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2.
Sci Rep ; 9(1): 1743, 2019 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-30742012

RESUMO

We designed a prospective study to evaluate changes in tinnitus after vestibular schwannoma (VS) surgery. Subjects included 41 patients who were diagnosed with a VS and underwent translabyrinthine microsurgery (TLM) between January 2015 and May 2016. All patients underwent related examinations and were asked to answer the Tinnitus Handicap Inventory (THI) scale and a visual analog scale (VAS) of tinnitus severity both pre- and postoperatively. Of the 41 patients, 31 (75.6%) suffered from tinnitus before surgery. Microsurgery was associated with an overall decrease in tinnitus (p < 0.001). There was a significant improvement in THI and VAS scores after surgery (p = 0.001 and p = 0.005, respectively). The decrease in THI scores in the low-frequency group was significantly larger than that of the mid- and high-frequency groups after surgery (p = 0.034 and p = 0.001, respectively). The loudness of tinnitus decreased significantly after surgery (p = 0.031). Tinnitus in patients with VS improved after TLM. Patients with mid-/high-frequency tinnitus and louder tinnitus preoperatively seemed to have a worse prognosis than those with low-frequency and quieter tinnitus.

4.
J Neurosci Res ; 90(11): 2201-13, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22847875

RESUMO

Bilirubin can cause temporary or permanent sensorineural deafness in newborn babies with hyperbilirubinemia. However, the underlying targets and physiological effects of bilirubin-induced damage in the peripheral auditory system are unclear. Using cochlear functional assays and electron microscopy imaging of the inner ear in neonatal guinea pigs, we show here that bilirubin exposure resulted in threshold elevation in both compound action potential (CAP) and auditory brainstem response (ABR), which was apparent at 1 hr and peaked 8 hr after drug administration. The threshold elevation was associated with delayed wave latencies and elongated interwave intervals in ABR and CAP. At 72 hr postinjection, these measures returned to control levels, except for the CAP amplitude. Cochlear microphonics remained unchanged during the experiment. Morphological abnormalities were consistent with the electrophysiological dysfunction, revealing fewer auditory nerve fibers (ANFs) in the basal turn, myelin sheath lesions of spiral ganglion neurons (SGNs) and ANFs, and loss of type 1 afferent endings beneath inner hair cells (IHCs) without loss of hair cells at 8 hr posttreatment. Similar to the electrophysiological findings, morphological changes were mostly reversed 10 days after treatment, except for the ANF reduction in the basal turn. These results suggest that hyperbilirubinemia in neonatal guinea pigs impaired auditory peripheral neuromechanisms that targeted mainly the IHC synapses and the myelin sheath of SGNs and their fibers. Our observations indicate a potential connection between hyperbilirubinemia and auditory neuropathy.


Assuntos
Nervo Coclear/ultraestrutura , Perda Auditiva Central/etiologia , Perda Auditiva Central/patologia , Hiperbilirrubinemia/complicações , Gânglio Espiral da Cóclea/ultraestrutura , Potenciais de Ação/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Bilirrubina/toxicidade , Nervo Coclear/efeitos dos fármacos , Modelos Animais de Doenças , Potenciais Evocados Auditivos do Tronco Encefálico/efeitos dos fármacos , Feminino , Cobaias , Masculino , Microscopia Eletrônica de Transmissão , Gânglio Espiral da Cóclea/efeitos dos fármacos
5.
Brain Res ; 1348: 30-41, 2010 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-20561511

RESUMO

Previous studies have suggested that bilirubin can potentiate GABA/glycinergic synaptic transmission in lateral superior olivary nucleus neurons, but the cellular mechanism has not been defined. The present study evaluated the possible roles of protein kinase A (PKA) and C (PKC) in bilirubin potentiation of GABA/glycinergic synaptic transmission in rat ventral cochlear nucleus (VCN) neurons. VCN neurons were acutely isolated from postnatal 10-12-day-old (P10-12) rats and were voltage-clamped in whole-cell mode. Miniature inhibitory postsynaptic currents (mIPSC) frequencies, but not amplitude, were increased by bilirubin. Forskolin (PKA activator) and H-89 (PKA inhibitor) also individually increased mIPSCs frequency, with an additional increase induced by co-incubation with bilirubin and H-89. Pretreatment with forskolin blocked bilirubin potentiation. mIPSC frequency was not altered by phorbol 12,13-diacetate (PKC activator), but mIPSC frequency was increased following co-application of bilirubin. The mIPSC frequency was increased by chelerythrine (PKC inhibitor), and then further increased after the addition of bilirubin. Neither H-89, forskolin, nor PDA, nor their co-application with bilirubin affected mIPSC amplitudes of GABA-activated (I(GABA))/glycine-activated (I(gly)) currents, suggesting a presynaptic locus of activity. Chelerythrine decreased the mIPSC amplitudes and I(GABA)/I(gly), suggesting a postsynaptic locus of activity. These data suggest that both PKA and PKC can modulate GABA and glycine release in rat VCN neurons. Bilirubin facilitates transmitter release via presynaptic PKA activation, which might provide insight into the cellular mechanism underlying bilirubin-induced hearing dysfunction.


Assuntos
Bilirrubina/farmacologia , Núcleo Coclear/citologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Neurônios/efeitos dos fármacos , Proteína Quinase C/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Antioxidantes/farmacologia , Benzofenantridinas/farmacologia , Colforsina/farmacologia , Ativação Enzimática/efeitos dos fármacos , Glicina/metabolismo , Técnicas In Vitro , Isoquinolinas/farmacologia , Inibição Neural/efeitos dos fármacos , Técnicas de Patch-Clamp/métodos , Ésteres de Forbol/farmacologia , Ratos , Sulfonamidas/farmacologia , Ácido gama-Aminobutírico/metabolismo
6.
Artigo em Chinês | MEDLINE | ID: mdl-18512296

RESUMO

OBJECTIVE: To investigate the technique of the suprameatal approach for cochlear implantation in Chinese profound sensory hearing loss children. METHODS: Suprameatal approach for cochlear implantation were used in 50 cases (total 53 ears) with profound sensory hearing loss from May 2005 to January 2007. The electrode was passed through the suprameatal tunnel and went between the incus and chorda tympani into the scala tympani. RESULTS: Electrodes were completely inserted in 51 ears. There were no postoperative complications in all cases. Although the long effect need to be observed, all cases received better hearing and speech development benefit from cochlear implantation in the follow-up period. Among the 50 cases, 26 had speech perception in the open condition; 18 patients could speak short sentences although not clearly; and 6 patients learned to speak individual words only. CONCLUSIONS: The suprameatal approach was found to be a simple and safe technique that does not need mastoidectomy and avoid endangering the facial nerve and the chorda tympani. It enables wide exposure of middle ear and is especially suitable for cases with narrow facial recess or anteriorly located facial nerve.


Assuntos
Implante Coclear/métodos , Orelha/cirurgia , Perda Auditiva Neurossensorial/cirurgia , Adolescente , Grupo com Ancestrais do Continente Asiático , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino
7.
Hear Res ; 239(1-2): 126-40, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18348901

RESUMO

Gap detection has been used as an evaluation tool for temporal processing in subjects with sensorineural hearing loss (SNHL). However, the results from other reports are varied making it difficult to clearly define the impact of SNHL on the temporal processing ability of the auditory system. Specifically, we do not know if and how a high-frequency hearing loss impacts, presumably through off-channel interaction, the temporal processing in low-frequency channels where hearing sensitivity is virtually normal. In this experiment, gap-evoked responses in a low-frequency band (0.5-8 kHz) were recorded in the inferior colliculus (IC) and auditory cortex (AC) of guinea pigs through implanted electrodes, before and after a slopping high-frequency hearing loss, which was induced by over-stimulation using a 12-kHz-tone. The results showed that the gap thresholds in the low-frequency region increased gradually and became significantly higher 8 weeks after the induced high-frequency hearing loss. In addition, the response latency was slightly increased in the IC but this was not true for the AC. These results strongly indicate that a high-frequency hearing loss exerted an off-channel impact on temporal processing in the low-frequency region of the auditory system.


Assuntos
Córtex Auditivo/anatomia & histologia , Perda Auditiva de Alta Frequência/diagnóstico , Perda Auditiva Provocada por Ruído/diagnóstico , Colículos Inferiores/anatomia & histologia , Ruído , Estimulação Acústica , Acústica , Animais , Limiar Auditivo , Cóclea/patologia , Modelos Animais de Doenças , Eletrodos , Cobaias , Microscopia Eletrônica de Varredura , Órgão Espiral/ultraestrutura
8.
Artigo em Chinês | MEDLINE | ID: mdl-18335751

RESUMO

OBJECTIVE: To evaluate duration tuning in the inferior colliculus (IC) of guinea pigs and the role of GABA-mediated inhibition on this tuning. METHODS: Totally 23 healthy albino guinea pigs of either sex were employed in this study. After anesthesia, spikes of neurons in inferior colliculus were recorded using five-barrel glass-pipettes. The characteristic frequency was determined by recording iso-intensity response curves at moderate intensity level (40-70 dB SPL) and duration tuning was measured with signals of fixed intensity and varied durations. GABA-A receptor antagonist, bicuculline, was applied to neurons by means of in vivo micro-iontophoresis through one channel in the five-barrel glass-pipettes. RESULTS: IC neurons of guinea pigs, especially for those who showed sustained temporal response pattern, showed stronger duration tuning in their transient response peak to signal onset. Among 207 neurons recorded, totally 93 neurons were found to show clear duration selectivity. The duration selectivity was eliminated or turned to be weaker in most of the neurons in which the effect of bicuculline was observed successfully. CONCLUSIONS: Unlike what was reported in bats, duration selectivity may be a transient process for most of IC neurons in guinea pigs. Duration selectively of IC neurons in the guinea pig was also largely dependent on the GABAergic inhibition.


Assuntos
Colículos Inferiores/efeitos dos fármacos , Colículos Inferiores/fisiologia , Ácido gama-Aminobutírico/farmacologia , Animais , Potenciais Evocados Auditivos , Feminino , Cobaias , Colículos Inferiores/citologia , Masculino , Neurônios/efeitos dos fármacos , Neurônios/fisiologia
9.
Chin Med J (Engl) ; 119(12): 974-9, 2006 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-16805979

RESUMO

BACKGROUND: Ouabain, a cardiac glycoside that specifically binds to Na/K-ATPase and inhibits its activity, was applied to gerbils to develop a method for studying auditory neuropathy. METHODS: Ouabain was applied to the round window of the cochlea in each gerbil by using a piece of gelfoam with 3 microl or 24 microl (1 mmol/L) ouabain solution. The changes of the threshold of auditory brainstem response, cochlear function round window electrocochleography, as well as the morphological changes of the spiral ganglion cells of the cochlea were observed after application of ouabain for 24 hours or 96 hours. RESULTS: In ouabain treated gerbils, auditory brainstem response and compound action potential thresholds showed either elevation or no response at all. However, the thresholds of cochlear microphonic and distortion product otoacoustic emissions were not affected. Degeneration and necrosis of some spiral ganglion cells in ears with applications of ouabain (24 hours, 3 microl, 1 mmol/L; 96 hours, 24 microl, 1 mmol/L ouabain). The number of spiral ganglion cells was decreased (24 hours, 3 microl, 1 mmol/L ouabain) or near to a total loss (96 hours, 24 microl, 1 mmol/L ouabain). CONCLUSIONS: These results indicate a high degree of independence between the spiral ganglion cells and the outer hair cell systems in the cochlear transduction mechanism. The method used in this study would provide a valuable tool for studying auditory neuropathy.


Assuntos
Cóclea/efeitos dos fármacos , Ouabaína/toxicidade , Gânglio Espiral da Cóclea/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Animais , Cóclea/fisiologia , Potenciais Evocados Auditivos do Tronco Encefálico/efeitos dos fármacos , Gerbillinae
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