Analysis Tools
hearing/vestibular/ear
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• in the second row of inner hair cells at P8 but not P4, the prolate tips are frequently exaggerated and over-elongated and are filled with actin filaments
• deterioration of the staircase architecture of the inner hair cell bundle from P6 onwards
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• in cochlea from P32 onwards, the mechanotransducing stereocilia in the second row are reduced in height and the third stereocilia row is almost completely reabsorbed
• however, stereocilia elongate normally in hair cells
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• reduction in second row stereocilia widths between P8 and P11 in inner hair cells
• however, stereocilia thinning is specific to inner hair cells as the shorter row stereocilia in outer hair cells retract without changes in diameter
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• stereocilia bundles of inner and outer hair cells are normal at P4 but subsequently degenerate
• degeneration is specific to the shorter rows that harbor active MET channels and does not affect the tallest rows, at least up until P50
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• maximal mechanoelectrical transduction current amplitudes are not different, however responses to small bundle deflections (150-300 nm) are larger in mutant inner hair cells, indicating an increased deflection sensitivity of the transduction apparatus
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• around the onset of hearing at 2 weeks, mice respond to loud sounds of 75 dB of sound pressure level at 20 kHz, but by 4-6 weeks of age, auditory brainstem response thresholds at 20 kHz exceed 100 dB sound pressure level, indicating a rapid progression to profound deafness
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• mice exhibit a complete absence of distortion product otoacoustic emissions at 2 and 6 weeks of age, indicating that cochlear amplification is disrupted
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• mice are deaf at all frequencies tested at 6 weeks of age
• however, mice lack circling behavior and perform normally in swimming tests, indicating normal vestibular function
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nervous system
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• in the second row of inner hair cells at P8 but not P4, the prolate tips are frequently exaggerated and over-elongated and are filled with actin filaments
• deterioration of the staircase architecture of the inner hair cell bundle from P6 onwards
|
|
• in cochlea from P32 onwards, the mechanotransducing stereocilia in the second row are reduced in height and the third stereocilia row is almost completely reabsorbed
• however, stereocilia elongate normally in hair cells
|
|
• reduction in second row stereocilia widths between P8 and P11 in inner hair cells
• however, stereocilia thinning is specific to inner hair cells as the shorter row stereocilia in outer hair cells retract without changes in diameter
|
|
• stereocilia bundles of inner and outer hair cells are normal at P4 but subsequently degenerate
• degeneration is specific to the shorter rows that harbor active MET channels and does not affect the tallest rows, at least up until P50
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• maximal mechanoelectrical transduction current amplitudes are not different, however responses to small bundle deflections (150-300 nm) are larger in mutant inner hair cells, indicating an increased deflection sensitivity of the transduction apparatus
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Mouse Models of Human Disease |
DO ID | OMIM ID(s) | Ref(s) | |
| autosomal recessive nonsyndromic deafness 3 | DOID:0110488 |
OMIM:600316 |
J:226820 | |
