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Sample records for chick cochlear hair

  1. Developmental expression of BK channels in chick cochlear hair cells

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    Tong Mingjie

    2009-12-01

    Full Text Available Abstract Background Cochlear hair cells are high-frequency sensory receptors. At the onset of hearing, hair cells acquire fast, calcium-activated potassium (BK currents, turning immature spiking cells into functional receptors. In non-mammalian vertebrates, the number and kinetics of BK channels are varied systematically along the frequency-axis of the cochlea giving rise to an intrinsic electrical tuning mechanism. The processes that control the appearance and heterogeneity of hair cell BK currents remain unclear. Results Quantitative PCR results showed a non-monotonic increase in BK α subunit expression throughout embryonic development of the chick auditory organ (i.e. basilar papilla. Expression peaked near embryonic day (E 19 with six times the transcript level of E11 sensory epithelia. The steady increase in gene expression from E11 to E19 could not explain the sudden acquisition of currents at E18-19, implicating post-transcriptional mechanisms. Protein expression also preceded function but progressed in a sequence from diffuse cytoplasmic staining at early ages to punctate membrane-bound clusters at E18. Electrophysiology data confirmed a continued refinement of BK trafficking from E18 to E20, indicating a translocation of BK clusters from supranuclear to subnuclear domains over this critical developmental age. Conclusions Gene products encoding BK α subunits are detected up to 8 days before the acquisition of anti-BK clusters and functional BK currents. Therefore, post-transcriptional mechanisms seem to play a key role in the delayed emergence of calcium-sensitive currents. We suggest that regulation of translation and trafficking of functional α subunits, near voltage-gated calcium channels, leads to functional BK currents at the onset of hearing.

  2. Intra- and extracellular calcium modulates stereocilia stiffness on chick cochlear hair cells.

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    Pae, S S; Saunders, J. C.

    1994-01-01

    Segments of the chick basilar papilla were isolated and maintained in culture medium. The sensory hair bundle of individual hair cells was observed with light microscopy and stimulated with a water microjet at 600 Hz. Hair bundle motion was slowed by illuminating the microscope with stroboscopic light, and water jet intensity was systematically varied in decibel (dB) steps until a visual detection level (VDL) threshold of hair bundle motion was achieved. The VDL threshold of many hair cells w...

  3. 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.

  4. Acoustic Trauma Increases Cochlear and Hair Cell Uptake of Gentamicin

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    Hongzhe Li; Qi Wang; Steyger, Peter S.

    2011-01-01

    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...

  5. 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.

  6. Noise alters hair-bundle mechanics at the cochlear apex

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    Strimbu, C. Elliott; Fridberger, Anders

    2015-12-01

    Exposure to loud sounds can lead to both permanent and short term changes in auditory sensitivity. Permanent hearing loss is often associated with gross changes in cochlear morphology including the loss of hair cells and auditory nerve fibers while the mechanisms of short term threshold shifts are much less well understood and may vary at different locations across the cochlea. Previous reports suggest that exposure to loud sounds leads to a decrease in the cochlear microphonic potential and in the stiffness of the organ of Corti. Because the cochlear microphonic reflects changes in the membrane potential of the hair cells, this suggests that hair-bundle motion should be reversibly altered following exposure to loud sounds. Using an in vitro preparation of the guinea pig temporal bone we investigate changes in the micro-mechanical response near the cochlear apex following a brief (up to 10 - 20 minutes) exposure to loud (˜ 120 dB) tones near the best frequency at this location. We use time-resolved confocal imaging to record the motion of outer hair cell bundles before and after acoustic overstimulation. We have also recorded larger-scale structural views of the organ of Corti before and after exposure to the loud sound. Conventional electrophysiological techniques are used measure the cochlear microphonic potential. As has been previously reported, following acoustic overexposure the cochlear microphonic declines in value and typically recovers on the order of 30 - 60 minutes. Hair-bundle trajectories are affected following the loud sound and typically recover on a somewhat faster time scale than the microphonic potential, although the results vary considerably across preparations. Preliminary results also suggest reversible changes in the hair cell's resting potential following the loud sound.

  7. Ephrin A2 protein expression in the regeneration and plasticity of cochlear hair cells in chicken following kanamycin ototoxicity

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    Jia Yu; Mingliang Xiang; Hao Wu; Chenling Shen

    2012-01-01

    The results from this study showed that the thresholds of brainstem auditory-evoked potentials peak following 10 successive days of intramuscular injection of Roman chickens with kanamycin, starting 3 days after birth. Fluorescence immunohistochemistry analysis revealed few ganglion cells positively labeled for Ephrin A2 in the cochlea of experimental chickens from 2 days before until 7 days after the last kanamycin injection. The number of Ephrin A2-positive ganglion cell bodies was increased at 15 days after the last injection and was similar to that in normal chickens at 30 days following the cessation of kanamycin treatment. These experimental findings indicate that Ephrin A2 protein expression in the acoustic ganglia is synchronized with the connection damage and regeneration of cochlear hair cells after kanamycin exposure. Ephrin A2 may play an important role in the regeneration and plasticity of cochlear hair cells in the chick cochlea following kanamycin ototoxicity.

  8. Fate of Mammalian Cochlear Hair Cells and Stereocilia after Loss of the Stereocilia

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    Jia, Shuping; Yang, Shiming; Guo, Weiwei; David Z Z He

    2009-01-01

    Cochlear hair cells transduce mechanical stimuli into electrical activity. The site of hair cell transduction is the hair bundle, an array of stereocilia with different height arranged in a staircase. Tip links connect the apex of each stereocilium to the side of its taller neighbor. The hair bundle and tip links of hair cells are susceptible to acoustic trauma and ototoxic drugs. It has been shown that hair cells in lower vertebrates and in the mammalian vestibular system may survive bundle ...

  9. 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.

  10. 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.

  11. Mammalin cochlear supporting cells transdifferentiation into outer hair cells

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    Liu Siwei; Zhang Shaoqiang; Zhu Hongliang; Li Baiya; Zheng Qingyin; Li Shengli

    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 of cells that could take up BrdU. Results After 15 days of gentamicin treatment, all of the animals were proved to be deafened with significant increases of ABR thresholds,compared with control group. The findings in immunocytochemical stained samples and scanning electron microscopy revealed that BrdU labeled nuclei were observed in the cochlea in all of the deafened animals most commonly in the regions of the first-row and second-row Deiter's cells (DCs) and occasionally in the regions of the third-ruw DCs.Conclusion We suggest that, under sufficient drug and enough time, the bat cochlear supporting cells can directly transdifferentiate into the outer hair cells after aminoglycoside exposure. This transdifferentation process is essential for repair of outer hair cells and recovery of normal function after gentamicin exposure.

  12. Adjudin protects rodent cochlear hair cells against gentamicin ototoxicity via the SIRT3-ROS pathway

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    Quan, Yizhou; Xia, Li; Shao, Jiaxiang; Yin, Shankai; Cheng, C. Yan; Xia, Weiliang; Gao, Wei-Qiang

    2015-01-01

    Hearing loss resulting from hair cell degeneration is a common disease that affects millions of people worldwide. Strategies to overcome the apparent irreversible hair cell loss in mammals become paramount for hearing protection. Here we reported that, by using a well-established gentamicin-induced hair cell loss model in vitro, adjudin, a multi-functional small molecule drug, protected cochlear hair cells from gentamicin damage. Immunohistochemistry, Western blotting and quantitative RT-PCR ...

  13. 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

  14. Glucose transporter 5 is undetectable in outer hair cells and does not contribute to cochlear amplification

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    Wu, Xudong; Wang, Xiang; Gao, Jiangang; Yu, Yiling; Jia, Shuping; Zheng, Jing; Dallos, Peter; David Z Z He; Cheatham, Mary Ann; Zuo, Jian

    2008-01-01

    Glucose transporter 5 (Glut5) is a high-affinity fructose transporter. It was proposed to be a motor protein or part of the motor complex required for cochlear amplification in outer hair cells (OHCs). Here we show that, in contrast to previous reports, Glut5 is undetectable, and possibly absent, in OHCs harvested from wildtype mice. Further, Glut5-deficient mice display normal OHC morphology and motor function (i.e., nonlinear capacitance and electromotility) and normal cochlear sensitivity....

  15. 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.

  16. Hair Barrette Induced Cochlear Implant Receiver Stimulator Site Infection with Extrusion

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    Trung N. Le

    2015-01-01

    Full Text Available Background. Cochlear implant infections and extrusion are uncommon but potentially devastating complications. Recent literature suggests conservative management can be employed. Local measures inclusive of aggressive surgical debridement with vascularized flaps and parenteral antibiotics represent a viable option and often permit device salvage. However, explantation should be considered if there is evidence of systemic, intracranial, or intractable infection. Method. A Case report and literature review. Case Report. This case illustrates a complicated local wound infection associated with cochlear implantation due to transcutaneous adherence of a ferrous hair barrette to a cochlear implant magnet. Reconstruction of computed tomography (CT data with 3D volume rendering significantly improved the value of the images and facilitated patient counseling as well as operative planning. Conclusion. Cochlear implant infections can be associated with foreign bodies. CT images are beneficial in the evaluation of cochlear implant complications. 3D CT images provide a comprehensive view of the site of interest, displaying the relationship of the hardware to the skull and soft tissues, while minimizing associated artifacts. Cochlear implant patients should consider use of nonmetallic hair devices.

  17. 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.

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

    International Nuclear Information System (INIS)

    Highlights: ► Shh activation in neonatal cochleae enhances sensory cell proliferation. ► Proliferating supporting cells can transdifferentiate into hair cells. ► Shh promotes proliferation by transiently modulating pRb activity. ► 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.

  19. Different uptake of gentamicin through TRPV1 and TRPV4 channels determines cochlear hair cell vulnerability

    OpenAIRE

    Lee, Jeong-Han; Park, Channy; Kim, Se-Jin; Kim, Hyung-Jin; Oh, Gi-Su; Shen, Aihua; So, Hong-Seob; Park, Raekil

    2013-01-01

    Hair cells at the base of the cochlea appear to be more susceptible to damage by the aminoglycoside gentamicin than those at the apex. However, the mechanism of base-to-apex gradient ototoxicity by gentamicin remains to be elucidated. We report here that gentamicin caused rodent cochlear hair cell damages in a time- and dose-dependent manner. Hair cells at the basal turn were more vulnerable to gentamicin than those at the apical turn. Gentamicin-conjugated Texas Red (GTTR) uptake was predomi...

  20. Mechanoelectrical Transducer Has Discrete Conductances in the Chick Vestibular Hair Cell

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    Ohmori, Harunori

    1984-03-01

    Properties of mechanoelectrical transduction were studied at the single-cell level by applying a whole-cell recording variation of the patch-clamp technique to dissociated vestibular hair cells of chicks. The hair bundle was directly stimulated by a glass rod, and transduction currents were recorded from the cell body. After a triangular movement of the stimulating probe, the transduction current was generated stepwise between discrete levels of amplitude. The minimum step amplitude was -1.8 pA at -27 mV in Na-containing normal saline.

  1. Effectiveness of Hair Bundle Motility as the Cochlear Amplifier

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    Sul, Bora; Iwasa, Kuni H.

    2009-01-01

    The effectiveness of hair bundle motility in mammalian and avian ears is studied by examining energy balance for a small sinusoidal displacement of the hair bundle. The condition that the energy generated by a hair bundle must be greater than energy loss due to the shear in the subtectorial gap per hair bundle leads to a limiting frequency that can be supported by hair-bundle motility. Limiting frequencies are obtained for two motile mechanisms for fast adaptation, the channel re-closure mode...

  2. The mechanism of pneumolysin-induced cochlear hair cell death in the rat.

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    Beurg, Maryline; Hafidi, Aziz; Skinner, Liam; Cowan, Graeme; Hondarrague, Yannick; Mitchell, Tim J; Dulon, Didier

    2005-10-01

    Streptoccocus pneumoniae infection can result in local and systemic diseases such as otitis media, pneumonia and meningitis. Sensorineural hearing loss associated with this infection is mediated by the release of an exotoxin, pneumolysin. The goal of the present study was to characterize the mechanisms of pneumolysin toxicity in cochlear hair cells in vitro. Pneumolysin induced severe damage in cochlear hair cells, ranging from stereocilia disorganization to total cell loss. Surprisingly, pneumolysin-induced cell death preferentially targeted inner hair cells. Pneumolysin triggered in vitro cell death by an influx of calcium. Extracellular calcium appeared to enter the cell through a pore formed by the toxin. Buffering intracellular calcium with BAPTA improved hair cell survival. The mitochondrial apoptotic pathway involved in pneumolysin-induced cell death was demonstrated by the use of bongkrekic acid. Binding of pneumolysin to the hair cell plasma membrane was required to induce cell death. Increasing external calcium reduced cell toxicity by preventing the binding of pneumolysin to hair cell membranes. These results showed the significant role of calcium both in triggering pneumolysin-induced hair cell apoptosis and in preventing the toxin from binding to its cellular target. PMID:16051626

  3. Distinct roles of Eps8 in the maturation of cochlear and vestibular hair cells.

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    Tavazzani, Elisa; Spaiardi, Paolo; Zampini, Valeria; Contini, Donatella; Manca, Marco; Russo, Giancarlo; Prigioni, Ivo; Marcotti, Walter; Masetto, Sergio

    2016-07-22

    Several genetic mutations affecting the development and function of mammalian hair cells have been shown to cause deafness but not vestibular defects, most likely because vestibular deficits are sometimes centrally compensated. The study of hair cell physiology is thus a powerful direct approach to ascertain the functional status of the vestibular end organs. Deletion of Epidermal growth factor receptor pathway substrate 8 (Eps8), a gene involved in actin remodeling, has been shown to cause deafness in mice. While both inner and outer hair cells from Eps8 knockout (KO) mice showed abnormally short stereocilia, inner hair cells (IHCs) also failed to acquire mature-type ion channels. Despite the fact that Eps8 is also expressed in vestibular hair cells, Eps8 KO mice show no vestibular deficits. In the present study we have investigated the properties of vestibular Type I and Type II hair cells in Eps8-KO mice and compared them to those of cochlear IHCs. In the absence of Eps8, vestibular hair cells show normally long kinocilia, significantly shorter stereocilia and a normal pattern of basolateral voltage-dependent ion channels. We have also found that while vestibular hair cells from Eps8 KO mice show normal voltage responses to injected sinusoidal currents, which were used to mimic the mechanoelectrical transducer current, IHCs lose their ability to synchronize their responses to the stimulus. We conclude that the absence of Eps8 produces a weaker phenotype in vestibular hair cells compared to cochlear IHCs, since it affects the hair bundle morphology but not the basolateral membrane currents. This difference is likely to explain the absence of obvious vestibular dysfunction in Eps8 KO mice. PMID:27132230

  4. Lateral mechanical coupling of stereocilia in cochlear hair bundles.

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    Langer, M G; Fink, S; Koitschev, A; Rexhausen, U; Hörber, J K; Ruppersberg, J P

    2001-06-01

    For understanding the gating process of transduction channels in the inner ear it is essential to characterize and examine the functional properties of the ultrastructure of stereociliary bundles. There is strong evidence that transduction channels in hair cells are gated by directly pulling at the so-called tip links. In addition to these tip links a second class of filamentous structures was identified in the scanning and transmission electron microscope: the side-to-side links. These links laterally connect stereocilia of the same row of a hair bundle. This study concentrates on mechanical coupling of stereocilia of the tallest row connected by side-to-side links. Atomic Force microscopy (AFM) was used to investigate hair bundles of outer hair cells (OHCs) from postnatal rats (day 4). Although hair bundles of postnatal rats are still immature at day 4 and interconnecting cross-links do not show preferential direction yet, hair bundles of investigated OHCs already showed the characteristic V-shape of mature hair cells. In a first experiment, the stiffness of stereocilia was investigated scanning individual stereocilia with an AFM tip. The spring constant for the excitatory direction was 2.5 +/- 0.6 x 10(-3) N/m whereas a higher spring constant (3.1 +/- 1.5 x 10(-3) N/m) was observed in the inhibitory direction. In a second set of experiments, the force transmission between stereocilia of the tallest row was measured using AFM in combination with a thin glass fiber. This fiber locally displaced a stereocilium while the force laterally transmitted to the neighboring untouched taller stereocilia was measured by AFM. The results show a weak force interaction between tallest stereocilia of postnatal rats. The force exerted to an individual stereocilium declines to 36% at the nearest adjacent stereocilium of the same row not touched with the fiber. It is suggested that the amount of force transmitted from a taller stereocilium to an adjacent one of the same row depends

  5. Activity-dependent regulation of calcium and ribosomes in the chick cochlear nucleus.

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    Call, C L; Hyson, R L

    2016-03-01

    Cochlea removal results in the death of 20-30% of neurons in the chick cochlear nucleus, nucleus magnocellularis (NM). Two potentially cytotoxic events, a dramatic rise in intracellular calcium concentration ([Ca(2+)]i) and a decline in the integrity of ribosomes are observed within 1h of deafferentation. Glutamatergic input from the auditory nerve has been shown to preserve NM neuron health by activating metabotropic glutamate receptors (mGluRs), maintaining both normal [Ca(2+)]i and ribosomal integrity. One interpretation of these results is that a common mGluR-activated signaling cascade is required for the maintenance of both [Ca(2+)]i and ribosomal integrity. This could happen if both responses are influenced directly by a common messenger, or if the loss of mGluR activation causes changes in one component that secondarily causes changes in the other. The present studies tested this common-mediator hypothesis in slice preparations by examining activity-dependent regulation of [Ca(2+)]i and ribosomes in the same tissue after selectively blocking group I mGluRs (1-Aminoindan-1,5-dicarboxylic acid (AIDA)) or group II mGluRs (LY 341495) during unilateral auditory nerve stimulation. Changes in [Ca(2+)]i of NM neurons were measured using fura-2 ratiometric calcium imaging and the tissue was subsequently processed for Y10B immunoreactivity (Y10B-ir), an antibody that recognizes a ribosomal epitope. The group I mGluR antagonist blocked the activity-dependent regulation of both [Ca(2+)]i and Y10B-ir, but the group II antagonist blocked only the activity-dependent regulation of Y10B-ir. That is, even when group II receptors were blocked, stimulation continued to maintain low [Ca(2+)]i, but it did not maintain Y10B-ir. These results suggest a dissociation in how calcium and ribosomes are regulated in NM neurons and that ribosomes can be regulated through a mechanism that is independent of calcium regulation. PMID:26739326

  6. Lateral mechanical coupling of stereocilia in cochlear hair bundles.

    OpenAIRE

    Langer, M G; Fink, S.; Koitschev, A; Rexhausen, U; Hörber, J K; Ruppersberg, J P

    2001-01-01

    For understanding the gating process of transduction channels in the inner ear it is essential to characterize and examine the functional properties of the ultrastructure of stereociliary bundles. There is strong evidence that transduction channels in hair cells are gated by directly pulling at the so-called tip links. In addition to these tip links a second class of filamentous structures was identified in the scanning and transmission electron microscope: the side-to-side links. These links...

  7. All Three Rows of Outer Hair Cells Are Required for Cochlear Amplification

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    Michio Murakoshi

    2015-01-01

    Full Text Available In the mammalian auditory system, the three rows of outer hair cells (OHCs located in the cochlea are thought to increase the displacement amplitude of the organ of Corti. This cochlear amplification is thought to contribute to the high sensitivity, wide dynamic range, and sharp frequency selectivity of the hearing system. Recent studies have shown that traumatic stimuli, such as noise exposure and ototoxic acid, cause functional loss of OHCs in one, two, or all three rows. However, the degree of decrease in cochlear amplification caused by such functional losses remains unclear. In the present study, a finite element model of a cross section of the gerbil cochlea was constructed. Then, to determine effects of the functional losses of OHCs on the cochlear amplification, changes in the displacement amplitude of the basilar membrane (BM due to the functional losses of OHCs were calculated. Results showed that the displacement amplitude of the BM decreases significantly when a single row of OHCs lost its function, suggesting that all three rows of OHCs are required for cochlear amplification.

  8. 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

  9. 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...

  10. Innervation of Cochlear Hair Cells by Human Induced Pluripotent Stem Cell-Derived Neurons In Vitro

    Science.gov (United States)

    Gunewardene, Niliksha; Crombie, Duncan; Dottori, Mirella; Nayagam, Bryony A.

    2016-01-01

    Induced pluripotent stem cells (iPSCs) may serve as an autologous source of replacement neurons in the injured cochlea, if they can be successfully differentiated and reconnected with residual elements in the damaged auditory system. Here, we explored the potential of hiPSC-derived neurons to innervate early postnatal hair cells, using established in vitro assays. We compared two hiPSC lines against a well-characterized hESC line. After ten days' coculture in vitro, hiPSC-derived neural processes contacted inner and outer hair cells in whole cochlear explant cultures. Neural processes from hiPSC-derived neurons also made contact with hair cells in denervated sensory epithelia explants and expressed synapsin at these points of contact. Interestingly, hiPSC-derived neurons cocultured with hair cells at an early stage of differentiation formed synapses with a higher number of hair cells, compared to hiPSC-derived neurons cocultured at a later stage of differentiation. Notable differences in the innervation potentials of the hiPSC-derived neurons were also observed and variations existed between the hiPSC lines in their innervation efficiencies. Collectively, these data illustrate the promise of hiPSCs for auditory neuron replacement and highlight the need to develop methods to mitigate variabilities observed amongst hiPSC lines, in order to achieve reliable clinical improvements for patients. PMID:26966437

  11. Mechanical stimulation of individual stereocilia of living cochlear hair cells by atomic force microscopy.

    Science.gov (United States)

    Langer, M G; Koitschev, A; Haase, H; Rexhausen, U; Hörber, J K; Ruppersberg, J P

    2000-02-01

    This paper describes the investigation of elastical properties and imaging of living cochlear hair bundles of inner (IHC) and outer hair cells (OHC) on the level of individual stereocilia. A custom-made AFM-setup was used, allowing to scan the mechano-sensitive structures of the inner ear under direct control of an upright differential interference contrast (DIC) microscope with a water-immersion objective. Scanning electron microscopy (SEM) images of the identical hair bundles obtained after AFM investigation demonstrated that forces up to 1.5 nanonewton (nN) did not cause obvious damage of the surface morphology of the stereocilia. These are the first images of hair bundles of living sensory cells of the organ of Corti by AFM. They display the tips of individual stereocilia and the typical V-shape of ciliary bundles. Since line scans clearly show that slope and force interaction depend on the elastical properties of stereocilia, quantitative stiffness measurements and stimulation of single transduction channels are suggested. PMID:10741679

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

    Science.gov (United States)

    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.

  13. In vivo Notch Reactivation in Differentiating Cochlear Hair Cells Induces Sox2 and Prox1 Expression but Does Not Disrupt Hair Cell Maturation

    OpenAIRE

    Liu, Zhiyong; Owen, Thomas; Fang, Jie; Srinivasan, R. Sathish; Zuo, Jian

    2012-01-01

    Notch signaling is active in mouse cochlear prosensory progenitors but declines in differentiating sensory hair cells (HCs). Overactivation of the Notch1 intracellular domain (NICD) in progenitors blocks HC fate commitment and/or differentiation. However, it is not known whether reactivation of NICD in differentiating HCs also interrupts their developmental program and reactivates its downstream targets. By analyzing Atoh1CreER+; Rosa26-NICDloxp/+ or Atoh1CreER+; Rosa26-NICDloxp/+; RBP-Jloxp/...

  14. 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.

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

    Science.gov (United States)

    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.

  16. Deletion of Tricellulin Causes Progressive Hearing Loss Associated with Degeneration of Cochlear Hair Cells.

    Science.gov (United States)

    Kamitani, Toru; Sakaguchi, Hirofumi; Tamura, Atsushi; Miyashita, Takenori; Yamazaki, Yuji; Tokumasu, Reitaro; Inamoto, Ryuhei; Matsubara, Ai; Mori, Nozomu; Hisa, Yasuo; Tsukita, Sachiko

    2015-01-01

    Tricellulin (also known as MARVELD2) is considered as a central component of tricellular tight junctions and is distributed among various epithelial tissues. Although mutations in the gene encoding tricellulin are known to cause deafness in humans (DFNB49) and mice, the influence of its systemic deletion in vivo remains unknown. When we generated tricellulin-knockout mice (Tric(-/-)), we found an early-onset rapidly progressive hearing loss associated with the degeneration of hair cells (HCs); however, their body size and overall appearance were normal. Tric(-/-) mice did not show any morphological change pertaining to other organs such as the gastrointestinal tract, liver, kidney, thyroid gland and heart. The endocochlear potential (EP) was normal in Tric(-/-) mice, suggesting that the tight junction barrier is maintained in the stria vascularis, where EP is generated. The degeneration of HCs, which occurred after the maturation of EP, was prevented in the culture medium with an ion concentration similar to that of the perilymph. These data demonstrate the specific requirement of tricellulin for maintaining ion homeostasis around cochlear HCs to ensure their survival. The Tric(-/-) mouse provides a new model for understanding the distinct roles of tricellulin in different epithelial systems as well as in the pathogenesis of DFNB49. PMID:26677943

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

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    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.

  20. 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.

  1. 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

  2. Selective hair cell ablation and noise exposure lead to different patterns of changes in the cochlea and the cochlear nucleus.

    Science.gov (United States)

    Kurioka, Takaomi; Lee, Min Young; Heeringa, Amarins N; Beyer, Lisa A; Swiderski, Donald L; Kanicki, Ariane C; Kabara, Lisa L; Dolan, David F; Shore, Susan E; Raphael, Yehoash

    2016-09-22

    In experimental animal models of auditory hair cell (HC) loss, insults such as noise or ototoxic drugs often lead to secondary changes or degeneration in non-sensory cells and neural components, including reduced density of spiral ganglion neurons, demyelination of auditory nerve fibers and altered cell numbers and innervation patterns in the cochlear nucleus (CN). However, it is not clear whether loss of HCs alone leads to secondary degeneration in these neural components of the auditory pathway. To elucidate this issue, we investigated changes of central components after cochlear insults specific to HCs using diphtheria toxin receptor (DTR) mice expressing DTR only in HCs and exhibiting complete HC loss when injected with diphtheria toxin (DT). We showed that DT-induced HC ablation has no significant impacts on the survival of auditory neurons, central synaptic terminals, and myelin, despite complete HC loss and profound deafness. In contrast, noise exposure induced significant changes in synapses, myelin and CN organization even without loss of inner HCs. We observed a decrease of neuronal size in the auditory pathway, including peripheral axons, spiral ganglion neurons, and CN neurons, likely due to loss of input from the cochlea. Taken together, selective HC ablation and noise exposure showed different patterns of pathology in the auditory pathway and the presence of HCs is not essential for the maintenance of central synaptic connectivity and myelination. PMID:27403879

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. How do the medial olivocochlear efferents influence the biomechanics of the outer hair cells and thereby the cochlear amplifier? Simulation results

    Science.gov (United States)

    Saremi, Amin; Stenfelt, Stefan; Verhulst, Sarah

    2015-12-01

    The bottom-up signal pathway, which starts from the outer ear and leads to the brain cortices, gives the classic image of the human sound perception. However, there have been growing evidences in the last six decades for existence of a functional descending network whereby the central auditory system can modulate the early auditory processing, in a top-down manner. The medial olivocochlear efferent fibers project from the superior olivary complex at the brainstem into the inner ear. They are linked to the basal poles of the hair cells by forming synaptic cisterns. This descending network can activate nicotinic cholinergic receptors (nAChR) that increase the membrane conductance of the outer hair cells and thereby modify the magnitude of the active force generated inside the cochlea. The aim of the presented work is to quantitatively investigate how the changes in the biomechanics of the outer hair cells, caused by the efferent activation, manipulate the cochlear responses. This is done by means of a frequency-domain biophysical model of the cochlea [12] where the parameters of the model convey physiological interpretations of the human cochlear structures. The simulations manifest that a doubling of the outer hair cell conductance, due to efferent activation, leads to a frequency-dependent gain reduction along the cochlear duct with its highest effect at frequencies between 1 kHz and 3.5 kHz and a maximum of approximately 10 dB gain reduction at 2 kHz. This amount of the gain inhibition and its frequency dependence reasonably agrees with the experimental data recorded from guinea pig, cat and human cochleae where the medial olivococlear efferents had been elicited by broad-band stimuli. The simulations also indicate that the efferent-induced increase of the outer hair cell conductance increases the best frequency of the cochlear responses, in the basal region. The presented simulations quantitatively confirm that activation of the medial olivocochlear efferents can

  6. Noise exposure modulates cochlear inner hair cell ribbon volumes, correlating with changes in auditory measures in the FVB/nJ mouse

    Science.gov (United States)

    Paquette, Stephen T.; Gilels, Felicia; White, Patricia M.

    2016-01-01

    Cochlear neuropathy resulting from unsafe noise exposure is a life altering condition that affects many people. This hearing dysfunction follows a conserved mechanism where inner hair cell synapses are lost, termed cochlear synaptopathy. Here we investigate cochlear synaptopathy in the FVB/nJ mouse strain as a prelude for the investigation of candidate genetic mutations for noise damage susceptibility. We used measurements of auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) to assess hearing recovery in FVB/nJ mice exposed to two different noise levels. We also utilized confocal fluorescence microscopy in mapped whole mount cochlear tissue, in conjunction with deconvolution and three-dimensional modeling, to analyze numbers, volumes and positions of paired synaptic components. We find evidence for significant synapse reorganization in response to both synaptopathic and sub-synaptopathic noise exposures in FVB/nJ. Specifically, we find that the modulation in volume of very small synaptic ribbons correlates with the presence of reduced ABR peak one amplitudes in both levels of noise exposures. These experiments define the use of FVB/nJ mice for further genetic investigations into the mechanisms of noise damage. They further suggest that in the cochlea, neuronal-inner hair cell connections may dynamically reshape as part of the noise response. PMID:27162161

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

    OpenAIRE

    Quanwen Liu; Yi Shen; Jiarong Chen; Jie Ding; Zihua Tang; Cui Zhang; Jianling Chen; Liang Li; Ping Chen; Jinfu Wang

    2016-01-01

    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 bund...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Liu, Ke; Li, ShuNa; Jiang, XueJun

    2009-09-01

    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. PMID:19802738

  10. 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)

    LIU Ke; LI ShuNa; JIANG XueJun

    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.

  11. Cochlear Outer-Hair-Cell Power Generation and Viscous Fluid Loss

    OpenAIRE

    Yanli Wang; Steele, Charles R.; Sunil Puria

    2016-01-01

    Since the discovery of otoacoustic emissions and outer hair cell (OHC) motility, the fundamental question of whether the cochlea produces mechanical power remains controversial. In the present work, direct calculations are performed on power loss due to fluid viscosity and power generated by the OHCs. A three-dimensional box model of the mouse cochlea is used with a feed-forward/feed-backward approximation representing the organ of Corti cytoarchitecture. The model is fit to in vivo basilar m...

  12. 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

  13. 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.

  14. Cockayne Syndrome Group B (Csb) and Group A (Csa) Deficiencies Predispose to Hearing Loss and Cochlear Hair Cell Degeneration in Mice

    Science.gov (United States)

    Nagtegaal, A. Paul; Rainey, Robert N.; van der Pluijm, Ingrid; Brandt, Renata M.C.; van der Horst, Gijsbertus T.J.

    2015-01-01

    Sensory hair cells in the cochlea, like most neuronal populations that are postmitotic, terminally differentiated, and non-regenerating, depend on robust mechanisms of self-renewal for lifelong survival. We report that hair cell homeostasis requires a specific sub-branch of the DNA damage nucleotide excision repair pathway, termed transcription-coupled repair (TCR). Cockayne syndrome (CS), caused by defects in TCR, is a rare DNA repair disorder with a broad clinical spectrum that includes sensorineural hearing loss. We tested hearing and analyzed the cellular integrity of the organ of Corti in two mouse models of this disease with mutations in the Csb gene (CSBm/m mice) and Csa gene (Csa−/− mice), respectively. Csbm/m and Csa−/− mice manifested progressive hearing loss, as measured by an increase in auditory brainstem response thresholds. In contrast to wild-type mice, mutant mice showed reduced or absent otoacoustic emissions, suggesting cochlear outer hair cell impairment. Hearing loss in Csbm/m and Csa−/− mice correlated with progressive hair cell loss in the base of the organ of Corti, starting between 6 and 13 weeks of age, which increased by 16 weeks of age in a basal-to-apical gradient, with outer hair cells more severely affected than inner hair cells. Our data indicate that the hearing loss observed in CS patients is reproduced in mouse models of this disease. We hypothesize that accumulating DNA damage, secondary to the loss of TCR, contributes to susceptibility to hearing loss. PMID:25762674

  15. 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

  16. 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.

  17. Cochlear Gene Therapy

    OpenAIRE

    Lustig, Lawrence R.; Akil, Omar

    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.

  18. 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.

  19. 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.

  20. Transmitter release from cochlear hair cells is phase locked to cyclic stimuli of different intensities and frequencies.

    Science.gov (United States)

    Goutman, Juan D

    2012-11-21

    The auditory system processes time and intensity through separate brainstem pathways to derive spatial location as well as other salient features of sound. The independent coding of time and intensity begins in the cochlea, where afferent neurons can fire action potentials at constant phase throughout a wide range of stimulus intensities. We have investigated time and intensity coding by simultaneous presynaptic and postsynaptic recording at the hair cell-afferent synapse from rats. Trains of depolarizing steps to the hair cell were used to elicit postsynaptic currents that occurred at constant phase for a range of membrane potentials over which release probability varied significantly. To probe the underlying mechanisms, release was examined using single steps to various command voltages. As expected for vesicular release, first synaptic events occurred earlier as presynaptic calcium influx grew larger. However, synaptic depression produced smaller responses with longer first latencies. Thus, during repetitive hair cell stimulation, as the hair cell is more strongly depolarized, increased calcium channel gating hurries transmitter release, but the resulting vesicular depletion produces a compensatory slowing. Quantitative simulation of ribbon function shows that these two factors varied reciprocally with hair cell depolarization (stimulus intensity) to produce constant synaptic phase. Finally, we propose that the observed rapid vesicle replenishment would help maintain the vesicle pool, which in turn would equilibrate with the stimulus intensity (and therefore the number of open Ca(2+) channels), so that for trains of different levels the average phase will be conserved. PMID:23175853

  1. Cochlear microphonic broad tuning curves

    Science.gov (United States)

    Ayat, Mohammad; Teal, Paul D.; Searchfield, Grant D.; Razali, Najwani

    2015-12-01

    It is known that the cochlear microphonic voltage exhibits much broader tuning than does the basilar membrane motion. The most commonly used explanation for this is that when an electrode is inserted at a particular point inside the scala media, the microphonic potentials of neighbouring hair cells have different phases, leading to cancelation at the electrodes location. In situ recording of functioning outer hair cells (OHCs) for investigating this hypothesis is exceptionally difficult. Therefore, to investigate the discrepancy between the tuning curves of the basilar membrane and those of the cochlear microphonic, and the effect of phase cancellation of adjacent hair cells on the broadness of the cochlear microphonic tuning curves, we use an electromechanical model of the cochlea to devise an experiment. We explore the effect of adjacent hair cells (i.e., longitudinal phase cancellation) on the broadness of the cochlear microphonic tuning curves in different locations. The results of the experiment indicate that active longitudinal coupling (i.e., coupling with active adjacent outer hair cells) only slightly changes the broadness of the CM tuning curves. The results also demonstrate that there is a π phase difference between the potentials produced by the hair bundle and the soma near the place associated with the characteristic frequency based on place-frequency maps (i.e., the best place). We suggest that the transversal phase cancellation (caused by the phase difference between the hair bundle and the soma) plays a far more important role than longitudinal phase cancellation in the broadness of the cochlear microphonic tuning curves. Moreover, by increasing the modelled longitudinal resistance resulting the cochlear microphonic curves exhibiting sharper tuning. The results of the simulations suggest that the passive network of the organ of Corti determines the phase difference between the hair bundle and soma, and hence determines the sharpness of the

  2. Recovery of mechano-electrical transduction in rat cochlear hair bundles after postnatal destruction of the stereociliar cross-links

    OpenAIRE

    Ebert, J.; Fink, S.; Koitschev, A; P. Walther; Langer, M G; Lehmann-Horn, F.

    2010-01-01

    Mechano-electrical transduction (MET) in the stereocilia of outer hair cells (OHCs) was studied in newborn Wistar rats using scanning electron microscopy to investigate the stereociliar cross-links, Nomarski laser differential interferometry to investigate stereociliar stiffness and by testing the functionality of the MET channels by recording the entry of fluorescent dye, FM1-43, into stereocilia. Preparations were taken from rats on their day of birth (P0) or 1–4 days later (P1–P4). Hair bu...

  3. 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

  4. 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.

  5. Recovery of mechano-electrical transduction in rat cochlear hair bundles after postnatal destruction of the stereociliar cross-links.

    Science.gov (United States)

    Ebert, J; Fink, S; Koitschev, A; Walther, P; Langer, M G; Lehmann-Horn, F

    2010-08-01

    Mechano-electrical transduction (MET) in the stereocilia of outer hair cells (OHCs) was studied in newborn Wistar rats using scanning electron microscopy to investigate the stereociliar cross-links, Nomarski laser differential interferometry to investigate stereociliar stiffness and by testing the functionality of the MET channels by recording the entry of fluorescent dye, FM1-43, into stereocilia. Preparations were taken from rats on their day of birth (P0) or 1-4 days later (P1-P4). Hair bundles developed from the base to the apex and from the inner to outer OHC rows. MET channel responses were detected in apical coil OHCs on P1. To study the possible recovery of MET after disrupting the cross-links, the same investigations were performed after the application of Ca(2+) chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) and allowing the treated samples to recover in culture medium for 0-20 h. We found that the structure and function were abolished by BAPTA. In P0-P1 samples, structural recovery was complete and the open probability of MET channels reached control values. In P3-P4 samples, complete recovery only occurred in OHCs of the outermost row. Although our results demonstrate an enormous recovery potential of OHCs in the postnatal period, the structural component restricts the potential for therapy in patients. PMID:20356889

  6. 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.

  7. D-galactose-induced cochlear hair cell apoptosis in newborn rats%D-半乳糖致新生大鼠耳蜗毛细胞凋亡

    Institute of Scientific and Technical Information of China (English)

    于飞; 郝帅; 杨军

    2013-01-01

    目的:观察发育期D-半乳糖暴露诱导新生大鼠耳蜗毛细胞凋亡.方法:12只孕鼠被随机分为两组(对照组和半乳糖组).自妊娠第6天起,对照组喂饲普通饲料,半乳糖组喂饲普通饲料配30%D-半乳糖的混合饲料.出生后21d检测仔鼠血清半乳糖水平,应用原位末端转移酶标记技术(terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labelling,TUNEL)染色和免疫组化检测仔鼠毛细胞凋亡情况.结果:孕期和哺乳期D-半乳糖暴露引起仔鼠耳蜗细胞凋亡发生及caspase-3免疫阳性表达增强.结论:孕期和哺乳期D-半乳糖摄入过量可致子代大鼠耳蜗毛细胞凋亡.%Objective: To observe the effect of D-galactose-induced apoptosis on the development of cochlear in newborn rats. Methods; The pregnant rats (n = 12) were randomly assigned to one of two groups from gestational day 6; control group was fed standard rodent diet , galactose group was fed standard rodent diet , supplemented with 30% galactose. On postnatal day 21, blood levels of galactose were measured in pups . The temporal bones were immunohistochemically stained for caspase -3 , using the terminal deoxynucleotidyl transferase -mediated dUTP-biotin nick end-labelling (TUNEL) method. Results; Hair cells apoptosis and caspase-3 expression were significantly observed in newborn rats with pregnant D-galactose exposure. Conclusion; D-galactose exposure may induce ototoxicity through hair cell apoptosis.

  8. 卡那霉素和速尿联合用药后的毛细胞死亡*%The Death Duration and Model of Cochlear Hair Cells in Guinea Pigs after the Combined Administration of Kanamycin and Furosemide

    Institute of Scientific and Technical Information of China (English)

    张贤芬; 孙东绣; 孙爱玲; 杨仕明; 胡吟燕; 郭维; 韩东一

    2013-01-01

      目的观察卡那霉素和速尿联合用药后豚鼠耳蜗毛细胞的死亡时程和方式。方法选用健康成年白色红目豚鼠,雌雄不限,随机分成健康对照组和药物致聋后6 h、9 h组(实验组),每组5只。实验组在选取的时间点完成听性脑干反应(ABR)检测后行耳蜗基底膜铺片、PI荧光染色,共聚焦显微镜下观察毛细胞。对照组不做处理。结果实验组半数豚鼠致聋(ABR阈值>95 dB SPL),致聋豚鼠耳蜗可见外毛细胞核固缩和核肿胀,与给药6 h组相比,给药9 h组外毛细胞核肿胀数目增多。检测给药6 h组和9 h组豚鼠末端脱氧核苷酸转移酶介导的dUTP缺口末端标记物(terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling,TUNEL),没有观察到阳性着色细胞。正常对照组所有豚鼠ABR正常,其耳蜗各回毛细胞没有出现毛细胞核固缩或者核肿胀。结论卡那霉素和速尿联合用药后数小时即可导致豚鼠耳蜗毛细胞死亡,毛细胞损害为两种类型,即坏死和凋亡。%Objective To observe the death duration and model of cochlear hair cells in guinea pigs after the administration of kanamycin and Furosemide. Methods Healthy adult white guinea pigs with red eyes were randomly selected without consideration of gender. These guinea pigs were randomly divided into 3 groups with 5 guinea pigs in each group, i.e. control group, 6 h after drug administration group and 9 h after drug administration group. After receiving ABR test at specific time, the cochlear basilar membrane of the experimental group was processed by stretched preparation technique and treated with fluorescent staining. The hair cells were observed under the confocal microscope. The control group was untreated. Results Half of the experimental group had hearing loss induced by kanamycin and furosemide (ABR threshold> 95 dB SPL). The cochlear outer hair cells of the guinea pigs showed

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Fast adaptation and Ca2+-sensitivity of the mechanotransducer require myosin-XVa in inner but not outer cochlear hair cells

    OpenAIRE

    Stepanyan, Ruben; Frolenkov, Gregory I.

    2009-01-01

    In inner ear hair cells, activation of mechotransduction channels is followed by extremely rapid deactivation that depends on the influx of Ca2+ through these channels. Although the molecular mechanisms of this “fast” adaptation are largely unknown, the predominant models assume Ca2+ sensitivity as an intrinsic property of yet unidentified mechanotransduction channels. Here we examined mechanotransduction in the hair cells of young postnatal shaker 2 mice (Myo15sh2/sh2). These mice have no fu...

  18. In search of the cochlear amplifier: New mechanical and molecular tools to probe transduction channel function

    Science.gov (United States)

    Karavitaki, K. Domenica; Indzhykulian, Artur A.; Zhang, Duan-Sun; Corey, David P.

    2015-12-01

    The study of mechanotransduction in cochlear hair cells requires stimulus methods that mimic the in-vivo stimulation. We have developed a new mechanical probe to better mimic the physiological stimulus delivered to cochlear hair cells through the overlying tectorial membrane. We combine these new probes with electroporation to study the contribution of different components of the transduction apparatus.

  19. Cochlear Implants

    Science.gov (United States)

    ... on this topic can be found in our Audiology Information Series [PDF]. How does a cochlear implant ... speech-language pathologists; speech, language, and hearing scientists; audiology and speech-language pathology support personnel; and students. ...

  20. Disruption of adaptor protein 2mu (AP-2mu) in cochlear hair cells impairs vesicle reloading of synaptic release sites and hearing

    NARCIS (Netherlands)

    Jung, S.; Maritzen, T.; Wichmann, C.; Jing, Z.; Neef, A.; Revelo, N.H.; Al-Moyed, H.; Meese, S.; Wojcik, S.M.; Panou, I.; Bulut, H.; Schu, P.; Ficner, R.; Reisinger, E.; Rizzoli, S.O.; Neef, J.; Strenzke, N.; Haucke, V.; Moser, T.

    2015-01-01

    Active zones (AZs) of inner hair cells (IHCs) indefatigably release hundreds of vesicles per second, requiring each release site to reload vesicles at tens per second. Here, we report that the endocytic adaptor protein 2mu (AP-2mu) is required for release site replenishment and hearing. We show that

  1. 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.

  2. 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.

  3. Cochlear Implants

    Science.gov (United States)

    ... an optimal period to develop speech and language skills. Research has shown that when these children receive a cochlear implant followed by intensive therapy before they are 18 months ... age develop language skills at a rate comparable to children with normal ...

  4. Cochlear implant

    Science.gov (United States)

    ... are sent along the auditory nerve to the brain. A deaf person does not have a functioning inner ear. A cochlear implant tries to replace the function of the inner ear by ... signals to the brain. Sound is picked up by a microphone worn ...

  5. 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.

  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. Cochlear implants

    OpenAIRE

    Despotović, Adrijana

    2011-01-01

    The aim of the thesis is to analyze the performance of the child with cochlear implant (CI) at language, math and movement activities. For the purpose of research exercises from all three above mentioned activities are prepared. Results of the exercises constitute the ground for the comparison of a child with CI and children with no hearing disability. Testing language skills was performed with exercises that included understanding, diction and identifying syllables. Mathematic skills...

  8. 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.

  9. Gain and frequency tuning within the mouse cochlear apex

    International Nuclear Information System (INIS)

    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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Time course of cochlear electrophysiology and morphology after combined administration of kanamycin and furosemide.

    OpenAIRE

    Versnel, H.; Agterberg, M.J.H.; de Groot, J. C. M. J.; Smoorenburg, G.F.; Klis, S.F.L.

    2007-01-01

    In animal models of deafness, administration of an aminoglycoside in combination with a loop diuretic is often applied to produce a rapid loss of cochlear hair cells. However, the extent to which surviving hair cells remain functional after such a deafening procedure varies. In a longitudinal electrocochleographical study, we investigated the variability of cochlear function between and within guinea pigs after combined administration of kanamycin and furosemide. Concurrently, histological da...

  15. Engraftment and Differentiation of Embryonic Stem Cell–Derived Neural Progenitor Cells in the Cochlear Nerve Trunk: Growth of Processes into the Organ of Corti

    OpenAIRE

    Corrales, C. Eduardo; Pan, Luying; Li, Huawei; Liberman, M. Charles; Heller, Stefan; Edge, Albert S. B.

    2006-01-01

    Hearing loss in mammals is irreversible because cochlear neurons and hair cells do not regenerate. To determine whether we could replace neurons lost to primary neuronal degeneration, we injected EYFP-expressing embryonic stem cell–derived mouse neural progenitor cells into the cochlear nerve trunk in immunosuppressed animals 1 week after destroying the cochlear nerve (spiral ganglion) cells while leaving hair cells intact by ouabain application to the round window at the base of the cochlea ...

  16. 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.

  17. 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 ...

  18. 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

  19. 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

  20. Time course of cochlear electrophysiology and morphology after combined administration of kanamycin and furosemide.

    NARCIS (Netherlands)

    Versnel, H.; Agterberg, M.J.H.; de Groot, J.C.M.J.; Smoorenburg, G.F.; Klis, S.F.L.

    2007-01-01

    In animal models of deafness, administration of an aminoglycoside in combination with a loop diuretic is often applied to produce a rapid loss of cochlear hair cells. However, the extent to which surviving hair cells remain functional after such a deafening procedure varies. In a longitudinal electr

  1. Structure and function of the hair cell ribbon synapse.

    OpenAIRE

    Nouvian, R.; Beutner, D.; Parsons, T D; Moser, T.

    2006-01-01

    Faithful information transfer at the hair cell afferent synapse requires synaptic transmission to be both reliable and temporally precise. The release of neurotransmitter must exhibit both rapid on and off kinetics to accurately follow acoustic stimuli with a periodicity of 1 ms or less. To ensure such remarkable temporal fidelity, the cochlear hair cell afferent synapse undoubtedly relies on unique cellular and molecular specializations. While the electron microscopy hallmark of the hair cel...

  2. 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

  3. Inhibition of caspases prevents ototoxic and ongoing hair cell death

    Science.gov (United States)

    Matsui, Jonathan I.; Ogilvie, Judith M.; Warchol, Mark E.

    2002-01-01

    Sensory hair cells die after acoustic trauma or ototoxic insults, but the signal transduction pathways that mediate hair cell death are not known. Here we identify several important signaling events that regulate the death of vestibular hair cells. Chick utricles were cultured in media supplemented with the ototoxic antibiotic neomycin and selected pharmacological agents that influence signaling molecules in cell death pathways. Hair cells that were treated with neomycin exhibited classically defined apoptotic morphologies such as condensed nuclei and fragmented DNA. Inhibition of protein synthesis (via treatment with cycloheximide) increased hair cell survival after treatment with neomycin, suggesting that hair cell death requires de novo protein synthesis. Finally, the inhibition of caspases promoted hair cell survival after neomycin treatment. Sensory hair cells in avian vestibular organs also undergo continual cell death and replacement throughout mature life. It is unclear whether the loss of hair cells stimulates the proliferation of supporting cells or whether the production of new cells triggers the death of hair cells. We examined the effects of caspase inhibition on spontaneous hair cell death in the chick utricle. Caspase inhibitors reduced the amount of ongoing hair cell death and ongoing supporting cell proliferation in a dose-dependent manner. In isolated sensory epithelia, however, caspase inhibitors did not affect supporting cell proliferation directly. Our data indicate that ongoing hair cell death stimulates supporting cell proliferation in the mature utricle.

  4. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the product. ...

  5. Hair transplantation.

    Science.gov (United States)

    Avram, Marc R

    2012-12-01

    Hair transplantation is a purely dermatologic surgical procedure that dermatologists should be able to perform in appropriate candidates with hair loss. Hair transplantation techniques performed in the 1960s through the 1990s utilized large grafts that created an unfortunate public image of unnatural-appearing transplanted hair. Over the last 15 years, hair transplantation has been performed using follicular units to create consistently natural-looking transplanted hair in both men and women. This article provides an overview of candidate selection and state-of-the-art techniques for performing hair transplantation. PMID:23409484

  6. Cochlear precursors of neural pitch and loudness codes.

    Science.gov (United States)

    Zwislocki, J J

    1995-09-01

    It has been believed by most auditory scientists for over a century that the place of maximum vibration in the cochlea provides the main pitch code. Recently, we have obtained experimental evidence showing that this is quite unlikely, because the maximum of cochlear excitation changes its location with sound intensity, moving over the useful sound intensity range toward the cochlear base by a distance equivalent to more than one octave, whereas the pitch remains almost constant. In the presence of outer hair cell damage, the maximum is shifted toward the base by a similar distance, whereas the pitch is hardly affected. Of interest, the location of the apical cutoff of excitation is practically unaffected by sound intensity or cochlear damage. For any given sound frequency, the shift of the maximum with sound intensity precludes any single cochlear location from coding for loudness over the entire useful intensity range. The code is very likely provided by the maximum, which changes its location with the intensity, or by the whole cochlear excitation area. Of significance in this respect is our determination that the growth of the output of the whole auditory nerve parallels the growth of the excitation area. These findings may be useful for the coding of sound in cochlear implants, as well as for hearing aid dynamics. PMID:7668600

  7. 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.

  8. The Olivocochlear Reflex Strength and Cochlear Sensitivity are Independently Modulated by Auditory Cortex Microstimulation

    OpenAIRE

    Dragicevic, Constantino D.; Aedo, Cristian; León, Alex; Bowen, Macarena; Jara, Natalia; Terreros, Gonzalo; Robles, Luis; Delano, Paul H.

    2015-01-01

    In mammals, efferent projections to the cochlear receptor are constituted by olivocochlear (OC) fibers that originate in the superior olivary complex. Medial and lateral OC neurons make synapses with outer hair cells and with auditory nerve fibers, respectively. In addition to the OC system, there are also descending projections from the auditory cortex that are directed towards the thalamus, inferior colliculus, cochlear nucleus, and superior olivary complex. Olivocochlear function can be as...

  9. Benefits and Risks of Cochlear Implants

    Science.gov (United States)

    ... and Medical Procedures Implants and Prosthetics Cochlear Implants Benefits and Risks of Cochlear Implants Share Tweet Linkedin ... the Use of Cochlear Implants What are the Benefits of Cochlear Implants? For people with implants: Hearing ...

  10. Feed-Forward and Feed-Backward Amplification Model from Cochlear Cytoarchitecture: An Interspecies Comparison

    OpenAIRE

    Yoon, Yong-Jin; Steele, Charles R.; Puria, Sunil

    2011-01-01

    The high sensitivity and wide bandwidth of mammalian hearing are thought to derive from an active process involving the somatic and hair-bundle motility of the thousands of outer hair cells uniquely found in mammalian cochleae. To better understand this, a biophysical three-dimensional cochlear fluid model was developed for gerbil, chinchilla, cat, and human, featuring an active “push-pull” cochlear amplifier mechanism based on the cytoarchitecture of the organ of Corti and using the time-ave...

  11. 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...

  12. Hair Transplants

    Science.gov (United States)

    ... Sweating Facial Redness Frown Lines and Forehead Furrows Hair Loss Sagging Skin Scars Skin Growths Skin Lesions Spider ... Sweating Facial Redness Frown Lines and Forehead Furrows Hair Loss Sagging Skin Scars Skin Growths Skin Lesions Spider ...

  13. 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.

  14. 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.

  15. 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

  16. Hair cosmetics

    OpenAIRE

    Nina Madnani; Kaleem Khan

    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, dr...

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

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

    OpenAIRE

    Chengfu Cai; Huawei Li

    2014-01-01

    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 h...

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

    OpenAIRE

    He, Yingzi; Cai, Chengfu; Tang, Dongmei; Sun, Shan; Li, Huawei

    2014-01-01

    In humans, auditory hair cells are not replaced when injured. Thus, cochlear hair cell loss causes progressive and permanent hearing loss. Conversely, non-mammalian 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 ...

  4. 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

  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 (level of the mechanoreceptors of the SCC. PMID:27448330

  6. Neural-Induced Human Mesenchymal Stem Cells Promote Cochlear Cell Regeneration in Deaf Guinea Pigs

    OpenAIRE

    Jang, Sujeong; Cho, Hyong-Ho; Kim, Song-Hee; Lee, Kyung-Hwa; Jun, Jae Yeoul; Park, Jong-Seong; Jeong, Han-Seong; Cho, Yong-Beom

    2015-01-01

    Objectives In mammals, cochlear hair cell loss is irreversible and may result in a permanent sensorineural hearing loss. Secondary to this hair cell loss, a progressive loss of spiral ganglion neurons (SGNs) is presented. In this study, we have investigated the effects of neural-induced human mesenchymal stem cells (NI-hMSCs) from human bone marrow on sensory neuronal regeneration from neomycin treated deafened guinea pig cochleae. Methods HMSCs were isolated from the bone marrow which was ob...

  7. 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.

  8. 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...

  9. The Cochlear Tuning Curve

    CERN Document Server

    Magnasco, M O

    2001-01-01

    The tuning curve of the cochlea measures how large an input is required to elicit a given output level as a function of the frequency. It is a fundamental object of auditory theory, for it summarizes how to infer what a sound was on the basis of the cochlear output. A simple model is presented showing that only two elements are sufficient for establishing the cochlear tuning curve: a broadly tuned traveling wave, moving unidirectionally from high to low frequencies, and a set of mechanosensors poised at the threshold of an oscillatory (Hopf) instability. These two components suffice to generate the various frequency-response regimes which are needed for a cochlear tuning curve with a high slope.

  10. 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

  11. 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...

  12. Hair Loss

    Science.gov (United States)

    ... 2 • 3 • 4 For Teens For Kids For Parents MORE ON THIS TOPIC Trichotillomania Dealing With a Health Condition Taking Care of Your Hair Skin, Hair, and Nails Body Image and Self-Esteem Alopecia: Kayla's Story Dealing With Cancer Contact Us ...

  13. The calcium-activated potassium channels of turtle hair cells

    OpenAIRE

    1995-01-01

    A major factor determining the electrical resonant frequency of turtle cochlear hair cells is the time course of the Ca-activated K current (Art, J. J., and R. Fettiplace. 1987. Journal of Physiology. 385:207- 242). We have examined the notion that this time course is dictated by the K channel kinetics by recording single Ca-activated K channels in inside-out patches from isolated cells. A hair cell's resonant frequency was estimated from its known correlation with the dimensions of the hair ...

  14. 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...... 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...

  15. Hair Removal

    DEFF Research Database (Denmark)

    Hædersdal, Merete

    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 ...... treatment procedures are evolving. Consumer-based treatments with portable home devices are rapidly evolving, and presently include low-level diode lasers and IPL devices....... 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...... systems. Evidence has been found for long-term hair removal efficacy beyond 6 months after repetitive treatments with alexandrite, diode, and long-pulse Nd:YAG lasers, whereas the current long-term evidence is sparse for IPL devices. Treatment parameters must be adjusted to patient skin type...

  16. 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.

  17. Einstein Hair

    CERN Document Server

    Kolyvaris, Theodoros; Papantonopoulos, Eleftherios; Siopsis, George

    2011-01-01

    We consider a gravitating system of vanishing cosmological constant consisting of an electromagnetic field and a scalar field coupled to the Einstein tensor. A Reissner-Nordstr{\\o}m black hole undergoes a second-order phase transition to a hairy black hole of generally anisotropic hair at a certain critical temperature which we compute. The no-hair theorem is evaded due to the coupling between the scalar field and the Einstein tensor ("Einstein hair"). We calculate explicitly the properties of a hairy black hole configuration near the critical temperature and show that it is energetically favorable over the corresponding Reissner-Nordstr{\\o}m black hole.

  18. 压力波对豚鼠耳蜗血管纹、毛细胞心钠素免疫活性改变的研究%Change of Atrial Natriuretic Peptides Immunoreactivity in Stria Vascularis and Hair Cells of Cochlear and Correlation Study of Auditory Threshold Shift After Shock Wave

    Institute of Scientific and Technical Information of China (English)

    陈合新; 邱建华; 王锦玲

    2000-01-01

    目的为探讨压力波的致聋机理,对豚鼠耳蜗血管纹(SV)、毛细胞(HC)中心钠素免疫活性(ANP-IR)的改变及与听阈阈移的相关性进行研究。方法采用免疫细胞化学(ABC法)法、图像分析听性脑干反应测听技术(ABR)对压力波暴露后不同时间分组的豚鼠耳蜗SV、HC中ANP-IR产物进行检测。结果压力波暴露后6、12、24h和48h组SV组织中ANP-IR光密度值较对照组均有明显的差异(P<0.05),其中24h组最高;冲击波暴露后6、12、24h组内毛细胞(IHC)中ANP-IR阳性产物的光密度值较对照组明显增高(P<0.05),其中以12 h组最高。二者的变化均与听阈阈移有明显的正相关性(r1=0.8175,P>0.05;r2=0.9185,P>0.05)。而外毛细胞(OHC)中ANP-IR阳性产物变化不明显。结论压力波暴露后,SV组织中ANP的增高可能是内耳的一种代偿机制;IHC和OHC中ANP-IR的变化可能是冲击波对其损伤机制的不同表现。%Objective In order to investigate the effects of shock wave on atrial natriuretic peptides immunoreactivity in the stria vascularis and hair cells of cochlear and correlation of auditory threshold shift,to study the mechanism of deafness caused by blast trauma. Methods After shock wave, different groups of guinea pigs were studied by ABC immunohistochemistry, image analysis and auditory brainstem response. Results ANP - IR optic density in experimental group was higher than that of control in the stria vascularis and inner hair cells. The change of ANP- IR optic density was directy correlated with ABR threshold shift (r2 =0.9185. P2<0.05). There was no change of ABR and ANP - IR optic density on outer hair cells. Conclusion The change of ANP in the stria vascularis may be a compensatory mechanism to heating lose caused by shock wave; ANP in inner cells may be a pathological manifestation of shock wave. The changes of ANP - IR in outer cells may be a false appearance, it was the shock wave which

  19. 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.

  20. Hair Loss

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases Cosmetic treatments Dry / sweaty skin Eczema / dermatitis Hair and scalp ...

  1. Your Hair

    Science.gov (United States)

    ... warm and provides a little cushioning for your skull. Eyelashes protect your eyes by decreasing the amount ... Colors What kind of hair do you have — black and curly, blond and straight, or some other ...

  2. 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.

  3. 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...

  4. 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...

  5. Medial olivocochlear efferent inhibition of basilar-membrane responses to clicks: Evidence for two modes of cochlear mechanical excitation

    OpenAIRE

    Guinan, John J.; Cooper, Nigel P.

    2008-01-01

    Conceptualizations of mammalian cochlear mechanics are based on basilar-membrane (BM) traveling waves that scale with frequency along the length of the cochlea, are amplified by outer hair cells (OHCs), and excite inner hair cells and auditory-nerve (AN) fibers in a simple way. However, recent experimental work has shown medial-olivocochlear (MOC) inhibition of AN responses to clicks that do not fit with this picture. To test whether this AN-initial-peak (ANIP) inhibition might result from hi...

  6. ACF7 Is a Hair-Bundle Antecedent, Positioned to Integrate Cuticular Plate Actin and Somatic Tubulin

    OpenAIRE

    Antonellis, Patrick J.; Pollock, Lana M.; Chou, Shih-Wei; Hassan, Ahmed; Geng, Ruishuang; Chen, Xi; Fuchs, Elaine; Alagramam, Kumar N.; Auer, Manfred; McDermott, Brian M., Jr.

    2014-01-01

    The precise morphology of the mechanosensitive hair bundle requires seamless integration of actin and microtubule networks. Here, we identify Acf7a (actin crosslinking family protein 7a) as a protein positioned to bridge these distinct cytoskeletal networks in hair cells. By imaging Acf7a–Citrine fusion protein in zebrafish and immunolabeling of vestibular and cochlear mouse hair cells, we show that Acf7a and ACF7 circumscribe, underlie, and are interwoven into the cuticular plate (CP), and t...

  7. [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.

  8. 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.

  9. Ototoxicity of paclitaxel in rat cochlear organotypic cultures

    International Nuclear Information System (INIS)

    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

  10. [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.

  11. The retinoblastoma gene pathway regulates the postmitotic state of hair cells of the mouse inner ear

    OpenAIRE

    Mantela, Johanna; Jiang, Zhe; Ylikoski, Jukka; Fritzsch, Bernd; Zacksenhaus, Eldad; Pirvola, Ulla

    2005-01-01

    Precursors of cochlear and vestibular hair cells of the inner ear exit the cell cycle at midgestation. Hair cells are mitotically quiescent during late-embryonic differentiation stages and postnatally. We show here that the retinoblastoma gene Rb and the encoded protein pRb are expressed in differentiating and mature hair cells. In addition to Rb, the cyclin dependent kinase inhibitor (CKI) p21 is expressed in developing hair cells, suggesting that p21 is an upstream effector of pRb activity....

  12. Hair Cell Overexpression of Islet1 Reduces Age-Related and Noise-Induced Hearing Loss

    OpenAIRE

    Huang, Mingqian; Kantardzhieva, Albena; Scheffer, Deborah; Liberman, M. Charles; Chen, Zheng-Yi

    2013-01-01

    Isl1 is a LIM-homeodomain transcription factor that is critical in the development and differentiation of multiple tissues. In the mouse inner ear, Isl1 is expressed in the prosensory region of otocyst, in young hair cells and supporting cells, and is no longer expressed in postnatal auditory hair cells. To evaluate how continuous Isl1 expression in postnatal hair cells affects hair cell development and cochlear function, we created a transgenic mouse model in which the Pou4f3 promoter drives...

  13. 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.

  14. 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

  15. 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.

  16. Body Hair

    Science.gov (United States)

    ... and uncomfortable. If you decide to use a hair-removal cream, make sure it says it’s gentle enough for the pubic area. Don’t put on any product that could sting, like aftershave lotion. To help avoid irritation, don’t use products with added dyes or fragrances. If you have more questions about ...

  17. 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

  18. Hair cell and organ of corti responses to normal and intense acoustic stimulation

    OpenAIRE

    Fridberger, Anders

    1997-01-01

    The principal aims of the studies described in this thesis were to develop an in vitro model for studying acoustic overstimulation at the cellular level, to define the electrical and mechanical response characteristics of the perfused temporal bone preparation, and to investigate the effects of intense sound stimulation on the calcium levels of the hair cells in the intact hearing organ. In the in vitro model for acoustic overstimulation, isolated cochlear outer hair cells ...

  19. Developmental segregation in the afferent projections to mammalian auditory hair cells.

    OpenAIRE

    Echteler, S M

    1992-01-01

    The mammalian ear contains two types of auditory receptors, inner and outer hair cells, that lie in close proximity to each other within the sensory epithelium of the cochlea. In adult mammals, these two classes of auditory hair cells are innervated by separate populations of afferent neurons that differ strikingly in their cellular morphology and their pattern of arborization within the cochlea. At present, it is unclear when or how these distinctive patterns of cochlear innervation emerge a...

  20. 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 (

  1. 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.

  2. 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 temporal...... patterns from a Diagnostic Rhyme Test (DRT) were measured and analyzed in terms of acoustic-phonetic features. This was done for three listeners with cochlear hearing loss and at two signal-to-noise ratios. It is shown that the predicted errors patterns matched the measured patterns in most conditions......, such as the evaluation of hearing-instrument signal processing, where the effects of specific processing strategies can be simulated for individual hearing losses....

  3. 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.

  4. 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. PMID:26370650

  5. Micropipette aspiration on the outer hair cell lateral wall.

    OpenAIRE

    Sit, P S; Spector, A A; Lue, A J; Popel, A S; Brownell, W.E.

    1997-01-01

    The mechanical properties of the lateral wall of the guinea pig cochlear outer hair cell were studied using the micropipette aspiration technique. A fire-polished micropipette with an inner diameter of approximately 4 microm was brought into contact with the lateral wall and negative pressure was applied. The resulting deformation of the lateral wall was recorded on videotape and subjected to morphometric analysis. The relation between the length of the aspirated portion of the cell and aspir...

  6. Skin, Hair, and Nails

    Science.gov (United States)

    ... distribution of melanin in the cortex of each hair (the same melanin that's found in the epidermis). Hair also contains ... red pigment; people who have blonde or red hair have only a small amount of melanin in their hair. Hair becomes gray when people ...

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

    DEFF Research Database (Denmark)

    Jensen, Jane Bjerg; Lysaght, Andrew C; Liberman, M Charles;

    2015-01-01

    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...... 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...

  8. Developmental Neuroplasticity After Cochlear Implantation

    OpenAIRE

    Kral, Andrej; Sharma, Anu

    2011-01-01

    Cortical development is dependent on stimulus-driven learning. The absence of sensory input from birth, as occurs in congenital deafness, affects normal growth and connectivity needed to form a functional sensory system—resulting in deficits in oral language learning. Cochlear implants bypass cochlear damage by directly stimulating the auditory nerve and brain, making it possible to avoid many of the deleterious effects of sensory deprivation. Congenitally deaf animals and children who receiv...

  9. 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.

  10. Laser Hair Removal

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Hair Removal, Laser A A A AFTER: Two laser hair removal treatments were performed. This picture is ... Procedure Overview With just the right type of laser or Intense Pulsed Light (IPL) technology, suitable hairs ...

  11. Hair spray poisoning

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002705.htm Hair spray poisoning To use the sharing features on this page, please enable JavaScript. Hair spray poisoning occurs when someone breathes in (inhales) hair ...

  12. Supporting cells eliminate dying sensory hair cells to maintain epithelial integrity in the avian inner ear

    OpenAIRE

    Bird, Jonathan E.; Daudet, Nicolas; Mark E Warchol; Gale, Jonathan E.

    2010-01-01

    Epithelial homeostasis is essential for sensory transduction in the auditory and vestibular organs of the inner ear, but how it is maintained during trauma is poorly understood. To examine potential repair mechanisms, we expressed β-actin-EGFP in the chick inner ear and used live-cell imaging to study how sensory epithelia responded during aminoglycoside-induced hair cell trauma. We found that glial-like supporting cells used two independent mechanisms to rapidly eliminate dying hair cells. S...

  13. Recovery of vestibular function following hair cell destruction by streptomycin

    Science.gov (United States)

    Jones, T. A.; Nelson, R. C.

    1992-01-01

    Can the vestibular periphery of warm-blooded vertebrates recover functionally from severe sensory hair cell loss? Recent findings in birds suggest a mechanism for recovery but in fact no direct functional evidence has been reported. We produced vestibular hair cell lesions using the ototoxic agent streptomycin sulfate (600 mg/kg/day, 8 days, chicks, Gallus domesticus). Compound action potentials of the vestibular nerve were used as a direct measure of peripheral vestibular function. Vestibular thresholds, neural activation latencies and amplitudes were documented. Eight days of drug treatment elevated thresholds significantly (P morphologies including activation latencies and amplitudes required an additional 6-8 weeks.

  14. 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 ...

  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. Type II Cochlear Ganglion Neurons Do Not Drive the Olivocochlear Reflex: Re-Examination of the Cochlear Phenotype in Peripherin Knock-Out Mice

    Science.gov (United States)

    2016-01-01

    Abstract The cochlear nerve includes a small population of unmyelinated sensory fibers connecting outer hair cells to the brain. The functional role of these type II afferent neurons is controversial, because neurophysiological data are sparse. A recent study (Froud et al., 2015) reported that targeted deletion of peripherin, a type of neurofilament, eliminated type II afferents and inactivated efferent feedback to the outer hair cells, thereby suggesting that type II afferents were the sensory drive to this sound-evoked, negative-feedback reflex, the olivocochlear pathway. Here, we re-evaluated the cochlear phenotype in mice from the peripherin knock-out line and show that (1) type II afferent terminals are present in normal number and (2) olivocochlear suppression of cochlear responses is absent even when this efferent pathway is directly activated by shocks. We conclude that type II neurons are not the sensory drive for the efferent reflex and that peripherin deletion likely causes dysfunction of synaptic transmission between olivocochlear terminals and their peripheral targets. PMID:27570826

  17. Significance of chick quality score in broiler production

    OpenAIRE

    Ven, van de, J.; Wagenberg, van, A.V.; Uitdehaag, K.A.; Groot Koerkamp, P.W.G.; Kemp, B; Brand, van den, MGJ Mark

    2012-01-01

    The quality of day old chicks is crucial for profitable broiler production, but a difficult trait to define. In research, both qualitative and quantitative measures are used with variable predictive value for subsequent performance. In hatchery practice, chick quality is judged on a binomial scale, as chicks are divided into first grade (Q1-saleable) and second grade (Q2) chicks right after hatch. Incidences and reasons for classifying chicks as Q2, and potential of these chicks for survival ...

  18. 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.

  19. Delayed loss of hearing after hearing preservation cochlear implantation: Human temporal bone pathology and implications for etiology.

    Science.gov (United States)

    Quesnel, Alicia M; Nakajima, Hideko Heidi; Rosowski, John J; Hansen, Marlan R; Gantz, Bruce J; Nadol, Joseph B

    2016-03-01

    After initially successful preservation of residual hearing with cochlear implantation, some patients experience subsequent delayed hearing loss. The etiology of such delayed hearing loss is unknown. Human temporal bone pathology is critically important in investigating the etiology, and directing future efforts to maximize long term hearing preservation in cochlear implant patients. Here we present the temporal bone pathology from a patient implanted during life with an Iowa/Nucleus Hybrid S8 implant, with initially preserved residual hearing and subsequent hearing loss. Both temporal bones were removed for histologic processing and evaluated. Complete clinical and audiologic records were available. He had bilateral symmetric high frequency severe to profound hearing loss prior to implantation. Since he was implanted unilaterally, the unimplanted ear was presumed to be representative of the pre-implantation pathology related to his hearing loss. The implanted and contralateral unimplanted temporal bones both showed complete degeneration of inner hair cells and outer hair cells in the basal half of the cochleae, and only mild patchy loss of inner hair cells and outer hair cells in the apical half. The total spiral ganglion neuron counts were similar in both ears: 15,138 (56% of normal for age) in the unimplanted right ear and 13,722 (51% of normal for age) in the implanted left ear. In the basal turn of the implanted left cochlea, loose fibrous tissue and new bone formation filled the scala tympani, and part of the scala vestibuli. Delayed loss of initially preserved hearing after cochlear implantation was not explained by additional post-implantation degeneration of hair cells or spiral ganglion neurons in this patient. Decreased compliance at the round window and increased damping in the scala tympani due to intracochlear fibrosis and new bone formation might explain part of the post-implantation hearing loss. Reduction of the inflammatory and immune response to

  20. Developmental neuroplasticity after cochlear implantation.

    Science.gov (United States)

    Kral, Andrej; Sharma, Anu

    2012-02-01

    Cortical development is dependent on stimulus-driven learning. The absence of sensory input from birth, as occurs in congenital deafness, affects normal growth and connectivity needed to form a functional sensory system, resulting in deficits in oral language learning. Cochlear implants bypass cochlear damage by directly stimulating the auditory nerve and brain, making it possible to avoid many of the deleterious effects of sensory deprivation. Congenitally deaf animals and children who receive implants provide a platform to examine the characteristics of cortical plasticity in the auditory system. In this review, we discuss the existence of time limits for, and mechanistic constraints on, sensitive periods for cochlear implantation and describe the effects of multimodal and cognitive reorganization that result from long-term auditory deprivation. PMID:22104561

  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. Microengineered hydromechanical cochlear model

    Science.gov (United States)

    White, Robert D.; Grosh, Karl

    2005-01-01

    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 π 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. PMID:15665089

  3. 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.

  4. 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. PMID:25878443

  5. Numb is not a critical regulator of Notch-mediated cell fate decisions in the developing chick inner ear

    Directory of Open Access Journals (Sweden)

    Mark eEddison

    2015-03-01

    Full Text Available The Notch signalling pathway controls differentiation of hair cells and supporting cells in the vertebrate inner ear. Here, we have investigated whether Numb, a known regulator of Notch activity in Drosophila, is involved in this process in the embryonic chick. The chicken homologue of Numb is expressed throughout the otocyst at early stages of development and is concentrated at the basal pole of the cells. It is asymmetrically allocated at some cell divisions, as in Drosophila, suggesting that it could act as a determinant inherited by one of the two daughter cells and favouring adoption of a hair-cell fate. To test the implication of Numb in hair cell fate decisions and the regulation of Notch signalling, we used different methods to overexpress Numb at different stages of inner ear development. We found that sustained or late Numb overexpression does not promote hair cell differentiation, and Numb does not prevent the reception of Notch signalling. Surprisingly, none of the Numb-overexpressing cells differentiated into hair cells, suggesting that high levels of Numb protein could interfere with intracellular processes essential for hair cell survival. However when Numb was overexpressed early and more transiently during ear development, no effect on hair cell formation was seen. These results suggest that in the inner ear at least, Numb does not significantly repress Notch activity and that its asymmetric distribution in dividing precursor cells does not govern the choice between hair cell and supporting cell fates.

  6. Pediatric cochlear implantation: an update.

    Science.gov (United States)

    Vincenti, Vincenzo; Bacciu, Andrea; Guida, Maurizio; Marra, Francesca; Bertoldi, Barbara; Bacciu, Salvatore; Pasanisi, Enrico

    2014-01-01

    Deafness in pediatric age can adversely impact language acquisition as well as educational and social-emotional development. Once diagnosed, hearing loss should be rehabilitated early; the goal is to provide the child with maximum access to the acoustic features of speech within a listening range that is safe and comfortable. In presence of severe to profound deafness, benefit from auditory amplification cannot be enough to allow a proper language development. Cochlear implants are partially implantable electronic devices designed to provide profoundly deafened patients with hearing sensitivity within the speech range. Since their introduction more than 30 years ago, cochlear implants have improved their performance to the extent that are now considered to be standard of care in the treatment of children with severe to profound deafness. Over the years patient candidacy has been expanded and the criteria for implantation continue to evolve within the paediatric population. The minimum age for implantation has progressively reduced; it has been recognized that implantation at a very early age (12-18 months) provides children with the best outcomes, taking advantage of sensitive periods of auditory development. Bilateral implantation offers a better sound localization, as well as a superior ability to understand speech in noisy environments than unilateral cochlear implant. Deafened children with special clinical situations, including inner ear malformation, cochlear nerve deficiency, cochlear ossification, and additional disabilities can be successfully treated, even thogh they require an individualized candidacy evaluation and a complex post-implantation rehabilitation. Benefits from cochlear implantation include not only better abilities to hear and to develop speech and language skills, but also improved academic attainment, improved quality of life, and better employment status. Cochlear implants permit deaf people to hear, but they have a long way to go before

  7. 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.

  8. [Hair and their environment].

    Science.gov (United States)

    Piérard-Franchimont, C; Piérard, G E

    2015-02-01

    Hair is influenced by the effects of the daily environment. Some toxic xenobiotics slow down or block the cell renewal of the hair matrix, thus inhibiting hair growth. The ultraviolet light obviously influences the physical structure and physiology of the hair follicle. Tobacco is similarly responsible for negative influences on the evolution of various alopecias. Several cosmetic procedures for maintaining and making hair more attractive are not always harmless, and they occasionally represent a possible origin for alopecia. PMID:26011990

  9. Hair Cosmetics: An Overview

    OpenAIRE

    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 tr...

  10. 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.

  11. 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.

  12. 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...

  13. 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

  14. 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.

  15. 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.

  16. 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.

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

    Science.gov (United States)

    Wang, Yanli; Puria, Sunil; Steele, Charles

    2015-12-01

    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.

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

    International Nuclear Information System (INIS)

    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

  19. Evidence for Outer Hair Cell Driven Oscillatory Fluid Flow in the Tunnel of Corti

    Science.gov (United States)

    Karavitaki, K. Domenica; Mountain, David C.

    2007-01-01

    Outer hair cell (OHC) somatic motility plays a key role in mammalian cochlear frequency selectivity and hearing sensitivity, but the mechanism of cochlear amplification is not well understood and remains a matter of controversy. We have visualized and quantified the effects of electrically evoked OHC somatic motility within the gerbil organ of Corti using an excised cochlear preparation. We found that OHC motility induces oscillatory motion of the medial olivocochlear fibers where they cross the tunnel of Corti (ToC) in their course to innervate the OHCs. We show that this motion is present at physiologically relevant frequencies and remains at locations distal to the OHC excitation point. We interpret this fiber motion to be the result of oscillatory fluid flow in the ToC. We show, using a simple one-dimensional hydromechanical model of the ToC, that a fluid wave within the tunnel can travel without significant attenuation for distances larger than the wavelength of the cochlear traveling wave at its peak. This ToC fluid wave could interact with the cochlear traveling wave to amplify the motion of the basilar membrane. The ToC wave could also provide longitudinal coupling between adjacent sections of the basilar membrane, and such coupling may be critical for cochlear amplification. PMID:17277193

  20. Diversity in cochlear morphology and its influence on cochlear implant electrode position

    NARCIS (Netherlands)

    Marel, K.S. van der; Briaire, J.J.; Wolterbeek, R..; Snel-Bongers, J.; Verbist, B.M.; Frijns, J.H.

    2014-01-01

    To define a minimal set of descriptive parameters for cochlear morphology and study its influence on the cochlear implant electrode position in relation to surgical insertion distance.Cochlear morphology and electrode position were analyzed using multiplanar reconstructions of the pre- and postopera

  1. 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

  2. Distinguishing hair cell from neural potentials recorded at the round window.

    Science.gov (United States)

    Forgues, Mathieu; Koehn, Heather A; Dunnon, Askia K; Pulver, Stephen H; Buchman, Craig A; Adunka, Oliver F; Fitzpatrick, Douglas C

    2014-02-01

    Almost all patients who receive cochlear implants have some acoustic hearing prior to surgery. Electrocochleography (ECoG), or electrophysiological measures of cochlear response to sound, can identify remaining auditory nerve activity that is the basis for this residual hearing and can record potentials from hair cells that are no longer functionally connected to nerve fibers. The ECoG signal is therefore complex, being composed of both hair cell and neural signals. To identify signatures of different sources in the recorded potentials, we collected ECoG data across frequency and intensity from the round window of gerbils before and after treatment with kainic acid, a neurotoxin. Distortions in the recorded waveforms were produced by different sources over different ranges of frequency and intensity. In response to tones at low frequencies and low-to-moderate intensities, the major source of distortion was from neural phase-locking that was sensitive to kainic acid. At high intensities at all frequencies, the distortion was not sensitive to kainic acid and was consistent with asymmetric saturation of the hair cell transducer current. In addition to loss of phase-locking, changes in the envelope after kainic acid treatment indicate that sustained neural firing combines with receptor potentials from hair cells to produce the envelope of the response to tones. These results provide baseline data to interpret comparable recordings from human cochlear implant recipients. PMID:24133227

  3. Hair Loss (Alopecia)

    Science.gov (United States)

    ... Eating disorder: When a person has an eating disorder, hair loss is common. Anorexia (not eating enough) and bulimia (vomiting after eating) can cause hair loss. Medicine Some prescription medicines can cause ...

  4. Hair Loss (Alopecia Areata)

    Science.gov (United States)

    ... rash and rashes clinical tools newsletter | contact Share | Hair Loss (Alopecia Areata) Information for adults A A A This ... scalp with a round area of non-scarring hair loss typical of alopecia areata. Overview Alopecia areata is ...

  5. Hair Treatments and Pregnancy

    Science.gov (United States)

    ... coloring/dye through my skin? Low levels of hair dye can be absorbed through the skin after application, ... am pregnant? There are very few studies of hair dye use during human pregnancy. In animal studies, at ...

  6. Intravenous administration of bone marrow mononuclear cells alleviates hearing loss after transient cochlear ischemia through paracrine effects.

    Science.gov (United States)

    Takagi, Taro; Yoshida, Tadashi; Okada, Masahiro; Hata, Ryuji; Hato, Naohito; Gyo, Kiyofumi; Hakuba, Nobuhiro

    2014-05-16

    Bone marrow mononuclear cells (BMMCs) are known to enhance recovery from ischemic insults by secreting angiogenic factors and inducing the expression of angiogenic factors from host tissues. Therefore, the transplantation of BMMCs is considered a potential approach to promoting the repair of ischemic damaged organs. Here, we investigated the influence of BMMCs on progressive hair cell degeneration after transient cochlear ischemia in gerbils. Transient cochlear ischemia was produced by extracranial occlusion of the bilateral vertebral arteries immediately before their entry into the transverse foramen of the cervical vertebra. An intravenous injection of BMMCs prevented ischemia-induced hair cell degeneration and ameliorated hearing impairment. A tracking study showed that BMMCs injected into the femoral vein were limited in the spiral artery of the cochlea, suggesting that, although transplanted BMMCs were retained within the spiral ganglion area of the cochlea, they were neither transdifferentiated into cochlear cells nor fused with the injured hair cells and supporting cells in the organ of Corti to restore their functions. We also showed that the protein level of neurotrophin-3 and glial cell line-derived neurotrophic factor in the organ of Corti was upregulated after treatment with BMMCs. These results suggested that BMMCs have therapeutic potential possibly through paracrine effects. Thus, we propose the use of BMMCs as a potential new therapeutic strategy for hearing loss. PMID:24840930

  7. 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.

  8. The inferior cochlear vein: surgical aspects in cochlear implantation.

    Science.gov (United States)

    Guo, Rui; Zhang, HongLei; Chen, Wei; Zhu, XiaoQuan; Liu, Wei; Rask-Andersen, Helge

    2016-02-01

    The patency of the inferior cochlear vein (ICV) may be challenged in cochlear implantation (CI) due to its location near the round window (RW). This may be essential to consider during selection of different trajectories for electrode insertion aiming at preserving residual hearing. Venous blood from the human cochlea is drained through the ICV. The vein also drains blood from the modiolus containing the spiral ganglion neurons. Surgical interference with this vein could cause neural damage influencing CI outcome. We analyzed the topographical relationship between the RW and ICV bony channel and cochlear aqueduct (CA) from a surgical standpoint. Archival human temporal bones were further microdissected to visualize the CA and its accessory canals (AC1 and AC2). This was combined with examinations of plastic and silicone molds of the human labyrinth. Metric analyses were made using photo stereomicroscopy documenting the proximal portion of the AC1, the internal aperture of the CA and the RW. The mean distance between the AC1 and the anterior rim of the RW was 0.81 mm in bone specimens and 0.67 mm assessed in corrosion casts. The AC1 runs from the floor of the scala tympani through the otic capsule passing parallel to the CA to the posterior cranial fossa. The mean distance between the CA and AC1 canal was 0.31 and 0.25 mm, respectively. PMID:25700831

  9. Bubble Hair and Other Acquired Hair Shaft Anomalies due to Hot Ironing on Wet Hair

    OpenAIRE

    Savitha, AS; S Sacchidanand; Revathy, TN

    2011-01-01

    Bubble hair is an acquired hair shaft abnormality characterized by multiple airfilled spaces within the hair shaft. It is a result of thermal injury. We report a classic case of 22-year-old female who complained of dry brittle hair of two-week duration. Patient had used hot iron on wet hair twice to straighten hair. Hair microscopy was diagnostic and showed multiple air-filled spaces within the hair shaft.

  10. Consequences of outer hair cell damage for otoacoustic emissions and audio-vocal feedback in the mustached bat.

    Science.gov (United States)

    Kössl, M; Vater, M

    2000-12-01

    The cochlea of the mustached bat is adapted to process ultrasonic echolocation signals. To assess the involvement of active sound amplification by outer hair cells in high-frequency hearing and in audio-vocal interaction, selective hair cell damage was induced by the antibiotic Amikacin. Amikacin preferentially damaged the first row of outer hair cells in the basal cochlear turn. The cochlear regions coding for the second-harmonic constant-frequency component of the echolocation call (CF2) at 61 kHz and for frequencies between 75 and 100 kHz were the most affected. This was reflected in an increase of mechanical thresholds obtained by measuring distortion-product otoacoustic emissions. During initial periods of minor hair cell damage, when thresholds had deteriorated by less than 40 dB, a sharp, mechanical, cochlear resonance that is responsible for enhanced tuning to 61 kHz was still measurable as a stimulus-frequency otoacoustic emission and its frequency decreased by 350 Hz. The persistence of the resonance suggests that passive structures like the tectorial or basilar membrane are important for generation of the resonance. Behaviorally, the bats reacted to the change in cochlear micromechanics with a decrease of their CF2 frequency by 360 Hz. After larger hair cell damage, when the cochlear resonance had disappeared, the bats vocalized only sparsely and the CF2 frequency increased by up to 2 kHz, which may correspond to a state without audiovocal feedback. This indicates that audio-vocal feedback in the nondamaged animal works to lower the call frequency. PMID:11547810

  11. Hair transplantation surgery

    OpenAIRE

    Khanna Manoj

    2008-01-01

    Techniques in hair transplantation have evolved recently which make results look more natural. Hair restoration is one of the most exciting and innovative surgical fields in aesthetic surgery today. A precise appreciation of anatomy has allowed the use of follicular unit grafts. With better methods of harvesting and implantation, hair transplantation results represent a blend of art and science.

  12. Hair transplantation update.

    Science.gov (United States)

    Rogers, Nicole E

    2015-06-01

    Contemporary hair transplant surgery offers results that are natural and undetectable. It is an excellent treatment option for male and female pattern hair loss. Patients are encouraged to also use medical therapy to help protect their surgical results and prevent ongoing thinning of the surrounding hairs. The two major techniques of donor elliptical harvesting and follicular unit extraction are discussed here. PMID:26176286

  13. Hair tourniquet syndrome

    Directory of Open Access Journals (Sweden)

    Bangroo A

    2005-01-01

    Full Text Available A frequently unrecognized and potentially devastating form of penile strangulation is that caused by human hair. Hair tourniquet syndrome frequently occurs during the time period when post partum mothers are experiencing increased hair loss. The majority of cases are thought to be accidental, however possibility of child abuse should be considered in every case.

  14. 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?

  15. 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.

  16. Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds

    Science.gov (United States)

    Boyle, Richard; Highstein, Stephen M.; Carey, John P.; Xu, Jinping

    2002-01-01

    Streptomycin sulfate (1.2 g/kg i.m.) was administered for 5 consecutive days to 5-7-day-old white Leghorn chicks; this causes damage to semicircular canal hair cells that ultimately regenerate to reform the sensory epithelium. During the recovery period, electrophysiological recordings were taken sequentially from anterior semicircular canal primary afferents using an indentation stimulus of the canal that has been shown to mimic rotational stimulation. Chicks were assigned to an early (14-18 days; n = 8), intermediate (28-34 days; n = 5), and late (38-58 days; n = 4) period based on days after treatment. Seven untreated chicks, 15-67 days old, provided control data. An absence of background and indent-induced discharge was the prominent feature of afferents in the early period: only "silent" afferents were encountered in 5/8 experiments. In several of these chicks, fascicles of afferent fibers were seen extending up to the epithelium that was void of hair cells, and intra- and extracellular biocytin labeling revealed afferent processes penetrating into the supporting cell layer of the crista. In 3/8 chicks 74 afferents could be characterized, and they significantly differed from controls (n = 130) by having a lower discharge rate and a negligible response to canal stimulation. In the intermediate period there was considerable variability in discharge properties of 121 afferents, but as a whole the number of "silent" fibers in the canal nerve diminished, the background rate increased, and a response to canal stimulation detected. Individually biocytin-labeled afferents had normal-appearing terminal specializations in the sensory epithelium by 28 days poststreptomycin. In the late period, afferents (n = 58) remained significantly different from controls in background discharge properties and response gain. The evidence suggests that a considerable amount of variability exists between chicks in the return of vestibular afferent function following ototoxic injury and

  17. Cochlear Implants and Brain Plasticity

    OpenAIRE

    Fallon, James B.; Irvine, Dexter R. F.; Shepherd, Robert K.

    2002-01-01

    Cochlear implants have been implanted in over 110,000 deaf adults and children worldwide and provide these patients with important auditory cues necessary for auditory awareness and speech perception via electrical stimulation of the auditory nerve (AN). In 1942 Woolsey & Walzl presented the first report of cortical responses to localised electrical stimulation of different sectors of the AN in normal hearing cats, and established the cochleotopic organization of the projections to primary au...

  18. Radioactivation analysis of hair

    International Nuclear Information System (INIS)

    With the aim of indicating environmental pollution effects by heavy metals on humans using hair, nondestructive activation analysis was applied to 382 normal Japanese hair samples (background level). Elemental contents of hair could be determined for Ag, Al, As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, I, K, La, Mg, Mn, Na, S, Sb, Sc, Se, Sm, Ti, V and Zn. As these elements in hair have wide concentration ranges, the differences in concentration distribution between groups (sex, age, permanent treatment and regional difference) are discussed. A method for hair sampling is presented. (author)

  19. Molecular anatomy and physiology of exocytosis in sensory hair cells.

    Science.gov (United States)

    Rutherford, Mark A; Pangršič, Tina

    2012-01-01

    Hair cells mediate our senses of hearing and balance by synaptic release of glutamate from somatic active zones (AZs). They share conserved mechanisms of exocytosis with neurons and other secretory cells of diverse form and function. Concurrently, AZs of these neuro-epithelial hair cells employ several processes that differ remarkably from those of neuronal synaptic terminals of the brain. Their unique molecular anatomy enables them to better respond to small, graded changes in membrane potential and to produce unsurpassed rates of exocytosis. Here, we focus on the AZs of cochlear inner hair cells (IHCs). As in other hair cells, these AZs are occupied by a cytoplasmic extension of the presynaptic density, called the synaptic ribbon: a specialized protein complex required for normal physiological function. Some proteins found at IHC synapses are uniquely expressed or enriched there, where their disruption can beget deafness in humans and in animal models. Other proteins, essential for regulation of conventional neuronal Ca(2+)-triggered fusion, are apparently absent from IHCs. Certain common synaptic proteins appear to have extra significance at ribbon-type AZs because of their interactions with unique molecules, their unusual concentrations, or their atypical localization and regulation. We summarize the molecular-anatomical specializations that underlie the unique synaptic physiology of hair cells. PMID:22682011

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

    Science.gov (United States)

    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 (< 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. PMID:27448330

  2. 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...

  3. 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...

  4. Intracochlear misdirected implantation of a cochlear implant

    NARCIS (Netherlands)

    Tange, R A; Grolman, W; Maat, A

    2006-01-01

    This paper discusses a rare complication of an intracochlear misdirection of the electrode of a cochlear implant in a 55-year-old male. The patient received a cochlear implant using the mastoid-saving surgical approach. Intraoperative measurements showed impedance and NRT reactions suggesting a reas

  5. 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.

  6. The convergence of cochlear implantation with induced pluripotent stem cell therapy.

    Science.gov (United States)

    Gunewardene, Niliksha; Dottori, Mirella; Nayagam, Bryony A

    2012-09-01

    According to 2010 estimates from The National Institute on Deafness and other Communication Disorders, approximately 17% (36 million) American adults have reported some degree of hearing loss. Currently, the only clinical treatment available for those with severe-to-profound hearing loss is a cochlear implant, which is designed to electrically stimulate the auditory nerve in the absence of hair cells. Whilst the cochlear implant has been revolutionary in terms of providing hearing to the severe-to-profoundly deaf, there are variations in cochlear implant performance which may be related to the degree of degeneration of auditory neurons following hearing loss. Hence, numerous experimental studies have focused on enhancing the efficacy of cochlear implants by using neurotrophins to preserve the auditory neurons, and more recently, attempting to replace these dying cells with new neurons derived from stem cells. As a result, several groups are now investigating the potential for both embryonic and adult stem cells to replace the degenerating sensory elements in the deaf cochlea. Recent advances in our knowledge of stem cells and the development of induced pluripotency by Takahashi and Yamanaka in 2006, have opened a new realm of science focused on the use of induced pluripotent stem (iPS) cells for therapeutic purposes. This review will provide a broad overview of the potential benefits and challenges of using iPS cells in combination with a cochlear implant for the treatment of hearing loss, including differentiation of iPS cells into an auditory neural lineage and clinically relevant transplantation approaches. PMID:21956409

  7. 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.

  8. 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.

  9. 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.

  10. Premature graying of hair

    Directory of Open Access Journals (Sweden)

    Deepika Pandhi

    2013-01-01

    Full Text Available Premature graying is an important cause of low self-esteem, often interfering with socio-cultural adjustment. The onset and progression of graying or canities correlate very closely with chronological aging, and occur in varying degrees in all individuals eventually, regardless of gender or race. Premature canities may occur alone as an autosomal dominant condition or in association with various autoimmune or premature aging syndromes. It needs to be differentiated from various genetic hypomelanotic hair disorders. Reduction in melanogenically active melanocytes in the hair bulb of gray anagen hair follicles with resultant pigment loss is central to the pathogenesis of graying. Defective melanosomal transfers to cortical keratinocytes and melanin incontinence due to melanocyte degeneration are also believed to contribute to this. The white color of canities is an optical effect; the reflection of incident light masks the intrinsic pale yellow color of hair keratin. Full range of color from normal to white can be seen both along individual hair and from hair to hair, and admixture of pigmented and white hair is believed to give the appearance of gray. Graying of hair is usually progressive and permanent, but there are occasional reports of spontaneous repigmentation of gray hair. Studies evaluating the association of canities with osteopenia and cardiovascular disease have revealed mixed results. Despite the extensive molecular research being carried out to understand the pathogenesis of canities, there is paucity of effective evidence-based treatment options. Reports of repigmentation of previously white hair following certain inflammatory processes and use of drugs have suggested the possibility of cytokine-induced recruitment of outer sheath melanocytes to the hair bulb and rekindled the hope for finding an effective drug for treatment of premature canities. In the end, camouflage techniques using hair colorants are outlined.

  11. Taking Care of Your Hair

    Science.gov (United States)

    ... or pulling them out without professional help can cause hair and scalp damage or even hair loss. Sometimes hair breakage and dry, brittle hair are signs of a medical problem, such as hypothyroidism or an eating disorder. If your hair is breaking even though you ...

  12. Mercury in human hair

    International Nuclear Information System (INIS)

    The analysis of mercury (Hg) in scalp hair obtained from individuals residing in five different localities in the Philippines - Metro Manila, Naga City in Bicol, Bataan, Oriental Mindoro, and Palawan is presented. An overall mean of 1.46 ug/g of hair was obtained for all samples excluding those from Palawan and represents a baseline value.'' In terms of the mercury levels found in hair, the Honda Bay area in Palawan is, relatively, a ''contaminated area.'' (author)

  13. Hair Follicle Pigmentation

    OpenAIRE

    Slominski, Andrzej; Wortsman, Jacobo; Plonka, Przemyslaw M.; Schallreuter, Karin U.; Paus, Ralf; Tobin, Desmond J.

    2005-01-01

    Hair shaft melanin components (eu- or/and pheomelanin) are a long-lived record of precise interactions in the hair follicle pigmentary unit, e.g., between follicular melanocytes, keratinocytes, and dermal papilla fibroblasts. Follicular melanogenesis (FM) involves sequentially the melanogenic activity of follicular melanocytes, the transfer of melanin granules into cortical and medulla keratinocytes, and the formation of pigmented hair shafts. This activity is in turn regulated by an array of...

  14. Hair cell ribbon synapses

    OpenAIRE

    Moser, Tobias; Brandt, Andreas; Lysakowski, Anna

    2006-01-01

    Hearing and balance rely on the faithful synaptic coding of mechanical input by the auditory and vestibular hair cells of the inner ear. Mechanical deflection of their stereocilia causes the opening of mechanosensitive channels, resulting in hair cell depolarization, which controls the release of glutamate at ribbon-type synapses. Hair cells have a compact shape with strong polarity. Mechanoelectrical transduction and active membrane turnover associated with stereociliar renewal dominate the ...

  15. 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

  16. 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.

  17. 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. PMID:24017982

  18. 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. PMID:18330794

  19. Tarantula hair keratitis.

    Science.gov (United States)

    Mangat, Simran Singh; Newman, Bill

    2012-10-26

    We describe a 12-year-old boy in England with keratitis secondary to tarantula hairs embedded within the stroma of his cornea. Every attempt must be made to isolate these hairs at the first visit as they have a barbed nature and have a propensity to propagate through ocular tissues. A chronic keratitis requiring long-term steroid use may result if hairs persist in the cornea. Children who keep tarantulas as pets should be instructed on safe handling to prevent the tarantula from adopting defence mechanisms and shedding their hairs. PMID:23242405

  20. Hair Dyes and Cancer Risk

    Science.gov (United States)

    ... Overview Cancer Prevention Overview–for health professionals Research Hair Dyes and Cancer Risk On This Page Why is ... over age 40 use some type of hair dye ( 1 ). Modern hair dyes are classified as permanent (or oxidative), semipermanent, ...

  1. Hair cosmetics and camouflage technics

    OpenAIRE

    Zahide Eriş Eken; Banu Taşkın; Sibel Alper

    2014-01-01

    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, hai...

  2. Is All Human Hearing Cochlear?

    Directory of Open Access Journals (Sweden)

    Seyede Faranak Emami

    2013-01-01

    Full Text Available The objective of this cross-sectional study was to investigate the possibility that the saccule may contribute to human hearing. The forty participants included twenty healthy people and twenty other subjects selected from patients who presented with benign paroxysmal positional vertigo to Audiology Department of Hazrat Rasoul Akram hospital (Tehran, Iran. Assessments comprised of audiological evaluations, cervical vestibular evoked myogenic potentials (cVEMPs, recognition of spoken phonemes in white noise (Rsp in wn, and auditory brainstem response to 500 Hz tone burst (ABR500 HZ. Twenty affected ears with decreased vestibular excitability as detected by abnormal cVEMPs revealed decreased scores of Rsp in wn and abnormal findings of ABR500 HZ. Both unaffected and normal ears had normal results. Multiple comparisons of mean values of cVEMPs and ABR500 HZ between three groups were significant (P<0.05, ANOVA. The correlation between RSP in wn and p13 latencies was significant. The peak-to-peak amplitudes showed significant correlation to RSP in wn. The correlation between RSP in wn and the latencies of n23 was significant. In high-level of noisy competing situations, healthy human saccular sensation can mediate the detection of low frequencies and possibly help in cochlear hearing for frequency and intensity discrimination. So, all human hearing is not cochlear.

  3. Cortical Plasticity after Cochlear Implantation

    Science.gov (United States)

    Petersen, B.; Gjedde, A.; Wallentin, M.; Vuust, P.

    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 recently implanted adult implant recipients listened to running speech or speech-like noise in four sequential PET sessions at each milestone. CI listeners with postlingual hearing loss showed differential activation of left superior temporal gyrus during speech and speech-like stimuli, unlike CI listeners with prelingual hearing loss. Furthermore, Broca's area was activated as an effect of time, but only in CI listeners with postlingual hearing loss. The study demonstrates that adaptation to the cochlear implant is highly related to the history of hearing loss. Speech processing in patients whose hearing loss occurred after the acquisition of language involves brain areas associated with speech comprehension, which is not the case for patients whose hearing loss occurred before the acquisition of language. Finally, the findings confirm the key role of Broca's area in restoration of speech perception, but only in individuals in whom Broca's area has been active prior to the loss of hearing. PMID:24377050

  4. Healthy hair: what is it?

    Science.gov (United States)

    Sinclair, Rodney D

    2007-12-01

    Shiny hair with a smooth texture and clean-cut ends or tapered tips is generally perceived to be healthy. Hair texture and shine relate to hair surface properties, whereas the integrity of hair ends relates to the hair cortex. Hair can be straight, wavy or curly, blonde, black, brown, red, gray white, and its natural variations are important to our identity. Manipulation of the normal structure of the hair shaft is epidemic and dictated by culture, fashion, and above all, celebrity. Although cosmetic procedures are intrinsically safe, there is potential for damage to the hair. Loss of lustre, frizz, split ends, and other hair problems are particularly prevalent among people who repeatedly alter the natural style of their hair or among people with hair that is intrinsically weak. This may be due to individual or racial variation or less commonly an inherited structural abnormality in hair fiber formation. Hair health is also affected by common afflictions of the scalp as well as age-related phenomena such as graying and androgenetic alopecia. Hair products that improve the structural integrity of hair fibers and increase tensile strength are available, as are products that increase hair volume, reduce frizz, improve hair manageability, and stimulate new hair growth. PMID:18004288

  5. 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.

  6. Cochlear function after selective spiral ganglion cells degeneration induced by ouabain

    Institute of Scientific and Technical Information of China (English)

    WANG Lin-e; CAO Ke-li; YIN Shan-kai; WANG Zhen; CHEN Zheng-nong

    2006-01-01

    Background Ouabain, a cardiac glycoside that specifically binds to Na/K-ATPase and inhibits its activity, was applied to gerbils to develop a method for studying auditory neuropathy.Methods Ouabain was applied to the round window of the cochlea in each gerbil by using a piece of gelfoam with 3 μl or 24 μl (1 mmol/L) ouabain solution. The changes of the threshold of auditory brainstem response,cochlear function round window electrocochleography, as well as the morphological changes of the spiral ganglion cells of the cochlea were observed after application of ouabain for 24 hours or 96 hours.Results:In ouabain treated gerbils, auditory brainstem response and compound action potential thresholds showed either elevation or no response at all. However, the thresholds of cochlear microphonic and distortion product otoacoustic emissions were not affected. Degeneration and necrosis of some spiral ganglion cells in ears with applications of ouabain (24 hours, 3 μl, 1 mmol/L; 96 hours, 24 μl, 1 mmol/L ouabain). The number of spiral ganglion cells was decreased (24 hours, 3 μl, 1 mmol/L ouabain) or near to a total loss (96 hours, 24 μl, 1 mmol/L ouabain).Conclusions:These results indicate a high degree of independence between the spiral ganglion cells and the outer hair cell systems in the cochlear transduction mechanism. The method used in this study would provide a valuable tool for studying auditory neuropathy.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Help! It's Hair Loss!

    Science.gov (United States)

    ... Homework? Here's Help White House Lunch Recipes Help! It's Hair Loss! KidsHealth > For Kids > Help! It's Hair Loss! Print A A A Text Size ... part above the skin, is dead. (That's why it doesn't hurt to get a haircut!) This ...

  12. 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.

  13. 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.

  14. [Hair follicle regeneration].

    Science.gov (United States)

    Itami, Satoshi

    2008-05-01

    Hair growth cycle is coordinated with complex processes that are dependent on the interactions of follicular stem cells and dermal papilla cells (DPCs). For the past 10 years, the developmental mechanism of hair follicles has been extensively studied, and spatial and temporal expressions of many molecules are required for the hair morphogenesis. These molecules are also required for hair cycle progression. Androgen receptor, which is a ligand dependent transcription factor, plays an important role in human hair cycle. Frontal scalp DPCs from androgenetic alopecia (AGA) are the target cells of androgen action. Minoxidil and Finasteride were recently introduced for the treatment of AGA, and cell therapy using DPCs is a next strategy for the innovative treatment. PMID:18464507

  15. Music Therapy for Preschool Cochlear Implant Recipients

    OpenAIRE

    Gfeller, Kate; Driscoll, Virginia; Kenworthy, Maura; Van Voorst, Tanya

    2011-01-01

    This paper provides research and clinical information relevant to music therapy for preschool children who use cochlear implants (CI). It consolidates information from various disciplinary sources regarding (a) cochlear implantation of young prelingually-deaf children (~age 2-5), (b) patterns of auditory and speech-language development, and (c) research regarding music perception of children with CIs. This information serves as a foundation for the final portion of the article, which describe...

  16. 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.

  17. Informed Consent, Deaf Culture, and Cochlear Implants.

    Science.gov (United States)

    Pass, Lauren; Graber, Abraham D

    2015-01-01

    While cochlear implantation is now considered routine in many parts of the world, the debate over how to ethically implement this technology continues. One's stance on implantation often hinges on one's understanding of deafness. On one end of the spectrum are those who see cochlear implants as a much needed cure for an otherwise intractable disability. On the other end of the spectrum are those who view the Deaf as members of a thriving culture and see the cochlear implant as an attempt to eliminate this culture. Rather than take a stance in this debate, we will argue that the informed consent process for cochlear implantation must include access to Deaf perspectives. Deaf individuals know best what it is like to be a member of the Deaf community; the reasonable person would put significant weight on the testimony of Deaf individuals when considering whether to undergo cochlear implantation. The reasonable person standard determines what information careproviders must present as part of the informed consent process; thus, informed consent for cochlear implantation requires access to the testimony of Deaf individuals. PMID:26399672

  18. [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. PMID:11766315

  19. [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.

  20. The adrenocortical response of tufted puffin chicks to nutritional deficits.

    Science.gov (United States)

    Kitaysky, Alexander S; Romano, Marc D; Piatt, John F; Wingfield, John C; Kikuchi, Motoshi

    2005-05-01

    In several seabirds, nutritional state of a nest-bound chick is negatively correlated with the activity of its hypothalamus-pituitary-adrenal (HPA) axis. Increased corticosterone (cort) secretion has been shown to facilitate changes in behavior that allow hungry chicks to obtain more food from parents. However, if parents are not willing/able to buffer their young from temporary food shortages, increased cort secretion could be detrimental to undernourished chicks. In a system where parents are insensitive to chick demands, low benefits and high costs of activation of the HPA-axis in hungry chicks should lead to a disassociation of the nutritional state of the young and the activity of its HPA-axis. We tested this novel hypothesis for the tufted puffin (Fratercula cirrhata), a seabird with intermittent provisioning of a nest-bound semi-precocial chick. We examined the HPA-axis activity of captive chicks exposed to the following: (1) a short-term (24 h) food deprivation; and (2) an array of prolonged (3 weeks) restrictions in feeding regimens. We found that in response to a short-term food deprivation chicks decreased baseline levels of cort and thyroid hormones. In response to prolonged restrictions, food-limited chicks exhibited signs of nutritional deficit: they had lower body mass, endogenous lipid reserves, and thyroid hormone titers compared to chicks fed ad libitum. However, baseline and maximum acute stress-induced levels of cort were also lower in food-restricted chicks compared to those of chicks fed ad libitum. These results support a major prediction of the study hypothesis that puffin chicks suppress HPA-axis activity in response to short- and long-term nutritional deficits. This physiological adaptation may allow a chick to extend its development in the nest, while eluding detrimental effects of chronic cort elevation. PMID:15811363

  1. 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.

  2. 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.

  3. Noise-induced hearing loss (NIHL) as a target of oxidative stress-mediated damage: cochlear and cortical responses after an increase in antioxidant defense.

    Science.gov (United States)

    Fetoni, Anna Rita; De Bartolo, Paola; Eramo, Sara Letizia Maria; Rolesi, Rolando; Paciello, Fabiola; Bergamini, Christian; Fato, Romana; Paludetti, Gaetano; Petrosini, Laura; Troiani, Diana

    2013-02-27

    This study addresses the relationship between cochlear oxidative damage and auditory cortical injury in a rat model of repeated noise exposure. To test the effect of increased antioxidant defenses, a water-soluble coenzyme Q10 analog (Qter) was used. We analyzed auditory function, cochlear oxidative stress, morphological alterations in auditory cortices and cochlear structures, and levels of coenzymes Q9 and Q10 (CoQ9 and CoQ10, respectively) as indicators of endogenous antioxidant capability. We report three main results. First, hearing loss and damage in hair cells and spiral ganglion was determined by noise-induced oxidative stress. Second, the acoustic trauma altered dendritic morphology and decreased spine number of II-III and V-VI layer pyramidal neurons of auditory cortices. Third, the systemic administration of the water-soluble CoQ10 analog reduced oxidative-induced cochlear damage, hearing loss, and cortical dendritic injury. Furthermore, cochlear levels of CoQ9 and CoQ10 content increased. These findings indicate that antioxidant treatment restores auditory cortical neuronal morphology and hearing function by reducing the noise-induced redox imbalance in the cochlea and the deafferentation effects upstream the acoustic pathway. PMID:23447610

  4. Why Does Hair Turn Gray?

    Science.gov (United States)

    ... sun . The dark or light color of someone's hair depends on how much melanin each hair contains. As we get older, the pigment cells ... cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color — like ...

  5. 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 ...

  6. Cochlear Implants Keep Twin Sisters Learning, Discovering Together

    Science.gov (United States)

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

  7. 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

  8. 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.

  9. Auditory hair cell defects as potential cause for sensorineural deafness in Wolf-Hirschhorn syndrome

    Directory of Open Access Journals (Sweden)

    Mohi Ahmed

    2015-09-01

    Full Text Available WHSC1 is a histone methyltransferase (HMT that catalyses the addition of methyl groups to lysine 36 on histone 3. In humans, WHSC1 haploinsufficiency is associated with all known cases of Wolf-Hirschhorn syndrome (WHS. The cardinal feature of WHS is a craniofacial dysmorphism, which is accompanied by sensorineural hearing loss in 15% of individuals with WHS. Here, we show that WHSC1-deficient mice display craniofacial defects that overlap with WHS, including cochlea anomalies. Although auditory hair cells are specified normally, their stereocilia hair bundles required for sound perception fail to develop the appropriate morphology. Furthermore, the orientation and cellular organisation of cochlear hair cells and their innervation are defective. These findings identify, for the first time, the likely cause of sensorineural hearing loss in individuals with WHS.

  10. CHICK PEAS EFFICIENCY IN HENS FEEDING

    OpenAIRE

    Nikolaev S. I.; Karapetyan A. K.; Kornilova E. V.; Struk M. V.

    2015-01-01

    This article presents the results of the chick peas use instead of sunflower cake, in feeding young and adult livestock hens-layers of the cross "Hajseks brown". The researches were carried out in the JSC "Agrofirm Vostok" of the Nikolayevskiy district in the Volgograd region. The sunflower cake replacement with legumes - chickpeas as the part of the experimental animal fodder for young and adult livestock hens-layers had a positive influence on productivity, physiological state of the birds,...

  11. Tips for Healthy Hair

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases Cosmetic treatments Dry / sweaty skin Eczema / dermatitis Hair and scalp ...

  12. Female Pattern Hair Loss

    Science.gov (United States)

    ... desired professional counseling might be of help. Perms, dyes and other cosmetic options can be used to give a fuller appearance to hair. Contrary to common wisdom, shampooing doesn't increase ...

  13. Scurvy, corkscrew hair (image)

    Science.gov (United States)

    Scurvy is a nutritional disease caused by deficiency of vitamin C. Pinpoint bleeding around hair follicles, and " ... this picture, can occur as a result of scurvy. Bleeding along the gums is common. This disease ...

  14. Investigating Outer Hair Cell Motility with a Combination of External Alternating Electrical Field Stimulation and High-speed Image Analysis

    OpenAIRE

    Kitani, Rei; Kalinec, Federico

    2011-01-01

    OHCs are cylindrical sensorimotor cells located in the Organ of Corti, the auditory organ inside the mammalian inner ear. The name "hair cells" derives from their characteristic apical bundle of stereocilia, a critical element for detection and transduction of sound energy 1. OHCs are able to change shape —elongate, shorten and bend— in response to electrical, mechanical and chemical stimulation, a motor response considered crucial for cochlear amplification of acoustic signals 2.

  15. Female Pattern Hair Loss

    OpenAIRE

    Herskovitz, Ingrid; Tosti, Antonella

    2013-01-01

    Context: Female pattern hair loss (FPHL) also known as female androgenetic alopecia is a common condition afflicting millions of women that can be cosmetically disrupting. Prompt diagnosis and treatment are essential for obtaining optimal outcome. This review addresses the clinical presentation of female pattern hair loss, its differential diagnosis and treatment modalities. Evidence Acquisition: A) Diffuse thinning of the crown region with preservation of the frontal hairline (Ludwig’s type)...

  16. 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

  17. Retrolabyrinthine approach for cochlear nerve preservation in neurofibromatosis type 2 and simultaneous cochlear implantation

    Directory of Open Access Journals (Sweden)

    Bento, Ricardo Ferreira

    2014-01-01

    Full Text Available Introduction: Few cases of cochlear implantation (CI in neurofibromatosis type 2 (NF2 patients had been reported in the literature. The approaches described were translabyrinthine, retrosigmoid or middle cranial fossa. Objectives: To describe a case of a NF2- deafened-patient who underwent to vestibular schwannoma resection via RLA with cochlear nerve preservation and CI through the round window, at the same surgical time. Resumed Report: A 36-year-old woman with severe bilateral hearing loss due to NF2 was submitted to vestibular schwannoma resection and simultaneous CI. Functional assessment of cochlear nerve was performed by electrical promontory stimulation. Complete tumor removal was accomplishment via RLA with anatomic and functional cochlear and facial nerve preservation. Cochlear electrode array was partially inserted via round window. Sound field hearing threshold improvement was achieved. Mean tonal threshold was 46.2 dB HL. The patient could only detect environmental sounds and human voice but cannot discriminate vowels, words nor do sentences at 2 years of follow-up. Conclusion: Cochlear implantation is a feasible auditory restoration option in NF2 when cochlear anatomic and functional nerve preservation is achieved. The RLA is adequate for this purpose and features as an option for hearing preservation in NF2 patients.

  18. 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...

  19. Distribution and time course of hair cell regeneration in the pigeon utricle

    Science.gov (United States)

    Dye, B. J.; Frank, T. C.; Newlands, S. D.; Dickman, J. D.

    1999-01-01

    Vestibular and cochlear regeneration following ototoxic insult from aminoglycoside antibiotics has been well documented, particularly in birds. In the present study, intraotic application of a 2 mg streptomycin paste was used to achieve complete vestibular hair cell destruction in pigeons (Columba livia) while preserving regenerative ability. Scanning electron microscopy was used to quantify hair cell density longitudinally during regeneration in three different utricular macula locations, including the striola, central and peripheral regions. The utricular epithelium was void of stereocilia (indicating hair cell loss) at 4 days after intraotic treatment with streptomycin. At 2 weeks the stereocilia began to appear randomly and mostly in an immature form. However, when present most kinocilia were polarized toward the developing striola. Initially, regeneration occurred more rapidly in the central and peripheral regions of the utricle as compared to the striola. As regeneration proceeded from 2 to 12 weeks, hair cell density in the striola region equaled the density noted in the central and peripheral regions. At 24 weeks, hair cell density of the central and peripheral regions was equal to normal values, however the striola region had a slightly greater hair cell density than that observed for normal animals.

  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. Cortical Plasticity after Cochlear Implantation

    Directory of Open Access Journals (Sweden)

    B. Petersen

    2013-01-01

    tomography at three time points: within 14 days, three months, and six months after switch-on. Fifteen recently implanted adult implant recipients listened to running speech or speech-like noise in four sequential PET sessions at each milestone. CI listeners with postlingual hearing loss showed differential activation of left superior temporal gyrus during speech and speech-like stimuli, unlike CI listeners with prelingual hearing loss. Furthermore, Broca’s area was activated as an effect of time, but only in CI listeners with postlingual hearing loss. The study demonstrates that adaptation to the cochlear implant is highly related to the history of hearing loss. Speech processing in patients whose hearing loss occurred after the acquisition of language involves brain areas associated with speech comprehension, which is not the case for patients whose hearing loss occurred before the acquisition of language. Finally, the findings confirm the key role of Broca’s area in restoration of speech perception, but only in individuals in whom Broca’s area has been active prior to the loss of hearing.

  2. Understanding music with cochlear implants

    Science.gov (United States)

    Bruns, Lisa; Mürbe, Dirk; Hahne, Anja

    2016-01-01

    Direct stimulation of the auditory nerve via a Cochlear Implant (CI) enables profoundly hearing-impaired people to perceive sounds. Many CI users find language comprehension satisfactory, but music perception is generally considered difficult. However, music contains different dimensions which might be accessible in different ways. We aimed to highlight three main dimensions of music processing in CI users which rely on different processing mechanisms: (1) musical discrimination abilities, (2) access to meaning in music, and (3) subjective music appreciation. All three dimensions were investigated in two CI user groups (post- and prelingually deafened CI users, all implanted as adults) and a matched normal hearing control group. The meaning of music was studied by using event-related potentials (with the N400 component as marker) during a music-word priming task while music appreciation was gathered by a questionnaire. The results reveal a double dissociation between the three dimensions of music processing. Despite impaired discrimination abilities of both CI user groups compared to the control group, appreciation was reduced only in postlingual CI users. While musical meaning processing was restorable in postlingual CI users, as shown by a N400 effect, data of prelingual CI users lack the N400 effect and indicate previous dysfunctional concept building. PMID:27558546

  3. Understanding music with cochlear implants.

    Science.gov (United States)

    Bruns, Lisa; Mürbe, Dirk; Hahne, Anja

    2016-01-01

    Direct stimulation of the auditory nerve via a Cochlear Implant (CI) enables profoundly hearing-impaired people to perceive sounds. Many CI users find language comprehension satisfactory, but music perception is generally considered difficult. However, music contains different dimensions which might be accessible in different ways. We aimed to highlight three main dimensions of music processing in CI users which rely on different processing mechanisms: (1) musical discrimination abilities, (2) access to meaning in music, and (3) subjective music appreciation. All three dimensions were investigated in two CI user groups (post- and prelingually deafened CI users, all implanted as adults) and a matched normal hearing control group. The meaning of music was studied by using event-related potentials (with the N400 component as marker) during a music-word priming task while music appreciation was gathered by a questionnaire. The results reveal a double dissociation between the three dimensions of music processing. Despite impaired discrimination abilities of both CI user groups compared to the control group, appreciation was reduced only in postlingual CI users. While musical meaning processing was restorable in postlingual CI users, as shown by a N400 effect, data of prelingual CI users lack the N400 effect and indicate previous dysfunctional concept building. PMID:27558546

  4. 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.

  5. Managing Chemotherapy Side Effects: Hair Loss (Alopecia)

    Science.gov (United States)

    ... C ancer I nstitute Managing Chemotherapy Side Effects Hair Loss (Alopecia) “Losing my hair was hard at first. Then ... and anywhere on your body may fall out. Hair loss is called alopecia. When will my hair start ...

  6. Aging changes in hair and nails

    Science.gov (United States)

    ... Hair color is due to a pigment called melanin , which hair follicles produce. Follicles are structures in the skin that make and grow hair. With aging, the follicles make less melanin, and this causes gray hair. Graying often begins ...

  7. Cochlear Damages Caused by Vibration Exposure

    OpenAIRE

    Moussavi Najarkola, Seyyed Ali; Khavanin, Ali; Mirzaei, Ramazan; Salehnia, Mojdeh; MUHAMMADNEJAD, AHAD

    2013-01-01

    Background Many industrial devices have an excessive vibration which can affect human body systems. The effect of vibration on cochlear histology has been as a debatable problem in occupational health and medicine. Objectives Due to limitation present in human studies, the research was conducted to survey the influence of vibration on cochlear histology in an animal model. Materials and Methods Twelve albino rabbits were experimented as: Vibration group (n = 6; exposed to 1.0 m.s-2 r.m.s vert...

  8. 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.

  9. Dermatotoxicologic clinical solutions: hair dying in hair dye allergic patients?

    Science.gov (United States)

    Edwards, Ashley; Coman, Garrett; Blickenstaff, Nicholas; Maibach, Howard

    2015-03-01

    This article describes how to identify allergic contact dermatitis resulting from hair dye, and outlines interventions and prevention principles for those who wish to continue dyeing their hair despite being allergic. Hair dye chemicals thought to be the most frequent sensitizers are discussed with instructions for health care providers on how to counsel patients about techniques to minimize exposure to allergenic substances. This framework should allow many patients to continue dyeing their hair without experiencing adverse side effects. PMID:24754409

  10. Hair analysis using PIXE

    International Nuclear Information System (INIS)

    A simple new technique for examining single hair strands to obtain linear mass densities, longitudinal profiles and transverse distribution of each trace element is described. It is primarily based upon the PIXE technique, in combination with proton back- scattering. The three main components of this technique are: 1) An accurate way of using an interpolation method to evaluate the magnitude of the correction factor accounting for the proton energy loss and X-ray absorption in the bulk of the hair is formulated; 2) A simple method to qualitatively determine the transverse distribution of each trace element in a hair is in- troduced and proved to be effective; 3) Proton back-scattering is proved to be capable of providing an ideal linear measure of the geometric hair diameter, one of the most important parameters in quantifying the results of PIXE measurements in mass concentrations. Using the technique, a PIXE system designed and constructed for routine longitudinal scanning of single hair strands is also described. (Author)

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

    OpenAIRE

    Poswal Arvind

    2007-01-01

    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 ...

  12. 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.

  13. 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.

  14. Inhibit Effects of N-acetylcysteine on Oxygen Free Radicals (OFR)-Induced Apoptosis in Cochlear Hair Cell%N-乙酰半胱氨酸对活性氧诱导耳蜗毛细胞凋亡的抑制作用的观察

    Institute of Scientific and Technical Information of China (English)

    原红艳; 张淑香; 李兴启; 李树华

    2012-01-01

    目的 探讨N-乙酰半胱氨酸(N-acetylcysteine,NAC)对活性氧诱导耳蜗毛细胞凋亡的抑制作用.方法 选用新生1~5天SD大鼠24只,随机分为4组,每组6只12耳:①无血清培养基组;②0.1 mmol/L H2O2组(H2O2组);③10 mmol/L N-乙酰半胱氨酸组(NAC组);④10 mmol/L NAC+0.1 mmol/L H2O2组(NAC+H2O2组).分离各组动物Corti器,分别放入相应培养液中培养,培养结束后用丫啶橙(YO)/碘化丙啶(PI)双重染色技术检测并计数凋亡毛细胞.结果 NAC组耳蜗基底膜的形态结构与无血清培养基组无明显差异,未见凋亡细胞;H2O2组可见大量凋亡细胞,细胞形态发生改变,出现水肿及碎裂,还有部分细胞缺失;NAC+ H2O2组细胞仍保持完好形态,只见少许凋亡细胞.结论 抗氧化剂NAC对外源性H2O2诱导的耳蜗毛细胞凋亡有抑制作用.%Objective To observe the inhibit effects of N-acctylcystcinc (NAC) on oxygen free radicals (OFR)-induced apoptosis in cochlcar hair cell. Methods We selected 24 neonatal SD rats of 1~5 days and divided them into 4 groups,6 rats(12 cars) in each group: ① Scrum-Free Mcdium;②0. 1 mmol/L H2O2;③10 mmol/L NAC;④10 mmol/L NAC+0. 1 mmol/L H2O2. Forty-eight hours after the tissues cultivation, the tissues were stained by AO and PI. The ratio of apoptotic cells in different groups were observed. Results The morphological structure of cochlcar basilar membrane had no difference between group NAC and group scrum-free medium. Lots of apoptotic cells were detected in the group H2O2 , the morphological structure changed, edematous and fragmentation, and loss of cells were observed. Group NAC+H2O2 remained intact morphology,little apoptotic cell were detected. Conclusion Under the conditions of our experiment, NAC can inhibit the OFR- induced apoptosis in cochlea hair cells.

  15. 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...

  16. 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...

  17. Effects of Vitamin C and Hydrogen Dioxide on the Electric Current of Large-conductance Calcium-activated Potassium Channels in Isolated Outer Hair Cells of Old Guinea Pigs’ Cochlears%维生素C与过氧化氢对老年豚鼠耳蜗外毛细胞大电导钙激活钾通道电流的影响

    Institute of Scientific and Technical Information of China (English)

    赖丹; 黄非; 覃纲

    2015-01-01

    outer hair cells in aging guinea pigs .Methods Acute enzyme was used to isolat outer hair cells of aging guinea pigs ,in which of BKCa channel's electric current was observed and recorded by whole-cell recording mode of patch -clamp .After recording the stable and normal electric current of BKCa channels ,added H2 O2 dilution (0 .2 mmol/L) 40 μl in the 2 ml chambers within freshly isolated outer hair cells so that the concen‐tration of H2 O2 in the balneum would be 4 μmol /L .The groups(n=5) received individually vitamin C solution (5 mg/ml) 0 ,10 ,20 ,40μl in the 2 ml chambers within freshly isolated outer hair cells so that the concentration of vi‐tamin C in the balneum would be 0 ,25 ,50 ,100 μg /ml ,observing and recording the effects of different concentration of vitamin C to electric current of BKCa channels .Results ①In the w hole-cell mode of patch -clamp ,the rapid activation and non-deactivation electric current with a string of large amplitude was recorded ,above -40~ -30 mV activation voltage .The electric current increased with the increasing membrane potential .The amplitude in‐creased continuously and performed characteristics of outward rectification .When the concentration of IbTX was 100 nmol /L ,the activity of the channel was completely blocked and confirmed BKCa channel's electric current .②Medication within three minutes ,when VT was +50 mV ,the BKCa channels'the maximum peak current densities of 4 μmol /L H2 O2 group rose from 22 .09 ± 0 .27 PA /PF to 43 .53 ± 1 .09 PA/PF ,amplification was 97 .06% .In H2 O2 4 μmol /L + vitamin C with different concentrations as 25 ,50 ,100 μg/ml groups ,the BKCa channels'elec‐tric current performed about concentration-dependent inhibition ,and electric current's amplitude and peak current density decreased with the increasing concentration of vitamin C ,the I-V curves were reduced .However ,this still could not be recovered to the normal levels .Conclusion The oxygen free radical /BKCa exists

  18. 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

  19. 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

  20. Gamma irradiation treatment of cereal grains for chick diets

    International Nuclear Information System (INIS)

    Wheat (W), triticale (T), hulled barley (HB), hull-less barley (HLB), hulled oats (HO), and hull-less oats (HLO) were gamma irradiated (60Co) at 0, 3, 6 and 9 Mrad to study the effect of irradiation on the nutritional value of cereal grains for chicks. A significant curvilinear relationship between radiation dose and 3-wk body weight of chicks fed irradiated cereals was noted for T, HB, HLB, HO and HLO. Chicks fed W or T showed no effect or lower body weight, respectively, while body weights of chicks fed barley or oat samples were higher with irradiation. The improvement tended to be maximal at the 6 Mrad level. Irradiation significantly improved the gain-to-feed ratio for chicks fed either HO or HLO. Apparent fat retention and tibia ash were higher in chicks fed irradiated HLO than in those fed untreated HLO. In a second experiment chick body weight, apparent amino acid and fat retention, tibia ash, and gain-to-feed ratios were lower in chicks fed autoclaved (121 degrees C for 20 min) barley than in those fed untreated barley. Irradiation (6 Mrad) subsequent to autoclaving barley samples eliminated these effects. Irradiation appears to benefit cereals containing soluble or mucilagenous fiber types as typified by beta-glucan of barley and oats. These fibers appear prone to irradiation-induced depolymerization, as suggested by increased beta-glucan solubility and reduced extract viscosity for irradiated barley and oat samples

  1. Use of Vaccines to Prevent Meningitis in Persons with Cochlear Implants

    Science.gov (United States)

    ... conjugate vaccine=MenACWY Use of Vaccines to Prevent Meningitis in Persons with Cochlear Implants Recommend on Facebook ... cochlear implants are more likely to get bacterial meningitis than children without cochlear implants. In addition, some ...

  2. Exploring the Role of Mechanotransduction Activation and Adaptation Kinetics in Hair Cell Filtering Using a Hodgkin-Huxley Approach

    Science.gov (United States)

    Wells, Gregg B.; Ricci, Anthony J.

    2011-11-01

    In the auditory system, mechanotransduction occurs in the hair cell sensory hair bundle and is the first major step in the translation of mechanical energy into electrical. Tonotopic variations in the activation kinetics of this process are posited to provide a low pass filter to the input. An adaptation process, also associated with mechanotransduction, is postulated to provide a high pass filter to the input in a tonotopic manner. Together a bandpass filter is created at the hair cell input. Corresponding mechanical components to both activation and adaptation are also suggested to be involved in generating cochlear amplification. A paradox to this story is that hair cells where the mechanotransduction properties are most robust possess an intrinsic electrical resonance mechanism proposed to account for all required tuning and amplification. A simple Hodgkin-Huxley type model is presented to attempt to determine the role of the activation and adaptation kinetics in further tuning hair cells that exhibit electrical resonance. Results further support that steady state mechanotransduction properties are critical for setting the resting potential of the hair cell while the kinetics of activation and adaptation are important for sharpening tuning around the characteristic frequency of the hair cell.

  3. Listening Effort with Cochlear Implant Simulations

    Science.gov (United States)

    Pals, Carina; Sarampalis, Anastasios; Baskent, Deniz

    2013-01-01

    Purpose: Fitting a cochlear implant (CI) for optimal speech perception does not necessarily optimize listening effort. This study aimed to show that listening effort may change between CI processing conditions for which speech intelligibility remains constant. Method: Nineteen normal-hearing participants listened to CI simulations with varying…

  4. Accurate Guitar Tuning by Cochlear Implant Musicians

    OpenAIRE

    Thomas Lu; Juan Huang; Fan-Gang Zeng

    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

  5. The management of cochlear nerve deficiency.

    Science.gov (United States)

    Freeman, S R; Stivaros, S M; Ramsden, R T; O'Driscoll, M P; Nichani, J R; Bruce, I A; Green, K M; Henderson, L A; Rutherford, S A; King, A T; Lloyd, S K

    2013-11-01

    The assessment process is critical in deciding whether a profoundly deaf child with cochlear nerve deficiency (CND) will be suitable for a cochlear or auditory brainstem implant (ABI). Magnetic resonance imaging (MRI) using submillimetric T2 weighted gradient echo or turbo spin echo sequences is mandatory for all profoundly deaf children to diagnose CND. Evidence of audition on behavioural or electrophysiological tests following both auditory and electrical stimulation sometimes allows identification of significant auditory tissue not visible on MRI. In particular electric auditory brainstem response (EABR) testing may allow some quantification of auditory tissue and help decide whether a cochlear implant will be beneficial. Age and cognitive development are the most critical factors in determining ABI benefit. Hearing outcomes from both cochlear implants and ABIs are variable and likely to be limited in children with CND. A proportion of children will get no benefit. Usually the implants would be expected to provide recognition of environmental sounds and understanding of simple phonetics. Most children will not develop normal speech and they will often need to learn to communicate with sign language. The ABI involves a major neurosurgical procedure and at present the long term outcomes are unknown. It is therefore essential that parents who are considering this intervention have plenty of time to consider all aspects and the opportunity for in depth discussion. PMID:24533760

  6. Simplifying cochlear implant speech processor fitting

    NARCIS (Netherlands)

    Willeboer, C.

    2008-01-01

    Conventional fittings of the speech processor of a cochlear implant (CI) rely to a large extent on the implant recipient's subjective responses. For each of the 22 intracochlear electrodes the recipient has to indicate the threshold level (T-level) and comfortable loudness level (C-level) while stim

  7. Impairment of Caloric Function after Cochlear Implantation

    Science.gov (United States)

    Kuang, Heide; Haversat, Heather H.; Michaelides, Elias M.

    2015-01-01

    Purpose: This article seeks to review current literature on caloric function following cochlear implantation while analyzing any correlations of caloric function changes with vestibular symptoms. Method: This article is a systematic review of evidence-based literature. English language articles published between 1980 and 2014 that presented some…

  8. 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.

  9. 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...

  10. Toxicity of Kalanchoe spp to chicks.

    Science.gov (United States)

    Williams, M C; Smith, M C

    1984-03-01

    Leaves of Kalanchoe daigremontiana, K tubiflora, K fedtschenkoi, K tomentosa, K tomentosa X K beharensis, and 4 cultivars of K blossfeldiana were tested for toxicity to 2-week-old Leghorn chicks. These species were analyzed for percentage of alkaloids, aliphatic nitro compounds, soluble oxalates, and nitrates and were examined qualitatively for cyanogenic glycosides. The solubility of the toxic principle in K daigremontiana was determined. Leaves of K daigremontiana, K tubiflora, and K fedtschenkoi were toxic to chicks at dosage levels of 8 to 12 mg/g of body weight. Toxic signs included depression, muscular incoordination, twitching and spiraling of the neck, tremors, convulsions, paralysis, and death. Kalanchoe tomentosa, K tomentosa X K beharensis, and 4 cultivars of K blossfeldiana were nontoxic at the highest dosage levels tested. Aliphatic nitro compounds and cyanogenic glycosides were not detected in any species. Alkaloids, nitrates, and soluble oxalates were present only in nontoxic concentrations. The toxic principle in K daigremontiana was soluble in 50%, 80%, and 100% ethanol, slightly soluble in water and acetone, and insoluble in benzene, chloroform, and ether. PMID:6711983

  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. Hair shafts in trichoscopy: clues for diagnosis of hair and scalp diseases.

    Science.gov (United States)

    Rudnicka, Lidia; Rakowska, Adriana; Kerzeja, Marta; Olszewska, Małgorzata

    2013-10-01

    Trichoscopy (hair and scalp dermoscopy) analyzes the structure and size of growing hair shafts, providing diagnostic clues for inherited and acquired causes of hair loss. Types of hair shaft abnormalities observed include exclamation mark hairs (alopecia areata, trichotillomania, chemotherapy-induced alopecia), Pohl-Pinkus constrictions (alopecia areata, chemotherapy-induced alopecia, blood loss, malnutrition), comma hairs (tinea capitis), corkscrew hairs (tinea capitis), coiled hairs (trichotillomania), flame hairs (trichotillomania), and tulip hairs (in trichotillomania, alopecia areata). Trichoscopy allows differential diagnosis of most genetic hair shaft disorders. This article proposes a classification of hair shaft abnormalities observed by trichoscopy. PMID:24075554

  13. Hearing loss and hair cell death in mice given the cholesterol-chelating agent hydroxypropyl-β-cyclodextrin.

    Directory of Open Access Journals (Sweden)

    Mark A Crumling

    Full Text Available Cyclodextrins are sugar compounds that are increasingly finding medicinal uses due to their ability to complex with hydrophobic molecules. One cyclodextrin in particular, 2-hydroxypropyl-β-cyclodextrin (HPβCD, is used as a carrier to solubilize lipophilic drugs and is itself being considered as a therapeutic agent for treatment of Niemann-Pick Type C disease, due to its ability to mobilize cholesterol. Results from toxicological studies suggest that HPβCD is generally safe, but a recent study has found that it causes hearing loss in cats. Whether the hearing loss occurred via death of cochlear hair cells, rendering it permanent, was unexplored. In the present study, we examined peripheral auditory function and cochlear histology in mice after subcutaneous injection of HPβCD to test for hearing loss and correlate any observed auditory deficits with histological findings. On average, auditory brainstem response thresholds were elevated at 4, 16, and 32 kHz in mice one week after treatment with 8,000 mg/kg. In severely affected mice all outer hair cells were missing in the basal half of the cochlea. In many cases, surviving hair cells in the cochlear apex exhibited abnormal punctate distribution of the motor protein prestin, suggesting long term changes to membrane composition and integrity. Mice given a lower dose of 4,000 mg/kg exhibited hearing loss only after repeated doses, but these threshold shifts were temporary. Therefore, cyclodextrin-induced hearing loss was complex, involving cell death and other more subtle influences on cochlear physiology.

  14. 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.

  15. Telogen Effluvium Hair Loss

    Science.gov (United States)

    ... for Authors Information for Reviewers Human & Animal Rights Job Postings Sections of the JAOCD JAOCD Archive Published Members Online Dermatology Journals Edit This Favorite Name: Category: Share: Yes No, Keep Private Telogen Effluvium Hair Loss Share | It is normal to lose up to ...

  16. Anacreon's pubic hair

    OpenAIRE

    Giangrande, Giusseppe

    1995-01-01

    Un análisis de Anacr. 13 Gent. demuestra que allen tina del verso 8 se refiere al vello púbico del poeta. An analysis of Anacr. 13 Gent. demonstrates that ᾶλλην τινά in line 8 denotes the poets's pubic hair.

  17. Hair Pulling (Trichotillomania)

    Science.gov (United States)

    ... children and adolescents may be teased, have low self esteem, anxiety or depression. Parents can become frustrated, as it is very difficult ... can’t simply stop pulling their hair. Neither parents nor children are to ... with self-esteem. In order to avoid punishment or embarrassment, children ...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Black Hole's 1/N Hair

    CERN Document Server

    Dvali, Gia

    2013-01-01

    According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers.

  3. Female pattern hair loss

    Directory of Open Access Journals (Sweden)

    Archana Singal

    2013-01-01

    Full Text Available Female pattern hair loss (FPHL is a common cause of hair loss in women characterized by diffuse reduction in hair density over the crown and frontal scalp with retention of the frontal hairline. Its prevalence increases with advancing age and is associated with significant psychological morbidity. The pathophysiology of FPHL is still not completely understood and seems to be multifactorial. Although androgens have been implicated, the involvement of androgen-independent mechanisms is evident from frequent lack of clinical or biochemical markers of hyperandrogenism in affected women. The role of genetic polymorphisms involving the androgen and estrogen receptors is being increasingly recognized in its causation and predicting treatment response to anti-androgens. There are different clinical patterns and classifications of FPHL, knowledge of which facilitates patient management and research. Chronic telogen effluvium remains as the most important differential diagnosis. Thorough history, clinical examination, and evaluation are essential to confirm diagnosis. Patients with clinical signs of androgen excess require assessment of biochemical parameters and imaging studies. It is prudent to screen the patients for metabolic syndrome and cardiovascular risk factors. The treatment comprises medical and/or surgical modalities. Medical treatment should be initiated early as it effectively arrests hair loss progression rather than stimulating regrowth. Minoxidil continues to be the first line therapy whereas anti-androgens form the second line of treatment. The progressive nature of FPHL mandates long-term treatment for sustained effect. Medical therapy may be supplemented with cosmetic concealment in those desirous of greater hair density. Surgery may be worthwhile in some carefully selected patients.

  4. Factors contributing to communication skills development in cochlear implanted children

    OpenAIRE

    Ostojić Sanja; Đoković Sanja; Radić-Šestić Marina; Nikolić Mina; Mikić Branka; Mirić Danica

    2015-01-01

    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 focuse...

  5. Prelingual deafness: Benefits from cochlear implants versus conventional hearing aids

    OpenAIRE

    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 c...

  6. Investigations of prosody perception by adult cochlear implant recipients

    DEFF Research Database (Denmark)

    Morris, David Jackson

    -synthesized speech to investigate the perceptual abilities of adult cochlear implant listeners in Danish and Swedish language settings. These studies examine performance relationships between prosody and other indexes of speech perception, including common clinical measurements.Results shed light on inherent device...... limitations and speech perception via an electrical-neural interface. This thesis is relevant to auditory rehabilitation, cochlear implant candidacy issues and sound processing in cochlear implants....

  7. Single and Multiple Microphone Noise Reduction Strategies in Cochlear Implants

    OpenAIRE

    Kokkinakis, Kostas; Azimi, Behnam; Hu, Yi; Friedland, David R.

    2012-01-01

    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 noi...

  8. The zinc finger transcription factor Gfi1, implicated in lymphomagenesis, is required for inner ear hair cell differentiation and survival

    Science.gov (United States)

    Wallis, Deeann; Hamblen, Melanie; Zhou, Yi; Venken, Koen J T.; Schumacher, Armin; Grimes, H. Leighton; Zoghbi, Huda Y.; Orkin, Stuart H.; Bellen, Hugo J.

    2003-01-01

    Gfi1 was first identified as causing interleukin 2-independent growth in T cells and lymphomagenesis in mice. Much work has shown that Gfi1 and Gfi1b, a second mouse homolog, play pivotal roles in blood cell lineage differentiation. However, neither Gfi1 nor Gfi1b has been implicated in nervous system development, even though their invertebrate homologues, senseless in Drosophila and pag-3 in C. elegans are expressed and required in the nervous system. We show that Gfi1 mRNA is expressed in many areas that give rise to neuronal cells during embryonic development in mouse, and that Gfi1 protein has a more restricted expression pattern. By E12.5 Gfi1 mRNA is expressed in both the CNS and PNS as well as in many sensory epithelia including the developing inner ear epithelia. At later developmental stages, Gfi1 expression in the ear is refined to the hair cells and neurons throughout the inner ear. Gfi1 protein is expressed in a more restricted pattern in specialized sensory cells of the PNS, including the eye, presumptive Merkel cells, the lung and hair cells of the inner ear. Gfi1 mutant mice display behavioral defects that are consistent with inner ear anomalies, as they are ataxic, circle, display head tilting behavior and do not respond to noise. They have a unique inner ear phenotype in that the vestibular and cochlear hair cells are differentially affected. Although Gfi1-deficient mice initially specify inner ear hair cells, these hair cells are disorganized in both the vestibule and cochlea. The outer hair cells of the cochlea are improperly innervated and express neuronal markers that are not normally expressed in these cells. Furthermore, Gfi1 mutant mice lose all cochlear hair cells just prior to and soon after birth through apoptosis. Finally, by five months of age there is also a dramatic reduction in the number of cochlear neurons. Hence, Gfi1 is expressed in the developing nervous system, is required for inner ear hair cell differentiation, and its loss

  9. 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

  10. Stronger efferent suppression of cochlear neural potentials by contralateral acoustic stimulation in awake than in anesthetized chinchilla

    Directory of Open Access Journals (Sweden)

    Cristian eAedo

    2015-03-01

    Full Text Available There are two types of sensory cells in the mammalian cochlea, inner hair cells, which make synaptic contact with auditory-nerve afferent fibers, and outer hair cells that are innervated by crossed and uncrossed medial olivocochlear (MOC efferent fibers. Contralateral acoustic stimulation activates the uncrossed efferent MOC fibers reducing cochlear neural responses, thus modifying the input to the central auditory system. The chinchilla, among all studied mammals, displays the lowest percentage of uncrossed MOC fibers raising questions about the strength and frequency distribution of the contralateral-sound effect in this species. On the other hand, MOC effects on cochlear sensitivity have been mainly studied in anesthetized animals and since the MOC-neuron activity depends on the level of anesthesia, it is important to assess the influence of anesthesia in the strength of efferent effects. Seven adult chinchillas (Chinchilla laniger were chronically implanted with round-window electrodes in both cochleae. We compared the effect of contralateral sound in awake and anesthetized condition. Compound action potentials (CAP and cochlear microphonics (CM were measured in the ipsilateral cochlea in response to tones in absence and presence of contralateral sound. Control measurements performed after middle-ear muscles section in one animal discarded any possible middle-ear reflex activation. Contralateral sound produced CAP amplitude reductions in all chinchillas, with suppression effects greater by about 1-3 dB in awake than in anesthetized animals. In contrast, CM amplitude increases of up to 1.9 dB were found in only three awake chinchillas. In both conditions the strongest efferent effects were produced by contralateral tones at frequencies equal or close to those of ipsilateral tones. Contralateral CAP suppressions for 1-6 kHz ipsilateral tones corresponded to a span of uncrossed MOC fiber innervation reaching at least the central third of the

  11. Object Individuation in 3-Day-Old Chicks: Use of Property and Spatiotemporal Information

    Science.gov (United States)

    Fontanari, Laura; Rugani, Rosa; Regolin, Lucia; Vallortigara, Giorgio

    2011-01-01

    Object individuation was investigated in newborn domestic chicks. Chicks' spontaneous tendency to approach the larger group of familiar objects was exploited in a series of five experiments. In the first experiment newborn chicks were reared for 3 days with objects differing in either colour, shape or size. At test, each chick was presented with…

  12. Mass stranding of wedge-tailed shearwater chicks in Hawaii.

    Science.gov (United States)

    Work, T M; Rameyer, R A

    1999-07-01

    Unusual numbers of wedge-tailed shearwater (Puffinus pacificus) chicks stranded on Oahu (Hawaii, USA) in 1994. Compared to healthy wedge-tailed shearwater (WTSW) chicks, stranded chicks were underweight, dehydrated, leukopenic, lymphopenic, eosinopenic, and heterophilic; some birds were toxemic and septic. Stranded chicks also were hypoglycemic and had elevated aspartate amino transferase levels. Most chicks apparently died from emaciation, dehydration, or bacteremia. Because many birds with bacteremia also had severe necrosis of the gastrointestinal (GI) mucosa associated with bacteria, we suspect the GI tract to be the source of disseminated bacterial infection. The identity of the bacteria was not confirmed. The daily number of chicks stranded was significantly related to average wind speeds, and the mortality coincided with the fledging period for WTSW. Strong southeasterly winds were a distinguishing meteorologic factor in 1994 and contributed to the distribution of stranded chicks on Oahu. More objective data on WTSW demographics would enhance future efforts to determine predisposing causes of WTSW wrecks and their effects on seabird colonies. PMID:10479083

  13. Mass stranding of wedge-tailed shearwater chicks in Hawaii

    Science.gov (United States)

    Work, T.M.; Rameyer, R.A.

    1999-01-01

    Unusual numbers of wedge-tailed shearwater (Puffinus pacificus) chicks stranded on Oahu (Hawaii, USA) in 1994. Compared to healthy wedge-tailed shearwater (WTSW) chicks, stranded chicks were underweight, dehydrated, leukopenic, lymphopenic, eosinopenic, and heterophilic; some birds were toxemic and septic. Stranded chicks also were hypoglycemic and had elevated aspartate amino transferase levels. Most chicks apparently died from emaciation, dehydration, or bacteremia. Because many birds with bacteremia also had severe necrosis of the gastrointestinal (GI) mucosa associated with bacteria, we suspect the GI tract to be the source of disseminated bacterial infection. The identity of the bacteria was not confirmed. The daily number of chicks stranded was significantly related to average wind speeds, and the mortality coincided with the fledging period for WTSW. Strong southeasterly winds were a distinguishing meteorologic factor in 1994 and contributed to the distribution of stranded chicks on Oahu. More objective data on WTSW demographics would enhance future efforts to determine predisposing causes of WTSW wrecks and their effects on seabird colonies.

  14. Cochlear implantation and change in quality of life

    DEFF Research Database (Denmark)

    Faber, Christian; Grøntved, Ågot Møller

    2000-01-01

    The aim of this study was to assess the benefits of cochlear implantation (CI) in adults and to evaluate the average implant usage per day. Ten profoundly deaf adults were implanted during the period April 1994 to September 1997. The patients answered questionnaires 1 year or more after receiving...... their cochlear implants. All of the patients used their implant daily. The average implant usage per day was 16 h. The patients stated that, given the choice, they would again opt for a cochlear implant and would recommend a cochlear implant for a deaf friend. A paired comparison showed that the implants led...

  15. 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.

  16. Performance of Broiler Chicks Fed Irradiated Sorghum Grains

    International Nuclear Information System (INIS)

    Substitution of yellow corn with raw sorghum grains in chick diets resulted in decreases in live body weight, accumulative feed consumption and efficiency of feed utilization as compared with reference diet. Relative to raw sorghum diet, inclusion of sorghum grains irradiated at 60 and 100 kGy and/or supplemented with PEG in chick diets resulted in increases in accumulative feed consumption an efficiency feed utilization. The study suggested that irradiation treatment up to 100 kGy up grade broiler chicks performance and the combinations between radiation and PEG treatments sustain the effect of each other

  17. Slimy hairs: Hair sensors made with slime mould

    OpenAIRE

    Adamatzky, Andrew

    2013-01-01

    Slime mould Physarum polycephalum is a large single cell visible by unaided eye. We design a slime mould implementation of a tactile hair, where the slime mould responds to repeated deflection of hair by an immediate high-amplitude spike and a prolonged increase in amplitude and width of its oscillation impulses. We demonstrate that signal-to-noise ratio of the Physarum tactile hair sensor averages near six for the immediate response and two for the prolonged response.

  18. 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.

  19. Interaction of human and chick DNA repair functions in UV-irradiated xeroderma pigmentosum-chick erythrocyte heterokaryons

    International Nuclear Information System (INIS)

    Fusion of chick erythrocytes with human primary fibroblasts results in the formation of heterokaryons in which the inactive chick nuclei become reactivated. The expression of chick DNA repair functions was investigated by the analysis of the DNA repair capacity after exposure to ultraviolet (UV) irradiation of such heterokaryons obtained after fusion of chick erythrocytes with normal human or xeroderma pigmentosum (XP) cells of complementation groups A, B, C and D. Unscheduled DNA synthesis (UDS) in normal human nuclei in these heterokaryons is suppressed during the first 2-4 days after fusion. The extent and duration of this suppression is positively correlated with the number of chick nuclei in the heterokaryons. Suppression is absent in heterokaryons obtained after fusion of chicken embryonic fibroblasts with XP cells (complementation group A and C). Restoration of DNA repair synthesis is found after fusion in XP nuclei of all complementation groups studied. It occurs rapidly in XP group A nuclei, starting one day after fusion and reaching near normal human levels after 5-8 days. In nuceli of the B, C and D group increased levels of UDS are found 5 days after fusion. At 8 days after fusion the UDS level is about 50% of that found in normal human nuclei. The pattern of UDS observed in the chick nuclei parallels that of the human counterpart in the fusion. In heterokaryons obtained after fusion of chick fibroblasts with XP group C cells UDS remains at the level of chick cells. These suggest that reactivation of chick erythrocyte nuclei results in expression of repair functions which are able to complement the defects in the XP complementation groups A, B, C and D

  20. Direct testing of the biasing effect of manipulations of endolymphatic pressure on cochlear mechanical function

    Science.gov (United States)

    LePage, Eric; Avan, Paul

    2015-12-01

    The history of cochlear mechanical investigations has been carried out in two largely separate sets of endeavours; those interested in auditory processing in animal models and those interested in the origin of adverse vestibular symptoms in humans. In respect of the first, mechanical vibratory data is considered pathological and not representative of pristine behaviour if it departs from the reigning model of sharp tuning and high hearing sensitivity. Conversely, when the description of the pathological behaviour is the focus, fluid movements responsible for hearing loss and vestibular symptoms dominate. Yet both extensive sets of data possess a common factor now being reconsidered for its potential to shed light on the mechanisms in general. The common factor is a mechanical bias — the departure of cochlear epithelial membranes from their usual resting position. In both cases the bias modulates hearing sensitivity and distorts tuning characteristics. Indeed several early sets of guinea pig mechanical data were dismissed as "pathological" when in hindsight, the primary effect influencing the data was not loss of outer hair cell function per se, but a mechanical bias unknowingly introduced in process of making the measurement. Such biases in the displacement of the basilar membrane from its position are common, and may be caused by low-frequency sounds (topically including infrasound) or by variations in fluid volume in the chambers particularly applying the case of endolymphatic hydrops. Most biases are quantified in terms of visualisation of fluid volume change, electric potential changes and otoacoustic emissions. Notably many previous studies have also searched for raised pressures with negative results. Yet these repeated findings are contrary to the widespread notion that, at least when homeostasis is lost, it is a rise in endolymphatic pressure which is responsible for membrane rupture and Meniere's attacks. This current investigation in Mongolian gerbils

  1. 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. PMID:26370639

  2. 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

  3. 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.

  4. Membrane tether formation from voltage-clamped outer hair cells using optical tweezers

    Science.gov (United States)

    Qian, Feng; Ermilov, Sergey A.; Murdock, David R.; Brownell, William E.; Anvari, Bahman

    2004-06-01

    Outer hair cells contribute an active mechanical feedback to the vibrations of the cochlear structures resulting in the high sensitivity and frequency selectivity of normal hearing. We have designed and implemented a novel experimental setup that combines optical tweezers with patch-clamp apparatus to investigate the electromechanical properties of cellular plasma membranes. A micron-size bead trapped by the optical tweezers is brought in contact with the membrane of a voltage-clamped cell, and subsequently moved away to form a plasma membrane tether. Bead displacement during tether elongation is monitored by a quadrant photodetector to obtain time-resolved measurements of the tethering force. Salient information associated with the mechanical properties of the membrane tether can thus be obtained. Tethers can be pulled from the cell membrane at different holding potentials, and the tether force response can be measured while changing transmembrane potential. Experimental results from outer hair cells and human embryonic kidney cells are presented.

  5. Contact Allergy to Hair Dyes

    OpenAIRE

    Marie-Louise Anna Schuttelaar; Tatiana Alexandra Vogel

    2016-01-01

    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....

  6. 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.

  7. Hair whorls in the horse

    OpenAIRE

    Baxová, Edita

    2012-01-01

    SUMMARY This bachelor thesis is focused primaly on an assessment of hair whirls in the horses due to thein temperament, nature, behavior and movement mechanics. There is explained the biology of the hair growth, its structure, composition and pigmentation and its functions which are very important for the whole organism in the literature review. It is also explained how the hair whirls arise and why the breeders have long been showing interest and attach great importance to them....

  8. 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.

  9. Optical properties of human hair

    Science.gov (United States)

    Altshuler, Gregory B.; Ilyasov, Ildar K.; Prikhodko, Constantin V.

    1995-01-01

    Optical properties of human hair are the subject of great interest for the realization of any possible cosmetic applications. This paper represents the results of hair microstructure as an optical substance investigation, indicates melanin and keratin absorption spectra, and shows experimentally discovered anisotropia of optical properties of human hair. Radiation weakening coefficient value at the range from 450 up to 800 nm is estimated. Thresholds of hair destruction by Nd, Ho, Cu, and Er laser radiation are obtained. Perspectives of laser application for epilation and other medical purposes are evaluated.

  10. 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…

  11. 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

  12. Removing Pubic Hair (For Young Women)

    Science.gov (United States)

    ... Gynecology Medical Conditions Nutrition & Fitness Emotional Health Removing Pubic Hair Posted under Health Guides . Updated 7 October 2015. + ... safety guidelines if you decide to remove pubic hair. Removing pubic hair is a personal preference. Some girls trim ...

  13. Excessive or unwanted hair in women

    Science.gov (United States)

    Hypertrichosis; Hirsutism; Hair - excessive (women); Excessive hair in women; Hair - women - excessive or unwanted ... Women normally produce low levels of male hormones (androgens). If your body makes too much of this ...

  14. 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

  15. 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...

  16. 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.…

  17. Frequency-place compression and expansion in cochlear implant listeners

    NARCIS (Netherlands)

    Baskent, D; Shannon, RV

    2004-01-01

    In multichannel cochlear implants, low frequency information is delivered to apical cochlear locations while high frequency information is delivered to more basal locations, mimicking the normal acoustic tonotopic organization of the auditory nerves. In clinical practice; little attention has been p

  18. 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…

  19. 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…

  20. 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…

  1. Emotion Understanding in Deaf Children with a Cochlear Implant

    Science.gov (United States)

    Wiefferink, Carin H.; Rieffe, Carolien; Ketelaar, Lizet; De Raeve, Leo; Frijns, Johan H. M.

    2013-01-01

    It is still largely unknown how receiving a cochlear implant affects the emotion understanding in deaf children. We examined indices for emotion understanding and their associations with communication skills in children aged 2.5-5 years, both hearing children (n = 52) and deaf children with a cochlear implant (n = 57). 2 aspects of emotion…

  2. 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.

  3. Review of hair follicle dermal cells

    OpenAIRE

    Yang, Chao-Chun; Cotsarelis, George

    2010-01-01

    Hair follicle stem cells in the epithelial bulge are responsible for the continual regeneration of the hair follicle during cycling. The bulge cells reside in a niche composed of dermal cells. The dermal compartment of the hair follicle consists of the dermal papilla and dermal sheath. Interactions between hair follicle epithelial and dermal cells are necessary for hair follicle morphogenesis during development and in hair reconstitution assays. Dermal papilla and dermal sheath cells express ...

  4. The Hearing Outcomes of Cochlear Implantation in Waardenburg Syndrome

    Directory of Open Access Journals (Sweden)

    Hajime Koyama

    2016-01-01

    Full Text Available Objectives. This study aimed to determine the feasibility of cochlear implantation for sensorineural hearing loss in patients with Waardenburg syndrome. Method. A retrospective chart review was performed on patients who underwent cochlear implantation at the University of Tokyo Hospital. Clinical classification, genetic mutation, clinical course, preoperative hearing threshold, high-resolution computed tomography of the temporal bone, and postoperative hearing outcome were assessed. Result. Five children with Waardenburg syndrome underwent cochlear implantation. The average age at implantation was 2 years 11 months (ranging from 1 year 9 months to 6 years 3 months. Four patients had congenital profound hearing loss and one patient had progressive hearing loss. Two patients had an inner ear malformation of cochlear incomplete partition type 2. No surgical complication or difficulty was seen in any patient. All patients showed good hearing outcome postoperatively. Conclusion. Cochlear implantation could be a good treatment option for Waardenburg syndrome.

  5. The Hearing Outcomes of Cochlear Implantation in Waardenburg Syndrome.

    Science.gov (United States)

    Koyama, Hajime; Kashio, Akinori; Sakata, Aki; Tsutsumiuchi, Katsuhiro; Matsumoto, Yu; Karino, Shotaro; Kakigi, Akinobu; Iwasaki, Shinichi; Yamasoba, Tatsuya

    2016-01-01

    Objectives. This study aimed to determine the feasibility of cochlear implantation for sensorineural hearing loss in patients with Waardenburg syndrome. Method. A retrospective chart review was performed on patients who underwent cochlear implantation at the University of Tokyo Hospital. Clinical classification, genetic mutation, clinical course, preoperative hearing threshold, high-resolution computed tomography of the temporal bone, and postoperative hearing outcome were assessed. Result. Five children with Waardenburg syndrome underwent cochlear implantation. The average age at implantation was 2 years 11 months (ranging from 1 year 9 months to 6 years 3 months). Four patients had congenital profound hearing loss and one patient had progressive hearing loss. Two patients had an inner ear malformation of cochlear incomplete partition type 2. No surgical complication or difficulty was seen in any patient. All patients showed good hearing outcome postoperatively. Conclusion. Cochlear implantation could be a good treatment option for Waardenburg syndrome. PMID:27376080

  6. Cochlear imaging in the era of cochlear implantation : from silence to sound

    NARCIS (Netherlands)

    Verbist, Berit Michaela

    2010-01-01

    Cochlear implants (CIs) are a well accepted treatment for hearing impaired people. In pre- and postoperative assessment of CI-candidates imaging plays an important role to analyze anatomy, rule out pathology and determine intracochlear positioning and integrity of the implant. Developments in CI-des

  7. Hair loss in women.

    Science.gov (United States)

    Camacho-Martínez, Francisco M

    2009-03-01

    Female pattern hair loss (FPHL) is a clinical problem that is becoming more common in women. Female alopecia with androgen increase is called female androgenetic alopecia (FAGA) and without androgen increase is called female pattern hair loss. The clinical picture of typical FAGA begins with a specific "diffuse loss of hair from the parietal or frontovertical areas with an intact frontal hairline." Ludwig called this process "rarefaction." In Ludwig's classification of hair loss in women, progressive type of FAGA, 3 patterns were described: grade I or minimal, grade II or moderate, and grade III or severe. Ludwig also described female androgenetic alopecia with male pattern (FAGA.M) that should be subclassified according to Ebling's or Hamilton-Norwood's classification. FAGA.M may be present in 4 conditions: persistent adrenarche syndrome, alopecia caused by an adrenal or an ovarian tumor, posthysterectomy, and as an involutive alopecia. A more recent classification (Olsen's classification of FPHL) proposes 2 types: early- and late-onset with or without excess of androgens in each. The diagnosis of FPHL is made by clinical history, clinical examination, wash test, dermoscopy, trichoscan, trichograms and laboratory test, especially androgenic determinations. Topical treatment of FPHL is with minoxidil, 2-5% twice daily. When FPHL is associated with high levels of androgens, systemic antiandrogenic therapy is needed. Persistent adrenarche syndrome (adrenal SAHA) and alopecia of adrenal hyperandrogenism is treated with adrenal suppression and antiandrogens. Adrenal suppression is achieved with glucocorticosteroids. Antiandrogens therapy includes cyproterone acetate, drospirenone, spironolactone, flutamide, and finasteride. Excess release of ovarian androgens (ovarian SAHA) and alopecia of ovarian hyperandrogenism is treated with ovarian suppression and antiandrogens. Ovarian suppression includes the use of contraceptives containing an estrogen, ethinylestradiol, and a

  8. The preshaving protocol in body hair-to-scalp transplant to identify hair in anagen phase

    Directory of Open Access Journals (Sweden)

    Poswal Arvind

    2010-01-01

    Full Text Available Introduction: The use of body donor hair for transplanting to the bald scalp is termed body hair transplant. In recent times, robust body hair has been used as an adjunct to scalp donor hair to augment the donor hair supply. A large percentage of body hair are in telogen and, as single hair units. Aims: To devise a non invasive protocol to identify the body donor hair in anagen phase prior to extraction. Materials and Methods: Hairs are shaved flush with the skin, four days prior to extraction. On fourth day, the actively growing hair follicles as well as non growing hairs were extracted and phase of hair growth determined. Results: Nineteen out 22 extracted hair follicles in nongrowing phase were found to be the telogen phase. Conclusion: Preshaving the body donor areas is a simple non invasive method of isolating the hair in anagen phase.

  9. 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. PMID:27319056

  10. 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.

  11. Proteome analysis of chick embryonic cerebrospinal fluid.

    Science.gov (United States)

    Parada, Carolina; Gato, Angel; Aparicio, Mariano; Bueno, David

    2006-01-01

    During early stages of embryo development, the brain cavity is filled with embryonic cerebrospinal fluid (E-CSF), a complex fluid containing different protein fractions that contributes to the regulation of the survival, proliferation and neurogenesis of the neuroectodermal stem cells. Using 2-DE, protein sequencing and database searches, we identified and analyzed the proteome of the E-CSF from chick embryos (Gallus gallus). We identified 26 different gene products, including proteins related to the extracellular matrix, proteins associated with the regulation of osmotic pressure and metal transport, proteins related to cell survival, MAP kinase activators, proteins involved in the transport of retinol and vitamin D, antioxidant and antimicrobial proteins, intracellular proteins and some unknown proteins. Most of these gene products are involved in the regulation of developmental processes during embryogenesis in systems other than E-CSF. Interestingly, 14 of them are also present in adult human CSF proteome, and it has been reported that they are altered in the CSF of patients suffering neurodegenerative diseases and/or neurological disorders. Understanding these molecules and the mechanisms they control during embryonic neurogenesis is a key contribution to the general understanding of CNS development, and may also contribute to greater knowledge of these human diseases. PMID:16287170

  12. 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.

  13. "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…

  14. 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

  15. 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. PMID:19834437

  16. Human Hair: An Educational Tool.

    Science.gov (United States)

    Wells, John

    1983-01-01

    Briefly describes some of the more recent developments in the use of human hairs for such instructional purposes as observing barr bodies and chromosomes, and for culturing to produce cells of both epithelial and fibroblastic morphology. Three main hair categories are also described. (JN)

  17. Light Microscopy of the Hair: A Simple Tool to “Untangle” Hair Disorders

    OpenAIRE

    Adya, Keshavmurthy A; Inamadar, Arun C.; Palit, Aparna; Shivanna, Ragunatha; Deshmukh, Niranjan S

    2011-01-01

    Light microscopy of the hair forms an important bedside clinical tool for the diagnosis of various disorders affecting the hair. Hair abnormalities can be seen in the primary diseases affecting the hair or as a secondary involvement of hair in diseases affecting the scalp. Hair abnormalities also form a part of various genodermatoses and syndromes. In this review, we have briefly highlighted the light microscopic appearance of various infectious and non-infectious conditions affecting the hair.

  18. 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

  19. Cochlear Micromechanics (Part II): A moderated discussion

    Science.gov (United States)

    Gummer, Anthony W.; Mountain, David C.

    2015-12-01

    The following is an edited transcript of a recorded discussion session on the topic of "Cochlear Micromechanics". The discussion, moderated by the authors, took place at the 12th International Workshop on the Mechanics of Hearing held at Cape Sounio, Greece, in June 2014. All participants knew that the session was being recorded. In view of both the spontaneous nature of the discussion and the editing, however, this transcript may not represent the considered or final views of the participants, and may not represent a consensus of experts in the field. The reader is advised to consult additional independent publications.

  20. Cochlear Micromechanics (Part I): A moderated discussion

    Science.gov (United States)

    Neely, Stephen T.

    2015-12-01

    The following is an edited transcript of a recorded discussion session on the topic of "Cochlear Micromechanics". The discussion, moderated by the author, took place at the 12th International Workshop on the Mechanics of Hearing held at Cape Sounio, Greece, in June 2014. All participants knew that the session was being recorded. In view of both the spontaneous nature of the discussion and the editing, however, this transcript may not represent the considered or final views of the participants, and may not represent a consensus of experts in the field. The reader is advised to consult additional independent publications.

  1. 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.

  2. Cochlear implant candidates: assessment with CT and MR imaging.

    Science.gov (United States)

    Harnsberger, H R; Dart, D J; Parkin, J L; Smoker, W R; Osborn, A G

    1987-07-01

    Eighty-seven patients with severe to profound hearing loss were evaluated for possible placement of a multichannel cochlear implant hearing device. After initial clinical screening, 42 patients underwent computed tomographic (CT) examination. Five of these patients were also examined with magnetic resonance (MR) imaging. Twenty-two patients received implants. CT of the middle and inner ear was normal in 24 patients (57.1%) and showed labyrinthine ossification in 12 (28.6%), cochlear or fenestral otosclerosis (or both) in four (9.5%), and congenital cochlear malformation in two (4.8%). The information provided by CT was used to (a) exclude patients in whom multichannel cochlear implantation would most likely be unsuccessful (owing to obliterative labyrinthine ossification, or congenital cochlear malformation, severe cochlear, or fenestral otosclerosis), (b) help select the best ear for implantation, and (c) provide a preoperative picture of normal variants and avoidable surgical pitfalls. MR experience is limited but assessment of the size of the cochlear nerve and the membranous labyrinth is possible with this modality and may provide additional information in the evaluation of these patients. PMID:3108956

  3. 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

  4. 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

  5. Enhanced learning of natural visual sequences in newborn chicks.

    Science.gov (United States)

    Wood, Justin N; Prasad, Aditya; Goldman, Jason G; Wood, Samantha M W

    2016-07-01

    To what extent are newborn brains designed to operate over natural visual input? To address this question, we used a high-throughput controlled-rearing method to examine whether newborn chicks (Gallus gallus) show enhanced learning of natural visual sequences at the onset of vision. We took the same set of images and grouped them into either natural sequences (i.e., sequences showing different viewpoints of the same real-world object) or unnatural sequences (i.e., sequences showing different images of different real-world objects). When raised in virtual worlds containing natural sequences, newborn chicks developed the ability to recognize familiar images of objects. Conversely, when raised in virtual worlds containing unnatural sequences, newborn chicks' object recognition abilities were severely impaired. In fact, the majority of the chicks raised with the unnatural sequences failed to recognize familiar images of objects despite acquiring over 100 h of visual experience with those images. Thus, newborn chicks show enhanced learning of natural visual sequences at the onset of vision. These results indicate that newborn brains are designed to operate over natural visual input. PMID:27079969

  6. 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.

  7. 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)...

  8. Efficiency of staining hair with indocyanine green

    Science.gov (United States)

    Kulyabina, Tatyana V.; Kochubey, Vyacheslav I.

    2005-06-01

    The efficiency of staining hair with indocyanine green (ICG) solution depending on type of hair, natural color, staining time and other parameters was investigated. Bonding ICG with hair material occurs due to interaction between ICG molecules and keratinocyte albumin. The penetration of ICG dye into hair meets with difficulties owing to surface protective layer.

  9. Changes in Pitch with a Cochlear Implant Over Time

    OpenAIRE

    Reiss, Lina A.J.; Turner, Christopher W.; Erenberg, Sheryl R.; Gantz, Bruce J

    2007-01-01

    In the normal auditory system, the perceived pitch of a tone is closely linked to the cochlear place of vibration. It has generally been assumed that high-rate electrical stimulation by a cochlear implant electrode also evokes a pitch sensation corresponding to the electrode’s cochlear place (“place” code) and stimulation rate (“temporal” code). However, other factors may affect electric pitch sensation, such as a substantial loss of nearby nerve fibers or even higher-level perceptual changes...

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. MR imaging of cochlear implant candidates

    International Nuclear Information System (INIS)

    This paper reports on the value of diagnostic imaging in the workup of patients for possible placement of a multichannel intracochlear hearing device. Forty-five candidates for cochlear implantation were examined with both CT and MR imaging. In 32 adult patients coronal and axial T2-weighted spin-echo sequences were performed. In 10 patients, we used a T2*-weighted gradient-echo three-dimensional sequence with axial presaturation instead. Three children were examined with an ultrafast snapshot sequence for scout viewing, followed by a T2-weighted axial half-Fourier spin-echo sequence. In 36 patients we found the cochlea to be patent. Thirty-three of these patients successfully received an implant device. Three patients still await surgery. Six patients showed pathologic conditions in at least one ear at CT and MR alone. In 3 patients there was evidence of bony occulsion of the cochlear duct at CT; MR revealed a reduced signal intensity in the cochlea as well. Two patients with normal CT results showed abnormal conditions at MR imaging (reduced signal on T2-weighted images) and were not operated on

  16. Complications in hair restoration surgery.

    Science.gov (United States)

    Perez-Meza, David; Niedbalski, Robert

    2009-02-01

    Hair loss affects more than 1.2 billion people worldwide. As the technology and artistry of hair restoration surgery has improved including natural results, so too has the popularity of this procedure. As with any other surgical procedure, complications may occur and this presents a major challenge for the surgeon and the patient. This article provides an overview of the complications most likely to occur during the pre, intra, and postoperative periods with modern hair transplant surgery (single follicular unit or multifollicular unit) including scalp surgery, and discusses their treatment and most importantly their prevention. PMID:19185800

  17. Hair dye poisoning and rhabdomyolysis.

    Science.gov (United States)

    Bokutz, Munira; Nasir, Nosheen; Mahmood, Faisal; Sajid, Sara

    2015-04-01

    Hair dye ingestion is a rare cause of toxicity in Pakistan. We are presenting the case report of a 55 year old male who presented with accidental hair dye ingestion and developed laryngeal oedema requiring emergent tracheostomy. He had also developed aspiration pneumonitis and chemical oesophagitis. However, the most alarming manifestation was rhabdomyolysis. Hair dye toxicity can be fatal if not recognized early. There is no antidote available. Rhabdomyolysis is a complication and needs to be managed aggressively in order to prevent long term morbidity. PMID:25976581

  18. 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.

  19. Trace analysis in human hair

    International Nuclear Information System (INIS)

    The hair has been used as a readily available tissue for the trace analysis. It can supply the medical diagnosis and environmental studied. Hair tissue is, potentially, a remarkable diagnostic tool to complement blood serum and urine analysis. The CDTN/CNEN-BH has a large experience on determining the elements within the various ranges of concentration in several kinds of matrices by using neutron activation and atomic absorption spectrometry. This experience has made possible the development of methods using hair so as to determine the detections limits of Al, Cr, Cu, Hg, K, Mn and Zn. (author)

  20. Do You Have Hair Loss or Hair Shedding?

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases Cosmetic treatments Dry / sweaty skin Eczema / dermatitis Hair and scalp ...

  1. Controversy: Synthetic Hairs and their Role in Hair Restoration?

    OpenAIRE

    Mysore, Venkataram

    2010-01-01

    The subject of artifical hair fibers is controversial, in view of their chequered history and the ban by federal drug administration (FDA) on their use. This article analyzes different aspects of their use.

  2. 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...

  3. Generalization of visual regularities in newly hatched chicks (Gallus gallus).

    Science.gov (United States)

    Santolin, Chiara; Rosa-Salva, Orsola; Regolin, Lucia; Vallortigara, Giorgio

    2016-09-01

    Evidence of learning and generalization of visual regularities in a newborn organism is provided in the present research. Domestic chicks have been trained to discriminate visual triplets of simultaneously presented shapes, implementing AAB versus ABA (Experiment 1), AAB versus ABB and AAB versus BAA (Experiment 2). Chicks distinguished pattern-following and pattern-violating novel test triplets in all comparisons, showing no preference for repetition-based patterns. The animals generalized to novel instances even when the patterns compared were not discriminable by the presence or absence of reduplicated elements or by symmetry (e.g., AAB vs. ABB). These findings represent the first evidence of learning and generalization of regularities at the onset of life in an animal model, revealing intriguing differences with respect to human newborns and infants. Extensive prior experience seems to be unnecessary to drive the process, suggesting that chicks are predisposed to detect patterns characterizing the visual world. PMID:27287627

  4. New insights into cochlear sound encoding.

    Science.gov (United States)

    Moser, Tobias; Vogl, Christian

    2016-01-01

    The inner ear uses specialized synapses to indefatigably transmit sound information from hair cells to spiral ganglion neurons at high rates with submillisecond precision. The emerging view is that hair cell synapses achieve their demanding function by employing an unconventional presynaptic molecular composition. Hair cell active zones hold the synaptic ribbon, an electron-dense projection made primarily of RIBEYE, which tethers a halo of synaptic vesicles and is thought to enable a large readily releasable pool of vesicles and to contribute to its rapid replenishment. Another important presynaptic player is otoferlin, coded by a deafness gene, which assumes a multi-faceted role in vesicular exocytosis and, when disrupted, causes auditory synaptopathy. A functional peculiarity of hair cell synapses is the massive heterogeneity in the sizes and shapes of excitatory postsynaptic currents. Currently, there is controversy as to whether this reflects multiquantal release with a variable extent of synchronization or uniquantal release through a dynamic fusion pore. Another important question in the field has been the precise mechanisms of coupling presynaptic Ca (2+) channels and vesicular Ca (2+) sensors. This commentary provides an update on the current understanding of sound encoding in the cochlea with a focus on presynaptic mechanisms. PMID:27635230

  5. New insights into cochlear sound encoding

    Science.gov (United States)

    Moser, Tobias; Vogl, Christian

    2016-01-01

    The inner ear uses specialized synapses to indefatigably transmit sound information from hair cells to spiral ganglion neurons at high rates with submillisecond precision. The emerging view is that hair cell synapses achieve their demanding function by employing an unconventional presynaptic molecular composition. Hair cell active zones hold the synaptic ribbon, an electron-dense projection made primarily of RIBEYE, which tethers a halo of synaptic vesicles and is thought to enable a large readily releasable pool of vesicles and to contribute to its rapid replenishment. Another important presynaptic player is otoferlin, coded by a deafness gene, which assumes a multi-faceted role in vesicular exocytosis and, when disrupted, causes auditory synaptopathy. A functional peculiarity of hair cell synapses is the massive heterogeneity in the sizes and shapes of excitatory postsynaptic currents. Currently, there is controversy as to whether this reflects multiquantal release with a variable extent of synchronization or uniquantal release through a dynamic fusion pore. Another important question in the field has been the precise mechanisms of coupling presynaptic Ca 2+ channels and vesicular Ca 2+ sensors. This commentary provides an update on the current understanding of sound encoding in the cochlea with a focus on presynaptic mechanisms. PMID:27635230

  6. 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

  7. 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

  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. Solubility of Structurally Complicated Materials: 3. Hair

    OpenAIRE

    Horvath, Ari L.

    2009-01-01

    Hair is composed of proteins, lipids, water, and small amounts of trace elements. All proteins in animal and human bodies are built from permutations of amino acid molecules in a polypeptide string. The polypeptide chains of protein keratin are organized into filaments in hair cells. Hair is one of the most difficult proteins to digest or solubilize. Among the most common dissolving procedures for hair are acidic, alkaline, and enzymatic hydrolysis. For the analysis of hair, the solid samples...

  10. Keratins and lipids in ethnic hair

    OpenAIRE

    Cruz, Célia F.; Fernandes, Margarida M.; Gomes, Andreia; Coderch, L.; Martí, M.; Méndez, Sandra; Gales, Luís; Azóia, Nuno G.; Shimanovich, Ulyana; Paulo, Artur Cavaco

    2013-01-01

    Human hair has an important and undeniable relevance in society due to its important role in visual appearance and social communication. Hair is mainly composed of structural proteins, mainly keratin and keratin associated proteins, and lipids. Herein, we report a comprehensive study of the content and distribution of the lipids among ethnic hair, African, Asian and Caucasian hair. More interestingly, we also report the study of the interaction between those two main components of hair, speci...

  11. Synchrotron radiation XRF analysis of human hair

    International Nuclear Information System (INIS)

    The trace elements distribution along scalp hair is measured by SR excited XRF. The results of repeat scanning of a single hair and a strand of five hairs from the same person show that precision of the experiments is very well. The content change tendencies of most elements for 3 different hairs taken from the same area of one person are basically the same and a similar concentration gradient is presented. But the tendencies for different person's hair are quite different

  12. 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

  13. Music Perception of Cochlear Implant Recipients with Implications for Music Instruction: A Review of Literature.

    Science.gov (United States)

    Hsiao, Feilin; Gfeller, Kate

    2012-03-23

    This review of literature presents a systematic analysis of the capabilities and limitations of cochlear implant recipients regarding music perception. Specifically, it a) analyzes individual components of music (e.g., rhythm, timbre, and pitch) as they interface with the technical characteristics of cochlear implants and the perceptual abilities of cochlear implant recipients; and b) describes accommodations for music instruction that support successful participation of children with cochlear implants. This article consolidates research studies from various disciplines (audiology, hearing science, speech-language pathology, cochlear implants, and music therapy) to provide practical recommendations for educators in fostering the musical growth of children with cochlear implants. PMID:23469365

  14. 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

  15. 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.

  16. Quo vadis, hair cell regeneration?

    OpenAIRE

    Brigande, John V; Heller, Stefan

    2009-01-01

    Hearing loss is a global health problem with profound socioeconomic impact. We contend that acquired hearing loss is mainly a modern disorder caused by man-made noise and modern drugs, among other causes. These factors, combined with increasing lifespan, have exposed a deficit in cochlear self-regeneration that was irrelevant for most of mammalian evolution. Nevertheless, the mammalian cochlea has evolved from phylogenetically older structures, which do have the capacity for self-repair. More...

  17. Language understanding and vocabulary of early cochlear implanted children

    DEFF Research Database (Denmark)

    Percy-Smith, L; Busch, GW; Sandahl, M;

    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....

  18. 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.

  19. Evaluation of vestibular function following cochlear implant surgery

    Directory of Open Access Journals (Sweden)

    Masoud Motesaddi Zandi

    2009-04-01

    Full Text Available Introduction: There are contradictory reports regarding vestibular function after cochlear implant surgery. In this study, we evaluated the influence of cochlear implant surgery on vestibular function by comparing the results of caloric test in both ears of patients who received implants. Materials and Methods: 24 adult patients who had undergone cochlear implant surgery at least 6 months earlier, were participated in this study. Caloric test with the stimulus of cold and warm water was performed on both ears of each patient and results were compared with each other regarding unilateral weakness, directional preponderance and areflexia. Results: The differences between two ears regarding directional preponderance, unilateral weakness and areflexia were not statistically significant. Conclusion: It seems the pathological cause of deafness is a more influential factor on vestibular dysfunction than the damage following cochlear implant surgery.

  20. Human cochlear tuning estimates from stimulus-frequency otoacoustic emissions

    DEFF Research Database (Denmark)

    Bentsen, Thomas; Harte, James; Dau, Torsten

    2011-01-01

    Two objective measures of human cochlear tuning, using stimulus-frequency otoacoustic emissions (SFOAE), have been proposed. One measure used SFOAE phase-gradient delay and the other twotone suppression (2TS) tuning curves. Here, it is hypothesized that the two measures lead to different frequency......-of-tuning curves was observed for experiment 2, consistent with objective and behavioural estimates from the literature. Most importantly, the absolute difference between the two tuning estimates was very large and statistically significant. It is argued that the 2TS estimates of cochlear tuning likely represents...... the underlying properties of the suppression mechanism, and not necessarily cochlear tuning. Thus the phase-gradient delay estimate is the most likely one to reflect cochlear tuning....

  1. Hair Loss in New Moms

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases Cosmetic treatments Dry / sweaty skin Eczema / dermatitis Hair and scalp ...

  2. 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.

  3. 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. 

  4. 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

  5. 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.

  6. Variability of the mental representation of the cochlear anatomy during cochlear implantation.

    Science.gov (United States)

    Torres, Renato; Kazmitcheff, Guillaume; Bernardeschi, Daniele; De Seta, Daniele; Bensimon, Jean Loup; Ferrary, Evelyne; Sterkers, Olivier; Nguyen, Yann

    2016-08-01

    The aim of this study was to assess the mental representation of the insertion axis of surgeons with different degrees of experience, and reproducibility of the insertion axis in repeated measures. A mastoidectomy and a posterior tympanotomy were prepared in five different artificial temporal bones. A cone-beam CT was performed for each temporal bone and the data were registered on a magnetic navigation system. In these five temporal bones, 16 surgeons (3 experts; >50 cochlear implant surgery/year; 7 fellows with few cochlear implant experience, and 6 residents) were asked to determine the optimal insertion axis according to their mental representation. Compared to a planned ideal axis, the insertion axis was better determined by the experts with higher accuracy (axial: 7° ± 1.5°, coronal: 6° ± 1.5°) than fellows (axial: 14° ± 1.7°, coronal: 13° ± 1.7°; p scala tympani can be observed due to the complexity of the temporal bone anatomy and lack of landmarks to determine scala tympani orientation. Navigation systems can be used to evaluate and improve mental representation of the insertion axis to the scala tympani for cochlear implant surgery. PMID:26324880

  7. Hair transplant: a basic review.

    Science.gov (United States)

    Kite, Amy; Lucas, Valentina S

    2015-01-01

    The hairline is an important aspect of beauty. Loss of the hairline can contribute to poor self-esteem. Alopecia, or hair loss, has many different causes and can have devastating outcomes to the patient. The plastic surgery team may play a role in restoring the hairline and thus improving one's image of self. This article identifies the different causes of hair loss and then reviews steps and options for hairline restoration. PMID:26020470

  8. The Hearing Outcomes of Cochlear Implantation in Waardenburg Syndrome

    OpenAIRE

    Koyama, Hajime; Kashio, Akinori; Sakata, Aki; Tsutsumiuchi, Katsuhiro; Matsumoto, Yu; Karino, Shotaro; Kakigi, Akinobu; Iwasaki, Shinichi; Yamasoba, Tatsuya

    2016-01-01

    Objectives. This study aimed to determine the feasibility of cochlear implantation for sensorineural hearing loss in patients with Waardenburg syndrome. Method. A retrospective chart review was performed on patients who underwent cochlear implantation at the University of Tokyo Hospital. Clinical classification, genetic mutation, clinical course, preoperative hearing threshold, high-resolution computed tomography of the temporal bone, and postoperative hearing outcome were assessed. Result. F...

  9. Audiological outcomes of cochlear implantation in Waardenburg Syndrome

    OpenAIRE

    Magalhães, Ana Tereza de Matos; Samuel, Paola Angélica; Goffi-Gomez, Maria Valeria Schimdt; Tsuji, Robinson Koji; Brito, Rubens; Bento, Ricardo Ferreira

    2013-01-01

    Summary Introduction: The most relevant clinical symptom in Waardenburg syndrome is profound bilateral sensorioneural hearing loss. Aim: To characterize and describe hearing outcomes after cochlear implantation in patients with Waardenburg syndrome to improve preoperative expectations. Method: This was an observational and retrospective study of a series of cases. Children who were diagnosed with Waardenburg syndrome and who received a multichannel cochlear implant between March 1999 and July...

  10. 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

  11. Bilingualism: A Pearl to Overcome Certain Perils of Cochlear Implants

    OpenAIRE

    Humphries, Tom; Kushalnagar, Poorna; Mathur, Gaurav; Napoli, Donna Jo; Padden, Carol; Rathmann, Christian; Smith, Scott

    2014-01-01

    Cochlear implants (CI) have demonstrated success in improving young deaf children’s speech and low-level speech awareness across a range of auditory functions, but this success is highly variable, and how this success correlates to high-level language development is even more variable. Prevalence on the success rate of CI as an outcome for language development is difficult to obtain because studies vary widely in methodology and variables of interest, and because not all cochlear implant tech...

  12. 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

  13. Maximizing Cochlear Implant Patients’ Performance with Advanced Speech Training Procedures

    OpenAIRE

    Fu, Qian-Jie; Galvin, John J.

    2007-01-01

    Advances in implant technology and speech processing have provided great benefit to many cochlear implant patients. However, some patients receive little benefit from the latest technology, even after many years’ experience with the device. Moreover, even the best cochlear implant performers have great difficulty understanding speech in background noise, and music perception and appreciation remain major challenges. Recent studies have shown that targeted auditory training can significantly i...

  14. 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.

  15. 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

  16. Tinnitus before and 6 Months after Cochlear Implantation

    OpenAIRE

    Kompis, M; Pelizzone, M.; Dillier, N; J. Allum; Demin, N; Senn, P.

    2012-01-01

    In this prospective multicenter study, tinnitus loudness and tinnitus-related distress were investigated in 174 cochlear implant (CI) candidates who underwent CI surgery at a Swiss cochlear implant center. All subjects participated in two session, one preoperatively and one 6 months after device activation. In both sessions, tinnitus loudness was assessed using a visual analogue scale and tinnitus distress using a standardized tinnitus questionnaire. The data were compared with unaided pre- a...

  17. Cochlear re-implantation: lessons learnt and the way ahead.

    Science.gov (United States)

    Patnaik, Uma; Sikka, Kapil; Agarwal, Shivani; Kumar, Rakesh; Thakar, Alok; Sharma, Suresh C

    2016-06-01

    Conclusion A cochlear re-implantation procedure is undesirable; however, the cochlear implant surgeon may have to perform a re-implantation procedure occasionally for various reasons. Following standard techniques, implant performance comparable with primary implantation may be achieved. Objective To study the causes and outcomes of cochlear re-implantation in an Asian Indian population. Study design Retrospective analysis of clinical charts over an 18-year period with prospective follow-up of patients. Methods The charts of 534 patients, who underwent cochlear implant, at an Otorhinolaryngology institutional Centre, from January 1997 to January 2015 were studied. Of these, the charts of 18 patients who underwent cochlear re-implantation were studied. The causes and audiological and speech outcomes were analysed. Results Eighteen patients (3.4%) underwent cochlear re-implantation for various reasons. The commonest indication was device failure in seven patients (39%), followed by electrode extrusion in five (28%), trauma in three (11%), electrode migration in two (11%) and improper electrode placement in one (6%) patient. The audiological performance tests and speech tests either remained the same or improved from those achieved for patients undergoing primary implantation, in 87% patients. PMID:26898701

  18. The development of the Nucleus Freedom Cochlear implant system.

    Science.gov (United States)

    Patrick, James F; Busby, Peter A; Gibson, Peter J

    2006-12-01

    Cochlear Limited (Cochlear) released the fourth-generation cochlear implant system, Nucleus Freedom, in 2005. Freedom is based on 25 years of experience in cochlear implant research and development and incorporates advances in medicine, implantable materials, electronic technology, and sound coding. This article presents the development of Cochlear's implant systems, with an overview of the first 3 generations, and details of the Freedom system: the CI24RE receiver-stimulator, the Contour Advance electrode, the modular Freedom processor, the available speech coding strategies, the input processing options of Smart Sound to improve the signal before coding as electrical signals, and the programming software. Preliminary results from multicenter studies with the Freedom system are reported, demonstrating better levels of performance compared with the previous systems. The final section presents the most recent implant reliability data, with the early findings at 18 months showing improved reliability of the Freedom implant compared with the earlier Nucleus 3 System. Also reported are some of the findings of Cochlear's collaborative research programs to improve recipient outcomes. Included are studies showing the benefits from bilateral implants, electroacoustic stimulation using an ipsilateral and/or contralateral hearing aid, advanced speech coding, and streamlined speech processor programming. PMID:17172547

  19. 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.

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

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases Cosmetic treatments Dry / sweaty skin Eczema / dermatitis Hair and scalp ...

  1. Prestin-Dependence of Outer Hair Cell Survival and Partial Rescue of Outer Hair Cell Loss in PrestinV499G/Y501H Knockin Mice.

    Directory of Open Access Journals (Sweden)

    Mary Ann Cheatham

    Full Text Available A knockin (KI mouse expressing mutated prestinV499G/Y501H (499 prestin was created to study cochlear amplification. Recordings from isolated outer hair cells (OHC in this mutant showed vastly reduced electromotility and, as a consequence, reduced hearing sensitivity. Although 499 prestin OHCs were normal in stiffness and longer than OHCs lacking prestin, accelerated OHC death was unexpectedly observed relative to that documented in prestin knockout (KO mice. These observations imply an additional role of prestin in OHC maintenance besides its known requirement for mammalian cochlear amplification. In order to gain mechanistic insights into prestin-associated OHC loss, we implemented several interventions to improve survival. First, 499 prestin KI's were backcrossed to Bak KO mice, which lack the mitochondrial pro-apoptotic gene Bak. Because oxidative stress is implicated in OHC death, another group of 499 prestin KI mice was fed the antioxidant diet, Protandim. 499 KI mice were also backcrossed onto the FVB murine strain, which retains excellent high-frequency hearing well into adulthood, to reduce the compounding effect of age-related hearing loss associated with the original 499 prestin KIs. Finally, a compound heterozygous (chet mouse expressing one copy of 499 prestin and one copy of KO prestin was also created to reduce quantities of 499 prestin protein. Results show reduction in OHC death in chets, and in 499 prestin KIs on the FVB background, but only a slight improvement in OHC survival for mice receiving Protandim. We also report that improved OHC survival in 499 prestin KIs had little effect on hearing phenotype, reaffirming the original contention about the essential role of prestin's motor function in cochlear amplification.

  2. Aspects of Music with Cochlear Implants – Music Listening Habits and Appreciation in Danish Cochlear Implant Users

    OpenAIRE

    Petersen, Bjørn; Hansen, Mads; Sørensen, Stine Derdau; Ovesen, Therese; Vuust, Peter

    2014-01-01

    Cochlear implant users differ significantly from their normal hearing peerswhen it comes to perception of music. Several studies have shown thatstructural features – such as rhythm, timbre, and pitch – are transmitted lessaccurately through an implant. However, we cannot predict personalenjoyment of music solely as a function of accuracy of perception. But canmusic be pleasant with a cochlear implant at all? Our aim here was to gatherinformation of both music enjoyment and listening habits be...

  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. 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 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. PMID:24651081

  6. 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.

  7. Haemoproteus balearicae and other blood parasites of free-ranging Florida sandhill crane chicks

    Science.gov (United States)

    Dusek, R.J.; Spalding, M.G.; Forrester, Donald J.; Greiner, E.C.

    2004-01-01

    We obtained blood smears from 114 Florida sandhill crane (Grus canadensis pratensis) chicks in Osceola and Lake Counties, Florida, USA, during 1998-2000. Leucocytozoon grusi was observed in 11 (10%) chicks; Haemoproteus antigonis was observed in eight (7%) chicks; and three (3%) chicks were infected with Haemoproteus balearicae. One chick infected with H. balearicae suffered from severe anemia (packed cell volume=13%) and was later found moribund. At necropsy this bird also had severe anemia and damage to the heart possibly due to hypoxia. This is the first report of H. balearicae in free-ranging North American cranes. ?? Wildlife Disease Association 2004.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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…

  14. Influence of cochlear implantation on vestibular function.

    Science.gov (United States)

    Chen, Xiulan; Chen, Xiaohua; Zhang, Fan; Qin, Zhaobing

    2016-07-01

    Conclusion Vestibular function in patients can be damaged following cochlear implantation. Therefore, assessing the pre-operative vestibular status, carefully choosing the side of implantation, and preserving function by using minimally invasive surgical techniques are important. Objectives The aim of this study was to assess the influence of cochlear implantation on vestibular function in patients with severe and profound sensorineural hearing loss, and to analyze a possible correlation between the changes in vestibular testing and post-operative vestibular symptoms. Methods Thirty-four patients were evaluated for vestibular function using the cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP, respectively), and 29 patients underwent caloric tests pre-operatively and 4 weeks post-operatively. Results Before surgery, the cVEMPs were recorded bilaterally in 22 patients, unilaterally in eight patients, and absent bilaterally in four patients. The oVEMPs were recorded bilaterally in 19 patients, unilaterally in six patients, and absent bilaterally in nine patients. After implantation, the cVEMPs were absent in 10 patients and the oVEMPs were absent in seven patients on the implanted side. Caloric tests demonstrated canal paresis in 17 patients, and normal responses were recorded in 12 of the 29 patients pre-operatively. There was a significant decrease post-implantation in the ear implanted, with the exception of two patients. Two patients presented with vertigo and another two patients reported slight unsteadiness post-operatively, but all symptoms resolved within 7 days. The impaired vestibular function did not correlate with vestibular symptoms, age, or gender. Function on the contralateral side remained unaffected. PMID:27008103

  15. 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.

  16. 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.

  17. 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

  18. Using hair to screen for breast cancer

    Science.gov (United States)

    James, Veronica; Kearsley, John; Irving, Tom; Amemiya, Yoshiyuki; Cookson, David

    1999-03-01

    We have studied hair using fibre X-ray diffraction studies with synchrotron radiation and find that hair from breast-cancer patients has a different intermolecular structure to hair from healthy subjects. These changes are seen in all samples of scalp and pubic hair taken from women diagnosed with breast cancer. All the hair samples from women who tested positive for a mutation of the BRCA1 gene, which is associated with a higher risk of breast cancer, also show these changes. Because our results are so consistent, we propose that such hair analyses may be used as a simple, non-invasive screening method for breast cancer.

  19. 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.

  20. 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.

  1. 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.)

  2. 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

  3. California gull chicks raised near colony edges have elevated stress levels

    Science.gov (United States)

    Herring, Garth; Ackerman, Joshua T.

    2011-01-01

    Coloniality in nesting birds represents an important life history strategy for maximizing reproductive success. Birds nesting near the edge of colonies tend to have lower reproductive success than individuals nesting near colony centers, and offspring of edge-nesting parents may be impaired relative to those of central-nesting parents. We used fecal corticosterone metabolites in California gull chicks (Larus californicus) to examine whether colony size or location within the colony influenced a chick's physiological condition. We found that chicks being raised near colony edges had higher fecal corticosterone metabolite concentrations than chicks raised near colony centers, but that colony size (ranging from 150 to 11,554 nests) had no influence on fecal corticosterone levels. Fecal corticosterone metabolite concentrations also increased with chick age. Our results suggest that similarly aged California gull chicks raised near colony edges may be more physiologically stressed, as indicated by corticosterone metabolites, than chicks raised near colony centers.

  4. Cochlear implantation at the ear, nose and throat clinic of the Clinical center of Vojvodina

    OpenAIRE

    Komazec Zoran; Dankuc Dragan; Vlaški Ljiljana; Lemajić-Komazec Slobodanka; Nedeljkov Spomenka; Sokolovac Ivana

    2007-01-01

    Introduction. A cochlear implant is a small electronic device that can provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing. Cochlear implants bypass the damaged hearing systems and directly stimulate the auditory nerve. Signals generated by the implant are sent by way of the auditory nerve to the brain, which recognizes the signals as sound. Hearing through a cochlear implant differs from normal hearing and takes time to learn or relearn. Cochlear implantat...

  5. The Development of the Nucleus® Freedom™ Cochlear Implant System

    OpenAIRE

    Patrick, James F.; Busby, Peter A.; Gibson, Peter J.

    2006-01-01

    Cochlear Limited (Cochlear™) released the fourth-generation cochlear implant system, Nucleus® Freedom™, in 2005. Freedom is based on 25 years of experience in cochlear implant research and development and incorporates advances in medicine, implantable materials, electronic technology, and sound coding. This article presents the development of Cochlear's implant systems, with an overview of the first 3 generations, and details of the Freedom system: the CI24RE receiver-stimulator, the Contour ...

  6. The Effect of Cochlear Implantation on Education of Children with Hearing Disabilities in South Bohemia Region

    OpenAIRE

    MLÁDKOVÁ, Lucie

    2008-01-01

    The procedure of this qualitative research describes case studies of children with cochlear implants in the South Bohemia Region. It is a collection of information about their disabilities, families, social interactions and whole processes of rehabilitation before and after cochlear implantation. Its aim is to show how children with cochlear implants are successful and to facilitate the decision of each of their parents about the appropriate way of education for their own child with cochlear ...

  7. Hair restoration surgery: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Rose PT

    2015-07-01

    Full Text Available Paul T RoseHair Transplant Institute of Miami, Coral Gables, FL, USA Abstract: Hair loss is a common problem affecting both men and women. The most frequent etiology is androgenetic alopecia, but other causes of hair loss such as trauma, various dermatologic diseases, and systemic diseases can cause alopecia. The loss of hair can have profound effects on one’s self esteem and emotional well-being, as one’s appearance plays a role in the work place and interpersonal relationships. It is therefore not surprising that means to remedy hair loss are widely sought. Hair transplant surgery has become increasingly popular, and the results that we are able to create today are quite remarkable, providing a natural appearance when the procedure is performed well. In spite of this, hair transplant surgery is not perfect. It is not perfect because the hair transplant surgeon is still faced with challenges that prevent the achievement of optimal results. Some of these challenges include a limit to donor hair availability, hair survival, and ways to conceal any evidence of a surgical procedure having taken place. This article examines some of the most important challenges facing hair restoration surgery today and possible solutions to these challenges. Keywords: hair loss, alopecia, hair transplant, surgical procedure

  8. 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.

  9. 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. PMID:27341223

  10. 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...

  11. 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.

  12. 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.

  13. Image Registration of Cochlear µCT Data Using Heat Distribution Similarity

    DEFF Research Database (Denmark)

    Kjer, Hans Martin; Vera, Sergio; Fagertun, Jens;

    2015-01-01

    Better understanding of the anatomical variability of the human cochlear is important for the design and function of Cochlear Implants. Good non-rigid alignment of high-resolution cochlear μCT data is a challenging task. In this paper we study the use of heat distribution similarity between samples...

  14. 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 H; 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

  15. Patchy alopecia areata sparing gray hairs: a case series

    OpenAIRE

    Jia, Wei-Xue; Mao, Qiu-Xia; Xiao, Xue-Min; Li, Zhi-Liang; Yu, Rui-xing; Li, Cheng-Rang

    2014-01-01

    Alopecia areata is an unpredictable, non-scarring hair loss condition. Patchy alopecia areata sparing gray hairs is rare. Here we present 4 cases with patchy non-scarring hair loss, which attacked pigmented hairs only and spared gray hairs. It should be differentiated from vitiligo, colocalization of vitiligo and alopecia areata, and depigmented hair regrowth after alopecia areata.

  16. 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.

  17. Removing Pubic Hair (For Young Men)

    Science.gov (United States)

    ... Health Medical Conditions Nutrition & Fitness Emotional Health Removing Pubic Hair Posted under Health Guides . Updated 15 October 2014. +Related Content Some guys trim their pubic hair, others prefer to shave or wax, and most ...

  18. Genetics Home Reference: cartilage-hair hypoplasia

    Science.gov (United States)

    ... of each hair, which contains some of the pigment that contributes the hair's color, is missing. The ... have milder immune deficiency, experience infections of the respiratory system , ears, and sinuses . In particular, the chicken ...

  19. ROR1 is essential for proper innervation of auditory hair cells and hearing in humans and mice.

    Science.gov (United States)

    Diaz-Horta, Oscar; Abad, Clemer; Sennaroglu, Levent; Foster, Joseph; DeSmidt, Alexandra; Bademci, Guney; Tokgoz-Yilmaz, Suna; Duman, Duygu; Cengiz, F Basak; Grati, M'hamed; Fitoz, Suat; Liu, Xue Z; Farooq, Amjad; Imtiaz, Faiqa; Currall, Benjamin B; Morton, Cynthia Casson; Nishita, Michiru; Minami, Yasuhiro; Lu, Zhongmin; Walz, Katherina; Tekin, Mustafa

    2016-05-24

    Hair cells of the inner ear, the mechanosensory receptors, convert sound waves into neural signals that are passed to the brain via the auditory nerve. Little is known about the molecular mechanisms that govern the development of hair cell-neuronal connections. We ascertained a family with autosomal recessive deafness associated with a common cavity inner ear malformation and auditory neuropathy. Via whole-exome sequencing, we identified a variant (c.2207G>C, p.R736T) in ROR1 (receptor tyrosine kinase-like orphan receptor 1), cosegregating with deafness in the family and absent in ethnicity-matched controls. ROR1 is a tyrosine kinase-like receptor localized at the plasma membrane. At the cellular level, the mutation prevents the protein from reaching the cellular membrane. In the presence of WNT5A, a known ROR1 ligand, the mutated ROR1 fails to activate NF-κB. Ror1 is expressed in the inner ear during development at embryonic and postnatal stages. We demonstrate that Ror1 mutant mice are severely deaf, with preserved otoacoustic emissions. Anatomically, mutant mice display malformed cochleae. Axons of spiral ganglion neurons show fasciculation defects. Type I neurons show impaired synapses with inner hair cells, and type II neurons display aberrant projections through the cochlear sensory epithelium. We conclude that Ror1 is crucial for spiral ganglion neurons to innervate auditory hair cells. Impairment of ROR1 function largely affects development of the inner ear and hearing in humans and mice. PMID:27162350

  20. 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.

  1. 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.

  2. Hair Shaft Damage from Heat and Drying Time of Hair Dryer

    OpenAIRE

    Lee, Yoonhee; Kim, Youn-Duk; Hyun, Hye-Jin; Pi, Long-Quan; Jin, Xinghai; Lee, Won-Soo

    2011-01-01

    Background Hair dryers are commonly used and can cause hair damage such as roughness, dryness and loss of hair color. It is important to understand the best way to dry hair without causing damage. Objective The study assessed changes in the ultra-structure, morphology, moisture content, and color of hair after repeated shampooing and drying with a hair dryer at a range of temperatures. Methods A standardized drying time was used to completely dry each hair tress, and each tress was treated a ...

  3. The Effect of Age of Cochlear Implantation on the Improvement of the Auditory Performance in the Children Undergoing Cochlear Implantation

    Directory of Open Access Journals (Sweden)

    L Monshizadeh

    2013-03-01

    Full Text Available Introduction: Hearing is one of the premier human senses. Being deprived from hearing is not only being unable to hear the sounds, but it is also the disability to gain a lot of helpful experiences. Cochlear implantation is introduced worldwide in order to treat the severe to profound hearing loss. Therefore, the present study aims to determine the effect of age of cochlear implantation on improvement of the auditory performance. Methods: The present follow-up study was conducted on 96 children who had referred to Fars Cochlear Implantation Center. The patients’ information was gathered from their profiles both before and after the operation. In addition, the auditory performance score was obtained in 3 stages – 6 months, 1 year, and 2 years after the implantation – through the Cap test. Also, non-parametric tests of Fridman, Willcoxon, and Mann-Withney U were utilized in order to analyze the data of the study. Results: The mean of the children’s auditory performance 6 months, 1 year, and 2 years after the implantation was measured as 2.8+1.03, 4.36+1.04, and 5.34+1.02, respectively. Besides, the median of their auditory performance 6 months, 1 year, and 2 years after the implantation was calculated as 3, 5, and 5, respectively. Also, a statistically significant relationship was observed between the independent variable of age of cochlear implantation and the auditory performance score 6 months, 1 year, and 2 years after the implantation. Conclusion: In line with other studies conducted on the issue, the present study showed the improvement of the auditory performance in the children who benefited from cochlear implantation. Moreover, the results of the present study revealed that the age of cochlear implantation can be of great help in determining the candidates of cochlear implantation. In other words, it can be a major prognostic factor of the response to the treatment

  4. Hair transplantation: Standard guidelines of care

    OpenAIRE

    Patwardhan Narendra; Mysore Venkataram

    2008-01-01

    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 ...

  5. Female pattern hair loss: Current treatment concepts

    OpenAIRE

    Dinh, Quan Q; Sinclair, Rodney

    2007-01-01

    Fewer than 45% of women go through life with a full head of hair. Female pattern hair loss is the commonest cause of hair loss in women and prevalence increases with advancing age. Affected women may experience psychological distress and impaired social functioning. In most cases the diagnosis can be made clinically and the condition treated medically. While many women using oral antiandrogens and topical minoxidil will regrow some hair, early diagnosis and initiation of treatment is desirabl...

  6. Nanotechnology-Based Cosmetics for Hair Care

    OpenAIRE

    Jamie Rosen; Angelo Landriscina; Friedman, Adam J.

    2015-01-01

    Hair is a significant indicator of health and can have a major impact on an individual’s cosmetic appearance. Research within the cosmetics industry has revealed that when nanomaterials are engineered into hair care, they can enhance the benefits of active ingredients in order to improve hair cosmesis. Within the cosmetics arena, the unique size and intrinsic properties of nanoparticles can be tailored to target the hair follicle and shaft. This review aims to provide an overview of cosmetic ...

  7. Diffuse Hair Loss Induced by Sertraline Use

    OpenAIRE

    Yüksel Kıvrak; İbrahim Yağcı; Mehmet Fatih Üstündağ; Halil Özcan

    2015-01-01

    Hair loss is a rare side effect of psychotropic drugs. The most related drug class with this side effect is the mood stabilizers. Studies reporting the sertraline-induced alopecia are limited in number. Sertraline is a potent antidepressant which inhibits the serotonin reuptake from the presynaptic terminals selectively. The reason for hair loss could not be elucidated completely. Psychotropic drugs are usually considered to lead to hair loss through influencing the telogen phase of hair foll...

  8. A functional analysis of hair pulling.

    OpenAIRE

    Rapp, J T; Miltenberger, R G; Galensky, T L; Ellingson, S A; Long, E S

    1999-01-01

    We experimentally assessed the functions of hair pulling and hair manipulation of a 19-year-old woman (Kris) with moderate mental retardation and cerebral palsy. In Phase 1 a functional analysis revealed that Kris pulled and manipulated hair for the greatest amount of time in the alone condition, suggesting that the behaviors were maintained by some form of automatic reinforcement (Vaughan & Michael, 1982). In Phase 2 we assessed the nature of the sensory stimulation that maintained hair pull...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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. PMID:25962718

  14. 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.

  15. 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.

  16. Potassium Channel Activator Attenuates Salicylate-Induced Cochlear Hearing Loss Potentially Ameliorating Tinnitus

    Directory of Open Access Journals (Sweden)

    Wei eSun

    2015-04-01

    Full Text Available High dose sodium salicylate causes moderate, reversible hearing loss and tinnitus. Salicylate-induced hearing loss is believed to arise from a reduction in the electromotile response of outer hair cells (OHCs and/or reduction of KCNQ4 potassium currents in OHCs which decreases the driving force for the transduction current. Therefore, enhancing OHC potassium currents could potentially prevent salicylate-induced temporary hearing loss. In this study, we tested whether opening voltage-gated potassium channels using ICA-105665, a novel small molecule that opens KCNQ2/3 and KCNQ3/5 channels, can reduce salicylate-induced hearing loss. We found that systemic application of ICA-105665 at 10 mg/kg prevented the salicylate-induced amplitude reduction and threshold shift in the compound action potentials recorded at the round window of the cochlea. ICA-105665 also prevented the salicylate-induced reduction of distortion products of otoacoustic emission (DPOAE. These results suggest that ICA-105665 partially compensates for salicylate induced cochlear hearing loss by enhancing KCNQ2/3 and KCNQ3/5 potassium currents and the motility of OHCs.

  17. ``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.

  18. Human hair analysis by PIXE

    International Nuclear Information System (INIS)

    Hair is the unique biological material which, because of its growth, reflects the biomedical and environmental history of the subject. Because of convenience in handling and sampling and relatively high concentrations of metals, trace-element analysis of human hair has been applied widely for different purposes. Although even the measurements of the bulk trace element levels contain some information, the real meaning is contained in longitudinal and radial concentration profiles. This is best achievable by X-ray emission spectroscopy measurements. (author) 98 refs

  19. 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.

  20. Hair loss in cancer chemotherapeutic patients

    Directory of Open Access Journals (Sweden)

    Chadha V

    2003-03-01

    Full Text Available The hair loss in 8 cancer patients aged between 18 and 60 years on chemotherapy was studied. All had diffuce moderate alopecio within 1 month of starting treatment. Of the 8, 3 had only telogen hairs and 3 had high dystrophic hair count. Both anagen and telogen effluvium are implicated.