Risk factors analysis of low back pain among workers in a foundry factory of the automobile company / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the main risk factors of low back pain of workers ina foundry factory of the automobile company using cross sectional epidemiological investigation, and to provide scientific base for preventing the disorder.</p><p><b>METHODS</b>The low back pain and work loads of 1340 workers in a foundry factory of the automobile company were investigated using questionnaire, and logistic regression analysis was used to analyze the risk factors.</p><p><b>RESULTS</b>The one-year morbidity of low back pain in workers was 58.9% the morbidities of low back pain in workers engaged in foundry, transportation and modeling were 64.6%, 64.6% and 62.5%, respectively. The lifting with squat postures, bending trunk heavily, bending trunk with twisting and moving the heavy objects were found to be the most dominant risk factors for low-back pain, the OR values were 2.085, 1.961, 1.967 and 1.956, respectively. The distributions of risk factors were different among the different jobs. The logistic regression analysis showed that moving the heavy objects, lifting with squat postures, bending trunk heavily, bending trunk with twisting existed simultaneously, also the work years and gender were the risk factors.</p><p><b>CONCLUSION</b>The manual moving heavy objects, awkward working posture or both were the most important risk factors for low-back pain. The intervene ergonomic study should be performed in future to reduce the morbidity of low-back pain.</p>

A field assessment on the risk factors of musculoskeletal disorders / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the usability of quick exposure check (Quick Exposure Check, QEC) for the field assessment of occupational musculoskeletal disorder risk factors.</p><p><b>METHOD</b>In the shipyard and automobile manufacturing plants, QEC was used to observe the operations among workers with different jobs and to assess the work loads of workers. On the basis of results, the reliability of QEC was evaluated, and the correlation between QEC scores and morbidities of musculoskeletal disorders in workers was analyzed.</p><p><b>RESULTS</b>The inter-observer reliability (ICC) was in the range from 0.737 to 1.000, and intra-observer reliability (Spearman coefficient) was from 0.605 to 1.000. The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the shipyard factory was plumbers > assemblers > welders; The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the automobile factory was welders > punching workers > machinists > casters > assemblers. In different body parts, the exposure level at back and neck parts was the highest and the exposure level at the shoulder and wrist parts was the second. The regression analysis between QEC scores of body parts and the morbidities of musculoskeletal disorders showed that there was a good correlation between exposure levels and morbidities, the coefficients (r(2)) at the shoulder, wrist, and back (static work) were 0.670, 0.740 and 0.958, respectively (P < 0.05).</p><p><b>CONCLUSION</b>The QEC method is suitable and reliable as demonstrated by the field assessment on the exposure to risk factors in shipyard and automobile workers, and its results is correlated closely to the disease prevalence.</p>

Effect of Hg2+ on voltage-dependent calcium channels and intracellular free calcium in trigeminal ganglion neurons of rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of Hg2+ on voltage-dependent calcium channels and intracellular free calcium in trigeminal ganglion neurons of rats and explore the toxicity mechanism of Hg2+ on these neurons.</p><p><b>METHODS</b>Whole cell patch-clamp technique was used to determine ICa of voltage-dependent calcium channels in trigeminal ganglion neurons of rats. Intracellular free calcium was measured to explore [Ca2+]i dynamic changes from a single cell level by laser scanning confocal microscopy and fluorescence probe techniques.</p><p><b>RESULTS</b>0.01, 0.10, 1.00 and 10.00 micromol/L Hg2+ could reduce voltage-dependent calcium channel currents ICa by (1.80+/-0.32)%, (23.04+/-9.46)%, (58.20+/-7.90)% and (82.00+/-5.77)% in trigeminal ganglion neurons. The inhibiting effects reached their maximum in 5 minutes and could not be reversed significantly during wash with Hg2+-free solution. Also, 0.01, 0.10 and 1.00 micromol/L Hg2+ increased intracellular free calcium concentrations by (2.50+/-0.83)%, (82.81+/-35.36)% and (222.70+/-62.48)% in trigeminal ganglion neurons. Pre-administrated trigeminal ganglion neurons with nifedipine for 10 minutes could decrease the effects and delay the effecting time.</p><p><b>CONCLUSION</b>The inhibition of Hg2+ on the voltage-dependent calcium channel currents ICa depends on voltage-dependent calcium channels. And the increase of intracellular free calcium concentration in trigeminal ganglion neurons induced by Hg2+ is related to the release of intracellular stored calcium. However, the relationship between them needs further investigation.</p>

Expressions of collagen in lung of rats exposed to ammonium perchlorate / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the influence on expression of interstitial collagen in lung of rats exposed to ammonium perchlorate.</p><p><b>METHODS</b>The rats were treated with AP by intratracheal instillation and sacrificed after 3 d, 7 d, 14 d, 28 d. The mRNA level of collagen I and collagen III in the lung tissues was measured by RT-PCR.</p><p><b>RESULTS</b>The levels of collagen I on 7 d, 14 d, 28 d exposed for high dose group (1.93 +/- 0.41, 3.50 +/- 0.90, 2.33 +/- 1.12) and 28 d exposed for medial dose group (2.58 +/- 0.86) were higher significant (P < 0.05) than those in negative control group (0.52 +/- 0.11, 0.77 +/- 0.15, 0.86 +/- 0.29) The levels of collagen I in low dose group exposed for 14 d(1.99 +/- 0.67), 28 d(1.85 +/- 0.67) and high dose group 14 d(3.50 +/- 0.90) exposed for 14 d were higher significant (P < 0.05) compared to those exposed to AP for 3 d(0.52 +/- 0.14), (1.71 +/- 0.38). The levels of collagen III on 14 d, 28 d exposed for high dose group (2.60 +/- 1.00, 1.46 +/- 0.36) and 14 d, 28 d exposed for medial dose group (1.80 +/- 0.51, 2.16 +/- 0.87) were higher significant (P < 0.05 or P < 0.01) than those in negative control group(0.54 +/- 0.20, 0.52 +/- 0.22); The levels of collagen III in medial dose group(2.16 +/- 0.87) exposed for 28 d, and high dose group exposed for 14 d (2.60 +/- 1.00) were higher significant (P < 0.05) compared to those exposed to AP for 3 d(1.22 +/- 0.32, 0.96 +/- 0.17).</p><p><b>CONCLUSION</b>The results suggest that AP has a toxic effect to promote the expressions of collagen I and collagen III mRNA in lungs of rats, and may be cause fibrosis, but there should have more suffice evidences to prove that AP is exactly compound that made lung fibrosis.</p>