, B N; Hallworth, R

    1991-03-14

    It is the prevailing notion that cochlear outer hair cells function as mechanical effectors as well as sensory receptors. Electrically induced changes in the shape of mammalian outer hair cells, studied in vitro, are commonly assumed to represent an aspect of their effector process that may occur in vivo. The nature of the motile process is obscure, even though none of the established cellular motors can be involved. Although it is known that the motile response is under voltage control, it is uncertain whether the stimulus is a drop in the voltage along the long axis of the cell or variation in the transmembrane potential. We have now performed experiments with cells partitioned in differing degrees between two chambers. Applied voltage stimulates the cell membrane segments in opposite polarity to an amount dependent on the partitioning. The findings show, in accordance with previous suggestions, that the driving stimulus is a local transmembrane voltage drop and that the cellular motor consists of many independent elements, distributed along the cell membrane and its associated cortical structures. We further show that the primary action of the motor elements is along the longitudinal dimension of the cell without necessarily involving changes in intracellular hydrostatic pressure. This establishes the outer hair cell motor as unique among mechanisms that control cell shape.

  16. EHD4 and CDH23 are interacting partners in cochlear hair cells.

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    Sengupta, Soma; George, Manju; Miller, Katharine K; Naik, Khurram; Chou, Jonathan; Cheatham, Mary Ann; Dallos, Peter; Naramura, Mayumi; Band, Hamid; Zheng, Jing

    2009-07-24

    Cadherin 23 (CDH23), a transmembrane protein localized near the tips of hair cell stereocilia in the mammalian inner ear, is important for delivering mechanical signals to the mechano-electric transducer channels. To identify CDH23-interacting proteins, a membrane-based yeast two-hybrid screen of an outer hair cell (OHC) cDNA library was performed. EHD4, a member of the C-terminal EH domain containing a protein family involved in endocytic recycling, was identified as a potential interactor. To confirm the interaction, we first demonstrated the EHD4 mRNA expression in hair cells using in situ hybridization. Next, we showed that EHD4 co-localizes and co-immunoprecipitates with CDH23 in mammalian cells. Interestingly, the co-immunoprecipitation was found to be calcium-sensitive. To investigate the role of EHD4 in hearing, compound action potentials were measured in EHD4 knock-out (KO) mice. Although EHD4 KO mice have normal hearing sensitivity, analysis of mouse cochlear lysates revealed a 2-fold increase in EHD1, but no increase in EHD2 or EHD3, in EHD4 KO cochleae compared with wild type, suggesting that a compensatory increase in EHD1 levels may account for the absence of a hearing defect in EHD4 KO mice. Taken together, these data indicate that EHD4 is a novel CDH23-interacting protein that could regulate CDH23 trafficking/localization in a calcium-sensitive manner.

  17. Effects of neuroactive steroids on cochlear hair cell death induced by gentamicin.

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    Nakamagoe, Mariko; Tabuchi, Keiji; Nishimura, Bungo; Hara, Akira

    2011-12-11

    As neuroactive steroids, sex steroid hormones have non-reproductive effects. We previously reported that 17β-estradiol (βE2) had protective effects against gentamicin (GM) ototoxicity in the cochlea. In the present study, we examined whether the protective action of βE2 on GM ototoxicity is mediated by the estrogen receptor (ER) and whether other estrogens (17α-estradiol (αE2), estrone (E1), and estriol (E3)) and other neuroactive steroids, dehydroepiandrosterone (DHEA) and progesterone (P), have similar protective effects. The basal turn of the organ of Corti was dissected from Sprague-Dawley rats and cultured in a medium containing 100 μM GM for 48h. The effects of βE2 and ICI 182,780, a selective ER antagonist, were examined. In addition, the effects of other estrogens, DHEA and P were tested using this culture system. Loss of outer hair cells induced by GM exposure was compared among groups. βE2 exhibited a protective effect against GM ototoxicity, but its protective effect was antagonized by ICI 182,780. αE2, E1, and E3 also protected hair cells against gentamicin ototoxicity. DHEA showed a protective effect; however, the addition of ICI 182,780 did not affect hair cell loss. P did not have any effect on GM-induced outer hair cell death. The present findings suggest that estrogens and DHEA are protective agents against GM ototoxicity. The results of the ER antagonist study also suggest that the protective action of βE2 is mediated via ER but that of DHEA is not related to its conversion to estrogen and binding to ER. Further studies on neuroactive steroids may lead to new insights regarding cochlear protection.

  18. Gentamicin rapidly inhibits mitochondrial metabolism in high-frequency cochlear outer hair cells.

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    Heather C Jensen-Smith

    Full Text Available Aminoglycosides (AG, including gentamicin (GM, are the most frequently used antibiotics in the world and are proposed to cause irreversible cochlear damage and hearing loss (HL in 1/4 of the patients receiving these life-saving drugs. Akin to the results of AG ototoxicity studies, high-frequency, basal turn outer hair cells (OHCs preferentially succumb to multiple HL pathologies while inner hair cells (IHCs are much more resilient. To determine if endogenous differences in IHC and OHC mitochondrial metabolism dictate differential sensitivities to AG-induced HL, IHC- and OHC-specific changes in mitochondrial reduced nicotinamide adenine dinucleotide (NADH fluorescence during acute (1 h GM treatment were compared. GM-mediated decreases in NADH fluorescence and succinate dehydrogenase activity were observed shortly after GM application. High-frequency basal turn OHCs were found to be metabolically biased to rapidly respond to alterations in their microenvironment including GM and elevated glucose exposures. These metabolic biases may predispose high-frequency OHCs to preferentially produce cell-damaging reactive oxygen species during traumatic challenge. Noise-induced and age-related HL pathologies share key characteristics with AG ototoxicity, including preferential OHC loss and reactive oxygen species production. Data from this report highlight the need to address the role of mitochondrial metabolism in regulating AG ototoxicity and the need to illuminate how fundamental differences in IHC and OHC metabolism may dictate differences in HC fate during multiple HL pathologies.

  19. Diverse and Dynamic Expression Patterns of Voltage-Gated Ion Channel Genes in Rat Cochlear Hair Cells

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    Beisel, K. W.; Fritzsch, B.

    2003-02-01

    Both qualitative and quantitative differences in ion-channel conductances are observed along the tonotopic axis of the mammalian cochlea. We have used a molecular approach to characterize these longitudinal expression patterns of voltage-gated ion-channel (VgCN) superfamily members in the peripheral auditory system. Initially RT-PCR and sequence analyses identified the VgCN α and accessory subunits of the cochlear hair cell (HC). Next, whole mount in situ hybridizations demonstrated at least seven common longitudinal expression patterns with the apex tip and basal hook region having the greatest in disparity. These data suggest potential topological variations in hair-cell electrophysiological signatures and these gradients may contribute to cochlear HC's ability to function as efficient frequency analyzers.

  20. Direct effects of reactive oxygen species on cochlear outer hair cell shape in vitro.

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    Clerici, W J; DiMartino, D L; Prasad, M R

    1995-04-01

    Reactive oxygen species (ROS) have been implicated in the ototoxicity of various agents. This study examines the effects of superoxide anion (O2), hydroxyl radical (OH.) and hydrogen peroxide (H2O2), on isolated cochlear outer hair cell (OHC) morphology. OHCs were superfused with artificial perilymph (AP) or AP containing a specific ROS scavenger, and then with AP, ROS system or scavenger plus ROS system for 90 min. The generation of ROS as well as the scavenging properties of other agents were confirmed by specific biochemical assays. Control cells decreased 4.8% in mean length, and showed no obvious membrane damage. Generation of O2. or OH. resulted in high rates (85.7 and 42.9%, respectively) of bleb formation at the synaptic pole, and decreased (O2., 15.2%; OH., 17.3%) mean cell length. Length change and bleb formation rate were H2O2 concentration-dependent. 20 mM H2O2 led to 33.3% decreased mean cell length, and only 20% bleb formation; 0.1 mM H2O2 led to 83.3% bleb formation, with no length decrease. Superoxide dismutase, deferoxamine and catalase protected against O2., OH. and H2O2 effects, respectively. Bleb formation and diminished cell length likely represent differential lipid peroxidative outcomes at supra- and infranuclear membranes, and are consistent with effects of certain ototoxicants.

  1. Cochlear outer hair cell bio-inspired metamaterial with negative effective parameters

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    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Zhang, Siwen

    2016-05-01

    Inspired by periodical outer hair cells (OHCs) and stereocilia clusters of mammalian cochlear, a type of bio-inspired metamaterial with negative effective parameters based on the OHC structure is proposed. With the structural parameters modified and some common engineering materials adopted, the bio-inspired structure design with length scales of millimeter and lightweight is presented, and then, a bending wave bandgap in a favorable low-frequency with width of 55 Hz during the interval 21-76 or 116 Hz during the interval 57-173 Hz is obtained, i.e., the excellent low-frequency acoustic performance turns up. Compared with the local resonance unit in previous literatures, both the size and weight are greatly reduced in our bio-inspired structure. In addition, the lower edge of low-frequency bandgap is reduced by an order of magnitude, almost to the lower limit frequency of the hearing threshold as well, which achieves an important breakthrough on the aspect of low-frequency and great significance on the noise and vibration reduction in low-frequency range.

  2. Unconventional molecular regulation of synaptic vesicle replenishment in cochlear inner hair cells.

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    Vogl, Christian; Cooper, Benjamin H; Neef, Jakob; Wojcik, Sonja M; Reim, Kerstin; Reisinger, Ellen; Brose, Nils; Rhee, Jeong-Seop; Moser, Tobias; Wichmann, Carolin

    2015-02-15

    Ribbon synapses of cochlear inner hair cells (IHCs) employ efficient vesicle replenishment to indefatigably encode sound. In neurons, neuroendocrine and immune cells, vesicle replenishment depends on proteins of the mammalian uncoordinated 13 (Munc13, also known as Unc13) and Ca(2+)-dependent activator proteins for secretion (CAPS) families, which prime vesicles for exocytosis. Here, we tested whether Munc13 and CAPS proteins also regulate exocytosis in mouse IHCs by combining immunohistochemistry with auditory systems physiology and IHC patch-clamp recordings of exocytosis in mice lacking Munc13 and CAPS isoforms. Surprisingly, we did not detect Munc13 or CAPS proteins at IHC presynaptic active zones and found normal IHC exocytosis as well as auditory brainstem responses (ABRs) in Munc13 and CAPS deletion mutants. Instead, we show that otoferlin, a C2-domain protein that is crucial for vesicular fusion and replenishment in IHCs, clusters at the plasma membrane of the presynaptic active zone. Electron tomography of otoferlin-deficient IHC synapses revealed a reduction of short tethers holding vesicles at the active zone, which might be a structural correlate of impaired vesicle priming in otoferlin-deficient IHCs. We conclude that IHCs use an unconventional priming machinery that involves otoferlin.

  3. Addition of exogenous NAD+ prevents mefloquine-induced neuroaxonal and hair cell degeneration through reduction of caspase-3-mediated apoptosis in cochlear organotypic cultures.

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    Dalian Ding

    Full Text Available BACKGROUND: Mefloquine is widely used for the treatment of malaria. However, this drug is known to induce neurological side effects including depression, anxiety, balance disorder, and sensorineural hearing loss. Yet, there is currently no treatment for these side effects. PRINCIPAL FINDINGS: In this study, we show that the coenzyme NAD(+, known to play a critical role in maintaining the appropriate cellular redox environment, protects cochlear axons and sensory hair cells from mefloquine-induced degeneration in cultured rat cochleae. Mefloquine alone destroyed hair cells and nerve fiber axons in rat cochlear organotypics cultures in a dose-dependent manner, while treatment with NAD(+ protected axons and hair cells from mefloquine-induced degeneration. Furthermore, cochlear organs treated with mefloquine showed increased oxidative stress marker levels, including superoxide and protein carbonyl, and increased apoptosis marker levels, including TUNEL-positive nuclei and caspases-3. Treatment with NAD(+ reduced the levels of these oxidative stress and apoptosis markers. CONCLUSIONS/SIGNIFICANCE: Taken together, our findings suggest that that mefloquine disrupts the cellular redox environment and induces oxidative stress in cochlear hair cells and nerve fibers leading to caspases-3-mediated apoptosis of these structures. Exogenous NAD(+ suppresses mefloquine-induced oxidative stress and prevents the degeneration of cochlear axons and sensory hair cells caused by mefloquine treatment.

  4. Theory of electrically driven shape changes of cochlear outer hair cells.

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    Dallos, P; Hallworth, R; Evans, B N

    1993-07-01

    1. A theory of cochlear outer hair cell electromotility is developed and specifically applied to somatic shape changes elicited in a microchamber. The microchamber permits the arbitrary electrical and mechanical partitioning of the outer hair cell along its length. This means that the two partitioned segments are stimulated with different input voltages and undergo different shape changes. Consequently, by imposing more constraints than other methods, experiments in the microchamber are particularly suitable for testing different theories of outer hair cell motility. 2. The present model is based on simple hypotheses. They include a distributed motor associated with the cell membrane or cortex and the assumption that the displacement generated by the motor is related to the transmembrane voltage across the associated membrane element. It is expected that the force generated by the motor is counterbalanced by an elastic restoring force indigenous to the cell membrane and cortex, and a tensile force due to intracellular pressure. It is assumed that all changes take place while total cell volume is conserved. The above elements of the theory taken together permit the development of qualitative and quantitative predictions about the expected motile responses of both partitioned segments of the cell. Only a DC treatment is offered here. 3. Both a linear motor and an expanded treatment that incorporates a stochastic molecular motor model are considered. The latter is represented by a two-state Boltzmann process. We show that the linear motor treatment is an appropriate extrapolation of the stochastic motor theory for the case of small voltage driving signals. Comparison of experimental results with model responses permits the estimation of model parameters. Good match of data is obtained if it is assumed that the molecular motors undergo conformational length changes of 0.7-1.0 nm, that they have an effective displacement vector at approximately -20 degrees with the long

  5. Resveratrol attenuates CoCl2-induced cochlear hair cell damage through upregulation of Sirtuin1 and NF-κB deacetylation.

    Directory of Open Access Journals (Sweden)

    Ping Wang

    Full Text Available The goals of this study were to investigate the effects of hypoxia on cochlear hair cell damage, and to explore the role of sirtuin1 in hypoxia-induced hair cell damage. Cochlear organotypic cultures from postnatal day 4 rats were used in this study. Hypoxia was induced by treating cochlear explants with CoCl2. Cochlear cultures were treated with CoCl2 alone or in combination with the sirtuin1 activator resveratrol and the sirtuin1 inhibitor sirtinol. Hair cell damage was identified by phalloidin staining and imaged using scanning electron microscopy. RT-PCR and Western blot analyses were used to detect the expression of sirtuin1 and acetylated nuclear factor-κB (NF-κB. Low concentrations of CoCl2 (100-200 μM did not cause an obvious change in the number and morphology of hair cells, whereas higher concentrations of CoCl2 (300-400 μM induced swelling of hair cells, accompanied by cell loss. Increased sirtuin1 expression was induced by CoCl2 at 100 to 200 μM, but not at 400 μM. NF-κB acetylation was significantly increased in explants treated with 400 μM CoCl2. Pretreatment with resveratrol prevented CoCl2-induced hair cell loss and acetylation of NF-κB. The protective effect of resveratrol was significantly reduced by sirtinol. CoCl2 induces hair cell damage in organotypic cochleae cultures. Resveratrol attenuates CoCl2-induced cochlear hair cell damage possibly via activation of sirtuin1, which deacetylates NF-κB.

  6. The actin-binding proteins eps8 and gelsolin have complementary roles in regulating the growth and stability of mechanosensory hair bundles of mammalian cochlear outer hair cells.

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    Jennifer Olt

    Full Text Available Sound transduction depends upon mechanosensitive channels localized on the hair-like bundles that project from the apical surface of cochlear hair cells. Hair bundles show a stair-case structure composed of rows of stereocilia, and each stereocilium contains a core of tightly-packed and uniformly-polarized actin filaments. The growth and maintenance of the stereociliary actin core are dynamically regulated. Recently, it was shown that the actin-binding protein gelsolin is expressed in the stereocilia of outer hair cells (OHCs and in its absence they become long and straggly. Gelsolin is part of a whirlin scaffolding protein complex at the stereocilia tip, which has been shown to interact with other actin regulatory molecules such as Eps8. Here we investigated the physiological effects associated with the absence of gelsolin and its possible overlapping role with Eps8. We found that, in contrast to Eps8, gelsolin does not affect mechanoelectrical transduction during immature stages of development. Moreover, OHCs from gelsolin knockout mice were able to mature into fully functional sensory receptors as judged by the normal resting membrane potential and basolateral membrane currents. Mechanoelectrical transducer current in gelsolin-Eps8 double knockout mice showed a profile similar to that observed in the single mutants for Eps8. We propose that gelsolin has a non-overlapping role with Eps8. While Eps8 is mainly involved in the initial growth of stereocilia in both inner hair cells (IHCs and OHCs, gelsolin is required for the maintenance of mature hair bundles of low-frequency OHCs after the onset of hearing.

  7. NaHS Protects Cochlear Hair Cells from Gentamicin-Induced Ototoxicity by Inhibiting the Mitochondrial Apoptosis Pathway.

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    Yaodong Dong

    Full Text Available Aminoglycoside antibiotics such as gentamicin could cause ototoxicity in mammalians, by inducing oxidative stress and apoptosis in sensory hair cells of the cochlea. Sodium hydrosulfide (NaHS is reported to alleviate oxidative stress and apoptosis, but its role in protecting aminoglycoside-induced hearing loss is unclear. In this study, we investigated the anti-oxidant and anti-apoptosis effect of NaHS in in vitro cultured House Ear Institute-Organ of Corti 1 (HEI-OC1 cells and isolated mouse cochlea. Results from cultured HEI-OC1 cells and cochlea consistently indicated that NaHS exhibited protective effects from gentamicin-induced ototoxicity, evident by maintained cell viability, hair cell number and cochlear morphology, reduced reactive oxygen species production and mitochondrial depolarization, as well as apoptosis activation of the intrinsic pathway. Moreover, in the isolated cochlear culture, NaHS was also demonstrated to protect the explant from gentamicin-induced mechanotransduction loss. Our study using multiple in vitro models revealed for the first time, the potential of NaHS as a therapeutic agent in protecting against aminoglycoside-induced hearing loss.

  8. NaHS Protects Cochlear Hair Cells from Gentamicin-Induced Ototoxicity by Inhibiting the Mitochondrial Apoptosis Pathway

    Science.gov (United States)

    Dong, Yaodong; Liu, Dongliang; Hu, Yue; Ma, Xiulan

    2015-01-01

    Aminoglycoside antibiotics such as gentamicin could cause ototoxicity in mammalians, by inducing oxidative stress and apoptosis in sensory hair cells of the cochlea. Sodium hydrosulfide (NaHS) is reported to alleviate oxidative stress and apoptosis, but its role in protecting aminoglycoside-induced hearing loss is unclear. In this study, we investigated the anti-oxidant and anti-apoptosis effect of NaHS in in vitro cultured House Ear Institute-Organ of Corti 1 (HEI-OC1) cells and isolated mouse cochlea. Results from cultured HEI-OC1 cells and cochlea consistently indicated that NaHS exhibited protective effects from gentamicin-induced ototoxicity, evident by maintained cell viability, hair cell number and cochlear morphology, reduced reactive oxygen species production and mitochondrial depolarization, as well as apoptosis activation of the intrinsic pathway. Moreover, in the isolated cochlear culture, NaHS was also demonstrated to protect the explant from gentamicin-induced mechanotransduction loss. Our study using multiple in vitro models revealed for the first time, the potential of NaHS as a therapeutic agent in protecting against aminoglycoside-induced hearing loss. PMID:26295804

  9. miR-29b overexpression induces cochlear hair cell apoptosis through the regulation of SIRT1/PGC-1α signaling: Implications for age-related hearing loss

    Science.gov (United States)

    Xue, Tao; Wei, Li; Zha, Ding-Jun; Qiu, Jian-Hua; Chen, Fu-Quan; Qiao, Li; Qiu, Yang

    2016-01-01

    It has been reported that the degeneration of cochlear hair cells is the typical cause of presbycusis (or age-related hearing loss). However, the molecular mechanisms that mediate cochlear hair cell apoptosis are not yet fully understood and there is no effective treatment for this disorder. MicroRNAs (miRNAs or miRs) have been increasingly shown to be associated with age-related diseases and are emerging as promising therapeutic targets. In this study, we investigated whether miR-29b is involved in the degeneration of cochlear hair cells. To examine our hypothesis, nuclear staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) were used to quantify the hair cell counts. RT-qPCR and western blot analysis were used to examine miR-29b/sirtuin 1 (SIRT1)/proliferator-activated receptor-gamma coactivator 1α (PGC-1α) signaling in cochlear hair cells. We found that there was a significant degeneration of cochlear hair cells and a higher expression of miR-29b in aged C57BL/6 mice compared with young mice. There was also an age-related decrease in the expression of SIRT1 and PGC-1α. In the inner ear cell line, HEI-OC1, miR-29b overexpression (by transfection with miR-29b mimic) inhibited SIRT1 and PGC-1α expression, leading to an increase in mitochondrial dysfunction and apoptosis. Moreover, the inhibition of miR-29b (by transfection with miR-29b inhibitor) increased SIRT1 and PGC-1α expression, while it decreased apoptosis. Taken together, our findings support a link between age-related cochlear hair cell apoptosis and miR-29b/SIRT1/PGC-1α signaling, which may present an attractive pharmacological target for the development of novel drugs for the treatment of age-related hearing loss. PMID:27635430

  10. The expression of NLRX1 in C57BL/6 mice cochlear hair cells: Possible relation to aging- and neomycin-induced deafness.

    Science.gov (United States)

    Yang, Qianqian; Sun, Gaoying; Cao, Zhixin; Yin, Haiyan; Qi, Qi; Wang, Jinghan; Liu, Wenwen; Bai, Xiaohui; Wang, Haibo; Li, Jianfeng

    2016-03-11

    Nucleotide-binding domain and leucine-rich-repeat-containing family member X1 (NLRX1) is a cytoplasmic pattern recognition receptor that is predominantly located in mitochondria, which is tightly related to mitochondrial damage, reactive oxygen species (ROS) production, inflammation and apoptosis. The present study was designed to explore whether NLRX1 expresses in C57BL/6 mice cochlear hair cells and, if so, to investigate the possible correlations between NLRX1 and hearing. The location and dynamic expression of NLRX1 were investigated by immunofluorescence, real-time PCR and Western blotting. Hearing thresholds of C57BL/6 mice were measured by auditory brainstem response (ABR). Moreover, the downstream inflammatory and apoptotic pathways regulated by NLRX1 were examined in age-related and neomycin-induced hair cell damage. Data showed that NLRX1 expressed in cytoplasm of C57BL/6 cochlear hair cells, especially in the cilia, which were essential for sound sensation. The expression of NLRX1 in hair cells increased as the mice grew up, and, decreased as they aged. Additionally, the activated apoptotic JNK pathway was detected in 9-month old mice with worse-hearing and 3-month old mice treated with neomycin. Overall, results indicate that NLRX1 may relate to hair cell maturity, hearing formation and maintenance, and promote hair cell apoptosis through JNK pathway induced by aging and neomycin.

  11. Induction of Functional Hair-Cell-Like Cells from Mouse Cochlear Multipotent Cells

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    Quanwen Liu

    2016-01-01

    Full Text Available In this paper, we developed a two-step-induction method of generating functional hair cells from inner ear multipotent cells. Multipotent cells from the inner ear were established and induced initially into progenitor cells committed to the inner ear cell lineage on the poly-L-lysine substratum. Subsequently, the committed progenitor cells were cultured on the mitotically inactivated chicken utricle stromal cells and induced into hair-cell-like cells containing characteristic stereocilia bundles. The hair-cell-like cells exhibited rapid permeation of FM1-43FX. The whole-cell patch-clamp technique was used to measure the membrane currents of cells differentiated for 7 days on chicken utricle stromal cells and analyze the biophysical properties of the hair-cell-like cells by recording membrane properties of cells. The results suggested that the hair-cell-like cells derived from inner ear multipotent cells were functional following differentiation in an enabling environment.

  12. Development and function of the voltage-gated sodium current in immature mammalian cochlear inner hair cells.

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    Tobias Eckrich

    Full Text Available Inner hair cells (IHCs, the primary sensory receptors of the mammalian cochlea, fire spontaneous Ca(2+ action potentials before the onset of hearing. Although this firing activity is mainly sustained by a depolarizing L-type (Ca(V1.3 Ca(2+ current (I(Ca, IHCs also transiently express a large Na(+ current (I(Na. We aimed to investigate the specific contribution of I(Na to the action potentials, the nature of the channels carrying the current and whether the biophysical properties of I(Na differ between low- and high-frequency IHCs. We show that I(Na is highly temperature-dependent and activates at around -60 mV, close to the action potential threshold. Its size was larger in apical than in basal IHCs and between 5% and 20% should be available at around the resting membrane potential (-55 mV/-60 mV. However, in vivo the availability of I(Na could potentially increase to >60% during inhibitory postsynaptic potential activity, which transiently hyperpolarize IHCs down to as far as -70 mV. When IHCs were held at -60 mV and I(Na elicited using a simulated action potential as a voltage command, we found that I(Na contributed to the subthreshold depolarization and upstroke of an action potential. We also found that I(Na is likely to be carried by the TTX-sensitive channel subunits Na(V1.1 and Na(V1.6 in both apical and basal IHCs. The results provide insight into how the biophysical properties of I(Na in mammalian cochlear IHCs could contribute to the spontaneous physiological activity during cochlear maturation in vivo.

  13. EHD4 and CDH23 Are Interacting Partners in Cochlear Hair Cells*

    OpenAIRE

    Sengupta, Soma; George, Manju; Miller, Katharine K.; Naik, Khurram; Chou, Jonathan; Cheatham, Mary Ann; Dallos, Peter; Naramura, Mayumi; Band, Hamid; Zheng, Jing

    2009-01-01

    Cadherin 23 (CDH23), a transmembrane protein localized near the tips of hair cell stereocilia in the mammalian inner ear, is important for delivering mechanical signals to the mechano-electric transducer channels. To identify CDH23-interacting proteins, a membrane-based yeast two-hybrid screen of an outer hair cell (OHC) cDNA library was performed. EHD4, a member of the C-terminal EH domain containing a protein family involved in endocytic recycling, was identified as a potential interactor. ...

  14. The effects of Tmc1 Beethoven mutation on mechanotransducer channel function in cochlear hair cells.

    Science.gov (United States)

    Beurg, Maryline; Goldring, Adam C; Fettiplace, Robert

    2015-09-01

    Sound stimuli are converted into electrical signals via gating of mechano-electrical transducer (MT) channels in the hair cell stereociliary bundle. The molecular composition of the MT channel is still not fully established, although transmembrane channel-like protein isoform 1 (TMC1) may be one component. We found that in outer hair cells of Beethoven mice containing a M412K point mutation in TMC1, MT channels had a similar unitary conductance to that of wild-type channels but a reduced selectivity for Ca(2+). The Ca(2+)-dependent adaptation that adjusts the operating range of the channel was also impaired in Beethoven mutants, with reduced shifts in the relationship between MT current and hair bundle displacement for adapting steps or after lowering extracellular Ca(2+); these effects may be attributed to the channel's reduced Ca(2+) permeability. Moreover, the density of stereociliary CaATPase pumps for Ca(2+) extrusion was decreased in the mutant. The results suggest that a major component of channel adaptation is regulated by changes in intracellular Ca(2+). Consistent with this idea, the adaptive shift in the current-displacement relationship when hair bundles were bathed in endolymph-like Ca(2+) saline was usually abolished by raising the intracellular Ca(2+) concentration.

  15. In vitro organotin administration alters guinea pig cochlear outer hair cell shape and viability.

    Science.gov (United States)

    Clerici, W J; Chertoff, M E; Brownell, W E; Fechter, L D

    1993-06-01

    Trimethyltin (TMT) and triethyltin (TET) disrupt auditory function at doses far below those shown to be neurotoxic. In vivo studies suggest that the initial effect of TMT on hearing occurs at the inner hair cell/spiral ganglion cell synapse, while later, the outer hair cell (OHC) undergoes structural and functional damage. TET produces acute effects upon afferent neurotransmission similar to those observed following TMT, but TET's effects on OHC structure and function have not been examined. OHCs are motile elements within the cochlea, believed to modulate the sensitivity and tuning within the inner ear. Changes in OHC length may alter hearing function, and length changes have been reported following exposure to various ototoxic agents in vitro. In the present study, 77 OHCs from 45 pigmented male guinea pigs were isolated in primary culture and exposed for 90 min to concentrations between 30 microM and 1.0 mM of TMT or TET and then to bathing medium for 30 min to remove the toxicant. Significant shortening of the OHC cell body occurred at all doses to both organotins, with a mean reduction in length of 15.1 and 20.2% for 1.0 mM TMT and TET, respectively, at the end of testing; control cells were only 3.4% shorter at the end of 90 min of perfusion with bathing medium. The effect of organotin exposure on OHC volume was not consistently related to either TMT or TET concentration or altered cell length. In addition, disruption of the plasma membrane characterized by bleb formation, the forceful ejection of cytoplasm, or bursting was seen in 80% of cells exposed to 1.0 mM TET, although not TMT; lower concentrations of both organotins disrupted the cell membrane in 10-30% of cells. Membrane rupture was not reliably associated with either increased cell volume or decreased length, implicating a weakening of the plasma membrane or cortical lattice as the basis for this effect. Consistent with the irreversible structural weakening of the lateral wall, resorption of

  16. Quantitative analysis of the ribbon synapse number of cochlear inner hair cells in C57BL/6J mice using the three-dimensional modeling method

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In mammals,the ribbon synapses of cochlear inner hair cells are a synaptic structure of the first sensory nerve in the pathway of acoustical signal transmission to the acoustic center,and it is directly involved in voice coding and neurotransmitter release. It is difficult to quantitatively analyze the ribbon synaptic number only using an electron microscope,because the ribbon synaptic number is relatively limited and their location is deep. In this study,the specific presynaptic structure-RIBEYE,and non-specific postsynaptic structure-GluR 2 & 3 in C57BL/6J mouse basilar membrane samples were treated by immunofluorescent labeling. Serial section was performed on the samples using a laser scanning confocal microscope,and then the serial sections were used to build three-dimensional models using 3DS MAX software. Each fluorescein color pair indicates one synapse,so the number of ribbon synapses of inner hair cells is obtained. The spatial distribution and the number of ribbon synapses of cochlear inner hair cells were clearly shown in this experiment,and the mean number of ribbon synapses per inner hair cell was 16.10±1.03. Our results have demonstrated the number of ribbon synapses is accurately calculated by double immunofluorescent labeling to presynaptic and postsynaptic structures,serial sections obtained using a laser scanning confocal microscope,and three-dimensional modeling obtained using 3DS MAX software. The method above is feasible and has important significance for further exploring the mechanism of sensorineural deafness.

  17. Otoferlin couples to clathrin-mediated endocytosis in mature cochlear inner hair cells.

    Science.gov (United States)

    Duncker, Susanne V; Franz, Christoph; Kuhn, Stephanie; Schulte, Uwe; Campanelli, Dario; Brandt, Niels; Hirt, Bernhard; Fakler, Bernd; Blin, Nikolaus; Ruth, Peter; Engel, Jutta; Marcotti, Walter; Zimmermann, Ulrike; Knipper, Marlies

    2013-05-29

    The encoding of auditory information with indefatigable precision requires efficient resupply of vesicles at inner hair cell (IHC) ribbon synapses. Otoferlin, a transmembrane protein responsible for deafness in DFNB9 families, has been postulated to act as a calcium sensor for exocytosis as well as to be involved in rapid vesicle replenishment of IHCs. However, the molecular basis of vesicle recycling in IHCs is largely unknown. In the present study, we used high-resolution liquid chromatography coupled with mass spectrometry to copurify otoferlin interaction partners in the mammalian cochlea. We identified multiple subunits of the adaptor protein complex AP-2 (CLAP), an essential component of clathrin-mediated endocytosis, as binding partners of otoferlin in rats and mice. The interaction between otoferlin and AP-2 was confirmed by coimmunoprecipitation. We also found that AP-2 interacts with myosin VI, another otoferlin binding partner important for clathrin-mediated endocytosis (CME). The expression of AP-2 in IHCs was verified by reverse transcription PCR. Confocal microscopy experiments revealed that the expression of AP-2 and its colocalization with otoferlin is confined to mature IHCs. When CME was inhibited by blocking dynamin action, real-time changes in membrane capacitance showed impaired synaptic vesicle replenishment in mature but not immature IHCs. We suggest that an otoferlin-AP-2 interaction drives Ca(2+)- and stimulus-dependent compensating CME in mature IHCs.

  18. Prestin-driven cochlear amplification is not limited by the outer hair cell membrane time constant.

    Science.gov (United States)

    Johnson, Stuart L; Beurg, Maryline; Marcotti, Walter; Fettiplace, Robert

    2011-06-23

    Outer hair cells (OHCs) provide amplification in the mammalian cochlea using somatic force generation underpinned by voltage-dependent conformational changes of the motor protein prestin. However, prestin must be gated by changes in membrane potential on a cycle-by-cycle basis and the periodic component of the receptor potential may be greatly attenuated by low-pass filtering due to the OHC time constant (τ(m)), questioning the functional relevance of this mechanism. Here, we measured τ(m) from OHCs with a range of characteristic frequencies (CF) and found that, at physiological endolymphatic calcium concentrations, approximately half of the mechanotransducer (MT) channels are opened at rest, depolarizing the membrane potential to near -40 mV. The depolarized resting potential activates a voltage-dependent K+ conductance, thus minimizing τ(m) and expanding the membrane filter so there is little receptor potential attenuation at the cell's CF. These data suggest that minimal τ(m) filtering in vivo ensures optimal activation of prestin.

  19. In Vivo Cochlear Hair Cell Generation and Survival by Coactivation of β-Catenin and Atoh1

    Science.gov (United States)

    Kuo, Bryan R.; Baldwin, Emily M.; Layman, Wanda S.; Taketo, Makoto Mark

    2015-01-01

    The mammalian cochlea exhibit minimal spontaneous regeneration, and loss of sensory hair cells (HCs) results in permanent hearing loss. In nonmammalian vertebrates, spontaneous HC regeneration occurs through both proliferation and differentiation of surrounding supporting cells (SCs). HC regeneration in postnatal mammalian cochleae in vivo remains limited by the small HC number and subsequent death of regenerated HCs. Here, we describe in vivo generation of 10-fold more new HCs in the mouse cochlea than previously reported, most of which survive to adulthood. We achieved this by combining the expression of a constitutively active form of β-catenin (a canonical Wnt activator) with ectopic expression of Atoh1 (a HC fate determination factor) in neonatal Lgr5+ cells (the presumed SC and HC progenitors of the postnatal mouse cochlea), and discovered synergistic increases in proliferation and differentiation. The new HCs were predominantly located near the endogenous inner HCs, expressed early HC differentiation markers, and were innervated despite incomplete alignment of presynaptic and postsynaptic markers. Surprisingly, genetic tracing revealed that only a subset of Lgr5+ cells that lie medial to the inner HCs respond to this combination, highlighting a previously unknown heterogeneity that exists among Lgr5+ cells. Together, our data indicate that β-catenin and Atoh1 mediate synergistic effects on both proliferation and differentiation of a subset of neonatal cochlear Lgr5+ cells, thus overcoming major limitations of HC regeneration in postnatal mouse cochleae in vivo. These results provide a basis for combinatorial therapeutics for hearing restoration. SIGNIFICANCE STATEMENT Hearing loss in humans from aging, noise exposure, or ototoxic drugs (i.e., cisplatin or some antibiotics) is permanent and affects every segments of the population, worldwide. However, birds, frog, and fish have the ability to recover hearing, and recent studies have focused on understanding

  20. TRPC-like conductance mediates restoration of intracellular Ca2+ in cochlear outer hair cells in the guinea pig and rat.

    Science.gov (United States)

    Raybould, Nicholas P; Jagger, Daniel J; Kanjhan, Refik; Greenwood, Denise; Laslo, Peter; Hoya, Noriyuki; Soeller, Christian; Cannell, Mark B; Housley, Gary D

    2007-02-15

    Ca2+ signalling is central to cochlear sensory hair cell physiology through its influence on sound transduction, membrane filter properties and neurotransmission. However, the mechanism for establishing Ca2+ homeostasis in these cells remains unresolved. Canonical transient receptor potential (TRPC) Ca2+ entry channels provide an important pathway for maintaining intracellular Ca2+ levels. TRPC3 subunit expression was detected in guinea pig and rat organ of Corti by RT-PCR, and localized to the sensory and neural poles of the inner and outer hair cells (OHCs) by confocal immunofluorescence imaging. A cation entry current with a TRPC-like phenotype was identified in guinea pig and rat OHCs by whole-cell voltage clamp. This slowly activating current was induced by the lowering of cytosolic Ca2+ levels ([Ca2+]i) following a period in nominally Ca2+-free solution. Activation was dependent upon the [Ca2+]o and was sustained until [Ca(2+)]i was restored. Ca2+ entry was confirmed by confocal fluorescence imaging, and rapidly recruited secondary charybdotoxin- and apamin-sensitive K(Ca) currents. Dual activation by the G protein-coupled receptor (GPCR)-phospholipase C-diacylglycerol (DAG) second messenger pathway was confirmed using the analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG). Ion substitution experiments showed that the putative TRPC Ca2+ entry current was selective for Na+ > K+ with a ratio of 1: 0.6. The Ca2+ entry current was inhibited by the TRPC channel blocker 2-aminoethyl diphenylborate (2APB) and the tyrosine kinase inhibitor, erbstatin analogue. We conclude that TRPC Ca2+ entry channels, most likely incorporating TRPC3 subunits, support cochlear hair cell Ca2+ homeostasis and GPCR signalling.

  1. Pseudo-immortalization of postnatal cochlear progenitor cells yields a scalable cell line capable of transcriptionally regulating mature hair cell genes.

    Science.gov (United States)

    Walters, Brandon J; Diao, Shiyong; Zheng, Fei; Walters, Bradley J; Layman, Wanda S; Zuo, Jian

    2015-12-07

    The mammalian cochlea is a highly specialized organ within the inner ear. Sensory hair cells (HC) in the cochlea detect and transduce sound waves into electrical impulses that are sent to the brain. Studies of the molecular pathways regulating HC formation are hindered by the very sparse nature of HCs, where only ~3300 are found within an entire mouse cochlea. Current cell lines mimic certain aspects of HCs but lack terminal HC marker expression. Here we successfully "pseudo-immortalized" cochlear progenitor cells using the "conditional reprogramming" technique. These cells, termed "Conditionally Reprogrammed Otic Stem Cells" (CR-OSC), are able to bypass the senescence inherent to cochlear progenitor cells without genetic alterations, allowing for the generation of over 15 million cells from a single cochlea. These cells can be differentiated and up-regulate both early and terminal differentiation genes associated with HCs, including the terminal HC differentiation marker prestin. CR-OSCs also respond to known HC cues, including upregulation of HC genes in response to Atoh1 overexpression, and upregulation of prestin expression after thyroid hormone application. Overall, we describe the creation of a HC line capable of regulated expression of HC genes that can easily be recreated in any laboratory from any mouse of interest.

  2. Cotransfection of Pax2 and Math1 promote in situ cochlear hair cell regeneration after neomycin insult.

    Science.gov (United States)

    Chen, Yan; Yu, Huiqian; Zhang, Yanping; Li, Wen; Lu, Na; Ni, Wenli; He, Yingzi; Li, Jin; Sun, Shan; Wang, Zhengmin; Li, Huawei

    2013-10-21

    The ideal strategy for hair cell regeneration is promoting residual supporting cell proliferation followed by induction of hair cell differentiation. In this study, cultured neonatal mouse organs of Corti were treated with neomycin to eliminate hair cells followed by incubation with recombined adenovirus expressing Pax2 and/or Math1. Results showed that overexpression of Pax2 significantly promoted proliferation of supporting cells. The number of BrdU⁺/myosin VIIA⁺ cells increased significantly in hair cell pre-existing region two weeks after adenovirus infection in Ad-Pax2-IRES-Math1 group compared to Ad-Pax2 and Ad-Math1 groups. This indicated that cotransfection of Pax2 and Math1 induced supporting cells to proliferate and differentiate into hair cells in situ. Most new hair cells were labeled by FM1-43 suggesting they acquired certain function. The results also suggest that inducing proliferating cells rather than quiescent cells to differentiate into hair cells by forced expression of Math1 is feasible for mammalian hair cell regeneration.

  3. Ephrin-A5/EphA4 signalling controls specific afferent targeting to cochlear hair cells.

    Science.gov (United States)

    Defourny, Jean; Poirrier, Anne-Lise; Lallemend, François; Mateo Sánchez, Susana; Neef, Jakob; Vanderhaeghen, Pierre; Soriano, Eduardo; Peuckert, Christiane; Kullander, Klas; Fritzsch, Bernd; Nguyen, Laurent; Moonen, Gustave; Moser, Tobias; Malgrange, Brigitte

    2013-01-01

    Hearing requires an optimal afferent innervation of sensory hair cells by spiral ganglion neurons in the cochlea. Here we report that complementary expression of ephrin-A5 in hair cells and EphA4 receptor among spiral ganglion neuron populations controls the targeting of type I and type II afferent fibres to inner and outer hair cells, respectively. In the absence of ephrin-A5 or EphA4 forward signalling, a subset of type I projections aberrantly overshoot the inner hair cell layer and invade the outer hair cell area. Lack of type I afferent synapses impairs neurotransmission from inner hair cells to the auditory nerve. By contrast, radial shift of type I projections coincides with a gain of presynaptic ribbons that could enhance the afferent signalling from outer hair cells. Ephexin-1, cofilin and myosin light chain kinase act downstream of EphA4 to induce type I spiral ganglion neuron growth cone collapse. Our findings constitute the first identification of an Eph/ephrin-mediated mutual repulsion mechanism responsible for specific sorting of auditory projections in the cochlea.

  4. Cochlear Gene Therapy

    OpenAIRE

    2012-01-01

    The purpose of this review is to highlight recent advances in cochlear gene therapy over the past several years. Cochlear gene therapy has undergone tremendous advances over the past decade. Beginning with some groundbreaking work in 2005 documenting hair cell regeneration using virallymediated delivery of the mouse atonal 1 gene, gene therapy is now being explored as a possible treatment for a variety of causes of hearing loss.

  5. COCHLEAR IMPLANTATION: MY EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Shankar

    2015-12-01

    Full Text Available Cochlear implant is a small, surgically implanted complex electronic device that can help to provide a sense of sound to a person with severe to profound sensorineural hearing loss. This type of hearing loss, typically involves damage to hair cells in the cochlea, as a result sound cannot reach the auditory nerve which usually receives information from hair cells. A cochlear implant skips the damaged hair cells and to stimulate the auditory nerve directly. An implant does not restore normal hearing, instead it can give a deaf person a useful representation of sounds in the environment and help him or her to understand speech. I am here presenting this article in relation to the indications, intraoperative and postoperative complications of cochlear implantation in our institute since January 2013. Children who receive implants at earlier age, outperform their peers who are implanted at a later age. This is reflected in all the areas of speech and language development.

  6. Frequency-dependent properties of a fluid jet stimulus : Calibration, modeling, and application to cochlear hair cell bundles

    NARCIS (Netherlands)

    Dinklo, Theo; Meulenberg, Cecil J. W.; van Netten, Sietse M.

    2007-01-01

    The investigation of small physiological mechanosensory systems, such as hair cells or their accessory structures in the inner ear or lateral line organ, requires mechanical stimulus equipment that allows spatial manipulation with micrometer precision and stimulation with amplitudes down to the nano

  7. Cochlear bionic acoustic metamaterials

    Science.gov (United States)

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  8. Mild maternal iron deficiency anemia induces DPOAE suppression and cochlear hair cell apoptosis by caspase activation in young guinea pigs.

    Science.gov (United States)

    Yu, Fei; Hao, Shuai; Zhao, Yue; Ren, Yahao; Yang, Jun; Sun, Xiance; Chen, Jie

    2014-01-01

    Iron deficiency (ID) anemia (IDA) alters auditory neural normal development in the mammalian cochlea. Previous results suggest that mild maternal IDA during pregnancy and lactation altered the hearing and nervous system development of the young offspring, but the mechanisms underlying the association are incompletely understood. The objective of this study was to evaluate the role of apoptosis in the development of sensory hair cells following mild maternal IDA during pregnancy and lactation. We established a maternal anemia model in female guinea pigs by using a mild iron deficient diet. The offspring were weaned on postnatal day (PND) 9 and then was given the iron sufficient diet. Maternal blood samples were collected on gestational day (GD) 21, GD 42, GD 63 and PND 9, serum level of iron (SI) or hemoglobin (Hb) was measured. Blood samples of pups were collected on PND 9 for SI measurement. On PND 24, pups were examined the distortion product otoacoustic emission (DPOAE) task, and then the cochleae were harvested for assessment of apoptosis by immunohistochemistry of cysteine-aspartic acid proteases 3/9 (caspase-3/9) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay, and by double immunofluorescence for the colocalization of TUNEL and caspase-3. Blood samples of pups were collected on PND 24 for SI and Hb measurements. Here we show that mild maternal IDA during pregnancy and lactation resulted in hearing impairment, decreased hair cell number, caspase-3/9 activation and increased apoptotic cell number of young guinea pigs. These results indicate a key role for apoptosis in inhibition of hair cell development, caused by mild maternal IDA during pregnancy and lactation.

  9. Development and Function of the Voltage-Gated Sodium Current in Immature Mammalian Cochlear Inner Hair Cells

    OpenAIRE

    Eckrich, T.; Varakina, K.; Johnson, S. L.; Franz, C; Singer, W.; Kuhn, S; Knipper, M; Holley, M.C.; Marcotti, W.

    2012-01-01

    Inner hair cells (IHCs), the primary sensory receptors of the mammalian cochlea, fire spontaneous Ca(2+) action potentials before the onset of hearing. Although this firing activity is mainly sustained by a depolarizing L-type (Ca(V)1.3) Ca(2+) current (I(Ca)), IHCs also transiently express a large Na(+) current (I(Na)). We aimed to investigate the specific contribution of I(Na) to the action potentials, the nature of the channels carrying the current and whether the biophysical properties of...

  10. 顺铂体内注射对子代豚鼠耳蜗毛细胞的影响%Effect of cisplatin - injected on cochlear hair ceus in newborn guinea pigs

    Institute of Scientific and Technical Information of China (English)

    郝帅; 闫艾慧; 姜学钧

    2011-01-01

    [目的]了解孕晚期顺铂暴露是否会诱导子代豚鼠耳蜗毛细胞损伤.[方法]将孕晚期豚鼠12只随机分为两组,在孕50 d至56 d,顺铂组经腹膜腔注射顺铂1,5mg/kg·d,对照组注射生理盐水1.5 mg/kg·d.出生后14d,应用原位末端转移酶标记技术(TUNEL)和Caspase-3免疫组化染色检测毛细胞凋亡情况.[结果]孕晚期顺铂暴露的子代豚鼠耳蜗毛细胞有凋亡发生及Caspase -3蛋白表达.[结论]孕期顺铂暴露可诱导子代豚鼠耳蜗毛细胞Caspase -3表达及凋亡发生.%[Objective] To evaluate the role of pregnant cisplatin exposure in inducing apoptosis on the development of cochlear in newborn guinea pigs. [ Methods] On gestational day 50 to 56,pregnant guinea pigs were intraperitoneally injected with 1.5 mg/kg body weight cisplatin and normal saline once a day,respectively. On postnatal day 14,the temporal bones of guinea pig pups were removed, immunohistochemistry was used for detecting the expression of caspase -3 and TUNEL method for hair cell apoptosis. [ Results] Apoptosis and caspase - 3 expression were observed in cochlear hair cells of newbom guinea pigs with pregnant cisplatin exposure. [Conclusion] Perinatal cispiatin exposure would induce cochlear hair cell apoptosis.

  11. 突触内吞关键蛋白Dynamin在小鼠耳蜗内毛细胞中的表达研究%Study on the Expression of Synaptic Endocytosis Key Protein Dynamin in Mice Cochlear Inner Hair Cells

    Institute of Scientific and Technical Information of China (English)

    蔡婷; 袁伟

    2014-01-01

    目的:研究生理情况下Dynamin各亚型在小鼠耳蜗内毛细胞(IHC)的表达分布特点,为探讨其在毛细胞内可能发挥的生理功能以及与听信号传导的关系做铺垫。方法取成年小鼠耳蜗基底膜行免疫荧光染色,激光共聚焦显微镜观察Dynamin各亚型表达及定位分布情况。结果Dynamin各亚型在小鼠耳蜗内毛细胞中均有表达。其中,Dyna⁃min-1表达于整个内毛细胞内,Dynamin-2点状分布在内毛细胞胞质,Dynamin-3高表达于内毛细胞核下近螺旋神经节区域。结论网格蛋白介导内吞过程是毛细胞内吞作用的重要机制,作为该过程中的关键蛋白,Dynamin各亚型在耳蜗内毛细胞中均有表达,提示Dynamin在内毛细胞中可能发挥着重要的生理功能。%Objective To study expression and distribution characteristics of each subtype of Dynamin in mice inner hair cell (IHC) and its possible roles in the physiological function of inner hair cells as well as laying the groundwork for study⁃ing its relationship with hearing. Methods Expression and distribution of each subtype of Dynamin in cochlear basement mem⁃brane of adult mice were distinguished by immunefluorescent, and examined by laser confocal microscope. Results Various subtypes of Dynamin were detected in the inner hair cell of mice. Of which, Dynamin-1 was seen in the entire inner hair cell, Dnamin-2 in the cytoplasm, and Dynamin-3 highly expressed under the nucleus of inner hair cells close to the spiral ganglion. Conclusion Clathrin mediated endocytosis is a major pathway of vesicle recycling, in which, Dynamin plays an important role. Various subtypes of Dynamin are expressed in the cochlear hair cells, indicating that Dynamin may have an important physio⁃logical function in inner hair cells.

  12. 丁胺卡那霉素对豚鼠耳蜗毛细胞凋亡及听力阈值的影响%Effect of amikacin on the cochlear hair cells and hearing threshold ofguinea pigs

    Institute of Scientific and Technical Information of China (English)

    巴云鹏; 董明敏

    2000-01-01

    Aifr: To investigate the cochlear hair cell apoptosis induced by the ototoxic aminoglycoside antibiotic amikacinand the effect of hair cell apoptosis on heating loss in guinea pigs. Methods: Fifteen guinea pigs were randomly divided into 3groups, which had been intramuscularly injected with amikacin for 1 day, 3 days and 6 days respectively before they were put todeath. Auditory brainstem response (ABR) and the apoptosis of cochlea hair cells were examined with TdT-modided biotin-dUTPNick-end labeling( TUNEL) at different times. Results: ①In normal cochlear hair cells, no apoptic cell were generally noted. In3 groups the morphological changes of the cell apoptosis were noted at 1,3 and 6 days after injection with amikacin; ②ABRthreshold had no obvious changes 1,3 days after using amikacin while an elevation of ABR threshold was noted after using amikacinfor 6 successive days in guinea pigs. C orclusion: ① Amikacin can induce the apoptosis of the cochlear hair cells in guinea pigs.Cell apoptosis was a mode of hair cell loss after injection with amikacin in guinea pigs. ② The ototoxin mechanism of the amino-glycoside antibiotic may be related to apoptosis of the cochlear hair cell induced by itself.%目的:探讨丁胺卡那霉素作用于耳蜗系统时毛细胞凋亡现象及其在听力损伤中的作用。方法:15只豚鼠随机分为3组,各组肌内注射丁胺卡那霉素400mg·kg-1·d-1,分别于用药1 d,3 d,6 d后处死。处死前检测其听脑于反应(auditory brainstem responses,ABR)的变化,并利用光镜和TUNEL标记技术检测耳蜗毛细胞发生凋亡的情况。结果:①豚鼠肌内注射丁胺卡那霉素1 d后耳蜗毛细胞即出现凋亡现象,连续用药3~6 d,毛细胞凋亡呈强阳性表达;②耳蜗毛细胞凋亡出现的早期豚鼠听力阈值无明显改变,连续用药6 d后听力阈值则明显提高。结论:①丁胺卡那霉素作用于耳蜗毛细胞可引起毛细胞凋亡,细胞

  13. The Fate of the Spiral Ganglion Cells After the Cochlear Hair Cells Serious Injuried%耳蜗毛细胞严重缺失后螺旋神经节细胞的病理变化

    Institute of Scientific and Technical Information of China (English)

    王建军; 毛华杰; 董吕华; 翟所强; 马龙

    2013-01-01

    Objective To study morphological changes of spiral ganglion cells (SGN) following severe cochlear hair cells injury. Methods Guinea pigs were given kanamycin sulfate (1000 mg/kg) intramuscularly followed by furosemide (100 mg/kg) intravenously 2 hours later. Auditory brainstem responses (ABRs) and cochlear morphology were examined at 3 days, 7 days, 1 month and 2 months respectively after the treatment. Results ABR thresholds were greatly elevated after the treatment, with no significant difference among the different time groups. Scanning electron microscopy revealed severe damage to cochlear hair cells, especially out hair cells (OHC) after 7 days. There was also extensive loss of inner hair cells in animals with severe auditory function damage while supporting cells in the organ of Corti were preserved. The SGN showed no change on Day 7, al-though severe SGN loss was seen after 1 month, with total collapse of the organ of Corti. Conclusion Drug-induced hearing loss starts with hair cell loss, followed by SGN loss. In addition, the extent of SGN damage seems to correlate to time lapse after drug administration and can take years to develop, which may provide a time window for cochlear implant.%目的:观察耳蜗毛细胞严重损伤后螺旋神经节细胞的病变过程。方法豚鼠肌肉注射硫酸卡那霉素(1000mg/kg)2小时后给予速尿(100mg/kg)静脉注射,分别于用药3天、7天、1月及2月行听觉脑干诱发电位(auditory brainstem response ABR)及耳蜗形态学检测。结果联合应用速尿和硫酸卡那霉素后,豚鼠鼠ABR阈值出现很大程度提高,给药3天、7天、1月、2个月组各频率ABR阈值比较无差别;对药物损伤致聋豚鼠进行耳蜗切片、扫描电镜观察,发现用药7天后耳蜗毛细胞严重受损,以外毛细胞(OHCs)缺失为主,严重致聋的豚鼠内毛细胞(IHCs)也广泛缺失,但是切片显示柯替氏器的支持细胞存在;螺旋神

  14. 庆大霉素中毒后豚鼠耳蜗毛细胞的再生%Regeneration of cochlear hair cells of guinea pigs following gentamicin ototoxicity

    Institute of Scientific and Technical Information of China (English)

    倪月秋; 汤浩; 崔城

    2006-01-01

    状突出物减少;停药后30 d豚鼠耳蜗第二转外毛细胞静纤毛融合、缺失、倒伏等病理改变,明显弱于庆大霉素停药1 d和3 d,同时耳蜗第三转有新生的静纤毛出现.结论:庆大霉素耳中毒后豚鼠耳蜗毛细胞损伤后存活30 d者其耳蜗毛细胞形态上有所恢复,且听性脑干反应阈值也有一定程度的恢复,说明庆大霉素耳中毒后豚鼠耳蜗毛细胞具有再生修复能力.庆大霉素损伤后的毛细胞可以再生.%BACKGROUND: Formerly, it was thought that the damaged hair cells could not have the repair ability. Recent studies demonstrate that mammal vestibule hair cells also possess certain repair ability after being destroyed.Then, whether mammalia animal cochlea hair cells possess regenerative ability after being destroyed is disputed.OBJECTIVE: To observe cochlear hair cells condition and threshold value change of auditory brainstem response (ABR) at different time following gentamicin ototoxicity by using scanning electron microscope (SEM) technique combined with ABR test, so as to investigate whether cochlear hair cells of mammals can be regenerated after being injured.DESIGN: A randomized and controlled animal experiment.SETTING: Department of Physiology, Shenyang Medical College.MATERIALS: This experiment was carried out at the Hearing Research Room of China Medical University from November 2001 to May 2002. Totally 60 healthy adult white Guinea pigs, with red eyes and sensitive auricle reflex, of clean degree, were used and randomly divided into gentamicin group and normal control group with 30 guinea pigs in each one.METHODS: 100 mg/kg gentamicin was intraperitoneally daily injected into the guinea pigs, serving as gentamicin group. Same volume of normal saline (2.5 mL/kg) was intraperitoneally daily injected into the guinea pigs,serving as normal control group. All the guinea pigs were given medication for 10 successive days. Threshold value of ABR was detected respectively pre-operatively and at the 1st, 3

  15. The Effects of Cisplatin on the Expression of Calpain in Mouse Cochlear Hair Cell in Vitro%顺铂对离体培养小鼠耳蜗毛细胞钙蛋白酶表达的影响

    Institute of Scientific and Technical Information of China (English)

    张立伟; 刘芳芳; 于利; 王爱梅

    2016-01-01

    Objective To investigate the effects of cisplatin on the expression of calpain in mouse cochlear hair cells in vitro ,and to explore the mechanism of cisplatin-induced apoptosis in mouse cochlear hair cells .Meth‐ods A total of 600 cochlear basilar membranes isolated from Kunming mice at postnatal day 3 were cultured for 24 hours ,then randomly divided into control group and 3 cisplatin groups (4 μg/ml ,8 μg/ml and 16 μg/ml) .Each group contained 150 basilar membranes .Four groups were continually cultured for another 24 hours .Hoechst 33258 staining was used to detect the apoptosis of cochlear hair cell .Immunofluorescent staining and Western blot were carried out for detecting the expressions of calpain 1 (μ-calpain) and calpain 2 (m-calpain) in mouse cochlear hair cells .Results The percent of apoptotic hair cells in the three cisplatin groups (15 .63% ± 0 .20% ,38 .40% ± 2 .64% and 64 .24% ± 0 .05% ,respectively) was greater than that of in the control group (5 .55% ± 0 .12% ) , showing a clear dose-response relationship (P<0 .01) .Furthermore ,the expressions of μ -calpain and m -cal‐pain in different cisplatin groups were increased ,and m -calpain expression was great remarkably with increased concentration of cisplatin (P<0 .01) .Conclusion Our results suggest that cisplatin can induce the apoptosis in mouse cochlear hair cells by regulating calpain pathway .This may play a role in the cisplatin-induced ototoxicity .%目的:观察顺铂对离体培养小鼠耳蜗毛细胞钙蛋白酶(calpain )表达的影响,探讨顺铂致耳蜗毛细胞凋亡的机制。方法取出生后3 d的昆明小鼠300只(600耳),分离出耳蜗基底膜600条,体外培养24 h后,随机分为对照组和4、8、16μg/ml顺铂组,每组150条;对照组加入2ml新鲜培养基,顺铂组分别加入2 ml含不同浓度顺铂(4、8、16μg/ml)的新鲜培养基,再继续培养24 h后,应用Hoechst 33258荧光染色观察耳蜗毛细胞

  16. Modelling Cochlear Mechanics

    Directory of Open Access Journals (Sweden)

    Guangjian Ni

    2014-01-01

    Full Text Available The cochlea plays a crucial role in mammal hearing. The basic function of the cochlea is to map sounds of different frequencies onto corresponding characteristic positions on the basilar membrane (BM. Sounds enter the fluid-filled cochlea and cause deflection of the BM due to pressure differences between the cochlear fluid chambers. These deflections travel along the cochlea, increasing in amplitude, until a frequency-dependent characteristic position and then decay away rapidly. The hair cells can detect these deflections and encode them as neural signals. Modelling the mechanics of the cochlea is of help in interpreting experimental observations and also can provide predictions of the results of experiments that cannot currently be performed due to technical limitations. This paper focuses on reviewing the numerical modelling of the mechanical and electrical processes in the cochlea, which include fluid coupling, micromechanics, the cochlear amplifier, nonlinearity, and electrical coupling.

  17. ATP hydrolysis is critically required for function of CaV1.3 channels in cochlear inner hair cells via fueling Ca2+ clearance.

    Science.gov (United States)

    Weiler, Simon; Krinner, Stefanie; Wong, Aaron B; Moser, Tobias; Pangršič, Tina

    2014-05-14

    Sound encoding is mediated by Ca(2+) influx-evoked release of glutamate at the ribbon synapse of inner hair cells. Here we studied the role of ATP in this process focusing on Ca(2+) current through CaV1.3 channels and Ca(2+) homeostasis in mouse inner hair cells. Patch-clamp recordings and Ca(2+) imaging demonstrate that hydrolyzable ATP is essential to maintain synaptic Ca(2+) influx in inner hair cells via fueling Ca(2+)-ATPases to avoid an increase in cytosolic [Ca(2+)] and subsequent Ca(2+)/calmodulin-dependent inactivation of CaV1.3 channels.

  18. The study of cochlear outer hair cells function in normally hearing patients with tinnitus%听力正常的耳鸣患者的耳蜗外毛细胞功能研究

    Institute of Scientific and Technical Information of China (English)

    刁明芳; 孙建军; 田芳洁; 贾仲红; 刘阳; 陈东兰

    2012-01-01

    目的 用畸变产物耳声发射(distortion product evoked oto-acoustic emissions,DPOAE)检测听力正常耳鸣患者的耳蜗外毛细胞(outer hair cell,OHC)功能.方法 选取门诊50例听力正常(250~8000Hz)伴有耳鸣的患者,对照组选取年龄性别匹配的听力正常无耳鸣的志愿者.比较两组受试者的DPOAE幅值.结果 与对照组相比,耳鸣组DPOAE幅值降低,在高频(4~8kHz)的幅值差异有显著性(P<0.05).结论 DPOAE幅值下降与听力正常患者的耳鸣产生有关,耳蜗OHC功能受损可能是耳鸣的来源.%Objective To compare cochlear outer hair cells functionin normally hearing patients with and without tinnitus based on distortion product otoacoustic emission(DPOAE). Methods Fifty tinnitus patients with normal hearing in the frequency range between 250 to 8000 Hz were selected as a study group. The control group consisted of 50 otologically normal subjects who have normal hearing threshold levels without tinnitus and were selected to match the study group by age and gender. DPOAE-grams of tinnitus group were compared with theose of control group. Results Tinnitus ears exhibited relatively decrease amplitudes of DPOAE when compared with the group of healthy ears .Statistically significant (P< 0.05) decrease mean values of DPOAE amplitudes were observed at a frequency of 4-8kHz. Conclusions There is an association between tinnitus and reduced distortion product otoacoustic emission amplitudes. The reduced cochlear outer hair cells function may be the source of tinnitus.

  19. Hair cell regeneration or the expression of related factors that regulate the fate specification of supporting cells in the cochlear ducts of embryonic and posthatch chickens.

    Science.gov (United States)

    Jiang, Lingling; Jin, Ran; Xu, Jincao; Ji, Yubin; Zhang, Meiguang; Zhang, Xuebo; Zhang, Xinwen; Han, Zhongming; Zeng, Shaoju

    2016-02-01

    Hair cells in posthatch chickens regenerate spontaneously through mitosis or the transdifferentiation of supporting cells in response to antibiotic injury. However, how embryonic chicken cochleae respond to antibiotic treatment remains unknown. This study is the first to indicate that unlike hair cells in posthatch chickens, the auditory epithelium was free from antibiotic injury (25-250 mg gentamicin/kg) in embryonic chickens, although FITC-conjugated gentamicin actually reached embryonic hair cells. Next, we examined and counted the cells and performed labeling for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) (triple or double labeling) in the injured cochlea ducts after gentamicin treatment at 2 h (h), 15 h, 24 h, 2 days (d), 3 d and 7 d after BrdU treatment in posthatch chickens. Our results indicated that following gentamicin administration, proliferating cells (BrdU+) were labeled for Atoh1/Math1 in the damaged areas 3d after gentamicin administration, whereas hair cells (PV+) renewed through mitosis (BrdU+) or direct transdifferentiation (BrdU-) were evident only after 5 d of gentamicin administration. In addition, Sox2 expression was up-regulated in triggered supporting cells at an early stage of regeneration, but stopped at the advent of mature hair cells. Our study also indicated that p27(kip1) was expressed in both hair cells and supporting cells but was down-regulated in a subgroup of the supporting cells that gave rise to hair cells. These data and the obtained dynamic changes of the cells labeled for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) are useful for understanding supporting cell behaviors and their fate specification during hair cell regeneration.

  20. Multiple quantitative trait loci modify cochlear hair cell degeneration in the Beethoven (Tmc1Bth) mouse model of progressive hearing loss DFNA36.

    Science.gov (United States)

    Noguchi, Yoshihiro; Kurima, Kiyoto; Makishima, Tomoko; de Angelis, Martin Hrabé; Fuchs, Helmut; Frolenkov, Gregory; Kitamura, Ken; Griffith, Andrew J

    2006-08-01

    Dominant mutations of transmembrane channel-like gene 1 (TMC1) cause progressive sensorineural hearing loss in humans and Beethoven (Tmc1Bth/+) mice. Here we show that Tmc1Bth/+ mice on a C3HeB/FeJ strain background have selective degeneration of inner hair cells while outer hair cells remain structurally and functionally intact. Inner hair cells primarily function as afferent sensory cells, whereas outer hair cells are electromotile amplifiers of auditory stimuli that can be functionally assessed by distortion product otoacoustic emission (DPOAE) analysis. When C3H-Tmc1Bth/Bth is crossed with either C57BL/6J or DBA/2J wild-type mice, F1 hybrid Tmc1Bth/+ progeny have increased hearing loss associated with increased degeneration of outer hair cells and diminution of DPOAE amplitudes but no difference in degeneration of inner hair cells. We mapped at least one quantitative trait locus (QTL), Tmc1m1, for DPOAE amplitude on chromosome 2 in [(C/B)F1xC]N2-Tmc1Bth/+ backcross progeny, and three other QTL on chromosomes 11 (Tmc1m2), 12 (Tmc1m3), and 5 (Tmc1m4) in [(C/D)F1xC]N2-Tmc1Bth/+ progeny. The polygenic basis of outer hair cell degeneration in Beethoven mice provides a model system for the dissection of common, complex hearing loss phenotypes, such as presbycusis, that involve outer hair cell degeneration in humans.

  1. Hair cell-like cells generation induced by nature culture of cochlear sensory epithelia in rat%小鼠耳蜗感觉上皮细胞的自然培养诱导毛细胞的产生

    Institute of Scientific and Technical Information of China (English)

    刘晖; 李胜利; 朱宏亮; 姚小宝; 王晓侠

    2003-01-01

    Object To establish rat auditory epithelial cell culture and try to find precursor cells of auditory hair cells in vitro and apply them to study mammalian hair cell regeneration.Methods With refinement of culture media and techniques,cochlear sensory epithelial cells of rat were cultured.Immunocytochemistry and Bromodeoxyuridine(BrdU)labeling were used to detect properties and mitotic status of cultured cells.Results The cultured auditory epithelial cells showed a large,flat epithelial morphotype and expressed F-actin and cytokerafin,a subset of cells generated from auditory epithelium were labeled by calretinin, a specific marker of early hair cell.The appearance of calretinin-positive cells were also confirmed in 3rd passage culture by immunostaining.Conclusions Postnatal rat auditory epithelium can be induced to generate hair cell-like cells by nature culture,this phenomenon suggested thatprogenitor cells may exist in rat cochlea and they may give birth to new hair cells. Whether these progenitor cells are tissue specific stem cells was still need more study.%目的培养小鼠耳蜗上皮细胞,寻找听觉毛细胞的前体细胞,从而研究听觉毛细胞的再生.方法改良细胞培养基和培养技术,建立小鼠耳蜗听觉上皮细胞的培养;用免疫细胞化学方法和BrdU标记法检测培养细胞的性质和分裂状态.结果培养的听觉上皮细胞表现为大而扁平的上皮细胞形态,并且表达上皮细胞的标志F-actin和cytokeratin,部分新生的细胞可被早期毛细胞的特异标志calretinin着染,表明有听毛细胞样的细胞产生.这种现象经3次传代培养后仍然存在.结论自然细胞培养方法可能诱导小鼠听觉毛细胞的产生,在小鼠的耳蜗内可能存在听觉毛细胞的前体细胞,而这些前体细胞是否是组织特异性干细胞还需要更进一步的研究.

  2. Medial Cochlear Efferent Function: A Theoretical Analysis

    Science.gov (United States)

    Mountain, David C.

    2011-11-01

    Since the discovery of the cochlear efferent system, many hypotheses have been put forth for its function. These hypotheses for its function range from protecting the cochlea from over stimulation to improving the detection of sounds in noise. It is known that the medial efferent system innervates the outer hair cells and that stimulation of this system reduces basilar membrane and auditory nerve sensitivity which suggests that this system acts to decrease the gain of the cochlear amplifier. Here I present modeling results as well as analysis of published experimental data that suggest that the function of the medial efferent reflex is to decrease the cochlear amplifier gain by just the right amount so that the nonlinearity in the basilar membrane response lines up perfectly with the inner hair cell nonlinear transduction process to produce a hair cell receptor potential that is proportional to the logarithm of the sound pressure level.

  3. Cochlear Implants

    Science.gov (United States)

    A cochlear implant is a small, complex electronic device that can help to provide a sense of sound. People who are ... of-hearing can get help from them. The implant consists of two parts. One part sits on ...

  4. Effect of Electroacupuncture on Succinate Dehydrogenase of Gentamycin Induced Ototoxic Cochlear Hair Cells in Guinea Pigs%电针对庆大霉素耳中毒豚鼠耳蜗内琥珀酸脱氢酶的影响

    Institute of Scientific and Technical Information of China (English)

    陈乃秋; 康颂建; 曾兆麟; 史献君; 李亚鲁; 刘存

    2002-01-01

    Objective: To observe the effect of dectroacupuncture (EA) on succinate dehydrogenase (SDH) ofgentamycin (GE) induced ototoxic cochlear hair cells. Methods: Preyer's reflex normal guinea pigs were seldectedand randomized into three groups: GE group, EA group and control group. Brainstem auditory evoked potential(BAEP) and SDH in the cochlear hair cells were taken as indexes. In the animals of GE group GE was alone inject-ed intramuscularly 80 mg kg- 1. d- 1 for successive 20 days, while in the animals of EA group GE and additional EAwere applied once a day for 15 minutes each time on Tinggong (SI 19), Yifeng(SJ17) and Shenshu (LJB23)points.Results: In GE group BAEP reaction threshold rose markedly, while in EA group it rose slightly. The differencewas significant between the two groups ( P< 0.05 ). The change of SDH within cochlear hair cells and the degreeof hair cell lesion in the EA group were lower than those in GE group. Conclusions: EA therapy could relieve GEototoxicity, maintain SDH in cochlear hair cells, which might be a possible mechanism of action of EA.%目的观察电针对豚鼠庆大霉素(gentamicin,GE)耳中毒引起的耳蜗琥珀酸脱氢酶(succinate de-hydrogenase,SDH)变化的影响.方法将动物随机分成3组:GE组动物肌肉注射GE80 mg@kg-1.d-1,连续注射20天:针刺组肌肉注射GE同GE组,每天电针双侧听宫、翳风、肾俞穴1次,持续刺激15 min;对照组动物不做任何处理.以脑干听觉诱发电位(BAEP)、SDH组织化学检测为观察指标.结果对照组BAEP和SDH两项指标无明显变化;GE组BAEP反应阈明显升高,SDH显色变淡或消失,毛细胞受损显著;针刺组BAEP反应阈升高幅度和SDH变化及毛细胞损害程度均明显低于GE组.结论针刺组能减轻GE耳毒性,对SDH有保护作用.

  5. Deficiency of angulin-2/ILDR1, a tricellular tight junction-associated membrane protein, causes deafness with cochlear hair cell degeneration in mice.

    Science.gov (United States)

    Higashi, Tomohito; Katsuno, Tatsuya; Kitajiri, Shin-Ichiro; Furuse, Mikio

    2015-01-01

    Tricellular tight junctions seal the extracellular spaces of tricellular contacts, where the vertices of three epithelial cells meet, and are required for the establishment of a strong barrier function of the epithelial cellular sheet. Angulins and tricellulin are known as specific protein components of tricellular tight junctions, where angulins recruit tricellulin. Mutations in the genes encoding angulin-2/ILDR1 and tricellulin have been reported to cause human hereditary deafness DFNB42 and DFNB49, respectively. To investigate the pathogenesis of DFNB42, we analyzed mice with a targeted disruption of Ildr1, which encodes angulin-2/ILDR1. Ildr1 null mice exhibited profound deafness. Hair cells in the cochlea of Ildr1 null mice develop normally, but begin to degenerate by two weeks after birth. Tricellulin localization at tricellular contacts of the organ of Corti in the cochlea was retained in Ildr1 null mice, but its distribution along the depth of tricellular contacts was affected. Interestingly, compensatory tricellular contact localization of angulin-1/LSR was observed in the organ of Corti in Ildr1 null mice although it was hardly detected in the organ of Corti in wild-type mice. The onset of hair cell degeneration in Ildr1 null mice was earlier than that in the reported Tric mutant mice, which mimic one of the tricellulin mutations in DFNB49 deafness. These results indicate that the angulin-2/ILDR1 deficiency causes the postnatal degenerative loss of hair cells in the cochlea, leading to human deafness DFNB42. Our data also suggest that angulin family proteins have distinct functions in addition to their common roles of tricellulin recruitment and that the function of angulin-2/ILDR1 for hearing cannot be substituted by angulin-1/LSR.

  6. ILDR1 deficiency causes degeneration of cochlear outer hair cells and disrupts the structure of the organ of Corti: a mouse model for human DFNB42

    Directory of Open Access Journals (Sweden)

    Qing Sang

    2015-03-01

    Full Text Available Immunoglobulin-like domain containing receptor 1 (ILDR1 is a poorly characterized gene that was first identified in lymphoma cells. Mutations in ILDR1 are responsible for DFNB42, but the pathogenesis of hearing loss caused by ILDR1 mutations remains to be elucidated. To explore the role of ILDR1 in hearing, we created Ildr1 knockout mice. In heterozygous mice, ILDR1 expression was found in outer hair cells (OHCs and inner hair cells (IHCs of the organ of Corti. ILDR1-deficient mice are profoundly deaf by postnatal day 21 (P21. No significant difference was observed in the supporting cells and IHCs of ILDR1-deficient mice, but progressive degeneration of OHCs occurred at P15 and disruption of the tunnel running through the organ of Corti was noticeable at P21. By P28, there were no OHCs visible in any of the turns of the organ of Corti, and the tunnel of the organ of Corti was entirely destroyed. ILDR1 deficiency affects expression of tricellulin in vivo, and this provides a possible explanation to hearing loss. To further elucidate the mechanism of deafness related to ILDR1 deficiency, we pursued a differential proteomic approach to comprehensively assess differential protein expression in the cochleae of Ildr1+/− and Ildr1−/− mice at P21. Altogether, 708 proteins were up-regulated (fold change >1.5 and 114 proteins were down-regulated (fold change <0.5 in the Ildr1−/− mice compared with Ildr1+/− mice. Gene ontology classification indicated that a number of differentially expressed proteins are involved in cell adhesion, protein and vesicle-mediated transport, cell death, membrane organization, and cellular homeostasis. A few of these proteins are closely related to hearing development. Taken together, our data suggest that ILDR1 is important for the survival of OHCs and provide novel insights into the pathogenesis of human deafness DFNB42 deafness.

  7. Chronic Conductive Hearing Loss Leads to Cochlear Degeneration.

    Directory of Open Access Journals (Sweden)

    M Charles Liberman

    Full Text Available Synapses between cochlear nerve terminals and hair cells are the most vulnerable elements in the inner ear in both noise-induced and age-related hearing loss, and this neuropathy is exacerbated in the absence of efferent feedback from the olivocochlear bundle. If age-related loss is dominated by a lifetime of exposure to environmental sounds, reduction of acoustic drive to the inner ear might improve cochlear preservation throughout life. To test this, we removed the tympanic membrane unilaterally in one group of young adult mice, removed the olivocochlear bundle in another group and compared their cochlear function and innervation to age-matched controls one year later. Results showed that tympanic membrane removal, and the associated threshold elevation, was counterproductive: cochlear efferent innervation was dramatically reduced, especially the lateral olivocochlear terminals to the inner hair cell area, and there was a corresponding reduction in the number of cochlear nerve synapses. This loss led to a decrease in the amplitude of the suprathreshold cochlear neural responses. Similar results were seen in two cases with conductive hearing loss due to chronic otitis media. Outer hair cell death was increased only in ears lacking medial olivocochlear innervation following olivocochlear bundle cuts. Results suggest the novel ideas that 1 the olivocochlear efferent pathway has a dramatic use-dependent plasticity even in the adult ear and 2 a component of the lingering auditory processing disorder seen in humans after persistent middle-ear infections is cochlear in origin.

  8. Improved biolistic transfection of hair cells.

    Directory of Open Access Journals (Sweden)

    Hongyu Zhao

    Full Text Available Transient transfection of hair cells has proven challenging. Here we describe modifications to the Bio-Rad Helios Gene Gun that, along with an optimized protocol, improve transfection of bullfrog, chick, and mouse hair cells. The increased penetrating power afforded by our method allowed us to transfect mouse hair cells from the basal side, through the basilar membrane; this configuration protects hair bundles from damage during the procedure. We characterized the efficiency of transfection of mouse hair cells with fluorescently-tagged actin fusion protein using both the optimized procedure and a published procedure; while the efficiency of the two methods was similar, the morphology of transfected hair cells was improved with the new procedure. In addition, using the improved method, we were able to transfect hair cells in the bullfrog sacculus and chick cochlea for the first time. We used fluorescent-protein fusions of harmonin b (USH1C and PMCA2 (ATP2B2; plasma-membrane Ca(2+-ATPase isoform 2 to examine protein distribution in hair cells. While PMCA2-EGFP localization was similar to endogenous PMCA2 detected with antibodies, high levels of harmonin-EGFP were found at stereocilia tapers in bullfrog and chick, but not mouse; by contrast, harmonin-EGFP was concentrated in stereocilia tips in mouse hair cells.

  9. Current status and correlated issues on cochlear implantation

    Institute of Scientific and Technical Information of China (English)

    CAO Ke-li; WANG Lin-e

    2006-01-01

    @@ Cochlear implant is a biomedical device, which can directly stimulate the auditory nerve pass-by the damaged hair cell to recover and rebuild the hearing of deaf people. The implant can also stimulate the auditory brainstem and cortex in patients whose auditory nerve is not accessible because of acoustic tumors. Cochlear implantation can make the patients generate electrical hearing (artificial hearing).The artificial hearing can recover,improve or rebuild the hearing of deaf people through electrical stimulus.

  10. Hair Transplants

    Science.gov (United States)

    ... to Choose the Best Skin Care Products Hair Transplants What are hair transplants? In punch transplanting, a plug containing hair follicles ... should first be done before considering a hair transplant? Before the procedure, an ASDS doctor will review ...

  11. Oily hair

    Science.gov (United States)

    Hair - oily ... are some tips for preventing and treating oily hair: Shampoo your hair every day. Leaving the shampoo on your head ... minutes before rinsing may help. Avoid brushing your hair too often or too vigorously, since the brushing ...

  12. Gain and frequency tuning within the mouse cochlear apex

    Energy Technology Data Exchange (ETDEWEB)

    Oghalai, John S.; Raphael, Patrick D. [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Gao, Simon [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Department of Bioengineering, Rice University, Houston, Texas (United States); Lee, Hee Yoon [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Department of Electrical Engineering, Stanford University, Stanford, California (United States); Groves, Andrew K. [Department of Neuroscience, Department of Molecular and Human Genetics, and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas (United States); Zuo, Jian [Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, Tennessee (United States); Applegate, Brian E. [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States)

    2015-12-31

    Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering.

  13. Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Mehrnaz Karimi

    1992-04-01

    Full Text Available People with profound hearing loss are not able to use some kinds of conventional amplifiers due to the nature of their loss . In these people, hearing sense is stimulated only when the auditory nerve is activated via electrical stimulation. This stimulation is possible through cochlear implant. In fact, for the deaf people who have good mental health and can not use surgical and medical treatment and also can not benefit from air and bone conduction hearing aids, this device is used if they have normal central auditory system. The basic parts of the device included: Microphone, speech processor, transmitter, stimulator and receiver, and electrode array.

  14. Cochlear Implant

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this text, the authors recall the main principles and data ruling cochlear implants. Then, a first circle of technical equipment for assistance is presented. This circle includes: device setting (DS), Electrically evoked Auditory Brainstem Responses (EABR), Neural Response Telemetry (NRT), Stapedial Reflex (SR) and Electrodogram Acquisition (EA). This first cycle becomes more and more important as children are implanted younger and younger; the amount of data available with this assistance makes necessary the use of models (implicit or explicit) to handle this information. Consequently, this field is more open than ever.

  15. Inner ear hair cell regeneration A look from the past to the future

    Institute of Scientific and Technical Information of China (English)

    Francisco Santaolalla; Carlos Salvador; Agustn Martnez; Jose Mara Snchez; Ana Snchez del Rey

    2013-01-01

    Most recent studies on regeneration of inner ear hair cel s focus on use of stem cel s, gene therapy and neurotrophic factors. Cochlear gene therapy has been successful y used in the treatment of neu-rosensory hearing loss. This suggests that cochlear hair cel regeneration is possible. The objective of this paper is to review research and clinical application of inner near hair cel regeneration.

  16. Clonal Expansion of Lgr5-Positive Cells from Mammalian Cochlea and High-Purity Generation of Sensory Hair Cells

    Directory of Open Access Journals (Sweden)

    Will J. McLean

    2017-02-01

    Full Text Available Death of cochlear hair cells, which do not regenerate, is a cause of hearing loss in a high percentage of the population. Currently, no approach exists to obtain large numbers of cochlear hair cells. Here, using a small-molecule approach, we show significant expansion (>2,000-fold of cochlear supporting cells expressing and maintaining Lgr5, an epithelial stem cell marker, in response to stimulation of Wnt signaling by a GSK3β inhibitor and transcriptional activation by a histone deacetylase inhibitor. The Lgr5-expressing cells differentiate into hair cells in high yield. From a single mouse cochlea, we obtained over 11,500 hair cells, compared to less than 200 in the absence of induction. The newly generated hair cells have bundles and molecular machinery for transduction, synapse formation, and specialized hair cell activity. Targeting supporting cells capable of proliferation and cochlear hair cell replacement could lead to the discovery of hearing loss treatments.

  17. Functional expression of P2X4 receptor in capillary endothelial cells of the cochlear spiral ligament and its role in regulating the capillary diameter

    OpenAIRE

    Wu, T; M. Dai; Shi, X.R.; Jiang, Z. G.; Nuttall, A.L

    2011-01-01

    The cochlear lateral wall generates the endocochlear potential (EP), which creates a driving force for the hair cell transduction current and is essential for normal hearing. Blood flow at the cochlear lateral wall is critically important for maintaining the EP. The vulnerability of the EP to hypoxia suggests that the blood flow in the cochlear lateral wall is dynamically and precisely regulated to meet the changing metabolic needs of the cochlear lateral wall. It has been reported that ATP, ...

  18. Cochlear-Meningitis Vaccination

    Science.gov (United States)

    ... AcademyU Home Study Course Maintenance of Certification Conferences & Events ... you should know Children with cochlear implants are more likely to get bacterial meningitis than children without cochlear implants. In addition, ...

  19. Semicircular canals circumvent brownian motion overload of mechanoreceptor hair cells

    NARCIS (Netherlands)

    Muller, Mees; Heeck, Kier; Elemans, Coen P.H.

    2016-01-01

    Vertebrate semicircular canals (SCC) first appeared in the vertebrates (i.e. ancestral fish) over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as

    compared to cochlear hair cells are distinctly longer (70 vs. 7 μm), 10 times more compliant to bending (4

  20. 小鼠耳蜗内外毛细胞胞吞功能的实验研究%Different patterns of endocytosis identified in murine cochlear inner and outer hair cells

    Institute of Scientific and Technical Information of China (English)

    李四军; 柳柯; 唐嗣泉; 杨仕明

    2015-01-01

    目的:研究小鼠内外毛细胞胞吞功能的异同,探讨毛细胞胞吞功能与动物听功能之间的关系。方法选择出生后1月龄的正常C57BL/6J小鼠耳蜗基底膜在体外培养,以染料FM1-43为胞吞示踪剂,应用活细胞成像技术观察耳蜗内外毛细胞胞吞现象。结果内毛细胞的胞吞活动主要集中在细胞底部及核下区,而外毛细胞的胞吞活动则主要集中在核上区和外侧壁区。而且,在不同的观察时间点上,内毛细胞对FM1-43的摄入量均显著高于外毛细胞(P<0.05)。结论内毛细胞的胞吞活动集中出现在细胞底部及核下区,说明这种胞吞活动与内毛细胞带状突触的功能密切相关;外毛细胞的胞吞活动主要出现在核上区及细胞外侧壁,表明这种活动更多参与了外毛细胞纤毛及离子通道。内毛细胞比外毛细胞具有更强大的胞吞功能,表明内毛细胞在听功能的发育和维持中发挥着更为关键的作用。%Objective To report different patterns of endocytosis in murine cochlear inner and outer hair cells (IHCs&OHCs). Methods Normal C57BL/6J mice (1 month old) were used to observe different patterns of endocytosis in IHCs and OHCs in vitro using live cell imaging of FM1-43. Results Intense fluorescence den-sity of FM1-43 indicating massive endocytosis activities was identified at the base and blow the nucleus in IHCs. In contrast, major endocytosis activities in OHCs were found at or near the lateral cellular wall and above the nucleus. FM1-43 uptake in IHCs was higher than that in OHCs (P<0.05). Conclusion Active endocy-tosis at or near the basolateral area of the IHC suggests that endocytosis in IHCs may involve ribbon synapse plasticity. Endocytosis activities near the lateral wall and in the supranuclear area in OHC indicate that endocy-tosis in OHC involves tip-links or iron channels. Higher levels of FM1-43 uptake by IHCs may indicate IHC’s key roles in hearing

  1. Nonlinear cochlear mechanics.

    Science.gov (United States)

    Zweig, George

    2016-05-01

    An earlier paper characterizing the linear mechanical response of the organ of Corti [J. Acoust. Soc. Am. 138, 1102-1121 (2015)] is extended to the nonlinear domain. Assuming the existence of nonlinear oscillators nonlocally coupled through the pressure they help create, the oscillator equations are derived and examined when the stimuli are modulated tones and clicks. The nonlinearities are constrained by the requirements of oscillator stability and the invariance of zero crossings in the click response to changes in click amplitude. The nonlinear oscillator equations for tones are solved in terms of the fluid pressure that drives them, and its time derivative, presumably a proxy for forces created by outer hair cells. The pressure equation is reduced to quadrature, the integrand depending on the oscillators' responses. The resulting nonlocally coupled nonlinear equations for the pressure, and oscillator amplitudes and phases, are solved numerically in terms of the fluid pressure at the stapes. Methods for determining the nonlinear damping directly from measurements are described. Once the oscillators have been characterized from their tone and click responses, the mechanical response of the cochlea to natural sounds may be computed numerically. Signal processing inspired by cochlear mechanics opens up a new area of nonlocal nonlinear time-frequency analysis.

  2. Hair Removal

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Hair Removal KidsHealth > For Teens > Hair Removal A A A ... recommend an electrologist with the proper credentials. Laser Hair Removal How It Works: A laser is directed through ...

  3. Dry hair

    Science.gov (United States)

    ... normally style your hair? Do you use a hair dryer? What type? How often? What other symptoms are also present? Diagnostic tests that may be performed include: Examination of the hair under a microscope Blood tests

  4. Hair cosmetics.

    Science.gov (United States)

    Draelos, Z K

    1991-01-01

    Alterations in the cuticle, cortex, and medulla are necessary to modify the hair cosmetically. The hair can be modified externally by the use of shampoos to remove excess sebum, conditioners to restore shine, and styling aids to increase manageability. Several different formulations of all these products exist, depending on the needs of the patient. Furthermore, the hair can be modified both externally and internally through the use of hair dyes, permanent waving lotions, and hair straighteners. Use of these products causes external damage to the hair shaft by disrupting the overlapping cuticular scales, rendering the hair susceptible to static electricity and the effects of humidity while decreasing manageability and shine. Internal damage created by these products decreases the hair shaft's elastic properties, allowing increased hair breakage. The dermatologist can better aid the patient with hair difficulties if he or she has an understanding of the formulation and effects of products designed to cleanse, beautify, and modify the hair.

  5. Cochlear Implantation in Children with Cochlear Malformation.

    Science.gov (United States)

    Saikawa, Etsuko; Takano, Kenichi; Ogasawara, Noriko; Tsubomatsu, Chieko; Takahashi, Nozomi; Shirasaki, Hideaki; Himi, Tetsuo

    2016-01-01

    Cochlear implantation (CI) has proven to be an effective treatment for severe bilateral sensorineural hearing loss (SNHL). Inner ear malformation is a rare anomaly and occurs in approximately 20% of cases with congenital SNHL. In cases with cochlear malformation, CI can be successfully performed in nearly all patients, the exceptions being those with complete labyrinthine and cochlear aplasia. It is important to evaluate the severity of inner ear deformity and other associated anomalies during the preimplantation radiological assessment in order to identify any complication that may potentially occur during the surgery and subsequent patient management.

  6. Modulation of cochlear afferent response by the lateral olivocochlear system: activation via electrical stimulation of the inferior colliculus.

    Science.gov (United States)

    Groff, J Alan; Liberman, M Charles

    2003-11-01

    The olivocochlear (OC) efferent innervation of the mammalian inner ear consists of two subdivisions, medial (MOC) and lateral (LOC), with different peripheral terminations on outer hair cells and cochlear afferent terminals, respectively. The cochlear effects of electrically activating MOC efferents are well known, i.e., response suppression effected by reducing outer hair cells' contribution to cochlear amplification. LOC peripheral effects are unknown, because their unmyelinated axons are difficult to electrically stimulate. Here, stimulating electrodes are placed in the inferior colliculus (IC) to indirectly activate the LOC system, while recording cochlear responses bilaterally from anesthetized guinea pigs. Shocks at some IC sites produced novel cochlear effects attributable to activation of the LOC system: long-lasting (5-20 min) enhancement or suppression of cochlear neural responses (compound action potentials and round window noise), without changes in cochlear responses dominated by outer hair cells (otoacoustic emissions and cochlear microphonics). These novel effects also differed from classic MOC effects in their lack of dependence on the level and frequency of the acoustic stimulus. These effects disappeared on sectioning the entire OC bundle, but not after selective lesioning of the MOC tracts or the cochlea's autonomic innervation. We conclude that the LOC pathway comprises two functional subdivisions, capable of inducing slow increases or decreases in response magnitudes in the auditory nerve. Such a system may be useful in maintaining accurate binaural comparisons necessary for sound localization in the face of slow changes in interaural sensitivity.

  7. Predicting effects of impaired cochlear processing on consonant discrimination in stationary noise

    DEFF Research Database (Denmark)

    Jepsen, Morten Løve; Dau, Torsten; Ghitza, Oded

    Cochlear hearing loss is typically associated with reduced sensitivity due to inner hair-cell (IHC) and outer hair-cell (OHC) dysfunction. OHC dysfunction also leads to supra-threshold deficits, such as reduced basilar-membrane (BM) compression as well as reduced frequency selectivity and tempora...... resolution. Listeners with a cochlear damage typically have difficulties with speech understanding in the presence of background noise. In this study, the goal was to investigate the relation between individual consonant confusions in stationary noise and deficits in cochlear signal....... Thus, an incomplete representation of the speech sounds due to deficits in cochlear processing could be related to the performance in the speech perception task. In addition, it was studied to what extent the data could be accounted for based on reduced sensitivity only – assuming that BM compression......, such as the evaluation of hearing-instrument signal processing, where the effects of specific processing strategies can be simulated for individual hearing losses....

  8. Body Hair

    Science.gov (United States)

    ... To avoid spreading infections, don’t share razors. Hair removal creams, gels, and liquids (depilatories) These use chemicals ... electrologist with a current license or certification. Laser hair removal Light is beamed through the skin to stop ...

  9. Your Hair

    Science.gov (United States)

    ... or some other combination? Hair color comes from melanin (say: MEL-uh-nun), the substance that gives ... its pigment. The lighter someone's hair, the less melanin there is. A person with brown or black ...

  10. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  11. Hair Loss

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    ... enough protein from non-meat sources. And some athletes are at higher risk for hair loss because they may be more likely to develop iron-deficiency anemia. Disruption of the hair growth cycle. ...

  12. Hair Loss

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    ... loss at the scarred areas. These conditions include lichen planus, some types of lupus and sarcoidosis. Hair- ... increase your risk of hair loss, including: Family history Age Poor nutrition Certain medical conditions, such as ...

  13. Hair transplant

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007205.htm Hair transplant To use the sharing features on this page, please enable JavaScript. A hair transplant is a surgical procedure to improve baldness. Description ...

  14. MUSIC AND COCHLEAR IMPLANTS

    Institute of Scientific and Technical Information of China (English)

    Mao Yitao; Xu Li

    2013-01-01

    Currently, most people with modern multichannel cochlear implant systems can understand speech in qui-et environment very well. However, studies in recent decades reported a lack of satisfaction in music percep-tion with cochlear implants. This article reviews the literature on music ability of cochlear implant users by presenting a systematic outline of the capabilities and limitations of cochlear implant recipients with regard to their music perception as well as production. The review also evaluates the similarities and differences be-tween electric hearing and acoustic hearing regarding music perception. We summarize the research results in terms of the individual components of music (e.g., rhythm, pitch, and timbre). Finally, we briefly intro-duce the vocal singing of prelingually-deafened children with cochlear implants as evaluated by acoustic measures.

  15. Hair cosmetics

    Directory of Open Access Journals (Sweden)

    Nina Madnani

    2013-01-01

    Full Text Available The hair cosmetic industry has undergone a revolutionary change over the last two decades. The focus has dramatically veered from merely cleaning to repair, increasing the tensile strength, reducing oxidative damage, and stimulating growth. Newer shorter procedures to make hair look naturally more lustrous, smooth, and manageable have evolved. Specialized grooming products have been formulated to cleanse, calm, and condition the hair, and are tailored for different hair-types, for example, dry, dry-damaged, oily, colored, and gray hair. Other products are formulated to alter the color or structure of the hair shaft, for example, hair dyes, perming/relaxing. Hair sprays and waxes/gels, can alter the ′lift′ of the hair-shaft. Although dermatologists are experts in managing scalp and hair diseases, the esthetic applications of newer cosmetic therapies still remain elusive. This article attempts to fill the lacunae in our knowledge of hair cosmetics and esthetic procedures relevant in today′s rapidly changing beauty-enhancing industry, with special emphasis on the Indian scenario for chemical and ′natural′ hair products.

  16. Hair cosmetics.

    Science.gov (United States)

    Madnani, Nina; Khan, Kaleem

    2013-01-01

    The hair cosmetic industry has undergone a revolutionary change over the last two decades. The focus has dramatically veered from merely cleaning to repair, increasing the tensile strength, reducing oxidative damage, and stimulating growth. Newer shorter procedures to make hair look naturally more lustrous, smooth, and manageable have evolved. Specialized grooming products have been formulated to cleanse, calm, and condition the hair, and are tailored for different hair-types, for example, dry, dry-damaged, oily, colored, and gray hair. Other products are formulated to alter the color or structure of the hair shaft, for example, hair dyes, perming/relaxing. Hair sprays and waxes/gels, can alter the 'lift' of the hair-shaft. Although dermatologists are experts in managing scalp and hair diseases, the esthetic applications of newer cosmetic therapies still remain elusive. This article attempts to fill the lacunae in our knowledge of hair cosmetics and esthetic procedures relevant in today's rapidly changing beauty-enhancing industry, with special emphasis on the Indian scenario for chemical and 'natural' hair products.

  17. Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration.

    Science.gov (United States)

    Lee, Sang Goo; Huang, Mingqian; Obholzer, Nikolaus D; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A; Megason, Sean G; Li, Huawei; Chen, Zheng-Yi

    2016-01-01

    Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration.

  18. Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration.

    Directory of Open Access Journals (Sweden)

    Sang Goo Lee

    Full Text Available Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration.

  19. Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration

    Science.gov (United States)

    Obholzer, Nikolaus D.; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A.; Megason, Sean G.; Li, Huawei; Chen, Zheng-Yi

    2016-01-01

    Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration. PMID:27351484

  20. Cochlear implantation in children with keratitis-ichthyosis-deafness (KID) syndrome: outcomes in three cases.

    Science.gov (United States)

    Barker, Elizabeth J; Briggs, Robert Js

    2009-09-01

    Three children with keratitis-ichthyosis-deafness (KID) syndrome received cochlear implants at the Royal Victorian Eye and Ear Hospital. KID syndrome is a rare genodermatosis associated with mutation of the connexin-26 gene with characteristics affecting skin, hair, vision and hearing. Ichthyotic involvement of the ear canal epithelium and associated non-erosive keratosis obturans complicate hearing assessment and aid fitting. The tendency to eczematous dermatitis and otitis media is an additional problem with cochlear implantation. All cases have required additional medical management, however the outcomes show that the cochlear implant can be effective in these patients.

  1. Benefits and Risks of Cochlear Implants

    Science.gov (United States)

    ... Prosthetics Cochlear Implants Benefits and Risks of Cochlear Implants Share Tweet Linkedin Pin it More sharing options ... Cochlear Implants What are the Benefits of Cochlear Implants? For people with implants: Hearing ranges from near ...

  2. The role of G protein-coupled receptors in cochlear planar cell polarity.

    Science.gov (United States)

    Sun, Jinpeng; Zhang, Daolai; Wang, Yanfei; Lin, Hal; Yu, Xiao; Xu, Zhigang

    2016-08-01

    Planar cell polarity (PCP) is defined as the coordinated alignment of cell polarity across the tissue plane, which is important for the integration of cells into tissues. One of the best examples of PCP is in the cochlear epithelium. Several core PCP proteins have been identified to play important roles in PCP regulation, in which these proteins form complexes and associate with the cell membrane asymmetrically, mediating intercellular PCP signal transduction. Among the core PCP proteins are two G protein-coupled receptors (GPCRs), Celsr and Frizzled, both of which have been shown to play important roles in cochlear PCP regulation. Celsr and Frizzled genes are expressed in the cochlear sensory epithelium, and Frizzled1, 2, 3 and 6 show asymmetric localizations on the cell membrane of hair cells or supporting cells. In the animal model, Celsr1, Frizzled2 and Frizzled3/6 mutant or knockout mice have profound cochlear PCP deficits. Downstream of GPCR signaling, Gαi was shown to asymmetrically localize on the apical surface of hair cells, together with LGN and mInsc, Gαi controls cochlear PCP in a cell-autonomous way. Inactivity of Gαi, LGN or mInsc results in PCP deficits in the mouse cochlea. We hypothesize that GPCR-Gαi coupling plays a pivotal role in cochlear PCP regulation via connecting the intercellular PCP signals with cell-autonomous PCP machinery. Further investigations are needed to fully understand the mechanism of cochlear PCP regulation.

  3. C57 BL/6J小鼠听力及耳蜗毛细胞活性的年龄相关性研究%Study of the Correction between the Age Related Hearing Loss and the Cytoactivity Factors of the Cochlear Hair Cell in C57BL/6J Mice

    Institute of Scientific and Technical Information of China (English)

    周良强; 吴绍苓; 王燕; 褚汉启; 崔永华

    2009-01-01

    Objective To establish the mice model of AHL, to investigate the relationship between AHL and the cytoactive factors of the cochlear hair cells in C57BL/6J mice, and to classify the presbycusis models of the C57BL/6J mice. Methods C57BL/6J mice were divided into 6 experimental groups by age (A: 3 months old(m), B: 8 m, C: 9 m, D: 10 m, F: 17 m, G: 18 m) . The auditory functions mice were measured by auditory brainstem response (ABR) with the stimulus click and toneburst at 6 kHz and 8 kHz. 3 months later, Groups C , G, E and H were tested again for ABR. After ABR testing, the cytoactive of the hair cells was detected by succinate dehydrogenase staining and surface preparation technique(two mice from each group except groups C and G). Results The ABR thresholds elevated with age, and the marked change of the cochlea was the degeneration of the cytoactive of the cochlear hair cells, especially those of the outer hair cells. In the beginning, the basement of the basal membrane suffered from the mitochondrion degeneration in the outer hair cells, then it spread to the top region. Subsequently, the inner hair cells were involved. Conclusion C57BL/6J mouse was a typical animal model for the AHL,and the main change of the cochlea was the degeneration of the hair cells, especially the outer hair cells. Thus, C57BL/6J mice can be used as a suitable animal model for the study of presbycusis.%目的 建立年龄相关性听力损失(age-related hearing loss,AHL)的小鼠动物模型,探讨C57BL/6J小鼠发生AHL与毛细胞活性变化的关系,并初步对C57BL/6J小鼠AHL模型进行AHL的病理分类.方法 按3、8、9、10、17、18月龄段分6组培育C57BL/6J小鼠,各组分别进行听性脑干反应(ABR)测试,对耳蜗毛细胞行琥珀酸脱氢酶染色并作基底膜硬铺片,观察各年龄段小鼠内外毛细胞线粒体琥珀酸脱氢酶的活性.结果 C57BL/6J小鼠随年龄增大,ABR阈值明显增高,在3月龄到9月龄期间ABR平均反应阈值增大

  4. Hearing Preservation in Cochlear Implant Surgery

    Directory of Open Access Journals (Sweden)

    Priscila Carvalho Miranda

    2014-01-01

    Full Text Available In the past, it was thought that hearing loss patients with residual low-frequency hearing would not be good candidates for cochlear implantation since insertion was expected to induce inner ear trauma. Recent advances in electrode design and surgical techniques have made the preservation of residual low-frequency hearing achievable and desirable. The importance of preserving residual low-frequency hearing cannot be underestimated in light of the added benefit of hearing in noisy atmospheres and in music quality. The concept of electrical and acoustic stimulation involves electrically stimulating the nonfunctional, high-frequency region of the cochlea with a cochlear implant and applying a hearing aid in the low-frequency range. The principle of preserving low-frequency hearing by a “soft surgery” cochlear implantation could also be useful to the population of children who might profit from regenerative hair cell therapy in the future. Main aspects of low-frequency hearing preservation surgery are discussed in this review: its brief history, electrode design, principles and advantages of electric-acoustic stimulation, surgical technique, and further implications of this new treatment possibility for hearing impaired patients.

  5. Semicircular Canals Circumvent Brownian Motion Overload of Mechanoreceptor Hair Cells

    Science.gov (United States)

    Muller, Mees; Heeck, Kier

    2016-01-01

    Vertebrate semicircular canals (SCC) first appeared in the vertebrates (i.e. ancestral fish) over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as compared to cochlear hair cells are distinctly longer (70 vs. 7 μm), 10 times more compliant to bending (44 vs. 500 nN/m), and have a 100-fold higher tip displacement threshold (mechanoreceptors of the SCC. PMID:27448330

  6. Cochlear Implant in Adults

    Directory of Open Access Journals (Sweden)

    Jaleh Samadi

    2003-09-01

    Full Text Available Cochlear implant is the result of a great combination and collaboration of engineering and medicine. It is mainly because it has the most conflict with the human nervous system among all prosthesis. Cochlear implant helps a child with profound hearing loss to understand and articulate speech and let an adult person with hearing loss communicate with people by phone. Although these wonderful results could not be seen in all patients, will let us know about the great scientific findings.

  7. A Mixed Mode Cochlear Amplifier Including Neural Feedback

    Science.gov (United States)

    Flax, Matthew R.; Holmes, W. Harvey

    2011-11-01

    The mixed mode cochlear amplifier (MMCA) model is derived from the physiology of the cochlea. It is comprised of three main elements of the peripheral hearing system: the cochlear mechanics, hair cell motility, and neurophysiology. This model expresses both active compression wave and active traveling wave modes of operation. The inclusion of a neural loop with a time delay, and a new paradigm for the mechanical response of the outer hair cells, are believed to be unique features of the MMCA. These elements combine to form an active feedback loop to constitute the cochlear amplifier, whose input is a passive traveling wave vibration. The result is a cycle-by-cycle amplifier with nonlinear response. This system can assume an infinite number of different operating states. The stable state and the first few amplitude-limited unstable (Hopf-bifurcated) states are significant in describing the operation of the peripheral hearing system. A hierarchy of models can be constructed from this concept, depending on the amount of detail included. The simplest model of the MMCA is a nonlinear delay line resonator. It was found that even this simple MMCA version can explain a large number of hearing phenomena, at least qualitatively. This paper concentrates on explaining the fractional octave shift from the living to postmortem response in terms of the new model. Other mechanical, hair cell and neurological phenomena can also be accounted for by the MMCA, including two-tone suppression behavior, distortion product responses, otoacoustic emissions and neural spontaneous rates.

  8. Protective role of hydrogen sulfide against noise-induced cochlear damage: a chronic intracochlear infusion model.

    Directory of Open Access Journals (Sweden)

    Xu Li

    Full Text Available BACKGROUND: A reduction in cochlear blood flow plays an essential role in noise-induced hearing loss (NIHL. The timely regulation of cochlear perfusion determines the progression and prognosis of NIHL. Hydrogen sulfide (H(2S has attracted increasing interest as a vasodilator in cardiovascular systems. This study identified the role of H(2S in cochlear blood flow regulation and noise protection. METHODOLOGY/PRINCIPAL FINDINGS: The gene and protein expression of the H(2S synthetase cystathionine-γ-lyase (CSE in the rat cochlea was examined using immunofluorescence and real-time PCR. Cochlear CSE mRNA levels varied according to the duration of noise exposure. A chronic intracochlear infusion model was built and artificial perilymph (AP, NaHS or DL-propargylglycine (PPG were locally administered. Local sodium hydrosulfide (NaHS significantly increased cochlear perfusion post-noise exposure. Cochlear morphological damage and hearing loss were alleviated in the NaHS group as measured by conventional auditory brainstem response (ABR, cochlear scanning electron microscope (SEM and outer hair cell (OHC count. The highest percentage of OHC loss occurred in the PPG group. CONCLUSIONS/SIGNIFICANCE: Our results suggest that H(2S plays an important role in the regulation of cochlear blood flow and the protection against noise. Further studies may identify a new preventive and therapeutic perspective on NIHL and other blood supply-related inner ear diseases.

  9. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Jerry D. Monroe

    2015-04-01

    Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

  10. Cochlear injury and adaptive plasticity of the auditory cortex

    Directory of Open Access Journals (Sweden)

    ANNA R. eFETONI

    2015-02-01

    Full Text Available Growing evidence suggests that cochlear stressors as noise exposure and aging can induce homeostatic/maladaptive changes in the central auditory system from the brainstem to the cortex. Studies centered on such changes have revealed several mechanisms that operate in the context of sensory disruption after insult (noise trauma, drug- or age-related injury. The oxidative stress is central to current theories of induced sensory neural hearing loss and aging, and interventions to attenuate the hearing loss are based on antioxidant agent. The present review addresses the recent literature on the alterations in hair cells and spiral ganglion neurons due to noise-induced oxidative stress in the cochlea, as well on the impact of cochlear damage on the auditory cortex neurons. The emerging image emphasizes that noise-induced deafferentation and upward spread of cochlear damage is associated with the altered dendritic architecture of auditory pyramidal neurons. The cortical modifications may be reversed by treatment with antioxidants counteracting the cochlear redox imbalance. These findings open new therapeutic approaches to treat the functional consequences of the cortical reorganization following cochlear damage.

  11. Auditory hair cell centrioles undergo confined Brownian motion throughout the developmental migration of the kinocilium.

    OpenAIRE

    Lepelletier, Léa; de Monvel, Jacques Boutet; Buisson, Johanna; Desdouets, Chantal; Petit, Christine

    2013-01-01

    Planar polarization of the forming hair bundle, the mechanosensory antenna of auditory hair cells, depends on the poorly characterized center-to-edge displacement of a primary cilium, the kinocilium, at their apical surface. Taking advantage of the gradient of hair cell differentiation along the cochlea, we reconstituted a map of the kinocilia displacements in the mouse embryonic cochlea. We then developed a cochlear organotypic culture and video-microscopy approach to monitor the movements o...

  12. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair...

  13. Cochlear implantation in congenital cochlear abnormalities.

    Science.gov (United States)

    Ahmad, R L; Lokman, S

    2005-08-01

    Many children have benefited from cochlear implant device including those with congenital malformation of the inner ear. The results reported in children with malformed cochlea are very encouraging. We describe 2 cases of Mondini's malformation with severe sensorineural hearing loss. Cochlear implantation was performed and both of them underwent post-implantation speech rehabilitation. Post-implantation, both of them were noted to respond to external sound. But the second case developed facial twitching a few months after the device was switched on. It is important to evaluate the severity of the inner ear deformity and the other associated anomalies in pre-implantation radiological assessment in order to identify the problem that may complicate the surgery and subsequent patient management.

  14. HAIR CELL-LIKE CELL GENERATION INDUCED BY NATURE CULTURE OF ADULT RAT AUDITORY EPITHELIUM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Hair cells are the mechanosensory cells thatconvert sound and motion signals into electrical i m-pulses in cochlear and vestibular end organs of innerear.Although mature mammals nor mally do notgenerate new hair cells,recentin vivoandin vitrostudies have demonstrated mitotic activity and i m-mature-looking hair cells in mammalian vestibularepithelia after exposure to ototoxic drugs[1-3],sug-gesting that vestibular hair cell regeneration inmammals may be inducible.However,the possibil-ity of auditory hair ce...

  15. Von Bekesy and cochlear mechanics

    NARCIS (Netherlands)

    Olson, Elizabeth S.; Duifhuis, Hendrikus; Steele, Charles R.

    2012-01-01

    Georg Bekesy laid the foundation for cochlear mechanics, foremost by demonstrating the traveling wave that is the substrate for mammalian cochlear mechanical processing. He made mechanical measurements and physical models in order to understand that fundamental cochlear response. In this tribute to

  16. Cochlear neuropathy in human presbycusis: Confocal analysis of hidden hearing loss in post-mortem tissue.

    Science.gov (United States)

    Viana, Lucas M; O'Malley, Jennifer T; Burgess, Barbara J; Jones, Dianne D; Oliveira, Carlos A C P; Santos, Felipe; Merchant, Saumil N; Liberman, Leslie D; Liberman, M Charles

    2015-09-01

    Recent animal work has suggested that cochlear synapses are more vulnerable than hair cells in both noise-induced and age-related hearing loss. This synaptopathy is invisible in conventional histopathological analysis, because cochlear nerve cell bodies in the spiral ganglion survive for years, and synaptic analysis requires special immunostaining or serial-section electron microscopy. Here, we show that the same quadruple-immunostaining protocols that allow synaptic counts, hair cell counts, neuronal counts and differentiation of afferent and efferent fibers in mouse can be applied to human temporal bones, when harvested within 9 h post-mortem and prepared as dissected whole mounts of the sensory epithelium and osseous spiral lamina. Quantitative analysis of five "normal" ears, aged 54-89 yrs, without any history of otologic disease, suggests that cochlear synaptopathy and the degeneration of cochlear nerve peripheral axons, despite a near-normal hair cell population, may be an important component of human presbycusis. Although primary cochlear nerve degeneration is not expected to affect audiometric thresholds, it may be key to problems with hearing in noise that are characteristic of declining hearing abilities in the aging ear.

  17. Amplitude recruitment of cochlear potential

    Institute of Scientific and Technical Information of China (English)

    LI Xingqi; SUN Wei; SUN Jianhe; YU Ning; JIANG Sichang

    2001-01-01

    Intracellular recordings were made from outer hair cells (OHC) and the cochlear microphonics (CM) were recorded from scala media (SM) in three turn of guinea pig cochlea,the compound action potential (CAP) were recorded at the round window (RW) before and after the animal were exposed to white noise. The results suggest that the nonlinear properties with “saduration” of Input/output (I/O) function of OHC AC recepter potential and CM were founded; the nonlinear properties with “Low”, “Platean” and “high” of CAP also were investigated. After explosion, the threshold shift of CAP has about 10 dB. The I/O of OHC responses and CM were changed in a linearizing (i.e., nonlinearity loss), the “platean” of I/O CAP disappeared and the growth rate of CAP amplitude were larger than before explosion. The response amplitude recruitment of OHC appears to result from reduction in gain (i.e., hearing loss); It was due to the nonlinear growth function of OHC receptor potentials was changed in linearzing that the basilar membrance motion was changed in linearizing. Since intensity coding in the inner ear depends on an interactions of nonlinear basilar membrance and nerve fibers. So that it must lead to a linearizing of CAP as input responses.

  18. The ultrastructure of cochlear afferent synapse of inner hair cells in C57BL/6J mice%C57BL/6J小鼠耳蜗内毛细胞传入神经突触的超微结构观察

    Institute of Scientific and Technical Information of China (English)

    施磊; 柳柯; 赵宁; 魏宏权; 刘红娟; 姜学钧

    2011-01-01

    目的 利用投射电镜观察C57Bl/6J小鼠耳蜗内毛细胞传人神经突触的形态和结构.方法 选择发育成熟的C57Bl/6J小鼠,ABR检测听力正常后获取耳蜗标本,分别经过半薄定位和超薄连续切片观察的方法寻找观察耳蜗内毛细胞传入神经突触的形态和结构,探讨发育成熟状态下小鼠耳蜗内毛细胞突触的形态和结构特点,并进一步分析它们可能出现的区域以及与周围解剖结构的关系.结果 在听力正常的C57Bl/6J小鼠的不同耳蜗内毛细胞核下区域可以观察到带状突触结构,包括ribbon、突触囊泡、突触间隙和突触后致密带等典型结构;然而有时即使是在听力正常的小鼠耳蜗内,也不能同时观察到这些结构的伞部,即内毛细胞带状突触的超微结构和形态可能表现出彼此之间存在明显区别的形式.结论 在听力正常的生理状态下,成熟小鼠(e57BL/6J)耳蜗内毛细胞突触的形态和结构处于动态变化之中,突触的个体形态和结构可以表现出不同的特点,而这种结构上的动态变化可能和突触功能的变化有关.%Objective To study the ultrastmctue of afferent synapse of inner hair cells ( IHCs ) in C57BL/6J mice. Method The adult c57BL/6J mice with normal hearing function were selected, and the cochleas were taken out and the semi and ultra sections were performed for the ultrastructural observation by transmission electron microscope(TEM). The ultrastructural properties within afferent synapses as well as structures nearby were analysized, and the potential correlation between the afferent synapses and other structures around was explored. Result The typical afferent synapse structure was observed including the presynaptic ribbon, synapse vesicles, the clear synapse cleft and the postsynaptic density(PSD) in mice with normal hearing ability. However, sometimes, those synaptic components could not be captured by TEM observation even in same cochlear section

  19. [Bilateral cochlear implantation].

    Science.gov (United States)

    Kronenberg, Jona; Migirov, Lela; Taitelbaum-Swead, Rikey; Hildesheimer, Minka

    2010-06-01

    Cochlear implant surgery became the standard of care in hearing rehabilitation of patients with severe to profound sensorineural hearing loss. This procedure may alter the lives of children and adults enabling them to integrate with the hearing population. In the past, implantation was performed only in one ear, despite the fact that binaural hearing is superior to unilateral, especially in noisy conditions. Cochlear implantation may be performed sequentially or simultaneously. The "sensitive period" of time between hearing loss and implantation and between the two implantations, when performed sequentially, significantly influences the results. Shorter time spans between implantations improve the hearing results after implantation. Hearing success after implantation is highly dependent on the rehabilitation process which includes mapping, implant adjustments and hearing training. Bilateral cochlear implantation in children is recommended as the proposed procedure in spite of the additional financial burden.

  20. The Effects of Urethane on Rat Outer Hair Cells

    Directory of Open Access Journals (Sweden)

    Mingyu Fu

    2016-01-01

    Full Text Available The cochlea converts sound vibration into electrical impulses and amplifies the low-level sound signal. Urethane, a widely used anesthetic in animal research, has been shown to reduce the neural responses to auditory stimuli. However, the effects of urethane on cochlea, especially on the function of outer hair cells, remain largely unknown. In the present study, we compared the cochlear microphonic responses between awake and urethane-anesthetized rats. The results revealed that the amplitude of the cochlear microphonic was decreased by urethane, resulting in an increase in the threshold at all of the sound frequencies examined. To deduce the possible mechanism underlying the urethane-induced decrease in cochlear sensitivity, we examined the electrical response properties of isolated outer hair cells using whole-cell patch-clamp recording. We found that urethane hyperpolarizes the outer hair cell membrane potential in a dose-dependent manner and elicits larger outward current. This urethane-induced outward current was blocked by strychnine, an antagonist of the α9 subunit of the nicotinic acetylcholine receptor. Meanwhile, the function of the outer hair cell motor protein, prestin, was not affected. These results suggest that urethane anesthesia is expected to decrease the responses of outer hair cells, whereas the frequency selectivity of cochlea remains unchanged.

  1. The Effects of Urethane on Rat Outer Hair Cells

    Science.gov (United States)

    Fu, Mingyu; Chen, Mengzi; Yang, Xueying

    2016-01-01

    The cochlea converts sound vibration into electrical impulses and amplifies the low-level sound signal. Urethane, a widely used anesthetic in animal research, has been shown to reduce the neural responses to auditory stimuli. However, the effects of urethane on cochlea, especially on the function of outer hair cells, remain largely unknown. In the present study, we compared the cochlear microphonic responses between awake and urethane-anesthetized rats. The results revealed that the amplitude of the cochlear microphonic was decreased by urethane, resulting in an increase in the threshold at all of the sound frequencies examined. To deduce the possible mechanism underlying the urethane-induced decrease in cochlear sensitivity, we examined the electrical response properties of isolated outer hair cells using whole-cell patch-clamp recording. We found that urethane hyperpolarizes the outer hair cell membrane potential in a dose-dependent manner and elicits larger outward current. This urethane-induced outward current was blocked by strychnine, an antagonist of the α9 subunit of the nicotinic acetylcholine receptor. Meanwhile, the function of the outer hair cell motor protein, prestin, was not affected. These results suggest that urethane anesthesia is expected to decrease the responses of outer hair cells, whereas the frequency selectivity of cochlea remains unchanged. PMID:28050287

  2. Hair loss

    Science.gov (United States)

    ... SA, Stough DB, Rogers NE. Hair restoration. In: Bolognia JL, Jorizzo JL, Schaffer JV, eds. Dermatology . 3rd ... Sinclair RD, El Shabrawi-Caelen L. Alopecias. In: Bolognia JL, Jorizzo JL, Schaffer JV, eds. Dermatology . 3rd ...

  3. Hair shape of curly hair.

    Science.gov (United States)

    Bernard, Bruno A

    2003-06-01

    The hair follicle is a unique composite organ, composed of epithelial and dermal compartments interacting with each other in a surprisingly autonomous way. This is a self-renewing organ that seems to be a true paradigm of epithelial and mesenchymal interactions. Each of the follicular compartments is endowed with a specific differentiation pathway under the control of an intricate network of growth factors, cytokines, and hormones. As observed for ethnic hairs, even the shape of the hair shaft is intrinsically programmed from the bulb.

  4. Auditory cortex basal activity modulates cochlear responses in chinchillas.

    Directory of Open Access Journals (Sweden)

    Alex León

    Full Text Available BACKGROUND: The auditory efferent system has unique neuroanatomical pathways that connect the cerebral cortex with sensory receptor cells. Pyramidal neurons located in layers V and VI of the primary auditory cortex constitute descending projections to the thalamus, inferior colliculus, and even directly to the superior olivary complex and to the cochlear nucleus. Efferent pathways are connected to the cochlear receptor by the olivocochlear system, which innervates outer hair cells and auditory nerve fibers. The functional role of the cortico-olivocochlear efferent system remains debated. We hypothesized that auditory cortex basal activity modulates cochlear and auditory-nerve afferent responses through the efferent system. METHODOLOGY/PRINCIPAL FINDINGS: Cochlear microphonics (CM, auditory-nerve compound action potentials (CAP and auditory cortex evoked potentials (ACEP were recorded in twenty anesthetized chinchillas, before, during and after auditory cortex deactivation by two methods: lidocaine microinjections or cortical cooling with cryoloops. Auditory cortex deactivation induced a transient reduction in ACEP amplitudes in fifteen animals (deactivation experiments and a permanent reduction in five chinchillas (lesion experiments. We found significant changes in the amplitude of CM in both types of experiments, being the most common effect a CM decrease found in fifteen animals. Concomitantly to CM amplitude changes, we found CAP increases in seven chinchillas and CAP reductions in thirteen animals. Although ACEP amplitudes were completely recovered after ninety minutes in deactivation experiments, only partial recovery was observed in the magnitudes of cochlear responses. CONCLUSIONS/SIGNIFICANCE: These results show that blocking ongoing auditory cortex activity modulates CM and CAP responses, demonstrating that cortico-olivocochlear circuits regulate auditory nerve and cochlear responses through a basal efferent tone. The diversity of the

  5. 快蛋白--耳蜗外毛细胞的一种新型马达蛋白%A New Type of Motor Protein-Prestin in the Cochlear out Hair Cells

    Institute of Scientific and Technical Information of China (English)

    李雪松; 熊鹰

    2004-01-01

    哺乳动物耳蜗外毛细胞(out hair cell, OHC)在机械刺激引起的膜电位改变的条件下,其胞体本身能发生与声音刺激相同步的伸长与收缩反应,即膜电位去极化时收缩,超极化时伸长,称为电能动性[1].它能反馈能量到振动的基底膜,对声音刺激起更精细的放大作用.这一发现使耳蜗对声音放大有了主动性的一面.目前发现一种新型的马达蛋白--快蛋白(prestin)是外毛细胞电能动性的分子基础[2].从而为在分子水平揭示耳蜗的主动功能提供了依据.

  6. [Hair shaft abnormalities].

    Science.gov (United States)

    Itin, P H; Düggelin, M

    2002-05-01

    Hair shaft disorders may lead to brittleness and uncombable hair. In general the hair feels dry and lusterless. Hair shaft abnormalities may occur as localized or generalized disorders. Genetic predisposition or exogenous factors are able to produce and maintain hair shaft abnormalities. In addition to an extensive history and physical examination the most important diagnostic examination to analyze a hair shaft problem is light microscopy. Therapy of hair shaft disorders should focus to the cause. In addition, minimizing traumatic influences to hair shafts, such as dry hair with an electric dryer, permanent waves and dyes is important. A short hair style is more suitable for such patients with hair shaft disorders.

  7. [Hair shaft anomalies].

    Science.gov (United States)

    Itin, P H

    1997-06-01

    Hair shaft disorders lead to brittle and uncombable hair. As a rule the hair feels dry and lusterless. Hair shaft abnormalities may present as localized of generalized alterations. Genetic predisposition and exogenous factors are able to produce hair shaft abnormalities. The most important examination to analyze a hair shaft problem is light microscopy. Treatment of hair shaft disorders should focus on the cause. In addition, minimizing traumatic influences to hair shafts, such as electric dryer, permanent waves and dyes is important.

  8. Hair follicle growth controls.

    Science.gov (United States)

    Stenn, K S; Combates, N J; Eilertsen, K J; Gordon, J S; Pardinas, J R; Parimoo, S; Prouty, S M

    1996-10-01

    Research in hair biology has embarked in the pursuit for molecules that control hair growth. Many molecules already have been associated with the controls of hair patterning, hair maturation, and hair cycling and differentiation. Knowing how these molecules work gives us the tools for understanding and treating patients with hair disorders.

  9. Patency of the cochlear aqueduct

    Energy Technology Data Exchange (ETDEWEB)

    Muren, C.; Vignaud, J.; Wilbrand, H.; Wilbrand, S.

    The patency of the cochlear aqueduct is discussed against the background of radioanatomic studies of 225 plastic casts of temporal bone specimens and additional experimental and clinical observations. The occasional presence of a wide venous channel running parallel with the cochlear aqueduct, as well as the existence of up to three accompanying venous channels can simulate a pathologically wide cochlear aqueduct radiographically. This could constitute a diagnostic pitfall in the absence of other clinical and radiographic signs of malformation.

  10. Cochlear implants in genetic deafness

    Institute of Scientific and Technical Information of China (English)

    Xuezhong Liu

    2014-01-01

    Genetic defects are one of the most important etiologies of severe to profound sensorineural hearing loss and play an important role in determining cochlear implantation outcomes. While the pathogenic mutation types of a number of deafness genes have been cloned, the pathogenesis mechanisms and their relationship to the outcomes of cochlear implantation remain a hot research area. The auditory performance is considered to be affected by the etiology of hearing loss and the number of surviving spiral ganglion cells, as well as others. Current research advances in cochlear implantation for hereditary deafness, especially the relationship among clinic-types, genotypes and outcomes of cochlear implantation, will be discussed in this review.

  11. Hearing preservation in cochlear implantation and drug treatment.

    Science.gov (United States)

    Barriat, Sebastien; Poirrier, Annelise; Malgrange, Brigitte; Lefebvre, Philippe

    2010-01-01

    Insertion of an electrode array into the cochlea produces immediate damage to the inner ear, which is responsible for a hearing loss. In addition, a delayed hearing loss can be observed. In order to maximize hearing preservation after insertion of an electrode and to enhance the performance of the cochlear implant, it has been proposed to deliver pharmacological agents to the inner ear. Molecules can be administered locally to the inner ear through a direct perilymphatic perfusion or through the round window membrane. These modalities of treatment have already been successfully applied to some patients with inner ear diseases. In this paper, we will review some basic aspects of drug delivery to the inner ear to prevent the degeneration of the neurosensory hair cells and auditory neurons, and the actual applicability to humans in order to maintain hearing function after the insertion of electrodes of a cochlear implant.

  12. Intracochlear Bleeding Enhances Cochlear Fibrosis and Ossification: An Animal Study.

    Directory of Open Access Journals (Sweden)

    Kyeung A Ryu

    Full Text Available The aim of this study was to investigate the effects of intracochlear bleeding during cochleostomy on cochlear inflammatory response and residual hearing in a guinea pig animal model. Auditory brainstem response threshold shifts were greater in blood injected ears (p<0.05. Interleukin-1β, interleukin-10, tumor necrosis factor-α and nitric oxide synthase 2, cytokines that are related to early stage inflammation, were significantly increased in blood injected ears compared to normal and cochleostomy only ears at 1 day after surgery; with the increased IL-1β being sustained until 3 days after the surgery (p<0.05. Hair cells were more severely damaged in blood injected ears than in cochleostomy only ears. Histopathologic examination revealed more extensive fibrosis and ossification in blood injected ears than cochleostomy only ears. These results show that intracochlear bleeding enhanced cochlear inflammation resulting in increased fibrosis and ossification in an experimental animal model.

  13. Hair colouring, permanent styling and hair structure.

    Science.gov (United States)

    Harrison, S; Sinclair, R

    2003-07-01

    Hair is an important component of body image and has immense psychological importance for both men and women. Women, in particular, over the ages have modified their appearance through changing their hair colour or style. Hair can be straight, wavy or curly, blonde, black, brown or red. These natural variations are an important part of our identity that can be manipulated according to the dictates of fashion, culture or society. Different types of hair have varying affinity for the different colouring and waving methods. Damaged hair also has a different affinity for hair products than normal healthy hair. The hair shaft is remarkably strong and resistant to the extremes of nature. Hair cosmetics are widely available and manipulate the structural properties of hair. Whilst most procedures are safe, there is considerable potential for damage to the hair and hair problems of acute onset, including hair breakage, hair loss and loss of condition, are frequently blamed on the last product used on the hair. Hair problems are particularly prevalent among people who repeatedly alter the natural style of their hair.

  14. Efter cochlear implant

    DEFF Research Database (Denmark)

    Højen, Anders

    Dit barn har netop fået et cochlear implant. Hvad nu? Skal barnet fokusere udelukkende på at lære talt sprog, eller skal det også lære/fortsætte med tegnsprog eller støttetegn? Det er et vanskeligt spørgsmål, og før valget foretages, er det vigtigt at vurdere hvilke konsekvenser valget har, dels...... for den sproglige udvikling isoleret set, og dels for barnets udvikling ud fra en helhedsbetragtning. Dette indlæg fokuserer på, hvilke forventninger man kan have til cochlear implant-brugeres sproglige udvikling med talt sprog alene, hhv. med to sprog (tale og tegn). Disse forventninger er baseret på...

  15. Efter cochlear implant

    DEFF Research Database (Denmark)

    Højen, Anders

    2007-01-01

      Dit barn har netop fået et cochlear implant. Hvad nu? Skal barnet fokusere udelukkende på at lære talt sprog, eller skal det også lære/fortsætte med tegnsprog eller støttetegn? Det er et vanskeligt spørgsmål, og før valget foretages, er det vigtigt at vurdere hvilke konsekvenser valget har, dels...... for den sproglige udvikling isoleret set, og dels for barnets udvikling ud fra en helhedsbetragtning. Dette indlæg fokuserer på, hvilke forventninger man kan have til cochlear implant-brugeres sproglige udvikling med talt sprog alene, hhv. med to sprog (tale og tegn). Disse forventninger er baseret på...

  16. Ototoxicity of paclitaxel in rat cochlear organotypic cultures

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yang [Shanghai University of Traditional Chinese Medicine, Shanghai 201203 (China); Center for Hearing and Deafness, University at Buffalo, NY 14214 (United States); Ding, Dalian; Jiang, Haiyan [Center for Hearing and Deafness, University at Buffalo, NY 14214 (United States); Shi, Jian-rong [Shanghai University of Traditional Chinese Medicine, Shanghai 201203 (China); Salvi, Richard [Center for Hearing and Deafness, University at Buffalo, NY 14214 (United States); Roth, Jerome A., E-mail: jaroth@buffalo.edu [Department of Pharmacology and Toxicology, University at Buffalo, NY 14214 (United States)

    2014-11-01

    Paclitaxel (taxol) is a widely used antineoplastic drug employed alone or in combination to treat many forms of cancer. Paclitaxel blocks microtubule depolymerization thereby stabilizing microtubules and suppressing cell proliferation and other cellular processes. Previous reports indicate that paclitaxel can cause mild to moderate sensorineural hearing loss and some histopathologic changes in the mouse cochlea; however, damage to the neurons and the underlying cell death mechanisms are poorly understood. To evaluate the ototoxicity of paclitaxel in more detail, cochlear organotypic cultures from postnatal day 3 rats were treated with paclitaxel for 24 or 48 h with doses ranging from 1 to 30 μM. No obvious histopathologies were observed after 24 h treatment with any of the paclitaxel doses employed, but with 48 h treatment, paclitaxel damaged cochlear hair cells in a dose-dependent manner and also damaged auditory nerve fibers and spiral ganglion neurons (SGN) near the base of the cochlea. TUNEL labeling was negative in the organ of Corti, but positive in SGN with karyorrhexis 48 h after 30 μM paclitaxel treatment. In addition, caspase-6, caspase-8 and caspase-9 labeling was present in SGN treated with 30 μM paclitaxel for 48 h. These results suggest that caspase-dependent apoptotic pathways are involved in paclitaxel-induced damage of SGN, but not hair cells in cochlea. - Highlights: • Paclitaxel was toxic to cochlear hair cells and spiral ganglion neurons. • Paclitaxel-induced spiral ganglion degeneration was apoptotic. • Paclitaxel activated caspase-6, -8 and -8 in spiral ganglion neurons.

  17. Tumor Necrosis Factor-α-Induced Ototoxicity in Mouse Cochlear Organotypic Culture.

    Directory of Open Access Journals (Sweden)

    Qian Wu

    Full Text Available Tumor necrosis factor (TNF-α is a cytokine involved in acute inflammatory phase reactions, and is the primary upstream mediator in the cochlear inflammatory response. Treatment of the organ of Corti with TNF-α can induce hair cell damage. However, the resulting morphological changes have not been systematically examined. In the present study, cochlear organotypic cultures from neonatal mice were treated with various concentrations and durations of TNF-α to induce inflammatory responses. Confocal microscopy was used to evaluate the condition of hair cells and supporting cells following immunohistochemical staining. In addition, the ultrastructure of the stereocilia bundle, hair cells, and supporting cells were examined by scanning and transmission electron microscopy. TNF-α treatment resulted in a fusion and loss of stereocilia bundles in hair cells, swelling of mitochondria, and vacuolation and degranulation of the endoplasmic reticulum. Disruption of tight junctions between hair cells and supporting cells was also observed at high concentrations. Hair cell loss was preceded by apoptosis of Deiters' and pillar cells. Taken together, these findings detail the morphological changes in the organ of Corti after TNF-α treatment, and provide an in vitro model of inflammatory-induced ototoxicity.

  18. Continued expression of GATA3 is necessary for cochlear neurosensory development.

    Directory of Open Access Journals (Sweden)

    Jeremy S Duncan

    Full Text Available Hair cells of the developing mammalian inner ear are progressively defined through cell fate restriction. This process culminates in the expression of the bHLH transcription factor Atoh1, which is necessary for differentiation of hair cells, but not for their specification. Loss of several genes will disrupt ear morphogenesis or arrest of neurosensory epithelia development. We previously showed in null mutants that the loss of the transcription factor, Gata3, results specifically in the loss of all cochlear neurosensory development. Temporal expression of Gata3 is broad from the otic placode stage through the postnatal ear. It therefore remains unclear at which stage in development Gata3 exerts its effect. To better understand the stage specific effects of Gata3, we investigated the role of Gata3 in cochlear neurosensory specification and differentiation utilizing a LoxP targeted Gata3 line and two Cre lines. Foxg1(Cre∶Gata3(f/f mice show recombination of Gata3 around E8.5 but continue to develop a cochlear duct without differentiated hair cells and spiral ganglion neurons. qRT-PCR data show that Atoh1 was down-regulated but not absent in the duct whereas other hair cell specific genes such as Pou4f3 were completely absent. In addition, while Sox2 levels were lower in the Foxg1(Cre:Gata3(f/f cochlea, Eya1 levels remained normal. We conclude that Eya1 is unable to fully upregulate Atoh1 or Pou4f3, and drive differentiation of hair cells without Gata3. Pax2-Cre∶Gata3(f/f mice show a delayed recombination of Gata3 in the ear relative to Foxg1(Cre:Gata3(f/f . These mice exhibited a cochlear duct containing patches of partially differentiated hair cells and developed only few and incorrectly projecting spiral ganglion neurons. Our conditional deletion studies reveal a major role of Gata3 in the signaling of prosensory genes and in the differentiation of cochlear neurosenory cells. We suggest that Gata3 may act in combination with Eya1, Six1, and

  19. Hair care and dyeing.

    Science.gov (United States)

    Draelos, Zoe Diana

    2015-01-01

    Alopecia can be effectively camouflaged or worsened through the use of hair care techniques and dyeing. Proper hair care, involving hair styling and the use of mild shampoos and body-building conditioners, can amplify thinning scalp hair; however, chemical processing, including hair dyeing, permanent waving, and hair straightening, can encourage further hair loss through breakage. Many patients suffering from alopecia attempt to improve their hair through extensive manipulation, which only increases problems. Frequent haircuts to minimize split ends, accompanied by gentle handling of the fragile fibers, is best. This chapter offers the dermatologist insight into hair care recommendations for the alopecia patient.

  20. Sonic hedgehog (SHH) promotes the differentiation of mouse cochlear neural progenitors via the Math1-Brn3.1 signaling pathway in vitro.

    Science.gov (United States)

    Hu, Xiaohua; Huang, Jianmin; Feng, Ling; Fukudome, Shinji; Hamajima, Yuki; Lin, Jizhen

    2010-04-01

    Sonic hedgehog (SHH) is essential for the development of the cochlear duct that harbors the organ of Corti. However, little is known about the molecular signaling pathway through which SHH promotes the development of the organ of Corti, especially cochlear sensory epithelial cells. In this study, we demonstrated that SHH contributes to the differentiation of cochlear neural progenitors (CNPs), which are derived from the postnatal day 1 organ of Corti in mice. Addition of SHH to CNPs increased the formation of epithelial cell islands, simultaneously activated the expression of Math1 that is a transcription factor for the initial differentiation of auditory hair cells. The increased expression of Math1 then regulated the promoter activity of Brn3.1, another transcription factor that controls the further differentiation and survival of auditory hair cells. Taken together, our data suggest that SHH plays an important role in the promotion of auditory hair cell differentiation via the Math1-Brn3.1 signaling pathway.

  1. Semicircular canals circumvent Brownian Motion overload of mechanoreceptor hair cells

    DEFF Research Database (Denmark)

    Muller, Mees; Heeck, Kier; Elemans, Coen P H

    2016-01-01

    Vertebrate semicircular canals (SCC) first appeared in the vertebrates (i.e. ancestral fish) over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as compared to cochlear hair cells are distinctly longer (70 vs. 7 μm), 10 times more compliant to bending (44 vs. 500...... nN/m), and have a 100-fold higher tip displacement threshold (hair cells where the bundle is approximated as a stiff, cylindrical elastic rod subject to friction and thermal agitation. Our models suggest that the above...... differences aid SCC hair cells in circumventing the masking effects of Brownian motion noise of about 70 nm, and thereby permit transduction of very low frequency (

  2. A study on the cochlear view in multichannel cochlear implantees

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, Dae Cheol; Kim, Jeong Hee; Kim, Seong Lyong; Kim, Hae Seong; Lee, Yong Woo [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    1999-04-01

    Cochlear implant poses a contraindication to the magnetic resonance imaging(MRI) process, because MRI generates artifacts, inducing an electrical current and causing device magnetization. CT is relatively expensive and the metal electrodes scatter the image. Post-implantation radiological studies using anterior-posterior transorbital, submental-vertex and lateral views, the intracochlear electrodes are not well displayed. Therefore, the authors developed a special view, which we call the cochlear view. The patient is sitting in front of a vertical device. Then the midsagittal plane is adjusted to form an angle of 15 .deg. , 30 .deg. , and 45 .deg. with the film. The flexion of the neck is adjusted to make the infraorbitomeatal line(IOML) is parallel with the transverse axis of the film. The central ray is directed to exit from the skull at point which is 3.0 cm anterior and 2.0 cm superior to the EAM(external auditory meatus). Results have shown that single radiography of the cochlear view provides sufficient information to demonstrate the position of the electrodes array and the depth of insertion in cochlear. Radiography of the cochlear view in angle of 45 .deg. is an excellent image. The cochlear view gives the greatest amount of medical information with the least radiation and lowest medical cost. It can be widely used in all cochlear implant clinics.

  3. Reduction in noise-induced functional loss of the cochleae in mice with pre-existing cochlear dysfunction due to genetic interference of prestin.

    Science.gov (United States)

    Cai, Qunfeng; Wang, Bo; Coling, Donald; Zuo, Jian; Fang, Jie; Yang, Shiming; Vera, Krystal; Hu, Bo Hua

    2014-01-01

    Various cochlear pathologies, such as acoustic trauma, ototoxicity and age-related degeneration, cause hearing loss. These pre-existing hearing losses can alter cochlear responses to subsequent acoustic overstimulation. So far, the knowledge on the impacts of pre-existing hearing loss caused by genetic alteration of cochlear genes is limited. Prestin is the motor protein expressed exclusively in outer hair cells in the mammalian cochlea. This motor protein contributes to outer hair cell motility. At present, it is not clear how the interference of prestin function affects cochlear responses to acoustic overstimulation. To address this question, a genetic model of prestin dysfunction in mice was created by inserting an internal ribosome entry site (IRES)-CreERT2-FRT-Neo-FRT cassette into the prestin locus after the stop codon. Homozygous mice exhibit a threshold elevation of auditory brainstem responses with large individual variation. These mice also display a threshold elevation and a shift of the input/output function of the distortion product otoacoustic emission, suggesting a reduction in outer hair cell function. The disruption of prestin function reduces the threshold shifts caused by exposure to a loud noise at 120 dB (sound pressure level) for 1 h. This reduction is positively correlated with the level of pre-noise cochlear dysfunction and is accompanied by a reduced change in Cdh1 expression, suggesting a reduction in molecular responses to the acoustic overstimulation. Together, these results suggest that prestin interference reduces cochlear stress responses to acoustic overstimulation.

  4. Female Pattern Hair Loss

    Science.gov (United States)

    ... are signs of hormone imbalance, such as excess facial or body hair, a hormone evaluation should be done. Hormonal changes are a common cause of female hair loss. Many women do not realize that hair loss can occur ...

  5. COCHLEAR IMPLANTATION PREVALENCE IN ELDERLY

    Directory of Open Access Journals (Sweden)

    A. V. Starokha

    2014-01-01

    Full Text Available Current paper describes an experience of cochlear implantation in elderly. Cochlear implantation has become a widely accepted intervention in the treatment of individuals with severe-to-profound sensorineural hearing loss. Cochlear implants are now accepted as a standard of care to optimize hearing and subsequent speech development in children and adults with deafness. But cochlear implantation affects not only hearing abilities, speech perception and speech production; it also has an outstanding impact on the social life, activities and self-esteem of each patient. The aim of this study was to evaluate the cochlear implantation efficacy in elderly with severe to profound sensorineural hearing loss. There were 5 patients under our observation. Surgery was performed according to traditional posterior tympanotomy and cochleostomy for cochlear implant electrode insertion for all observed patients. The study was conducted in two stages: before speech processor’s activation and 3 months later. Pure tone free field audiometry was performed to each patient to assess the efficiency of cochlear implantation in dynamics. The aim of the study was also to evaluate quality of life in elderly with severe to profound sensorineural hearing loss after unilateral cochlear implantation. Each patient underwent questioning with 36 Item Short Form Health Survey (SF-36. SF-36 is a set of generic, coherent, and easily administered quality-of-life measures. The SF-36 consists of eight scaled scores, which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. The eight sections are: physical functioning; physical role functioning; emotional role functioning; vitality; emotional well-being; social role functioning; bodily pain; general health perceptions. Our results demonstrate that cochlear implantation in elderly consistently improved quality of life

  6. Hair dye poisoning

    Science.gov (United States)

    Hair tint poisoning ... Different types of hair dye contain different harmful ingredients. The harmful ingredients in permanent dyes are: Naphthylamine Other aromatic amino compounds Phenylenediamines Toluene ...

  7. [Neurotology and cochlear implants].

    Science.gov (United States)

    Merchán, Miguel A

    2015-05-01

    In this review we analyse cochlear implantation in terms of the fundamental aspects of the functioning of the auditory system. Concepts concerning neuronal plasticity applied to electrical stimulation in perinatal and adult deep hypoacusis are reviewed, and the latest scientific bases that justify early implantation following screening for congenital deafness are discussed. Finally, this review aims to serve as an example of the importance of fostering the sub-specialty of neurotology in our milieu, with the aim of bridging some of the gaps between specialties and thus improving both the knowledge in the field of research on auditory pathologies and in the screening of patients. The objectives of this review, targeted above all towards specialists in the field of otorhinolaryngology, are to analyse some significant neurological foundations in order to reach a better understanding of the clinical events that condition the indications and the rehabilitation of patients with cochlear implants, as well as to use this means to foster the growth of the sub-specialty of neurotology.

  8. Hair Loss in New Moms

    Science.gov (United States)

    ... gently cut the hair, such as a small knife or scissors. If you cannot remove the hair ... and temporary hair shedding. Hair styling without damage Making some simple changes to your hair care can ...

  9. A Physiological Signal Transmission Model to be Used for Specific Diagnosis of Cochlear Impairments

    Science.gov (United States)

    Saremi, Amin; Stenfelt, Stefan

    2011-11-01

    Many of the sophisticated characteristics of human auditory system are attributed to cochlea. Also, most of patients with a hearing loss suffer from impairments that originate from cochlea (sensorineural). Despite this, today's clinical diagnosis methods do not probe the specific origins of such cochlear lesions. The aim of this research is to introduce a physiological signal transmission model to be clinically used as a tool for diagnosis of cochlear losses. This model enables simulation of different bio-mechano-electrical processes which occur in the auditory organ of Corti inside the cochlea. What makes this model different from many available computational models is its loyalty to physiology since the ultimate goal is to model each single physiological phenomenon. This includes passive BM vibration, outer hair cells' performances such as nonlinear mechanoelectrical transduction (MET), active amplifications by somatic motor, as well as vibration to neural conversion at the inner hair cells.

  10. Immediate and delayed cochlear neuropathy after noise exposure in pubescent mice.

    Directory of Open Access Journals (Sweden)

    Jane Bjerg Jensen

    Full Text Available Moderate acoustic overexposure in adult rodents is known to cause acute loss of synapses on sensory inner hair cells (IHCs and delayed degeneration of the auditory nerve, despite the completely reversible temporary threshold shift (TTS and morphologically intact hair cells. Our objective was to determine whether a cochlear synaptopathy followed by neuropathy occurs after noise exposure in pubescence, and to define neuropathic versus non-neuropathic noise levels for pubescent mice. While exposing 6 week old CBA/CaJ mice to 8-16 kHz bandpass noise for 2 hrs, we defined 97 dB sound pressure level (SPL as the threshold for this particular type of neuropathic exposure associated with TTS, and 94 dB SPL as the highest non-neuropathic noise level associated with TTS. Exposure to 100 dB SPL caused permanent threshold shift although exposure of 16 week old mice to the same noise is reported to cause only TTS. Amplitude of wave I of the auditory brainstem response, which reflects the summed activity of the cochlear nerve, was complemented by synaptic ribbon counts in IHCs using confocal microscopy, and by stereological counts of peripheral axons and cell bodies of the cochlear nerve from 24 hours to 16 months post exposure. Mice exposed to neuropathic noise demonstrated immediate cochlear synaptopathy by 24 hours post exposure, and delayed neurodegeneration characterized by axonal retraction at 8 months, and spiral ganglion cell loss at 8-16 months post exposure. Although the damage was initially limited to the cochlear base, it progressed to also involve the cochlear apex by 8 months post exposure. Our data demonstrate a fine line between neuropathic and non-neuropathic noise levels associated with TTS in the pubescent cochlea.

  11. Fibro-Vascular Coupling in the Control of Cochlear Blood Flow

    OpenAIRE

    Min Dai; Xiaorui Shi

    2011-01-01

    BACKGROUND: Transduction of sound in the cochlea is metabolically demanding. The lateral wall and hair cells are critically vulnerable to hypoxia, especially at high sound levels, and tight control over cochlear blood flow (CBF) is a physiological necessity. Yet despite the importance of CBF for hearing, consensus on what mechanisms are involved has not been obtained. METHODOLOGY/PRINCIPAL FINDINGS: We report on a local control mechanism for regulating inner ear blood flow involving fibrocyte...

  12. Profile of cochlear implant users of the city of Manaus

    Science.gov (United States)

    Pedrett, Mariana dos Santos; Moreira, Sandra Costa

    2012-01-01

    Summary Introduction: The cochlear implant is a device that is intended to substitute for the function of cochlear hair cells, electrically stimulate auditory nerve fibers, and contribute to the perception of speech sounds. However, the surgical procedure alone is not enough for the user to achieve favorable results in habilitation/rehabilitation. Objective: To characterize the patients from Manaus who have received cochlear implants based on the criteria for surgery. Methods: We conducted a retrospective cross-sectional study of 15 cases and recorded etiological aspects of deafness, age, gender, duration of implant use, use of hearing aids, and participation in individual therapy. Data were recorded in a protocol designed specifically for this purpose. All patients were natives of Manaus. Results: The leading etiological aspect was ototoxicity associated with prematurity in newborns undergoing treatment in the neonatal intensive care unit. The age at surgery is carefully observed in the evaluation of implant centers, as well as if the candidate is pre-or post-lingual. In this study, 73% of patients were pre-lingual and did not benefit from hearing aids. As to the degree and type of hearing loss, 93% had audiological reports indicating profound bilateral sensorineural hearing loss and 7% had severe bilateral sensorineural hearing loss. This latter finding confirmed one of the basic principles of implant placement. Conclusion: This study allowed us to verify that there are reduced number of cochlear implant recipients in Manaus, but they have met the criteria required by implant centers located in other states of Brazil. PMID:25991973

  13. Profile of cochlear implant users of the city of Manaus

    Directory of Open Access Journals (Sweden)

    Pedrett, Mariana dos Santos

    2012-01-01

    Full Text Available Introduction: The cochlear implant is a device that is intended to substitute for the function of cochlear hair cells, electrically stimulate auditory nerve fibers, and contribute to the perception of speech sounds. However, the surgical procedure alone is not enough for the user to achieve favorable results in habilitation/rehabilitation. Objective: To characterize the patients from Manaus who have received cochlear implants based on the criteria for surgery. Methods: We conducted a retrospective cross-sectional study of 15 cases and recorded etiological aspects of deafness, age, gender, duration of implant use, use of hearing aids, and participation in individual therapy. Data were recorded in a protocol designed specifically for this purpose. All patients were natives of Manaus. Results: The leading etiological aspect was ototoxicity associated with prematurity in newborns undergoing treatment in the neonatal intensive care unit. The age at surgery is carefully observed in the evaluation of implant centers, as well as if the candidate is pre-or post-lingual. In this study, 73% of patients were pre-lingual and did not benefit from hearing aids. As to the degree and type of hearing loss, 93% had audiological reports indicating profound bilateral sensorineural hearing loss and 7% had severe bilateral sensorineural hearing loss. This latter finding confirmed one of the basic principles of implant placement. Conclusion: This study allowed us to verify that there are reduced number of cochlear implant recipients in Manaus, but they have met the criteria required by implant centers located in other states of Brazil.

  14. Hair cosmetics: an overview.

    Science.gov (United States)

    Gavazzoni Dias, Maria Fernanda Reis

    2015-01-01

    Hair cosmetics are an important tool that helps to increase patient's adhesion to alopecia and scalp treatments. This article reviews the formulations and the mode of action of hair cosmetics: Shampoos, conditioners, hair straightening products, hair dyes and henna; regarding their prescription and safetiness. The dermatologist's knowledge of hair care products, their use, and their possible side effects can extend to an understanding of cosmetic resources and help dermatologists to better treat hair and scalp conditions according to the diversity of hair types and ethnicity.

  15. The effects of oxidative damage induced by organic oxidant t-BHP on cochlear hair cells%叔丁基过氧化氢体外模拟噪声引起的耳蜗毛细胞氧化损伤模型的建立

    Institute of Scientific and Technical Information of China (English)

    陈利梅; 郭晓; 李旭东; 王致; 刘移民

    2012-01-01

    Objective To establish the oxidative damage model of cochlea hair cells using organic oxidant t-BHP in vitro.Methods HEI-OC 1 cells were exposed to t-BHP at 8 doses (30~4000 μmol/L) for 12h.Trypan blue test was used to detected the cellular viability and MTT assay was utiilzed to measured the cellular proliferation.The intracellular ROS levels were determined by 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA).Results The survival rates of HEI-OC1 cells started decrease significantly at the dose of 100 μmol/L t-BHP,the peak of decreased survival rates appeared at the doses of 200~800 μ mol/L.The results of MTT assay demonstrated that 30 μmol/L t-BHP could promote cellular proliferation ability,when t-BHP concentrations were higher than 200 μmol/L,the cellular proliferation ability was inhibited.The results of DCFH-DA assay showed that there was no fluorescence in control group,the strong fluorescence was observed in positive control group,the weak fluorescence was observed in 30~50 μmol/L t-BHP groups,the bright fluorescence was observed in 100 μmol/L t-BHP group,still the stronger fluorescence was observed in 200~1000μmol/L groups,but the cellular number decreased with the doses because of the lower cellular viability.Conclusion The exposure to 100 μmol/L t-BHP for 12 h could simulate the oxidative damage induced by noise in cochlear hair cells.%目的 研究有机氧化剂叔丁基过氧化氢(t-BHP)体外模拟噪声对耳蜗毛细胞的氧化损伤.方法 用t-BHP染毒,设置从30~4000 μmol/L8个染毒浓度对耳蜗毛细胞(HEI-OC1)细胞染毒12h,绘制100 μmol/L浓度组染毒时间(1~96 h)与耳蜗毛细胞存活率曲线;采用台盼蓝染色法检测细胞存活率,噻唑蓝(MTT)试验检测细胞增殖能力的改变,2’-7’-二氯荧光黄双乙酯(DCFH-DA)探针法检测胞内活性氧(ROS)水平.结果 不同浓度的t-BHP对耳蜗毛细胞染毒12h后,100μmol/L以上浓度组细胞存活率开始出现有

  16. Effects of salicylate on sound-evoked outer hair cell stereocilia deflections.

    Science.gov (United States)

    Hakizimana, Pierre; Fridberger, Anders

    2015-09-01

    Hearing depends on sound-evoked deflections of the stereocilia that protrude from the sensory hair cells in the inner ear. Although sound provides an important force driving stereocilia, forces generated through mechanically sensitive ion channels and through the motor protein prestin have been shown to influence stereocilia motion in solitary hair cells. While a possible influence of prestin on mechanically sensitive ion channels has not been systematically investigated, a decrease in transducer currents is evident in solitary hair cells when prestin is blocked with salicylate, raising the question of whether a reduced prestin activity or salicylate itself affected the mechanotransduction apparatus. We used two- and three-dimensional time-resolved confocal imaging to visualize outer hair cell stereocilia during sound stimulation in the apical turn of cochlear explant preparations from the guinea pig. Surprisingly, following application of salicylate, outer hair cell stereocilia deflections increased, while cochlear microphonic potentials decreased. However, when prestin activity was altered with the chloride ionophore tributyltin, both the cochlear microphonic potential and the stereocilia deflection amplitude decreased. Neither positive nor negative current stimulation abolished the bundle movements in the presence of salicylate, indicating that the observed effects did not depend on the endocochlear potential. These data suggest that salicylate may alter the mechanical properties of stereocilia, decreasing their bending stiffness.

  17. Outcome of cochlear implantation in children with cochlear malformations.

    Science.gov (United States)

    Bille, Jesper; Fink-Jensen, Vibeke; Ovesen, Therese

    2015-03-01

    The objective of the study was the evaluation of outcomes of cochlear implantation (CI) in children with cochlear malformations. A retrospective case-control study was conducted in a tertiary referral centre. The patients were children with inner ear malformation judged by high-resolution computed tomography and magnetic resonance imaging treated with uni- or bilateral CI and a follow-up period of at least 3 years. They were matched with a control group of children operated for other reasons. The patients were operated by one of two surgeons using similar techniques including a standard perimodiolar electrode in all cases. The intervention was therapeutic and rehabilitative. The main outcome measures were category of auditory performance (CAP) and speech intelligibility rating (SIR). Eighteen children were diagnosed with cochlear malformations (12 % of children receiving CI). No statistical differences regarding CAP and SIR scores were found between the two groups. Only one child was diagnosed with a common cavity and performed below average. Children with auditory neuropathy performed beyond average. Children with cochlear malformations performed equally to children without malformation in the long term. Standard perimodiolar electrodes can be used despite cochlear malformations. The most important factors determining the outcome is the age of the child at the time of implantation and duration of hearing loss before CI. Awareness towards an increased risk of complications in case of inner ear malformations is recommended.

  18. Aging of hair.

    Science.gov (United States)

    Trüeb, Ralph M

    2005-06-01

    The appearance of hair plays an important role in people's overall physical appearance and self-perception. With today's increasing life expectation, the desire to look youthful plays a bigger role than ever. The hair care industry has become aware of this and also more capable to deliver active products that are directed toward meeting this consumer demand. The discovery of pharmacological targets and the development of safe and effective drugs also indicate strategies of the drug industry for maintenance of healthy and beautiful hair. Hair aging comprises weathering of the hair shaft and aging of the hair follicle. The latter manifests as decrease of melanocyte function or graying, and decrease in hair production in androgenetic and senescent alopecia. The scalp is also subject to intrinsic or physiologic aging and extrinsic aging caused by external factors. Intrinsic factors are related to individual genetic and epigenetic mechanisms with interindividual variation. Prototypes are familial premature graying and androgenetic alopecia. Extrinsic factors include ultraviolet radiation and smoking. Experimental evidence supports the hypothesis that oxidative stress plays a role in skin and hair aging. Topical anti-aging compounds for hair include humefactants, hair conditioners, photoprotectors, and antioxidants. Current available treatment modalities with proven efficacy for treatment of androgenetic alopecia are topical minoxidil, oral finasteride, and autologous hair transplantation. In the absence of another way to reverse hair graying, hair colorants are the mainstays of recovering lost hair color. Topical liposome targeting for melanins, genes, and proteins selectively to hair follicles are under current investigation.

  19. Regeneration of stereocilia of hair cells by forced Atoh1 expression in the adult mammalian cochlea.

    Directory of Open Access Journals (Sweden)

    Shi-Ming Yang

    Full Text Available The hallmark of mechanosensory hair cells is the stereocilia, where mechanical stimuli are converted into electrical signals. These delicate stereocilia are susceptible to acoustic trauma and ototoxic drugs. While hair cells in lower vertebrates and the mammalian vestibular system can spontaneously regenerate lost stereocilia, mammalian cochlear hair cells no longer retain this capability. We explored the possibility of regenerating stereocilia in the noise-deafened guinea pig cochlea by cochlear inoculation of a viral vector carrying Atoh1, a gene critical for hair cell differentiation. Exposure to simulated gunfire resulted in a 60-70 dB hearing loss and extensive damage and loss of stereocilia bundles of both inner and outer hair cells along the entire cochlear length. However, most injured hair cells remained in the organ of Corti for up to 10 days after the trauma. A viral vector carrying an EGFP-labeled Atoh1 gene was inoculated into the cochlea through the round window on the seventh day after noise exposure. Auditory brainstem response measured one month after inoculation showed that hearing thresholds were substantially improved. Scanning electron microscopy revealed that the damaged/lost stereocilia bundles were repaired or regenerated after Atoh1 treatment, suggesting that Atoh1 was able to induce repair/regeneration of the damaged or lost stereocilia. Therefore, our studies revealed a new role of Atoh1 as a gene critical for promoting repair/regeneration of stereocilia and maintaining injured hair cells in the adult mammal cochlea. Atoh1-based gene therapy, therefore, has the potential to treat noise-induced hearing loss if the treatment is carried out before hair cells die.

  20. Therapeutic potential of stem cells in auditory hair cell repair

    Directory of Open Access Journals (Sweden)

    Ryuji Hata

    2009-01-01

    Full Text Available The prevalence of acquired hearing loss is very high. About 10% of the total population and more than one third of the population over 65 years suffer from debilitating hearing loss. The most common type of hearing loss in adults is idiopathic sudden sensorineural hearing loss (ISSHL. In the majority of cases, ISSHL is permanent and typically associated with loss of sensory hair cells in the organ of Corti. Following the loss of sensory hair cells, the auditory neurons undergo secondary degeneration. Sensory hair cells and auditory neurons do not regenerate throughout life, and loss of these cells is irreversible and cumulative. However, recent advances in stem cell biology have gained hope that stem cell therapy comes closer to regenerating sensory hair cells in humans. A major advance in the prospects for the use of stem cells to restore normal hearing comes with the recent discovery that hair cells can be generated ex vivo from embryonic stem (ES cells, adult inner ear stem cells and neural stem cells. Furthermore, there is increasing evidence that stem cells can promote damaged cell repair in part by secreting diffusible molecules such as growth factors. These results suggest that stem-cell-based treatment regimens can be applicable to the damaged inner ear as future clinical applications.Previously we have established an animal model of cochlear ischemia in gerbils and showed progressive hair cell loss up to 4 days after ischemia. Auditory brain stem response (ABR recordings have demonstrated that this gerbil model displays severe deafness just after cochlear ischemia and gradually recovers thereafter. These pathological findings and clinical manifestations are reminiscent of ISSHL in humans. In this study, we have shown the effectiveness of stem cell therapy by using this animal model of ISSHL.

  1. Cochlear Responses and Auditory Brainstem Response Functions in Adults with Auditory Neuropathy/ Dys-Synchrony and Individuals with Normal Hearing

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2007-06-01

    Full Text Available Background and Aim: Physiologic measures of cochlear and auditory nerve function may be of assis¬tance in distinguishing between hearing disorders due primarily to auditory nerve impairment from those due primarily to cochlear hair cells dysfunction. The goal of present study was to measure of co-chlear responses (otoacoustic emissions and cochlear microphonics and auditory brainstem response in some adults with auditory neuropathy/ dys-synchrony and subjects with normal hearing. Materials and Methods: Patients were 16 adults (32 ears in age range of 14-30 years with auditory neu¬ropathy/ dys-synchrony and 16 individuals in age range of 16-30 years from both sexes. The results of transient otoacoustic emissions, cochlear microphonics and auditory brainstem response measures were compared in both groups and the effects of age, sex, ear and degree of hearing loss were studied. Results: The pure-tone average was 48.1 dB HL in auditory neuropathy/dys-synchrony group and the fre¬quency of low tone loss and flat audiograms were higher among other audiogram's shapes. Transient oto¬acoustic emissions were shown in all auditory neuropathy/dys-synchrony people except two cases and its average was near in both studied groups. The latency and amplitude of the biggest reversed co-chlear microphonics response were higher in auditory neuropathy/dys-synchrony patients than control peo¬ple significantly. The correlation between cochlear microphonics amplitude and degree of hearing loss was not significant, and age had significant effect in some cochlear microphonics measures. Audi-tory brainstem response had no response in auditory neuropathy/dys-synchrony patients even with low stim¬uli rates. Conclusion: In adults with speech understanding worsen than predicted from the degree of hearing loss that suspect to auditory neuropathy/ dys-synchrony, the frequency of low tone loss and flat audiograms are higher. Usually auditory brainstem response is absent in

  2. Biomaterials in cochlear implants

    Directory of Open Access Journals (Sweden)

    Lenarz, Thomas

    2009-01-01

    Full Text Available The cochlear implant (CI represents, for almost 25 years now, the gold standard in the treatment of children born deaf and for postlingually deafened adults. These devices thus constitute the greatest success story in the field of ‘neurobionic’ prostheses. Their (now routine fitting in adults, and especially in young children and even babies, places exacting demands on these implants, particularly with regard to the biocompatibility of a CI’s surface components. Furthermore, certain parts of the implant face considerable mechanical challenges, such as the need for the electrode array to be flexible and resistant to breakage, and for the implant casing to be able to withstand external forces. As these implants are in the immediate vicinity of the middle-ear mucosa and of the junction to the perilymph of the cochlea, the risk exists – at least in principle – that bacteria may spread along the electrode array into the cochlea. The wide-ranging requirements made of the CI in terms of biocompatibility and the electrode mechanism mean that there is still further scope – despite the fact that CIs are already technically highly sophisticated – for ongoing improvements to the properties of these implants and their constituent materials, thus enhancing the effectiveness of these devices. This paper will therefore discuss fundamental material aspects of CIs as well as the potential for their future development.

  3. Microengineered hydromechanical cochlear model.

    Science.gov (United States)

    White, Robert D; Grosh, Karl

    2005-02-01

    Micromachined fluid-filled variable impedance waveguides intended to mimic the mechanics of the passive mammalian cochlea have been fabricated and experimentally examined. The structures were microfabricated with dimensions similar to those of the biological system. Experimental tests demonstrate acoustically excited traveling fluid-structure waves with phase accumulations between 1.5 and 3 pi radians at the location of maximum response. The resulting measured frequency-position mapping function, with similarities to that observed in the cochlea, is presented. Results for both isotropic and orthotropic membranes are reported, demonstrating that the achieved orthotropy ratio of 8:1 in tension is insufficient to produce the sharp filtering observed in animal experiments and many computational models that use higher ratios. It is also shown experimentally that high viscosity fluids must be used to provide sufficient damping to avoid the formation of a nonphysiological standing wave pattern. A mathematical model incorporating a thin-layer viscous, compressible fluid approximation coupled to an orthotropic membrane model is validated against experimental results. The work presented herein is motivated by the possibility of producing microfabricated cochlear-like filters, thus the structure is designed for production in a scalable microfabrication process.

  4. Congenitally Deafblind Children and Cochlear Implants

    DEFF Research Database (Denmark)

    Dammeyer, Jesper Herup

    2008-01-01

    There has been much research conducted demonstrating the positive benefits of cochlear implantation (CI) in children who are deaf. Research on cochlear implantation in children who are both deaf and blind, however, is lacking. The purpose of this article is to present a study of 5 congenitally...... deafblind children who received cochlear implants between 2.2 and 4.2 years of age.  Ratings of video observations were used to measure the children's early communication development with and without the use of their cochlear implants. In addition, parental interviews were used to assess the benefits...... parents perceived regarding their children's cochlear implants. Two examples are included in this article to illustrate the parents' perspectives about cochlear implantation in their deafblind children. Benefits of cochlear implantation in this cohort of children included improved attention and emotional...

  5. Experimental toxoplasmosis in broiler chicks.

    Science.gov (United States)

    Kaneto, C N; Costa, A J; Paulillo, A C; Moraes, F R; Murakami, T O; Meireles, M V

    1997-05-01

    To evaluate chicken toxoplasmosis both as an economic and a public health subject, 84 broiler chicks of a commercial strain, 30 days old, were distributed into seven groups of 12 birds (three replications of four chicks) experimentally infected with three developing T. gondii stages of the P strain as follows: tachyzoites, intravenous (two groups: 5.0 x 10(5) and 5.0 x 10(6)), cysts, per os (two groups: 1.0 x 10(2) and 1.0 x 10(3)) and oocysts, per os (three groups: 5.0 x 10(2), 5.0 x 10(3) and 5.0 x 10(4)). Twelve chicks received only a placebo (control group). During the next 30 days the following parameters were estimated: productivity (weight gain and feed conversion), clinical signs, including rectal temperature and parasitemia (bioassay). No clinical signs suggesting toxoplasmosis were seen and no statistical differences on productivity standards were found in comparison between inoculated and control chicks. However, fowls inoculated with tachyzoites and oocysts occasionally showed hyperthermia. Some haematological changes were detected in fowls inoculated with T. gondii. Anatomo-histopathological changes were not observed. From 14 parasitemias detected, 35.7% appeared on the 5th day after inoculation and 57.1% of them resulted from oocysts inoculation. After 30-35 days all birds were slaughtered: fragments from 12 organs or tissues from each of them were subjected to artificial peptic digestion and after that injected into T. gondii antibody-free mice (IIFR). T. gondii was detected in brain (12), pancreas (five), spleen (five), retina (five), kidney (two), heart (four), proventriculus (three), liver (two), intestine (two), lung (one), and skeletal muscle (one). Similar to observations with parasitemia, from 42 T. gondii isolations, 59.5% came from chicks which had received oocysts. It can thus be inferred that the developing form, expelled by cats, is the most important for T. gondii chicken infection and that brain is the most infected organ in birds

  6. Hair removal in adolescence

    Directory of Open Access Journals (Sweden)

    Sandra Pereira

    2015-06-01

    Full Text Available Introduction: Due to hormonal stimulation during puberty, changes occur in hair type and distribution. In both sexes, body and facial unwanted hair may have a negative psychological impact on the teenager. There are several available methods of hair removal, but the choice of the most suitable one for each individual can raise doubts. Objective: To review the main methods of hair removal and clarify their indications, advantages and disadvantages. Development: There are several removal methods currently available. Shaving and depilation with chemicals products are temporary methods, that need frequent repetition, because hair removal is next to the cutaneous surface. The epilating methods in which there is full hair extraction include: epilation with wax, thread, tweezers, epilating machines, laser, intense pulsed light, and electrolysis. Conclusions: The age of beginning hair removal and the method choice must be individualized and take into consideration the skin and hair type, location, dermatological and endocrine problems, removal frequency, cost and personal preferences.

  7. Persistence, distribution, and impact of distinctly segmented microparticles on cochlear health following in vivo infusion.

    Science.gov (United States)

    Ross, Astin M; Rahmani, Sahar; Prieskorn, Diane M; Dishman, Acacia F; Miller, Josef M; Lahann, Joerg; Altschuler, Richard A

    2016-06-01

    Delivery of pharmaceuticals to the cochleae of patients with auditory dysfunction could potentially have many benefits from enhancing auditory nerve survival to protecting remaining sensory cells and their neuronal connections. Treatment would require platforms to enable drug delivery directly to the cochlea and increase the potential efficacy of intervention. Cochlear implant recipients are a specific patient subset that could benefit from local drug delivery as more candidates have residual hearing; and since residual hearing directly contributes to post-implantation hearing outcomes, it requires protection from implant insertion-induced trauma. This study assessed the feasibility of utilizing microparticles for drug delivery into cochlear fluids, testing persistence, distribution, biocompatibility, and drug release characteristics. To allow for delivery of multiple therapeutics, particles were composed of two distinct compartments; one containing polylactide-co-glycolide (PLGA), and one composed of acetal-modified dextran and PLGA. Following in vivo infusion, image analysis revealed microparticle persistence in the cochlea for at least 7 days post-infusion, primarily in the first and second turns. The majority of subjects maintained or had only slight elevation in auditory brainstem response thresholds at 7 days post-infusion compared to pre-infusion baselines. There was only minor to limited loss of cochlear hair cells and negligible immune response based on CD45+ immunolabling. When Piribedil-loaded microparticles were infused, Piribedil was detectable within the cochlear fluids at 7 days post-infusion. These results indicate that segmented microparticles are relatively inert, can persist, release their contents, and be functionally and biologically compatible with cochlear function and therefore are promising vehicles for cochlear drug delivery. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1510-1522, 2016.

  8. Using noncontact AFM frequency shifts to determine stereocilia bundle stiffness and tension in the developing cochlear sensory epithelium

    Science.gov (United States)

    Chadwick, Richard S.; Cartagena-Rivera, Alexander X.

    2015-12-01

    Measurement of frequency shifts of cantilevers having an attached microsphere oscillating at acoustic frequencies can be used to assess mechanical properties of cochlear structures. The method has already been reported for measuring elastic and viscous properties of the tectorial membrane. We describe here how the method can be used to examine other cochlear structures. Theory and formulas for relating hair bundle stiffness and tension in the developing cochlear sensory epithelium to measured frequency shifts are given to estimate the expected frequency shifts and show feasibility of the measurements. We show through a molecular model of myosin II located along the edges of confluent hexagons that myosin contractile forces are balanced by isotropic tension in the developing confluent sheet of cells.

  9. Boys With Long Hair

    Institute of Scientific and Technical Information of China (English)

    孙利英

    2005-01-01

    Long hair is popular among the young people.Even the boy students in high school join in this group.Some boy students would rather wear long hair,some even change their hair's color into golden,red,brown and pink.Why?

  10. Reading skills after cochlear implantation

    NARCIS (Netherlands)

    Vermeulen, Agnes Maria

    2007-01-01

    It has frequently been found that profoundly deaf children with conventional hearing aids have difficulties with the comprehension of written text. Cochlear Implants (CIs) were expected to enhance the reading comprehension of these profoundly deaf children because they provide auditory access to spo

  11. Cortical plasticity after cochlear implantation

    DEFF Research Database (Denmark)

    Petersen, B; Gjedde, A; Wallentin, M;

    2013-01-01

    The most dramatic progress in the restoration of hearing takes place in the first months after cochlear implantation. To map the brain activity underlying this process, we used positron emission tomography at three time points: within 14 days, three months, and six months after switch-on. Fifteen...

  12. Cochlear implantation in superficial siderosis.

    Science.gov (United States)

    Kim, Chong-Sun; Song, Jae-Jun; Park, Min-Hyun; Kim, Young Ho; Koo, Ja-Won

    2006-08-01

    Superficial siderosis (SS) of the central nervous system has been thought to be a rare condition that generates progressive hearing loss, ataxia, pyramidal signs, and dementia. The main cause of hearing loss by SS is thought to be neuronal. Because there is no histopathologic report of the human temporal bone in SS, there is a debate about the possibility of cochlear involvement. We present a 25-year-old man who was investigated for bilateral progressive sensorineural hearing loss and vestibular failure after head trauma. On brain MRI, SS of the central nervous system was detected. Distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) showed no response on both sides. However, integrity of the eighth nerve was proved by the electrical ABR test on the right side and the patient benefited significantly from cochlear implantation. The sensorineural hearing loss in SS seems to be related to cochlear damage as well as neuronal damage. So, cochlear implantation would be a hearing rehabilitation modality for the sensorineural hearing loss caused by SS.

  13. Cochlear implantation: a biomechanical prosthesis for hearing loss.

    Science.gov (United States)

    Yawn, Robert; Hunter, Jacob B; Sweeney, Alex D; Bennett, Marc L

    2015-01-01

    Cochlear implants are a medical prosthesis used to treat sensorineural deafness, and one of the greatest advances in modern medicine. The following article is an overview of cochlear implant technology. The history of cochlear implantation and the development of modern implant technology will be discussed, as well as current surgical techniques. Research regarding expansion of candidacy, hearing preservation cochlear implantation, and implantation for unilateral deafness are described. Lastly, innovative technology is discussed, including the hybrid cochlear implant and the totally implantable cochlear implant.

  14. Energy flow in passive and active 3D cochlear model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli; Steele, Charles [Department of Mechanical Engineering, Stanford University, Stanford, California (United States); Puria, Sunil [Department of Mechanical Engineering, Stanford University, Stanford, California (United States); Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, California (United States)

    2015-12-31

    Energy flow in the cochlea is an important characteristic of the cochlear traveling wave, and many investigators, such as von Békésy and Lighthill, have discussed this phenomenon. Particularly after the discovery of the motility of the outer hair cells (OHCs), the nature of the power gain of the cochlea has been a fundamental research question. In the present work, direct three-dimensional (3D) calculations of the power on cross sections of the cochlea and on the basilar membrane are performed based on a box model of the mouse cochlea. The distributions of the fluid pressure and fluid velocity in the scala vestibuli are presented. The power output from the OHCs and the power loss due to fluid viscous damping are calculated along the length of the cochlea. This work provides a basis for theoretical calculations of the power gain of the OHCs from mechanical considerations.

  15. [Correlation of changes in compound action potential (CAP) tuning curves and cochlear lesion in guinea pigs after explosion].

    Science.gov (United States)

    Han, D

    1989-01-01

    The purpose of the present study was to investigate the sensitivity of compound action potential (CAP) tuning curves to changes of the cochlear status in guinea pigs after explosion and their ability to reflect specific histological variations. The results were as follows: 1. The CAP tuning curves were abnormally broad and the Q 10 dB values were reduced by a factor of 1 after explosion, indicating wider tuning. 2. The degree of broadening of the CAP tuning curves seemed to increase as the hair cell loss increased. 3. After explosion, the tip of the tuning curve shifted to frequencies significantly higher or lower than that of the signal, it might be related to the location of hair cell loss in the cochlea. 4. In animals for which damage was restricted to only three rows of outer hair cells, changes of the CAP tuning curves were observed. It provides further evidence that the tuning properties of cochlear nerve fibers are dependent upon the integrity of the outer hair cells even though the great majority of fibers innervate inner hair cells only.

  16. Cochlear compression: effects of low-frequency biasing on quadratic distortion product otoacoustic emission.

    Science.gov (United States)

    Bian, Lin

    2004-12-01

    Distortion product otoacoustic emissions (DPOAEs) are generated from the nonlinear transduction n cochlear outer hair cells. The transducer function demonstrating a compressive nonlinearity can be estimated from low-frequency modulation of DPOAEs. Experimental results from the gerbils showed that the magnitude of quadratic difference tone (QDT, f2-f1) was either enhanced or suppressed depending on the phase of the low-frequency bias tone. Within one period of the bias tone, QDT magnitudes exhibited two similar modulation patterns, each resembling the absolute value of the second derivative of the transducer function. In the time domain, the center notches of the modulation patterns occurred around the zero crossings of the bias pressure, whereas peaks corresponded to the increase or decrease in bias pressure. Evaluated with respect to the bias pressure, modulated QDT magnitude displayed a double-modulation pattern marked by a separation of the center notches. Loading/unloading of the cochlear transducer or rise/fall in bias pressure shifted the center notch to positive or negative sound pressures, indicating a mechanical hysteresis. These results suggest that QDT arises from the compression that coexists with the active hysteresis in cochlear transduction. Modulation of QDT magnitude reflects the dynamic regulation of cochlear transducer gain and compression.

  17. Hair dye contact allergy

    DEFF Research Database (Denmark)

    Søsted, Heidi; Rastogi, Suresh Chandra; Andersen, Klaus Ejner

    2004-01-01

    Colouring of hair can cause severe allergic contact dermatitis. The most frequently reported hair dye allergens are p-phenylenediamine (PPD) and toluene-2,5-diamine, which are included in, respectively, the patch test standard series and the hairdressers series. The aim of the present study...... was to identify dye precursors and couplers in hair dyeing products causing clinical hair dye dermatitis and to compare the data with the contents of these compounds in a randomly selected set of similar products. The patient material comprised 9 cases of characteristic clinical allergic hair dye reaction, where...... exposure history and patch testing had identified a specific hair dye product as the cause of the reaction. The 9 products used by the patients were subjected to chemical analysis. 8 hair dye products contained toluene-2,5-diamine (0.18 to 0.98%). PPD (0.27%) was found in 1 product, and m-aminophenol (0...

  18. Anatomic considerations of cochlear morphology and its implications for insertion trauma in cochlear implant surgery.

    NARCIS (Netherlands)

    Verbist, B.M.; Ferrarini, L.; Briaire, J.J.; Zarowski, A.; Admiraal-Behloul, F.; Olofsen, H.; Reiber, J.H.C.; Frijns, J.H.

    2009-01-01

    HYPOTHESIS: The goal of this study is to analyze the 3-dimensional anatomy of the cochlear spiral and to investigate the consequences of its course to insertion trauma during cochlear implantation. BACKGROUND: Insertion trauma in cochlear implant surgery is a feared surgical risk, potentially causin

  19. THE COCHlEAR RIBBON SYNAPTIC RESPONSE TO AMINOGIYCOSIDE OTOTOXICITY IN C57BL/6J MICE

    Institute of Scientific and Technical Information of China (English)

    LIU Ke; ZHAO Ning; SHI Chuang; WU Nan; LIU Huizhan; ZHANG Yue; YANG Weiyan; YANG Shiming

    2014-01-01

    Objective To investigate the early change of cochlear ribbon synapses on inner hair cells in response to aminoglycoside ototoxicity. Methods C57BL/6J mice received intraperitoneal injection of gentamicin (100 mg/kg/day), and the apical coil organ of Corti was examined on the 4th, 7th and 10th day (n=10). Litter-mates without gentamicin treatment served as controls (n=10). RIBEYE on the presynaptic membrane and AMPA receptors on the postsynaptic membrane were labeled with CtBP2 or GluR2/3 respectively. Three di-mension reconstruction was conducted using the 3DS MAX 8.0 software. Results There were no disruptions of outer or inner hair cells in all groups. However, the number of ribbon synapses on cochlear inner hair cells increased significantly within 7 days after gentamicin exposure (P<0.01), followed by a significant de-crease after 7 days.Conclusion During the early stage of aminoglycoside ototoxicity, increased population of cochlear ribbon synapses may indicate a significant down-regulation of synaptic function.

  20. Semicircular Canals Circumvent Brownian Motion Overload of Mechanoreceptor Hair Cells.

    Directory of Open Access Journals (Sweden)

    Mees Muller

    Full Text Available Vertebrate semicircular canals (SCC first appeared in the vertebrates (i.e. ancestral fish over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as compared to cochlear hair cells are distinctly longer (70 vs. 7 μm, 10 times more compliant to bending (44 vs. 500 nN/m, and have a 100-fold higher tip displacement threshold (< 10 μm vs. <400 nm. We have developed biomechanical models of vertebrate hair cells where the bundle is approximated as a stiff, cylindrical elastic rod subject to friction and thermal agitation. Our models suggest that the above differences aid SCC hair cells in circumventing the masking effects of Brownian motion noise of about 70 nm, and thereby permit transduction of very low frequency (<10 Hz signals. We observe that very low frequency mechanoreception requires increased stimulus amplitude, and argue that this is adaptive to circumvent Brownian motion overload at the hair bundles. We suggest that the selective advantage of detecting such low frequency stimuli may have favoured the evolution of large guiding structures such as semicircular canals and otoliths to overcome Brownian Motion noise at the level of the mechanoreceptors of the SCC.

  1. Cochlear implant in incomplete partition type I.

    Science.gov (United States)

    Berrettini, S; Forli, F; De Vito, A; Bruschini, L; Quaranta, N

    2013-02-01

    In this investigation, we report on 4 patients affected by incomplete partition type I submitted to cochlear implant at our institutions. Preoperative, surgical, mapping and follow-up issues as well as results in cases with this complex malformation are described. The cases reported in the present study confirm that cochlear implantation in patients with incomplete partition type I may be challenging for cochlear implant teams. The results are variable, but in many cases satisfactory, and are mainly related to the surgical placement of the electrode and residual neural nerve fibres. Moreover, in some cases the association of cochlear nerve abnormalities and other disabilities may significantly affect results.

  2. [Our experience with bilateral cochlear implantation].

    Science.gov (United States)

    Carmel, Eldar; Taitelbaum-Swead, Ricky; Migirov, Lela; Hildesheimer, Minka; Kronenberg, Jona

    2008-03-01

    Cochlear implantation is a standard method of hearing rehabilitation among patients with severe to profound bilateral sensorineural hearing loss. In recent years there have been an increasing number of studies showing superior hearing with bilateral cochlear implantation in comparison with a unilateral procedure. In this study we present our experience with 15 patients, children and adults, who had bilateral cochlear implant surgery. Speech perception test results demonstrated a hearing benefit in bilateral cochlear implantation in comparison with a unilateral device, mainly by improvement in the identification of speech in noise tests.

  3. Surface biotechnology for refining cochlear implants.

    Science.gov (United States)

    Tan, Fei; Walshe, Peter; Viani, Laura; Al-Rubeai, Mohamed

    2013-12-01

    The advent of the cochlear implant is phenomenal because it is the first surgical prosthesis that is capable of restoring one of the senses. The subsequent rapid evolution of cochlear implants through increasing complexity and functionality has been synchronized with the recent advancements in biotechnology. Surface biotechnology has refined cochlear implants by directly influencing the implant–tissue interface. Emerging surface biotechnology strategies are exemplified by nanofibrous polymeric materials, topographical surface modification, conducting polymer coatings, and neurotrophin-eluting implants. Although these novel developments have received individual attention in the recent literature, the time has come to investigate their collective applications to cochlear implants to restore lost hearing.

  4. Deafness and cochlear fibrocyte alterations in mice deficient for the inner ear protein otospiralin.

    Science.gov (United States)

    Delprat, Benjamin; Ruel, Jérôme; Guitton, Matthieu J; Hamard, Ghyslaine; Lenoir, Marc; Pujol, Rémy; Puel, Jean-Luc; Brabet, Philippe; Hamel, Christian P

    2005-01-01

    In the cochlea, the mammalian auditory organ, fibrocytes of the mesenchymal nonsensory regions play important roles in cochlear physiology, including the maintenance of ionic and hydric components in the endolymph. Occurrence of human deafness in fibrocyte alterations underlines their critical roles in auditory function. We recently described a novel gene, Otos, which encodes otospiralin, a small protein of unknown function that is produced by the fibrocytes of the cochlea and vestibule. We now have generated mice with deletion of Otos and found that they show moderate deafness, with no frequency predominance. Histopathology revealed a degeneration of type II and IV fibrocytes, while hair cells and stria vascularis appeared normal. Together, these findings suggest that impairment of fibrocytes caused by the loss in otospiralin leads to abnormal cochlear physiology and auditory function. This moderate dysfunction may predispose to age-related hearing loss.

  5. Novel High Content Screen Detects Compounds That Promote Neurite Regeneration from Cochlear Spiral Ganglion Neurons.

    Science.gov (United States)

    Whitlon, Donna S; Grover, Mary; Dunne, Sara F; Richter, Sonja; Luan, Chi-Hao; Richter, Claus-Peter

    2015-11-02

    The bipolar spiral ganglion neurons (SGN) carry sound information from cochlear hair cells to the brain. After noise, antibiotic or toxic insult to the cochlea, damage to SGN and/or hair cells causes hearing impairment. Damage ranges from fiber and synapse degeneration to dysfunction and loss of cells. New interventions to regenerate peripheral nerve fibers could help reestablish transfer of auditory information from surviving or regenerated hair cells or improve results from cochlear implants, but the biochemical mechanisms to target are largely unknown. Presently, no drugs exist that are FDA approved to stimulate the regeneration of SGN nerve fibers. We designed an original phenotypic assay to screen 440 compounds of the NIH Clinical Collection directly on dissociated mouse spiral ganglia. The assay detected one compound, cerivastatin, that increased the length of regenerating neurites. The effect, mimicked by other statins at different optimal concentrations, was blocked by geranylgeraniol. These results demonstrate the utility of screening small compound libraries on mixed cultures of dissociated primary ganglia. The success of this screen narrows down a moderately sized library to a single compound which can be elevated to in-depth in vivo studies, and highlights a potential new molecular pathway for targeting of hearing loss drugs.

  6. Hair cosmetics and camouflage technics

    Directory of Open Access Journals (Sweden)

    Zahide Eriş Eken

    2014-06-01

    Full Text Available Hair is composed of a mixture of trace elements in small quantities, proteins, lipids and water. Proteins consist of helical polypeptide amino acid molecules. In the hair cells; polypeptide chains of keratin protein would be organized in filaments. In recent years, hair cosmetics showed a significant change and development. The content of shampoos which is used to cleanse the hair has enhanced significantly. Hair conditioner, hair styling products, pomades, brilliantine, and gloss sprays, hair protective products, camouflage products are most commonly used hair cosmetics. Hair shaping procedures are frequently applied.

  7. Circumferential ′ Woolly Hair Naevus

    Directory of Open Access Journals (Sweden)

    Thadeus J

    1998-01-01

    Full Text Available Woolly hair naevus presents as a circumscribed area of tightly coiled hair since birth, in an individual of non-negroid origin. We report a 10 year old boy of Indian origin who presented with woolly hair in the periphery of the scalp and normal straight hair in the center-mimicking a straight hair naevus.

  8. Growth patterns of Hawaiian Stilt chicks

    Science.gov (United States)

    Reed, J.M.; Gray, E.M.; Lewis, D.; Oring, L.W.; Coleman, R.; Burr, T.; Luscomb, P.

    1999-01-01

    We studied chick growth and plumage patterns in the endangered Hawaiian Stilt (Himantopus mexicanus knudseni). Body mass of captive chicks closely fit a Gompertz growth curve, revealing a growth coefficient (K) of 0.065 day-1 and point of inflection (T) of 17 days. When chicks fledged about 28 days after hatching, they weighed only 60% of adult body mass; at 42 d, birds still were only 75% of adult mass; culmen, tarsus, and wing chord at fledging also were less than adult size. This trend of continued growth to adult size after fledging is typical for most shorebirds. After hatching, captive chicks grew more rapidly than wild chicks, probably because of an unlimited food supply. We found no evidence for adverse effects of weather on the growth of wild chicks. As with other shorebirds, the tarsus started relatively long, with culmen and then wing chord growing more rapidly in later development. Tarsal and wing chord growth were sigmoidal, whereas culmen growth was linear. We describe plumage characteristics of weekly age classes of chicks to help researchers age birds in the wild.

  9. Surgical Complications of Cochlear Implantation

    Directory of Open Access Journals (Sweden)

    Basir Hashemi

    2010-03-01

    Full Text Available Cochlear implantation is a method used for the treatment ofpatients with profound hearing loss. This procedure may theaccompanied by some major or minor complications. Weevaluated the surgical complications of cochlear implantationin Fars province (south of Iran. A total of 150 patients withcochlear implantation were enrolled in the present study. Mostof the patients were pre-lingual children and most of our deviceswere nucleus prosthesis. We had three device failuresand four major complications, including one misplaced electrode,one case of meningitis, one case of foreign body reactionto suture and one case with extensive hematoma. Thesecomplications were managed successfully by surgical interventionor re-implantation. Facial nerve damage or woundbreakdown was not seen. Minor complications including smallhematoma, edema, stitch infection and dizziness were found in15 cases, which were managed medically. In our center, therate of minor complications was comparable to other centersin the world. But the rate of major surgical complications waslower than other centers.

  10. HAIR CELL-LIKE CELL GENERATION INDUCED BY NATURE CULTURE OF ADULT RAT AUDITORY EPITHELIUM

    Institute of Scientific and Technical Information of China (English)

    Liu Hui; Zhu Hongliang; Li Shengli; Yao Xiaobao; Wang Xiaoxia

    2006-01-01

    Objective To establish adult rat auditory epithelial cell culture and try to find precursor cells of auditory hair cells in vitro. Methods With refinement of culture media and techniques, cochlear sensory epithelial cells of adult rat were cultured. Immunocytochemistry and Bromodeoxyuridine (BrdU)labeling were used to detect properties and mitotic status of cultured cells. Results The cultured auditory epithelial cells showed a large, flat epithelial morphotype and expressed F-actin and cytokeratin, a subset of cells generated from auditory epithelium were labeled by calretinin, a specific marker of early hair cell. Conclusion Adult rat auditory epithelium can be induced to generate hair cell-like cells by nature culture, this phenomenon suggests that progenitor cells may exist in rat cochlea and they may give birth to new hair cells. Whether these progenitor cells are tissue specific stem cells is still need more study.

  11. Adaptation of mammalian auditory hair cell mechanotransduction is independent of calcium entry.

    Science.gov (United States)

    Peng, Anthony W; Effertz, Thomas; Ricci, Anthony J

    2013-11-20

    Adaptation is a hallmark of hair cell mechanotransduction, extending the sensory hair bundle dynamic range while providing mechanical filtering of incoming sound. In hair cells responsive to low frequencies, two distinct adaptation mechanisms exist, a fast component of debatable origin and a slow myosin-based component. It is generally believed that Ca(2+) entry through mechano-electric transducer channels is required for both forms of adaptation. This study investigates the calcium dependence of adaptation in the mammalian auditory system. Recordings from rat cochlear hair cells demonstrate that altering Ca(2+) entry or internal Ca(2+) buffering has little effect on either adaptation kinetics or steady-state adaptation responses. Two additional findings include a voltage-dependent process and an extracellular Ca(2+) binding site, both modulating the resting open probability independent of adaptation. These data suggest that slow motor adaptation is negligible in mammalian auditory cells and that the remaining adaptation process is independent of calcium entry.

  12. Imaging in cochlear implant patients [

    OpenAIRE

    Aschendorff, Antje

    2012-01-01

    [english] Imaging procedures are a mainstream tool in the daily ENT workflow. Cochlear Implant patients are representing a special population with specific demands for imaging. There are different imaging techniques available for pre-operative evaluation, surgery and postoperative controls with different indications and consequences. High-resolution computed tomography and magnetic resonance imaging are mainly used in the evaluation process. New procedures, as digital volume tomography, are i...

  13. Cloning and characterization of SK2 channel from chicken short hair cells.

    Science.gov (United States)

    Matthews, T M; Duncan, R K; Zidanic, M; Michael, T H; Fuchs, P A

    2005-06-01

    In the inner ear of birds, as in mammals, reptiles and amphibians, acetylcholine released from efferent neurons inhibits hair cells via activation of an apamin-sensitive, calcium-dependent potassium current. The particular potassium channel involved in avian hair cell inhibition is unknown. In this study, we cloned a small-conductance, calcium-sensitive potassium channel (gSK2) from a chicken cochlear library. Using RT-PCR, we demonstrated the presence of gSK2 mRNA in cochlear hair cells. Electrophysiological studies on transfected HEK293 cells showed that gSK2 channels have a conductance of approximately 16 pS and a half-maximal calcium activation concentration of 0.74+/-0.17 microM. The expressed channels were blocked by apamin (IC(50)=73.3+/-5.0 pM) and d-tubocurarine (IC(50)=7.6+/-1.0 microM), but were insensitive to charybdotoxin. These characteristics are consistent with those reported for acetylcholine-induced potassium currents of isolated chicken hair cells, suggesting that gSK2 is involved in efferent inhibition of chicken inner ear. These findings imply that the molecular mechanisms of inhibition are conserved in hair cells of all vertebrates.

  14. Laser hair removal pearls.

    Science.gov (United States)

    Tierney, Emily P; Goldberg, David J

    2008-03-01

    A number of lasers and light devices are now available for the treatment of unwanted hair. The goal of laser hair removal is to damage stem cells in the bulge of the follicle through the targeting of melanin, the endogenous chromophore for laser and light devices utilized to remove hair. The competing chromophores in the skin and hair, oxyhemoglobin and water, have a decreased absorption between 690 nm and 1000 nm, thus making this an ideal range for laser and light sources. Pearls of laser hair removal are presented in this review, focusing on four areas of recent development: 1 treatment of blond, white and gray hair; 2 paradoxical hypertrichosis; 3 laser hair removal in children; and 4 comparison of lasers and IPL. Laser and light-based technologies to remove hair represents one of the most exciting areas where discoveries by dermatologists have led to novel treatment approaches. It is likely that in the next decade, continued advancements in this field will bring us closer to the development of a more permanent and painless form of hair removal.

  15. Female hair restoration.

    Science.gov (United States)

    Unger, Robin H

    2013-08-01

    Female hair loss is a devastating issue for women that has only relatively recently been publicly acknowledged as a significant problem. Hair transplant surgery is extremely successful in correcting the most cosmetically problematic areas of alopecia. This article discusses the surgical technique of hair transplantation in women in detail, including pearls to reduce postoperative sequelae and planning strategies to ensure a high degree of patient satisfaction. A brief overview of some of the medical treatments found to be helpful in slowing or reversing female pattern hair loss is included, addressing the available hormonal and topical treatments.

  16. Glutamate co-transmission from developing medial nucleus of the trapezoid body - Lateral superior olive synapses is cochlear dependent in kanamycin-treated rats

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Ho [Institute of Tissue Regeneration Engineering (ITREN), Dankook University, San 29, Anseo-dong, Cheonan-si, Chungnam 330-714 (Korea, Republic of); Pradhan, Jonu [Department of Nanobio Medical Science, Dankook University, San 29, Anseo-dong, Cheonan-si, Chungnam 330-714 (Korea, Republic of); Maskey, Dhiraj; Park, Ki Sup [Department of Anatomy, College of Medicine, Dankook University, San 29, Anseo-dong, Cheonan-si, Chungnam 330-714 (Korea, Republic of); Hong, Sung Hwa [Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University, School of Medicine, 50, Irwon-dong, Gangnam-gu, Seoul 135-710 (Korea, Republic of); Suh, Myung-Whan [Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Dankook University, San 29, Anseo-dong, Cheonan-si, Chungnam 330-714 (Korea, Republic of); Kim, Myeung Ju, E-mail: mjukim99@dankook.ac.kr [Department of Anatomy, College of Medicine, Dankook University, San 29, Anseo-dong, Cheonan-si, Chungnam 330-714 (Korea, Republic of); Ahn, Seung Cheol, E-mail: ansil67@hanmail.net [Department of Physiology, College of Medicine, Dankook University, San 29, Anseo-dong, Cheonan-si, Chungnam 330-714 (Korea, Republic of)

    2011-02-11

    Research highlights: {yields} Glutamate co-transmission is enhanced in kanamycin-treated rats. {yields} VGLUT3 expression is increased in kanamycin-treated rats. {yields} GlyR expression is decreased in kanamycin-treated rats. {yields} GlyR, VGLUT3 expression patterns are asymmetric in unilaterally cochlear ablated rat. -- Abstract: Cochlear dependency of glutamate co-transmission at the medial nucleus of the trapezoid body (MNTB) - the lateral superior olive (LSO) synapses was investigated using developing rats treated with high dose kanamycin. Rats were treated with kanamycin from postnatal day (P) 3 to P8. A scanning electron microscopic study on P9 demonstrated partial cochlear hair cell damage. A whole cell voltage clamp experiment demonstrated the increased glutamatergic portion of postsynaptic currents (PSCs) elicited by MNTB stimulation in P9-P11 kanamycin-treated rats. The enhanced VGLUT3 immunoreactivities (IRs) in kanamycin-treated rats and asymmetric VGLUT3 IRs in the LSO of unilaterally cochlear ablated rats supported the electrophysiologic data. Taken together, it is concluded that glutamate co-transmission is cochlear-dependent and enhanced glutamate co-transmission in kanamycin-treated rats is induced by partial cochlear damage.

  17. Effects of NSAIDs on the Inner Ear: Possible Involvement in Cochlear Protection

    Directory of Open Access Journals (Sweden)

    Akira Hara

    2010-04-01

    Full Text Available Cyclooxygenase and lipoxygenase, two important enzymes involved in arachidonic acid metabolism, are major targets of non-steroidal anti-inflammatory drugs (NSAIDs. Recent investigations suggest that arachidonic cascades and their metabolites may be involved in maintaining inner ear functions. The excessive use of aspirin may cause tinnitus in humans and impairment of the outer hair cell functions in experimental animals. On the other hand, NSAIDs reportedly exhibit protective effects against various kinds of inner ear disorder. The present review summarizes the effects of NSAIDs on cochlear pathophysiology. NSAIDs are a useful ameliorative adjunct in the management of inner ear disorders.

  18. Importance of cochlear health for implant function.

    Science.gov (United States)

    Pfingst, Bryan E; Zhou, Ning; Colesa, Deborah J; Watts, Melissa M; Strahl, Stefan B; Garadat, Soha N; Schvartz-Leyzac, Kara C; Budenz, Cameron L; Raphael, Yehoash; Zwolan, Teresa A

    2015-04-01

    Amazing progress has been made in providing useful hearing to hearing-impaired individuals using cochlear implants, but challenges remain. One such challenge is understanding the effects of partial degeneration of the auditory nerve, the target of cochlear implant stimulation. Here we review studies from our human and animal laboratories aimed at characterizing the health of the implanted cochlea and the auditory nerve. We use the data on cochlear and neural health to guide rehabilitation strategies. The data also motivate the development of tissue-engineering procedures to preserve or build a healthy cochlea and improve performance obtained by cochlear implant recipients or eventually replace the need for a cochlear implant. This article is part of a Special Issue entitled .

  19. Cochlear implant in Hong Kong Cantonese.

    Science.gov (United States)

    Tang, S O; Luk, W S; Lau, C C; So, K W; Wong, C M; Yiu, M L; Kwok, C L

    1990-11-01

    Cochlear implant surgery was performed in four Cantonese-speaking postlingually deaf Chinese adults, using the House/3M single channel device. This article outlines the methodology, including preoperative assessment and postoperative rehabilitation; and explains the necessary modifications in speech and audiologic work-up in Cantonese-speaking patients. Salient features of Cantonese phonetics, especially its tonal characteristics, are described. The findings of the study are presented. The results of the cochlear implant would suggest a performance superior to that of the hearing aid. Furthermore, the cochlear implant is able to detect tonal cues. This quality of the cochlear implant may prove to be a valuable asset to a tonal language-speaking cochlear implantee.

  20. Diffuse heterochromia of scalp hair.

    Science.gov (United States)

    Lee, W S; Lee, I W; Ahn, S K

    1996-11-01

    Heterochromia of hair is the presence of more than one distinct color of hair in the same person. A color difference between scalp hair and a mustache or sideburns is not uncommon. Pubic and axillary hair and eyebrows and eyelashes are often darker than scalp hair in a fair-haired person. Rarely, a circumscribed patch of hair of different colors occurs. However, diffuse heterochromia of black and red scalp hair has not been previously reported. We describe a father and son with this condition.

  1. Anasarca and myopathy in ostrich chicks.

    Science.gov (United States)

    Philbey, A W; Button, C; Gestier, A W; Munro, B E; Glastonbury, J R; Hindmarsh, M; Love, S C

    1991-07-01

    Twenty ostrich chicks that died at, or within, 1 week after hatching were examined from 7 farms with poor (43 to 75%) hatchability. All chicks had anasarca and 15 had mild, generalised, acute degenerative changes in the complexus and pelvic limb muscles. One had fibrinoid degeneration of arterioles. Biochemical examinations produced no evidence of deficiencies of selenium, vitamin A or vitamin E. The syndrome was related to high relative humidity during incubation. Malpositioning also was a cause of embryo mortality.

  2. Hair and nail relationship.

    NARCIS (Netherlands)

    Baran, R.; Dawber, R.P.; Haneke, E.

    2005-01-01

    Hair and nails are often stated to have much in common in relation to their origin, anatomical structures, and common involvement in many diseases. Hair and nails are predominantly epithelial structures derived from primitive epidermis and made up of keratinous fibrils embedded in a sulfur-rich matr

  3. Help! It's Hair Loss!

    Science.gov (United States)

    ... los dientes Video: Getting an X-ray Help! It's Hair Loss! KidsHealth > For Kids > Help! It's Hair Loss! Print A A A What's in ... part above the skin, is dead. (That's why it doesn't hurt to get a haircut!) This ...

  4. 单次放射线照射早期Balb/c小鼠畸变产物耳声发射变化和耳蜗外毛细胞Prestin蛋白表达的实验观察%Experimental Observation of the Influence of Single-dose Radiation on the Distortion Product Otoacoustic Emission and the Prestin Expressions in the Cochlear Outer Hair Cells of Balb/c Mice in the Early Period after Radiation Exposure

    Institute of Scientific and Technical Information of China (English)

    赵向东; 梁勇; 任陈; 袁亚维

    2013-01-01

    Objective To study the effect of radiation exposure on the distortion product otoacoustic emission(DPOAE) and Prestin expression in the cochlear outer hair cells of Balb/c mice in the early period after single-dose radiation exposure and to examine the possible mechanism of radiation causing sensorineural hearing loss(SNHL). Methods The Balb/c mouse models with outer hair cells exposed to radiation were established. The DPOAE amplitudes of the mice were detected and compared before, 3 days and 7 days after exposure to a single dose of 16Gy radiation. The Western Blot and reverse transcription-polymerase chain reaction(RT-PCR) assays were used to analyze the changes of expression of Prestin and its mRNA in the cochleae of mice. Results The Balb/c mouse models with SNHL after radiation exposure were successfully established. The DPOAE amplitudes of the mice on the 3rd and 7th day after radiation exposure were lower than those before radiation exposure at 3,4,6,8,10 and 12 kHz and the amplitudes on the 7th day were lower than those on the 3rd day at most frequencies. The expressions of Prestin and its mRNA after radiation exposure were parallel down-regulated as compared with those before exposure and the expressions of Prestin and its mRNA on the 7th day after radiation exposure were lower than those on the 3rd day. Conclusion The auditory function of the mice was affected in the early period after radiation exposure. The mechanism of SNHL after radiation exposure may be correlated with Prestin expression abnormalities in the outer hair cells of cochleae in the early period after radiation exposure.%  目的探讨放射线照射早期对Balb/c小鼠畸变产物耳声发射(DPOAE)和耳蜗外毛细胞Prestin蛋白的影响及放射线照射导致感音神经性耳聋的可能机制。方法建立放疗早期感音神经性耳聋(sensorineural hearing loss,SNHL)Balb/c小鼠模型。检测一次性给予单侧耳总放射剂量为16 Gy的

  5. Excessive activation of ionotropic glutamate receptors induces apoptotic hair-cell death independent of afferent and efferent innervation

    Science.gov (United States)

    Sheets, Lavinia

    2017-01-01

    Accumulation of excess glutamate plays a central role in eliciting the pathological events that follow intensely loud noise exposures and ischemia-reperfusion injury. Glutamate excitotoxicity has been characterized in cochlear nerve terminals, but much less is known about whether excess glutamate signaling also contributes to pathological changes in sensory hair cells. I therefore examined whether glutamate excitotoxicity damages hair cells in zebrafish larvae exposed to drugs that mimic excitotoxic trauma. Exposure to ionotropic glutamate receptor (iGluR) agonists, kainic acid (KA) or N-methyl-D-aspartate (NMDA), contributed to significant, progressive hair cell loss in zebrafish lateral-line organs. To examine whether hair-cell loss was a secondary effect of excitotoxic damage to innervating neurons, I exposed neurog1a morphants—fish whose hair-cell organs are devoid of afferent and efferent innervation—to KA or NMDA. Significant, dose-dependent hair-cell loss occurred in neurog1a morphants exposed to either agonist, and the loss was comparable to wild-type siblings. A survey of iGluR gene expression revealed AMPA-, Kainate-, and NMDA-type subunits are expressed in zebrafish hair cells. Finally, hair cells exposed to KA or NMDA appear to undergo apoptotic cell death. Cumulatively, these data reveal that excess glutamate signaling through iGluRs induces hair-cell death independent of damage to postsynaptic terminals. PMID:28112265

  6. Activation of PI3K signaling prevents aminoglycoside-induced hair cell death in the murine cochlea

    Directory of Open Access Journals (Sweden)

    Azadeh Jadali

    2016-06-01

    Full Text Available Loss of sensory hair cells of the inner ear due to aminoglycoside exposure is a major cause of hearing loss. Using an immortalized multipotent otic progenitor (iMOP cell line, specific signaling pathways that promote otic cell survival were identified. Of the signaling pathways identified, the PI3K pathway emerged as a strong candidate for promoting hair cell survival. In aging animals, components for active PI3K signaling are present but decrease in hair cells. In this study, we determined whether activated PI3K signaling in hair cells promotes survival. To activate PI3K signaling in hair cells, we used a small molecule inhibitor of PTEN or genetically ablated PTEN using a conditional knockout animal. Hair cell survival was challenged by addition of gentamicin to cochlear cultures. Hair cells with activated PI3K signaling were more resistant to aminoglycoside-induced hair cell death. These results indicate that increased PI3K signaling in hair cells promote survival and the PI3K signaling pathway is a target for preventing aminoglycoside-induced hearing loss.

  7. Audiovisual segregation in cochlear implant users.

    Directory of Open Access Journals (Sweden)

    Simon Landry

    Full Text Available It has traditionally been assumed that cochlear implant users de facto perform atypically in audiovisual tasks. However, a recent study that combined an auditory task with visual distractors suggests that only those cochlear implant users that are not proficient at recognizing speech sounds might show abnormal audiovisual interactions. The present study aims at reinforcing this notion by investigating the audiovisual segregation abilities of cochlear implant users in a visual task with auditory distractors. Speechreading was assessed in two groups of cochlear implant users (proficient and non-proficient at sound recognition, as well as in normal controls. A visual speech recognition task (i.e. speechreading was administered either in silence or in combination with three types of auditory distractors: i noise ii reverse speech sound and iii non-altered speech sound. Cochlear implant users proficient at speech recognition performed like normal controls in all conditions, whereas non-proficient users showed significantly different audiovisual segregation patterns in both speech conditions. These results confirm that normal-like audiovisual segregation is possible in highly skilled cochlear implant users and, consequently, that proficient and non-proficient CI users cannot be lumped into a single group. This important feature must be taken into account in further studies of audiovisual interactions in cochlear implant users.

  8. Hair dyeing, hair washing and hair cortisol concentrations among women from the healthy start study

    DEFF Research Database (Denmark)

    Kristensen, Sheila K; Larsen, Sofus C; Olsen, Nanna J

    2016-01-01

    BACKGROUND: Hair cortisol concentration (HCC) has been suggested as a promising marker for chronic stress. However, studies investigating the influence of hair dyeing and hair washing frequency on HCC have shown inconsistent results. OBJECTIVE: To examine associations between HCC and hair dyeing...... status or weekly hair washing frequency among women. METHODS: This cross-sectional study was based on data from 266 mothers participating in the Healthy Start intervention study. HCC was measured in the proximal end of the hair (1-2cm closest to the scalp) while hair dyeing status, frequency of hair...... washing and covariates were reported by the women. Linear regression analyses were applied to assess the associations between HCC and hair dyeing or weekly frequency of hair washing. RESULTS: No statistically significant difference (p=0.91) in HCC was found between women who dyed hair (adjusted mean: 137...

  9. HCN channels are not required for mechanotransduction in sensory hair cells of the mouse inner ear.

    Directory of Open Access Journals (Sweden)

    Geoffrey C Horwitz

    Full Text Available The molecular composition of the hair cell transduction channel has not been identified. Here we explore the novel hypothesis that hair cell transduction channels include HCN subunits. The HCN family of ion channels includes four members, HCN1-4. They were originally identified as the molecular correlates of the hyperpolarization-activated, cyclic nucleotide gated ion channels that carry currents known as If, IQ or Ih. However, based on recent evidence it has been suggested that HCN subunits may also be components of the elusive hair cell transduction channel. To investigate this hypothesis we examined expression of mRNA that encodes HCN1-4 in sensory epithelia of the mouse inner ear, immunolocalization of HCN subunits 1, 2 and 4, uptake of the transduction channel permeable dye, FM1-43 and electrophysiological measurement of mechanotransduction current. Dye uptake and transduction current were assayed in cochlear and vestibular hair cells of wildtype mice exposed to HCN channel blockers or a dominant-negative form of HCN2 that contained a pore mutation and in mutant mice that lacked HCN1, HCN2 or both. We found robust expression of HCNs 1, 2 and 4 but little evidence that localized HCN subunits in hair bundles, the site of mechanotransduction. Although high concentrations of the HCN antagonist, ZD7288, blocked 50-70% of the transduction current, we found no reduction of transduction current in either cochlear or vestibular hair cells of HCN1- or HCN2- deficient mice relative to wild-type mice. Furthermore, mice that lacked both HCN1 and HCN2 also had normal transduction currents. Lastly, we found that mice exposed to the dominant-negative mutant form of HCN2 had normal transduction currents as well. Taken together, the evidence suggests that HCN subunits are not required for mechanotransduction in hair cells of the mouse inner ear.

  10. Effect of histone deacetylase inhibitors trichostatin A and valproic acid on hair cell regeneration in zebrafish lateral line neuromasts

    Directory of Open Access Journals (Sweden)

    Yingzi eHe

    2014-11-01

    Full Text Available In humans, auditory hair cells are not replaced when injured. Thus, cochlear hair cell loss causes progressive and permanent hearing loss. Conversely, nonmammalian vertebrates are capable of regenerating lost sensory hair cells. The zebrafish lateral line has numerous qualities that make it well suited for studying hair cell development and regeneration. Histone deacetylase (HDAC activity has been shown to have an important role in regenerative processes in vertebrates, but its function in hair cell regeneration in vivo is not fully understood. Here, we have examined the role of HDAC activity in hair cell regeneration in the zebrafish lateral line. We eliminated lateral line hair cells of 5-day post-fertilization larvae using neomycin and then treated the larvae with HDAC inhibitors. To assess hair cell regeneration, we used 5-bromo-2-deoxyuridine (BrdU incorporation in zebrafish larvae to label mitotic cells after hair cell loss. We found that pharmacological inhibition of HDACs using trichostatin A (TSA or valproic acid (VPA increased histone acetylation in the regenerated neuromasts following neomycin-induced damage. We also showed that treatment with TSA or VPA decreased the number of supporting cells and regenerated hair cells in response to hair cell damage. Additionally, BrdU immunostaining and western blot analysis showed that TSA or VPA treatment caused a significant decrease in the percentage of S-phase cells and induced p21Cip1 and p27Kip1 expression, both of which are likely to explain the decrease in the amount of newly regenerated hair cells in treated embryos. Finally, we showed that HDAC inhibitors induced no observable cell death in neuromasts as measured by cleaved caspase-3 immunohistochemistry and western blot analysis. Taken together, our results demonstrate that HDAC activity has an important role in the regeneration of hair cells in the lateral line.

  11. Cochlear Implant Using Neural Prosthetics

    Science.gov (United States)

    Gupta, Shweta; Singh, Shashi kumar; Dubey, Pratik Kumar

    2012-10-01

    This research is based on neural prosthetic device. The oldest and most widely used of these electrical, and often computerized, devices is the cochlear implant, which has provided hearing to thousands of congenitally deaf people in this country. Recently, the use of the cochlear implant is expanding to the elderly, who frequently suffer major hearing loss. More cutting edge are artificial retinas, which are helping dozens of blind people see, and ìsmartî artificial arms and legs that amputees can maneuver by thoughts alone, and that feel more like real limbs.Research, which curiosity led to explore frog legs dancing during thunderstorms, a snail shapedorgan in the inner ear, and how various eye cells react to light, have fostered an understanding of how to ìtalkî to the nervous system. That understanding combined with the miniaturization of electronics and enhanced computer processing has enabled prosthetic devices that often can bridge the gap in nerve signaling that is caused by disease or injury.

  12. Cochlear implantations in children with Waardenburg syndrome: an electrophysiological and psychophysical review.

    Science.gov (United States)

    Pau, Henry; Gibson, William P R; Gardner-Berry, Kirsty; Sanli, Halit

    2006-12-01

    Waardenburg syndrome presents with dystopia canthorum, pigmentary abnormalities of hair, iris and skin (often a white forelock and heterochromia iridis) and sensorineural deafness. The authors review the electrophysiological and psychophysical findings of implanted children with Waardenburg syndrome at the Sydney Cochlear Implant Centre. Twenty children with Waardenburg syndrome received cochlear implants between 1985 and 2001. Electrical auditory brainstem response (EABR) was performed in all of these patients intra-operatively as part of the routine investigations. Only 13 of these patients were assessed one year or more post-operatively by means of the Melbourne Categories (0-7). Four patients (20%) were found to have abnormal EABR recordings. The mode of Melbourne Categories in this group (n = 3) was 1 at one year post-operation. The other 16 patients were found to have normal EABR and the mode of Melbourne Categories in this group (n = 10) was 7. A poor outcome after cochlear implantation was associated with abnormal EABR recordings (a 'true' auditory neuropathy) and was found in a significant proportion of patients with Waardenburg syndrome.

  13. Migration of R28 Retinal Precursor Cells into Cochlear and Vestibular Organs

    Institute of Scientific and Technical Information of China (English)

    DING Dalian; Gail Seigel; Richard Salvi

    2006-01-01

    Damaged hair cells and neurons in the inner ear generally can not be replaced in mammals. The loss of these cells causes permanent functional disorders in both the cochlear and vestibular systems. Transplantation of retinal precursor cells, R28 cells, into inner ear tissue may help replace missing cells. The aim of the current project was to induce R28 cell transdifferentiation into cochlear and vestibular cell types under culture conditions. The first part was related to R28 cell labeling with DiI fluorescence that would help identify and track R28 cells. The second part involved co-culturing R28 cells in cochlear and vestibular organotropic cultures or isolated spiral ganglion neurons. The results suggest that R28 cells have the potential to differentiate into supporting cell types and spiral ganglion neurons in serum free medium, probably under the influence of diffusible signals from inner ear tissues. This information is useful for future efforts in inducing stem cell differentiation in the inner ear to replace lost sensory and neural cells.

  14. Deafness induced by Connexin 26 (GJB2) deficiency is not determined by endocochlear potential (EP) reduction but is associated with cochlear developmental disorders.

    Science.gov (United States)

    Chen, Jin; Chen, Jing; Zhu, Yan; Liang, Chun; Zhao, Hong-Bo

    2014-05-23

    Connexin 26 (Cx26, GJB2) mutations are the major cause of hereditary deafness and are responsible for >50% of nonsyndromic hearing loss. Mouse models show that Cx26 deficiency can cause congenital deafness with cochlear developmental disorders, hair cell degeneration, and the reduction of endocochlear potential (EP) and active cochlear amplification. However, the underlying deafness mechanism still remains undetermined. Our previous studies revealed that hair cell degeneration is not a primary cause of hearing loss. In this study we investigated the role of EP reduction in Cx26 deficiency-induced deafness. We found that the EP reduction is not associated with congenital deafness in Cx26 knockout (KO) mice. The threshold of auditory brainstem response (ABR) in Cx26 KO mice was even greater than 110 dB SPL, demonstrating complete hearing loss. However, the EP in Cx26 KO mice varied and not completely abolished. In some cases, the EP could still remain at higher levels (>70 mV). We further found that the deafness in Cx26 KO mice is associated with cochlear developmental disorders. Deletion of Cx26 in the cochlea before postnatal day 5 (P5) could cause congenital deafness. The cochlea had developmental disorders and the cochlear tunnel was not open. However, no congenital deafness was found when Cx26 was deleted after P5. The cochlea also displayed normal development and the cochlear tunnel was open normally. These data suggest that congenital deafness induced by Cx26 deficiency is not determined by EP reduction and may result from cochlear developmental disorders.

  15. Ejecting chick cheats: a changing paradigm?

    Directory of Open Access Journals (Sweden)

    Grim Tomáš

    2011-06-01

    Full Text Available Abstract Evolutionary arms-races between avian brood parasites and their hosts have typically resulted in some spectacular adaptations, namely remarkable host ability to recognize and reject alien eggs and, in turn, sophisticated parasite egg mimicry. In a striking contrast to hosts sometimes rejecting even highly mimetic eggs, the same species typically fail to discriminate against highly dissimilar parasite chicks. Understanding of this enigma is still hampered by the rarity of empirical tests - and consequently evidence - for chick discrimination. Recent work on Australian host-parasite systems (Gerygone hosts vs. Chalcites parasites, increased not only the diversity of hosts showing chick discrimination, but also discovered an entirely novel host behavioural adaptation. The hosts do not desert parasite chicks (as in all previously reported empirical work but physically remove living parasites from their nests. Here, I briefly discuss these exciting findings and put them in the context of recent empirical and theoretical work on parasite chick discrimination. Finally, I review factors responsible for a relatively slow progress in this research area and suggest most promising avenues for future research.

  16. The effect of quinine on outer hair cell shape, compliance and force.

    Science.gov (United States)

    Jarboe, J K; Hallworth, R

    1999-06-01

    Quinine intoxication causes a well-described syndrome that includes tinnitus, sensorineural hearing loss and vertigo. The pathophysiology of quinine's effects on hearing is unknown, but may include a peripheral component. The cochlear outer hair cell is known to be motile and to contribute force to amplify the vibration pattern of the organ of Corti. The outer hair cell is also a target of diseases involving tinnitus and sensorineural hearing loss, including salicylate intoxication. These effects may be mediated through changes either in motile force or in mechanical properties. Quinine's effects on outer hair cell motility and mechanical properties have therefore been examined in vitro. Quinine at 5.0 mM substantially decreased active force generation in isolated guinea pig cochlear outer hair cells. Isolated cells also elongated and dilated in diameter when exposed to 5.0 mM quinine. No consistent changes in mechanical properties were observed. 1.0 mM quinine was ineffective in either force reduction or elongation. Trifluoperazine, a calmodulin inhibitor, and ML-9, a blocker of myosin light chain kinases, were ineffective in blocking quinine-induced force reduction or elongation. Deferoxamine, a hydroxyl free radical scavenger, also failed to block either the force decrease or the elongation.

  17. Cochlear implant: what the radiologist should know

    Directory of Open Access Journals (Sweden)

    Natalia Delage Gomes

    2013-06-01

    Full Text Available Cochlear implant is the method of choice in the treatment of deep sensorineural hypoacusis, particularly in patients where conventional amplification devices do not imply noticeable clinical improvement. Imaging findings are crucial in the indication or contraindication for such surgical procedure. In the assessment of the temporal bone, radiologists should be familiar with relative or absolute contraindication factors, as well as with factors that might significantly complicate the implantation. Some criteria such as cochlear nerve aplasia, labyrinthine and/or cochlear aplasia are still considered as absolute contraindications, in spite of studies bringing such criteria into question. Cochlear dysplasias constitute relative contraindications, among them labyrinthitis ossificans is highlighted. Other alterations may be mentioned as complicating agents in the temporal bone assessment, namely, hypoplasia of the mastoid process, aberrant facial nerve, otomastoiditis, otosclerosis, dehiscent jugular bulb, enlarged endolymphatic duct and sac. The experienced radiologist assumes an important role in the evaluation of this condition.

  18. Cochlear implant in an ambulatory surgery center.

    Science.gov (United States)

    Joseph, Aimee M; Lassen, L Frederick

    2013-02-01

    Presbycusis, or sensorineural hearing loss in the elderly population, affects approximately 40% to 50% of people over the age of 75. A variety of devices are available to those with hearing loss. Cochlear implants, for example, are especially useful for those with severe-to-profound hearing loss. The population is aging, so the demand for cochlear implantation in ambulatory surgery centers will likely increase. Ambulatory surgery centers (ASC) can provide a more convenient and less expensive location for cochlear implant surgery than hospital-based operating facilities. Patient selection using standard ASC criteria, coupled with an understanding of the unique surgical and anesthetic needs of cochlear implant patients, are key to bringing this once exotic inpatient procedure into the ASC.

  19. Black Hair is Beautiful

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    On June 9, the 1994 ⅩⅢ Asian Make-up and Hairstyling Competition was held in Beijing. More than 200 contestants from 12 countries and regions across Asia participated. The competition is now considered the largest and most prestigious exchange activity in Asian beauty and hair circles. Black Hair is Beautiful" was the theme of this competition, which stressed Asian physical characteristics and aesthetics.

  20. Social inclusion of children with cochlear implants

    OpenAIRE

    Tomič, Katarina

    2016-01-01

    In the last few decades the progress of science has enabled the development of cochlear implant, which is suitable for persons who have defected inner ear, so hearing amplification is no longer enough for them. It allows them to perceive sound and develop verbal language, which provide better quality of life. Because of that, around the world and also in Slovenia, more and more children with cochlear implants are being placed in mainstream school settings. Recently, researchers are paying mor...

  1. Control temperature of young chicks to reduce mortality

    NARCIS (Netherlands)

    Lourens, A.; Kuijpers, M.

    2002-01-01

    Individual chicks may have different environmental temperature demands. The trick is to provide every chick with the right body temperature. By measuring individual chick temperatures, hatchery staff and broiler growers or layer producers are better able to provide the right environmental temperatur

  2. [Cochlear implantation through the middle fossa approach].

    Science.gov (United States)

    Szyfter, W; Colletti, V; Pruszewicz, A; Kopeć, T; Szymiec, E; Kawczyński, M; Karlik, M

    2001-01-01

    The inner part of cochlear implant is inserted into inner ear during surgery through mastoid and middle ear. It is a classical method, used in the majority cochlear centers in the world. This is not a suitable method in case of chronic otitis media and middle ear malformation. In these cases Colletti proposed the middle fossa approach and cochlear implant insertion omitting middle ear structures. In patient with bilateral chronic otitis media underwent a few ears operations without obtaining dry postoperative cavity. Cochlear implantation through the middle fossa approach was performed in this patient. The bone fenster was cut, temporal lobe was bent and petrosus pyramid upper surface was exposed. When the superficial petrosal greater nerve, facial nerve and arcuate eminence were localised, the cochlear was open in the basal turn and electrode were inserted. The patient achieves good results in the postoperative speech rehabilitation. It confirmed Colletti tesis that deeper electrode insertion in the cochlear implantation through the middle fossa approach enable use of low and middle frequencies, which are very important in speech understanding.

  3. Hydrogen peroxide potentiates organophosphate toxicosis in chicks

    Directory of Open Access Journals (Sweden)

    Banan K. Al-Baggou

    2011-11-01

    Full Text Available Objective: The purpose of the present study was to examine the effect of hydrogen peroxide(H2O2 on the acute toxicity of organophosphate insecticides dichlorvos and diazinon and their inhibitoryactions on plasma, brain and liver cholinesterase activities. Material and Methods: H2O2 was given indrinking water (0.5% v/v for 2 weeks in unsexed day old chicks, a regimen known to induce oxidativestress in this species. A control group received drinking tap water. All experiments were conducted onthe chicks at the age of 15 days after exposure to H2O2. The acute (24 h oral LD50 values of dichlorvosand diazinon in the insecticidal preparations as determined by the up-and-down method in the controlchicks were 9.4 and 15.6 mg/kg, respectively. Results: The poisoned chicks manifested signs ofcholinergic toxicosis within one hour after the dosing including salivation, lacrimation, gasping, frequentdefecation, drooping of wings, tremors, convulsions and recumbency. The acute (24 h oral LD50 valuesof dichlorvos and diazinon in chicks provided with H2O2 were reduced to 3.5 and 6.5 mg/kg, by 63 and58%, respectively when compared to respective control LD50 values. The intoxicated chicks also showedcholinergic signs of toxicosis as described above. Plasma, brain and liver cholinesterase activities of thechicks exposed to H2O2 were significantly lower than their respective control (H2O values by 25, 28 and27%, respectively. Oral dosing of chicks with dichlorvos at 3 mg/kg significantly inhibited cholinesteraseactivities in the plasma, brain and liver of both control (42-67% and H2O2-treated (15-59% chicks.Diazinon at 5 mg/kg, orally also inhibited cholinesterase activities in the plasma, brain and liver of bothcontrol (36-66% and H2O2-treated (15-30% chicks. In the H2O2 groups, dichlorvos inhibition of livercholinesterase activity and diazinon inhibition of liver and brain cholinesterase activities weresignificantly lesser than those of the respective values of

  4. Effects of salicylate on shape, electromotility and membrane characteristics of isolated outer hair cells from guinea pig cochlea.

    Science.gov (United States)

    Shehata, W E; Brownell, W E; Dieler, R

    1991-01-01

    A reversible tinnitus and hearing loss have long been known to result from large doses of salicylate. Cochlear electrophysiology and otoacoustic emission studies suggest that the drug may interfere with outer hair cell electromotility. Exposure of isolated outer hair cells to sodium salicylate concentrations ranging from 0.05 to 10 mM reveals a dose dependent, reversible loss of turgidity and dimunition of electromotility. There was also a change in membrane conductance with salicylate superfusion that occurred later in time from the onset of shape and electromotility changes. There was no evidence of dose dependence for the change in membrane conductance, nor was the change reversible. The changes in shape and electromotility that we observe in vitro may impair cochlear partition movements in vivo and could account, at least in part, for the salicylate-induced hearing loss and effects on otoacoustic emissions.

  5. Cochlear implantation in children with complex needs: The perceptions of professionals at cochlear implant centres

    NARCIS (Netherlands)

    Archbold, S.M.; Athalye, S.; Mulla, I.; Harrigan, S.; Wolters, N.; Isarin, J.; Knoors, H.E.T.

    2016-01-01

    Objective To explore the views of cochlear implant centre teams about the process of referral, assessment and rehabilitation for children with complex needs. Methods An on-line survey of cochlear implant centres in the UK and in the Netherlands was carried out, with both quantitative and qualitative

  6. The group delay and suppression pattern of the cochlear microphonic potential recorded at the round window.

    Directory of Open Access Journals (Sweden)

    Wenxuan He

    Full Text Available BACKGROUND: It is commonly assumed that the cochlear microphonic potential (CM recorded from the round window (RW is generated at the cochlear base. Based on this assumption, the low-frequency RW CM has been measured for evaluating the integrity of mechanoelectrical transduction of outer hair cells at the cochlear base and for studying sound propagation inside the cochlea. However, the group delay and the origin of the low-frequency RW CM have not been demonstrated experimentally. METHODOLOGY/PRINCIPAL FINDINGS: This study quantified the intra-cochlear group delay of the RW CM by measuring RW CM and vibrations at the stapes and basilar membrane in gerbils. At low sound levels, the RW CM showed a significant group delay and a nonlinear growth at frequencies below 2 kHz. However, at high sound levels or at frequencies above 2 kHz, the RW CM magnitude increased proportionally with sound pressure, and the CM phase in respect to the stapes showed no significant group delay. After the local application of tetrodotoxin the RW CM below 2 kHz became linear and showed a negligible group delay. In contrast to RW CM phase, the BM vibration measured at location ∼2.5 mm from the base showed high sensitivity, sharp tuning, and nonlinearity with a frequency-dependent group delay. At low or intermediate sound levels, low-frequency RW CMs were suppressed by an additional tone near the probe-tone frequency while, at high sound levels, they were partially suppressed only at high frequencies. CONCLUSIONS/SIGNIFICANCE: We conclude that the group delay of the RW CM provides no temporal information on the wave propagation inside the cochlea, and that significant group delay of low-frequency CMs results from the auditory nerve neurophonic potential. Suppression data demonstrate that the generation site of the low-frequency RW CM shifts from apex to base as the probe-tone level increases.

  7. Fibro-vascular coupling in the control of cochlear blood flow.

    Directory of Open Access Journals (Sweden)

    Min Dai

    Full Text Available BACKGROUND: Transduction of sound in the cochlea is metabolically demanding. The lateral wall and hair cells are critically vulnerable to hypoxia, especially at high sound levels, and tight control over cochlear blood flow (CBF is a physiological necessity. Yet despite the importance of CBF for hearing, consensus on what mechanisms are involved has not been obtained. METHODOLOGY/PRINCIPAL FINDINGS: We report on a local control mechanism for regulating inner ear blood flow involving fibrocyte signaling. Fibrocytes in the super-strial region are spatially distributed near pre-capillaries of the spiral ligament of the albino guinea pig cochlear lateral wall, as demonstrably shown in transmission electron microscope and confocal images. Immunohistochemical techniques reveal the inter-connected fibrocytes to be positive for Na+/K+ ATPase β1 and S100. The connected fibrocytes display more Ca(2+ signaling than other cells in the cochlear lateral wall as indicated by fluorescence of a Ca(2+ sensor, fluo-4. Elevation of Ca(2+ in fibrocytes, induced by photolytic uncaging of the divalent ion chelator o-nitrophenyl EGTA, results in propagation of a Ca(2+ signal to neighboring vascular cells and vasodilation in capillaries. Of more physiological significance, fibrocyte to vascular cell coupled signaling was found to mediate the sound stimulated increase in cochlear blood flow (CBF. Cyclooxygenase-1 (COX-1 was required for capillary dilation. CONCLUSIONS/SIGNIFICANCE: The findings provide the first evidence that signaling between fibrocytes and vascular cells modulates CBF and is a key mechanism for meeting the cellular metabolic demand of increased sound activity.

  8. Essential of Hair Care Cosmetics

    Directory of Open Access Journals (Sweden)

    Aurora Alessandrini

    2016-09-01

    Full Text Available Nowadays, hair care and style play a very important role in people’s physical aspect and self-perception. Hair cosmetics can be distinguished into two main categories: cosmetics with temporary effect on the hair, for example shampoos, conditioners, sprays, and temporary colors; and cosmetics with permanent effect on the hair, such as permanent waves, relaxers, bleaches and permanent colors. These cosmetic procedures may induce hair abnormalities. We provide an overview on the most important characteristics of these procedures, analyzing components and effects on the hair. Finally, we evaluated new camouflage techniques and tattoo scalp.

  9. Effect of pediatric bilateral cochlear implantation on language development

    NARCIS (Netherlands)

    Boons, Tinne; Brokx, Jan; Frijns, Johan; Peeraer, Louis; Philips, Birgit; Vermeulen,; Wouters,; Wieringen, van

    2012-01-01

    Objective: To examine spoken language outcomes in children undergoing bilateral cochlear implantation compared with matched peers undergoing unilateral implantation. Design: Case-control, frequency-matched, retrospective cross-sectional multicenter study. Setting: Two Belgian and 3 Dutch cochlear im

  10. Cochlear Implants Keep Twin Sisters Learning, Discovering Together

    Science.gov (United States)

    ... Past Issues Special Section: Focus on Communication Cochlear Implants Past Issues / Fall 2008 Table of Contents For ... right, and Isabelle Jeppsen meet with Mia's cochlear implant surgeon, John Niparko, M.D., of Johns Hopkins ...

  11. Risk of Bacterial Meningitis in Children with Cochlear Implants

    Science.gov (United States)

    ... Information For... Media Policy Makers Risk of Bacterial Meningitis in Children with Cochlear Implants Language: English Español ( ... Compartir 2002 Study of the Risk of Bacterial Meningitis in Children with Cochlear Implants Many people have ...

  12. Conventional and cross-correlation brain-stem auditory evoked responses in the white leghorn chick: rate manipulations

    Science.gov (United States)

    Burkard, R.; Jones, S.; Jones, T.

    1994-01-01

    Rate-dependent changes in the chick brain-stem auditory evoked response (BAER) using conventional averaging and a cross-correlation technique were investigated. Five 15- to 19-day-old white leghorn chicks were anesthetized with Chloropent. In each chick, the left ear was acoustically stimulated. Electrical pulses of 0.1-ms duration were shaped, attenuated, and passed through a current driver to an Etymotic ER-2 which was sealed in the ear canal. Electrical activity from stainless-steel electrodes was amplified, filtered (300-3000 Hz) and digitized at 20 kHz. Click levels included 70 and 90 dB peSPL. In each animal, conventional BAERs were obtained at rates ranging from 5 to 90 Hz. BAERs were also obtained using a cross-correlation technique involving pseudorandom pulse sequences called maximum length sequences (MLSs). The minimum time between pulses, called the minimum pulse interval (MPI), ranged from 0.5 to 6 ms. Two BAERs were obtained for each condition. Dependent variables included the latency and amplitude of the cochlear microphonic (CM), wave 2 and wave 3. BAERs were observed in all chicks, for all level by rate combinations for both conventional and MLS BAERs. There was no effect of click level or rate on the latency of the CM. The latency of waves 2 and 3 increased with decreasing click level and increasing rate. CM amplitude decreased with decreasing click level, but was not influenced by click rate for the 70 dB peSPL condition. For the 90 dB peSPL click, CM amplitude was uninfluenced by click rate for conventional averaging. For MLS BAERs, CM amplitude was similar to conventional averaging for longer MPIs.(ABSTRACT TRUNCATED AT 250 WORDS).

  13. Toxicity of metal mixtures to chick embryos

    Energy Technology Data Exchange (ETDEWEB)

    Birge, W.J.; Roberts, O.W.; Black, J.A.

    1976-09-01

    The toxic effects of mercury/selenium and certain other metal mixtures on the chick embryo are examined to determine whether antagonistic, additive or synergistic interactions occur. White Plymouth Rock chicken eggs were treated by yolk injection with cadmium chloride, mercuric chloride, zinc chloride and sodium selenate. Test aliquots were injected prior to incubation using the needle track procedure. Using a sample size of 200, percent survival was determined as hatchability of experimental eggs/controls. Metal mixtures used included mercury/cadmium, mercury/selenium, mercury/zinc, cadmium/selenium, and cadmium/zinc. Except for mercury/selenium, all other metal mixtures gave actual values that were within 5% of those for additive toxic effects. Actual hatchability frequencies for test concentrations of mercury/selenium indicated a moderate degree of synergism. Results indicate that the strong mercury/selenium synergism which affects embryonic development in the carp does not apply for the chick embryo; that most two-way combinations of cadmium, mercury, selenium and zinc exert purely additive effects on chick hatchability; and that these metal mixtures give no discernible antagonistic interactions which affect survival of chick embryos. (MFB)

  14. The biology of hair diversity.

    Science.gov (United States)

    Westgate, Gillian E; Botchkareva, Natalia V; Tobin, Desmond J

    2013-08-01

    Hair diversity, its style, colour, shape and growth pattern is one of our most defining characteristics. The natural versus temporary style is influenced by what happens to our hair during our lifetime, such as genetic hair loss, sudden hair shedding, greying and pathological hair loss in the various forms of alopecia because of genetics, illness or medication. Despite the size and global value of the hair care market, our knowledge of what controls the innate and within-lifetime characteristics of hair diversity remains poorly understood. In the last decade, drivers of knowledge have moved into the arena of genetics where hair traits are obvious and measurable and genetic polymorphisms are being found that raise valuable questions about the biology of hair growth. The recent discovery that the gene for trichohyalin contributes to hair shape comes as no surprise to the hair biologists who have believed for 100 years that hair shape is linked to the structure and function of the inner root sheath. Further conundrums awaiting elucidation include the polymorphisms in the androgen receptor (AR) described in male pattern alopecia whose location on the X chromosome places this genetic contributor into the female line. The genetics of female hair loss is less clear with polymorphisms in the AR not associated with female pattern hair loss. Lifestyle choices are also implicated in hair diversity. Greying, which also has a strong genetic component, is often suggested to have a lifestyle (stress) influence and hair follicle melanocytes show declining antioxidant protection with age and lowered resistance to stress. It is likely that hair research will undergo a renaissance on the back of the rising information from genetic studies as well as the latest contributions from the field of epigenetics.

  15. Society of Hair Testing guidelines for drug testing in hair.

    Science.gov (United States)

    Cooper, Gail A A; Kronstrand, Robert; Kintz, Pascal

    2012-05-10

    The Society of Hair Testing (SoHT) Guidelines for Drug Testing in Hair provide laboratories with recommended best practice guidelines whether they are currently offering drug testing in hair, or plan to offer a hair testing service in the future. The guidelines include reference to recommended sample collection and storage procedures, through sample preparation, pre-treatment and analysis and the use of cut-offs.

  16. Body hair transplant: An additional source of donor hair in hair restoration surgery

    Directory of Open Access Journals (Sweden)

    Poswal Arvind

    2007-01-01

    Full Text Available Androgenic alopecia (pattern baldness is a condition in which there is androgen mediated progressive miniaturization and loss of hair follicles in a genetically susceptible individual. A 47-year-old male patient with advanced degree of hair loss (Norwood 6 category wanted to go for full hair restoration surgery. Due to the limited availability of donor hair in the scalp, a small session with 700-chest hair was performed. On follow-up at eight months it was observed that chest hair grew and formed a cosmetically acceptable forelock.

  17. Hair cell bundles: flexoelectric motors of the inner ear.

    Directory of Open Access Journals (Sweden)

    Kathryn D Breneman

    Full Text Available Microvilli (stereocilia projecting from the apex of hair cells in the inner ear are actively motile structures that feed energy into the vibration of the inner ear and enhance sensitivity to sound. The biophysical mechanism underlying the hair bundle motor is unknown. In this study, we examined a membrane flexoelectric origin for active movements in stereocilia and conclude that it is likely to be an important contributor to mechanical power output by hair bundles. We formulated a realistic biophysical model of stereocilia incorporating stereocilia dimensions, the known flexoelectric coefficient of lipid membranes, mechanical compliance, and fluid drag. Electrical power enters the stereocilia through displacement sensitive ion channels and, due to the small diameter of stereocilia, is converted to useful mechanical power output by flexoelectricity. This motor augments molecular motors associated with the mechanosensitive apparatus itself that have been described previously. The model reveals stereocilia to be highly efficient and fast flexoelectric motors that capture the energy in the extracellular electro-chemical potential of the inner ear to generate mechanical power output. The power analysis provides an explanation for the correlation between stereocilia height and the tonotopic organization of hearing organs. Further, results suggest that flexoelectricity may be essential to the exquisite sensitivity and frequency selectivity of non-mammalian hearing organs at high auditory frequencies, and may contribute to the "cochlear amplifier" in mammals.

  18. Arginine requirement of starting broiler chicks.

    Science.gov (United States)

    Cuca, M; Jensen, L S

    1990-08-01

    Three experiments were conducted to estimate the arginine requirement of male broiler chicks from 0 to 3 wk of age. The experiments were conducted in battery brooders with wires floors, and the birds received water and feed ad libitum. In the first experiment, chicks were fed a diet based on corn, soybean meal, casein, and corn-gluten meal containing 3,200 kcal ME per kg and either 20 or 23% crude protein. Regression analysis indicated an arginine requirement of 1.22% for maximum growth rate and feed efficiency with the 20% protein diet. For chicks fed the 23% protein diet, neither growth rate nor feed efficiency was significantly different among the diets containing arginine ranging from 1.13 to 1.43%. In the second experiment, a basal diet was used containing 17.5% casein and 22.5% protein with arginine ranging from 1.03 to 1.43%. An arginine requirement of 1.18% for maximum body weight gain was estimated by regression analysis, but no significant response to arginine above the basal level was observed for feed efficiency. Performance of chicks fed the basal diet was somewhat reduced because of a difficulty with adherence of feed to the beaks. In a third experiment, three basal diets containing 21, 22, or 23% protein were formulated from practical ingredients without use of casein. The requirement for maximum growth rate and feed efficiency was estimated to be 1.24 to 1.28% for the three diets. The results of these investigations indicate that the arginine requirement for starting chicks suggested by the National Research Council in 1984 of 1.44% in diets containing 3,200 kcal ME per kg is too high for practical diets. The data presented here support an arginine requirement of 1.25%.

  19. Laser assisted hair-removal.

    Science.gov (United States)

    Choudhary, S; Elsaie, M L; Nouri, K

    2009-10-01

    A number of lasers and light devices are now available for the treatment of unwanted hair. The goal of laser hair removal is to damage stem cells in the bulge of the hair follicle by targeting melanin, the endogenous chromophore for laser and light devices utilized to remove hair. The competing chromophores in the skin and hair, oxyhemoglobin and water, have a decreased absorption between 690 nm and 1000 nm, thus making this an ideal range for laser and light sources. Laser hair removal is achieved through follicular unit destruction based on selective photothermolysis. The principle of selective photothermolysis predicts that the thermal injury will be restricted to a given target if there is sufficient selective absorption of light and the pulse duration is shorter than the thermal relaxation time of the target. This review will focus on the mechanisms of laser assisted hair removal and provide an update on the newer technologies emerging in the field of lasers assisted hair removal.

  20. Factors associated with hearing loss in a normal-hearing guinea pig model of Hybrid cochlear implants.

    Science.gov (United States)

    Tanaka, Chiemi; Nguyen-Huynh, Anh; Loera, Katherine; Stark, Gemaine; Reiss, Lina

    2014-10-01

    The Hybrid cochlear implant (CI), also known as Electro-Acoustic Stimulation (EAS), is a new type of CI that preserves residual acoustic hearing and enables combined cochlear implant and hearing aid use in the same ear. However, 30-55% of patients experience acoustic hearing loss within days to months after activation, suggesting that both surgical trauma and electrical stimulation may cause hearing loss. The goals of this study were to: 1) determine the contributions of both implantation surgery and EAS to hearing loss in a normal-hearing guinea pig model; 2) determine which cochlear structural changes are associated with hearing loss after surgery and EAS. Two groups of animals were implanted (n = 6 per group), with one group receiving chronic acoustic and electric stimulation for 10 weeks, and the other group receiving no direct acoustic or electric stimulation during this time frame. A third group (n = 6) was not implanted, but received chronic acoustic stimulation. Auditory brainstem response thresholds were followed over time at 1, 2, 6, and 16 kHz. At the end of the study, the following cochlear measures were quantified: hair cells, spiral ganglion neuron density, fibrous tissue density, and stria vascularis blood vessel density; the presence or absence of ossification around the electrode entry was also noted. After surgery, implanted animals experienced a range of 0-55 dB of threshold shifts in the vicinity of the electrode at 6 and 16 kHz. The degree of hearing loss was significantly correlated with reduced stria vascularis vessel density and with the presence of ossification, but not with hair cell counts, spiral ganglion neuron density, or fibrosis area. After 10 weeks of stimulation, 67% of implanted, stimulated animals had more than 10 dB of additional threshold shift at 1 kHz, compared to 17% of implanted, non-stimulated animals and 0% of non-implanted animals. This 1-kHz hearing loss was not associated with changes in any of the cochlear measures

  1. Mercury analysis in hair

    DEFF Research Database (Denmark)

    Esteban, Marta; Schindler, Birgit K; Jiménez-Guerrero, José A

    2015-01-01

    Human biomonitoring (HBM) is an effective tool for assessing actual exposure to chemicals that takes into account all routes of intake. Although hair analysis is considered to be an optimal biomarker for assessing mercury exposure, the lack of harmonization as regards sampling and analytical...... assurance program (QAP) for assessing mercury levels in hair samples from more than 1800 mother-child pairs recruited in 17 European countries. To ensure the comparability of the results, standard operating procedures (SOPs) for sampling and for mercury analysis were drafted and distributed to participating...... laboratories. Training sessions were organized for field workers and four external quality-assessment exercises (ICI/EQUAS), followed by the corresponding web conferences, were organized between March 2011 and February 2012. ICI/EQUAS used native hair samples at two mercury concentration ranges (0...

  2. Hair follicle proteoglycans

    DEFF Research Database (Denmark)

    Couchman, J R

    1993-01-01

    that are present in the epithelial and stromal compartments of hair follicles. However, the transmembrane proteoglycan syndecan may be important in follicle morphogenesis, both with respect to the epithelium and dermal papilla cells. Syndecan may possess both heparan and chondroitin sulfate chains, interacts...... basement membranes, including those surrounding the epithelial compartment of hair follicles. Additionally, and quite unlike the dermis, the dermal papilla is enriched in basement-membrane components, especially a chondroitin 6-sulfate-containing proteoglycan, BM-CSPG. The function of this proteoglycan...... is not known, but developmental studies indicate that it may have a role in stabilizing basement membranes. In the hair cycle, BM-CSPG decreases through catagen and is virtually absent from the telogen papilla. One or more heparan sulfate proteoglycans, including perlecan, are also present in papilla...

  3. Efficient estimates of cochlear hearing loss parameters in individual listeners

    DEFF Research Database (Denmark)

    Fereczkowski, Michal; Jepsen, Morten Løve; Dau, Torsten

    2013-01-01

    It has been suggested that the level corresponding to the knee-point of the basilar membrane (BM) input/output (I/O) function can be used to estimate the amount of inner- and outer hair-cell loss (IHL, OHL) in listeners with a moderate cochlear hearing impairment Plack et al. (2004). According...... to Jepsen and Dau (2011) IHL + OHL = HLT [dB], where HLT stands for total hearing loss. Hence having estimates of the total hearing loss and OHC loss, one can estimate the IHL. In the present study, results from forward masking experiments based on temporal masking curves (TMC; Nelson et al., 2001...... estimates of the knee-point level. Further, it is explored whether it is possible to estimate the compression ratio using only on-frequency TMCs. 10 normal-hearing and 10 hearing-impaired listeners (with mild-to-moderate sensorineural hearing loss) were tested at 1, 2 and 4 kHz. The results showed...

  4. Commissural axons of the mouse cochlear nucleus.

    Science.gov (United States)

    Brown, M Christian; Drottar, Marie; Benson, Thane E; Darrow, Keith

    2013-05-01

    The axons of commissural neurons that project from one cochlear nucleus to the other were studied after labeling with anterograde tracer. Injections were made into the dorsal subdivision of the cochlear nucleus in order to restrict labeling only to the group of commissural neurons that gave off collaterals to, or were located in, this subdivision. The number of labeled commissural axons in each injection was correlated with the number of labeled radiate multipolar neurons, suggesting radiate neurons as the predominant origin of the axons. The radiate commissural axons are thick and myelinated, and they exit the dorsal acoustic stria of the injected cochlear nucleus to cross the brainstem in the dorsal half, near the crossing position of the olivocochlear bundle. They enter the opposite cochlear nucleus via the dorsal and ventral acoustic stria and at its medial border. Reconstructions of single axons demonstrate that terminations are mostly in the core and typically within a single subdivision of the cochlear nucleus. Extents of termination range from narrow to broad along both the dorsoventral (i.e., tonotopic) and the rostrocaudal dimensions. In the electron microscope, labeled swellings form synapses that are symmetric (in that there is little postsynaptic density), a characteristic of inhibitory synapses. Our labeled axons do not appear to include excitatory commissural axons that end in edge regions of the nucleus. Radiate commissural axons could mediate the broadband inhibition observed in responses to contralateral sound, and they may balance input from the two ears with a quick time course.

  5. Segmented heterochromia in scalp hair.

    Science.gov (United States)

    Yoon, Kyeong Han; Kim, Daehwan; Sohn, Seonghyang; Lee, Won Soo

    2003-12-01

    Segmented heterochromia of scalp hair is characterized by the irregularly alternating segmentation of hair into dark and light bands and is known to be associated with iron deficiency anemia. The authors report the case of an 11-year-old boy with segmented heterochromia associated with iron deficiency anemia. After 11 months of iron replacement, the boy's segmented heterochromic hair recovered completely.

  6. Why Does Hair Turn Gray?

    Science.gov (United States)

    ... can get gray hair at any age. Some people go gray at a young age — as early as when they are in ... around the same age that our parents or grandparents first did. Gray hair is more noticeable in people with darker hair because it stands out, but ...

  7. Cochlear implantation in older adults.

    Science.gov (United States)

    Lin, Frank R; Chien, Wade W; Li, Lingsheng; Clarrett, Danisa M; Niparko, John K; Francis, Howard W

    2012-09-01

    Cochlear implants allow individuals with severe to profound hearing loss access to sound and spoken language. The number of older adults in the United States who are potential candidates for cochlear implantation (CI) is approximately 150,000 and will continue to increase with the aging of the population. Should CI be routinely recommended for these older adults, and do these individuals benefit from CI? We reviewed our 12-year experience with CI in adults aged ≥60 years (n = 445) at Johns Hopkins Medical Institutions to investigate the impact of CI on speech understanding and to identify factors associated with speech performance. Complete data on speech outcomes at baseline and 1 year post-CI were available for 83 individuals. Our results demonstrate that CI in adults aged ≥60 years consistently improved speech understanding scores, with a mean increase of 60.0% (SD 24.1) on HINT (Hearing in Noise Test) sentences in quiet. The magnitude of the gain in speech scores was negatively associated with age at implantation, such that for every increasing year of age at CI the gain in speech scores was 1.3 percentage points less (95% confidence interval [95% CI], 0.6-1.9) after adjusting for age at hearing loss onset. Conversely, individuals with higher pre-CI speech scores (HINT scores between 40% and 60%) had significantly greater post-CI speech scores by a mean of 10.0 percentage points (95% CI, 0.4-19.6) than those with lower pre-CI speech scores (HINT speech scores obtain the highest speech understanding scores after CI, with possible implications for current United States Medicare policy. Finally, we provide an extended discussion of the epidemiology and impact of hearing loss in older adults. Future research of CI in older adults should expand beyond simple speech outcomes to take into account the broad cognitive, social, and physical functioning outcomes that are likely detrimentally affected by hearing loss and may be mitigated by CI.

  8. Thinning Hair and Hair Loss: Could it be Female Pattern Hair Loss?

    Science.gov (United States)

    ... effective treatment for FPHL. Supplements: Many supplements, including biotin and folic acid, are said to help grow ... that the supplement helps regrow hair. Hair loss shampoos: These shampoos tend to do one of the ...

  9. Drug-induced hair loss.

    Science.gov (United States)

    2016-05-01

    Hair loss can have major psychological consequences. It can be due to a wide variety of causes, including hormonal disorders, dietary factors, infections, inflammation, trauma, emotional factors, and cancer. Drugs can also induce hair loss, by interacting with the hair growth cycle. Drug-induced hair loss may be immediate or delayed, sudden or gradual, and diffuse or localised. It is usually reversible after drug discontinuation. The drugs most often implicated in hair loss are anticancer agents, interferon, azole antifungals, lithium, immunosuppressants, and many other drugs belonging to a variety of pharmacological classes.

  10. Glutamate transporters EAAT4 and EAAT5 are expressed in vestibular hair cells and calyx endings.

    Directory of Open Access Journals (Sweden)

    Antoine Dalet

    Full Text Available Glutamate is the neurotransmitter released from hair cells. Its clearance from the synaptic cleft can shape neurotransmission and prevent excitotoxicity. This may be particularly important in the inner ear and in other sensory organs where there is a continually high rate of neurotransmitter release. In the case of most cochlear and type II vestibular hair cells, clearance involves the diffusion of glutamate to supporting cells, where it is taken up by EAAT1 (GLAST, a glutamate transporter. A similar mechanism cannot work in vestibular type I hair cells as the presence of calyx endings separates supporting cells from hair-cell synapses. Because of this arrangement, it has been conjectured that a glutamate transporter must be present in the type I hair cell, the calyx ending, or both. Using whole-cell patch-clamp recordings, we demonstrate that a glutamate-activated anion current, attributable to a high-affinity glutamate transporter and blocked by DL-TBOA, is expressed in type I, but not in type II hair cells. Molecular investigations reveal that EAAT4 and EAAT5, two glutamate transporters that could underlie the anion current, are expressed in both type I and type II hair cells and in calyx endings. EAAT4 has been thought to be expressed almost exclusively in the cerebellum and EAAT5 in the retina. Our results show that these two transporters have a wider distribution in mice. This is the first demonstration of the presence of transporters in hair cells and provides one of the few examples of EAATs in presynaptic elements.

  11. Manganese is toxic to spiral ganglion neurons and hair cells in vitro.

    Science.gov (United States)

    Ding, Dalian; Roth, Jerome; Salvi, Richard

    2011-03-01

    Occupational exposure to high atmospheric levels of Mn produces a severe and debilitating disorder known as manganism characterized by extrapyramidal disturbances similar to that seen in Parkinson's disease. Epidemiological and case studies suggest that persistent exposures to Mn may have deleterious effects on other organs including the auditory system and hearing. Mn accumulates in the inner ear following acute exposure raising the possibility that it can damage the sensory hair cells that convert sound into neural activity or spiral ganglion neurons (SGN) that transmit acoustic information from the hair cells to the brain via the auditory nerve. In this paper we demonstrate for first time that Mn causes significant damage to the sensory hair cells, peripheral auditory nerve fibers (ANF) and SGN in cochlear organotypic cultures isolated from postnatal day three rats. The peripheral ANF that make synaptic contact with the sensory hair cells were particularly vulnerable to Mn toxicity; damage occurred at concentrations as low 0.01 mM and increased with dose and duration of Mn exposure. Sensory hair cells, in contrast, were slightly more resistant to Mn toxicity than the ANF. Mn induced an atypical pattern of sensory cell damage; Mn was more toxic to inner hair cells (IHC) than outer hair cells (OHC) and in addition, IHC loss was relatively uniform along the length of the cochlea. Mn also caused significant loss and shrinkage of SGN soma. These findings are the first to demonstrate that Mn can produce severe lesions to both neurons and hair cells in the postnatal inner ear.

  12. Glutamate Transporters EAAT4 and EAAT5 Are Expressed in Vestibular Hair Cells and Calyx Endings

    Science.gov (United States)

    Gaboyard-Niay, Sophie; Calin-Jageman, Irina; Chidavaenzi, Robstein L.; Venteo, Stephanie; Desmadryl, Gilles; Goldberg, Jay M.; Lysakowski, Anna; Chabbert, Christian

    2012-01-01

    Glutamate is the neurotransmitter released from hair cells. Its clearance from the synaptic cleft can shape neurotransmission and prevent excitotoxicity. This may be particularly important in the inner ear and in other sensory organs where there is a continually high rate of neurotransmitter release. In the case of most cochlear and type II vestibular hair cells, clearance involves the diffusion of glutamate to supporting cells, where it is taken up by EAAT1 (GLAST), a glutamate transporter. A similar mechanism cannot work in vestibular type I hair cells as the presence of calyx endings separates supporting cells from hair-cell synapses. Because of this arrangement, it has been conjectured that a glutamate transporter must be present in the type I hair cell, the calyx ending, or both. Using whole-cell patch-clamp recordings, we demonstrate that a glutamate-activated anion current, attributable to a high-affinity glutamate transporter and blocked by DL-TBOA, is expressed in type I, but not in type II hair cells. Molecular investigations reveal that EAAT4 and EAAT5, two glutamate transporters that could underlie the anion current, are expressed in both type I and type II hair cells and in calyx endings. EAAT4 has been thought to be expressed almost exclusively in the cerebellum and EAAT5 in the retina. Our results show that these two transporters have a wider distribution in mice. This is the first demonstration of the presence of transporters in hair cells and provides one of the few examples of EAATs in presynaptic elements. PMID:23049999

  13. Musical experience sharpens human cochlear tuning.

    Science.gov (United States)

    Bidelman, Gavin M; Nelms, Caitlin; Bhagat, Shaum P

    2016-05-01

    The mammalian cochlea functions as a filter bank that performs a spectral, Fourier-like decomposition on the acoustic signal. While tuning can be compromised (e.g., broadened with hearing impairment), whether or not human cochlear frequency resolution can be sharpened through experiential factors (e.g., training or learning) has not yet been established. Previous studies have demonstrated sharper psychophysical tuning curves in trained musicians compared to nonmusicians, implying superior peripheral tuning. However, these findings are based on perceptual masking paradigms, and reflect engagement of the entire auditory system rather than cochlear tuning, per se. Here, by directly mapping physiological tuning curves from stimulus frequency otoacoustic emissions (SFOAEs)-cochlear emitted sounds-we show that estimates of human cochlear tuning in a high-frequency cochlear region (4 kHz) is further sharpened (by a factor of 1.5×) in musicians and improves with the number of years of their auditory training. These findings were corroborated by measurements of psychophysical tuning curves (PTCs) derived via simultaneous masking, which similarly showed sharper tuning in musicians. Comparisons between SFOAE and PTCs revealed closer correspondence between physiological and behavioral curves in musicians, indicating that tuning is also more consistent between different levels of auditory processing in trained ears. Our findings demonstrate an experience-dependent enhancement in the resolving power of the cochlear sensory epithelium and the spectral resolution of human hearing and provide a peripheral account for the auditory perceptual benefits observed in musicians. Both local and feedback (e.g., medial olivocochlear efferent) mechanisms are discussed as potential mechanisms for experience-dependent tuning.

  14. Energy output from a single outer hair cell

    CERN Document Server

    Iwasa, Kuni H

    2016-01-01

    Electromotility of outer hair cells (OHCs) has been extensively studied with in vitro experiments because of its physiological significance in the cochlear amplifier, which provides the exquisite sensitivity and frequency selectivity of the mammalian ear. However, these studies have been performed largely under load-free conditions or with static load, while these cells function in vivo in a dynamic environment, receiving electrical energy to enhance mechanical oscillation in the inner ear. This gap leaves uncertainties in addressing a key issue, how much mechanical energy an OHC provides. The present report is an attempt of bridging the gap by introducing a simple one-dimensional model for electromotility of OHC in a dynamic environment. This model incorporates a feedback loop involving the receptor potential and the mechanical load on OHC, and leads to an analytical expression for the membrane capacitance, which explicitly describes the dependence on the elastic load, viscous drag, and the mass. The derived...

  15. Restudy of malformations of the internal auditory meatus, cochlear nerve canal and cochlear nerve

    OpenAIRE

    Li, Youjin; YANG, Jun; Liu, Jinfen; Wu, Hao

    2014-01-01

    The present study aims to restudy the correlation between the internal auditory meatus (IAM), the cochlear nerve canal (CNC), the cochlear nerve (CN) and inner ear malformations. In this retrospective study design, the abnormal diameter of the IAM, CNC and CN in patients with any kind of inner ear malformations was evaluated using multi-slice spiral computed tomography (MSCT) (37 patients) and magnetic resonance imaging (MRI) (18 patients). Of 37 MSCT-diagnosed patients, 2 had IAM atresia, 11...

  16. Class III myosins shape the auditory hair bundles by limiting microvilli and stereocilia growth

    Science.gov (United States)

    Lelli, Andrea; Michel, Vincent; Boutet de Monvel, Jacques; Cortese, Matteo; Bosch-Grau, Montserrat; Aghaie, Asadollah; Perfettini, Isabelle; Dupont, Typhaine; Avan, Paul

    2016-01-01

    The precise architecture of hair bundles, the arrays of mechanosensitive microvilli-like stereocilia crowning the auditory hair cells, is essential to hearing. Myosin IIIa, defective in the late-onset deafness form DFNB30, has been proposed to transport espin-1 to the tips of stereocilia, thereby promoting their elongation. We show that Myo3a−/−Myo3b−/− mice lacking myosin IIIa and myosin IIIb are profoundly deaf, whereas Myo3a-cKO Myo3b−/− mice lacking myosin IIIb and losing myosin IIIa postnatally have normal hearing. Myo3a−/−Myo3b−/− cochlear hair bundles display robust mechanoelectrical transduction currents with normal kinetics but show severe embryonic abnormalities whose features rapidly change. These include abnormally tall and numerous microvilli or stereocilia, ungraded stereocilia bundles, and bundle rounding and closure. Surprisingly, espin-1 is properly targeted to Myo3a−/−Myo3b−/− stereocilia tips. Our results uncover the critical role that class III myosins play redundantly in hair-bundle morphogenesis; they unexpectedly limit the elongation of stereocilia and of subsequently regressing microvilli, thus contributing to the early hair bundle shaping. PMID:26754646

  17. Detection without deflection? A hypothesis for direct sensing of sound pressure by hair cells

    Indian Academy of Sciences (India)

    Andrew Bell

    2007-03-01

    It is widely thought that organisms detect sound by sensing the deflection of hair-like projections, the stereocilia, at the apex of hair cells. In the case of mammals, the standard interpretation is that hair cells in the cochlea respond to deflection of stereocilia induced by motion generated by a hydrodynamic travelling wave. But in the light of persistent anomalies, an alternative hypothesis seems to have some merit: that sensing cells (in particular the outer hair cells) may, at least at low intensities, be reacting to a different stimulus – the rapid pressure wave that sweeps through the cochlear fluids at the speed of sound in water. This would explain why fast responses are sometimes seen before the peak of the travelling wave. Yet how could cells directly sense fluid pressure? Here, a model is constructed of the outer hair cell as a pressure vessel able to sense pressure variations across its cuticular pore, and this ‘fontanelle’ model, based on the sensing action of the basal body at this compliant spot, could explain the observed anomalies. Moreover, the fontanelle model can be applied to a wide range of other organisms, suggesting that direct pressure detection is a general mode of sensing complementary to stereociliar displacement.

  18. Class III myosins shape the auditory hair bundles by limiting microvilli and stereocilia growth.

    Science.gov (United States)

    Lelli, Andrea; Michel, Vincent; Boutet de Monvel, Jacques; Cortese, Matteo; Bosch-Grau, Montserrat; Aghaie, Asadollah; Perfettini, Isabelle; Dupont, Typhaine; Avan, Paul; El-Amraoui, Aziz; Petit, Christine

    2016-01-18

    The precise architecture of hair bundles, the arrays of mechanosensitive microvilli-like stereocilia crowning the auditory hair cells, is essential to hearing. Myosin IIIa, defective in the late-onset deafness form DFNB30, has been proposed to transport espin-1 to the tips of stereocilia, thereby promoting their elongation. We show that Myo3a(-/-)Myo3b(-/-) mice lacking myosin IIIa and myosin IIIb are profoundly deaf, whereas Myo3a-cKO Myo3b(-/-) mice lacking myosin IIIb and losing myosin IIIa postnatally have normal hearing. Myo3a(-/-)Myo3b(-/-) cochlear hair bundles display robust mechanoelectrical transduction currents with normal kinetics but show severe embryonic abnormalities whose features rapidly change. These include abnormally tall and numerous microvilli or stereocilia, ungraded stereocilia bundles, and bundle rounding and closure. Surprisingly, espin-1 is properly targeted to Myo3a(-/-)Myo3b(-/-) stereocilia tips. Our results uncover the critical role that class III myosins play redundantly in hair-bundle morphogenesis; they unexpectedly limit the elongation of stereocilia and of subsequently regressing microvilli, thus contributing to the early hair bundle shaping.

  19. Quantifying hair shape and hair damage induced during reshaping of hair.

    Science.gov (United States)

    McMullen, Roger L; Zhang, Guojin; Gillece, Timothy

    2015-01-01

    The manipulation of hair shape, either to straighten or curl hair, is carried out on a grand scale in the hair care consumer market. Often, such changes are brought about through chemical or physical treatment, resulting in changes to hair chemistry. In this article, we review existing and present new data on methods to assess the efficacy of such treatments, mostly concentrating on imaging technologies used in conjunction with image analysis. In addition, we introduce spectroscopic imaging techniques and fluorescence spectrophotometry as tools to assess the biochemical state of the hair fiber as a result of hair shape modification regimens. Finally, we demonstrate how the structural integrity of the fiber is monitored with dynamic scanning calorimetry and traditional mechanical testing of the tensile properties of hair.

  20. West nile virus in American white pelican chicks: transmission, immunity, and survival

    Science.gov (United States)

    Sovada, Marsha A.; Pietz, Pamela J.; Hofmeister, Erik K.; Bartos, Alisa J.

    2013-01-01

    West Nile virus (WNV) causes significant mortality of American White Pelican chicks at northern plains colonies. We tested oropharyngeal/cloacal swabs from moribund chicks for shed WNV. Such shedding could enable chick-to-chick transmission and help explain why WNV spreads rapidly in colonies. WNV was detected on swabs from 11% of chicks in 2006 and 52% of chicks in 2007; however, viral titers were low. Before onset of WNV mortality, we tested blood from maternal antibodies. Among near-fledged chicks, 41% tested positive for anti-WNV antibodies, indicating that they survived infection. Among years and colonies, cumulative incidence of WNV in chicks varied from 28% to 81%, whereas the proportion of chicks surviving WNV (i.e., seropositive) was 64–75%. Our data revealed that WNV kills chicks that likely would fledge in the absence of WNV, that infection of chicks is pervasive, and that significant numbers of chicks survive infection.

  1. [Laser hair removal for urethral hair after hypospadias repair].

    Science.gov (United States)

    Kaneko, Tomoyuki; Nishimatsu, Hiroaki; Ogushi, Tetsuo; Sugimoto, Masayuki; Asakage, Yasuyuki; Kitamura, Tadaichi

    2008-01-01

    A 56-year-old male was admitted for induration of ventral side of the penile shaft. Computed tomography showed a large urethral calculus in the distal urethra. About 50 years previously, he had undergone multi-staged urethroplasty for hypospadias. He had also suffered from recurrent urethral calculi managed by urethrolithotomy 5 and 2 years before the admission. Urethrolithotomy revealed hair-bearing urethral calculus. Instillation of depilating agent containing thioglycolate into the neourethra for preventing hair regrowth was ineffective. Transurethral laser hair removal of neourethra was subsequently performed. All the neourethral follicles were ablated with GaAlAs diode laser (wave length 810 nm; at a power of 15W for 2 seconds) through a side-firing laser fiber. Another three operations were performed for a few regrown hairs at a power of 20-30W. Convalescence was uneventful. The patient is free of hair regrowth except for a hair at five months of follow-up.

  2. Active Hair-Bundle Motility by the Vertebrate Hair Cell

    Science.gov (United States)

    Tinevez, J.-Y.; Martin, P.; Jülicher, F.

    2009-02-01

    The hair bundle is both a mechano-sensory antenna and a force generator that might help the vertebrate hair cell from the inner ear to amplify its responsiveness to small stimuli. To study active hair-bundle motility, we combined calcium iontophoresis with mechanical stimulation of single hair bundles from the bullfrog's sacculus. A hair bundle could oscillate spontaneously, or be quiescent but display non-monotonic movements in response to abrupt force steps. Extracellular calcium changes or static biases to the bundle's position at rest could affect the kinetics of bundle motion and evoke transitions between the different classes of motility. The calcium-dependent location of a bundle's operating point within its nonlinear force-displacement relation controlled the type of movements observed. A unified theoretical description, in which mechanical activity stems from myosin-based adaptation and electro-mechanical feedback by Ca2+, could account for the fast and slow manifestations of active hair-bundle motility.

  3. Pattern of hair cell loss and delayed peripheral neuron degeneration in inner ear by a high-dose intratympanic gentamicin

    Institute of Scientific and Technical Information of China (English)

    Jintao Yu; Dalian Ding; Fengjun Wang; Haiyan Jiang; Hong Sun; Richard Salvi

    2014-01-01

    To gain insights into the ototoxic effects of aminoglycoside antibiotics (AmAn) and delayed peripheral ganglion neuron death in the inner ear, experimental animal models were widely used with several different approaches including AmAn systemic injections, combination treat-ment of AmAn and diuretics, or local application of AmAn. In these approaches, systemic AmAn treatment alone usually causes incomplete damage to hair cells in the inner ear. Co-administration of diuretic and AmAn can completely destroy the cochlear hair cells, but it is impossible to damage the vestibular system. Only the approach of AmAn local application can selectively eliminate most sensory hair cells in the inner ear. Therefore, AmAn local application is more suitable for studies for complete hair cell destructions in cochlear and vestibular system and the following delayed peripheral ganglion neuron death. In current studies, guinea pigs were unilaterally treated with a high concentration of gentamicin (GM, 40 mg/ml) through the tympanic membrane into the middle ear cavity. Auditory functions and vestibular functions were measured before and after GM treatment. The loss of hair cells and delayed degeneration of ganglion neurons in both cochlear and vestibular system were quantified 30 days or 60 days after treatment. The results showed that both auditory and vestibular functions were completely abolished after GM treatment. The sensory hair cells were totally missing in the cochlea, and severely destroyed in vestibular end-organs. The delayed spiral ganglion neuron death 60 days after the deafening procedure was over 50%. However, no obvious pathological changes were observed in vestibular ganglion neurons 60 days post-treatment. These results indicated that a high concentration of gentamycin delivered to the middle ear cavity can destroy most sensory hair cells in the inner ear that subsequently causes the delayed spiral ganglion neuron degeneration. This model might be useful for studies

  4. Peer Relationships of Children with Cochlear Implants.

    Science.gov (United States)

    Bat-Chava, Yael; Deignan, Elizabeth

    2001-01-01

    Qualitative and quantitative analysis of interviews with parents of children with cochlear implants found that, although implants have the potential to improve deaf children's relationships with hearing peers, these children still face communication obstacles which impede their social relationships. Results are discussed from the viewpoints of…

  5. Cochlear implants: our experience and literature review

    Directory of Open Access Journals (Sweden)

    Martins, Mariane Barreto Brandão

    2012-01-01

    Full Text Available Introduction: Cochlear Implants are important for individuals with severe to profound bilateral sensorineural hearing loss. Objective: Evaluate the experience of cochlear implant center of Otorhinolaryngology through the analysis of records of 9 patients who underwent cochlear implant surgery. Methods: This is a retrospective study performed with the patients records. Number 0191.0.107.000-11 ethics committee approval. We evaluated gender, etiology, age at surgery, duration of deafness, classification of deafness, unilateral or bilateral surgery, intraoperative and postoperative neural response and impedance of the electrodes in intraoperative and preoperative tests and found those that counter-indicated surgery. Results: There were 6 pediatric and 3 adult patients. Four male and 5 female. Etiologies: maternal rubella, cytomegalovirus, ototoxicity, meningitis, and sudden deafness. The age at surgery and duration of deafness ranged from 2 - 46 years and 2 - 18 years, respectively. Seven patients were pre-lingual. All had profound bilateral PA. There were 7 bilateral implants. Intraoperative complications: hemorrhage. Complications after surgery: vertigo and internal device failure. In 7 patients the electrodes were implanted through. Telemetry showed satisfactory neural response and impedance. CT and MRI was performed in all patients. We found enlargement of the vestibular aqueduct in a patient and incudomalleolar malformation. Conclusion: The cochlear implant as a form of auditory rehabilitation is well established and spreading to different centers specialized in otoaudiology. Thus, the need for structured services and trained professionals in this type of procedure is clear.

  6. Cochlear implants: our experience and literature review

    Science.gov (United States)

    Martins, Mariane Barreto Brandão; de Lima, Francis Vinicius Fontes; Santos, Ronaldo Carvalho; Santos, Arlete Cristina Granizo; Barreto, Valéria Maria Prado; de Jesus, Eduardo Passos Fiel

    2012-01-01

    Summary Introduction: Cochlear Implants are important for individuals with severe to profound bilateral sensorineural hearing loss. Objective: Evaluate the experience of cochlear implant center of Otorhinolaryngology through the analysis of records of 9 patients who underwent cochlear implant surgery. Methods: This is a retrospective study performed with the patients records. Number 0191.0.107.000-11 ethics committee approval. We evaluated gender, etiology, age at surgery, duration of deafness, classification of deafness, unilateral or bilateral surgery, intraoperative and postoperative neural response and impedance of the electrodes in intraoperative and preoperative tests and found those that counter-indicated surgery. Results: There were 6 pediatric and 3 adult patients. Four male and 5 female. Etiologies: maternal rubella, cytomegalovirus, ototoxicity, meningitis, and sudden deafness. The age at surgery and duration of deafness ranged from 2–46 years and 2–18 years, respectively. Seven patients were pre-lingual. All had profound bilateral PA. There were 7 bilateral implants. Intraoperative complications: hemorrhage. Complications after surgery: vertigo and internal device failure. In 7 patients the electrodes were implanted through. Telemetry showed satisfactory neural response and impedance. CT and MRI was performed in all patients. We found enlargement of the vestibular aqueduct in a patient and incudomalleolar malformation. Conclusion: The cochlear implant as a form of auditory rehabilitation is well established and spreading to different centers specialized in otoaudiology. Thus, the need for structured services and trained professionals in this type of procedure is clear. PMID:25991976

  7. Without Turning A Hair

    Institute of Scientific and Technical Information of China (English)

    周立

    2003-01-01

    [英语对话] A:You see,our happiness depends on other people,and theirs depends on us, too. B:I know the philosophy.but in practice many things do not work that way. A:You don’t care?What about when people are trying to enrage you? B:I remain as what I am without turning a hair,of course.[对话译文

  8. Hair Styling Appliances

    Science.gov (United States)

    1984-01-01

    Key tool of Redken Laboratories new line of hair styling appliances is an instrument called a thermograph, a heat sensing device originally developed by Hughes Aircraft Co. under U.S. Army and NASA funding. Redken Laboratories bought one of the early models of the Hughes Probeye Thermal Video System or TVS which detects the various degrees of heat emitted by an object and displays the results in color on a TV monitor with colors representing different temperatures detected.

  9. Normal and aging hair biology and structure 'aging and hair'.

    Science.gov (United States)

    Goodier, Molly; Hordinsky, Maria

    2015-01-01

    Much like an individual's hairstyle, hair fibers along the scalp see a number of changes over the course of one's lifetime. As the decades pass, the shine and volume synonymous with youthful hair may give way to thin, dull, and brittle hair commonly associated with aging. These changes are a result of a compilation of genetic and environmental elements influencing the cells of the hair follicle, specifically the hair follicle stem cells and melanocytes. Telomere shortening, decrease in cell numbers, and particular transcription factors have all been implicated in this process. In turn, these molecular alterations lead to structural modifications of the hair fiber, decrease in melanin production, and lengthening of the telogen phase of the hair cycle. Despite this inevitable progression with aging, there exists an array of treatments such as light therapy, minoxidil, and finasteride which have been designed to mitigate the effects of aging, particularly balding and thinning hair. Although each works through a different mechanism, all aim to maintain or potentially restore the youthful quality of hair.

  10. Rotating black hole hair

    CERN Document Server

    Gregory, Ruth; Wills, Danielle

    2013-01-01

    A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that a such a system displays much richer phenomenology than its static Schwarzschild or Reissner--Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: Large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is con...

  11. Effects of Delayed Second Cochlear Implant

    Institute of Scientific and Technical Information of China (English)

    XIA Rui-ming; WU Xi-hong; JANG Zi-gang; JING Yuan-yuan; LIN Yun-juan; YU Li-sheng

    2006-01-01

    Objective Since Helms' successful bilateral cochlear implantation with good results in 1996, there have been increasing number of reports on bilateral cochlear implantation. Most second device have been implantated within one year after the first. Considering effects of long time auditory deprivation, it is not clear whether a delayed second cochlear implant serves to add additional benefits and how it may interact with central nervous system plasticity. Methods Three cases who received delayed second cochlear implants at People's Hospital of Peking University from 2002 to 2005 were reviewed. The interval between the first and second implants was longer than 2 years in all three patients. Sound perception, and unilateral/bilateral speech discrimination in quiet and noise were evaluated. In addition, GAP detection test was conducted in one patient. Results In one case,having both implants on provided improved performance compared to using only one implant both in quiet and noise. Presumably due to visual interference from lip-reading or short interval between second implant and testing,one patient showed no improvement from using the second implant either in quiet or noise, while the last case demonstrated additional benefits from the second implant only in quiet. In all three patients, performance in recognizing the four tones in Mandarin was superior over word recognition. Conclusions Considerable plasticity in the cerebral auditory center is preserved, despite long acoustic deprivation in some children who have received unilateral cochlear implant. Delayed second implants can result in significant improvements in some of these children. Visual interference from lip-reading may be an obstacle during retraining. The better recognition of tones in the Mandarin language may represent a different sound discrimination mechanism in the auditory system,although it may also be related to the signal processing mechanisms of the implant used (MED-EL COMBI 40+).

  12. Prenatal Low Dosage Dioxin (TCDD) Exposure Impairs Cochlear Function Resulting in Auditory Neuropathy

    Science.gov (United States)

    Safe, Theresa M.; Luebke, Anne E.

    2015-01-01

    2,3,7,8-tetrachorodibenzo-p-dioxin (TCDD), a ubiquitous and persistent environmental contaminant, is a potent teratogen. Whereas developmental TCDD toxicity is mediated by the aryl hydrocarbon receptor (AhR), the normal function of the AhR is poorly understood. We tested whether dioxin exposure during a critical period of hair cell development disrupts cochlear function in three mouse strains, (C57BL6, BalbC, and CBA) that contain high affinity AhR-b alleles. C57BL/6, BalbC, and CBA dams were exposed to 500 ng/kg TCDD or olive oil (vehicle) on embryonic day 12 by gavage. Cochlear function was analyzed at 1.5 months of age by measuring 1) auditory brainstem response (ABRs) to tone pips from 5.6 to 30 kHz, and 2) distortion-product otoacoustic emissions (DPOAEs) evoked by primaries with f2 at the same frequency values. Cochlear threshold sensitivity following TCDD exposure was significantly elevated in both female and male mice in the C57BL/6 strain, carrying the Ahb-1 allele, but not significantly elevated in the BalbC or CBA strains, carrying the Ahb-2 allele. These ABR threshold deficits in mice carrying the Ahb-1 allele parallels the cleft palate incidence to higher TCDD exposures, suggesting that ABR testing could serve as a sensitive indicator of TCDD toxicity in at-risk children. Moreover, DPOAEs were not affected following TCDD exposure in any of the mouse strains, suggesting that following TCDD exposure mice with the Ahb-1 allele exhibit a mild auditory neuropathy. The causes of many auditory neuropathies are unknown, yet a developmental exposure to dioxin may be a risk factor for this condition. PMID:26464051

  13. Prenatal low dosage dioxin (TCDD) exposure impairs cochlear function resulting in auditory neuropathy.

    Science.gov (United States)

    Safe, Theresa M; Luebke, Anne E

    2016-01-01

    2,3,7,8-tetrachorodibenzo-p-dioxin (TCDD), a ubiquitous and persistent environmental contaminant, is a potent teratogen. Whereas developmental TCDD toxicity is mediated by the aryl hydrocarbon receptor (AhR), the normal function of the AhR is poorly understood. We tested whether dioxin exposure during a critical period of hair cell development disrupts cochlear function in three mouse strains, (C57BL6, BalbC, and CBA) that contain high affinity AhR-b alleles. C57BL/6, BalbC, and CBA dams were exposed to 500 ng/kg TCDD or olive oil (vehicle) on embryonic day 12 by gavage. Cochlear function was analyzed at 1.5 months of age by measuring 1) auditory brainstem response (ABRs) to tone pips from 5.6 to 30 kHz, and 2) distortion-product otoacoustic emissions (DPOAEs) evoked by primaries with f2 at the same frequency values. Cochlear threshold sensitivity following TCDD exposure was significantly elevated in both female and male mice in the C57BL/6 strain, carrying the Ahb-1 allele, but not significantly elevated in the BalbC or CBA strains, carrying the Ahb-2 allele. These ABR threshold deficits in mice carrying the Ahb-1 allele parallels the cleft palate incidence to higher TCDD exposures, suggesting that ABR testing could serve as a sensitive indicator of TCDD toxicity in at-risk children. Moreover, DPOAEs were not affected following TCDD exposure in any of the mouse strains, suggesting that following TCDD exposure mice with the Ahb-1 allele exhibit a mild auditory neuropathy. The causes of many auditory neuropathies are unknown, yet a developmental exposure to dioxin may be a risk factor for this condition.

  14. Hair removal on dermoscopy images.

    Science.gov (United States)

    Maglogiannis, Ilias; Delibasis, Kostantinos

    2015-08-01

    Digital Dermoscopy is a tool commonly used by dermatologists for assisting the diagnosis of skin lesions. The presence of hair in such dermoscopic images frequently occludes significant diagnostic information and reduces their value. In this work we propose algorithms that successfully identify and remove hair from the dermoscopic images. The proposed algorithms consist of two parts; the first deals with the identification of hair, while the second part concerns the image restoration using interpolation. For the evaluation of the algorithms we used ground truth images with synthetic hair and compared the results with the commonly used in the literature DullRazor tool. According to the experimental results the proposed hair removal algorithms can be used successfully in the detection and removal of both dark and light colored hair.

  15. [Neurocutaneous syndrome with hair alterations].

    Science.gov (United States)

    Camacho-Martínez, F

    1997-09-01

    There are multiple neurocutaneous syndromes that may show hair alterations such as the interglabellar peak or 'widow's peak', which is an alteration of the hair implantation, in addition to the genohypotrichosis, hypertrichosis and hair shaft dysplasias. In this chapter we will focus on the latter. Out of the unspecific hair shaft dysplasias the only ones showing neurological alterations are trichorrhexis invaginata, observed in the syndrome of Netherton. Among the specific dysplasias we would like to point out monilethrix, and very especially the moniliform hair syndrome, the trichorrhexis nodosa, the pili torti and trichotiodystrophy. The latter is actually a group of syndromes which associates a series of diverse symptoms that have in common hair brittleness, fertility problems and physical and mental retardation, and they constitute the basic syndrome know as 'BIDS syndrome.

  16. Distribution of Vesicular Glutamate Transporter 2 and Ionotropic Glutamate Receptors in the Auditory Ganglion and Cochlear Nuclei of Pigeons (Columba livia).

    Science.gov (United States)

    Karim, M R; Atoji, Y

    2016-02-01

    Glutamate is a principal excitatory neurotransmitter in the auditory system. Our previous studies revealed localization of glutamate receptor mRNAs in the pigeon cochlear nuclei, suggesting the existence of glutamatergic input from the auditory nerve to the brainstem. This study demonstrated localization of mRNAs for vesicular glutamate transporter 2 (vGluT2) and ionotropic glutamate receptors (AMPA, kainate and NMDA) in the auditory ganglion (AG) and cochlear nuclei (magnocellular, angular and laminar nuclei). VGluT2 mRNA was intensely expressed in AG and intensely or moderately in the cochlear nuclei. The AG and cochlear nuclei showed intense-to-moderate mRNA signals for GluA2, GluA3, GluA4, GluK4 and GluN1. These results suggest that the pigeon AG neurons receives glutamatergic input from hair cells and in turn projects to the magnocellular and angular nuclei. Glutamate may play a pivotal role in the excitatory synapse transmission in the peripheral auditory pathway of birds.

  17. Cochlear NMDA Receptors as a Therapeutic Target of Noise-Induced Tinnitus

    Directory of Open Access Journals (Sweden)

    Dan Bing

    2015-03-01

    Full Text Available Background: Accumulating evidence suggests that tinnitus may occur despite normal auditory sensitivity, probably linked to partial degeneration of the cochlear nerve and damage of the inner hair cell (IHC synapse. Damage to the IHC synapses and deafferentation may occur even after moderate noise exposure. For both salicylate- and noise-induced tinnitus, aberrant N-methyl-d-aspartate (NMDA receptor activation and related auditory nerve excitation have been suggested as origin of cochlear tinnitus. Accordingly, NMDA receptor inhibition has been proposed as a pharmacologic approach for treatment of synaptopathic tinnitus. Methods: Round-window application of the NMDA receptor antagonist AM-101 (Esketamine hydrochloride gel; Auris Medical AG, Basel, Switzerland was tested in an animal model of tinnitus induced by acute traumatic noise. The study included the quantification of IHC ribbon synapses as a correlate for deafferentation as well as the measurement of the auditory brainstem response (ABR to close-threshold sensation level stimuli as an indication of sound-induced auditory nerve activity. Results: We have shown that AM-101 reduced the trauma-induced loss of IHC ribbons and counteracted the decline of ABR wave I amplitude generated in the cochlea/auditory nerve. Conclusion: Local round-window application of AM-101 may be a promising therapeutic intervention for the treatment of synaptopathic tinnitus.

  18. Adult human nasal mesenchymal-like stem cells restore cochlear spiral ganglion neurons after experimental lesion.

    Science.gov (United States)

    Bas, Esperanza; Van De Water, Thomas R; Lumbreras, Vicente; Rajguru, Suhrud; Goss, Garrett; Hare, Joshua M; Goldstein, Bradley J

    2014-03-01

    A loss of sensory hair cells or spiral ganglion neurons from the inner ear causes deafness, affecting millions of people. Currently, there is no effective therapy to repair the inner ear sensory structures in humans. Cochlear implantation can restore input, but only if auditory neurons remain intact. Efforts to develop stem cell-based treatments for deafness have demonstrated progress, most notably utilizing embryonic-derived cells. In an effort to bypass limitations of embryonic or induced pluripotent stem cells that may impede the translation to clinical applications, we sought to utilize an alternative cell source. Here, we show that adult human mesenchymal-like stem cells (MSCs) obtained from nasal tissue can repair spiral ganglion loss in experimentally lesioned cochlear cultures from neonatal rats. Stem cells engraft into gentamicin-lesioned organotypic cultures and orchestrate the restoration of the spiral ganglion neuronal population, involving both direct neuronal differentiation and secondary effects on endogenous cells. As a physiologic assay, nasal MSC-derived cells engrafted into lesioned spiral ganglia demonstrate responses to infrared laser stimulus that are consistent with those typical of excitable cells. The addition of a pharmacologic activator of the canonical Wnt/β-catenin pathway concurrent with stem cell treatment promoted robust neuronal differentiation. The availability of an effective adult autologous cell source for inner ear tissue repair should contribute to efforts to translate cell-based strategies to the clinic.

  19. Bleaching of Black Human Hair

    Institute of Scientific and Technical Information of China (English)

    林琳

    2001-01-01

    Bleaching of black human hair has been studied systematically. On the basis of experimental data the technology of human hair bleaching through five processes was established. The optimum technology of improving the whiteness and reducing damage on fibers has been found. The technology can provide good luster,smooth handle and relatively high strength retention to human hair used for wigs or drama articles, meeting the needs of people better. Moreover, it also has important reference value to bleaching of other colored fibers.

  20. The amazing miniorgan: Hair follicle

    Directory of Open Access Journals (Sweden)

    Çiler Çelik Özenci

    2014-06-01

    Full Text Available Hair is a primary characteristic of mammals, and exerts a wide range of functions including thermoregulation, physical protection, sensory activity, and social interactions. The hair shaft consists of terminally differentiated keratinocytes that are produced by the hair follicle. Hair follicle development takes place during fetal skin development and relies on tightly regulated ectodermal–mesodermal interactions. Hair follicles form during embryonic development and, after birth, undergo recurrent cycling of growth (anagen, apoptosis-driven regression (catagen, and relative quiescence (telogen. As a functional mini-organ, the hair follicle develops in an environment with dynamic and alternating changes of diverse molecular signals. Our molecular understanding of hair follicle biology relies heavily on genetically engineered mouse models with abnormalities in hair structure, growth, and/or pigmentation and significant advances have been made toward the identification of key signaling pathways and the regulatory genes involved. In this review, the basic concepts of hair follicle, a mini-complex organ, biology will be presented and its importance in clinical applications will be summarized.

  1. The antioxidant activity of propofol in chicks

    Directory of Open Access Journals (Sweden)

    A.S. Naser

    2015-06-01

    Full Text Available The aim of this study was to detect the antioxidant effects of propofol in chicks by estimation of glutathione concentration in blood plasma, brain and liver as well as total antioxidant capacity and antioxidant effects of propofol in vitro by using hydrogen peroxide as oxidative stress. Propofol at 20 mg/kg, intraperitoneally significantly increased after 4 hours the concentration of glutathione concentration in plasma and brain compared with the control group and with 5 and 10mg propofol groups. Propofol at 5, 10 and 20 mg/kg, i.p significantly increased glutathione concentration in the liver compared with the control group. Propofol at 5, 10 and 20 mg/kg, i.p increased the efflux rate constant by 882, 1031 and 920 %, increased glutathione turnover rate by 880, 1028, and 917 % and decreased the turnover time by 89, 91 and 90% in the liver. In the brain propofol at 5, 10 and 20 mg/kg, i.p increased efflux rate constant as 26, 600 and 2826 % and increased glutathione turnover rate by 29, 616 and 2894 % and a decreased in the turnover time by 21, 86 and 96%. propofol at 10 and 20 mg/kg, i.p significantly increased after 20 hours the TAC in the serum of the chick by 38 and 48%, respectively compared with the control group. Propofol at concentrations of 25, 50 and 100 micromoles / liter decreased erythrocyte hemolysis induced by hydrogen peroxide in vitro 10 micromoles / liter in a concentration depended manner by 25, 49 and 64 % respectively. In conclusion, propofol have antioxidant effect in vivo and in vitro in the chicks.Propofol have a protection against oxidative stress.

  2. Genetics Home Reference: cartilage-hair hypoplasia

    Science.gov (United States)

    ... Home Health Conditions cartilage-hair hypoplasia cartilage-hair hypoplasia Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Cartilage-hair hypoplasia is a disorder of bone growth characterized by ...

  3. Removing Pubic Hair (For Young Women)

    Science.gov (United States)

    ... are special reasons you shouldn’t shave your pubic hair. Call your health care provider if you develop folliculitis or symptoms of infection. Tags: body hair , shaving Related Content Hair Removal I can see tiny black spots under my ...

  4. Prevalence of inner ear anomalies among cochlear implant candidates

    OpenAIRE

    Aldhafeeri, Ahmad M.; Alsanosi, Abdulrahman A.

    2016-01-01

    Objectives: To determine the prevalence of inner ear anomalies and the frequency of different anomaly types among cochlear implant recipients. Methods: This study included a retrospective chart review of all patients who received cochlear implants between January 2009 and January 2013 in King Abdulaziz University Hospital cochlear implant program in Riyadh, Saudi Arabia. All subjects underwent thin-cut CT of the temporal bone and MRI. The collected data included age, gender, and CT and MRI fi...

  5. INDICATION AND SURGICAL CONSIDERATION OF COCHLEAR IMPLANTATION AT WAHIDIN HOSPITAL

    OpenAIRE

    Savitri, Eka

    2014-01-01

    OBJECTIVES To demonstrate selection criteria for cochlear implant candidates as well as the outcome of quality of life (QoL) after cochlearimplant surgery. MATERIAL AND METHOD Retrospective review was performed of all cochlear implants at Wahidin Hospital. A total number of 5 cochlear implantations were performed during the period of April 2003 to April 2004. Inclusion criteria were established and the audiological criteria were then evaluated using the OAE, BERA and ASSR test. The e...

  6. Measuring the style of chick lit and literature

    NARCIS (Netherlands)

    Jautze, K.J.

    2014-01-01

    This paper examines to what extent the distribution of the hundred most frequent function words of two novelistic genres (chick lit and literature) gives insight into the genre styles. The results shows that the literary style is more descriptive and informational, whereas the style of the chick-lit

  7. Killing day-old chicks? Public opinion regarding potential alternatives

    NARCIS (Netherlands)

    Leenstra, F.; Munnichs, G.M.; Beekman, V.; Vromans, E.; Aramyan, L.; Woelders, H.

    2011-01-01

    Throughout the world, male chicks from layer breeds are killed just after hatching, as they are not profitable as regards the production of meat. The Dutch and European parliaments have insisted on research into possible alternatives to the killing of day-old chicks. In the present study we have inv

  8. Smokers′ hair: Does smoking cause premature hair graying?

    Directory of Open Access Journals (Sweden)

    Ayman A Zayed

    2013-01-01

    Full Text Available Aims: To determine if there is a significant association between premature hair graying and cigarette smoking. Materials and Methods: A cross-sectional observational study was conducted in a nonclinical setting on 207 participants on August 24 until 25, 2010. Participants were classified into two groups [premature hair graying (PHG and normal hair graying]. PHG was defined as the first appearance of gray hair before the age of 30. Data were collected using an interview questionnaire and measurements of body mass index, waist circumference, fasting blood glucose and blood pressure. Collected data were statistically analyzed using SPSS 16, Chicago, IL. Results: Of the 207 subjects, 104 (50.2% had first appearance of gray hair before the age of 30 (PHG group while the other 103 (49.8% were considered normal hair graying group. The prevalence of smokers in the "PHG" group was higher (40.2% vs. 24.7%, P = 0.031. Smokers had earlier onset of hair graying (smokers: 31 (7.4 vs. nonsmokers: 34 (8.6, P = 0.034. Using multiple logistic regression with conditional likelihood, smokers were two and half times (95% CI: 1.5-4.6 more prone to develop PHG. Conclusion: This study suggests that there is a significant relation (with adjusted odds ratio of two and half between onset of gray hair before the age of 30 and cigarette smoking.

  9. Dopaminergic modulation of the voltage-gated sodium current in the cochlear afferent neurons of the rat.

    Directory of Open Access Journals (Sweden)

    Catalina Valdés-Baizabal

    Full Text Available The cochlear inner hair cells synapse onto type I afferent terminal dendrites, constituting the main afferent pathway for auditory information flow. This pathway receives central control input from the lateral olivocochlear efferent neurons that release various neurotransmitters, among which dopamine (DA plays a salient role. DA receptors activation exert a protective role in the over activation of the afferent glutamatergic synapses, which occurs when an animal is exposed to intense sound stimuli or during hypoxic events. However, the mechanism of action of DA at the cellular level is still not completely understood. In this work, we studied the actions of DA and its receptor agonists and antagonists on the voltage-gated sodium current (INa in isolated cochlear afferent neurons of the rat to define the mechanisms of dopaminergic control of the afferent input in the cochlear pathway. Experiments were performed using the voltage and current clamp techniques in the whole-cell configuration in primary cultures of cochlear spiral ganglion neurons (SGNs. Recordings of the INa showed that DA receptor activation induced a significant inhibition of the peak current amplitude, leading to a significant decrease in cell excitability. Inhibition of the INa was produced by a phosphorylation of the sodium channels as shown by the use of phosphatase inhibitor that produced an inhibition analogous to that caused by DA receptor activation. Use of specific agonists and antagonists showed that inhibitory action of DA was mediated both by activation of D1- and D2-like DA receptors. The action of the D1- and D2-like receptors was shown to be mediated by a Gαs/AC/cAMP/PKA and Gαq/PLC/PKC pathways respectively. These results showed that DA receptor activation constitutes a significant modulatory input to SGNs, effectively modulating their excitability and information flow in the auditory pathway.

  10. Dopaminergic modulation of the voltage-gated sodium current in the cochlear afferent neurons of the rat.

    Science.gov (United States)

    Valdés-Baizabal, Catalina; Soto, Enrique; Vega, Rosario

    2015-01-01

    The cochlear inner hair cells synapse onto type I afferent terminal dendrites, constituting the main afferent pathway for auditory information flow. This pathway receives central control input from the lateral olivocochlear efferent neurons that release various neurotransmitters, among which dopamine (DA) plays a salient role. DA receptors activation exert a protective role in the over activation of the afferent glutamatergic synapses, which occurs when an animal is exposed to intense sound stimuli or during hypoxic events. However, the mechanism of action of DA at the cellular level is still not completely understood. In this work, we studied the actions of DA and its receptor agonists and antagonists on the voltage-gated sodium current (INa) in isolated cochlear afferent neurons of the rat to define the mechanisms of dopaminergic control of the afferent input in the cochlear pathway. Experiments were performed using the voltage and current clamp techniques in the whole-cell configuration in primary cultures of cochlear spiral ganglion neurons (SGNs). Recordings of the INa showed that DA receptor activation induced a significant inhibition of the peak current amplitude, leading to a significant decrease in cell excitability. Inhibition of the INa was produced by a phosphorylation of the sodium channels as shown by the use of phosphatase inhibitor that produced an inhibition analogous to that caused by DA receptor activation. Use of specific agonists and antagonists showed that inhibitory action of DA was mediated both by activation of D1- and D2-like DA receptors. The action of the D1- and D2-like receptors was shown to be mediated by a Gαs/AC/cAMP/PKA and Gαq/PLC/PKC pathways respectively. These results showed that DA receptor activation constitutes a significant modulatory input to SGNs, effectively modulating their excitability and information flow in the auditory pathway.

  11. Basic fibroblast growth factor protects auditory neurons and hair cells from noise exposure and glutamate neurotoxicity

    Institute of Scientific and Technical Information of China (English)

    翟所强; 王大君; 王嘉陵

    2003-01-01

    The purpose of the present study was to determine protectivie effects of basic fibroblast growth factor (bFGF) on cochlear neurons and hair cells in vitro and in vivo. In experiment I, cultured spiral ganglion neurons (SGNs) prepared from P3 mice were exposed to 20mM glutamate for 2 hours before the culture medium was replaced with fresh medium containing 0, 25, 50, and 100 ng/ml bFGF, respectively. Fourteen days later, all cultures were fixed with 4% paraformaldehyde, and stained with 1% toluidine blue. The number of surviving SGNs were counted and the length of SGNs neurites were measured. Exposure to 20 mM glutamate for 24 hours resulted in an inhibition on neurite outgrowth of SGNs and elevated cell death. Treatment of the cultures with bFGF led to promotion of neurite outgrowth and elevated number of surviving SGNs. Effects of bFGF were dose dependent with the highest potency at 100 ng/ml. In experiment Ⅱ, in vivo studies were carried out with guinea pigs in which bFGF or artificial perilymph was perfused into the cochlea to assess possible protective effects of bFGF on cochlear hair cells and compound action potentials(CAP). The CAPs were measured before, immediatly and 48 hours after exposure to noise. Significant differences in CAP were observed (p<0. 05 ) among the bFGF perfused group, control group(t =3. 896 ) and artificial perilymph perfused group (t =2. 520) at 48 hours after noise exposure, Cochleae were removed and hair cell Loss was analyzed in surface preparations prepared from all experimental animals. Acoustic trauma caused loss of 651 and 687 inner hair cells in the control and artificial perilymph perfused group, respectively. In sharp contrast, only 31 inner hair cells were lost in the bFGF perfused ears. Similarly, more outer hair cells died in the control and perilymph perfuesed group (41830 and 41968, respectively) than in the group treated with bFGF (34258). Our results demonstrate that bFGF protected SGNs against glutmate

  12. Transcriptomic Analysis of Mouse Cochlear Supporting Cell Maturation Reveals Large-Scale Changes in Notch Responsiveness Prior to the Onset of Hearing

    Science.gov (United States)

    Maass, Juan C.; Gu, Rende; Cai, Tiantian; Wan, Ying-Wooi; Cantellano, Silvia C.; Asprer, Joanna S. T.; Zhang, Hongyuan; Jen, Hsin-I; Edlund, Renée K.; Liu, Zhandong; Groves, Andrew K.

    2016-01-01

    Neonatal mouse cochlear supporting cells have a limited ability to divide and trans-differentiate into hair cells, but this ability declines rapidly in the two weeks after birth. This decline is concomitant with the morphological and functional maturation of the organ of Corti prior to the onset of hearing. However, despite this association between maturation and loss of regenerative potential, little is known of the molecular changes that underlie these events. To identify these changes, we used RNA-seq to generate transcriptional profiles of purified cochlear supporting cells from 1- and 6-day-old mice. We found many significant changes in gene expression during this period, many of which were related to regulation of proliferation, differentiation of inner ear components and the maturation of the organ of Corti prior to the onset of hearing. One example of a change in regenerative potential of supporting cells is their robust production of hair cells in response to a blockade of the Notch signaling pathway at the time of birth, but a complete lack of response to such blockade just a few days later. By comparing our supporting cell transcriptomes to those of supporting cells cultured in the presence of Notch pathway inhibitors, we show that the transcriptional response to Notch blockade disappears almost completely in the first postnatal week. Our results offer some of the first molecular insights into the failure of hair cell regeneration in the mammalian cochlea. PMID:27918591

  13. Investigation of hair dye deposition, hair color loss, and hair damage during multiple oxidative dyeing and shampooing cycles.

    Science.gov (United States)

    Zhang, Guojin; McMullen, Roger L; Kulcsar, Lidia

    2016-01-01

    Color fastness is a major concern for consumers and manufacturers of oxidative hair dye products. Hair dye loss results from multiple wash cycles in which the hair dye is dissolved by water and leaches from the hair shaft. In this study, we carried out a series of measurements to help us better understand the kinetics of the leaching process and pathways associated with its escape from the fiber. Hair dye leaching kinetics was measured by suspending hair in a dissolution apparatus and monitoring the dye concentration in solution (leached dye) with an ultraviolet-visible spectrophotometer. The physical state of dye deposited in hair fibers was evaluated by a reflectance light microscopy technique, based on image stacking, allowing enhanced depth of field imaging. The dye distribution within the fiber was monitored by infrared spectroscopic imaging of hair fiber cross sections. Damage to the ultrafine structure of the hair cuticle (surface, endocuticle, and cell membrane complex) and cortex (cell membrane complex) was determined in hair cross sections and on the hair fiber surface with atomic force microscopy. Using differential scanning calorimetry, we investigated how consecutive coloring and leaching processes affect the internal proteins of hair. Further, to probe the surface properties of hair we utilized contact angle measurements. This study was conducted on both pigmented and nonpigmented hair to gain insight into the influence of melanin on the hair dye deposition and leaching processes. Both types of hair were colored utilizing a commercial oxidative hair dye product based on pyrazole chemistry.

  14. Guidelines for laser hair removal.

    Science.gov (United States)

    Casey, Angela S; Goldberg, David

    2008-03-01

    Requests for removal of unwanted body hair are common in dermatologic and surgical practices. Technology continues to improve the achievement of a more permanent reduction through the use of lasers. Despite the increased use of lasers, to date, few guidelines exist in terms of how to approach laser hair removal. Specifically, one must understand the mechanism of hair growth and how lasers work to target the hair follicle. There is significant variation among practitioners in pre-and post-laser recommendations to patients as well as intervals between treatment sessions. We performed a thorough review of the literature in order to determine evidence for the ideal interval between treatment sessions and the ideal number of sessions. We also sought to establish, based on published reports, the recommendations for shaving, plucking, waxing or other hair removal methods prior to laser hair removal and the guidelines for sun exposure before and after laser treatments. Finally, we searched the literature to find out whether there are areas that should not be treated with laser hair removal. The evidence and recommendations in this article aim to help guide practitioners in their approach to laser hair removal.

  15. Professionalizing hair care in Tonga

    NARCIS (Netherlands)

    N. Besnier

    2013-01-01

    In the course of the last two decades, Nuku'alofa, the capital of Tonga, witnessed an explosion of a particular kind of business, hair salons. For owners, workers, and customers alike, hair salons represent modernity and cosmopolitanism, and they thus attract a particular kind of clientele and labou

  16. "Dissection" of a Hair Dryer

    Science.gov (United States)

    Eisenstein, Stan; Simpson, Jeff

    2008-01-01

    The electrical design of the common hair dryer is based almost entirely on relatively simple principles learned in introductory physics classes. Just as biology students dissect a frog to see the principles of anatomy in action, physics students can "dissect" a hair dryer to see how principles of electricity are used in a real system. They can…

  17. The Effects of DPPH on Cochlear Microcirculation

    Institute of Scientific and Technical Information of China (English)

    孔维佳; 陈敏

    2003-01-01

    Summary: To investigate the effects of the free radical, 1,1-Diphenyl-2-picylhydrazyl, on cochlearblood flow, 20 guinea pigs were divided into 3 groups at random, 6 for control group, 6 for 1 mmol/L group and 8 for 0. 1 mmol/L group. 2μl vehicle or drugs were dropped into round window mem-brane (RWM). Cochlear microcirculation was monitored by laser Doppler flowmeter (LDF), andmean arterial blood flow (MABP), which was transferred by pressure conductor sensor and preampli-fier, was simultaneously recorded on the computer. Our results showed that MABP was stablethroughout the experiment. Cochlear blood flow (CBF) increased by 10. 32 % (P<0. 05) in 1mmol/L group, and decreased by 4. 89 % in 0. 1 mmol/L group (P<0. 05). In control groupcochlear microcirculation showed no significant changes. It is concluded that DPPH exerted effects oncochlear microcirculation.

  18. Cochlear implant: what the radiologist should know

    OpenAIRE

    Natalia Delage Gomes; Caroline Laurita Batista Couto; Juliana Oggioni Gaiotti; Ana Maria Doffemond Costa; Marcelo Almeida Ribeiro; Renata Lopes Furletti Caldeira Diniz

    2013-01-01

    Cochlear implant is the method of choice in the treatment of deep sensorineural hypoacusis, particularly in patients where conventional amplification devices do not imply noticeable clinical improvement. Imaging findings are crucial in the indication or contraindication for such surgical procedure. In the assessment of the temporal bone, radiologists should be familiar with relative or absolute contraindication factors, as well as with factors that might significantly complicate the implantat...

  19. Accurate guitar tuning by cochlear implant musicians.

    Science.gov (United States)

    Lu, Thomas; Huang, Juan; Zeng, Fan-Gang

    2014-01-01

    Modern cochlear implant (CI) users understand speech but find difficulty in music appreciation due to poor pitch perception. Still, some deaf musicians continue to perform with their CI. Here we show unexpected results that CI musicians can reliably tune a guitar by CI alone and, under controlled conditions, match simultaneously presented tones to electric analysis, showed that accurate tuning was achieved by listening to beats rather than discriminating pitch, effectively turning a spectral task into a temporal discrimination task.

  20. Genuine cosmic hair

    Science.gov (United States)

    Kastor, David; Ray, Sourya; Traschen, Jennie

    2017-02-01

    We show that asymptotically future de Sitter (AFdS) spacetimes carry ‘genuine’ cosmic hair; information that is analogous to the mass and angular momentum of asymptotically flat spacetimes and that characterizes how an AFdS spacetime approaches its asymptotic form. We define new ‘cosmological tension’ charges associated with future asymptotic spatial translation symmetries, which are analytic continuations of the ADM mass and tensions of asymptotically planar AdS spacetimes, and which measure the leading anisotropic corrections to the isotropic, exponential de Sitter expansion rate. A cosmological Smarr relation, holding for AFdS spacetimes having exact spatial translation symmetry, is derived. This formula relates cosmological tension, which is evaluated at future infinity, to properties of the cosmology at early times, together with a ‘cosmological volume’ contribution that is analogous to the thermodynamic volume of AdS black holes. Smarr relations for different spatial directions imply that the difference in expansion rates between two directions at late times is related in a simple way to their difference at early times. Hence information about the very early universe can be inferred from cosmic hair, which is potentially observable in a late time de Sitter phase. Cosmological tension charges and related quantities are evaluated for Kasner–de Sitter spacetimes, which serve as our primary examples.

  1. Role for a novel Usher protein complex in hair cell synaptic maturation.

    Directory of Open Access Journals (Sweden)

    Marisa Zallocchi

    Full Text Available The molecular mechanisms underlying hair cell synaptic maturation are not well understood. Cadherin-23 (CDH23, protocadherin-15 (PCDH15 and the very large G-protein coupled receptor 1 (VLGR1 have been implicated in the development of cochlear hair cell stereocilia, while clarin-1 has been suggested to also play a role in synaptogenesis. Mutations in CDH23, PCDH15, VLGR1 and clarin-1 cause Usher syndrome, characterized by congenital deafness, vestibular dysfunction and retinitis pigmentosa. Here we show developmental expression of these Usher proteins in afferent spiral ganglion neurons and hair cell synapses. We identify a novel synaptic Usher complex comprised of clarin-1 and specific isoforms of CDH23, PCDH15 and VLGR1. To establish the in vivo relevance of this complex, we performed morphological and quantitative analysis of the neuronal fibers and their synapses in the Clrn1-/- mouse, which was generated by incomplete deletion of the gene. These mice showed a delay in neuronal/synaptic maturation by both immunostaining and electron microscopy. Analysis of the ribbon synapses in Ames waltzer(av3J mice also suggests a delay in hair cell synaptogenesis. Collectively, these results show that, in addition to the well documented role for Usher proteins in stereocilia development, Usher protein complexes comprised of specific protein isoforms likely function in synaptic maturation as well.

  2. Photodynamic therapy for hair removal

    Directory of Open Access Journals (Sweden)

    Mohamed H. M. Ali

    2013-05-01

    Full Text Available Background: Unwanted hair is one of the most common medical problems affecting women of reproductive age inducing a lot of psychological stress and threatening their femininity and self-esteem. Old methods of removing unwanted hair include shaving, waxing, chemical depilation, and electrolysis, all of which have temporary results. However laser-assisted hair removal is the most efficient method of long-term hair removal currently available. It is desirable to develop a reduced cost photodynamic therapy (PDT system whose properties should include high efficiency and low side-effects. Method: Mice skin tissues were used in this study and divided into six groups such as controls, free methylene blue (MB incubation, liposome methylene blue (MB incubation, laser without methylene blue (MB, free methylene blue (MB for 3 and 4 hrs and laser, liposome methylene blue (MB for 3 hrs and laser. Methylene blue (MBwas applied to wax epilated areas. The areas were irradiated with CW He-Ne laser system that emits orange-red light with wavelength 632.8 nm and 10 mW at energy density of 5 J/ cm2 for 10 minutes. The UV-visible absorption spectrum was collected by Cary spectrophotometer. Results: Methylene blue (MB is selectively absorbed by actively growing hair follicles due to its cationic property. Methylene blue (MBuntreated sections showed that hair follicle and sebaceous gland are intact and there is no change due to the laser exposure. Free methylene blue (MB sections incubated for 3 hrs showed that He:Ne laser induced destruction in hair follicles, leaving an intact epidermis. Treated section with free methylene blue (MB for 4 hrs showed degeneration and necrosis in hair follicle, leaving an intact epidermis. Liposomal methylene blue (MB sections incubated for 3 hrs showed He:Ne laser induced destruction in hair follicles with intradermal leucocytic infiltration. Conclusions: Low power CW He:Ne laser and methylene blue (MB offered a successful PDT system

  3. Harvesting electricity from human hair.

    Science.gov (United States)

    Tulachan, Brindan; Singh, Sushil K; Philip, Deepu; Das, Mainak

    2016-01-01

    Electrical conductivity of human hair is a debatable issue among hair experts and scientists. There are unsubstantiated claims that hair conducts electricity. However, hair experts provided ample evidence that hair is an insulator. Although wet hair exhibited drastic reduction in resistivity; scientists regarded hair as a proton semiconductor at the best. Here, we demonstrate that hair filaments generate electricity on absorbing water vapor between 50 degrees and 80 degrees C. This electricity can operate low power electronic systems. Essentially, we are exposing the hydrated hair polymer to a high temperature (50 degrees-80 degrees C). It has long been speculated that when certain biopolymers are simultaneously hydrated and exposed to high temperature, they exhibit significant proton hopping at a specific temperature regime. This happens due to rapid movement of water molecules on the polymer surface. This lead us to speculate that the observed flow of current is partly ionic and partly due to "proton hopping" in the hydrated nano spaces of hair filament. Such proton hopping is exceptionally high when the hydrated hair polymer is exposed to a temperature between 50 degrees and 80 degrees C. Differential scanning calorimetry data further corroborated the results and indicated that indeed at this temperature range, there is an enormous movement of water molecules on the hair polymer surface. This enormously rapid movement of water molecules lead to the "making and breaking" of innumerable hydrogen bonds and thus resulting in hopping of the protons. What is challenging is "how to tap these hopping protons to obtain useful electricity?" We achieved this by placing a bundle of hair between two different electrodes having different electro negativities, and exposing it to water vapor (water + heat). The two different electrodes offered directionality to the hopping protons and the existing ions and thus resulting in the generation of useful current. Further, by

  4. Quantitative analysis of ribbons, vesicles, and cisterns at the cat inner hair cell synapse: correlations with spontaneous rate.

    Science.gov (United States)

    Kantardzhieva, Albena; Liberman, M Charles; Sewell, William F

    2013-10-01

    Cochlear hair cells form ribbon synapses with terminals of the cochlear nerve. To test the hypothesis that one function of the ribbon is to create synaptic vesicles from the cisternal structures that are abundant at the base of hair cells, we analyzed the distribution of vesicles and cisterns around ribbons from serial sections of inner hair cells in the cat, and compared data from low and high spontaneous rate (SR) synapses. Consistent with the hypothesis, we identified a "sphere of influence" of 350 nm around the ribbon, with fewer cisterns and many more synaptic vesicles. Although high- and low-SR ribbons tended to be longer and thinner than high-SR ribbons, the total volume of the two ribbon types was similar. There were almost as many vesicles docked at the active zone as attached to the ribbon. The major SR-related difference was that low-SR ribbons had more synaptic vesicles intimately associated with them. Our data suggest a trend in which low-SR synapses had more vesicles attached to the ribbon (51.3 vs. 42.8), more docked between the ribbon and the membrane (12 vs. 8.2), more docked at the active zone (56.9 vs. 44.2), and more vesicles within the "sphere of influence" (218 vs. 166). These data suggest that the structural differences between high- and low-SR synapses may be more a consequence, than a determinant, of the physiological differences.

  5. Cochlear perfusion with a viscous fluid.

    Science.gov (United States)

    Wang, Yi; Olson, Elizabeth S

    2016-07-01

    The flow of viscous fluid in the cochlea induces shear forces, which could provide benefit in clinical practice, for example to guide cochlear implant insertion or produce static pressure to the cochlear partition or wall. From a research standpoint, studying the effects of a viscous fluid in the cochlea provides data for better understanding cochlear fluid mechanics. However, cochlear perfusion with a viscous fluid may damage the cochlea. In this work we studied the physiological and anatomical effects of perfusing the cochlea with a viscous fluid. Gerbil cochleae were perfused at a rate of 2.4 μL/min with artificial perilymph (AP) and sodium hyaluronate (Healon, HA) in four different concentrations (0.0625%, 0.125%, 0.25%, 0.5%). The different HA concentrations were applied either sequentially in the same cochlea or individually in different cochleae. The perfusion fluid entered from the round window and was withdrawn from basal scala vestibuli, in order to perfuse the entire perilymphatic space. Compound action potentials (CAP) were measured after each perfusion. After perfusion with increasing concentrations of HA in the order of increasing viscosity, the CAP thresholds generally increased. The threshold elevation after AP and 0.0625% HA perfusion was small or almost zero, and the 0.125% HA was a borderline case, while the higher concentrations significantly elevated CAP thresholds. Histology of the cochleae perfused with the 0.0625% HA showed an intact Reissner's membrane (RM), while in cochleae perfused with 0.125% and 0.25% HA RM was torn. Thus, the CAP threshold elevation was likely due to the broken RM, likely caused by the shear stress produced by the flow of the viscous fluid. Our results and analysis indicate that the cochlea can sustain, without a significant CAP threshold shift, up to a 1.5 Pa shear stress. Beside these finding, in the 0.125% and 0.25% HA perfusion cases, a temporary CAP threshold shift was observed, perhaps due to the presence and

  6. Exploring Perspectives on Cochlear Implants and Language Acquisition within the Deaf Community

    Science.gov (United States)

    Gale, Elaine

    2011-01-01

    Cochlear implants generated intense debate almost immediately following their introduction in the 1980s. Today, with a vast number of deaf individuals with cochlear implants, the debate about the cochlear implant device and mode of communication continues. Q-methodology was used in this study to explore cochlear implants and language acquisition…

  7. A Literature Analysis of Themes in Paediatric Cochlear Implant Research

    DEFF Research Database (Denmark)

    Hendar, Nils Ola Ebbe; Dammeyer, Jesper Herup

    2015-01-01

    Research on children with cochlear implants (CI) has documented positive outcomes, but also that many still experience language delays. The aim of this article is to explore how research on children with cochlear implants cover topics of early language development compared to research on children...

  8. An Introduction to Cochlear Implant Technology, Activation, and Programming.

    Science.gov (United States)

    Moore, Jan A.; Teagle, Holly F. B.

    2002-01-01

    This article provides information about the hardware components and speech-processing strategies of cochlear implant systems. The use of assistive listening devices with cochlear implants is also discussed. A brief description of surgical procedures and the initial activation of the device are also presented, along with programming considerations.…

  9. Surgical Management of the Pediatric Cochlear Implant Patient.

    Science.gov (United States)

    Cohen, Seth M.; Haynes, David S.

    2003-01-01

    This article discusses the surgical management of children receiving cochlear implants. It identifies preoperative considerations to select patients likely to benefit, contraindications, some new surgical techniques, complications, special considerations (otitis media, meningitis, head growth, inner ear malformations, and cochlear obstruction).…

  10. Evaluation of Evoked Potentials to Dyadic Tones after Cochlear Implantation

    Science.gov (United States)

    Sandmann, Pascale; Eichele, Tom; Buechler, Michael; Debener, Stefan; Jancke, Lutz; Dillier, Norbert; Hugdahl, Kenneth; Meyer, Martin

    2009-01-01

    Auditory evoked potentials are tools widely used to assess auditory cortex functions in clinical context. However, in cochlear implant users, electrophysiological measures are challenging due to implant-created artefacts in the EEG. Here, we used independent component analysis to reduce cochlear implant-related artefacts in event-related EEGs of…

  11. Speech Intelligibility and Prosody Production in Children with Cochlear Implants

    Science.gov (United States)

    Chin, Steven B.; Bergeson, Tonya R.; Phan, Jennifer

    2012-01-01

    Objectives: The purpose of the current study was to examine the relation between speech intelligibility and prosody production in children who use cochlear implants. Methods: The Beginner's Intelligibility Test (BIT) and Prosodic Utterance Production (PUP) task were administered to 15 children who use cochlear implants and 10 children with normal…

  12. Evaluating the Feasibility of Using Remote Technology for Cochlear Implants

    Science.gov (United States)

    Goehring, Jenny L.; Hughes, Michelle L.; Baudhuin, Jacquelyn L.

    2012-01-01

    The use of remote technology to provide cochlear implant services has gained popularity in recent years. This article contains a review of research evaluating the feasibility of remote service delivery for recipients of cochlear implants. To date, published studies have determined that speech-processor programming levels and other objective tests…

  13. Serving Deaf Students Who Have Cochlear Implants. PEPNet Tipsheet

    Science.gov (United States)

    Searls, J. Matt, Comp.

    2010-01-01

    Cochlear implants (CIs) are complex electronic devices surgically implanted under the skin behind the ear. These devices utilize electrodes placed in the inner ear (the cochlea) to stimulate the auditory nerve of individuals with significant permanent hearing loss. Cochlear implants may not be suitable for everyone. They are designed to provide…

  14. 28 CFR 551.4 - Hair length.

    Science.gov (United States)

    2010-07-01

    ... to an inmate hair care services which comply with applicable health and sanitation requirements. ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Hair length. 551.4 Section 551.4 Judicial... Hair length. (a) The Warden may not restrict hair length if the inmate keeps it neat and clean. (b)...

  15. Carcinogenicity of hair dye components.

    Science.gov (United States)

    Van Duuren, B L

    1980-03-01

    The available animal carcinogenicity data on hair dye components was reviewed. From this review it became clear that certain hair dye components, some of which are still in hair dye formulations now on the market, are animal carcinogens. The compounds of concern that are still in use are: 3-amino-4-methoxyaniline, 2-nitro-4-aminoaniline and 3-nitro-4-hydroxyaniline. Certain azo dyes formerly used, and related compounds still in use, contain the benzidine moiety. Two of these compounds, Direct Blue 6 and Direct Black 38, have been shown to be metabolized in animals to the human carcinogen benzidine. Furthermore, skin absorption studies carried out with radiolabeled hair dye components applied to animal or human skin have conclusively shown that these compounds are systemically absorbed and excreted. Known cocarcinogens such as catechol and pyrogallol, which enhance benzo(a)pyrene carcinogenicity on mouse skin, are used as hair dye components. It is not known whether such compounds will enhance the carcinogenicity of substituted aniline hair dye chemicals. The available epidemiologic data are not sufficient to link hair dye use with an increased incidence in human cancer.

  16. Proteomic Analysis of Hair Follicles

    Science.gov (United States)

    Ishioka, Noriaki; Terada, Masahiro; Yamada, Shin; Seki, Masaya; Takahashi, Rika; Majima, Hideyuki J.; Higashibata, Akira; Mukai, Chiaki

    2013-02-01

    Hair root cells actively divide in a hair follicle, and they sensitively reflect physical conditions. By analyzing the human hair, we can know stress levels on the human body and metabolic conditions caused by microgravity environment and cosmic radiation. The Japan Aerospace Exploration Agency (JAXA) has initiated a human research study to investigate the effects of long-term space flight on gene expression and mineral metabolism by analyzing hair samples of astronauts who stayed in the International Space Station (ISS) for 6 months. During long-term flights, the physiological effects on astronauts include muscle atrophy and bone calcium loss. Furthermore, radiation and psychological effects are important issue to consider. Therefore, an understanding of the effects of the space environment is important for developing countermeasures against the effects experienced by astronauts. In this experiment, we identify functionally important target proteins that integrate transcriptome, mineral metabolism and proteome profiles from human hair. To compare the protein expression data with the gene expression data from hair roots, we developed the protein processing method. We extracted the protein from five strands of hair using ISOGEN reagents. Then, these extracted proteins were analyzed by LC-MS/MS. These collected profiles will give us useful physiological information to examine the effect of space flight.

  17. Removal of unwanted facial hair.

    Science.gov (United States)

    Shenenberger, Donald W; Utecht, Lynn M

    2002-11-15

    Unwanted facial hair is a common problem that is seldom discussed in the primary care setting. Although men occasionally request removal of unwanted facial hair, women most often seek help with this condition. Physicians generally neglect to address the problem if the patient does not first request help. The condition may be caused by androgen overproduction, increased sensitivity to circulating androgens, or other metabolic and endocrine disorders, and should be properly evaluated. Options for hair removal vary in efficacy, degree of discomfort, and cost. Clinical studies on the efficacy of many therapies are lacking. Short of surgical removal of the hair follicle, the only permanent treatment is electrolysis. However, the practice of electrolysis lacks standardization, and regulation of the procedure varies from state to state. Shaving, epilation, and depilation are the most commonly attempted initial options for facial hair removal. Although these methods are less expensive, they are only temporary. Laser hair removal, although better studied than most methods and more strictly regulated, has yet to be proved permanent in all patients. Eflornithine, a topical treatment, is simple to apply and has minimal side effects. By the time most patients consult a physician, they have tried several methods of hair removal. Family physicians can properly educate patients and recommend treatment for this common condition if they are armed with basic knowledge about the treatment options.

  18. Black hole hair removal

    Science.gov (United States)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  19. Black Hole Hair Removal

    CERN Document Server

    Banerjee, Nabamita; Sen, Ashoke

    2009-01-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair, -- degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  20. Genuine Cosmic Hair

    CERN Document Server

    Kastor, David; Traschen, Jennie

    2016-01-01

    We show that asymptotically future deSitter (AFdS) spacetimes carry 'genuine' cosmic hair; information that is analogous to the mass and angular momentum of asymptotically flat spacetimes and that characterizes how an AFdS spacetime approaches its asymptotic form. We define new 'cosmological tension' charges associated with future asymptotic spatial translation symmetries, which are analytic continuations of the ADM mass and tensions of asymptotically planar AdS spacetimes, and which measure the leading anisotropic corrections to the isotropic, exponential deSitter expansion rate. A cosmological Smarr relation, holding for AFdS spacetimes having exact spatial translation symmetry, is derived. This formula relates cosmological tension, which is evaluated at future infinity, to properties of the cosmology at early times, together with a 'cosmological volume' contribution that is analogous to the thermodynamic volume of AdS black holes. Smarr relations for different spatial directions imply that the difference i...

  1. Contact Allergy to Hair Dyes

    Directory of Open Access Journals (Sweden)

    Marie-Louise Anna Schuttelaar

    2016-06-01

    Full Text Available Many strong and extreme sensitizing chemicals, such as para-phenylenediamine (PPD, toluene-2,5-diamine (TDA and other aromatic amines or cross-reacting substances, are ingredients in hair dye products. The chemistry of hair dyeing and the immunological reactions to the potent sensitizing hair dye components are complex and have not been fully clarified up until now. Recently 2-methoxymethyl-p-phenylenediamine (ME-PPD, a PPD derivate with moderate skin-sensitizing properties, was developed. Although developed for the prevention of sensitization, ME-PPD appears to be tolerated in some PPD/TDA-allergic individuals.

  2. The structure of people's hair.

    Science.gov (United States)

    Yang, Fei-Chi; Zhang, Yuchen; Rheinstädter, Maikel C

    2014-01-01

    Hair is a filamentous biomaterial consisting mainly of proteins in particular keratin. The structure of human hair is well known: the medulla is a loosely packed, disordered region near the centre of the hair surrounded by the cortex, which contains the major part of the fibre mass, mainly consisting of keratin proteins and structural lipids. The cortex is surrounded by the cuticle, a layer of dead, overlapping cells forming a protective layer around the hair. The corresponding structures have been studied extensively using a variety of different techniques, such as light, electron and atomic force microscopes, and also X-ray diffraction. We were interested in the question how much the molecular hair structure differs from person to person, between male and female hair, hair of different appearances such as colour and waviness. We included hair from parent and child, identical and fraternal twins in the study to see if genetically similar hair would show similar structural features. The molecular structure of the hair samples was studied using high-resolution X-ray diffraction, which covers length scales from molecules up to the organization of secondary structures. Signals due to the coiled-coil phase of α-helical keratin proteins, intermediate keratin filaments in the cortex and from the lipid layers in the cell membrane complex were observed in the specimen of all individuals, with very small deviations. Despite the relatively small number of individuals (12) included in this study, some conclusions can be drawn. While the general features were observed in all individuals and the corresponding molecular structures were almost identical, additional signals were observed in some specimen and assigned to different types of lipids in the cell membrane complex. Genetics seem to play a role in this composition as identical patterns were observed in hair from father and daughter and identical twins, however, not for fraternal twins. Identification and characterization

  3. Essentials of Hair Care often Neglected: Hair Cleansing.

    Science.gov (United States)

    Draelos, Zoe D

    2010-01-01

    Why does the selection of hair cleansing products and conditioners seem complex? Why are there clear, opalescent, green, blue, glittery, cheap, expensive, thick, thin, fragrant, and unscented varieties of shampoos and conditioners? Why the whole cleansing process cannot be simplified by using the same bar soap used on the body for the hair? Does the shampoo selected really make a difference? What can a conditioner accomplish?

  4. Determination of physicochemical properties of delipidized hair.

    Science.gov (United States)

    McMullen, Roger L; Laura, Donna; Chen, Susan; Koelmel, Donald; Zhang, Guojin; Gillece, Timothy

    2013-01-01

    Using various physicochemical methods of analysis, we examined human hair in its virgin and delipidized state. Free lipids were removed by a solvent extraction technique (covalently bound lipids were not removed) using a series of solvents with varying polarity. We analyzed the surface properties of hair by conducting mechanical combing and dynamic contact angle analysis. In addition, we used inverse gas chromatography surface energy analysis to explore the chemical composition of the hair surface based on interactions of various nonpolar and polar probes with biological molecules residing on the hair surface. Further, we investigated the importance that free lipids play in the internal structural properties of hair using dynamic scanning calorimetry and tensile strength measurements. The microstructure of the hair surface was probed by atomic force microscopy, whereas the lipid content of hair's morphological components was determined by infrared spectroscopic imaging. We also monitored the water management properties of virgin and delipidized hair by dynamic vapor sorption, which yielded unique water sorption isotherms for each hair type. Using all these techniques, differences were found in the chemical composition and physical behavior of virgin and delipidized hair. To better understand the influence of hair lipid composition on hair styling treatments, we conducted mechanical analyses of hair shaped into omega loops to determine the stiffness, elasticity, and flexibility of hair-polymer assemblies. Although there were no discernible differences between untreated virgin and delipidized hair, in terms of stiffness and elasticity, we found that treatment with hair styling agents produced different effects depending on the hair type used. Likewise, streaming potential measurements were carried out to monitor the binding capacity of rinse-off treatments on virgin and delipidized hair. Using this technique, we monitored the surface potential of hair and found

  5. Alterations in Hair Follicle Dynamics in Women

    OpenAIRE

    Claudine Piérard-Franchimont; Piérard, Gérald E.

    2013-01-01

    Endocrine changes supervening after parturition and menopause participate in the control of sebum production and hair growth modulation. The ensuing conditions include some peculiar aspects of hair loss (effluvium), alopecia, and facial hirsutism. The hair cycling is of major clinical relevance because most hair growth disorders result from disturbances in this chronobiological feature. Of note, any correlation between a biologic abnormality and hair cycling disturbance does not prove a relat...

  6. Effect of low-level laser treatment on cochlea hair-cell recovery after ototoxic hearing loss

    Science.gov (United States)

    Rhee, Chung-Ku; He, Peijie; Jung, Jae Yun; Ahn, Jin-Chul; Chung, Phil-Sang; Lee, Min Young; Suh, Myung-Whan

    2013-12-01

    The primary cause of hearing loss includes damage to cochlear hair cells. Low-level laser therapy (LLLT) has become a popular treatment for damaged nervous systems. Based on the idea that cochlea hair cells and neural cells are from same developmental origin, the effect of LLLT on hearing loss in animal models is evaluated. Hearing loss animal models were established, and the animals were irradiated by 830-nm diode laser once a day for 10 days. Power density of the laser treatment was 900 mW/cm2, and the fluence was 162 to 194 J. The tympanic membrane was evaluated after LLLT. Thresholds of auditory brainstem responses were evaluated before treatment, after gentamicin, and after 10 days of LLLT. Quantitative scanning electron microscopic (SEM) observations were done by counting remaining hair cells. Tympanic membranes were intact at the end of the experiment. No adverse tissue reaction was found. On SEM images, LLLT significantly increased the number of hair cells in middle and basal turns. Hearing was significantly improved by laser irradiation. After LLLT treatment, both the hearing threshold and hair-cell count significantly improved.

  7. Hair-Thread Tourniquet Syndrome

    Directory of Open Access Journals (Sweden)

    Emre Gokcen

    2016-01-01

    Two month-old male infant was brought to the emergency service with the complaint of fever, uneasiness, and swelling on 4th-5th toes of right foot.  Apparent swelling, rubescence and increase in heat were seen and a constrictive band was observed to surround proximal phalanges of both toes in the physical examination of the patient (Figure 1.  A hair was found on the constrictive band surrounding both toes. The hair was removed by means of forceps. Oral antibiotic was administered to the patient. The patient was treated successfully by not letting a necrosis develop on the toes. It should be remembered that hair-thread tourniquet syndrome may be observed in the infant patients applying to the hospital with the complaints of unexplained fever and uneasiness. Figure 1: Appearance of the toes right after the hair was removed. Arrows show the constrictive band. 

  8. Hair dryer burns in children.

    Science.gov (United States)

    Prescott, P R

    1990-11-01

    Three children with burn injuries caused by home hair dryers are described. In one patient the injury was believed to be accidental, and in the other two cases the injuries were deliberately caused by a caretaker. The lack of prior experience with hair dryer burns initially led to suspicion of other causes. The characteristics of each case aided in the final determination of accidental vs nonaccidental injury. These cases prompted testing of home hair dryers to determine their heat output. At the highest heat settings, the dryers rapidly generated temperatures in excess of 110 degrees C. After the dryers were turned off, the protective grills maintained sufficient temperatures to cause full-thickness burns for up to 2 minutes. These cases and the results of testing demonstrate that hair dryers must be added to the list of known causes of accidental and nonaccidental burns in children.

  9. Treatments for unwanted facial hair.

    Science.gov (United States)

    Shapiro, J; Lui, H

    Twenty-two percent of women in North America have unwanted facial hair, which can cause embarrassment and result in a significant emotional burden. Treatment options include plucking, waxing (including the sugar forms), depilatories, bleaching, shaving, electrolysis, laser, intense pulsed light (IPL), and eflornithine 13.9% cream (Vaniqa, Barrier Therapeutics in Canada and Shire Pharmaceuticals elsewhere). Eflornithine 13.9% cream is a topical treatment that does not remove the hairs, but acts to reduce the rate of growth and appears to be effective for unwanted facial hair on the mustache and chin area. Eflornithine 13.9% cream can be used in combination with other treatments such as lasers and IPL to give the patient the best chance for successful hair removal.

  10. Growing hairs in shorn cattle

    Directory of Open Access Journals (Sweden)

    Cecília José Veríssimo

    2013-12-01

    Full Text Available The shearing operation can provide double benefits to the cattle: they can become more heat tolerant and the tick infestation decreases. The cattle tick Rhipicephalus (Boophilus microplus causes great losses to dairy cattle, especially to the Holstein cattle because they are very susceptible to this tick. Its control is becoming each day more difficult, owing to the increasing resistance to acaricides they are acquiring. The objective of this work was to study the growing of haircoat following shearing. We made our experiment with 17 animals, 7 females and 10 males. They were shaved on the anterior third (head, neck, dewlap, scapula and arm of one side, at random. The work was performed in two steps: they were shorn for the first time on August 2nd 2012, with a size 10 blade in a clipper Oster model GoldenA5, which left the fur coat 2 mm long. Then we evaluated the hair length growing by collecting fortnightly three sample of hairs in the middle of the scapula, with  electric pliers, modified for this purpose, in both sides of the animals, sheared and non-sheared, until 30 days after this shearing. The three hair samples were put inside a little plastic bag per animal. Meanwhile, as we thought that the animals shearing had to be done closer to the skin, we decided to shear them again (in the same side shorn before, on October 2nd 2012. We changed our procedure using the same machine, but now with a blade size 30, which left the fur coat 1mm thick. After that, we collected again, fortnightly, samples of hairs on both sides during 2 months. The 10 longest hairs in the plastig bag were measured using a graph paper and the average per animal was calculated in each data and blade. A random design was applied for statistical analysis, the hair length of both sides, sheared and non sheared were compared by a two related samples tests – Wilcoxon, in a non parametric test, using the SPSSP 12.0 program, in each data within each blade. Using blade size

  11. Noise-induced cochlear F-actin depolymerization is mediated via ROCK2/p-ERM signaling.

    Science.gov (United States)

    Han, Yu; Wang, Xianren; Chen, Jun; Sha, Su-Hua

    2015-06-01

    Our previous work has suggested that traumatic noise activates Rho-GTPase pathways in cochlear outer hair cells (OHCs), resulting in cell death and noise-induced hearing loss (NIHL). In this study, we investigated Rho effectors, Rho-associated kinases (ROCKs), and the targets of ROCKs, the ezrin-radixin-moesin (ERM) proteins, in the regulation of the cochlear actin cytoskeleton using adult CBA/J mice under conditions of noise-induced temporary threshold shift (TTS) and permanent threshold shift (PTS) hearing loss, which result in changes to the F/G-actin ratio. The levels of cochlear ROCK2 and p-ERM decreased 1 h after either TTS- or PTS-noise exposure. In contrast, ROCK2 and p-ERM in OHCs decreased only after PTS-, not after TTS-noise exposure. Treatment with lysophosphatidic acid, an activator of the Rho pathway, resulted in significant reversal of the F/G-actin ratio changes caused by noise exposure and attenuated OHC death and NIHL. Conversely, the down-regulation of ROCK2 by pretreatment with ROCK2 siRNA reduced the expression of ROCK2 and p-ERM in OHCs, exacerbated TTS to PTS, and worsened OHC loss. Additionally, pretreatment with siRNA against radixin, an ERM protein, aggravated TTS to PTS. Our results indicate that a ROCK2-mediated ERM-phosphorylation signaling cascade modulates noise-induced hair cell loss and NIHL by targeting the cytoskeleton. We propose the following cascade following noise trauma leading to alteration of the F-actin arrangement in the outer hair cell cytoskeleton: Noise exposure reduces the levels of GTP-RhoA and subsequently diminishes levels of RhoA effector ROCK2 (Rho-associated kinase 2). Phosphorylation of ezrin-radixin-moesin (ERM) by ROCK2 normally allows ERM to cross-link actin filaments with the plasma membrane. Noise-decreased levels of ROCK results in reduction of phosphorylation of ERM that leads to depolymerization of actin filaments. Lysophosphatidic acid (LPA), an agonist of RhoA, binds to the G-protein-coupled receptor

  12. Trimethyltin-induced cochlear degeneration in rat

    Institute of Scientific and Technical Information of China (English)

    Jintao Yu; Dalian Ding; Hong Sun; Richard Salvi; Jerome A. Roth

    2016-01-01

    Trimethyltin (TMT) is an occupational and environmental health hazard behaving as a potent neurotoxin known to affect the central nervous system as well as the peripheral auditory system. However, the mechanisms underlying TMT-induced ototoxicity are poorly understood. To elucidate the effects of TMT on the cochlea, a single injection of 4 or 8 mg/kg TMT was administered intraperitoneally to adult rats. The compound action potential (CAP) threshold was used to assess the functional status of the cochlea and histological techniques were used to assess the condition of the hair cells and auditory nerve fibers. TMT at 4 mg/kg produced a temporary CAP threshold elevation of 25e60 dB that recovered by 28 d post-treatment. Although there was no hair cell loss with the 4 mg/kg dose, there was a noticeable loss of auditory nerve fibers particularly beneath the inner hair cells. TMT at 8 mg/kg produced a large permanent CAP threshold shift that was greatest at the high frequencies. The CAP threshold shift was associated with the loss of outer hair cells and inner hair cells in the basal, high-frequency region of the cochlea, considerable loss of auditory nerve fibers and a significant loss of spiral ganglion neurons in the basal turn. Spiral ganglion neurons showed evidence of soma shrinkage and nuclear condensation and fragmentation, morphological features of apoptotic cell death. TMT-induced damage was greatest in the high-frequency, basal region of the cochlea and the nerve fibers beneath the inner hair cells were the most vulnerable structures. Copyright © 2016, PLA General Hospital Department of Otolaryngology Head and Neck Surgery. Production and hosting by Elsevier (Singapore) Pte Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  13. A mutation in CABP2, expressed in cochlear hair cells, causes autosomal-recessive hearing impairment

    NARCIS (Netherlands)

    Schrauwen, I.; Helfmann, S.; Inagaki, A.; Predoehl, F.; Tabatabaiefar, M.A.; Picher, M.M.; Sommen, M.; Seco, C.Z.; Oostrik, J.; Kremer, J.M.J.; Dheedene, A.; Claes, C.; Fransen, E.; Chaleshtori, M.H.; Coucke, P.; Lee, A.; Moser, T.; Camp, G. van

    2012-01-01

    CaBPs are a family of Ca(2+)-binding proteins related to calmodulin and are localized in the brain and sensory organs, including the retina and cochlea. Although their physiological roles are not yet fully elucidated, CaBPs modulate Ca(2+) signaling through effectors such as voltage-gated Ca(v) Ca(2

  14. CSF gusher in cochlear implantation: The risk of missing CT evidence of a cochlear base defect in the presence of otherwise normal cochlear anatomy.

    Science.gov (United States)

    Cabbarzade, Cavid; Sennaroglu, Levent; Süslü, Nilda

    2015-07-01

    Intraoperative cerebrospinal fluid (CSF) leakages from the cochleostomy site - known as gushers - are a serious complication of cochlear implantation surgery in cases of congenital deafness. They occur as the result of abnormal communication between CSF in the internal auditory canal and perilymph in the cochlea. Gushers are well recognized as occurring in a proportion of cases in which there is a clearly visible congenital malformation of the cochlea. In this report, we describe two cases in which pre-operative computed tomography (CT) scanning of the cochlea was initially reported as normal but gushers occurred during cochlear implant surgery. In both cases, more detailed review of the CT scans (peroperatively in the first case, pre-operatively in the second case) showed a defect at the cochlear base, in the absence of any other cochlear malformation. The aim of this paper is to draw attention to the risk of missing this abnormality and to encourage careful inspection of the cochlear base on CT scans in all cases, even when the rest of the cochlear appears normal.

  15. Predicting chick body mass by artificial intelligence-based models

    Directory of Open Access Journals (Sweden)

    Patricia Ferreira Ponciano Ferraz

    2014-07-01

    Full Text Available The objective of this work was to develop, validate, and compare 190 artificial intelligence-based models for predicting the body mass of chicks from 2 to 21 days of age subjected to different duration and intensities of thermal challenge. The experiment was conducted inside four climate-controlled wind tunnels using 210 chicks. A database containing 840 datasets (from 2 to 21-day-old chicks - with the variables dry-bulb air temperature, duration of thermal stress (days, chick age (days, and the daily body mass of chicks - was used for network training, validation, and tests of models based on artificial neural networks (ANNs and neuro-fuzzy networks (NFNs. The ANNs were most accurate in predicting the body mass of chicks from 2 to 21 days of age after they were subjected to the input variables, and they showed an R² of 0.9993 and a standard error of 4.62 g. The ANNs enable the simulation of different scenarios, which can assist in managerial decision-making, and they can be embedded in the heating control systems.

  16. Racemic alkaloids from the fungus Ganoderma cochlear.

    Science.gov (United States)

    Wang, Xin-Long; Dou, Man; Luo, Qi; Cheng, Li-Zhi; Yan, Yong-Ming; Li, Rong-Tao; Cheng, Yong-Xian

    2017-01-01

    Seven pairs of new alkaloid enantiomers, ganocochlearines C-I (1, 3-8), and three pairs of known alkaloids were isolated from the fruiting bodies of Ganoderma cochlear. The chemical structures of new compounds were elucidated on the basis of 1D and 2D NMR data. The absolute configurations of compounds 1, 3-10 were assigned by ECD calculations. Biological activities of these isolates against renal fibrosis were accessed in rat normal or diseased renal interstitial fibroblast cells. Importantly, the plausible biosynthetic pathway for this class of alkaloids was originally proposed.

  17. Spatial channel interactions in cochlear implants

    Science.gov (United States)

    Tang, Qing; Benítez, Raul; Zeng, Fan-Gang

    2011-08-01

    The modern multi-channel cochlear implant is widely considered to be the most successful neural prosthesis owing to its ability to restore partial hearing to post-lingually deafened adults and to allow essentially normal language development in pre-lingually deafened children. However, the implant performance varies greatly in individuals and is still limited in background noise, tonal language understanding, and music perception. One main cause for the individual variability and the limited performance in cochlear implants is spatial channel interaction from the stimulating electrodes to the auditory nerve and brain. Here we systematically examined spatial channel interactions at the physical, physiological, and perceptual levels in the same five modern cochlear implant subjects. The physical interaction was examined using an electric field imaging technique, which measured the voltage distribution as a function of the electrode position in the cochlea in response to the stimulation of a single electrode. The physiological interaction was examined by recording electrically evoked compound action potentials as a function of the electrode position in response to the stimulation of the same single electrode position. The perceptual interactions were characterized by changes in detection threshold as well as loudness summation in response to in-phase or out-of-phase dual-electrode stimulation. To minimize potentially confounding effects of temporal factors on spatial channel interactions, stimulus rates were limited to 100 Hz or less in all measurements. Several quantitative channel interaction indexes were developed to define and compare the width, slope and symmetry of the spatial excitation patterns derived from these physical, physiological and perceptual measures. The electric field imaging data revealed a broad but uniformly asymmetrical intracochlear electric field pattern, with the apical side producing a wider half-width and shallower slope than the basal

  18. Integrating toxicity risk in bird eggs and chicks: Using chick down feathers to estimate mercury concentrations in eggs

    Science.gov (United States)

    Ackerman, Joshua T.; Eagles-Smith, Collin A.

    2009-01-01

    The concentration of mercury (Hg) in eggs that causes reduced hatching success is regarded as a critical end point for Hg toxicity in birds. However, incorporating effects of in ovo mercury exposure on chick health and survival could improve risk assessment. We developed equations to predict Hg in eggs using Hg in chick down feathers, and vice versa, by assessing the relationship between Hg in feathers (0.5−32.4 μg g−1 fw) and eggs (0.04−2.79 μg g−1 fww) for three waterbird species in San Francisco Bay, CA. Feather Hg sampled from embryos of pipping eggs was highly correlated with fresh whole-egg Hg (n = 94, r2 = 0.96). Additionally, using an egg microsampling technique, albumen Hg was correlated with feather Hg sampled from chicks in the same nest (n = 28, r2 = 0.79). Down feather Hg in recaptured chicks (≤10 days old) was correlated with down feather Hg at hatching (≤3 days old; n = 88, r2 = 0.74). Our results demonstrate the utility of using down feathers of chicks ≤10 days of age to nonlethally predict Hg in eggs and thus provide the ability to develop exposure thresholds for eggs that incorporate in ovo Hg’s effects on both egg hatchability and subsequent chick mortality.

  19. 6-Gingerol inhibits hair shaft growth in cultured human hair follicles and modulates hair growth in mice.

    Directory of Open Access Journals (Sweden)

    Yong Miao

    Full Text Available Ginger (Zingiber officinale has been traditionally used to check hair loss and stimulate hair growth in East Asia. Several companies produce shampoo containing an extract of ginger claimed to have anti-hair loss and hair growth promotion properties. However, there is no scientific evidence to back up these claims. This study was undertaken to measure 6-gingerol, the main active component of ginger, on hair shaft elongation in vitro and hair growth in vivo, and to investigate its effect on human dermal papilla cells (DPCs in vivo and in vitro. 6-Gingerol suppressed hair growth in hair follicles in culture and the proliferation of cultured DPCs. The growth inhibition of DPCs by 6-gingerol in vitro may reflect a decrease in the Bcl-2/Bax ratio. Similar results were obtained in vivo. The results of this study showed that 6-gingerol does not have the ability to promote hair growth, on the contrary, can suppress human hair growth via its inhibitory and pro-apoptotic effects on DPCs in vitro, and can cause prolongation of telogen phase in vivo. Thus, 6-gingerol rather than being a hair growth stimulating drug, it is a potential hair growth suppressive drug; i.e. for hair removal.

  20. Glycine immunoreactivity of multipolar neurons in the ventral cochlear nucleus which project to the dorsal cochlear nucleus.

    Science.gov (United States)

    Doucet, J R; Ross, A T; Gillespie, M B; Ryugo, D K

    1999-06-14

    Certain distinct populations of neurons in the dorsal cochlear nucleus are inhibited by a neural source that is responsive to a wide range of acoustic frequencies. In this study, we examined the glycine immunoreactivity of two types of ventral cochlear nucleus neurons (planar and radiate) in the rat which project to the dorsal cochlear nucleus (DCN) and thus, might be responsible for this inhibition. Previously, we proposed that planar neurons provided a tonotopic and narrowly tuned input to the DCN, whereas radiate neurons provided a broadly tuned input and thus, were strong candidates as the source of broadband inhibition (Doucet and Ryugo [1997] J. Comp. Neurol. 385:245-264). We tested this idea by combining retrograde labeling and glycine immunohistochemical protocols. Planar and radiate neurons were first retrogradely labeled by injecting biotinylated dextran amine into a restricted region of the dorsal cochlear nucleus. The labeled cells were visualized using streptavidin conjugated to indocarbocyanine (Cy3), a fluorescent marker. Sections that contained planar or radiate neurons were then processed for glycine immunocytochemistry using diaminobenzidine as the chromogen. Immunostaining of planar neurons was light, comparable to that of excitatory neurons (pyramidal neurons in the DCN), whereas immunostaining of radiate neurons was dark, comparable to that of glycinergic neurons (cartwheel cells in the dorsal cochlear nucleus and principal cells in the medial nucleus of the trapezoid body). These results are consistent with the hypothesis that radiate neurons in the ventral cochlear nucleus subserve the wideband inhibition observed in the dorsal cochlear nucleus.

  1. Hearing Preservation after Cochlear Implantation: UNICAMP Outcomes

    Directory of Open Access Journals (Sweden)

    Guilherme Machado de Carvalho

    2013-01-01

    Full Text Available Background. Electric-acoustic stimulation (EAS is an excellent choice for people with residual hearing in low frequencies but not high frequencies and who derive insufficient benefit from hearing aids. For EAS to be effective, subjects' residual hearing must be preserved during cochlear implant (CI surgery. Methods. We implanted 6 subjects with a CI. We used a special surgical technique and an electrode designed to be atraumatic. Subjects' rates of residual hearing preservation were measured 3 times postoperatively, lastly after at least a year of implant experience. Subjects' aided speech perception was tested pre- and postoperatively with a sentence test in quiet. Subjects' subjective responses assessed after a year of EAS or CI experience. Results. 4 subjects had total or partial residual hearing preservation; 2 subjects had total residual hearing loss. All subjects' hearing and speech perception benefited from cochlear implantation. CI diminished or eliminated tinnitus in all 4 subjects who had it preoperatively. 5 subjects reported great satisfaction with their new device. Conclusions. When we have more experience with our surgical technique we are confident we will be able to report increased rates of residual hearing preservation. Hopefully, our study will raise the profile of EAS in Brazil and Latin/South America.

  2. Stochastic beamforming for cochlear implant coding

    Science.gov (United States)

    Morse, Robert P.; Holmes, Stephen D.; Shulgin, Boris; Nikitin, Alexander; Stocks, Nigel G.

    2007-06-01

    Cochlear implants are prosthetic devices used to provide hearing to people who would otherwise be profoundly deaf. The deliberate addition of noise to the electrode signals could increase the amount of information transmitted, but standard cochlear implants do not replicate the noise characteristic of normal hearing because if noise is added in an uncontrolled manner with a limited number of electrodes then it will almost certainly lead to worse performance. Only if partially independent stochastic activity can be achieved in each nerve fibre can mechanisms like suprathreshold stochastic resonance be effective. We are investigating the use of stochastic beamforming to achieve greater independence. The strategy involves presenting each electrode with a linear combination of independent Gaussian noise sources. Because the cochlea is filled with conductive salt solutions, the noise currents from the electrodes interact and the effective stimulus for each nerve fibre will therefore be a different weighted sum of the noise sources. To some extent therefore, the effective stimulus for a nerve fibre will be independent of the effective stimulus of neighbouring fibres. For a particular patient, the electrode position and the amount of current spread are fixed. The objective is therefore to find the linear combination of noise sources that leads to the greatest independence between nerve discharges. In this theoretical study we show that it is possible to get one independent point of excitation (one null) for each electrode and that stochastic beamforming can greatly decrease the correlation between the noise exciting different regions of the cochlea.

  3. Determination of hair structure and shape.

    Science.gov (United States)

    Schlake, Thomas

    2007-04-01

    The hair follicle attracted significant attention as a model for the investigation of diverse biological problems. Whereas its morphology and the structure of the hair shaft are known in detail, the molecular biology of this miniorgan is significantly less characterised. Many efforts focussed on the development of the hair follicle and its stem cell reservoir; by contrast, the follicular product, the hair, which is interesting not only in terms of cosmetics was neglected. This review highlights our current knowledge of the control of hair structure and shape with emphasis on mouse hair follicle biology and discusses continuing problems.

  4. Repigmentation of hair following adalimumab therapy.

    Science.gov (United States)

    Tintle, Suzanne J; Dabade, Tushar S; Kalish, Robert A; Rosmarin, David M

    2015-06-16

    Repigmentation of canities, or age-related grey or white hair, is a rare occurrence. Generalized repigmentation of grey-white hair has been reported following inflammatory processes, and heterochromia (localized patches of hair repigmentation) is even more unusual, reported in association with medication use and malignancy. Tumor necrosis factor (TNF) inhibitors are increasingly utilized medications for inflammatory disorders, including psoriasis, rheumatoid arthritis, and inflammatory bowel disease. Hair loss, or alopecia, has been described among the side effects of these medications, but changes in hair pigmentation in association with this class of drugs have not previously been reported. We describe a patient with hair repigmentation associated with adalimumab therapy.

  5. Automatic hair detection in the wild

    DEFF Research Database (Denmark)

    Julian, Pauline; Dehais, Christophe; Lauze, Francois Bernard

    2010-01-01

    This paper presents an algorithm for segmenting the hair region in uncontrolled, real life conditions images. Our method is based on a simple statistical hair shape model representing the upper hair part. We detect this region by minimizing an energy which uses active shape and active contour....... The upper hair region then allows us to learn the hair appearance parameters (color and texture) for the image considered. Finally, those parameters drive a pixel-wise segmentation technique that yields the desired (complete) hair region. We demonstrate the applicability of our method on several real images....

  6. Nutrition and hair: deficiencies and supplements.

    Science.gov (United States)

    Finner, Andreas M

    2013-01-01

    Hair follicle cells have a high turnover. A caloric deprivation or deficiency of several components, such as proteins, minerals, essential fatty acids, and vitamins, caused by inborn errors or reduced uptake, can lead to structural abnormalities, pigmentation changes, or hair loss, although exact data are often lacking. The diagnosis is established through a careful history, clinical examination of hair loss activity, and hair quality and confirmed through targeted laboratory tests. Examples of genetic hair disorders caused by reduced nutritional components are zinc deficiency in acrodermatitis enteropathica and copper deficiency in Menkes kinky hair syndrome.

  7. Persistent Thalamic Sound Processing Despite Profound Cochlear Denervation

    Directory of Open Access Journals (Sweden)

    Anna R. Chambers

    2016-08-01

    Full Text Available Neurons at higher stages of sensory processing can partially compensate for a sudden drop in input from the periphery through a homeostatic plasticity process that increases the gain on weak afferent inputs. Even after a profound unilateral auditory neuropathy where > 95% of synapses between auditory nerve fibers and inner hair cells have been eliminated with ouabain, central gain can restore the cortical processing and perceptual detection of basic sounds delivered to the denervated ear. In this model of profound auditory neuropathy, cortical processing and perception recover despite the absence of an auditory brainstem response (ABR or brainstem acoustic reflexes, and only a partial recovery of sound processing at the level of the inferior colliculus (IC, an auditory midbrain nucleus. In this study, we induced a profound cochlear neuropathy with ouabain and asked whether central gain enabled a compensatory plasticity in the auditory thalamus comparable to the full recovery of function previously observed in the auditory cortex (ACtx, the partial recovery observed in the IC, or something different entirely. Unilateral ouabain treatment in adult mice effectively eliminated the ABR, yet robust sound-evoked activity persisted in a minority of units recorded from the contralateral medial geniculate body (MGB of awake mice. Sound-driven MGB units could decode moderate and high-intensity sounds with accuracies comparable to sham-treated control mice, but low-intensity classification was near chance. Pure tone receptive fields and synchronization to broadband pulse trains also persisted, albeit with significantly reduced quality and precision, respectively. MGB decoding of temporally modulated pulse trains and speech tokens were both greatly impaired in ouabain-treated mice. Taken together, the absence of an ABR belied a persistent auditory processing at the level of the MGB that was likely enabled through increased central gain. Compensatory

  8. Persistent Thalamic Sound Processing Despite Profound Cochlear Denervation

    Science.gov (United States)

    Chambers, Anna R.; Salazar, Juan J.; Polley, Daniel B.

    2016-01-01

    Neurons at higher stages of sensory processing can partially compensate for a sudden drop in peripheral input through a homeostatic plasticity process that increases the gain on weak afferent inputs. Even after a profound unilateral auditory neuropathy where >95% of afferent synapses between auditory nerve fibers and inner hair cells have been eliminated with ouabain, central gain can restore cortical processing and perceptual detection of basic sounds delivered to the denervated ear. In this model of profound auditory neuropathy, auditory cortex (ACtx) processing and perception recover despite the absence of an auditory brainstem response (ABR) or brainstem acoustic reflexes, and only a partial recovery of sound processing at the level of the inferior colliculus (IC), an auditory midbrain nucleus. In this study, we induced a profound cochlear neuropathy with ouabain and asked whether central gain enabled a compensatory plasticity in the auditory thalamus comparable to the full recovery of function previously observed in the ACtx, the partial recovery observed in the IC, or something different entirely. Unilateral ouabain treatment in adult mice effectively eliminated the ABR, yet robust sound-evoked activity persisted in a minority of units recorded from the contralateral medial geniculate body (MGB) of awake mice. Sound driven MGB units could decode moderate and high-intensity sounds with accuracies comparable to sham-treated control mice, but low-intensity classification was near chance. Pure tone receptive fields and synchronization to broadband pulse trains also persisted, albeit with significantly reduced quality and precision, respectively. MGB decoding of temporally modulated pulse trains and speech tokens were both greatly impaired in ouabain-treated mice. Taken together, the absence of an ABR belied a persistent auditory processing at the level of the MGB that was likely enabled through increased central gain. Compensatory plasticity at the level of the

  9. Restudy of malformations of the internal auditory meatus, cochlear nerve canal and cochlear nerve.

    Science.gov (United States)

    Li, Youjin; Yang, Jun; Liu, Jinfen; Wu, Hao

    2015-07-01

    The present study aims to restudy the correlation between the internal auditory meatus (IAM), the cochlear nerve canal (CNC), the cochlear nerve (CN) and inner ear malformations. In this retrospective study design, the abnormal diameter of the IAM, CNC and CN in patients with any kind of inner ear malformations was evaluated using multi-slice spiral computed tomography (MSCT) (37 patients) and magnetic resonance imaging (MRI) (18 patients). Of 37 MSCT-diagnosed patients, 2 had IAM atresia, 11 IAM stenosis, 22 enlarged IAM, and 2 normal IAM with an abnormal CN. MRI diagnoses of 18 patients revealed 8 cases of aplastic CN, 6 hypoplastic CN, and 4 normal CN. CNC stenosis was associated with CN hypoplasia (P malformations of the IAM, CNC and CN.

  10. Lexico-semantic and acoustic-phonetic processes in the perception of noise-vocoded speech: implications for cochlear implantation.

    Directory of Open Access Journals (Sweden)

    Carolyn eMcGettigan

    2014-02-01

    Full Text Available Noise-vocoding is a transformation which, when applied to speech, severely reduces spectral resolution and eliminates periodicity, yielding a stimulus that sounds like a harsh whisper (Scott, Blank et al. 2000. This process simulates a cochlear implant, where the activity of many thousand hair cells in the inner ear is replaced by direct stimulation of the auditory nerve by a small number of tonotopically-arranged electrodes. Although a cochlear implant offers a powerful means of restoring some degree of hearing to profoundly deaf individuals, the outcomes for spoken communication are highly variable (Moore and Shannon 2009. Some variability may arise from differences in peripheral representation (e.g. the degree of residual nerve survival but some may reflect differences in higher-order linguistic processing. In order to explore this possibility, we used noise-vocoding to explore speech recognition and perceptual learning in normal-hearing listeners tested across several levels of the linguistic hierarchy: segments (consonants and vowels, single words, and sentences. Listeners improved significantly on all tasks across two test sessions. In the first session, individual differences analyses revealed two independently varying sources of variability: one lexico-semantic in nature and implicating the recognition of words and sentences, and the other an acoustic-phonetic factor associated with words and segments. However, consequent to learning, by the second session there was a more uniform covariance pattern concerning all stimulus types. A further analysis of phonetic feature recognition allowed greater insight into learning-related changes in perception and showed that, surprisingly, participants did not make full use of cues that were preserved in the stimuli (e.g. vowel duration. We discuss these findings in relation cochlear implantation, and suggest auditory training strategies to maximise speech recognition performance in the absence of

  11. Axonal patterns and targets of dA1 interneurons in the chick hindbrain.

    Science.gov (United States)

    Kohl, Ayelet; Hadas, Yoav; Klar, Avihu; Sela-Donenfeld, Dalit

    2012-04-25

    Hindbrain dorsal interneurons that comprise the rhombic lip relay sensory information and coordinate motor outputs. The progenitor dA1 subgroup of interneurons, which is formed along the dorsal-most region of the caudal rhombic lip, gives rise to the cochlear and precerebellar nuclei. These centers project sensory inputs toward upper-brain regions. The fundamental role of dA1 interneurons in the assembly and function of these brainstem nuclei is well characterized. However, the precise en route axonal patterns and synaptic targets of dA1 interneurons are not clear as of yet. Novel genetic tools were used to label dA1 neurons and trace their axonal trajectories and synaptic connections at various stages of chick embryos. Using dA1-specific enhancers, two contralateral ascending axonal projection patterns were identified; one derived from rhombomeres 6-7 that elongated in the dorsal funiculus, while the other originated from rhombomeres 2-5 and extended in the lateral funiculus. Targets of dA1 axons were followed at later stages using PiggyBac-mediated DNA transposition. dA1 axons were found to project and form synapses in the auditory nuclei and cerebellum. Investigation of mechanisms that regulate the patterns of dA1 axons revealed a fundamental role of Lim-homeodomain (HD) proteins. Switch in the expression of the specific dA1 Lim-HD proteins Lhx2/9 into Lhx1, which is typically expressed in dB1 interneurons, modified dA1 axonal patterns to project along the routes of dB1 subgroup. Together, the results of this research provided new tools and knowledge to the assembly of trajectories and connectivity of hindbrain dA1 interneurons and of molecular mechanisms that control these patterns.

  12. Soft Hair on Black Holes.

    Science.gov (United States)

    Hawking, Stephen W; Perry, Malcolm J; Strominger, Andrew

    2016-06-10

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  13. Soft Hair on Black Holes

    CERN Document Server

    Hawking, Stephen W; Strominger, Andrew

    2016-01-01

    It has recently been shown that BMS supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft ($i.e.$ zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This paper gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the ho...

  14. Soft Hair on Black Holes

    Science.gov (United States)

    Hawking, Stephen W.; Perry, Malcolm J.; Strominger, Andrew

    2016-06-01

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  15. Hydrogen protects auditory hair cells from cisplatin-induced free radicals.

    Science.gov (United States)

    Kikkawa, Yayoi S; Nakagawa, Takayuki; Taniguchi, Mirei; Ito, Juichi

    2014-09-05

    Cisplatin is a widely used chemotherapeutic agent for the treatment of various malignancies. However, its maximum dose is often limited by severe ototoxicity. Cisplatin ototoxicity may require the production of reactive oxygen species (ROS) in the inner ear by activating enzymes specific to the cochlea. Molecular hydrogen was recently established as an antioxidant that selectively reduces ROS, and has been reported to protect the central nervous system, liver, kidney and cochlea from oxidative stress. The purpose of this study was to evaluate the potential of molecular hydrogen to protect cochleae against cisplatin. We cultured mouse cochlear explants in medium containing various concentrations of cisplatin and examined the effects of hydrogen gas dissolved directly into the media. Following 48-h incubation, the presence of intact auditory hair cells was assayed by phalloidin staining. Cisplatin caused hair cell loss in a dose-dependent manner, whereas the addition of hydrogen gas significantly increased the numbers of remaining auditory hair cells. Additionally, hydroxyphenyl fluorescein (HPF) staining of the spiral ganglion showed that formation of hydroxyl radicals was successfully reduced in hydrogen-treated cochleae. These data suggest that molecular hydrogen can protect auditory tissues against cisplatin toxicity, thus providing an additional strategy to protect against drug-induced inner ear damage.

  16. Language understanding and vocabulary of early cochlear implanted children

    DEFF Research Database (Denmark)

    Percy-Smith, Lone; Busch, Georg Walter; Sandahl, Minna;

    2013-01-01

    The aim of the study was to identify factors associated with the level of language understanding, the level of receptive and active vocabulary, and to estimate effect-related odds ratios for cochlear implanted children's language level....

  17. Audiological findings from an adult with thin cochlear nerves

    Science.gov (United States)

    Prabhu, Prashanth; Shivaswamy, Jyothi

    2017-01-01

    Summary Reported here are audiological findings from an adult with thin cochlear nerves. Magnetic resonance imaging (MRI) revealed that he had a thinner cochlear nerve in the left ear than in the right ear. He had a higher degree of hearing loss in the left ear and poor speech recognition scores for both ears. He had normal middle ear and cochlear functioning. The auditory brainstem response and acoustic reflexes were absent, indicating a retrocochlear pathology. Long latency responses (LLR) revealed normal cortical functioning. Hence, implantation of an auditory brainstem implant might be an option, but the patient would need to be aware of its limitations. This case highlights the importance of MRI in evaluating congenital malformations of the cochlear nerve when audiological findings indicate a retrocochlear pathology. PMID:28357188

  18. Cochlear implant outcomes in patients with superior canal dehiscence

    NARCIS (Netherlands)

    Puram, Sidharth V.; Roberts, Daniel S.; Niesten, Marlien E F; Dilger, Amanda E.; Lee, Daniel J.

    2015-01-01

    Objective: To determine whether adult cochlear implant (CI) users with superior canal dehiscence syndrome (SCDS) or asymptomatic superior semicircular canal dehiscence (SCD) have different surgical, vestibular, and audiologic outcomes when compared to CI users with normal temporal bone anatomy. Meth

  19. Sound localization ability of young children with bilateral cochlear implants.

    NARCIS (Netherlands)

    Beijen, J.W.; Snik, A.F.M.; Mylanus, E.A.M.

    2007-01-01

    OBJECTIVE: To evaluate the benefit of bilateral cochlear implantation in young children. STUDY DESIGN: Clinical trial comparing a group of bilaterally implanted children with a group of unilaterally implanted children. SETTING: Tertiary referral center. PATIENTS: Five bilaterally implanted children

  20. [Advances in the study of virtual channels of cochlear implant].

    Science.gov (United States)

    Zhu, Ziyan; Guan, Tian; Ye, Datian

    2009-12-01

    This paper discusses virtual channels of cochlear implant, which is produced by simultaneous or sequential activation of adjacent cochlear implant electrodes. Virtual channels create and transfer more available spectral pitch information with the limited number of fixed electrodes, which can be recognized as pitch percepts intermediate to those produced by each electrode separately. This technique not only utilizes the interaction of electrodes but also increases the number of place-pitch steps available to cochlear implant listeners. Virtual channels could be used to realize speech recognition in noisy environment, in enjoying music, and in understanding Chinese language. The study of virtual channels would significantly enhance the traditional cochlear implant therapy and benefit people suffering severe to profound hearing loss.

  1. Studying the Language Development in Children with Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Marjan Sabri leghaie

    1996-04-01

    Full Text Available Cochlear implant surgery is aimed at making a comprehensive packet of information for the deaf by mixing the data acquired by implanted device and the communicational grammar. Although language production and ability of communication are not main factors in determining the candidacy for cochlear implant surgery, they play crucial role in determining cochlear implant success. we should study the communication skills much deeper than a simple perception and production of speech to have a reasonable evaluation of development of Auditory integration and grammatical language structure. Hence in the current article we will first discuss the grammatical structure in language and then have a look at the pragmatics , semantics and phonological aspects in children with cochlear implant in Virginia college in USA.

  2. Phase of shear vibrations within cochlear partition leads to activation of the cochlear amplifier.

    Directory of Open Access Journals (Sweden)

    Jessica S Lamb

    Full Text Available Since Georg von Bekesy laid out the place theory of the hearing, researchers have been working to understand the remarkable properties of mammalian hearing. Because access to the cochlea is restricted in live animals, and important aspects of hearing are destroyed in dead ones, models play a key role in interpreting local measurements. Wentzel-Kramers-Brillouin (WKB models are attractive because they are analytically tractable, appropriate to the oblong geometry of the cochlea, and can predict wave behavior over a large span of the cochlea. Interest in the role the tectorial membrane (TM plays in cochlear tuning led us to develop models that directly interface the TM with the cochlear fluid. In this work we add an angled shear between the TM and reticular lamina (RL, which serves as an input to a nonlinear active force. This feature plus a novel combination of previous work gives us a model with TM-fluid interaction, TM-RL shear, a nonlinear active force and a second wave mode. The behavior we get leads to the conclusion the phase between the shear and basilar membrane (BM vibration is critical for amplification. We show there is a transition in this phase that occurs at a frequency below the cutoff, which is strongly influenced by TM stiffness. We describe this mechanism of sharpened BM velocity profile, which demonstrates the importance of the TM in overall cochlear tuning and offers an explanation for the response characteristics of the Tectb mutant mouse.

  3. The effect of hair bundle shape on hair bundle hydrodynamics of inner ear hair cells at low and high frequencies.

    Science.gov (United States)

    Shatz, L F

    2000-03-01

    The relationship between size and shape of the hair bundle of a hair cell in the inner ear and its sensitivity at asymptotically high and low frequencies was determined, thereby extending the results of an analysis of hair bundle hydrodynamics in two dimensions (Freeman and Weiss, 1990. Hydrodynamic analysis of a two-dimensional model for micromechanical resonance of free-standing hair bundles. Hear. Res. 48, 37-68) to three dimensions. A hemispheroid was used to represent the hair bundle. The hemispheroid had a number of advantages: it could represent shapes that range from thin, pencil-like shapes, to wide, flat, disk-like shapes. Also analytic methods could be used in the high frequency range to obtain an exact solution to the equations of motion. In the low frequency range, where an approximate solution was found using boundary element methods, the sensitivity of the responses of hair cells was mainly proportional to the cube of the heights of their hair bundles, and at high frequencies, the sensitivity of the hair cells was mainly proportional to the inverse of their heights. An excellent match was obtained between measurements of sensitivity curves in the basillar papilla of the alligator and bobtail lizards and the model's predictions. These results also suggest why hair bundles of hair cells in vestibular organs which are sensitive to low frequencies have ranges of heights that are an order of magnitude larger than the range of heights of hair bundles of hair cells found in auditory organs.

  4. 'Uncombable' Hair? Maybe Genes Are to Blame

    Science.gov (United States)

    ... gov/news/fullstory_162727.html 'Uncombable' Hair? Maybe Genes Are to Blame Condition is rare, tends to ... combed normally. Now researchers say they've found genes linked to what's known as "uncombable hair syndrome." " ...

  5. "COCHLEAR IMPLANTATION IN PATIENTS WITH INNER EAR MALFORMATIONS"

    OpenAIRE

    P. Borghei S. Abdi; M. Motesaddi Zari; Khalessi MH

    2004-01-01

    Performing cochlear implantation in patients with inner ear malformation has always been a matter of dispute. This study was designed to analyze the operative findings,complications, and postoperative performance of patients with inner ear anomalies who underwent cochlear implantation. Six patients with inner ear malformations underwent implantation in our academic tertiary referral center from 1997 to 2002. The average follow-up period was 27 months. Malformations included one incomplete par...

  6. Cochlear abnormality in a case of Pallister-Hall syndrome.

    Science.gov (United States)

    Avula, Shivaram; Alam, Nusrat; Roberts, Elaine

    2012-12-01

    Pallister-Hall syndrome (PHS) is a rare condition characterised by anomalies including hypothalamic hamartoma, bifid epiglottis and postaxial polydactyly. Hearing loss has been recognised in this condition. Cochlear abnormalities have been described in mouse models of PHS, but there are no reports of similar findings in humans to date. This report describes a case of PHS with bilateral cochlear hypoplasia as seen on MRI.

  7. Facial nerve stimulation after cochlear implantation: our experience

    OpenAIRE

    BERRETTINI, S.; De Vito, A.; Bruschini, L.; PASSETTI, S.; Forli, F.

    2011-01-01

    SUMMARY Post-implantation facial nerve stimulation is one of the best known and most frequent complications of the cochlear implant procedure. Some conditions, such as otosclerosis and cochlear malformations, as well as high stimulation levels that may be necessary in patients with long auditory deprivation, expose patients to a higher risk of developing post-implant facial nerve stimulation. Facial nerve stimulation can frequently be resolved with minimal changes in speech processor fitting ...

  8. Nuclear entry of hyperbranched polylysine nanoparticles into cochlear cells

    Directory of Open Access Journals (Sweden)

    Weikai Zhang

    2011-03-01

    Full Text Available Weikai Zhang1, Ya Zhang1, Marian Löbler2, Klaus-Peter Schmitz2, Aqeel Ahmad3, Ilmari Pyykkö1, Jing Zou11Department of Otolaryngology, University of Tampere, Medical School, Tampere, Finland; 2University of Rostock, Institute for Biomedical Engineering, Rostock, Germany; 3Department of Biomedical Engineering and Computational Science, Aalto University, Espoo, FinlandBackground: Gene therapy is a potentially effective therapeutic modality for treating sensorineural hearing loss. Nonviral gene delivery vectors are expected to become extremely safe and convenient, and nanoparticles are the most promising types of vectors. However, infrequent nuclear localization in the cochlear cells limits their application for gene therapy. This study aimed to investigate the potential nuclear entry of hyperbranched polylysine nanoparticles (HPNPs for gene delivery to cochlear targets.Methods: Rat primary cochlear cells and cochlear explants generated from newborn rats were treated with different concentrations of HPNPs. For the in vivo study, HPNPs were administered to the rats' round window membranes. Subcellular distribution of HPNPs in different cell populations was observed with confocal microscope 24 hours after administration.Results: Nuclear entry was observed in various cochlear cell types in vitro and in vivo. In the primary cochlear cell culture, concentration-dependent internalization was observed. In the cochlear organotypic culture, abundant HPNPs were found in the modiolus, including the spiral ganglion, organ of Corti, and lateral wall tissues. In the in vivo study, a gradient distribution of HPNPs through different layers of the round window membrane was observed. HPNPs were also distributed in the cells of the middle ear tissue. Additionally, efficient internalization of HPNPs was observed in the organ of Corti and spiral ganglion cells. In primary cochlear cells, HPNPs induced higher transfection efficiency than did Lipofectamine

  9. Abnormal pitch perception produced by cochlear implant stimulation.

    Directory of Open Access Journals (Sweden)

    Fan-Gang Zeng

    Full Text Available Contemporary cochlear implants with multiple electrode stimulation can produce good speech perception but poor music perception. Hindered by the lack of a gold standard to quantify electric pitch, relatively little is known about the nature and extent of the electric pitch abnormalities and their impact on cochlear implant performance. Here we overcame this obstacle by comparing acoustic and electric pitch perception in 3 unilateral cochlear-implant subjects who had functionally usable acoustic hearing throughout the audiometric frequency range in the non-implant ear. First, to establish a baseline, we measured and found slightly impaired pure tone frequency discrimination and nearly perfect melody recognition in all 3 subjects' acoustic ear. Second, using pure tones in the acoustic ear to match electric pitch induced by an intra-cochlear electrode, we found that the frequency-electrode function was not only 1-2 octaves lower, but also 2 times more compressed in frequency range than the normal cochlear frequency-place function. Third, we derived frequency difference limens in electric pitch and found that the equivalent electric frequency discrimination was 24 times worse than normal-hearing controls. These 3 abnormalities are likely a result of a combination of broad electric field, distant intra-cochlear electrode placement, and non-uniform spiral ganglion cell distribution and survival, all of which are inherent to the electrode-nerve interface in contemporary cochlear implants. Previous studies emphasized on the "mean" shape of the frequency-electrode function, but the present study indicates that the large "variance" of this function, reflecting poor electric pitch discriminability, is the main factor limiting contemporary cochlear implant performance.

  10. Parallel mechanisms suppress cochlear bone remodeling to protect hearing.

    Science.gov (United States)

    Jáuregui, Emmanuel J; Akil, Omar; Acevedo, Claire; Hall-Glenn, Faith; Tsai, Betty S; Bale, Hrishikesh A; Liebenberg, Ellen; Humphrey, Mary Beth; Ritchie, Robert O; Lustig, Lawrence R; Alliston, Tamara

    2016-08-01

    Bone remodeling, a combination of bone resorption and formation, requires precise regulation of cellular and molecular signaling to maintain proper bone quality. Whereas osteoblasts deposit and osteoclasts resorb bone matrix, osteocytes both dynamically resorb and replace perilacunar bone matrix. Osteocytes secrete proteases like matrix metalloproteinase-13 (MMP13) to maintain the material quality of bone matrix through perilacunar remodeling (PLR). Deregulated bone remodeling impairs bone quality and can compromise hearing since the auditory transduction mechanism is within bone. Understanding the mechanisms regulating cochlear bone provides unique ways to assess bone quality independent of other aspects that contribute to bone mechanical behavior. Cochlear bone is singular in its regulation of remodeling by expressing high levels of osteoprotegerin. Since cochlear bone expresses a key PLR enzyme, MMP13, we examined whether cochlear bone relies on, or is protected from, osteocyte-mediated PLR to maintain hearing and bone quality using a mouse model lacking MMP13 (MMP13(-/-)). We investigated the canalicular network, collagen organization, lacunar volume via micro-computed tomography, and dynamic histomorphometry. Despite finding defects in these hallmarks of PLR in MMP13(-/-) long bones, cochlear bone revealed no differences in these markers, nor hearing loss as measured by auditory brainstem response (ABR) or distortion product oto-acoustic emissions (DPOAEs), between wild type and MMP13(-/-) mice. Dynamic histomorphometry revealed abundant PLR by tibial osteocytes, but near absence in cochlear bone. Cochlear suppression of PLR corresponds to repression of several key PLR genes in the cochlea relative to long bones. These data suggest that cochlear bone uniquely maintains bone quality and hearing independent of MMP13-mediated osteocytic PLR. Furthermore, the cochlea employs parallel mechanisms to inhibit remodeling by osteoclasts and osteoblasts, and by

  11. Hypoxia adaptation and hemoglobin mutation in Tibetan chick embryo

    Institute of Scientific and Technical Information of China (English)

    GOU Xiao; LI Ning; LIAN Linsheng; YAN Dawei; ZHANG Hao; WU Changxin

    2005-01-01

    Tibetan chick lives at high altitudes between 2600 and 4200 m with a high hatchability and low land breeds survive rarely with a hatchability of 3.0% under hypoxia of simulated 4200 m. Under hypoxia of whole 21 d, the hatchability of Tibetan chick and Recessive White Feather broiler differed with a greatest disparity from day 4 to 11 and also significantly in other stages except from day 1 to 3. Hypoxia in each stage did not reduce significantly survival rate of this stage except hatchability. These two results indicated that the hypoxia in the early stage had an adverse effect on the later stage. All exons encoding chick hemoglobins were sequenced to analyze gene polymorphism. The functional mutation Met-32(B13)-Leu, related with hypoxia, was found in αD globin chain and the mutation frequency increased with increased altitude. In addition, under hypoxic conditions, the population with higher mutation frequency had a higher hatchability. The automated homology model building was carried out using crystal structure coordinates of chick HbD. The results indicated that the substitution Met-32(B13)-Leu provides a more hydrophobic environment which leads to higher stability of heme and oxygen affinity of hemoglobin. The occurrence of the mutation Met-32(B13)-Leu is related to the origin of Tibetan chick.

  12. Cognitive bias in the chick anxiety-depression model.

    Science.gov (United States)

    Salmeto, Amy L; Hymel, Kristen A; Carpenter, Erika C; Brilot, Ben O; Bateson, Melissa; Sufka, Kenneth J

    2011-02-10

    Cognitive bias is a phenomenon that presents in clinical populations where anxious individuals tend to adopt a more pessimistic-like interpretation of ambiguous aversive stimuli whereas depressed individuals tend to adopt a less optimistic-like interpretation of ambiguous appetitive stimuli. To further validate the chick anxiety-depression model as a neuropsychiatric simulation we sought to quantify this cognitive endophenotype. Chicks exposed to an isolation stressor of 5m to induce an anxiety-like or 60 m to induce a depressive-like state were then tested in a straight alley maze to a series of morphed ambiguous appetitive (chick silhouette) to aversive (owl silhouette) cues. In non-isolated controls, runway start and goal latencies generally increased as a function of greater amounts of aversive characteristics in the cues. In chicks in the anxiety-like state, runway latencies were increased to aversive ambiguous cues, reflecting more pessimistic-like behavior. In chicks in the depression-like state, runway latencies were increased to both aversive and appetitive ambiguous cues, reflecting more pessimistic-like and less optimistic-like behavior, respectively.

  13. Hair transplantation in alopecia androgenetica

    Directory of Open Access Journals (Sweden)

    Singh Gurinderjit

    1992-01-01

    Full Text Available One hundred patients suffering from male pattern baldness were given 3 to 4 sittings of hair transplantation at an interval of about 4 to 6 weeks each. They included 46 patients of type III baldness, 23 patients of type III (vertex baldness, and 31 patients of type IV baldness. It needed 3 sittings in type III as well as type III (vertex patients, whereas type IV patients needed 4 sittings for cosmetically acceptable results. Sixty percent patients of type III (including type III vertex showed excellent results; whereas 24 percent patients showed good response. Thirty-four percent patients of type IV got excellent cosmetic appearance; whereas, good results could be obtained in 17 percent patients. The reasons for poor results in certain patients were poor density of hair at donor sites and poor growth of hair in some of the transplanted plugs.

  14. Ethnic hair care products may increase false positives in hair drug testing.

    Science.gov (United States)

    Kidwell, David A; Smith, Frederick P; Shepherd, Arica R

    2015-12-01

    The question of why different races appear more susceptible to hair contamination by external drugs remains controversial. This research studied susceptibility of head hair to external cocaine and methamphetamine when hair products have been applied. Three different chemical classes of ethnic hair products were applied to Caucasian, Asian, and African hair. Some products increased the methamphetamine and cocaine concentrations in all hair types. A unique finding of this research is that certain ethnic hair products can replace moisture as a diffusion medium, thereby increasing the susceptibility to contamination over 100-fold compared to petroleum-based products.

  15. Intermediate frequency magnetic field and chick embryotoxicity.

    Science.gov (United States)

    Nishimura, Izumi; Tanaka, Keiko; Negishi, Tadashi

    2013-09-01

    Intermediate frequency magnetic fields (MFs) have widely been used in industrial machines and home appliances, such as induction heating cookers, although toxicity studies to evaluate the potential health risks of such fields are insufficient. In induction heating cookers, the MF source (i.e. hobs), is located near the abdominal position of a person cooking. Hence, developmental effects on the fetus may be a concern in case the person is a pregnant woman. Fertile White Leghorn eggs (60/group) were either exposed to 20 kHz, 1.1 mT(rms) or 60 kHz, 0.11 mT(rms) sinusoidal MFs for 19 days during embryogenesis. The same number of eggs served as a control group. In addition, a sham-sham experiment was conducted to validate the equality between exposure and control facilities. After exposure, embryos were examined for mortality rate and stage. Live embryos were evaluated for developmental stage and gross and skeletal anomalies. Length of upper beak and leg digits was also measured. Examinations were conducted in a blinded fashion to ensure quality assurance; experiments were triplicated for each frequency to confirm the outcome reproducibility. Mortality rate and stage, incidence of malformed embryos, and developmental variables in live embryos were found to be similar between the MF-exposed and corresponding control group. Incidence of gross anomalies such as mandibular edema and skeletal anomalies such as coccyx defects were low across the experiments, and no significant group differences were noted. In conclusion, exposure to 20 kHz or 60 kHz MF did not produce any significant teratogenic developmental effects in chick embryos.

  16. Quantitative polarized light microscopy of unstained mammalian cochlear sections

    Science.gov (United States)

    Kalwani, Neil M.; Ong, Cheng Ai; Lysaght, Andrew C.; Haward, Simon J.; McKinley, Gareth H.; Stankovic, Konstantina M.

    2013-02-01

    Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarized light microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo.

  17. Immunohistochemical study of hair follicle stem cells in regenerated hair follicles induced by Wnt10b

    Science.gov (United States)

    Zhang, Yiming; Xing, Yizhan; Guo, Haiying; Ma, Xiaogen; Li, Yuhong

    2016-01-01

    The regulation of the periodic regeneration of hair follicles is complicated. Although Wnt10b has been reported to induce hair follicle regeneration, the characteristics of induced hair follicles, especially the target cells of Wnt10b, have not yet been clearly elucidated. Thus, we systematically evaluated the expression and proliferation patterns of Wnt10b-induced hair follicles. We found that Wnt10b promoted the proliferation of hair follicle stem cells from 24 hours after AdWnt10b injection. Seventy-two hours after AdWnt10b injection, cells outside of bulge area began to proliferate. When the induced hair follicle entered full anagen, although the hair follicle stem cells were normal, canonical Wnt signaling was maintained in the hair precortex cells. Our results reveal that the target cells that overexpressed Wnt10b included hair follicle stem cells, hair precortex cells, and matrix cells.

  18. ``Dissection'' of a Hair Dryer

    Science.gov (United States)

    Eisenstein, Stan; Simpson, Jeff

    2008-12-01

    The electrical design of the common hair dryer is based almost entirely on relatively simple principles learned in introductory physics classes. Just as biology students dissect a frog to see the principles of anatomy in action, physics students can "dissect" a hair dryer to see how principles of electricity are used in a real system. They can discover how engineers solve problems such as how to vary between low and high heat and fan speed by simply moving the position of a single switch. Principles of alternating versus direct current, series and parallel circuits, electrical safety, voltage dividing, ac rectification, power, and measurement of resistance and continuity all come in to play.

  19. Natural remedies in hair care and treatment

    OpenAIRE

    Ercan Karabacak; Bilal Doğan

    2014-01-01

    For thousands of years, people benefited from natural products to have healthy hair. Nowadays this one of complementary and alternative medicine methods are preferred as an increasing frequency. Natural products used in hair care may vary by geographic region and ethnic origin. In this review, natural products used in hair care and diseases were studied.

  20. Natural remedies in hair care and treatment

    Directory of Open Access Journals (Sweden)

    Ercan Karabacak

    2014-06-01

    Full Text Available For thousands of years, people benefited from natural products to have healthy hair. Nowadays this one of complementary and alternative medicine methods are preferred as an increasing frequency. Natural products used in hair care may vary by geographic region and ethnic origin. In this review, natural products used in hair care and diseases were studied.

  1. Ultra-Wideband Transceivers for Cochlear Implants

    Directory of Open Access Journals (Sweden)

    Reisenzahn Alexander

    2005-01-01

    Full Text Available Ultra-wideband (UWB radio offers low power consumption, low power spectral density, high immunity against interference, and other benefits, not only for consumer electronics, but also for medical devices. A cochlear implant (CI is an electronic hearing apparatus, requiring a wireless link through human tissue. In this paper we propose an UWB link for a data rate of Mbps and a propagation distance up to 500 mm. Transmitters with step recovery diode and transistor pulse generators are proposed. Two types of antennas and their filter characteristics in the UWB spectrum will be discussed. An ultra-low-power back tunnel diode receiver prototype is described and compared with conventional detector receivers.

  2. Deafness in cochlear and auditory nerve disorders.

    Science.gov (United States)

    Hopkins, Kathryn

    2015-01-01

    Sensorineural hearing loss is the most common type of hearing impairment worldwide. It arises as a consequence of damage to the cochlea or auditory nerve, and several structures are often affected simultaneously. There are many causes, including genetic mutations affecting the structures of the inner ear, and environmental insults such as noise, ototoxic substances, and hypoxia. The prevalence increases dramatically with age. Clinical diagnosis is most commonly accomplished by measuring detection thresholds and comparing these to normative values to determine the degree of hearing loss. In addition to causing insensitivity to weak sounds, sensorineural hearing loss has a number of adverse perceptual consequences, including loudness recruitment, poor perception of pitch and auditory space, and difficulty understanding speech, particularly in the presence of background noise. The condition is usually incurable; treatment focuses on restoring the audibility of sounds made inaudible by hearing loss using either hearing aids or cochlear implants.

  3. Phase contrast imaging of cochlear soft tissue.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.; Hwang, M.; Rau, C.; Fishman, A.; Lee, W.; Richter, C. (X-Ray Science Division); (Northwestern Univ.); (Diamond Light Source, Ltd.)

    2011-01-01

    A noninvasive technique to image soft tissue could expedite diagnosis and disease management in the auditory system. We propose inline phase contrast imaging with hard X-rays as a novel method that overcomes the limitations of conventional absorption radiography for imaging soft tissue. In this study, phase contrast imaging of mouse cochleae was performed at the Argonne National Laboratory Advanced Photon Source. The phase contrast tomographic reconstructions show soft tissue structures of the cochlea, including the inner pillar cells, the inner spiral sulcus, the tectorial membrane, the basilar membrane, and the Reissner's membrane. The results suggest that phase contrast X-ray imaging and tomographic techniques hold promise to noninvasively image cochlear structures at an unprecedented cellular level.

  4. Accurate guitar tuning by cochlear implant musicians.

    Directory of Open Access Journals (Sweden)

    Thomas Lu

    Full Text Available Modern cochlear implant (CI users understand speech but find difficulty in music appreciation due to poor pitch perception. Still, some deaf musicians continue to perform with their CI. Here we show unexpected results that CI musicians can reliably tune a guitar by CI alone and, under controlled conditions, match simultaneously presented tones to <0.5 Hz. One subject had normal contralateral hearing and produced more accurate tuning with CI than his normal ear. To understand these counterintuitive findings, we presented tones sequentially and found that tuning error was larger at ∼ 30 Hz for both subjects. A third subject, a non-musician CI user with normal contralateral hearing, showed similar trends in performance between CI and normal hearing ears but with less precision. This difference, along with electric analysis, showed that accurate tuning was achieved by listening to beats rather than discriminating pitch, effectively turning a spectral task into a temporal discrimination task.

  5. Prevention of Noise Damage to Cochlear Synapses

    Science.gov (United States)

    2015-10-01

    antibody blocking buffer 5% horse serum / 0.1% bovine serum albumin / 0.1% Triton / 0.02% NaN3 for 60 min at room temperature. Immunostaining: The hair...the possibility that osmotic stress is responsible in part for excitotoxic damage to synapses. Alternatively, it may be that the in vitro excitotoxic... stress is exceptionally strong and is not an accurate model of noise exposure in vivo. Methodology Using neonatal (postnatal day 5, P5) rat

  6. Changes in free amino acid and monoamine concentrations in the chick brain associated with feeding behavior

    OpenAIRE

    Tran, Phuong V; Chowdhury, Vishwajit S.; Nagasawa, Mao; Furuse, Mitsuhiro

    2015-01-01

    Domesticated chicks are precocial and therefore have relatively well-developed feeding behavior. The role of hypothalamic neuropeptides in food-intake regulation in chicks has been reported for decades. However, we hypothesized that nutrients and their metabolites in the brain may be involved in food intake in chicks because these animals exhibit a very frequent feeding pattern. Therefore, the purpose of this study was to examine the feeding behavior of chicks as well as the associated change...

  7. Hair cell specific NTPDase6 immunolocalisation in vestibular end organs: potential role of purinergic signaling in vestibular sensory transduction.

    Science.gov (United States)

    O'Keeffe, Mary G; Thorne, Peter R; Housley, Gary D; Robson, Simon C; Vlajkovic, Srdjan M

    2012-01-01

    A complex extracellular nucleotide signalling system acting on P2 receptors is involved in regulation of cochlear function in the mammalian inner ear. Ectonucleoside triphosphate diphosphohydrolases (E-NTPDases) are ectonucleotidases that regulate P2 receptor signalling pathways in mammalian tissues by hydrolysing extracellular nucleotides to the respective nucleosides. All enzymes from the CD39/ENTPD family (NTPDase1-8) are expressed in the adult rat cochlea, but their expression and distribution in the vestibular end organ is unknown. This report demonstrates selective expression of NTPDase6 by rat vestibular hair cells. Hair cells transducing both angular acceleration (crista ampullaris) and static head position (maculae of the utricle and saccule) exhibited strong immunolabelling with a bias towards the sensory pole and in particular, the hair cell bundle. NTPDase6 is an intracellular enzyme that can be released in a soluble form from cell cultures and shows an enzymatic preference for nucleoside 5'-diphosphates, such as guanosine 5'-diphosphate (GDP) and uridine 5'-diphosphate (UDP). The main function of NTPDase6 may be the regulation of nucleotide levels in cellular organelles by regulating the conversion of nucleotides to nucleosides. NTPDase6 immunolocalisation in the vestibular end organ could be linked to the regulation of P2 receptor signalling and sensory transduction, including maintenance of vestibular hair bundles.

  8. The cochlear nerve canal and internal auditory canal in children with normal cochlea but cochlear nerve deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Fei; Li, Jianhong; Xian, Junfang; Wang, Zhenchang [Dept. of Radiology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)], e-mail: cjr.wzhch@vip.163.com; Mo, Lingyan [Dept. of Otorhinolaryngology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)

    2013-04-15

    Background: There is an increasing frequency of requests for cochlear implantation (CI) in deaf children and more detailed image information is necessary for selecting appropriate candidates. Cochlear nerve deficiency (CND) is a contraindication to CI. Magnetic resonance imaging (MRI) has been used to evaluate the integrity of the cochlear nerve. The abnormalities of the cochlear nerve canal (CNC) and internal auditory canal (IAC) have been reported to be associated with CND. Purpose: To correlate CNC manifestation, size, and IAC diameter on high-resolution CT (HRCT) with CND diagnosed by MRI in children. Material and Methods: HRCT images from 35 sensorineurally deaf children who had normal cochlea but bilateral or unilateral CND diagnosed by MRI were studied retrospectively. The CNC and IAC manifestation and size were assessed and correlated with CND. Results: CND was diagnosed by MRI in 54/70 ears (77.1%). Thirty-two ears had an absent cochlear nerve (59.3%), while 22 ears had a small cochlear nerve (40.7%). The CNC diameter was <1.5 mm in 36 ears (66.7%). The CNC diameter ranged between 1.5 and 2.0 mm in seven ears (13.0%) and was >2.0 mm in 11 ears (20.4%). The IAC diameter was <3.0 mm in 25 ears (46.3%) and >3.0 mm in 29 ears (53.7%). Conclusion: The hypoplastic CNC might be more highly indicative of CND than that of a narrow IAC.

  9. PATHOLOGICAL AND SERUM BIOCHEMICAL EFFECTS OF SALINOMYCIN ON LAYER CHICKS

    Directory of Open Access Journals (Sweden)

    F. RIZVI, A. D. ANJUM, A. KHAN, M. MOHSAN AND M. SHAZAD

    2008-01-01

    Full Text Available Effects of continuous and over dosage of salinomycin was studied experimentally in layer chicks.Salinomycin was given to layers @ 60, 120 and 180 ppm in feed up to the age of 12 weeks. During the courseof trial, the birds of all groups were active and did not show any clinical signs. Body weight started decreasingsignificantly (P<0.001 in chicks receiving 60, 120 and 180 ppm salinomycin compared to the control groupfrom the 11th, 5th and 3rd week onward, respectively. Feed conversion ratio at 12th week was 3.537 in the controlcompared with 3.701, 4.250 and 4.465 in layer chicks given salinomycin at the rate of 60, 120 and 180 ppm,respectively. Absolute weight of liver at 12th week and absolute weight of kidneys throughout the experimentdecreased significantly (P<0.001 in chicks receiving 180 ppm salinomycin. Concentrations of AST, ALT,blood urea and creatinine were higher in layers receiving 180 ppm salinomycin, while serum total bilirubinconcentration was increased significantly (P<0.001 in layers receiving 120 and 180 ppm salinomycin. No grosslesions were observed in liver and kidneys of layers receiving various doses of salinomycin. Microscopically,there was congestion of liver sinusides and vacuolization of hepatocytes in chicks receiving 180 ppmsalinomycin. There was hydropic degeneration of tubular epithelium, degeneration and desquamation of most ofcells of Bowman’s capsule epithelium of kidneys in birds receiving 180 ppm salinomycin. Higher doses ofsalinomycin seem to alter liver and kidney functions subclinically in layer chicks.

  10. The Current Status of Microscopical Hair Comparisons

    Directory of Open Access Journals (Sweden)

    Walter F. Rowe

    2001-01-01

    Full Text Available Although the microscopical comparison of human hairs has been accepted in courts of law for over a century, recent advances in DNA technology have called this type of forensic examination into question. In a number of cases, post-conviction DNA testing has exonerated defendants who were convicted in part on the results of microscopical hair comparisons. A federal judge has held a Daubert hearing on the microscopical comparison of human hairs and has concluded that this type of examination does not meet the criteria for admission of scientific evidence in federal courts. A review of the available scientific literature on microscopical hair comparisons (including studies conducted by the Royal Canadian Mounted Police and the Federal Bureau of Investigation leads to three conclusions: (1 microscopical comparisons of human hairs can yield scientifically defensible conclusions that can contribute to criminal investigations and criminal prosecutions, (2 the reliability of microscopical hair comparisons is strongly affected by the training of the forensic hair examiner, (3 forensic hair examiners cannot offer estimates of the probability of a match of a questioned hair with a hair from a randomly selected person. In order for microscopical hair examinations to survive challenges under the U.S. Supreme Court’s Daubert decision, hair microscopists must be better trained and undergo frequent proficiency testing. More research on the error rates of microscopical hair comparisons should be undertaken, and guidelines for the permissible interpretations of such comparisons should be established. Until these issues have been addressed and satisfactorily resolved, microscopical hair comparisons should be regarded by law enforcement agencies and courts of law as merely presumptive in nature, and all microscopical hair comparisons should be confirmed by nuclear DNA profiling or mitochondrial DNA sequencing.

  11. Interpreting variation in growth of Eurasian Spoonbill chicks: disentangling the effects of age, sex and environment

    NARCIS (Netherlands)

    Lok, T.; Overdijk, O.; Piersma, T.

    2014-01-01

    Chick body condition can be a sensitive indicator of local environmental conditions and has been shown to be correlated with chick survival. Designing a reliable index of chick body condition for a given species from a single measurement point requires knowledge about the extent of variation in body

  12. Immunization of young chicks using graded dose of wild strain of Eimeria tenella

    Directory of Open Access Journals (Sweden)

    E.N. Kimbita

    2005-09-01

    Full Text Available A wild strain of Eimeria tenella was isolated and utilized for immunization studies. Its optimal sporulation was attained at room temperature 24-25 °C after 24-48 h. Two groups of chicks were immunized by dosing a graded dose of five oocysts/chick/day for 6 days followed by 50 oocysts/chick/day for 7 days. A third group was not immunized and served as a negative control. Immunized chicks gained mass at the same rate as unimmunized ones, but when challenged with 200 000 oocysts/chick, mass gains declined in the unimmunized group. The growth rate of immunized chicks was not affected by challenge (P > 0.05. Upon challenge, unimmunized chicks produced significantly more oocysts than immunized chicks (P < 0.005. Immunized chicks withstood a challenged with 200 000 oocysts/chick without developing any clinical signs whereas the unimmunized chicks developed typical clinical signs of coccidiosis. Unimmunized chicks had significantly more severe lesions in the caecum than any other group (P > 0.005 and also produced significantly more oocysts than any other group (P > 0.005.

  13. CT and MR imaging for pediatric cochlear implantation: emphasis on the relationship between the cochlear nerve canal and the cochlear nerve

    Energy Technology Data Exchange (ETDEWEB)

    Miyasaka, Mikiko; Nosaka, Shunsuke; Masaki, Hidekazu [National Center for Child Health and Development, Department of Radiology, Tokyo (Japan); Morimoto, Noriko; Taiji, Hidenobu [National Center for Child Health and Development, Department of Otolaryngology, Tokyo (Japan)

    2010-09-15

    Cochlear implantation has become an accepted treatment for deafness. As the frequency of cochlear implantation has increased, requests for images have also increased in the work-up for candidates. An absent cochlear nerve (CN) is a contraindication to cochlear implantation. Therefore, MRI is performed to evaluate the CN in patients with sensorineural hearing loss. Recently, some authors have reported the relationship between cochlear nerve canal (CNC) stenosis and CN hypoplasia. To review the relationship between CNC and CN. During a period of 78 months, 21 children (42 ears) with unilateral or bilateral sensorineural hearing loss underwent both HRCT and MRI of the cochlear nerve. We retrospectively reviewed two factors: the evaluation of inner ear malformations and the relationship between CNC stenosis and CN hypoplasia. Inner ear malformations were recognized in ten ears. The mean CNC diameter was approximately 2 mm (ranging from 0.6 to 2.7 mm). CN hypoplasia was seen in eight of the 42 ears; all eight were associated with CNC stenosis ({<=}1.5 mm). Of the 34 ears with normal CN, 32 had CNC >1.5 mm in diameter and the remaining two ears, with incomplete partition type I, had CNC stenosis. Children with CNC stenosis had a high incidence of CN hypoplasia. CNC stenosis ({<=}1.5 mm) suggests CN hypoplasia. On the other hand, CN hypoplasia was not seen in children with CNC diameter >1.5 mm. Therefore, we conclude that children with CNC stenosis or malformations on HRCT should receive MR imaging of the CN. (orig.)

  14. Effect of unilateral and simultaneous bilateral cochlear implantation on tinnitus : A randomized controlled trial

    NARCIS (Netherlands)

    van Zon, Alice; Smulders, Yvette E; Ramakers, Geerte G J; Stegeman, Inge; Smit, Adriana L; Van Zanten, Gijsbert A; Stokroos, Robert J; Hendrice, Nadia; Free, Rolien H; Maat, Bert; Frijns, Johan H M; Mylanus, Emmanuel A M; Huinck, Wendy J; Topsakal, Vedat; Tange, Rinze A; Grolman, Wilko

    2015-01-01

    OBJECTIVES/HYPOTHESIS: To determine the effect of cochlear implantation on tinnitus perception in patients with severe bilateral postlingual sensorineural hearing loss and to demonstrate possible differences between unilateral and bilateral cochlear implantation. STUDY DESIGN: Prospective study. MET

  15. Effect of unilateral and simultaneous bilateral cochlear implantation on tinnitus: A Prospective Study

    NARCIS (Netherlands)

    Zon, A. van; Smulders, Y.E.; Ramakers, G.G.; Stegeman, I.; Smit, A.L.; Zanten, G.A.; Stokroos, R.J.; Hendrice, N.; Free, R.H.; Maat, B.; Frijns, J.H.; Mylanus, E.A.M.; Huinck, W.J.; Topsakal, V.; Tange, R.A.; Grolman, W.

    2016-01-01

    OBJECTIVES/HYPOTHESIS: To determine the effect of cochlear implantation on tinnitus perception in patients with severe bilateral postlingual sensorineural hearing loss and to demonstrate possible differences between unilateral and bilateral cochlear implantation. STUDY DESIGN: Prospective study. MET

  16. In vitro protection of auditory hair cells by salicylate from the gentamicin-induced but not neomycin-induced cell loss.

    Science.gov (United States)

    Mazurek, Birgit; Lou, Xiangxin; Olze, Heidi; Haupt, Heidemarie; Szczepek, Agnieszka J

    2012-01-01

    Salicylate has been shown to protect animals and people from the gentamicin-induced hearing loss. The objective of our study was to determine if salicylate is otoprotective in vitro. In this fashion, we wanted to validate the use of explant culture system for future studies on the ototoxicity prevention. In addition, we wanted to find out if salicylate protects from the ototoxicity of other aminoglycosides. As a model, we used the membranous cochlear tissues containing the organ of Corti, spiral limbus and spiral ganglion neurons dissected from the cochleas of p3-p5 Wistar pups. The explants were divided into apical, medial and basal parts and cultured in presence or absence of 100μM gentamicin, 100μM neomycin and 5mM salicylate. Following the tissue fixation and staining with phalloidin-TRITC, the number of inner and outer hair cells (IHCs, OHCs) was scored under the fluorescent microscope. Presence of 5mM salicylate in explants cultures exposed to 100μM gentamicin significantly reduced the loss of IHCs and OHCs, as compared to explants exposed to gentamicin alone. In contrast, neomycin-induced auditory hair cell loss remained unaffected by the presence of salicylate. Our results corroborate earlier in vivo findings and validate the use of cochlear explants for future studies on ototoxicity and its prevention. Moreover, the inability of salicylate to prevent neomycin-induced ototoxicity implies possible differences between the mechanisms of auditory hair cell loss induced by gentamicin and neomycin.

  17. Hair as a marker for pesticides exposure.

    Science.gov (United States)

    Smith-Baker, Charlotte; Saleh, Mahmoud A

    2011-01-01

    Rats were orally treated with mixtures of chlorinated pesticides. Hair was collected and analyzed for pesticide residues over a period of up to four weeks. Quantitative and qualitative analysis of the recovered pesticides in hair were determined using gas chromatography with electron capture detector. Results suggest that hair can be used as a biomarker for the monitoring of organochlorinated pesticide residues at low parts per billion levels. Chlorinated pesticides were also detected in human hair of environmentally exposed and occupationally exposed individuals, which indicates that hair can be used for monitoring pesticides exposure.

  18. Clofazimine-induced Hair Pigmentation.

    Science.gov (United States)

    Philip, Mariam; Samson, Joan Felicita; Simi, Puthenveedu Salahudeen

    2012-07-01

    A 45-year-old man was treated with WHO multibacillary multidrug therapy for borderline leprosy and high dose daily Clofazimine for lepra reaction. Along with the expected side effect of skin pigmentation, the patient also noticed darkening of previously grey hair. This colour persisted eight months after completing multibacillary multidrug therapy.

  19. Connexin26 (GJB2) deficiency reduces active cochlear amplification leading to late-onset hearing loss.

    Science.gov (United States)

    Zhu, Y; Chen, J; Liang, C; Zong, L; Chen, J; Jones, R O; Zhao, H-B

    2015-01-22

    Connexin26 (Cx26, GJB2) mutations account for >50% of nonsyndromic hearing loss. The deafness is not always congenital. A large group of these patients (∼30%) demonstrate a late-onset hearing loss, starting in childhood. They have normal hearing early in life and are therefore good candidates for applying protective and therapeutic interventions. However, the underlying deafness mechanism is unclear. In this study, we used a time-controlled, inducible gene knockout technique to knockout Cx26 expression in the cochlea after birth. We found that deletion of Cx26 after postnatal day 5 (P5) in mice could lead to late-onset hearing loss. Similar to clinical observations, the mice demonstrated progressive, mild to moderate hearing loss. The hearing loss initiated at high frequencies and then extended to the middle- and low-frequency range. The cochlea showed normal development and had no apparent hair cell loss. However, distortion product otoacoustic emission (DPOAE) was reduced. The reduction was also progressive and large at high-frequencies. Consistent with DPOAE reduction, we found that outer hair cell electromotility-associated nonlinear capacitance was shifted to the right and the slope of voltage dependence was reduced. The endocochlear potential was reduced in Cx26 conditional knockout (cKO) mice but the reduction was not associated with progressive hearing loss. These data suggest that Cx26 deficiency may impair active cochlear amplification leading to late-onset hearing loss. Our study also helps develop newer protective and therapeutic interventions to this common nonsyndromic hearing loss.

  20. Managing hair loss in midlife women.

    Science.gov (United States)

    Mirmirani, Paradi

    2013-02-01

    Hair is considered one of the most defining aspects of human appearance. Hair loss, or alopecia in women is often met with significant emotional distress and anxiety. In midlife, women may encounter various hormonal and age-related physiologic changes that can lead to alterations in hair texture and growth. The most significant hormonal alteration is the onset of menopause in which there is a cessation of ovarian estrogen production. This decrease in estrogen is known to have deleterious effects on the skin and cutaneous appendages. As our understanding of the molecular and hormonal controls on the hair follicle has grown, there has been increased interest in the various modulators of hair growth, including the potential role of estrogen. Further study of hair changes in midlife women provides an important opportunity for identification of the complex regulation of hair growth as well as identification of treatment targets that may specifically benefit women. In this review, management of hair loss in midlife women is discussed with a focus on three most commonly encountered clinical conditions: female pattern hair loss, hair shaft alterations due to hair care, and telogen effluvium.

  1. Alterations in hair follicle dynamics in women.

    Science.gov (United States)

    Piérard-Franchimont, Claudine; Piérard, Gérald E

    2013-01-01

    Endocrine changes supervening after parturition and menopause participate in the control of sebum production and hair growth modulation. The ensuing conditions include some peculiar aspects of hair loss (effluvium), alopecia, and facial hirsutism. The hair cycling is of major clinical relevance because most hair growth disorders result from disturbances in this chronobiological feature. Of note, any correlation between a biologic abnormality and hair cycling disturbance does not prove a relationship of causality. The proportion of postmenopausal women is rising in the overall population. Therefore, the prevalence of these hair follicle disturbances is globally on the rise. Current therapies aim at correcting the underlying hormonal imbalances, and at improving the overall cosmetic appearance. However, in absence of pathogenic diagnosis and causality criteria, chances are low that a treatment given by the whims of fate will adequately control hair effluvium. The risk and frequency of therapeutic inertia are further increased. When the hair loss is not controlled and/or compensated by growth of new hairs, several clinical aspects of alopecia inexorably develop. Currently, there is little evidence supporting any specific treatment for these endocrine hair disorders in post-partum and postmenopausal women. Current hair treatment strategies are symptomatic and nonspecific so current researchers aim at developing new, targeted methods.

  2. Alterations in Hair Follicle Dynamics in Women

    Directory of Open Access Journals (Sweden)

    Claudine Piérard-Franchimont

    2013-01-01

    Full Text Available Endocrine changes supervening after parturition and menopause participate in the control of sebum production and hair growth modulation. The ensuing conditions include some peculiar aspects of hair loss (effluvium, alopecia, and facial hirsutism. The hair cycling is of major clinical relevance because most hair growth disorders result from disturbances in this chronobiological feature. Of note, any correlation between a biologic abnormality and hair cycling disturbance does not prove a relationship of causality. The proportion of postmenopausal women is rising in the overall population. Therefore, the prevalence of these hair follicle disturbances is globally on the rise. Current therapies aim at correcting the underlying hormonal imbalances, and at improving the overall cosmetic appearance. However, in absence of pathogenic diagnosis and causality criteria, chances are low that a treatment given by the whims of fate will adequately control hair effluvium. The risk and frequency of therapeutic inertia are further increased. When the hair loss is not controlled and/or compensated by growth of new hairs, several clinical aspects of alopecia inexorably develop. Currently, there is little evidence supporting any specific treatment for these endocrine hair disorders in post-partum and postmenopausal women. Current hair treatment strategies are symptomatic and nonspecific so current researchers aim at developing new, targeted methods.

  3. Megasessions for Robotic Hair Restoration.

    Science.gov (United States)

    Pereira, Joa O Carlos; Pereira Filho, Joa O Carlos; Cabrera Pereira, Joa O Pedro

    2016-11-01

    A robotic system can select and remove individual hair follicles from the donor area with great precision and without fatigue. This report describes the use of the robotic system in a megasession for hair restoration. Patients were instructed to cut their hair to 1.0 to 1.2 mm before surgery. The robot selected and removed 600 to 800 grafts per hour so the follicular units (FU)s could be transplanted manually to recipient sites. The robot arm consists of a sharp inner punch and a blunt outer punch which together separate FUs from the sur- rounding tissue. Stereoscopic cameras controlled by image processing software allow the system to identify the angle and direction of hair growth. The physician and one assistant control the harvesting with a hand-held remote control and computer monitor while the patient is positioned in an adjustable chair. When the robot has harvested all the FUs they are removed by technicians with small forceps. Hairline design, creation of recipient sites, and graft placement are performed manually by the physician. Clinical photographs before and after surgery show that patients experience excellent outcomes with the robotic megasession. Phy- sician fatigue during graft extraction is reduced because the robot performs the repetitive movements without fatigue. Variability of graft extraction is minimized because the robot's optical system can be programmed to choose the best FUs. The transection rate is reduced because the robot's graft extraction system uses two needles, a sharp one to piece the skin and a blunt needle to dissect the root without trauma. A robotic megasession for hair restoration is minimally invasive, does not result in linear scars in the donor area, and is associated with minimal fatigue and discomfort for both patient and physician. Healing is rapid and patients experience a high level of satisfaction with the results. J Drugs Dermatol. 2016;15(11):1407-1412..

  4. Hair Image Generation Using Connected Texels

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaopeng; CHEN Yanyun; WU Enhua

    2001-01-01

    Generation of photo-realistic images of human hair is a challenging topic in computer graphics. The difficulty in solving the problem in this aspect comes mainly from the extremely large number of hairs and the high complexity of the hair shapes. Regarding to the modeling and rendering of hair-type objects,Kajiya proposed a so-called texel model for producing furry surfaces. However,Kajiya's model could be only used for the generation of short hairs. In this paper,a concise and practical approach is presented to solve the problem of rendering long hairs, and in particular the method of rendering the smooth segmental texels for the generation of long hairs is addressed.

  5. Costs involved in using a cochlear implant in South Africa

    Directory of Open Access Journals (Sweden)

    Gillian Robyn Kerr

    2012-12-01

    Full Text Available Cochlear implantation is an expensive but effective lifelong intervention for individuals with a severe-to-profound hearing loss. The primary aim of this study was to survey the short- and long-term costs of cochlear implantation. Individuals (N=154 using cochlear implants obtained from the University of Stellenbosch-Tygerberg Hospital Cochlear Implant Unit in Cape Town, South Africa were surveyed using a questionnaire and patient record review. The questionnaire used a combination of closed and open-ended questions to gather both quantitative and qualitative information. Costs were categorised as short- and long-term costs. All costs were converted to constant rands (June 2010 using the Consumer Price Index to allow for comparison in real terms over time. In the first 10 years of implantation the average estimated costs incurred by adults totalled R379 626, and by children R455 225. The initial purchase of the implant system was the most substantial cost, followed by upgrading of the processor. Travel and accommodation costs peaked in the first 2 years. On average the participants spent R2 550 per year on batteries and spares. Rehabilitation for children cost an average of R7 200. Insurance costs averaged R4 040 per year, and processor repairs R3 000 each. In addition to the upfront expense of obtaining the cochlear implant system, individuals using a cochlear implant in South Africa should be prepared for the long-term costs of maintenance, accessing the unit, support services and additional costs associated with use. Knowledge of these costs is important to ensure that individuals are successful users of their cochlear implants in the long term.

  6. The dynamic range of inner hair cell and organ of Corti responses.

    Science.gov (United States)

    Cheatham, M A; Dallos, P

    2000-03-01

    Inner hair cell (IHC) and organ of Corti (OC) responses are measured from the apical three turns of the guinea pig cochlea, allowing access to regions with best, or most sensitive, frequencies at approximately 250, 1000, and 4000 Hz. In addition to measuring both ac and dc receptor potentials, the average value of the half-wave rectified response (AVEHR) is computed to better reflect the signal that induces transmitter release. This measure facilitates comparisons with single-unit responses in the auditory nerve. Although IHC ac responses exhibit compressive growth, response magnitudes at high levels depend on stimulus frequency. For example, IHCs with moderate and high best frequencies (BF) exhibit more linear responses below the BF of the cell, where higher sound-pressure levels are required to approach saturation. Because a similar frequency dependence is observed in extracellular OC responses, this phenomenon may originate in cochlear mechanics. At the most apical recording location, however, the pattern documented at the base of the cochlea is not seen in IHCs with low BFs around 250 Hz. In fact, more linear behavior is measured above the BF of the cell. These frequency-dependent features require modification of cochlear models that do not provide for longitudinal variations and generally depend on a single stage of saturation located at the synapse. Finally, behavior of dc and AVEHR responses suggests that a single IHC is capable of coding intensity over a large dynamic range [Patuzzi and Sellick, J. Acoust. Soc. Am. 74, 1734-1741 (1983); Smith et al., in Hearing--Physiological Bases and Psychophysics (Springer, Berlin, 1983); Smith, in Auditory Function (Wiley, New York, 1988)] and that information compiled over wide areas along the cochlear partition is not essential for loudness perception, consistent with psychophysical results [Viemeister, Hearing Res. 34, 267-274 (1988)].

  7. New Criteria of Indication and Selection of Patients to Cochlear Implant

    Directory of Open Access Journals (Sweden)

    André L. L. Sampaio

    2011-01-01

    Full Text Available Numerous changes continue to occur in cochlear implant candidacy. In general, these have been accompanied by concomitant and satisfactory changes in surgical techniques. Together, this has advanced the utility and safety of cochlear implantation. Most devices are now approved for use in patients with severe to profound unilateral hearing loss rather then the prior requirement of a bilateral profound loss. Furthermore, studies have begun utilizing short electrode arrays for shallow insertion in patients with considerable low-frequency residual hearing. This technique will allow the recipient to continue to use acoustically amplified hearing for the low frequencies simultaneously with a cochlear implant for the high frequencies. The advances in design of, and indications for, cochlear implants have been matched by improvements in surgical techniques and decrease in complications. The resulting improvements in safety and efficacy have further encouraged the use of these devices. This paper will review the new concepts in the candidacy of cochlear implant. Medline data base was used to search articles dealing with the following topics: cochlear implant in younger children, cochlear implant and hearing preservation, cochlear implant for unilateral deafness and tinnitus, genetic hearing loss and cochlear implant, bilateral cochlear implant, neuropathy and cochlear implant and neural plasticity, and the selection of patients for cochlear implant.

  8. Comparison of Bilateral and Unilateral Cochlear Implantation in Adults : A Randomized Clinical Trial

    NARCIS (Netherlands)

    Smulders, Yvette E; van Zon, Alice; Stegeman, Inge; Rinia, Albert B; Van Zanten, Gijsbert A; Stokroos, Robert J; Hendrice, Nadia; Free, Rolien; Maat, Bert; Frijns, Johan H M; Briaire, Jeroen J; Mylanus, Emmanuel A M; Huinck, Wendy J; Smit, Adriana L; Topsakal, Vedat; Tange, Rinze A; Grolman, Wilko

    2016-01-01

    Importance: The cost of bilateral cochlear implantation (BCI) is usually not reimbursed by insurance companies because of a lack of well-designed studies reporting the benefits of a second cochlear implant. Objective: To determine the benefits of simultaneous BCI compared with unilateral cochlear im

  9. Can auditory stady-state responses reflect place-specific cochlear dispersion?

    DEFF Research Database (Denmark)

    Paredes Gallardo, Andreu; Epp, Bastian; Dau, Torsten

    The cochlear travelling wave propagates from the base to the apex, resulting in an increasing phase with distance from the cochlear base. Together with the tonotopic organization of the cochlea, this results in a frequency dependent delay of the resonance, a phenomenon known as cochlear dispersion...

  10. Hearing Experience and Receptive Vocabulary Development in Deaf Children with Cochlear Implants

    Science.gov (United States)

    Fagan, Mary K.; Pisoni, David B.

    2010-01-01

    This study investigated receptive vocabulary delay in deaf children with cochlear implants. Participants were 23 children with profound hearing loss, ages 6-14 years, who received a cochlear implant between ages 1.4 and 6 years. Duration of cochlear implant use ranged from 3.7 to 11.8 years. "Peabody Picture Vocabulary Test, Third…

  11. Biophysics of Human Hair Structural, Nanomechanical, and Nanotribological Studies

    CERN Document Server

    Bhushan, Bharat

    2010-01-01

    This book presents the biophysics of hair. It deals with the structure of hair, its mechanical properties, the nanomechanical characterization, tensile deformation, tribological characterization, the thickness distribution and binding interactions on hair surface. Another important topic of the book is the health of hair, human hair and skin, hair care, cleaning and conditioning treatments and damaging processes. It is the first book on the biophysical properties of hair.

  12. Putting the Human Hair Follicle Cycle on the Map.

    Science.gov (United States)

    Panteleyev, Andrey A

    2016-01-01

    A detailed characterization of the normal (in situ) human hair follicle cycle, supplemented with expressional data on specific hair follicle markers, has been awaited by basic hair researchers and dermatologists. Combining this hair cycle guide, together with a thorough analysis of the human-on-mouse hair xenograft model, provides solid ground for examining human hair cycle biology and pathology and for hair cycle-related pharmacological testing.

  13. Coupling and elastic loading affect the active response by the inner ear hair cell bundles.

    Directory of Open Access Journals (Sweden)

    Clark Elliott Strimbu

    Full Text Available Active hair bundle motility has been proposed to underlie the amplification mechanism in the auditory endorgans of non-mammals and in the vestibular systems of all vertebrates, and to constitute a crucial component of cochlear amplification in mammals. We used semi-intact in vitro preparations of the bullfrog sacculus to study the effects of elastic mechanical loading on both natively coupled and freely oscillating hair bundles. For the latter, we attached glass fibers of different stiffness to the stereocilia and observed the induced changes in the spontaneous bundle movement. When driven with sinusoidal deflections, hair bundles displayed phase-locked response indicative of an Arnold Tongue, with the frequency selectivity highest at low amplitudes and decreasing under stronger stimulation. A striking broadening of the mode-locked response was seen with increasing stiffness of the load, until approximate impedance matching, where the phase-locked response remained flat over the physiological range of frequencies. When the otolithic membrane was left intact atop the preparation, the natural loading of the bundles likewise decreased their frequency selectivity with respect to that observed in freely oscillating bundles. To probe for signatures of the active process under natural loading and coupling conditions, we applied transient mechanical stimuli to the otolithic membrane. Following the pulses, the underlying bundles displayed active movement in the opposite direction, analogous to the twitches observed in individual cells. Tracking features in the otolithic membrane indicated that it moved in phase with the bundles. Hence, synchronous active motility evoked in the system of coupled hair bundles by external input is sufficient to displace large overlying structures.

  14. Hair breakage index: an alternative tool for damage assessment of human hair.

    Science.gov (United States)

    Mhaskar, Sudhakar; Kalghatgi, Bhargavi; Chavan, Madhavi; Rout, Suryamani; Gode, Vaishali

    2011-01-01

    Improper hair care, mechanical abrasion, sun damage and chemical treatment changes the physical and morphological characteristics of hair. Several methods involving microscopic techniques, protein loss and assessment of tensile properties of the hair are generally used to evaluate the extent of damage caused. These are also used to determine the protective effect of hair care products. In the present investigation, the hair breakage index (HBI) was used as an alternative tool to determine the change in the properties of hair on weathering. HBI is a measure of the diameter of hair in a given cross sectional area of a marked region of hair on the scalp. The hair diameter changes as we progress towards the tip of the hair due to breakage. The ratio of the diameter of hair bundle in the distal region to the diameter of hair bundle in the proximal region from the scalp is used as an indicator of hair breakage. Higher HBI value is an indicator of hair damage.A study was conducted for duration of 16 weeks to assess the effect of weathering due to grooming practices on HBI values. The HBI and break stress for a group of 30 subjects were measured at baseline and at the end of 16 weeks (NU). Since Coconut oil (CNO) is known to have a positive benefit on tensile properties of hair, another matched group of 30 subjects who oiled their hair daily with CNO was used as a positive control (CNO). The HBI and break stress for this group were also measured at the baseline and after 16 weeks. It was observed that the HBI significantly increased in the NU group versus the CNO user group. The break stress also significantly decreased in the NU group suggesting its correlation with the HBI data. This study demonstrates the usefulness of HBI as a simple and effective tool for determining hair damage and its protection by different hair care products.

  15. Shape deformation of the organ of Corti associated with length changes of outer hair cell

    Science.gov (United States)

    Zimmermann, U.; Fermin, C.

    1996-01-01

    Cochlear outer hair cells (OHC) are commonly assumed to function as mechanical effectors as well as sensory receptors in the organ of Corti (OC) of the inner ear. OHC in vitro and in organ explants exhibit mechanical responses to electrical, chemical or mechanical stimulation which may represent an aspect of their effector process that is expected in vivo. A detailed description, however, of an OHC effector operation in situ is still missing. Specifically, little is known as to how OHC movements influence the geometry of the OC in situ. Previous work has demonstrated that the motility of isolated OHCs in response to electrical stimulation and to K(+)-gluconate is probably under voltage control and causes depolarisation (shortening) and hyperpolarization (elongation). This work was undertaken to investigate if the movements that were observed in isolated OHC, and which are induced by ionic stimulation, could change the geometry of the OC. A synchronized depolarization of OHC was induced in guinea pig cochleae by exposing the entire OC to artificial endolymph (K+). Subsequent morphometry of mid-modiolar sections from these cochleae revealed that the distance between the basilar membrane (BM) and the reticular lamina (RL) had decreased considerably. Furthermore, in the three upper turns OHC had significantly shortened in all rows. The results suggest that OHC can change their length in the organ of Corti (OC) thus deforming the geometry of the OC. The experiments reveal a tonic force generation within the OC that may change the position of RL and/or BM, contribute to damping, modulate the BM-RL-distance and control the operating points of RL and sensory hair bundles. Thus, the results suggest active self-adjustments of cochlear mechanics by slow OHC length changes. Such mechanical adjustments have recently been postulated to correspond to timing elements of animal communication, speech or music.

  16. Noise-induced nitrotyrosine increase and outer hair cell death in guinea pig cochlea

    Institute of Scientific and Technical Information of China (English)

    HAN Wei-ju; SHI Xiao-rui; Alfred Nuttall

    2013-01-01

    Background Modern research has provided new insights into the biological mechanisms of noise-induced hearing loss,and a number of studies showed the appearance of increased reactive oxygen species (ROS) and reactive nitrogen species (RNS) during and after noise exposure.This study was designed to investigate the noise exposure induced nitrotyrosine change and the mechanism of outer hair cells death in guinea pig cochlea.Method Thirty guinea pigs were used in this study.The experimental animals were either exposed for 4 hours per day to broadband noise at 122 dB SPL (A-weighted) for 2 consecutive days or perfused cochleae with 5 mg/ml of the SIN1 solutions,an exogenous NO and superoxide donor,for 30 minutes.Then the cochleae of the animals were dissected.Propidium iodide (PI),a DNA intercalating fluorescent probe,was used to trace morphological changes in OHC nuclei.The distribution of nitrotyrosine (NT) in the organ of Corti and the cochlear lateral wall tissue from the guinea pigs were examined using fluorescence immunohistochemistry method.Whole mounts of organ of Corti were prepared.Morphological and fluorescent changes were examined under a confocal microscope.Results Either after noise exposure or after SIN1 perfusion,outer hair cells (OHCs) death with characteristics of both apoptotic and necrotic degradation appeared.Nitrotyrosine immunolabeling could be observed in the OHCs from the control animals.After noise exposure,NT immunostaining became much greater than the control animals in OHCs.The apoptotic OHC has significant increase of nitrotyrosine in and around the nucleus following noise exposure.In the normal later wall of cochleae,relatively weak nitrotyrosine immunolabeling could be observed.After noise exposure,nitrotyrosine immunoactivity became stronger in stria vascularis.Conclusion Noise exposure induced increase of nitrotyrosine production is associated with OHCs death suggesting reactive nitrogen species participation in the cochlear

  17. Influence of a mobile robot on the spatial behaviour of quail chicks

    Energy Technology Data Exchange (ETDEWEB)

    De Margerie, E; Lumineau, S; Houdelier, C; Richard Yris, M-A, E-mail: emmanuel.demargerie@univ-rennes1.fr [CNRS UMR 6552 Ethologie Animale et Humaine, Universite Rennes 1, Rennes (France)

    2011-09-15

    Quail chicks encountered an autonomous mobile robot during their early development. The robot incorporated a heat source that stimulated following of chicks. The spatial behaviour of grown-up chicks was tested in an exploration test and a detour test. Chicks that grew with the mobile robot exhibited better spatial abilities than chicks grown with a static heat source. We discuss these results in the perspective of animal-robot interaction and of the role of early spatial experience on the behavioural development. (communication)

  18. Nonlinear spectro-temporal features based on a cochlear model for automatic speech recognition in a noisy situation.

    Science.gov (United States)

    Choi, Yong-Sun; Lee, Soo-Young

    2013-09-01

    A nonlinear speech feature extraction algorithm was developed by modeling human cochlear functions, and demonstrated as a noise-robust front-end for speech recognition systems. The algorithm was based on a model of the Organ of Corti in the human cochlea with such features as such as basilar membrane (BM), outer hair cells (OHCs), and inner hair cells (IHCs). Frequency-dependent nonlinear compression and amplification of OHCs were modeled by lateral inhibition to enhance spectral contrasts. In particular, the compression coefficients had frequency dependency based on the psychoacoustic evidence. Spectral subtraction and temporal adaptation were applied in the time-frame domain. With long-term and short-term adaptation characteristics, these factors remove stationary or slowly varying components and amplify the temporal changes such as onset or offset. The proposed features were evaluated with a noisy speech database and showed better performance than the baseline methods such as mel-frequency cepstral coefficients (MFCCs) and RASTA-PLP in unknown noisy conditions.

  19. Safety of West Nile Virus vaccines in sandhill crane chicks

    Science.gov (United States)

    Olsen, G.H.; Miller, K.J.; Docherty, D.E.; Bochsler, V.S.; Folk, Martin J.; Nesbitt, Stephen A.

    2008-01-01

    West Nile virus arrived in North America in 1999 and has spread across the continent in the ensuing years. The virus has proven deadly to a variety of native avian species including sandhill cranes (Grus canadensis). In order to provide safe and efficacious protection for captive and released populations of whooping cranes (G. americana), we have conducted a series of four research projects. The last of these was a study of the effects of two different West Nile virus vaccines on young Florida sandhill crane (G. c. pratensis) chicks and subsequent challenge with the virus. We found that vaccinating crane chicks as early as day 7 post-hatch caused no adverse reactions or noticeable morbidity. We tested both a commercial equine vaccine West Nile - Innovator (Fort Dodge Laboratories, Fort Dodge, Iowa) and a new recombinant DNA vaccine (Centers for Disease Control). We had a 33% mortality in control chicks (n =6) from West Nile virus infection, versus 0% mortality in two groups of vaccinated chicks (n = 12), indicating the two vaccines tested were not only safe but effective in preventing West Nile virus.

  20. Embryotoxic effects of crude oil in mallard ducks and chicks

    Science.gov (United States)

    Hoffman, D.J.

    1978-01-01

    Recent studies in this laboratory have revealed that surface applications of microliter amounts of some crude and fuel oils that coat less than 10% of the egg surface reduce hatching considerably in different avian species. Applications of paraffin compounds that coat equal areas of the egg surface do not reduce hatching suggesting that toxicity is due to causes other than asphyxia. In the present study, 1?10 :l of South Louisiana crude oil, an API reference oil, were applied to the surface of fertile mallard (Anas platyrhynchos) and chicken (Gallus gallus) eggs. Early embryolethality was greater in mallard embryos than in chick embryos, but later embryolethality that coincided with the time of rapid outgrowth of the chorioallantoic membrane was more prevalent in chick embryos. The overall incidence of embryolethality was similar in both species. Retardation of growth as reflected by embryonic body weight, crown-rump length, beak length, and general appearance was more pronounced in chick than mallard embryos. Teratogenic defects were more frequent in chick embryos, and incomplete or abnormal ossification of the skull was the most common. External application of equivalent amounts of a mixture of paraffin compounds present in crude oil had virtually no embryotoxic effects in either species, suggesting that other components including aromatic hydrocarbons and organometallics may cause the embryotoxicity.

  1. Ex Ovo Model for Directly Visualizing Chick Embryo Development

    Science.gov (United States)

    Dorrell, Michael I.; Marcacci, Michael; Bravo, Stephen; Kurz, Troy; Tremblay, Jacob; Rusing, Jack C.

    2012-01-01

    We describe a technique for removing and growing chick embryos in culture that utilizes relatively inexpensive materials and requires little space. It can be readily performed in class by university, high school, or junior high students, and teachers of any grade level should be able to set it up for their students. Students will be able to…

  2. Neurotoxic effect of the dithiocarbamate tecoram on the chick embryo

    NARCIS (Netherlands)

    Steenis, G. van; Logten, M.J. van

    1971-01-01

    Tecoram, when administered at doses of 0.01, 0.1, 1 or 10 mg per egg in propylene glycol or in saline to chick embryos caused paralysis, shortening of the extremities, muscular atrophy, dwarfing and death. Microscopically there were signs of peripheral neuropathy, mainly confined to the distal parts

  3. Effects of Senna occidentalis on chick bursa of Fabricius.

    Science.gov (United States)

    Silva, Tereza C; Gorniak, Silvana L; Oloris, Silvia C S; Raspantini, Paulo C; Haraguchi, Mitsue; Dagli, Maria L Z

    2003-12-01

    Senna occidentalis (L) Link (formerly called Cassia occidentalis) is a toxic leguminous plant found ubiquitously as a contaminant of crops. All parts of the plant are toxic, but most of the S. occidentalis toxicity is found in the seeds. S. occidentalis has been shown to be toxic to several animal species, causing degenerative lesions mainly in muscles. This is the first report describing alterations in chick lymphoid organs caused by S. occidentalis seeds. The objectives of this study were to describe the effects of the treatment with seeds and its fraction external tegument (TE) on the development of chicks and their lymphoid organs bursa of Fabricius and spleen. Chicks that received a commercial ration with 1% TE had reduced body and lymphoid organ weights. The bursa of Fabricius presented reduction in the diameters of the follicles, and in the thickness of the cortical and medullary regions. The spleen presented depleted lymphoid tissue in the white pulp. These results indicate that the active principle of S. occidentalis is more concentrated on its TE fraction, and that it can cause weight loss as well as alterations in the lymphoid organs in chicks. The consequences of these alterations should be further investigated.

  4. Effects of begging on growth rates of nestling chicks

    NARCIS (Netherlands)

    Rodriguez-Girones, MA; Zuniga, JM; Redondo, T

    2001-01-01

    We investigated whether an increase in begging levels delays growth of chicks. In experiment 1, we hand-reared nine pairs of ring dove squabs, divided into a control and a begging group. All squabs received similar amounts of food, but those in the begging group had to beg for a prolonged period in

  5. Artificially Increased Yolk Hormone Levels and Neophobia in Domestic Chicks.

    Science.gov (United States)

    Bertin, Aline; Arnould, Cécile; Moussu, Chantal; Meurisse, Maryse; Constantin, Paul; Leterrier, Christine; Calandreau, Ludovic

    2015-11-30

    In birds there is compelling evidence that the development and expression of behavior is affected by maternal factors, particularly via variation in yolk hormone concentrations of maternal origin. In the present study we tested whether variation in yolk hormone levels lead to variation in the expression of neophobia in young domestic chicks. Understanding how the prenatal environment could predispose chicks to express fear-related behaviors is essential in order to propose preventive actions and improve animal welfare. We simulated the consequences of a maternal stress by experimentally enhancing yolk progesterone, testosterone and estradiol concentrations in hen eggs prior to incubation. The chicks from these hormone-treated eggs (H) and from sham embryos (C) that received the vehicle-only were exposed to novel food, novel object and novel environment tests. H chicks approached a novel object significantly faster and were significantly more active in a novel environment than controls, suggesting less fearfulness. Conversely, no effect of the treatment was found in food neophobia tests. Our study highlights a developmental influence of yolk hormones on a specific aspect of neophobia. The results suggest that increased yolk hormone levels modulate specifically the probability of exploring novel environments or novel objects in the environment.

  6. Artificially Increased Yolk Hormone Levels and Neophobia in Domestic Chicks

    Directory of Open Access Journals (Sweden)

    Aline Bertin

    2015-11-01

    Full Text Available In birds there is compelling evidence that the development and expression of behavior is affected by maternal factors, particularly via variation in yolk hormone concentrations of maternal origin. In the present study we tested whether variation in yolk hormone levels lead to variation in the expression of neophobia in young domestic chicks. Understanding how the prenatal environment could predispose chicks to express fear-related behaviors is essential in order to propose preventive actions and improve animal welfare. We simulated the consequences of a maternal stress by experimentally enhancing yolk progesterone, testosterone and estradiol concentrations in hen eggs prior to incubation. The chicks from these hormone-treated eggs (H and from sham embryos (C that received the vehicle-only were exposed to novel food, novel object and novel environment tests. H chicks approached a novel object significantly faster and were significantly more active in a novel environment than controls, suggesting less fearfulness. Conversely, no effect of the treatment was found in food neophobia tests. Our study highlights a developmental influence of yolk hormones on a specific aspect of neophobia. The results suggest that increased yolk hormone levels modulate specifically the probability of exploring novel environments or novel objects in the environment.

  7. The basic science of hair biology: what are the causal mechanisms for the disordered hair follicle?

    Science.gov (United States)

    Breitkopf, Trisia; Leung, Gigi; Yu, Mei; Wang, Eddy; McElwee, Kevin J

    2013-01-01

    A hair disorder can be difficult to define, but patients are typically motivated to seek treatment when their hair growth patterns are significantly different from their cultural group or when growth patterns change significantly. The causes of hair disorders are many and varied, but fundamentally the disorder is a consequence of aberrant alterations of normal hair biology. The potential trigger factors for hair disorders can be attributed to inflammation, genetics, the environment, or hormones, of which the relative contributions vary for different diagnoses, between individuals, and over time. This article discusses the causal mechanisms for the disordered hair follicle.

  8. Cochlear Implantation, Enhancements, Transhumanism and Posthumanism: Some Human Questions.

    Science.gov (United States)

    Lee, Joseph

    2016-02-01

    Biomedical engineering technologies such as brain-machine interfaces and neuroprosthetics are advancements which assist human beings in varied ways. There are exciting yet speculative visions of how the neurosciences and bioengineering may influence human nature. However, these could be preparing a possible pathway towards an enhanced and even posthuman future. This article seeks to investigate several ethical themes and wider questions of enhancement, transhumanism and posthumanism. Four themes of interest are: autonomy, identity, futures, and community. Three larger questions can be asked: will everyone be enhanced? Will we be "human" if we are not, one day, transhuman? Should we be enhanced or not? The article proceeds by concentrating on a widespread and sometimes controversial application: the cochlear implant, an auditory prosthesis implanted into Deaf patients. Cochlear implantation and its reception in both the deaf and hearing communities have a distinctive moral discourse, which can offer surprising insights. The paper begins with several points about the enhancement of human beings, transhumanism's reach beyond the human, and posthuman aspirations. Next it focuses on cochlear implants on two sides. Firstly, a shorter consideration of what technologies may do to humans in a transhumanist world. Secondly, a deeper analysis of cochlear implantation's unique socio-political movement, its ethical explanations and cultural experiences linked with pediatric cochlear implantation-and how those wary of being thrust towards posthumanism could marshal such ideas by analogy. As transhumanism approaches, the issues and questions merit continuing intense analysis.

  9. Single and multiple microphone noise reduction strategies in cochlear implants.

    Science.gov (United States)

    Kokkinakis, Kostas; Azimi, Behnam; Hu, Yi; Friedland, David R

    2012-06-01

    To restore hearing sensation, cochlear implants deliver electrical pulses to the auditory nerve by relying on sophisticated signal processing algorithms that convert acoustic inputs to electrical stimuli. Although individuals fitted with cochlear implants perform well in quiet, in the presence of background noise, the speech intelligibility of cochlear implant listeners is more susceptible to background noise than that of normal hearing listeners. Traditionally, to increase performance in noise, single-microphone noise reduction strategies have been used. More recently, a number of approaches have suggested that speech intelligibility in noise can be improved further by making use of two or more microphones, instead. Processing strategies based on multiple microphones can better exploit the spatial diversity of speech and noise because such strategies rely mostly on spatial information about the relative position of competing sound sources. In this article, we identify and elucidate the most significant theoretical aspects that underpin single- and multi-microphone noise reduction strategies for cochlear implants. More analytically, we focus on strategies of both types that have been shown to be promising for use in current-generation implant devices. We present data from past and more recent studies, and furthermore we outline the direction that future research in the area of noise reduction for cochlear implants could follow.

  10. Hyperbaric oxygen upregulates cochlear constitutive nitric oxide synthase

    Directory of Open Access Journals (Sweden)

    Kao Ming-Ching

    2011-02-01

    Full Text Available Abstract Background Hyperbaric oxygen therapy (HBOT is a known adjuvant for treating ischemia-related inner ear diseases. Controversies still exist in the role of HBOT in cochlear diseases. Few studies to date have investigated the cellular changes that occur in inner ears after HBOT. Nitric oxide, which is synthesized by nitric oxide synthase (NOS, is an important signaling molecule in cochlear physiology and pathology. Here we investigated the effects of hyperbaric oxygen on eardrum morphology, cochlear function and expression of NOS isoforms in cochlear substructures after repetitive HBOT in guinea pigs. Results Minor changes in the eardrum were observed after repetitive HBOT, which did not result in a significant hearing threshold shift by tone burst auditory brainstem responses. A differential effect of HBOT on the expression of NOS isoforms was identified. Upregulation of constitutive NOS (nNOS and eNOS was found in the substructures of the cochlea after HBOT, but inducible NOS was not found in normal or HBOT animals, as shown by immunohistochemistry. There was no obvious DNA fragmentation present in this HBOT animal model. Conclusions The present evidence indicates that the customary HBOT protocol may increase constitutive NOS expression but such upregulation did not cause cell death in the treated cochlea. The cochlear morphology and auditory function are consequently not changed through the protocol.

  11. Minimal incision access for pediatric and adult cochlear implantation

    Institute of Scientific and Technical Information of China (English)

    Cui Danmo; Shi Ying; Su Qiaotong; Liu Ting; Han Demin; Li Yongxin

    2014-01-01

    Background Cochlear implant surgery is widely practiced.Minimal incision cochlear implant surgery has been developed with the aims of reducing the impact of surgery on the patient and improving cosmesis while maintaining the low morbidity of conventional wider access approaches.This study aimed to assess the surgical technique and complication rate of minimal incision cochlear implantation (MICI) for children and adults.Methods Data for this study were obtained via a retrospective analysis.Totally 378 patients were included in the study.All patients received minimal incision cochlear implantation,using the skin protector during the process of the operation.The surgical complications of MICI were recorded in a spreadsheet format.The incidence of major and minor complication were analyzed,and appropriate treatment was provided.Results A total of 40 (10.5%) complications were noted in the study.There were 0 life-threatening,9 major,and 31 minor complications.Of the nine major complications,five were device failures,one developed infection and extrusion,and three required receiver-stimulator repositioning.Conclusions MICI is as safe as standard cochlear implantation (SCI) and affords with it other benefits.Eliminating the scalp flap avoids devascularization and minimizes the opportunity of flap infection or necrosis.Complications not related to the flap are similar to SCI.

  12. EFFECTS OF DIABETES ON HEARING AND COCHLEAR STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    LI Xipeng; LI Ruiyu; LI Meng; ZHANG Yanzhuo; GUO Kaosan; WU Liping

    2013-01-01

    Diabetes mellitus (DM) is a chronic systemic disease characterized by hyperglycemia, with various patho-genic mechanisms. From absolute or relative insulin deficiency, patients with DM often demonstrate vari-ous levels of metabolic disorders. Major clinical manifestations of DM include metabolic disorders, vascu-lar lesions, circulatory disturbances and neurologic complications. Along with advances in DM research, re-ports of DM related tinnitus and hearing impairment have increased continuously. Research on DM related auditory system dysfunction has focused on cochlear microcirculation, cellular homeostasis, genetics and ag-ing. Cochlear microcirculation plays an important role in cochlear physiology and its disorders are associat-ed with many inner ear diseases. Ischemia and subsequent reperfusion seen in cochlear microcirculation dis-orders are important factors in hearing damage. Understanding cochlear microcirculation and structural as well as functional changes in DM patients with hearing loss and their causal factors will help reveal patho-genic mechanisms in diabetic hearing loss and provide new ideas in developing interventions and preventing damages caused by diabetes.

  13. Development of Experimental Myopia in Chicks in a Natural Environment

    Science.gov (United States)

    Stone, Richard A.; Cohen, Yuval; McGlinn, Alice M.; Davison, Sherrill; Casavant, Susan; Shaffer, James; Khurana, Tejvir S.; Pardue, Machelle T.; Iuvone, P. Michael

    2016-01-01

    Purpose The hypothesis that outdoor exposure might protect against myopia has generated much interest, although available data find only modest clinical efficacy. We tested the effect of outdoor rearing on form-deprivation myopia in chicks, a myopia model markedly inhibited by high-intensity indoor laboratory lighting. Methods Unilaterally goggled cohorts of White Leghorn chicks were maintained in a species-appropriate, outdoor rural setting during daylight hours to the extent permitted by weather. Control chicks were reared indoors with incandescent lighting. Besides ocular refraction and ultrasound, we determined dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content in retina and vitreous and measured mRNA expression levels of selected clock and circadian rhythm-related genes in the retina/RPE. Results Myopia developed in the goggled eyes of all cohorts. Whereas outdoor rearing lessened myopia by 44% at 4 days, a protective effect was no longer evident at 11 days. Outdoor rearing had no consistent effect on retinal or vitreous content of dopamine or DOPAC. Conforming to prior data on form-deprivation myopia, retina and vitreous levels of DOPAC were reduced in goggled eyes. Compared with contralateral eyes, the retinal expression of clock and circadian rhythm-related genes was modestly altered in myopic eyes of chicks reared indoors or outdoors. Conclusions Outdoor rearing of chicks induces only a partial decrease of goggle-induced myopia that is not maintained, without evidence that retinal dopamine metabolism accounts for the partial myopia inhibition under these outdoor conditions. Although modest, alterations in retinal gene expression suggest that studying circadian signals might be informative for understanding refractive mechanisms. PMID:27618415

  14. Study of hair surface energy and conditioning.

    Science.gov (United States)

    Gao, Timothy; He, Yingxia; Landa, Peter; Tien, Jung-Mei

    2011-01-01

    A new test method has been developed to determine surface energy of hair fibers through measurements of contact angles at two hair/liquid interfaces. By measuring changes in surface energy of the same hair fiber before and after a cosmetic treatment, effects of active ingredients and the performance of tested formulations can be evaluated.The establishment of the method is based on Fowkes theory (1,2) described with two components, a dispersive and a non-dispersive component. The non-polar liquid used in this study was diiodomethane, and the polar liquid was benzyl alcohol. A Kruss 100 Tensiometer was used to measure contact angles of hair fibers. Virgin dark brown and regular bleached hairs were treated with selected conditioner formulations. Reductions in combing forces of hair tresses before and after respective treatments were correlated with decreases in average surface energy of hair fibers obtained from the corresponding tresses.Experimental results indicate that the average surface energy of hair fibers treated with conditioners decreases and the hydrophobicity of the hair surface increases, the results correlate well with the reduction in combing forces after respective treatments. This research work provides a new methodology to evaluate/screen conditioning performance of hair care ingredients and formulations for development of better products.

  15. Biologic rhythms derived from Siberian mammoths' hairs.

    Directory of Open Access Journals (Sweden)

    Mike Spilde

    Full Text Available Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was ∼31 cms/year and ∼16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios, which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna.

  16. Hair transplantation: Standard guidelines of care

    Directory of Open Access Journals (Sweden)

    Patwardhan Narendra

    2008-03-01

    Full Text Available Hair transplantation is a surgical method of hair restoration. Physician qualification : The physician performing hair transplantation should have completed post graduation training in dermatology; he should have adequate background training in dermatosurgery at a centre that provides education training in cutaneous surgery. In addition, he should obtain specific hair transplantation training or experience at the surgical table(hands on under the supervision of an appropriately trained and experienced hair transplant surgeon. In addition to the surgical technique, training should include instruction in local anesthesia and emergency resuscitation and care. Facility : Hair transplantation can be performed safely in an outpatient day case dermatosurgical facility. The day case theatre should be equipped with facilities for monitoring and handling emergencies. A plan for handling emergencies should be in place and all nursing staff should be familiar with the emergency plan. It is preferable, but not mandatory to have a standby anesthetist. Indication for hair transplantation is pattern hair loss in males and also in females. In female pattern hair loss, investigations to rule out any underlying cause for hair loss such as anemia and thyroid deficiency should be carried out. Hair transplantation can also be performed in selected cases of scarring alopecia, eyebrows and eye lashes, by experienced surgeons. Preoperative counseling and informed consent :Detailed consent form listing details about the procedure and possible complications should be signed by the patient. The consent form should specifically state the limitations of the procedure and if more procedures are needed for proper results, it should be clearly mentioned. Patient should be provided with adequate opportunity to seek information through brochures, computer presentations, and personal discussions. Need for concomitant medical therapy should be emphasized. Patients should understand

  17. Promotion of noise-induced cochlear injury by toluene and ethylbenzene in the rat.

    Science.gov (United States)

    Fechter, Laurence D; Gearhart, Caroline; Fulton, Sherry; Campbell, Jerry; Fisher, Jeffrey; Na, Kwangsam; Cocker, David; Nelson-Miller, Alisa; Moon, Patrick; Pouyatos, Benoit

    2007-08-01

    Ethylbenzene + toluene are known individually to have ototoxic potential at high exposure levels and with prolonged exposure times generally of 4-16 weeks. Both ethylbenzene + toluene are minor constituents of JP-8 jet fuel; this fuel has recently been determined to promote susceptibility to noise-induced hearing loss. Therefore, the current study evaluates the ototoxic potential of combined exposure to ethylbenzene + toluene exposure in a ratio calculated from the average found in three laboratories. Rats received ethylbenzene + toluene by inhalation and half of them were subjected simultaneously to an octave band of noise (OBN) of 93-95 dB. Another group received only the noise exposure which was designed to produce a small, but permanent auditory impairment while an unexposed control group was also included. In two separate experiments, exposures occurred either repeatedly on 5 successive days for 1 week or for 5 days on 2 successive weeks to 4000 mg/m(3) total hydrocarbons for 6 h based upon initial pilot studies. The concentration of toluene was 400 ppm and the concentration of ethylbenzene was 660 ppm. Impairments in auditory function were assessed using distortion product otoacoustic emissions and compound action potential testing. Following completion of these tests, the organs of Corti were dissected to permit evaluation of hair cell loss. The uptake and elimination of the solvents was assessed by harvesting key organs at two time points following ethylbenzene + toluene exposure from additional rats not used for auditory testing. Similarly, glutathione (GSH) levels were measured in light of suggestions that oxidative stress might result from solvent-noise exposures. Ethylbenzene + toluene exposure by itself at 4000 mg/m(3) for 6 h did not impair cochlear function or yield a loss of hair cells. However, when combined with a 93-dB OBN exposure combined solvent + noise did yield a loss in auditory function and a clear potentiation of outer hair cell death

  18. The coupling of acetylcholine-induced BK channel and calcium channel in guinea pig saccular type II vestibular hair cells.

    Science.gov (United States)

    Kong, Wei-Jia; Guo, Chang-Kai; Zhang, Xiao-Wen; Chen, Xiong; Zhang, Song; Li, Guan-Qiao; Li, Zhi-Wang; Van Cauwenberge, Paul

    2007-01-19

    Molecular biological studies and electrophysiological data have demonstrated that acetylcholine (ACh) is the principal cochlear and vestibular efferent neurotransmitter among mammalians. However, the functional roles of ACh in type II vestibular hair cells (VHCs II) among mammalians are still unclear, with the exception of the well-known alpha9-containing nicotinic ACh receptor (alpha9-containing nAChR)-activated small conductance, calcium-dependent potassium current (SK) in cochlear hair cells and frog saccular hair cells. The activation of SK current was necessary for the calcium influx through the alpha9-containing nAChR. Recently, we have demonstrated that ACh-induced big conductance, calcium-dependent potassium current (BK) was present in VHCs II of the vestibular end-organ of guinea pig. In this study, the nature of calcium influx for the activation of ACh-induced BK current in saccular VHCs II of guinea pig was investigated. Following extracellular perfusion of ACh, saccular VHCs II displayed a sustained outward current, which was sensitive to iberiotoxin (IBTX). High concentration of apamin failed to inhibit the current amplitude of ACh-induced outward current. Intracellular application of Cs(+) completely abolished the current evoked by ACh. ACh-induced current was potently inhibited by nifedipine, nimodipine, Cd(2+) and Ni(2+), respectively. The inhibition potency of these four calcium channel antagonists was nimodipine>nifedipine>cadmium>nickel. The L-type Ca(2+) channels agonist, (-)-Bay-K 8644 mimicked the effect of ACh and activated an IBTX-sensitive current. In addition, partial VHCs II displayed a biphasic waveform. In conclusion, the present data showed that in the guinea pig saccular VHCs II, ACh-induced BK channel was coupled with the calcium channel, but not the receptor. The perfusion of ACh will drive the opening of calcium channels; the influx of calcium ions will then activate the BK current.

  19. Hair shaft abnormalities--clues to diagnosis and treatment.

    Science.gov (United States)

    Itin, Peter H; Fistarol, Susanna K

    2005-01-01

    Hair dysplasias are congenital or acquired alterations which often involve the hair shaft. Hair shaft abnormalities are characterized by changes in color, density, length and structure. Hair shaft alterations often result from structural changes within the hair fibers and cuticles which may lead to brittle and uncombable hair. The hair of patients with hair shaft diseases feels dry and looks lusterless. Hair shaft diseases may occur as localized or generalized disorders. Genetic predisposition or exogenous factors produce and maintain hair shaft abnormalities. Hair shaft diseases are separated into those with and those without increased hair fragility. In general, optic microscopy and polarized light microscopy of hair shafts provide important clues to the diagnosis of isolated hair shaft abnormalities or complex syndromes. To establish an exact diagnosis of dysplastic hair shafts, a structured history and physical examination of the whole patient are needed which emphasizes other skin appendages such as the nails, sweat and sebaceous glands. Profound knowledge on hair biology and embryology is necessary to understand the different symptom complexes. Therapy of hair shaft disorders should focus on the cause. In addition, minimizing traumatic influences to hair shafts, such as drying hair with an electric dryer or permanent waves and dyes, is important. A short hairstyle is more suitable for patients with hair shaft disorders.

  20. Effects of chronic furosemide on central neural hyperactivity and cochlear thresholds after cochlear trauma in guinea pig

    Directory of Open Access Journals (Sweden)

    Wilhelmina eMulders

    2014-08-01

    Full Text Available Increased neuronal spontaneous firing rates have been observed throughout the central auditory system after trauma to the cochlea and this hyperactivity is believed to be associated with the phantom perception of tinnitus. Previously we have shown in an animal model of hearing loss, that an acute injection with furosemide can significantly decrease hyperactivity after cochlear trauma and eliminate behavioural evidence of tinnitus of early onset. However, furosemide also has the potential to affect cochlear thresholds. In this paper we measured the effects of a chronic (daily injections for 7 days furosemide treatment on the spontaneous firing rate of inferior colliculus neurons and on cochlear thresholds in order to establish whether a beneficial effect on hyperactivity can be obtained without causing additional hearing loss. Guinea pigs were exposed to a 10 kHz, 124dB, 2 hour acoustic trauma, and after 5 days of recovery, were given daily i.p. injections of 80mg/kg furosemide or an equivalent amount of saline. The activity of single IC neurons was recorded 24 hours following the last injection. The furosemide treatment had no effect on cochlear thresholds compared to saline injections but did result in significant reductions in spontaneous firing rates recorded in inferior colliculus. These results that suggest a long term beneficial effect of furosemide on hyperactivity after cochlear trauma may be achievable without detrimental effects on hearing, which is important when considering therapeutic potential.

  1. Cochlear implant electrode array misplaced in Hyrtl's fissure.

    Science.gov (United States)

    Mouzali, Amina; Ouennoughi, Kheiredidine; Haraoubia, Mohamed-Salah; Zemirli, Omar; Triglia, Jean Michel

    2011-11-01

    Hyrtl's fissure is a cleft that is present in the developing fetal petrous temporal bone and extends from the area inferior to the round window to the meninges of the posterior fossa. Persistent Hyrtl's fissure, due to incomplete ossification, is considered a rare temporal bone malformation, and is a known cause of perilabyrinthine cerebrospinal fluid fistula. Very few cases are reported as being at risk of complication of cochlear implant surgery. Here we report the case of an 8-year-old boy with misplacement of an electrode array in Hyrtl's fissure. The diagnosis was made postoperatively, since cochlear implant failure was suspected from non-auditory responses. Computed tomography (CT) revealed the extracochlear location of the electrode array. We emphasize the role of presurgical imaging CT and magnetic resonance imaging in detecting temporal bone abnormalities, and we discuss the value of intraoperative auditory nerve response telemetry and postoperative radiological evaluation in diagnosing cochlear implant misplacement.

  2. Pre-, intra- and post-operative imaging of cochlear implants

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.J.; Naguib, N.N.N.; Burck, I. [University Hospital Frankfurt (Germany). Inst. of Diagnostic and Interventional Radiology; Tawfik, A. [Mansoura Univ. (Egypt). Dept. of Diagnostic and Interventional Radiology; Emam, A. [University Hospital Alexandria (Egypt). Dept. of Diagnostic and Interventional Radiology; Nour-Eldin, A. [University Hospital Cairo (Egypt). Dept. of Radiology; Stoever, T. [University Hospital of Frankfurt (Germany). Dept. of Otolaryngology

    2015-11-15

    The purpose of this review is to present essential imaging aspects in patients who are candidates for a possible cochlear implant as well as in postsurgical follow-up. Imaging plays a major role in providing information on preinterventional topography, variations and possible infections. Preoperative imaging using DVT, CT, MRI or CT and MRI together is essential for candidate selection, planning of surgical approach and exclusion of contraindications like the complete absence of the cochlea or cochlear nerve, or infection. Relative contraindications are variations of the cochlea and vestibulum. Intraoperative imaging can be performed by fluoroscopy, mobile radiography or DVT. Postoperative imaging is regularly performed by conventional X-ray, DVT, or CT. In summary, radiological imaging has its essential role in the pre- and post-interventional period for patients who are candidates for cochlear implants.

  3. Temporal feature perception in cochlear implant users.

    Directory of Open Access Journals (Sweden)

    Lydia Timm

    Full Text Available For the perception of timbre of a musical instrument, the attack time is known to hold crucial information. The first 50 to 150 ms of sound onset reflect the excitation mechanism, which generates the sound. Since auditory processing and music perception in particular are known to be hampered in cochlear implant (CI users, we conducted an electroencephalography (EEG study with an oddball paradigm to evaluate the processing of small differences in musical sound onset. The first 60 ms of a cornet sound were manipulated in order to examine whether these differences are detected by CI users and normal-hearing controls (NH controls, as revealed by auditory evoked potentials (AEPs. Our analysis focused on the N1 as an exogenous component known to reflect physical stimuli properties as well as on the P2 and the Mismatch Negativity (MMN. Our results revealed different N1 latencies as well as P2 amplitudes and latencies for the onset manipulations in both groups. An MMN could be elicited only in the NH control group. Together with additional findings that suggest an impact of musical training on CI users' AEPs, our findings support the view that impaired timbre perception in CI users is at partly due to altered sound onset feature detection.

  4. Modeling Sound Processing in Cochlear Nuclei

    Science.gov (United States)

    Meddis, Ray

    2003-03-01

    The cochlear nucleus is an obligatory relay nucleus between the ear and the rest of the brain. It consists of many different types of neurons each responding differently to the same stimulus. Much is known about the wiring diagram of the system but it has so far proved difficult to characterise the signal processing that is going on or what purpose it serves. The solution to this problem is a pre-requisite of any attempt to produce a practical electronic simulation that exploits the brain's unique capacity to recognise the significance of acoustic events and generate appropriate responses. This talk will explain the different types of neural cell and specify hypotheses as to their various functions. Cell-types vary in terms of their size and shape as well as the number and type of minute electrical currents that flow across the cell membranes. Computer models will also be used to illustrate how the physical substrate (the wet-ware) is used to achieve its signal-processing goals.

  5. Half-flat Quantum Hair

    CERN Document Server

    García-Compeán, Hugo; Martínez-Merino, Aldo; Santos-Silva, Roberto

    2013-01-01

    By wrapping D3-branes over 3-cycles on a Half-flat manifold we construct an effective supersymmetric Black Hole in the N=2 low-energy theory in four-dimensions. Specifically we find that the torsion cycles present in a half-flat compactification, corresponding to the mirror symmetric image of electric NS flux on a Calabi-Yau manifold, manifest in the black hole physics as quantum hair. We compute the electric and magnetic charges related to the quantum hair, and also the mass contribution to the effective black hole. We find that by wrapping a number of D3-branes equal to the order of the discrete group associated to the torsional part of the half-flat homology, the effective charge and mass terms vanishes. We compute the variation of entropy and the corresponding temperature associated with the lost of the quantum hair. We also comment on the equivalence between canceling Freed-Witten anomalies and the assumption of self-duality for the five-form field strength. Finally from a K-theoretical perspective, we c...

  6. Black Holes with Skyrme Hair

    CERN Document Server

    Shiiki, N; Shiiki, Noriko; Sawado, Nobuyuki

    2005-01-01

    This paper is intended to give a review of the recent developments on black holes with Skyrme hair. The Einstein-Skyrme system is known to possess black hole solutions with Skyrme hair. The spherically symmetric black hole skyrmion with B=1 was the first discovered counter example of the no-hair conjecture for black holes. Recently we found the B=2 axially symmetric black hole skyrmion. In this system, the black hole at the center of the skyrmion absorbs the baryon number partially, leaving fractional charge outside the horizon. Therefore the baryon number is no longer conserved. We examine the B=1, 2 black hole solutions in detail in this paper. The model has a natural extension to the gauged version which can describe monopole black hole skyrmions. Callan and Witten discussed the monopole catalysis of proton decay within the Skyrme model. We apply the idea to the Einstein-Maxwell-Skyrme system and obtain monopole black hole skyrmions. Remarkably there exist multi-black hole skyrmion solutions in which the g...

  7. Factors contributing to communication skills development in cochlear implanted children

    Directory of Open Access Journals (Sweden)

    Ostojić Sanja

    2015-01-01

    Full Text Available Background/Aim. Over the last 10 years more than 300 persons received cochlear implant in Serbia and more than 90% of the recipients were children under 10 years of age. The program of cochlear implantation includes postoperative rehabilitation in which cognitive, integrative and developmental methods are used. The study was conducted to reveal factors affecting communication performance (CP of cochlear implanted (CI children. Special attention was focused on the influence of the duration and intensity of rehabilitation and hearing age on further development of communication skills. Methods. A group of 30 CI children (13 boys and 17 girls aged 2 to 5 years was enrolled in the study. All of the children had average intelligence and no other developmental disorder. They lived in families and attended rehabilitative seances 3 to 5 times a week. Their parents/ caregivers answered structured questionnaire about functioning after pediatric cochlear implantation (FAPCI and the results were the subject of detailed statistical analysis. Results. Analysis of variance did not show any difference between the boys and the girls regarding FAPCI achievements (F (1, 28 = 2.909; p = 0.099 and age aberration in CP score (F (1, 28 = 0.114, p = 0.738. Correlation analysis showed a statistically significant difference in FAPCI scores related to hearing age and duration of rehabilitation. Regression analysis (enter method showed that model consisting of indipendent variables significantly contributed to prediction of overall FAPCI scores and Adjusted R2 value could explain 32% difference in communication skills of participants in this study. Conclusion. Communication skills of CI children evaluated by FAPCI are falling behind normatives for normal hearing children 18.6 months on the average. Hearing age, duration and intensity of rehabilitation have positive predictive value for communication skills development. Later identification of hearing loss and later cochlear

  8. Ion beam microanalysis of human hair follicles

    Science.gov (United States)

    Kertész, Zs.; Szikszai, Z.; Pelicon, P.; Simčič, J.; Telek, A.; Bíró, T.

    2007-07-01

    Hair follicle is an appendage organ of the skin which is of importance to the survival of mammals and still maintains significance for the human race - not just biologically, but also through cosmetic and commercial considerations. However data on composition of hair follicles are scarce and mostly limited to the hair shaft. In this study we provide detailed information on the elemental distribution in human hair follicles in different growth phases (anagen and catagen) using a scanning proton microprobe. The analysis of skin samples obtained from human adults undergoing plastic surgery and of organ-cultured human hair follicles may yield a new insight into the function, development and cyclic activity of the hair follicle.

  9. LSD in pubic hair in a fatality.

    Science.gov (United States)

    Gaulier, Jean-michel; Maublanc, Julie; Lamballais, Florence; Bargel, Sophie; Lachâtre, Gérard

    2012-05-10

    Lysergic acid diethylamide (LSD) is a potent hallucinogen, active at very low dosage and its determination in body fluids in a forensic context may present some difficulties, even more so in hair. A dedicated liquid chromatography-electrospray-tandem mass spectrometry (LC-ES-MS/MS) assay in hair was used to document the case of a 24-year-old man found dead after a party. Briefly, after a decontamination step, a 50mg sample of the victim's pubic hair was cut into small pieces (LSD. A LSD concentration of 0.66pg/mg of pubic hair was observed. However, this result remains difficult to interpret owing to the concomitant LSD presence in the victim's post mortem blood and urine, the lack of previously reported LSD concentrations in hair, and the absence of data about LSD incorporation and stability in pubic hair.

  10. Ion beam microanalysis of human hair follicles

    Energy Technology Data Exchange (ETDEWEB)

    Kertesz, Zs. [Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen, P.O. Box 51 (Hungary)]. E-mail: zsofi@atomki.hu; Szikszai, Z. [Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen, P.O. Box 51 (Hungary); Pelicon, P. [Jozef Stefan Institute, Jamova 39, P.O. Box 3000, Ljubljana (Slovenia); Simcic, J. [Jozef Stefan Institute, Jamova 39, P.O. Box 3000, Ljubljana (Slovenia); Telek, A. [Department of Physiology and Cell Physiology Research Group of the Hungarian Academy of Sciences, University of Debrecen, Medical and Health Science Center, Research Center for Molecular Medicine, H-4012, Debrecen, Nagyerdei krt. 98 (Hungary); Biro, T. [Department of Physiology and Cell Physiology Research Group of the Hungarian Academy of Sciences, University of Debrecen, Medical and Health Science Center, Research Center for Molecular Medicine, H-4012, Debrecen, Nagyerdei krt. 98 (Hungary)

    2007-07-15

    Hair follicle is an appendage organ of the skin which is of importance to the survival of mammals and still maintains significance for the human race - not just biologically, but also through cosmetic and commercial considerations. However data on composition of hair follicles are scarce and mostly limited to the hair shaft. In this study we provide detailed information on the elemental distribution in human hair follicles in different growth phases (anagen and catagen) using a scanning proton microprobe. The analysis of skin samples obtained from human adults undergoing plastic surgery and of organ-cultured human hair follicles may yield a new insight into the function, development and cyclic activity of the hair follicle.

  11. Red Ginseng Extract Promotes the Hair Growth in Cultured Human Hair Follicles

    OpenAIRE

    Park, Gyeong-Hun; Park, Ki-young; Cho, Hong-il; Lee, Sang-Min; Han, Ji Su; Won, Chong Hyun; Chang, Sung Eun; Lee, Mi Woo; Choi, Jee Ho; Moon, Kee Chan; Shin, Hyoseung; KANG, YONG JUNG; Lee, Dong Hun

    2015-01-01

    Ginseng has been shown to promote hair growth in several recent studies. However, its effects on human hair follicles and its mechanisms of action have not been sufficiently elucidated. This study aimed to investigate the hair growth-promoting effects of red ginseng extract (RGE) and its ginsenosides. The proliferative activities of cultured human hair follicles treated with RGE and ginsenoside-Rb1 were assessed using Ki-67 immunostaining. Their effects on isolated human dermal papilla cells ...

  12. Analysis of Speech Processing Strategies in Cochlear Implants

    Directory of Open Access Journals (Sweden)

    Kouachi Rouiha

    2008-01-01

    Full Text Available Cochlear implants can restore partial hearing to profoundly deaf people; the main function of these prostheses is to electrically stimulate the auditory nerve using an electrode array inserted in the cochlea. The acoustic signal is picked up by a microphone and analyzed. Then the extracted parameters of the signal are coded to generate electrical signals reconstituting the original signal. Currently all commercialized implants are multichannel they allow to stimulate the auditory nerve at different place of the cochlea, exploiting the tonotopic coding of the frequencies. This research will present an overview of various signal processing techniques that have been used for cochlear prosthesis over the years.

  13. Cochlear implant challenges encountered in tuberculous otitis media

    Institute of Scientific and Technical Information of China (English)

    Cheng-Fang Chen; Zhao-Hui Liu; Jing Xie; Xiao-Bo Ma; Yi Li; Shu-Sheng Gong

    2012-01-01

    ABSTRACT Tuberculous otitis media (TOM) is rare inENT department, and is frequently misdiagnosed as otitis media. Thus early systemic treatment is very important forTOM. We reported a case report withTOM to highlight development of the disease and difficulties in clinical treatment in late stage ofTOM. Implantation of ossified and eroded cochlea poses many unique challenges to both the surgeon and programming team. With thorough preparation and complete knowledge about characters of specific issues, implantation would be performed successfully, and patients with ossified cochlear could benefit from cochlear implantation.

  14. Staphylococcus lugdunensis: novel organism causing cochlear implant infection

    Directory of Open Access Journals (Sweden)

    Samina Bhumbra

    2014-06-01

    Full Text Available A majority of cochlear implant infections are caused by Staphylococcus aureus or Pseudomonas aeruginosa. Reported here is a pediatric patient with a cochlear implant infection caused by methicillin-resistant Staphylococcus lugdunensis, a coagulase-negative Staphylococcus that has only recently been determined to be clinically relevant (1988. Unlike other coagulase-negative Staphylococcus, it is more aggressive, carrying a greater potential for tissue destruction. In pediatrics, the organism is uncommon, poorly described, and generally pan-susceptible. Described herein is the presentation and management of this unusual organism in a pediatric setting.

  15. Repigmentation of hair following adalimumab therapy

    OpenAIRE

    Tintle, Suzanne J; Dabade, Tushar S; Kalish, Robert A; Rosmarin, David M.

    2015-01-01

    Repigmentation of canities, or age-related grey or white hair, is a rare occurrence. Generalized repigmentation of grey-white hair has been reported following inflammatory processes,[1] and heterochromia (localized patches of hair repigmentation) is even more unusual, reported in association with medication use and malignancy.Tumor necrosis factor (TNF) inhibitors are increasingly utilized medications for inflammatory disorders, including psoriasis, rheumatoid arthritis, and inflammatory bowe...

  16. ESTROGEN RECEPTORS OF HAIRS BLACKS AND WHITES

    Directory of Open Access Journals (Sweden)

    H. Laswati

    2014-12-01

    Full Text Available Background: Aging is termed as same as degenerative process, in which all part of tissue organs retarted the microstructure either macrostructure, forming and function even the colour, including black hair change to white hair. Several researchers have been recommended that estrogen hormone be able ease black to white hair, but hormone without any presenting of receptor won’t be work properly. The main aim of this study were to determine amount of estrogen receptor contents in famales and males black and white hairs included the microscopically structure. Method: Twelve females and males there were 50 -56 years old each pairs black and white head hairs were plucked along with follicles. This estrogen receptors analyzed using radioreceptor binding assay there were 5mm eah hair follices including the root cutted and each pair put its in 2 ml glass tube already filled in with 500 µl 125I-estradiol and incubated in 37oC for 3 hrs. Following times were over the tube flushed twice carefully the hair won’t be flushed. Then count by putting in the gamma counter chamber for 1 minute each. The values that shown in the monitor as CPM (count per minute, recorded as receptor of estradiol. Results: Mean (±SD sum estrogen receptor in females black and white hairs were 479.3 ± 37.5 and 387.7 ± 33.0, but significantly decreased in male black hair was 316.9±17.8 and 274.0 ± 19.8. All those pairs significantly different either female black and white hairs or male black and white hair and also significantly different among groups. Conclusion: The lowest estrogen receptors recorded in male white hairs and microstructure decreasing of melanin contents.

  17. Hair dye poisoning and the developing world

    Directory of Open Access Journals (Sweden)

    Sampathkumar Krishnaswamy

    2009-01-01

    Full Text Available Hair dye poisoning has been emerging as one of the important causes of intentional self harm in the developing world. Hair dyes contain paraphenylene-diamine and a host of other chemicals that can cause rhabdomyolysis, laryngeal edema, severe metabolic acidosis and acute renal failure. Intervention at the right time has been shown to improve the outcome. In this article, we review the various manifestations, clinical features and treatment modalities for hair dye poisoning.

  18. Hair Testing for Drugs of Abuse

    OpenAIRE

    Karačić, Višnja; Skender, Ljiljana

    2003-01-01

    Hair testing for drugs of abuse is a developing technology, which offers the possibility of longer detection times than is commonly obtained with urine analysis. It is the main method for evaluation of an individual’s drugs of abuse history. In many countries hair analysis is routinely used to detect drug abuse in forensic cases, occupational and traffic medicine and clinical toxicology. Hair analysis in pregnant women, neonates and infants is a useful tool for the detection of...

  19. Aspects of Music with Cochlear Implants – Music Listening Habits and Appreciation in Danish Cochlear Implant Users

    DEFF Research Database (Denmark)

    Petersen, Bjørn; Hansen, Mads; Sørensen, Stine Derdau

    Cochlear implant users differ significantly from their normal hearing peers when it comes to perception of music. Several studies have shown that structural features – such as rhythm, timbre, and pitch – are transmitted less accurately through an implant. However, we cannot predict personal...... enjoyment of music solely as a function of accuracy of perception. But can music be pleasant with a cochlear implant at all? Our aim here was to gather information of both music enjoyment and listening habits before the onset of hearing loss and post-operation from a large, representative sample of Danish...... recipients. A hundred and sixty three adult cochlear implant users (101 females, 62 males) completed a survey containing questions about musical background, listening habits, and music enjoyment. The results indicate a wide range of success with music, but in general, the results show that the CI users enjoy...

  20. Beam shaping for cosmetic hair removal

    Science.gov (United States)

    Lizotte, Todd E.; Tuttle, Tracie

    2007-09-01

    Beam shaping has the potential to provide comfort to people who require or seek laser based cosmetic skin procedures. Of immediate interest is the procedure of aesthetic hair removal. Hair removal is performed using a variety of wavelengths from 480 to 1200 nm by means of filtered Xenon flash lamps (pulsed light) or 810 nm diode lasers. These wavelengths are considered the most efficient means available for hair removal applications, but current systems use simple reflector designs and plane filter windows to direct the light to the surface being exposed. Laser hair removal is achieved when these wavelengths at sufficient energy levels are applied to the epidermis. The laser energy is absorbed by the melanin (pigment) in the hair and hair follicle which in turn is transformed into heat. This heat creates the coagulation process, which causes the removal of the hair and prevents growth of new hair [1]. This paper outlines a technique of beam shaping that can be applied to a non-contact based hair removal system. Several features of the beam shaping technique including beam uniformity and heat dispersion across its operational treatment area will be analyzed. A beam shaper design and its fundamental testing will be discussed in detail.

  1. Hybrid fur rendering: combining volumetric fur with explicit hair strands

    DEFF Research Database (Denmark)

    Andersen, Tobias Grønbeck; Falster, Viggo; Frisvad, Jeppe Revall

    2016-01-01

    Hair is typically modeled and rendered using either explicitly defined hair strand geometry or a volume texture of hair densities. Taken each on their own, these two hair representations have difficulties in the case of animal fur as it consists of very dense and thin undercoat hairs in combination...... with coarse guard hairs. Explicit hair strand geometry is not well-suited for the undercoat hairs, while volume textures are not well-suited for the guard hairs. To efficiently model and render both guard hairs and undercoat hairs, we present a hybrid technique that combines rasterization of explicitly...... defined guard hairs with ray marching of a prismatic shell volume with dynamic resolution. The latter is the key to practical combination of the two techniques, and it also enables a high degree of detail in the undercoat. We demonstrate that our hybrid technique creates a more detailed and soft fur...

  2. Myosin VI is required for the proper maturation and function of inner hair cell ribbon synapses.

    Science.gov (United States)

    Roux, Isabelle; Hosie, Suzanne; Johnson, Stuart L; Bahloul, Amel; Cayet, Nadège; Nouaille, Sylvie; Kros, Corné J; Petit, Christine; Safieddine, Saaid

    2009-12-01

    The ribbon synapses of auditory inner hair cells (IHCs) undergo morphological and electrophysiological transitions during cochlear development. Here we report that myosin VI (Myo6), an actin-based motor protein involved in genetic forms of deafness, is necessary for some of these changes to occur. By using post-embedding immunogold electron microscopy, we showed that Myo6 is present at the IHC synaptic active zone. In Snell's waltzer mutant mice, which lack Myo6, IHC ionic currents and ribbon synapse maturation proceeded normally until at least post-natal day 6. In adult mutant mice, however, the IHCs displayed immature potassium currents and still fired action potentials, as normally only observed in immature IHCs. In addition, the number of ribbons per IHC was reduced by 30%, and 30% of the remaining ribbons were morphologically immature. Ca2+-dependent exocytosis probed by capacitance measurement was markedly reduced despite normal Ca2+ currents and the large proportion of morphologically mature synapses, which suggests additional defects, such as loose Ca2+-exocytosis coupling or inefficient vesicular supply. Finally, we provide evidence that Myo6 and otoferlin, a putative Ca2+ sensor of synaptic exocytosis also involved in a genetic form of deafness, interact at the IHC ribbon synapse, and we suggest that this interaction is involved in the recycling of synaptic vesicles. Our findings thus uncover essential roles for Myo6 at the IHC ribbon synapse, in addition to that proposed in membrane turnover and anchoring at the apical surface of the hair cells.

  3. Assessment of a direct acoustic cochlear stimulator.

    Science.gov (United States)

    Chatzimichalis, Michail; Sim, Jae Hoon; Huber, Alexander M

    2012-01-01

    This study aimed to assess the functional results of a new, active, acoustic-mechanical hearing implant, the Direct Acoustic Cochlear Stimulation Partial Implant (DACS PI), in a preclinical study. The DACS PI is an electromagnetic device fixed to the mastoid by screws and coupled to a standard stapes prosthesis by an artificial incus (AI). The function of the DACS PI-aided reconstruction was assessed by determining: (1) the maximum equivalent sound pressure level (SPL) of the implant, which was obtained from measurements of the volume displacement at the round window in normal and implanted ears, and (2) the quality at the coupling interface between the AI of the DACS and the stapes prosthesis, which was quantified from measurements of relative motions between the AI and the prosthesis. Both measurements were performed with fresh temporal bones using a scanning laser Doppler interferometry system. The expected maximum equivalent SPL with a typical driving voltage of 0.3 V was about 115-125 dB SPL up to 1.5 kHz in reconstruction with the DACS PI, and decreased with a roll-off slope of about 65 dB/decade, reaching 90 dB SPL at 8 kHz. The large roll-off relative to a normal ear was presumed to be a relatively high inductive impedance of the coil of the DACS PI actuator at higher frequencies. Good coupling quality between the AI and the prosthesis was achieved below the resonance (∼1.5 kHz) of the DACS PI for all tested stapes prostheses. Above the resonance, the SMart Piston, which is composed of a shape-memory alloy, had the best coupling quality.

  4. Glutamine synthetase localization in cortisol-induced chick embryo retinas

    OpenAIRE

    1980-01-01

    We report here for the first time, in chick retina, Muller cell localization of glutamine synthetase (GS) activity by an immunohistochemical technique, in agreement with previous reports of glial localization of this enzyme in rat brain and retina. Age- dependent changes in the endogenous enzyme activity as well as cortisol- induced changes in GS activity, both in ovo and in vitro, measured biochemically, reflect the changes observed by staining.

  5. Interactions among dietary boron, molybdenum, and magnesium in the chick

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, C.D.; Nielsen, F.H.

    1986-03-01

    The authors have previously reported that dietary B affects plasma Mo concentrations in chicks fed inadequate levels of Mg and cholecalciferol (vit. D/sub 3/). Because of this finding, they studied the effect of dietary Mo and Mg on the signs of B deficiency in vit. D/sub 3/ deprived chicks. In a fully crossed, 2 x 2 x 2 factorially arranged experiment, day-old cockerel chicks (19 per group) were fed a ground corn-casein-corn oil based diet (containing 0.850 mg B, 0.319 mg Mo, and 125 IU vit. D/sub 3//kg) supplemented with B at 0 or 3 mg/kg, Mo at 0 or 20 mg/kg, and Mg at 300 or 500 mg/kg. After four weeks, B deprivation depressed growth and elevated the plasma glucose and the brain wt/body wt ratio. Low dietary Mo elevated the heart wt/body wt ratio. An interaction between B and Mg affected hemoglobin and plasma alkaline phosphatase and an interaction between B and Mo affected the heart wt/body wt and liver wt/body wt ratios. Mg deficiency gave usual signs including depressed growth, plasma alkaline phosphatase, glucose, and spleen and liver wt/body wt ratios and elevated hematocrit and brain wt/body wt ratio. The findings suggest that physiological levels of Mg and Mo affect B metabolism. The effects of low dietary Mo on vit. D/sub 3/ and/or Mg-deficient chicks needs to be elucidated.

  6. Study on the Prevention of Rabbit Hair from Loss

    Institute of Scientific and Technical Information of China (English)

    刘世春; 张华鹏; 姚穆

    2001-01-01

    A new method is presented to solve the problem of loss of rabbit hair by using ES fiber blending with rabbit hair. ES fiber is used to bond the rabbit hair to prevent the rabbit hair from losing after heat setting. The factors affecting hair loss are heat setting temperature, rabbit hair/ES fiber blend ratio, fabric heating setting, twistsof yarn, etc. Temperature of heat setting and ES fiber content are the two key factors This method has almost no detrimental effect on the coziness of the fabric, which is better than other hair loss prevention methods.

  7. Gipc1 has a dual role in Vangl2 trafficking and hair bundle integrity in the inner ear

    Science.gov (United States)

    Giese, Arnaud P.; Ezan, Jérome; Wang, Lingyan; Lasvaux, Léa; Lembo, Frédérique; Mazzocco, Claire; Richard, Elodie; Reboul, Jérome; Borg, Jean-Paul; Kelley, Matthew W.; Sans, Nathalie; Brigande, John; Montcouquiol, Mireille

    2012-01-01

    Vangl2 is one of the central proteins controlling the establishment of planar cell polarity in multiple tissues of different species. Previous studies suggest that the localization of the Vangl2 protein to specific intracellular microdomains is crucial for its function. However, the molecular mechanisms that control Vangl2 trafficking within a cell are largely unknown. Here, we identify Gipc1 (GAIP C-terminus interacting protein 1) as a new interactor for Vangl2, and we show that a myosin VI-Gipc1 protein complex can regulate Vangl2 traffic in heterologous cells. Furthermore, we show that in the cochlea of MyoVI mutant mice, Vangl2 presence at the membrane is increased, and that a disruption of Gipc1 function in hair cells leads to maturation defects, including defects in hair bundle orientation and integrity. Finally, stimulated emission depletion microscopy and overexpression of GFP-Vangl2 show an enrichment of Vangl2 on the supporting cell side, adjacent to the proximal membrane of hair cells. Altogether, these results indicate a broad role for Gipc1 in the development of both stereociliary bundles and cell polarization, and suggest that the strong asymmetry of Vangl2 observed in early postnatal cochlear epithelium is mostly a ‘tissue’ polarity readout. PMID:22991442

  8. Central administration of neuromedin U suppresses food intake in chicks.

    Science.gov (United States)

    Kamisoyama, Hiroshi; Honda, Kazuhisa; Saneyasu, Takaoki; Sugahara, Kunio; Hasegawa, Shin

    2007-06-08

    The appetite-suppressive action of brain-gut peptides is similar in both chickens and mammals. In mammals, the brain-gut peptide neuromedin U (NMU) suppresses food intake via hypothalamic neuropeptides, corticotropin-releasing factor (CRF), oxytocin, and arginine-vasopressin. In chickens, central administration of CRF, oxytocin, or arginine-vasotocin (AVT, a nonmammalian equivalent of arginine-vasopressin) suppresses food intake. However, the anorexigenic action of NMU in chickens has not yet been identified. In the present study, we analyzed the effects of the central administration of NMU on food intake and hypothalamic mRNA levels of CRF, AVT and mesotocin (a nonmammalian equivalent of oxytocin) in chicks. Intracerebroventricular administration of NMU in chicks significantly suppressed food intake and induced wing-flapping behavior. NMU also significantly upregulated mRNA expression of CRF and AVT, but did not influence mRNA expression of mesotocin in the hypothalamus. These results suggest that NMU functions as an appetite-suppressive peptide via CRF and AVT in the central nervous system in chicks.

  9. Introduction of DT40 cells into chick embryos

    Institute of Scientific and Technical Information of China (English)

    Mariko Toba; Fumio Ebara; Hiroki Furuta; Yuichi Matsushimal; Yasuo Kitagawa; Noboru Fujihara

    2001-01-01

    To examine the transfection of exogenous genes into chick embryos, applying the characteristics of avian leukosis virus (ALV)-induced chicken B cell line DT40 to the production of chimeric birds. Methods: The DT40cells incorporated with exogenous gene (lacZ constructs encoding Escherichia coli β-galactosidase: β-gal) were introduced into chick embryos by the injection of cells into stage X blastoderm. Manipulated eggs were incubated for 3 (trial 1 ) or 6 (trial 2) days, and the expression of lacZ DNA was detected by a histochemical staining method of β-galactosidase and polymerase chain reaction (PCR) analysis. Results: The survival rates of the manipulated embryos incubated for 3 days (stage 18-20: trial 1) and 6 days (stage 28, 30: trial 2) were about 42% and 38%, respectively.The expression rates of the lacZ gene in the embryos in the trials 1 and 2 were about 60% and 23%, respectively, for the survived embryos. Conclusio: The rate of embryonic viability and expression rate of introduced genes were not so high, but it suggested the possibility of utilizing the DT40 cells as a vector for carrying exogenous genes into chick embryos.

  10. [Evaluation of Antilles fish ciguatoxicity by mouse and chick bioassays].

    Science.gov (United States)

    Pottier, I; Vernoux, J P

    2003-03-01

    Ciguatera is a common seafood poisoning in Western Atlantic and French West Indies. Ciguatera fish poisoning in the Caribbean is a public health problem. A toxicological study was carried out on 178 Caribbean fish specimens (26 species) captured off Guadeloupe and Saint Barthelemy between 1993 and 1999. The mouse bioassay and the chick feeding test were used to control fish edibility. Ciguatoxins presence was assumed when symptomatology was typical of ciguatera in mouse and chick. Fishes were classified in three groups: non toxic fish (edible), low toxic fish (not edible) and toxic fish (not edible). 75% of fishes were non toxic. Toxic fish specimens belonged to four families of high trophic level carnivores: Carangidae, Lutjanidae, Serranidae et Sphyraenidae. Percentages of toxic fishes to humans reached 55% for Caranx latus and 33% for Caranx bartholomaei and Caranx lugubris. Only a significant correlation between weight and toxicity was only found for C. latus and snappers. Small carnivorous groupers (Serranidae) were also toxic. Atoxic fish species were (a) pelagic fish (Coryphaena hippurus, Auxis thazard and Euthynnus pelamis), (b) invertebrates feeders (Malacanthus plumieri, Balistes vetula), (c) small high-risk fish or (d) fish of edible benthic fish families. Liver of four fishes (Mycteroperca venenosa, Caranx bartholomaei, Seriola rivoliana, Gymnothorax funebris) contained ciguatoxins at a significant level although their flesh was safe. This study confirms the usefulness of mouse and chick bioassays for sanitary control of fish.

  11. Theory of Mind and Language in Children with Cochlear Implants

    Science.gov (United States)

    Remmel, Ethan; Peters, Kimberly

    2009-01-01

    Thirty children with cochlear implants (CI children), age range 3-12 years, and 30 children with normal hearing (NH children), age range 4-6 years, were tested on theory of mind and language measures. The CI children showed little to no delay on either theory of mind, relative to the NH children, or spoken language, relative to hearing norms. The…

  12. Prelingual deafness: Benefits from cochlear implants versus conventional hearing aids

    Science.gov (United States)

    Bittencourt, Aline Gomes; Torre, Ana Adelina Giantomassi Della; Bento, Ricardo Ferreira; Tsuji, Robinson Koji; Brito, Rubens de

    2012-01-01

    Summary Introduction: The majority of patients with hearing loss, including those with severe hearing loss, benefits from the use of hearing aids. The cochlear implant is believed to achieve better results in a child with hearing loss in cases where the severity of disability renders hearing aids incapable of providing adequate sound information, as they require sufficient cochlear reserve so that acoustic detention occurs. Objective: To assess if cochlear implants provide more benefit than conventional hearing aids in prelingually deaf patients. Summary of the findings: The study was a systematic review of scientific papers selected by a search of the SciELO, Cochrane, MEDLINE, and LILACS-BIREME databases. Among the 2169 articles found, 12 studies proved relevant to the issue and presented an evidence strength rating of B. No publications rated evidence strength A. Seven of the studies analyzed were prospective cohorts and 5 were cross-sectional studies. Conclusion: Based on several studies, cochlear implants were demonstrated to be the best current alternative for bilateral severe or profound hearing loss, achieving better results in speech perception and development in prelingual children when compared to conventional hearing aids. PMID:25991962

  13. Predictors of Spoken Language Development Following Pediatric Cochlear Implantation

    NARCIS (Netherlands)

    Boons, Tinne; Brokx, Jan; Dhooge, Ingeborg; Frijns, Johan; Peeraer, Louis; Vermeulen,; Wouters,; Wieringen, van

    2012-01-01

    Objectives: Although deaf children with cochlear implants (CIs) are able to develop good language skills, the large variability in outcomes remains a significant concern. The first aim of this study was to evaluate language skills in children with CIs to establish benchmarks. The second aim was to m

  14. Mismatch Negativity Based Neurofeedback for Cochlear Implant Users

    NARCIS (Netherlands)

    Luckmann, Annika; Başkent, Deniz; Jolij, Jacob

    2015-01-01

    Cochlear implant (CI) users experience great difficulty when it comes to pitch discrimination. This leads to problems during daily interactions, due to poor speech perception, but also a very low pleasure ratings for music. Improving pitch perception and discrimination in CI users would improve thei

  15. Use of Computed Tomography Scans for Cochlear Implants

    OpenAIRE

    Whiting, Bruce R.; Holden, Timothy A.; Brunsden, Barry S.; Finley, Charles C.; Skinner, Margaret W.

    2007-01-01

    While 3-dimensional (3D) imaging by computed tomography has long been desirable for research and treatment of cochlear-implant patients, technical challenges have limited its wide application. Recent developments in scanner hardware and image processing techniques now allow image quality improvements that make clinical applications feasible. Validation experiments were performed to characterize a new methodology and its imaging performance.

  16. Technology developments to initiate a next generation of cochlear implants.

    Science.gov (United States)

    Volckaerts, B; Corless, A R; Mercanzini, A; Silmon, A M; Bertsch, A; Van Himbeeck, C; Wasikiewicz, J; Vanden Bulcke, M; Vadgama, P; Renaud, P

    2007-01-01

    In the framework of the EU-supported research project Healthy Aims, we developed a range of novel electrode arrays and related technologies for use in hearing prosthesis. This paper summarizes our ongoing research activities on alternative electrode manufacturing routes, functional electrode interfaces and smart intra-cochlear and intra-modiolus electrode arrays.

  17. Temporal-Gap Detection by Cochlear Prosthesis Users.

    Science.gov (United States)

    Preece, John P.; Tyler, Richard S.

    1989-01-01

    Three experiments were undertaken involving three users of multi-electrode cochlear prostheses. The experiments established a scale of stimulus loudness; measured minimum-detectable gaps for sinusoidal stimuli as functions of stimulus level, frequency, and electrode place within the cochlea; and assessed independence of the electrodes using a…

  18. Multicenter study with a direct acoustic cochlear implant

    NARCIS (Netherlands)

    Lenarz, T.; Zwartenkot, J.W.; Stieger, C.; Schwab, B.; Mylanus, E.A.M.; Caversaccio, M.; Kompis, M.; Snik, A.F.M.; D'Hondt, C.; Mojallal, H.

    2013-01-01

    OBJECTIVE: To confirm the clinical efficacy and safety of a direct acoustic cochlear implant. STUDY DESIGN: Prospective multicenter study. SETTING: The study was performed at 3 university hospitals in Europe (Germany, The Netherlands, and Switzerland). PATIENTS: Fifteen patients with severe-to-profo

  19. Cortical Auditory Evoked Potentials in Unsuccessful Cochlear Implant Users

    Science.gov (United States)

    Munivrana, Boska; Mildner, Vesna

    2013-01-01

    In some cochlear implant users, success is not achieved in spite of optimal clinical factors (including age at implantation, duration of rehabilitation and post-implant hearing level), which may be attributed to disorders at higher levels of the auditory pathway. We used cortical auditory evoked potentials to investigate the ability to perceive…

  20. The effect of cochlear implant use in postlingually deaf adults

    NARCIS (Netherlands)

    Krabbe, P F; Hinderink, J B; van den Broek, P

    2000-01-01

    OBJECTIVE: To assess the effect of the use of cochlear implants (CI) on the health status of postlingually deaf adults. METHODS: Participants comprised 45 postlingually deaf adult multichannel CI users and 46 deaf candidates on the waiting list for a CI. The latter group acted as control subjects to

  1. Two new directions in speech processor design for cochlear implants.

    Science.gov (United States)

    Wilson, Blake S; Schatzer, Reinhold; Lopez-Poveda, Enrique A; Sun, Xiaoan; Lawson, Dewey T; Wolford, Robert D

    2005-08-01

    Two new approaches to the design of speech processors for cochlear implants are described. The first aims to represent "fine structure" or "fine frequency" information in a way that it can be perceived and used by patients, and the second aims to provide a closer mimicking than was previously possible of the signal processing that occurs in the normal cochlea.

  2. Cochlear Damage Affects Neurotransmitter Chemistry in the Central Auditory System

    Directory of Open Access Journals (Sweden)

    Donald Albert Godfrey

    2014-11-01

    Full Text Available Tinnitus, the perception of a monotonous sound not actually present in the environment, affects nearly 20% of the population of the United States. Although there has been great progress in tinnitus research over the past 25 years, the neurochemical basis of tinnitus is still poorly understood. We review current research about the effects of various types of cochlear damage on the neurotransmitter chemistry in the central auditory system and document evidence that different changes in this chemistry can underlie similar behaviorally measured tinnitus symptoms. Most available data have been obtained from rodents following cochlear damage produced by cochlear ablation, loud sound, or ototoxic drugs. Effects on neurotransmitter systems have been measured as changes in neurotransmitter level, synthesis, release, uptake, and receptors. In this review, magnitudes of changes are presented for neurotransmitter-related amino acids, acetylcholine, and serotonin. A variety of effects have been found in these studies that may be related to animal model, survival time, type of cochlear damage, or methodology. The overall impression from the evidence presented is that any imbalance of neurotransmitter-related chemistry could disrupt auditory processing in such a way as to produce tinnitus.

  3. Motor Development of Deaf Children with and without Cochlear Implants

    Science.gov (United States)

    Gheysen, Freja; Loots, Gerrit; Van Waelvelde, Hilde

    2008-01-01

    The purpose of this study was to investigate the impact of a cochlear implant (CI) on the motor development of deaf children. The study involved 36 mainstreamed deaf children (15 boys, 21 girls; 4- to 12-years old) without any developmental problems. Of these children, 20 had been implanted. Forty-three hearing children constituted a comparison…

  4. Temporal processing in postlingual adult users of cochlear implant

    Directory of Open Access Journals (Sweden)

    Maycon Duarte

    Full Text Available ABSTRACT INTRODUCTION: Postlingual adults demonstrate impressive performance in speech recognition in silence after cochlear implant (CI surgery. However, problems in central hearing abilities remain, which complicates understanding in certain situations, such as in competitive listening and in the perception of suprasegmental aspects of speech. OBJECTIVE: To assess the temporal processing abilities in postlingual adult users of CI. METHODS: Cross-sectional and descriptive study, with a non-probabilistic sample for convenience. The population was divided into two groups. The study group consisted of 12 postlingual adult users of cochlear implants and the control group consisted of 12 adults with normal hearing, matched for age and gender with the control group. The Frequency Pattern Test and the Gaps in Noise test were selected to assess temporal processing. Free-field testing was applied at 50 dB SL. RESULTS: Adult users of cochlear implant attained a mean temporal threshold of 16.33 ms and scored 47.7% in the pattern frequency test; the difference was statistically significant in comparison with the control group. CONCLUSION: It was verified that postlingual adult users of cochlear implants have significant alterations in temporal processing abilities in comparison to adults with normal hearing.

  5. Communication Intervention for Children with Cochlear Implants: Two Case Studies.

    Science.gov (United States)

    Ertmer, David J.; Leonard, Jeannette S.; Pachuilo, Michael L.

    2002-01-01

    This article describes the intervention programs attended and progress made by two children (ages 3 and 7) who exhibited considerable differences in benefit from their cochlear implants. Their intervention programs employed both analytical and synthetic auditory training and emphasized the development of speech production and language skills.…

  6. Acoustic and Semantic Enhancements for Children with Cochlear Implants

    Science.gov (United States)

    Smiljanic, Rajka; Sladen, Douglas

    2013-01-01

    Purpose: In this study, the authors examined how signal clarity interacts with the use of sentence context information in determining speech-in-noise recognition for children with cochlear implants and children with normal hearing. Method: One hundred and twenty sentences in which the final word varied in predictability (high vs. low semantic…

  7. Single Word and Sentence Intelligibility in Children with Cochlear Implants

    Science.gov (United States)

    Khwaileh, Fadwa A.; Flipsen, Peter, Jr.

    2010-01-01

    This study examined the intelligibility of speech produced by 17 children (aged 4-11 years) with cochlear implants. Stimulus items included sentences from the Beginners' Intelligibility Test (BIT) and words from the Children Speech Intelligibility Measure (CSIM). Naive listeners responded by writing sentences heard or with two types of responses…

  8. Cochlear Implants in the Inclusive Classroom: A Case Study

    Science.gov (United States)

    Jachova, Zora; Kovacevic, Jasmina

    2010-01-01

    This article presents a case study of a child aged 12 years with a cochlear implant who is attending a mainstream educational setting in Skopje, FYR Macedonia. The study, which uses both qualitative and quantitative data, took place over a period of 12 months. It illustrates the importance of professional development and training of teachers and a…

  9. Strategies for Working with Children with Cochlear Implants

    Science.gov (United States)

    Schraer-Joiner, Lyn; Prause-Weber, Manuela

    2009-01-01

    According to the National Institute on Deafness and Other Communication Disorders, 23,000 individuals in the United States, including 10,000 children, have a cochlear implant. This biomedical electronic device has been a breakthrough in the auditory rehabilitation of individuals diagnosed with severe or profound sensorineural hearing losses who…

  10. Spelling of Deaf Children Who Use Cochlear Implants

    Science.gov (United States)

    Hayes, Heather; Kessler, Brett; Treiman, Rebecca

    2011-01-01

    The spellings of 39 profoundly deaf users of cochlear implants, aged 6 to 12 years, were compared with those of 39 hearing peers. When controlled for age and reading ability, the error rates of the 2 groups were not significantly different. Both groups evinced phonological spelling strategies, performing better on words with more typical…

  11. Simultaneous Communication and Cochlear Implants in the Classroom?

    Science.gov (United States)

    Blom, Helen C.; Marschark, Marc

    2015-01-01

    This study was designed to evaluate the potential of simultaneous communication (sign and speech together) to support classroom learning by college students who use cochlear implants (CIs). Metacognitive awareness of learning also was evaluated. A within-subjects design involving 40 implant users indicated that the student participants learned…

  12. Speech Perception in Noise by Children with Cochlear Implants

    Science.gov (United States)

    Caldwell, Amanda; Nittrouer, Susan

    2013-01-01

    Purpose: Common wisdom suggests that listening in noise poses disproportionately greater difficulty for listeners with cochlear implants (CIs) than for peers with normal hearing (NH). The purpose of this study was to examine phonological, language, and cognitive skills that might help explain speech-in-noise abilities for children with CIs.…

  13. Patients with Pendred syndrome: is cochlear implantation beneficial?

    NARCIS (Netherlands)

    Nierop, J.W.I. van; Huinck, W.J.; Pennings, R.J.E.; Admiraal, R.J.C.; Mylanus, E.A.M.; Kunst, H.P.M.

    2016-01-01

    OBJECTIVE: To evaluate the benefit of cochlear implantation in patients with Pendred syndrome. DESIGN: Retrospective study. SETTING: Tertiary centre. PARTICIPANTS AND MAIN OUTCOME MEASURES: Speech perception was measured using a phonetically balanced word list at a sound pressure level of 65 dB. Pos

  14. Classroom performance of children with cochlear implants in mainstream education.

    NARCIS (Netherlands)

    Damen, G.W.J.A.; Oever-Goltstein, M.H. van den; Langereis, M.C.; Chute, P.M.; Mylanus, E.A.M.

    2006-01-01

    OBJECTIVES: We compared classroom performance of children with a cochlear implant (CI) with that of their normal-hearing peers in mainstream education. METHODS: Thirty-two CI children in mainstream education, congenitally or prelingually deaf, participated in this study, as did 37 hearing classmates

  15. The acquisition of personal pronouns in cochlear-implanted children

    NARCIS (Netherlands)

    Verbist, Annemie Josee Jozef

    2010-01-01

    Today, many deaf children can be given access to oral language thanks to a cochlear implant, a surgically implanted electronic device that provides a sense of sound thanks to electric stimulation of the auditory nerve. In this study, the acquisition of personal pronouns is considered to be a measure

  16. Concept Formation Skills in Long-Term Cochlear Implant Users

    Science.gov (United States)

    Castellanos, Irina; Kronenberger, William G.; Beer, Jessica; Colson, Bethany G.; Henning, Shirley C.; Ditmars, Allison; Pisoni, David B.

    2015-01-01

    This study investigated if a period of auditory sensory deprivation followed by degraded auditory input and related language delays affects visual concept formation skills in long-term prelingually deaf cochlear implant (CI) users. We also examined if concept formation skills are mediated or moderated by other neurocognitive domains (i.e.,…

  17. Connected speech intelligibility of children with cochlear implants and children with normal hearing.

    Science.gov (United States)

    Chin, Steven B; Tsai, Patrick L; Gao, Sujuan

    2003-11-01

    The objective of this study was to compare the connected speech intelligibility of children who use cochlear implants with that of children who have normal hearing. Previous research has shown that speech intelligibility improves from before cochlear implantation to after implantation and that the speech intelligibility of children who use cochlear implants compares favorably with that of children who use conventional hearing aids. However, no research has yet addressed the question of how the speech intelligibility of children who use cochlear implants compares to that of children with normal hearing. In the current study, archival data on connected speech intelligibility from 51 children with cochlear implants were compared with newly collected data from 47 children with normal hearing. Results showed that for children with cochlear implants, greater intelligibility was associated with both increased chronological age and increased duration of cochlear implant use. Consistent with previous studies, children with normal hearing achieved adult-like or near-adult-like intelligibility around the age of 4 years, but a similar peak in intelligibility was not observed for the children who used cochlear implants. On the whole, children with cochlear implants were significantly less intelligible than children with normal hearing, when controlling both for chronological age and for length of auditory experience. These results have implications for the socialization and education of children with cochlear implants, particularly with respect to on-time placement in mainstream educational environments with age peers.

  18. Hair bleaching and skin burning.

    Science.gov (United States)

    Forster, K; Lingitz, R; Prattes, G; Schneider, G; Sutter, S; Schintler, M; Trop, M

    2012-12-31

    Hairdressing-related burns are preventable and therefore each case is one too many. We report a unique case of a 16-yr-old girl who suffered full-thickness chemical and thermal burns to the nape of her neck and superficial burns to the occiput after her hair had been dyed blond and placed under a dryer to accelerate the highlighting procedure. The wound on the nape of the neck required surgical debridement and skin grafting. The grafted area resulted in subsequent scar formation.

  19. Recording of cochlear bioelectricities from facial nerve canal in rats%经大鼠面神经管引导耳蜗生物电反应

    Institute of Scientific and Technical Information of China (English)

    于进涛; 丁大连; 孙虹; Richard Salvi

    2014-01-01

    different structures and cells of the cochlea. Except for the EP, which is a resting potential mainly reflecting the function of stria vascularis, other cochlear potentials actually are the auditory evoked responses from cochlear sensory hair cells or auditory nerve fibers of spiral ganglion neurons respectively. Therefore, cochlear bioelectric activity recording is an ideal technique to study cochlear physiological functions. Many tradi-tional techniques for cochlear bioelectricity recording through middle ear cavity are not suited for long-term observation due to potential surgical injury or infection to the middle ear. With the expanding use of rats, rat model has been investigated to gain insights into the mechanisms underlying noise or drug-induced hearing loss. However, there lacks effective method for long-term recording of cochlear bioelectricity in rats. A stable long-term recording technique of cochlear potentials in rats is described in this report. A silver electrode was implanted into the horizontal segment of facial nerve canal via stylomastoid fora-men. Since the cochlear cavity is separated from facial nerve canal only by a thin osteal wall, the waveform of cochlear bioelec-tric activities can be easily recorded from within the facial nerve canal. In addition, this electrode insertion does not require opening the middle ear cavity and hence helps avoid surgical damage and infection to the middle ear. The CAP, CM and SP can be reliably recorded following electrode implantation. However, the amplitude of CAP and CM can vary among indivdual animals. This suggests that data analysis is probably more reliable with pre-vs post-treatment design than comparison across animals. In conclusion, electrode insert at the dissepiment of cochlea for recording of cochlear bioelectric activities may pro-vide a useful approach for hearing physiological studies in rats. Moreover, this paper also discusses the characteristics and in-trinsic relationships between different

  20. Can polar bear hairs absorb environmental energy?

    OpenAIRE

    He Ji-Huan; Wang Qing-Li; Sun Jie

    2011-01-01

    A polar bear (Ursus maritimus) has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.