RESUMEN
Background: The noise is considered as a factor of environmental stress, causing a wide range of health effects such as acoustic, cardiovascular, nervous and endocrine systems
Purpose: The present study was conducted to examine the affects of repeated exposure to noise on the peripheral auditory system, adrenal gland and heart tissue
Method: The White strain rats "Wistar" were exposed to chronic and repetitive exposure noise at two different intensity levels of 70 and 85dB [A]. The noise level was generated by the Audacity® software to an octave-band noise [8616 kHz]. The sound exposure duration was 6 hr/day, 5 days per week for 3 months. Quantitative and qualitative investigations were performed by using electron microscopy. The ganglion neuron counting was examined via light microscopy
Results: The results show that exposure to sound intensities 70 and 85 dB [A] for long periods, lead to changes in the morphological structure of the cochlea [inner ear], adrenal cortex and cardiac tissue which involve cell disruption which over time can lead to pathological effects
Conclusion: This study provides morphological evidence that repetitive exposure noise at moderate sound levels to 70 and 85 dB [A] induces changes in the peripheral auditory system, the adrenal cortex and heart tissue
RESUMEN
In Tunisia, eight researches works, dealing with low back trauma [LBT], have been achieved in some occupational sector activities and only 2 of them have been published. To synthesize data provided by these 8 works realized between 1998 and 2007, in order to estimate the disorder magnitude and to describe LBT victims profile in Tunisia. The global population of study is made of 1357 LBT victims [977 belonging to the private sector and 380 to the public sector]. The data collection was carried out according to an uniformed model for the 8 studies. In the public sector, Commission Mdicale Centrale data show that LBT account for 4 to 5% of occupational accidents [OA] and that their annual incidence is from 32 to 36/100000. In the private sector, Caisse Nationale d'Assurance Maladie data reveal that LBT account for 7.7% to 9.5% of OA. LBT victim is a male [83%], with an age ranging between 36 and 43.5 years, married [84%], educated up to the secondary educational [91%] with a vertebral disorders history [34%]. He belongs to the general-purpose workmen category in 1/2 of cases with an average seniority ranging between 7.8 and 16.2 years. LBT almost subjects, get at least of a sick leave. Work days lost is around 210 days for the private sector and 18 days for the public. The per annum amount versed for each LBT case, within the framework of the Total Temporary incapacity, is of 1449.319 DT and 45% of the subjects profit from a professional reclassification. Our results join those of international studies having dealt with LBD in professional environment. In spite of some limiting methodological issues, they allowed us to provide to professionals in occupational health useful data for this occupational risk management