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ABSTRACT: We characterized side population (SP) cells in the cochlear nucleus (CN). Some genes of stem/progenitor markers in sorted SP cells were identified by microarray analysis and RT-PCR. Furthermore, some cells in the CN also demonstrated self-renewal and clonal expansion activities. These results suggest that tissue stem/ progenitor like cells would be identified and characterized as a slow cycling and immaturity in SP cells of CN.
SP cells were sorted and characterized as regards their activity in the CN in order to identify the tissue progenitor/stem cells in the auditory nervous system.
Bromodeoxyuridine (BrdU)-injected mice were prepared and the long-term BrdU-retaining cells were detected by flow cytometry. Gene expression of SP and MP cells was analyzed by microarray analysis and RT-PCR. SP cells were cultured in conditioned medium to expand stem/progenitor cells in vitro and to estimate the spheroid-forming activity of stem cells.
In all, 1% of cells in the CN were detected as BrdU-positive. SP cells were detected at a frequency of 4.4% and expressed stem/progenitor markers, Abcb1b, Abcg2, Sca1, Notch1, Notch4, Hes1, and Jag1 in microarray analysis. Expression of Abcb1b, Abcg2, Sca1,Oct3/4, and Sox2 as determined by RT-PCR was supported by the microarray data. CN cells also had sphere-forming activity in young mice, but this activity was decreased by aging.
Acta oto-laryngologica 06/2012; 132(7):693-701. · 0.98 Impact Factor
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Yasunori Osumi,
Seiji Bruce Shibata,
Seiji Kanda, Masao Yagi,
Hisashi Ooka,
Takashi Shimano,
Mikiya Asako,
Kohei Kawamoto,
Hiromichi Kuriyama,
Toshiya Inoue,
Toshimasa Nishiyama,
Toshio Yamashita,
Koichi Tomoda
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ABSTRACT: Presbycusis is the impairment of auditory function associated with aging, which stems from peripheral cochlear lesions and degeneration of the central auditory process. The effect of age-induced peripheral hearing loss on the central auditory process is not fully understood. C57Bl/6 (C57) mice present accelerated peripheral hearing loss, which is well developed by middle-age and mimics the human presbycusis pattern. The aim of this study was to elucidate the molecular effects of peripheral hearing loss in the inferior colliculus (IC) with age between young and middle-aged C57 mice using cDNA microarray. Glutamate receptor ionotropic NMDA ζ1 (GluN1) exhibited the greatest decrease in the middle-aged group as determined using cDNA microarray and by further assessment using real-time PCR (qPCR). Histological assessment with in situ hybridization of GluN1 showed significantly decreased expression in all IC subdivisions of the middle-aged group. GluN1 is a receptor for excitatory neurotransmission, and significant downregulation of this gene may be subsequent to the decline of afferent input from the cochlea in aging C57 mice. Consequently, using the combination of microarray, qPCR, and in situ hybridization, we showed that the decline of GluN1 in the IC of aging animals might have a key role in the pathogenesis of presbycusis.
Brain research 03/2012; 1454:23-32. · 2.46 Impact Factor
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ABSTRACT: Systemic air embolism, a very rare clinical condition, has many causes. We report a case of multiple air embolisms following laryngopharyngoesophagectomy salvage surgery for hypopharyngeal residual cancer after concurrent chemoradiotherapy. Cervical infection arose from a fistula caused by postoperative suture failure in which the 56-year-old man suddenly lost consciousness and went into shock. A few days post operation, an air embolism happened and caused in the brain, pulmonary, myocardiac and cerebral infarction. The man died two months after initial occurrence. We suspect that air entered through the ruptured left internal jugular vein via infection due to aspiration at the injury site. Air embolisms are associated with different medical maneuvers, and it is necessary to recognize that they may become a serious perioperative complication.
Nippon Jibiinkoka Gakkai Kaiho 01/2010; 113(1):20-5.
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Nippon Jibiinkoka Gakkai Kaiho 01/2009; 111(12):727-33.
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ABSTRACT: We report results of a retrospective study of 12 cases of adenoid cystic carcinoma (ACC) in the parotid gland. Local pain was often observed in ACC among other malignant parotid tumors. Although fine-needle aspiration cytology (FNA) was not effective for preoperative diagnosis, frozen section diagnosis (FS) during surgery showed excellent results. Cases with T3 or T4 underwent total or enlarged parotidectomy, but, often showed positive surgical margins. Postoperative radiation therapy seemed useful in these cases and the 5-and 10-year disease-specific survivals in these 12 cases were 90.0% and 80.8%. These compare favorably with other reports in the literature. All 12 cases showed NO and no cervical relapse with or without neck dissection, indicating little effectiveness in prophylactic neck dissection. Tumor size, positive surgical margins, and perineural invasion are risk factors for this tumor as mention previously. Patients with perineural invasion, especially preoperative facial nerve palsy (T4a), are more likely to fail than those with two other factors, so, it seems conceivable for cases of T4a to undergo more positive treatment with surgery and postoperative radiation.
Nippon Jibiinkoka Gakkai Kaiho 06/2007; 110(5):410-5.
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ABSTRACT: Antidepressant treatments have been described to induce neurotrophic factors (NTFs) and reverse the cell loss observed in rodent stress models. Amitriptyline (AT), a tricyclic antidepressant agent, has been reported in recent studies to induce glial cell line-derived neurotrophic factor (GDNF) synthesis and release in rat C6 glioblastoma cells. GDNF has shown protection against acoustic trauma in previous studies. Therefore, we investigated whether AT could induce GDNF synthesis in the cochlea and attenuate cochlea damage against acoustic trauma. We used Hartley guinea pigs and injected AT (30 mg/kg) or saline into the peritoneum. Subjects were exposed to 117 dB SPL octave band noise centered at 4 kHz for 24 h. Noise-induced hearing loss (NIHL) was assessed with auditory brain stem response (ABR) at 4, 8 and 16 kHz measured prior to the injection, 3 days and 7 days after noise exposure. For histological assessment, we observed the sensory epithelium using a surface preparation technique and assessed the quantitative hair cell (HC) damage. We evaluated GDNF synthesis with or without intense noise exposure at 3, 12 and 24 h after the administration of AT in the cochlea using Western blot analysis. GDNF expression was shown 3 h and 12 h after the injection without noise, whereas with noise the GDNF expression lasted for 24 h. The AT-administrated group showed significantly reduced ABR threshold shift and less HC damage than the saline-administrated group. These findings suggest that the administration of AT-induced GDNF levels in the cochlea and attenuated cochlea damage from NIHL.
Brain Research 06/2007; 1144:74-81. · 2.73 Impact Factor
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ABSTRACT: The protective effect of dexamethasone (DEX) against noise-induced trauma, as reflected in hair cell destruction and elevation in auditory brainstem response (ABR) sensitivity, was assessed in guinea pigs. The animals were administered DEX (1, 10, 100, and 1000 ng/ml) or artificial perilymph (AP) via a mini-osmotic pump directly into scala tympani and, on the fourth day after pump implantation, exposed to 120 dB SPL octave band noise, centered at 4 kHz, for 24 h. Animals receiving DEX demonstrated a dose-dependent reduction in noise-induced outer hair cell loss (significant at 1, 10 and 100 ng/ml DEX animals compared to AP control animals) and a similar attenuation of the noise-induced ABR threshold shifts, observed 7 days following exposure (significant at 100 ng/ml DEX animals compared to AP control animals). These physiological and morphological results indicate that direct infusion of DEX into the perilymphatic space has protective effects against noise-induced trauma in the guinea pig cochlea.
Hearing Research 11/2004; 196(1-2):58-68. · 2.70 Impact Factor
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ABSTRACT: Brief cochlear excitotoxicity produces temporary neural swelling and transient deficits in auditory sensitivity; however, the consequences of long-lasting excitotoxic insult have not been tested. Chronic intra-cochlear infusion of the glutamate agonist AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) resulted in functional deficits in the sound-evoked auditory brainstem response, as well as in behavioral measures of hearing. The electrophysiological deficits were similar to those observed following acute infusion of AMPA into the cochlea; however, the concentration-response curve was significantly shifted as a consequence of the slower infusion rate used with chronic cochlear administration. As observed following acute excitotoxic insult, complete functional recovery was evident within 7 days of discontinuing the AMPA infusion. Distortion product otoacoustic emissions were not affected by chronic AMPA infusion, suggesting that trauma to outer hair cells did not contribute to AMPA-induced deficits in acoustic sensitivity. Results from the current experiment address the permanence of deficits induced by chronic (14 day) excitotoxic insult as well as deficits in psychophysical detection of longer duration acoustic signals.
The Journal of the Acoustical Society of America 09/2004; 116(2):1044-56. · 1.55 Impact Factor
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ABSTRACT: Glial cell line-derived neurotrophic factor (GDNF) overexpression in the inner ear can protect hair cells against degeneration induced by aminoglycoside ototoxicity. The protective efficiency of GDNF increases when it is combined with co-factors such as transforming growth factor beta1 (TGF-beta1), a ubiquitous cytokine. The aim of this study was to determine whether TGF-beta1 receptors are expressed in the inner ear and whether a cocktail of GDNF and TGF-beta1 transgenes provides enhanced protection of the inner ear against ototoxic trauma. Using RT-PCR analysis, we determined that both TGF-beta1 receptors, type 1 and 2 are present in rat cochlea. We co-inoculated two adenoviral vectors, one encoding human TGF-beta1 gene (Ad.TGF-beta1) and the other encoding human GDNF gene (Ad.GDNF) into guinea pig cochleae 4 days prior to injecting an ototoxic dose of aminoglycosides. Inoculated ears had better hearing and fewer missing inner hair cells after exposure to the aminoglycoside ototoxicity, as compared with controls and ears treated only with Ad.GDNF. Cochleae with TGF-beta1 overexpression exhibited fibrosis in the scala tympani regardless of the presence of GDNF. Our results suggest that the adenovirus-mediated overexpression of GDNF and TGF-beta1 can be used in combination to protect cochlear hair cells and hearing from ototoxic trauma.
Molecular Therapy 05/2003; 7(4):484-92. · 6.87 Impact Factor
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ABSTRACT: This study demonstrates the attenuation of aminoglycoside ototoxicity by cochlear infusion of dexamethasone (Dex) using a microcannulation-osmotic pump delivery system. The results indicate that treating the cochlea with Dex both before and after kanamycin administration was more effective in preventing ototoxicity than Dex treatment only after kanamycin administration. A concentration of 1 ng/ml Dex showed the greatest protective effect on both kanamycin-induced threshold shift of the auditory brainstem response and outer hair cell survival. These results show that the Dex treatment attenuates both functional and structural damage of the inner ear from aminoglycoside toxicity.
Hearing Research 06/2002; 167(1-2):61-70. · 2.70 Impact Factor
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ABSTRACT: Environmental inner ear insults often lead to hair cell injury and loss. Therapeutic measures for the prevention of hair cell loss are currently limited. Several reports have demonstrated the applicability of growth factors for hair cell protection. The goal of the experiments presented here was to assess the protective capability of the human GDNF transgene against noise trauma in the guinea pig cochlea. The left ears of guinea pigs were inoculated with a recombinant adenovirus with a human GDNF insert (Ad.GDNF). Four days later, animals were exposed to noise trauma. One week later, animals were sacrificed and hair cells counted in the left (inoculated) and right (non-inoculated) ears. Auditory brainstem thresholds were measured before the inoculation and just prior to sacrifice. Control groups included inoculation with a reporter gene vector (Ad.lacZ) and Ad.GDNF in normal ears with no noise exposure. The results show that intracochlear inoculation with adenovirus into normal ears does not compromise hair cell counts and ABR thresholds. Both Ad.GDNF and Ad.lacZ vectors can protect the cochlear hair cells and hearing from the noise insult. The difference between the protection afforded by Ad.GDNF and that of the Ad.lacZ vector is not statistically significant. The mechanism of Ad.lacZ protection needs to be elucidated. The data demonstrate the general feasibility of gene therapy for over-expression of neurotrophic factors against noise trauma, and emphasize the complexity of the technique and the problems of variability between subjects.
Noise and Health 02/2001; 3(11):37-47. · 1.25 Impact Factor
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Journal of the Association for Research in Otolaryngology 11/2000; 1(4):315-325. · 2.84 Impact Factor
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ABSTRACT: Delivering and expressing foreign genes can prevent or cure a variety of diseases for which no therapy presently exists. The inner ear is an attractive target for gene therapy for clinical and experimental purposes. Experiments using reporter genes demonstrated the feasibility for gene transfer into cochlear tissues. Herpes simplex virus, adenovirus, adeno-associated virus, and vaccinia virus were used as vectors to deliver these reporter genes. Gene therapy experiments demonstrated protective effects of several growth factors on hair cells and spiral ganglion cells. The transgenes for BDNF, NT-3, and GDNF have been shown to have protective effects in the cochlea when overexpressed via one of these viral vectors. When vector technology allows for inducible and cell-specific gene expression and reduced immune response, gene therapy may become a safe and efficient therapeutic tool in the otology clinic.
(C) 1998 Lippincott Williams & Wilkins, Inc.
Current Opinion in Otolaryngology & Head and Neck Surgery 09/1998; 6(5). · 1.83 Impact Factor
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ABSTRACT: Two possible approaches for cochlear gene transfer have been inoculation via the round window membrane and through a cochleostomy. The aim of this study was to determine which of the two is more effective. Using both approaches, normal-hearing and deafened guinea pigs were inoculated with adenovirus carrying the reporter gene lacZ. After 5 days, the animals were killed and the cochlear tissue was stained with X-gal. The distribution and intensity of staining was estimated by a score system developed to compare gene transfer results between animals. We found that gene transfer via the cochleostomy resulted in a better distribution throughout the cochlea and in higher staining intensity, due to more efficient transfection. Auditory brainstem response (ABR) results showed that neither virus inoculation through a cochleostomy nor through the round window membrane had a significant effect on the click-ABR threshold measured on day 5 following virus injection. Gene transfer via both approaches was also found to be more effective in deafened animals than in hearing animals.
Hearing Research.
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ABSTRACT: Inner ear disease due to hair cell loss is common, and no restorative treatments for the balance and hearing impairment are currently available. To develop clinical means for enhancing protection and regeneration in the inner ear, it is necessary to understand the molecular basis for hereditary and acquired deafness and vestibular disorders. One approach is to identify and characterize genes that regulate protection or repair in other systems. For that purpose, we have used the differential display assay and compared gene expression between normal and acoustically traumatized inner ears of chicks. Several chick cDNAs that were identified are considered as candidates for roles in the reparative process that follows trauma in the basilar papilla. The mammalian vestibular epithelium has a limited regenerative capability. To identify genes that may participate in the regenerative response, we have used gene arrays profiling, comparing normal to drug-traumatized vestibular epithelia. We identified several genes that are differentially expressed in traumatized vestibular epithelium, including several insulin-like growth factor-I binding proteins. To use this molecular knowledge for enhancing protection and repair in the organ of Corti, it is necessary to overexpress the genes of choice in the inner ear. Using viral-mediated gene transfer, we overexpressed transgenic glial cell line-derived neurotrophic factor and demonstrated a robust protective effect against acoustic and ototoxic inner ear trauma. Future identification of the genes that are important for protection and regeneration, along with improved gene transfer technology, will allow the use of gene therapy for treating hereditary and environmental inner ear disease.
Audiology and Neurotology 7(3):161-4. · 2.46 Impact Factor
