[Protective effect of N-acetylcysteine on blocking potentiation of noise induced hearing loss by carbon monoxide in rabbits]

Noise induced hearing loss [NIHL] is one of the most important occupational diseases worldwide. NIHL has been found to be potentiated by simultaneous carbon monoxide [CO] exposure. This study was performed to evaluate the protective effect of Nacetylcysteine [NAC] administration on potentiating effect of CO on NIHL in rabbits. In this experimental study forty-two male adult white rabbits were divided into seven groups [n=6 for each group]. Group 1, as control [no exposure to noise or CO and no injection]; Group 2, noise exposure [100 dB for 40 h]; Group 3, noise+CO exposure; Group 4, noise exposure+NAC administration [325 mg/kg]; Group 5, noise+CO exposure+NAC administration, Group 6, NAC administration alone and Group 7, CO exposure [700 ppm for 40h]. Audiometric test of rabbits was assessed by Auditory Brain stem Response [ABR] test in three stages: before exposure, 1 hour and 14 days post exposure at 1, 2, 4 and 8 kHz frequency. The administration of NAC attenuated temporary and permanent ABR threshold shift caused by noise exposure and simultaneous exposure to noise plus CO. NAC administration blocked the potentiating of temporary threshold shift by CO at 1, 2, and 4 KHz frequency and also blocked potentiating of permanent threshold shift by CO at all frequencies. NAC as an antioxidant agent can attenuate temporary and permanent noise induced ABR threshold shifts and provides protective effect against potentiating of NIHL by CO in rabbits

[Evaluating the correlation between burnout syndrome dimensions and demographic characteristics of cashiers in state banks of Kashan]

Burnout syndrome as a serious occupational disorder has recently been focused by researchers. Three main dimensions of burnout syndrome are emotional exhaustion, depersonalization and reduced personal accomplishment. This syndrome leads to physiological and psychological stresses and diminishes the staff interest and work efficiency. This study was designed to assess the correlation between burnout syndrome dimensions and demographic characteristics of cashiers in state banks of Kashan in 2010. This cross-sectional study was conducted on 156 cashiers in sate banks of Kashan. Frequency and severity of burnout syndrome were evaluated using Maslach burnout inventory [MBI]. Demographic characteristics of subjects were collected through a specific questionnaire. Data were analyzed using chi-square test. In frequency twenty-seven [17.3%] and in severity 12 [7.7%] of subjects showed the most emotional exhaustion. The most reduced personal accomplishment was in frequency in 24 [15.4%] and in severity in 27 [17.3%] participants. Also the most depersonalization was in 21 [13.5%] and in 14 [9%] subjects in frequency and in severity, respectively. There was a significant relationship between age, gender, work records and marital status with emotional exhaustion and reduced personal accomplishment of banks' cashiers. Emotional exhaustion and reduced personal accomplishment have a significant relationship with demographic characteristics

[Prevalence of musculoskeletal disorders and work-related risk factors among the employees of an automobile factory in Tehran during 2009-10]

Work-related musculoskeletal disorders are considered as one of the most common occupational diseases and injuries. The high prevalence of the disorders has been reported in automobile industries due to numerous risk factors. This study was conducted to determine the prevalence of musculoskeletal disorders and the work-related risk factors in an automobile factory in Tehran. This cross-sectional study was performed on 145 workers in an automobile factory in Tehran during 2009-10. The prevalence of disorders was evaluated with standard Nordic questionnaire and work-related risk factors with KIM index. Data analyzed using chi-square test. Musculoskeletal disorders were most commonly seen in tire installing [92.8%] and exhaust storage installing [88.4%] units. It was least common in door installing [43.7%] unit. Awkward posture, load lifting, back bending and torsional movements were the most important work-related risk factors for the disorders. A significant relationship was observed between prevalence of musculoskeletal disorders and occupational risk level [P<0.05]. Ergonomics programs and specific ergonomic interventions are necessary to correct work-related problems in the work stations of this industry

[Effect of simultaneous noise and carbon monoxide exposure on rabbits' auditory brain stem response]

Background: Noise induced hearing loss [NIHL] is one of the most important occupational diseases worldwide. NIHL has been found to be potentiated by some of air pollutants. Exposure to noise plus carbon monoxide is common in occupational and environmental settings. This study was performed to evaluate the effect of noise and carbon monoxide exposure simultaneously on rabbits' hearing system by Auditory Brain stem Response [ABR] assessment

Materials and Methods: In this experimental study, 24 male adult white rabbits were divided to four groups: control group, noise exposure group, noise plus carbon monoxide exposure group and carbon monoxide exposure group. Auditory Brain stem Responses of the four groups were determined: before exposure, 1 hour after exposure and 14 days after exposure by click and tone burst stimulus

Results: The latency mean time of V wave in the ABR test for the group exposed to noise plus carbon monoxide, 1 hour after exposure at 1, 2, 4 and 8 KHz frequency were respectively 5.43+/-0.08, 5.50+/-0.07, 5.71+/-0.07 and 5.75+/-0.07 millisecond. These values were significantly more than the same values in the other groups

Conclusion: NIHL may be potentiated by carbon monoxide in the simultaneous exposure. Thus, it seems occupational and environmental exposure to noise plus carbon monoxide may increases hearing loss risk