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báo cáo hóa học: " Uniform comparison of several drugs which provide protection from noise induced hearing loss"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Uniform comparison of several drugs which provide protection from noise induced hearing loss | Tamir et al. Journal of Occupational Medicine and Toxicology 2010 5 26 http www.occup-med.eom content 5 1 26 RESEARCH JOURNAL OF OCCUPATIONAL MEDICINE AND TOXICOLOGY Open Access Uniform comparison of several drugs which provide protection from noise induced hearing loss c I I I r 1 Í I 1 A u I - 2WCCr M AMW r3 I I I c I r4 Sharon idiTiir Cahtia Adelman Jeffrey M Weinberger Haim sohmer Abstract Background The ability of drugs to reduce noise induced hearing loss NIHL has been evaluated in diverse experimental conditions animal species noise intensities durations assessment techniques etc making it difficult to assess their relative efficacy. The present study was designed to provide more uniform comparisons and to allow to a better understanding of the mechanism of the NIHL. Methods The drugs studied included furosemide loop diuretic and the antioxidants N Acetyl-L-Cysteine vitamins A c E with the vasodilator magnesium. Mice were exposed to a continuous broadband noise 113 dB SPL for 3.5 hours and the NIHL was assessed in all animals before noise exposure and 1 week after with auditory nerve brainstem evoked responses ABR to broadband clicks and to 8 kHz tone bursts. Results Each of the drugs alone and in combination led to similar reductions in NIHL. Conclusions The loop diuretic furosemide by reducing the magnitude of the endocochlear potential in scala media probably depressed active vibrations of the outer hair cells and basilar membrane resulting in reduction of free radical formation during the noise exposure. The antioxidants N Acetyl-L-Cysteine and vitamins A C E with the vasodilator magnesium presumably counteract the free radicals. Thus the administration of the antioxidants to animals in which free radical formation had already been reduced by previous injection of furosemide did not have an additional protective effect on the NIHL. Background Noise induced hearing loss NIHL leads to a decrease in quality of life and therefore it has become a major .