Analysis Tools
growth/size/body
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• mutants are identifiable at 2 weeks of age by their reduced body size
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behavior/neurological
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• at P25 mice fail to show a startle response
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head tossing
(
J:111661
)
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• at P25 mutants display distinct head tossing
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• mutants are identifiable at 2 weeks of age by their unstable gait
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• at P25 mutants display bi-directional circling behavior; mutants display circling behavior as early as P10-14 and persists through life
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nervous system
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• some mutants have normal appearing stereocilia while some display scattered outer hair cells with visible alterations in the arrangement of the stereocilia; the most severely affected mutants have essentially all abnormal outer hair cell bundle
• cuticular plates show various surface irregularities including localized swelling in areas where stereocillia are missing
• irregular patterns of insertion of stereocilia rootlets into OHC cuticular plates are seen; stereocilia rootlets do not run in parallel through the cuticular plate
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• many outer hair cells have hair bundles that are abnormal and rotated out of normal position at the apex of the cell
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• at P10, loss of OHC stereocilia within individual bundles can be observed
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• loss of inner hair cells is observed throughout the cochlea
• at P40 mutants show complete loss of hair cells with severe inner hair cell loss affecting all cochlear turns
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• loss of outer hair cells is observed throughout the cochlea
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• at P40 there are reduced numbers of spiral ganglion cells in the most severely affected areas
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hearing/vestibular/ear
| N |
• cochlear duct retains normal configuration in mutants; Reissner's membrane and stria vascularis appear normal
|
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• scattered focal lesions where supporting cells and sensory cells are lost leading to collapse of the neuroepithelium are seen at P20
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• some mutants have normal appearing stereocilia while some display scattered outer hair cells with visible alterations in the arrangement of the stereocilia; the most severely affected mutants have essentially all abnormal outer hair cell bundle
• cuticular plates show various surface irregularities including localized swelling in areas where stereocillia are missing
• irregular patterns of insertion of stereocilia rootlets into OHC cuticular plates are seen; stereocilia rootlets do not run in parallel through the cuticular plate
|
|
• many outer hair cells have hair bundles that are abnormal and rotated out of normal position at the apex of the cell
|
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• at P10, loss of OHC stereocilia within individual bundles can be observed
|
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• loss of inner hair cells is observed throughout the cochlea
• at P40 mutants show complete loss of hair cells with severe inner hair cell loss affecting all cochlear turns
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• loss of outer hair cells is observed throughout the cochlea
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• degenerative changes are seen at P20
• at P40 there are patchy areas throughout the length of the cochlea where the organ of Corti is completely collapsed
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• mutants tested at P21 show no auditory brainstem response at any intensity of sound
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