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Zhonghua er bi yan hou tou jing wai ke za zhi = Chinese journal of otorhinolaryngology head and neck surgery 03/2011; 46(3):180-2.
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ABSTRACT: Salicylate, a common drug frequently used long term in the clinic, is well known for causing reversible hearing loss and tinnitus. Our previous study, however, demonstrated that chronic administration of salicylate progressively raised the amplitude of distortion product of otoacoustic emissions (DPOAEs), which are mainly caused by (outer hair cell) OHC electromotility. How salicylate affects OHC electromotility to cause this paradoxical increase remains unclear. One possibility is that it could affect prestin, which is a motor protein that contributes to the mechano-electrical properties of OHCs. In this experiment, we assessed the effect of acute and chronic salicylate treatment on prestin expression. Interestingly, after long-term salicylate injection (200 mg/kg, twice daily for 14 days), prestin gene and protein levels were up-regulated about twofold. These levels returned to baseline 14 days after treatment stopped. Acute injection of salicylate (single injection, 400 mg/kg) did not affect prestin levels. These data reveal that chronic salicylate administration markedly, but reversibly, increased prestin levels which may contribute to the enhanced DPOAE amplitudes we observed previously with similar salicylate treatment, which may be responsible for salicylate-induced tinnitus generation.
International journal of audiology 02/2009; 48(1):18-23. · 1.34 Impact Factor
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ABSTRACT: Auditory transduction in the cochlear is subject to modulate higher auditory centers in the brain via the efferent systems, which provide protection against damage caused by excessive excitation during auditory over stimulation. GABA is a proven inhibitory neurotransmitter in the efferent systems in mammalian cochlear. KCC2 is a neuron-specific potassium chloride cotransporter whose role in mature central neurons is to maintain the low intracellular Cl(-) concentrations required for the hyperpolarizing responses to the inhibitory amino acids GABA and glycine. However, there is a lack of information concerning KCC2 expression in the mammalian cochlear. In this study, reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were used to detect the expression and localization of KCC2 in the mammalian cochlear. The results showed that these neuron-specific KCC2 transporters were present in most spiral ganglion neurons (SGNs) corresponding to the distribution of GABA(A)Rs. In addition, less intense reactions were observed on the organ of Corti, stria vascularis, and fibrocytes of the spiral ligament. These data suggest that KCC2 may play an important role in the modulation of a GABA neurotransmitter's function in a mammalian cochlear. Moreover, the presence of KCC2 on the organ of Corti and its surrounding tissues may contribute to maintaining normal K+ cycling. It is also presumed to be related to Cl(-) transportation in hair cells.
Neuroscience Letters 09/2008; 441(2):205-9. · 2.11 Impact Factor
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ABSTRACT: The cochlea can be protected from acoustic trauma by moderate-level sound exposure. It is suggested that olivocochlear system may play a significant role in this protection. This study was performed to investigate distortion product otoacoustic emission (DPOAE) amplitudes changes and the efficiency of contralateral noise stimulation on DPOAE after conditioning noise exposure. Our results demonstrate that long-term conditioning can increase the DPOAE amplitudes at low frequencies (1.0-3.0 kHz) and decrease the olivocochlear efferent reflex strength at the same frequencies. The DPOAE amplitudes are partially restored to the preconditioning levels 2 weeks after conditioning; contralateral suppression also returns to the preconditioning levels. These results suggest that the enhancement of DPOAE amplitudes might be due to a decrease in olivocochlear efferent reflex strength.
Neuroreport 08/2007; 18(11):1167-70. · 1.66 Impact Factor
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ABSTRACT: To investigate the effects of personal listening device use on hearing in young listeners.
Conventional frequency audiometry (0.5-8 kHz) and extended high-frequency audiometry (10-20 kHz) were performed on 120 personal listening device users and 30 normal-hearing young adults.
The hearing thresholds in the 3 to 8 kHz frequency range were significantly increased in the personal listening device listeners. The frequency range of the increased thresholds became broad as the exposure duration was increased. Impaired hearing was detected in 14.1% (34 of 240 ears) of ears (> 25 dB HL in one or more frequencies in 0.5-8 kHz). The hearing thresholds of extended high-frequency audiometry in personal listening device users could also be increased even if their hearing thresholds in conventional frequency audiometry were normal.
Our results suggest that long-term use of personal listening devices can impair hearing function The data also indicate that extended high-frequency audiometry is a sensitive method for early detection of noise-induced hearing loss.
The Journal of otolaryngology 07/2007; 36(3):181-5. · 0.50 Impact Factor
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ABSTRACT: Aspirin (salicylate) is a common drug and frequently used long term in the clinic. It has been well documented that salicylate can cause reversible hearing loss and tinnitus and diminish outer hair cell (OHC) electromotility, which is capable of actively boosting the basilar membrane vibration and producing acoustic emission. However, aspirin's ototoxic mechanisms still remain largely unclear. In this experiment, the effects of long-term salicylate administration on cochlear hearing functions were investigated by measuring distortion product otoacoustic emissions (DPOAEs) in awake guinea pigs. A single injection of sodium salicylate (200 mg/kg) could reduce the amplitude of the cubic distortion product of 2f1-f2 within 2 h. The reduction was significant at 20-50 dB SPL stimulus levels and recovered after 8 h. However, following daily injections of sodium salicylate (200 mg/kg, b.i.d.), the distortion product of 2f1-f2 progressively increased. After injection for 14 days, the distortion product increased about 2-3.5 dB SPL. The increase rate was about 0.2 dB SPL/day. The DP-I/O function remained nonlinear. The increase was greater at 40-70 dB SPL primary sound intensities and reversible. After cessation of salicylate treatment for 4 wk, the increased distortion product returned to the initial normal levels. The rate of recovery was 0.1 dB SPL/day. In the control animals with saline injection, there was no change in DPOAEs. The data revealed that long-term administration of salicylate could paradoxically enhance active cochlear mechanics. The data also suggested that salicylate-induced tinnitus might be generated at the OHC level.
Journal of Neurophysiology 05/2005; 93(4):2053-61. · 3.32 Impact Factor
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ABSTRACT: To study the mechanism of electrophysiologic changes caused by different type of sodium salicylate injection.
Decapitated three group rats ( acute injected, chronic injected and normal rats ) separately, dissected the temporal bones to collect cochlea, and the otic capsules were removed. Then the cochlear materials from each groups were pooled and homogenized respectively, extracted the total RNA, obtained cDNA from purified total RNA by reversed transcription, cDNA were transcripted to cRNA probes in vitro. Hybridized the cRNA probes with tester chip to evaluate the quality of probes, if good, hybridized the probes with real chip. Obtained three gene expression profiles of different groups of cochlea Analyzed the differentially expressed genes among three groups by SOM. Analogized the SOM result to electrophysiologic changes. Then analyzed the genes in clusters of analog results by Gene Ontology. Then the genes in clusters of analog results were analyzed by Gene Ontology. Hsp27 was chosen to validate the result of gene chip using real time quantitative reverse transcription PCR ( RTQ RT-PCR).
The probes was good, and the chip hybridization results was credible. We obtained 6 clusters genes by SOM analysis, in which we choose cluster 3 and cluster 4 as candidate cluster. There were 46 genes in cluster 3 and 30 genes in cluster 4 employing GO analysis, which involved in cell communication, cell motility, metabolism, immune response and nerve ensheathment, et al. The result of RTQ RT-PCR showed high concordance with that of gene chip.
It's a new method to study the mechanism of electrophysiologic changes caused by sodium salicylate by gene chip and SOM analysis.
Zhonghua er bi yan hou tou jing wai ke za zhi = Chinese journal of otorhinolaryngology head and neck surgery 02/2005; 40(1):27-32.
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Zhonghua yi xue za zhi 03/2003; 83(4):270-1.
