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Armstrong PA, Wood SJ, Shimizu N, Kuster K, Perachio A, Makishima T. Preserved otolith organ function in caspase-3-deficient mice with impaired horizontal semicircular canal function. Exp Brain Res 2015; 233:1825-35. [PMID: 25827332 DOI: 10.1007/s00221-015-4254-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 03/10/2015] [Indexed: 11/30/2022]
Abstract
Genetically engineered mice are valuable models for elucidation of auditory and vestibular pathology. Our goal was to establish a comprehensive vestibular function testing system in mice using: (1) horizontal angular vestibulo-ocular reflex (hVOR) to evaluate semicircular canal function and (2) otolith-ocular reflex (OOR) to evaluate otolith organ function and to validate the system by characterizing mice with vestibular dysfunction. We used pseudo off-vertical axis rotation to induce an otolith-only stimulus using a custom-made centrifuge. For the OOR, horizontal slow-phase eye velocity and vertical eye position were evaluated as a function of acceleration. Using this system, we characterized hVOR and OOR in the caspase-3 (Casp3) mutant mice. Casp3 (-/-) mice had severely impaired hVOR gain, while Casp3 (+/-) mice had an intermediate response compared to WT mice. Evaluation of OOR revealed that at low-to-mid frequencies and stimulus intensity, Casp3 mutants and WT mice had similar responses. At higher frequencies and stimulus intensity, the Casp3 mutants displayed mildly reduced otolith organ-related responses. These findings suggest that the Casp3 gene is important for the proper function of the semicircular canals but less important for the otolith organ function.
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Affiliation(s)
- Patrick A Armstrong
- Department of Otolaryngology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX, 77555-0521, USA
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Walther LE, Wenzel A, Buder J, Blödow A, Kniep R. Gentamicin-induced structural damage of human and artificial (biomimetic) otoconia. Acta Otolaryngol 2014; 134:111-7. [PMID: 24215218 DOI: 10.3109/00016489.2013.849384] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSIONS Gentamicin causes irreversible structural damage of human and artificial otoconia by progressive dissolution of calcite. The inner architecture of otoconia is strongly affected by degradation scenarios during gentamicin exposure. Artificial otoconia can be used as a model system mimicking the chemical attacks for detailed investigations. OBJECTIVES To investigate the chemical interactions of gentamicin with natural calcite and human and artificial otoconia under in vivo conditions. METHODS Pure calcite crystals and artificial and human otoconia were exposed to gentamicin injection solutions at various concentrations. Morphological changes were observed in time steps by the use of environmental scanning electron microscopy (ESEM). RESULTS Dissolution of pure calcite crystals results in the formation of well oriented nanoshoots indicating an irreversible chemical reaction with gentamicin. Human and artificial otoconia reveal irreversible structural changes of their surface areas as well as of their inner structure, resulting in characteristic changes at different gentamicin concentrations. Minor changes are first observed by surface alterations and dissolution of calcite in the belly region. Major changes result in further reduction of the belly area reaching the center of symmetry. Finally, a complete dissolution of the branches takes place. Artificial otoconia provide detailed insight into surface alterations.
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Affiliation(s)
- Leif Erik Walther
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medicine Mannheim, University of Heidelberg , Mannheim , Germany
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Fridman GY, Davidovics NS, Dai C, Migliaccio AA, Della Santina CC. Vestibulo-ocular reflex responses to a multichannel vestibular prosthesis incorporating a 3D coordinate transformation for correction of misalignment. J Assoc Res Otolaryngol 2010; 11:367-81. [PMID: 20177732 PMCID: PMC2914246 DOI: 10.1007/s10162-010-0208-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 01/17/2010] [Indexed: 10/19/2022] Open
Abstract
There is no effective treatment available for individuals unable to compensate for bilateral profound loss of vestibular sensation, which causes chronic disequilibrium and blurs vision by disrupting vestibulo-ocular reflexes that normally stabilize the eyes during head movement. Previous work suggests that a multichannel vestibular prosthesis can emulate normal semicircular canals by electrically stimulating vestibular nerve branches to encode head movements detected by mutually orthogonal gyroscopes affixed to the skull. Until now, that approach has been limited by current spread resulting in distortion of the vestibular nerve activation pattern and consequent inability to accurately encode head movements throughout the full 3-dimensional (3D) range normally transduced by the labyrinths. We report that the electrically evoked 3D angular vestibulo-ocular reflex exhibits vector superposition and linearity to a sufficient degree that a multichannel vestibular prosthesis incorporating a precompensatory 3D coordinate transformation to correct misalignment can accurately emulate semicircular canals for head rotations throughout the range of 3D axes normally transduced by a healthy labyrinth.
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Affiliation(s)
- Gene Y. Fridman
- Vestibular NeuroEngineering Laboratory, Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Ross Bldg Rm 830, 720 Rutland Ave., Baltimore, 11 MD 21205 USA
| | - Natan S. Davidovics
- Vestibular NeuroEngineering Laboratory, Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Ross Bldg Rm 830, 720 Rutland Ave., Baltimore, 11 MD 21205 USA
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Chenkai Dai
- Vestibular NeuroEngineering Laboratory, Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Ross Bldg Rm 830, 720 Rutland Ave., Baltimore, 11 MD 21205 USA
| | - Americo A. Migliaccio
- Vestibular NeuroEngineering Laboratory, Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Ross Bldg Rm 830, 720 Rutland Ave., Baltimore, 11 MD 21205 USA
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Charles C. Della Santina
- Vestibular NeuroEngineering Laboratory, Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Ross Bldg Rm 830, 720 Rutland Ave., Baltimore, 11 MD 21205 USA
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
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Shanidze N, Kim AH, Raphael Y, King WM. Eye-head coordination in the guinea pig I. Responses to passive whole-body rotations. Exp Brain Res 2010; 205:395-404. [PMID: 20686891 DOI: 10.1007/s00221-010-2374-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 07/15/2010] [Indexed: 11/28/2022]
Abstract
Vestibular reflexes act to stabilize the head and eyes in space during locomotion. Head stability is essential for postural control, whereas retinal image stability enhances visual acuity and may be essential for an animal to distinguish self-motion from that of an object in the environment. Guinea pig eye and head movements were measured during passive whole-body rotation in order to assess the efficacy of vestibular reflexes. The vestibulo-ocular reflex (VOR) produced compensatory eye movements with a latency of approximately 7 ms that compensated for 46% of head movement in the dark and only slightly more in the light (54%). Head movements, in response to abrupt body rotations, also contributed to retinal stability (21% in the dark; 25% in the light) but exhibited significant variability. Although compensatory eye velocity produced by the VOR was well correlated with head-in-space velocity, compensatory head-on-body speed and direction were variable and poorly correlated with body speed. The compensatory head movements appeared to be determined by passive biomechanical (e.g., inertial effects, initial tonus) and active mechanisms (the vestibulo-collic reflex or VCR). Chemically induced, bilateral lesions of the peripheral vestibular system abolished both compensatory head and eye movement responses.
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Affiliation(s)
- N Shanidze
- Department of Otolaryngology, University of Michigan, Ann Arbor, MI, USA.
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Della Santina CC, Migliaccio AA, Patel AH. A multichannel semicircular canal neural prosthesis using electrical stimulation to restore 3-d vestibular sensation. IEEE Trans Biomed Eng 2007; 54:1016-30. [PMID: 17554821 PMCID: PMC2767274 DOI: 10.1109/tbme.2007.894629] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Bilateral loss of vestibular sensation can be disabling. Those afflicted suffer illusory visual field movement during head movements, chronic disequilibrium and postural instability due to failure of vestibulo-ocular and vestibulo-spinal reflexes. A neural prosthesis that emulates the normal transduction of head rotation by semicircular canals could significantly improve quality of life for these patients. Like the three semicircular canals in a normal ear, such a device should at least transduce three orthogonal (or linearly separable) components of head rotation into activity on corresponding ampullary branches of the vestibular nerve. We describe the design, circuit performance and in vivo application of a head-mounted, semi-implantable multichannel vestibular prosthesis that encodes head movement in three dimensions as pulse-frequency-modulated electrical stimulation of three or more ampullary nerves. In chinchillas treated with intratympanic gentamicin to ablate vestibular sensation bilaterally, prosthetic stimuli elicited a partly compensatory angular vestibulo-ocular reflex in multiple planes. Minimizing misalignment between the axis of eye and head rotation, apparently caused by current spread beyond each electrode's targeted nerve branch, emerged as a key challenge. Increasing stimulation selectivity via improvements in electrode design, surgical technique and stimulus protocol will likely be required to restore AVOR function over the full range of normal behavior.
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Affiliation(s)
- Charles C Della Santina
- Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins School of Medicine, 601 North Caroline Street, Baltimore, MD 21287, USA.
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Maruta J, Simpson JI, Raphan T, Cohen B. Orienting eye movements and nystagmus produced by translation while rotating (TWR). Exp Brain Res 2005; 163:273-83. [PMID: 15702320 DOI: 10.1007/s00221-004-2178-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Accepted: 10/14/2004] [Indexed: 10/25/2022]
Abstract
Sinusoidal translation while rotating at constant angular velocity about a vertical axis (translation while rotating, TWR) produces centripetal and translational accelerations along the direction of translation and an orthogonal Coriolis acceleration due to the translation in the rotating frame. Thus, a Coriolis acceleration is produced along the bitemporal axis when oscillating along the naso-occipital axis, and along the naso-occipital axis when oscillating along the bitemporal axis. Together, these components generate an elliptically rotating acceleration vector that revolves around the head in the direction of rotation at the frequency of oscillation. Here we studied the orienting and compensatory responses of rabbits during TWR. Combinations of centripetal and translational accelerations were held constant at 0.5 g, and oscillation frequencies were varied from 0.01-0.33 Hz. The amplitude of the Coriolis acceleration increased with the frequency of translation. Naso-occipital translation caused vergence and pitch at all frequencies and roll at higher frequencies, and bitemporal translation produced roll at all frequencies and vergence and pitch at higher frequencies. The sensitivity of each ocular orienting component to linear acceleration was comparable across the different oscillation frequencies. TWR also induced continuous yaw nystagmus with slow phase velocity in the direction of rotation of the acceleration vector. Thresholds for appearance of nystagmus were 0.05 Hz, corresponding to a Coriolis acceleration of 0.06 g. Mean slow phase velocity for a rotating linear acceleration vector produced by 0.5 g along the translation axis and 0.34 g of Coriolis acceleration along the orthogonal axis were approximately 9 degrees /s. Eye velocities during TWR were similar to those generated by off-vertical axis rotation (OVAR), but were opposite in direction with regard to head rotation, following the direction of the rotating acceleration vector in both paradigms. Both are produced by activation of velocity storage in the vestibular system. One important difference between TWR and OVAR is that the head is always upright with regard to gravity during TWR. We speculate that the brain may use these low amplitude rotating linear accelerations to generate eye velocities that help to orient gaze when making turns during normal locomotion.
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Affiliation(s)
- Jun Maruta
- Department of Neurology and Physiology and Biophysics, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, USA
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Billig I, Balaban CD. Zonal organization of the vestibulo-cerebellar pathways controlling the horizontal eye muscles using two recombinant strains of pseudorabies virus. Neuroscience 2005; 133:1047-59. [PMID: 15923089 DOI: 10.1016/j.neuroscience.2005.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2004] [Revised: 03/22/2005] [Accepted: 04/01/2005] [Indexed: 11/29/2022]
Abstract
Many studies have documented the influence of the flocculus upon vestibulo-ocular reflex eye movements. Electrical stimulation of Purkinje cells in a central longitudinal zone evoked slow ipsilateral eye movements in the horizontal plane. Recently, the organization of neurons in the vestibulo-cerebellar pathways controlling single lateral rectus and medial rectus muscles was identified in rats using the transynaptic transport of pseudorabies virus. Overlapping distributions of neurons innervating single muscles were located predominantly in a central longitudinal zone of ventral paraflocculi/dorsal flocculi, and the rostral half of ventral flocculi. This study used two isogenic pseudorabies virus recombinants to determine whether individual cells in those brain regions have collateralized projections to motoneuron pools innervating the right lateral rectus and the left medial rectus muscles using different survival times and dual injection paradigms. The infected neurons were detected using dual-labeling immunofluorescence. Three populations of labeled neurons were observed: two populations replicated only one reporter while a third contained both viruses (i.e. dual-labeled). Most dual-labeled cells were located in a central longitudinal zone of the ventral paraflocculus, ipsilateral to the injection into the medial rectus, whereas very few were in the flocculus. This finding suggests that the flocculus and ventral paraflocculus may exert influence upon distinct vestibulo-cerebellar pathways. Most Purkinje cells in the ventral paraflocculus may influence the vestibulo-ocular reflex pathways through collateralization, whereas those in the flocculus may instead provide a monocular control of eye movements.
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Affiliation(s)
- I Billig
- Department of Otolaryngology, Eye and Ear Institute, Room 106A, 203 Lothrop Street, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Bánfi B, Malgrange B, Knisz J, Steger K, Dubois-Dauphin M, Krause KH. NOX3, a superoxide-generating NADPH oxidase of the inner ear. J Biol Chem 2004; 279:46065-72. [PMID: 15326186 DOI: 10.1074/jbc.m403046200] [Citation(s) in RCA: 321] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Reactive oxygen species (ROS) play a major role in drug-, noise-, and age-dependent hearing loss, but the source of ROS in the inner ear remains largely unknown. Herein, we demonstrate that NADPH oxidase (NOX) 3, a member of the NOX/dual domain oxidase family of NADPH oxidases, is highly expressed in specific portions of the inner ear. As assessed by real-time PCR, NOX3 mRNA expression in the inner ear is at least 50-fold higher than in any other tissues where its expression has been observed (e.g. fetal kidney, brain, skull). Microdissection and in situ hybridization studies demonstrated that NOX3 is localized to the vestibular and cochlear sensory epithelia and to the spiral ganglions. Transfection of human embryonic kidney 293 cells with NOX3 revealed that it generates low levels of ROS on its own but produces high levels of ROS upon co-expression with cytoplasmic NOX subunits. NOX3-dependent superoxide production required a stimulus in the absence of subunits and upon co-expression with phagocyte NADPH oxidase subunits p47(phox) and p67(phox), but it was stimulus-independent upon co-expression with colon NADPH oxidase subunits NOX organizer 1 and NOX activator 1. Pre-incubation of NOX3-transfected human embryonic kidney 293 cells with the ototoxic drug cisplatin markedly enhanced superoxide production, in both the presence and the absence of subunits. Our data suggest that NOX3 is a relevant source of ROS generation in the cochlear and vestibular systems and that NOX3-dependent ROS generation might contribute to hearing loss and balance problems in response to ototoxic drugs.
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Affiliation(s)
- Botond Bánfi
- Department of Anatomy and Cell Biology and Inflammation Program and Dept. of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
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