Previous animal studies have shown that stromal cell-derived factor-1 （SDF-1）/CXC chemokine receptor-4 （CXCR4） signaling pathway plays an important role in the targeted migration of bone marrow-derived mesenchymal...Previous animal studies have shown that stromal cell-derived factor-1 （SDF-1）/CXC chemokine receptor-4 （CXCR4） signaling pathway plays an important role in the targeted migration of bone marrow-derived mesenchymal stem cells （BMSCs） to the injured area. In the present study, we aimed to investigate the potential role of chemotactic SDF-1/CXCR4 signaling pathway in the homing of transplanted BMSCs to the injured cochlea after noise-induced hearing loss （NIHL） in a rat model. White noise exposure （110 dB） paradigm was used for hearing loss induction in male rats for 6 hours in 5 days. Distortion-product otoacoustic emission （DPOAE） responses were recorded before the experiment and post noise exposure.Hoechst 33342-labeled BMSCs and CXCR4 antagonist （AMD3100）-treated BMSCs were injected into the rat cochlea through the round window. SDF-1 protein expression in the cochlear tissue was assayed using western blot assay. The number of labeled BMSCs reaching the endolymph was determined after 24 hours.SDF-1 was significantly increased in the cochlear tissue of rats in the noise exposure group than in the control group. The number of Hoechst 33342-labeled BMSCs reaching the endolymph of the cochlea was significantly smaller in the AMD3100-treated BMSCs group than in the normal BMSCs group. Our present findings suggest that the SDF-1/CXCR4 signaling pathway has a critical role in BMSCs migration to the injured cochlea in a rat model of noise-induced hearing loss.展开更多
Objective： To report audiological characteristics in a group of noise-exposed crew members on board ships. Methods and materials： Clinical and audiological measurements including pure-tone thresholds, acoustic immit...Objective： To report audiological characteristics in a group of noise-exposed crew members on board ships. Methods and materials： Clinical and audiological measurements including pure-tone thresholds, acoustic immittance results and tinnitus questionnaires were collected from both the ship crew members （study subjects） and their land based colleagues （controls）. Results： 1） Noise exposed crew members showed not only high frequency, but also low frequency hearing loss; 2） Hearing impairment increased with age, with 65.5% of crew members younger than 50 years showing normal hearing while only 14.9% of those older than 50 years had normal hearing; 3） hearing loss gradually increased with the extension of on board career time; and 4） Most study subjects reported high pitch tinnitus, significantly more than the control group although not significantly different among different age groups. Conclusion： Noise induced hearing impairment from working on board ships shows specific frequency and age characteristics. Understanding these characteristics is important for advancing relevant studies and for effective prevention of noise-induced hearing loss in ship crew members.展开更多
Introduction: Noise is the second leading cause of hearing loss in adults after presbycusis. The objective of this work was to study hearing loss induced by the noise of mills in the markets of Parakou. Methods: This ...Introduction: Noise is the second leading cause of hearing loss in adults after presbycusis. The objective of this work was to study hearing loss induced by the noise of mills in the markets of Parakou. Methods: This was a descriptive and analytical cross-sectional study, conducted from February 3 to June 3, 2021 in the markets of Parakou. It concerned millers and sellers located within a 5 meter radius around the mills and among whom pure-tone audiometry was performed to detect a hearing loss. Subjects with no particular medical health history, under 55 years of age and having been working in these markets since more than 12 months, were included. Results: In this study, 103 subjects were selected, including 43 millers and 61 sellers. Their average age was 29 ± 13 years. The sex ratio was 0.49. The average length of service in the profession was 8 years with the extremes of 3 months and 47 years. They were exposed to noise on average 10 hours per day and 6 days a week. The average duration of weekly noise exposure was 23 h 28 min ± 13 h 32 min with the extremes of 5 h 00 min and 52 h 30 min. The average level of noise exposure was 90 dB with the extremes of 72 and 110 dB. 24 subjects reported symptoms related to noise such as headache, tinnitus, and hearing loss, with respective proportions of 22.33%, 20.39% and 06.80%. The prevalence of noise-related hearing loss was 26.21% (n = 27/103). Subjects with a notch at 4000 Hz and normal Average Hearing Loss (AHL) (20.39%) had a seven-time greater risk of developing noise-induced hearing loss (OR = 6.58;95% CI [2.54 - 18.8], p Conclusion: Hearing loss related to the noise of mills affected both millers and sellers near the mills in markets, hence the importance of regulating mills.展开更多
基金financially supported by the Hearing Disorders Research Center of Shahid Beheshti University of Medical Sciences
文摘Previous animal studies have shown that stromal cell-derived factor-1 （SDF-1）/CXC chemokine receptor-4 （CXCR4） signaling pathway plays an important role in the targeted migration of bone marrow-derived mesenchymal stem cells （BMSCs） to the injured area. In the present study, we aimed to investigate the potential role of chemotactic SDF-1/CXCR4 signaling pathway in the homing of transplanted BMSCs to the injured cochlea after noise-induced hearing loss （NIHL） in a rat model. White noise exposure （110 dB） paradigm was used for hearing loss induction in male rats for 6 hours in 5 days. Distortion-product otoacoustic emission （DPOAE） responses were recorded before the experiment and post noise exposure.Hoechst 33342-labeled BMSCs and CXCR4 antagonist （AMD3100）-treated BMSCs were injected into the rat cochlea through the round window. SDF-1 protein expression in the cochlear tissue was assayed using western blot assay. The number of labeled BMSCs reaching the endolymph was determined after 24 hours.SDF-1 was significantly increased in the cochlear tissue of rats in the noise exposure group than in the control group. The number of Hoechst 33342-labeled BMSCs reaching the endolymph of the cochlea was significantly smaller in the AMD3100-treated BMSCs group than in the normal BMSCs group. Our present findings suggest that the SDF-1/CXCR4 signaling pathway has a critical role in BMSCs migration to the injured cochlea in a rat model of noise-induced hearing loss.
基金supported by the National Basic Research Program of China(973 Program)(2014CB943002)the National Natural Science Foundation of China(81470700)Noise Grant(BWS14J045)
文摘Objective： To report audiological characteristics in a group of noise-exposed crew members on board ships. Methods and materials： Clinical and audiological measurements including pure-tone thresholds, acoustic immittance results and tinnitus questionnaires were collected from both the ship crew members （study subjects） and their land based colleagues （controls）. Results： 1） Noise exposed crew members showed not only high frequency, but also low frequency hearing loss; 2） Hearing impairment increased with age, with 65.5% of crew members younger than 50 years showing normal hearing while only 14.9% of those older than 50 years had normal hearing; 3） hearing loss gradually increased with the extension of on board career time; and 4） Most study subjects reported high pitch tinnitus, significantly more than the control group although not significantly different among different age groups. Conclusion： Noise induced hearing impairment from working on board ships shows specific frequency and age characteristics. Understanding these characteristics is important for advancing relevant studies and for effective prevention of noise-induced hearing loss in ship crew members.
文摘Introduction: Noise is the second leading cause of hearing loss in adults after presbycusis. The objective of this work was to study hearing loss induced by the noise of mills in the markets of Parakou. Methods: This was a descriptive and analytical cross-sectional study, conducted from February 3 to June 3, 2021 in the markets of Parakou. It concerned millers and sellers located within a 5 meter radius around the mills and among whom pure-tone audiometry was performed to detect a hearing loss. Subjects with no particular medical health history, under 55 years of age and having been working in these markets since more than 12 months, were included. Results: In this study, 103 subjects were selected, including 43 millers and 61 sellers. Their average age was 29 ± 13 years. The sex ratio was 0.49. The average length of service in the profession was 8 years with the extremes of 3 months and 47 years. They were exposed to noise on average 10 hours per day and 6 days a week. The average duration of weekly noise exposure was 23 h 28 min ± 13 h 32 min with the extremes of 5 h 00 min and 52 h 30 min. The average level of noise exposure was 90 dB with the extremes of 72 and 110 dB. 24 subjects reported symptoms related to noise such as headache, tinnitus, and hearing loss, with respective proportions of 22.33%, 20.39% and 06.80%. The prevalence of noise-related hearing loss was 26.21% (n = 27/103). Subjects with a notch at 4000 Hz and normal Average Hearing Loss (AHL) (20.39%) had a seven-time greater risk of developing noise-induced hearing loss (OR = 6.58;95% CI [2.54 - 18.8], p Conclusion: Hearing loss related to the noise of mills affected both millers and sellers near the mills in markets, hence the importance of regulating mills.
