Aki Inoue - Academia.edu (original) (raw)
Papers by Aki Inoue
Annals of the New York Academy of Sciences, 2009
Cell and Tissue Research, 2014
We examine developmental changes in the responsiveness of rat vestibular ganglion neurons (VGNs) ... more We examine developmental changes in the responsiveness of rat vestibular ganglion neurons (VGNs) to two neurotrophic factors (NTFs), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and investigate the protective effects of these NTFs against ototoxic drugs during postnatal development in dissociated cultures. VGNs were obtained from rats on postnatal days (P) 1, 3, 7 and 14. BDNF facilitated neuronal survival as well as neurite sprouting of VGNs obtained from younger rats (P1 and P3), whereas these effects were not observed in older rats (P7 and P14). BDNF was also effective in facilitating neurite extension in VGNs at each of the postnatal ages. NT-3 also facilitated neuronal survival and neurite extension of VGNs from younger rats but these effects were significantly smaller than those of BDNF (p < 0.05). The protective effects of BDNF and NT-3 against ototoxic drugs, gentamicin and cisplatin, were also age-dependent: they were effective for neuronal survival, neurite sprouting and neurite extension in VGNs from younger rats, whereas these effects tended to disappear in VGNs from older rats. Analysis of the changes in the expression of the receptors of NTFs revealed that expression of TrkB and TrkC proteins and their mRNA did not change during the developmental period, whereas expression of p75(NTR) protein was down-regulated together with that of p75(NTR) mRNA during the developmental period. Developmental changes in the responsiveness to exogenous NTFs in VGNs, which is not caused by the changes of their receptors but probably caused by changes in the intracellular signaling pathways, should be taken into consideration in the prevention of neuronal degeneration caused by ototoxic drugs.
Brain Research, 2012
The primary afferent neurons of the vestibular ganglion convey sensory information from hair cell... more The primary afferent neurons of the vestibular ganglion convey sensory information from hair cells in the semicircular canals and otolith organs to the vestibular nuclei, the adjacent brainstem and the cerebellum. The intrinsic firing properties of vestibular ganglion cells (VGCs) are heterogeneous and have been classified into phasic, intermediate and tonic firing types on the basis of their response to injected depolarizing currents. A previous study from our group showed that the proportion of phasic discharging VGCs decreased during the first postnatal weeks. Moreover, α-dendrotoxin (α-DTX), a Kv1 potassium channels antagonist, turned neuron phasic firing to tonic, thus suggesting that these channels play an important role in the developmental changes of VGCs firing patterns. Here, by using immunohistochemistry, Western blotting and quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR), we explored the change in the expression of α-DTX-sensitive K + channels, Kv1.1, Kv1.2 and Kv1.6 in rat VGCs during early postnatal periods. We showed that expression of Kv1.6 protein is down-regulated together with expression of Kv1.6 mRNA after postnatal day 7 in rat VGCs whereas expression of Kv1.1 and Kv1.2 proteins did not change during the same developmental period. Our results suggest that down-regulation of the Kv1.6 protein and mRNA may be associated with maturation of excitable properties of primary vestibular neurons.
Auris Nasus Larynx, 2010
We rarely encounter patients with proptosis, however, it is known that inflammation and extension... more We rarely encounter patients with proptosis, however, it is known that inflammation and extension of paranasal sinus tumors may cause this condition. We should consider the diseases that may cause proptosis to facilitate the diagnosis. Recently, we treated proptosis in 2 cases, one with inflammatory myofibroblastic tumor (IMT) and the other with malignant lymphoma. As these 2 diseases show various clinical features and these features frequently overlap, it is difficult to differentiate between IMT and malignant lymphoma without pathological examinations. In this study, we review the relevant literature reports and discuss the difficulties in establishing a clinicopathological diagnosis and present a slight distinction in magnetic resonance imaging. #
Audiology and Neurotology, 2013
Multifrequency tympanometry (MFT) is the measurement of the impedance of the middle ear transmiss... more Multifrequency tympanometry (MFT) is the measurement of the impedance of the middle ear transmission system at a wide range of frequencies from 200 Hz to 2 kHz. A potential use of MFT as a new diagnostic tool for detecting endolymphatic hydrops has recently been reported. However, its clinical usefulness for diagnosing Ménière's disease (MD) remains unclear. To evaluate the clinical usefulness of MFT as a new qualitative and diagnostic test for MD, we performed MFT in 70 patients with unilateral or bilateral MD and in 29 normal control subjects. The width of double peaks in the admittance tympanograms (Y width) at 2 kHz and the resonance frequency (RF) were analyzed, and receiver operating characteristic (ROC) curves were constructed. The Y width in MD-affected ears was significantly greater than that in control ears (p < 0.001). The RF in MD-affected ears was significantly lower than that in control ears (p < 0.01). Neither the Y width nor RF had a significant relationship with hearing levels or the results of caloric and vestibular myogenic potential testings. The area under the ROC curve was 0.71 for the Y width and 0.66 for the RF. At the optimal cutoff points, the sensitivity and specificity of the Y width were 47.3 and 86.8%, respectively, and those of the RF were 41.3 and 84.2%, respectively. These results indicated that MFT is significantly associated with the presence of MD, but its diagnostic accuracy is only modest. MFT is a simple, noninvasive test, which should be considered as a complementary test in the diagnosis of MD.
Acta Oto-laryngologica, 2007
Multiple system atrophy (MSA) is a progressive neurodegenerative disease that is characterized by... more Multiple system atrophy (MSA) is a progressive neurodegenerative disease that is characterized by varying degrees of parkinsonism and cerebellar, corticospinal, and autonomic dysfunction. Vocal cord abductor paralysis (VCAP) is considered a sign of a poor prognosis in MSA, because it is a life-threatening complication that may cause nocturnal sudden death. This case report presents a patient who was treated for Parkinson's disease, and complained of dizziness and sleep apnea. We examined VCAP using fiberoptic laryngoscopy as the possible cause of sleep apnea. VCAP usually occurs in the advanced stages of MSA and is accompanied by a worsening of other symptoms. Optokinetic nystagmus was severely impaired and the caloric test response was bilaterally absent. Objective findings such as VCAP and abnormal neuro-otological results led to the diagnosis of MSA.
Acta Oto-laryngologica, 2012
Inferior vestibular neuritis (IVN) is a relatively minor subtype of vestibular neuritis (VN) and ... more Inferior vestibular neuritis (IVN) is a relatively minor subtype of vestibular neuritis (VN) and its clinical characteristics are unique. To clarify clinical characteristics of IVN in comparison with conventional VN. This was a retrospective case series review. Caloric responses and cervical vestibular evoked myogenic potential (cVEMP) responses were measured in 71 patients with VN. The patients were classified into three groups: (1) IVN group, who showed only asymmetrical cVEMP responses; (2) superior VN (SVN) group, who showed only asymmetrical caloric responses; (3) total VN (TVN) group, who showed asymmetrical responses in both tests. The clinical records of time course of subjective symptoms (duration of attack, duration of hospitalization, and time to remission) were reviewed and other profiles (age, sex, affected side, acute symptoms, and sequelae) were evaluated. Of the 71 patients with VN, 13 (18%) were classified as having IVN. The mean age and time to remission of patients with IVN (44.2 ± 4.8 years, 0.9 ± 0.5 months) were significantly lower and shorter, respectively, than those of patients with TVN (57.3 ± 2.5 years, 4.9 ± 4.7 months). There were no significant differences in other symptoms and profiles among the three groups. No patients with IVN showed benign paroxysmal positional vertigo as a sequela.
Audiology and Neurotology, 2013
Annals of the New York Academy of Sciences, 2009
Cell and Tissue Research, 2014
We examine developmental changes in the responsiveness of rat vestibular ganglion neurons (VGNs) ... more We examine developmental changes in the responsiveness of rat vestibular ganglion neurons (VGNs) to two neurotrophic factors (NTFs), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and investigate the protective effects of these NTFs against ototoxic drugs during postnatal development in dissociated cultures. VGNs were obtained from rats on postnatal days (P) 1, 3, 7 and 14. BDNF facilitated neuronal survival as well as neurite sprouting of VGNs obtained from younger rats (P1 and P3), whereas these effects were not observed in older rats (P7 and P14). BDNF was also effective in facilitating neurite extension in VGNs at each of the postnatal ages. NT-3 also facilitated neuronal survival and neurite extension of VGNs from younger rats but these effects were significantly smaller than those of BDNF (p < 0.05). The protective effects of BDNF and NT-3 against ototoxic drugs, gentamicin and cisplatin, were also age-dependent: they were effective for neuronal survival, neurite sprouting and neurite extension in VGNs from younger rats, whereas these effects tended to disappear in VGNs from older rats. Analysis of the changes in the expression of the receptors of NTFs revealed that expression of TrkB and TrkC proteins and their mRNA did not change during the developmental period, whereas expression of p75(NTR) protein was down-regulated together with that of p75(NTR) mRNA during the developmental period. Developmental changes in the responsiveness to exogenous NTFs in VGNs, which is not caused by the changes of their receptors but probably caused by changes in the intracellular signaling pathways, should be taken into consideration in the prevention of neuronal degeneration caused by ototoxic drugs.
Brain Research, 2012
The primary afferent neurons of the vestibular ganglion convey sensory information from hair cell... more The primary afferent neurons of the vestibular ganglion convey sensory information from hair cells in the semicircular canals and otolith organs to the vestibular nuclei, the adjacent brainstem and the cerebellum. The intrinsic firing properties of vestibular ganglion cells (VGCs) are heterogeneous and have been classified into phasic, intermediate and tonic firing types on the basis of their response to injected depolarizing currents. A previous study from our group showed that the proportion of phasic discharging VGCs decreased during the first postnatal weeks. Moreover, α-dendrotoxin (α-DTX), a Kv1 potassium channels antagonist, turned neuron phasic firing to tonic, thus suggesting that these channels play an important role in the developmental changes of VGCs firing patterns. Here, by using immunohistochemistry, Western blotting and quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR), we explored the change in the expression of α-DTX-sensitive K + channels, Kv1.1, Kv1.2 and Kv1.6 in rat VGCs during early postnatal periods. We showed that expression of Kv1.6 protein is down-regulated together with expression of Kv1.6 mRNA after postnatal day 7 in rat VGCs whereas expression of Kv1.1 and Kv1.2 proteins did not change during the same developmental period. Our results suggest that down-regulation of the Kv1.6 protein and mRNA may be associated with maturation of excitable properties of primary vestibular neurons.
Auris Nasus Larynx, 2010
We rarely encounter patients with proptosis, however, it is known that inflammation and extension... more We rarely encounter patients with proptosis, however, it is known that inflammation and extension of paranasal sinus tumors may cause this condition. We should consider the diseases that may cause proptosis to facilitate the diagnosis. Recently, we treated proptosis in 2 cases, one with inflammatory myofibroblastic tumor (IMT) and the other with malignant lymphoma. As these 2 diseases show various clinical features and these features frequently overlap, it is difficult to differentiate between IMT and malignant lymphoma without pathological examinations. In this study, we review the relevant literature reports and discuss the difficulties in establishing a clinicopathological diagnosis and present a slight distinction in magnetic resonance imaging. #
Audiology and Neurotology, 2013
Multifrequency tympanometry (MFT) is the measurement of the impedance of the middle ear transmiss... more Multifrequency tympanometry (MFT) is the measurement of the impedance of the middle ear transmission system at a wide range of frequencies from 200 Hz to 2 kHz. A potential use of MFT as a new diagnostic tool for detecting endolymphatic hydrops has recently been reported. However, its clinical usefulness for diagnosing Ménière's disease (MD) remains unclear. To evaluate the clinical usefulness of MFT as a new qualitative and diagnostic test for MD, we performed MFT in 70 patients with unilateral or bilateral MD and in 29 normal control subjects. The width of double peaks in the admittance tympanograms (Y width) at 2 kHz and the resonance frequency (RF) were analyzed, and receiver operating characteristic (ROC) curves were constructed. The Y width in MD-affected ears was significantly greater than that in control ears (p < 0.001). The RF in MD-affected ears was significantly lower than that in control ears (p < 0.01). Neither the Y width nor RF had a significant relationship with hearing levels or the results of caloric and vestibular myogenic potential testings. The area under the ROC curve was 0.71 for the Y width and 0.66 for the RF. At the optimal cutoff points, the sensitivity and specificity of the Y width were 47.3 and 86.8%, respectively, and those of the RF were 41.3 and 84.2%, respectively. These results indicated that MFT is significantly associated with the presence of MD, but its diagnostic accuracy is only modest. MFT is a simple, noninvasive test, which should be considered as a complementary test in the diagnosis of MD.
Acta Oto-laryngologica, 2007
Multiple system atrophy (MSA) is a progressive neurodegenerative disease that is characterized by... more Multiple system atrophy (MSA) is a progressive neurodegenerative disease that is characterized by varying degrees of parkinsonism and cerebellar, corticospinal, and autonomic dysfunction. Vocal cord abductor paralysis (VCAP) is considered a sign of a poor prognosis in MSA, because it is a life-threatening complication that may cause nocturnal sudden death. This case report presents a patient who was treated for Parkinson's disease, and complained of dizziness and sleep apnea. We examined VCAP using fiberoptic laryngoscopy as the possible cause of sleep apnea. VCAP usually occurs in the advanced stages of MSA and is accompanied by a worsening of other symptoms. Optokinetic nystagmus was severely impaired and the caloric test response was bilaterally absent. Objective findings such as VCAP and abnormal neuro-otological results led to the diagnosis of MSA.
Acta Oto-laryngologica, 2012
Inferior vestibular neuritis (IVN) is a relatively minor subtype of vestibular neuritis (VN) and ... more Inferior vestibular neuritis (IVN) is a relatively minor subtype of vestibular neuritis (VN) and its clinical characteristics are unique. To clarify clinical characteristics of IVN in comparison with conventional VN. This was a retrospective case series review. Caloric responses and cervical vestibular evoked myogenic potential (cVEMP) responses were measured in 71 patients with VN. The patients were classified into three groups: (1) IVN group, who showed only asymmetrical cVEMP responses; (2) superior VN (SVN) group, who showed only asymmetrical caloric responses; (3) total VN (TVN) group, who showed asymmetrical responses in both tests. The clinical records of time course of subjective symptoms (duration of attack, duration of hospitalization, and time to remission) were reviewed and other profiles (age, sex, affected side, acute symptoms, and sequelae) were evaluated. Of the 71 patients with VN, 13 (18%) were classified as having IVN. The mean age and time to remission of patients with IVN (44.2 ± 4.8 years, 0.9 ± 0.5 months) were significantly lower and shorter, respectively, than those of patients with TVN (57.3 ± 2.5 years, 4.9 ± 4.7 months). There were no significant differences in other symptoms and profiles among the three groups. No patients with IVN showed benign paroxysmal positional vertigo as a sequela.
Audiology and Neurotology, 2013