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Objective To investigate the combined effect of noise and hand-transmitted vibration on hearing loss in male noise-exposed workers. Methods A total of 952 male noise-exposed workers from an automobile manufacturing enterprise were selected as the research subjects using judgment sampling method. Occupational epidemiological surveys, assessments of occupational hazards in workplace, and pure-tone audiometry tests were conducted on the research subjects, and they were divided into low-level noise group, low-level combined group, high-level noise group, and high-level combined group according to whether the noise exposure level exceeded the national standard and whether they were jointly exposed to hand-transmitted vibration. The joint effects of noise and hand-transmitted vibration on hearing loss were analyzed. Results The detection rate of hearing loss in 952 noise-exposed workers was 21.7%. The detection rate of hearing loss of four groups, from high to low, was as follows： high-level combined group, high-level noise group, low-level combined group, and low-level noise group (44.9% vs 32.7% vs 12.9% vs 5.7%, P<0.01). The results of multivariate logistic regression analysis showed that the risk of hearing loss in the low-level noise group, the low-level combined group, the high-level noise group and the high-level combined group increased sequentially after adjusting for the confounding factors such as age, education level, smoking, drinking, listening to music with headphones, frequency of wearing noise-blocking earplugs and body mass index. The risk of hearing loss in the high-level noise group was 8.62 times more than that of the low-level noise group (P<0.01). The risk of hearing loss in the low-level noise combined group was 2.50 times more than that of the low-level noise group (P<0.01). The risks of hearing loss in the high-level combined group were 5.76 and 1.67 times more than that of the low-level combined group and the high-level noise group. Conclusion Combined exposure to noise and hand-transmitted vibration can increase the risk of hearing loss in male noise-exposed workers, and the higher the noise intensity, the greater the synergistic effect. Hand-transmitted vibration is a synergistic risk factor for occupational noise-induced hearing loss.
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Objective@#To explore the impact of welding operations on the health status of workers with low working age, and provide a basis for occupational health risk assessment for workers of low working age.@*Methods@#Used the method of cluster sampling to randomly selected workers from an automobile manufacturing plant in Guangzhou as research subjects: 982 workers with welding posts of 1 year ≤working age ≤5 years were welding groups, 707 workers with simple exposure noise of 1 year ≤working age ≤5 years were assembly groups, and 717 workers in pre-job medical examinations were pre-job groups from June 2017 to September 2018. Then conducted occupational health checks on all subjects, investigated and detected the occupational hazards in welding posts and assembly posts.@*Results@#There was no statistical difference between the noise over-standard rate of welding posts' (59.3%, 16/27) and the assembly posts' (47.4%, 9/19) (P>0.05) . The over-standard rate of welding fume, manganese and its inorganic compounds in welding posts was 11.11% (3/27) . The results of occupational health examination showed that the detection rate of disease or abnormal of the welding group was 78.4% (770/982) higher than 70.2% (496/707) in the assembly group and 53.0% (380/717) in the pre-job group (the value of 2 were 14.92 and 122.37, respectively, P<0.05) . The rate of hearing loss of the assembly group and the welding group were 14.7% (104/707) and 19.3% (190/982) , respectively, which was higher than that of the pre-job group (10.5%, 75/717) , and the hearing loss rate gradually increased with the increase of working age (the value of linear-by-linear association were 12.04 and 44.67, respectively, P<0.01) . Compared with the hearing loss rate of each working age of the assembly group, the hearing loss rate of each working age of the welding group was higher, and when the working age was 3 years, the risk of hearing loss in the welding group was 2.70 times that of the assembly group (P<0.01) . The rate of pulmonary dysfunction in the welding group was 19.2% (189/982) higher than that in the pre-job group (12.6%, 90/717) , and it increased with the increase of working age (the value of linear-by-linear association was 15.97, P<0.01) .@*Conclusion@#Welding work seriously damages the health of workers with low working age, increases the hearing loss of workers and the occurrence of pulmonary dysfunction; manganese and its compounds increases noise-induced damage to the hearing system.
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OBJECTIVE: To explore the effect of wearing earphone to listen to music on the high-frequency noise-induced hearing loss(NIHL) in noise-exposure workers. METHODS: A total of 651 male noise-exposure workers in an automobile manufacturer were selected as study subjects by using judgment sampling method. The level of noise exposure in the individuals and the pure tone hearing threshold were tested. According to the frequency of wearing earphone to listen to music after work, the subjects were divided into low-, medium-and high-frequency earphone-using groups, with 60, 436 and 155 workers in each group, respectively. The effects of wearing earphone to listen to music combined with occupational noise exposure on high-frequency NIHL were analyzed. RESULTS: The high-frequency NIHL detection rate of the study subjects was 31.3%(204/651). The detection rate of high-frequency NIHL in these three groups from low to high was low-, medium-and high-frequency earphone-using groups(P<0.01). The detection rate of high-frequency NIHL in the high-frequency earphone-using group was higher than that of the low-and medium-frequency earphone-using groups(43.2% vs 25.0%, 43.2% vs 28.0%, P<0.01). Multivariate logistic regression analysis showed that wearing earphones to listen to music was a risk factor for high-frequency NIHL in noise-exposure workers(P<0.01) after eliminating the influence of confounding factors such as age, length and level of noise-exposure, and wearing anti-noise ear plugs. The higher frequency of wearing earphone to listen to music, the higher risk of high-frequency NIHL. CONCLUSION: Wearing earphone to listen to music after work and occupational noise exposure had a synergistic effect on high-frequency NIHL in noise-exposure workers.
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OBJECTIVE: To observe the status of protein kinase B(Akt) signaling pathway in Akt phosphorylation induced by free silica(SiO_2) in mouse monocyte macrophage cell RAW264.7, and the role of Akt signaling pathway in early inflammatory response of silicosis. METHODS: i) RAW264.7 cells were routinely cultured and divided into SiO_2 stimulation groups at 5 different time points, and were stimulated for 15, 30, 60, 120 and 240 minutes with SiO_2 suspension with a final concentration of 100 mg/L, and a control group without SiO_2 treatment. At the end of treatment, the cells were collected and the expression of phospho-(Ser/Thr) Akt(p-Akt) was detected by Western blotting to select the optimal time of treatment. ii) RAW264.7 cells were divided into control group(no treatment), SiO_2 exposure group(previous concentration of 100 mg/L SiO_2 suspension) and intervention group(pre-treated with Akt activation inhibitor deguelin for one hour and then treated with 100 mg/L SiO_2 suspension), samples were collected after incubation for 60 minutes. The p-Akt expression and distribution in cells were detected by cellular immunofluorescence assay, the relative expression of p-Akt in cells was detected by Western blotting, and the levels of tumor necrosis factor-α(TNF-α) and transforming growth factor-β1(TGF-β1) in the supernatant of cells were detected by enzyme-linked immunosorbent assay. RESULTS: i) The optimal treatment time of RAW264.7 cells for SiO_2 exposure model was 60 minutes in vitro. ii) The results of cellular immunofluorescence assay showed that Akt phosphorylation was activated in RAW264.7 cells after stimulant with SiO_2, and the fluorescence of p-Akt was enhanced in the SiO_2 exposure group than the control group, and in the intervention group it was relatively weaker than the SiO_2 exposure group. The relative expression of p-Akt as well as the levels of TNF-α and TGF-β1 in the SiO_2 exposure group and the intervention group were higher than that in the control group(P<0.05), and the above three idexes in the intervention group were lower than the SiO_2 exposure group(P<0.05). CONCLUSION: Akt signaling pathway is involved in the process of SiO_2-induced macrophages phosphorylation, and participates in the early inflammatory response of silicosis.
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Objective@#To study the effect of sodium aescinate on the development process of lung injury induced by paraquat.@*Methods@#Forty-five health adult male SD rats were randomly divided into control group, PQ group, sodium aescinate group, and 15 rats in each group. The PQ group and sodium aescinate group were given a one-time intraperitoneal injection of 18mg/kg body weight of rats PQ, the control group was given the same amout normal saline. Rats in sodium aescinate group were injected 2 mg/kg body weight sodium aescinate into abdominal cavity for 7 days continually, but the same volume of saline was injected into the other groups. Finally, at 7, 14 and 28 days after PQ poisoning, five rats were kills for measuring lung tissue pathological changes and the value of TGF-β1, TNF-α, hydroxyproline in each group.@*Results@#The expression of TNF-α in serum of 7th day [ (17.03±0.82) ng/ml] and 14th day [ (15.74±0.91) ng/ml] of sodium aescinate group were lower than the corresponding period of PQ groups’, and the difference had statistical significance (P<0.05) . The expression of TGF-β1 in serum of 7th day[ (225.93±8.33) ng/ml], 14th day [ (216.62±9.48) ng/ml] and 28th[ (181.41±6.10) ng/ml] of sodium aescinate group were lower than the corresponding period of PQ groups’, and the difference had statistical significance (P<0.05) . Lung tissue pathological changes showed, compared with control group, inflammatory injury at 7th day and fibrosis degree at 28th of rats’ lung reduced on sodium aescinate group. The expression of hydroxyproline in rats’ lung of 7th day[ (1.246±0.018) μg/mg], 14th day [ (1.269±0.034) μg/mg] and 28th[ (1.283±0.028) μg/mg] of sodium aescinate group were lower than the corresponding period of PQ groups’, and the difference had statistical significance (P<0.05) .@*Conclusion@#sodium aescinate could reduce the pulmonary inflammatory injury and hydroxyproline value of PQ poisoning rats, so sodium aescinate could ameliorate lung injury induced by PQ.
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Objective@#To study the hearing status and analyze the related influencing factors in noise-exposed workers in an automobile manufacture enterprise, and put forward suggestions for prevention of noise-induced hearing loss.@*Methods@#Noise exposure level testing, audiometry testing and questionnaires were performed for noise exposed workers in the automobile manufacture enterprise. To analyze the relationship between different factors and noise-induced hearing loss by cumulative noise exposure(CNE) calculated 8-hour continuous A-weighted equivalent noise level and seniority.@*Results@#The detection rate of hearing loss in noise-exposed workers was 22.8%. The noise exposure intensity of stamping workshop is higher than other workshop, and the hearing loss detection rate of stamping workshop workers is higher than other workshop workers. The detection rate of hearing loss has significant difference in LAeq·8 h, seniority, CNE, age, high temperature and wearing earplugs (P<0.05). The results of logistic regression analysis showed that CNE, age and high-temperature were risk factors for noise-induced hearing loss (P<0.05 and OR>1) and there was an increasing tendency of hearing loss with increase in length of service and CNE, while using of earplugs was a protective factor (P<0.05 and OR<1). With the increase of CNE, the incidence of hearing loss is the rising trend.@*Conclusion@#It is suggested to strengthen the noise control and individual protection and improve the high-temperature working environment, which plays an important role in reducing the occurrence of noise-induced hearing loss.
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Objective@#To investigate the role and mechanism of action of green tea polyphenols in noise-induced hearing loss.@*Methods@#Male specific pathogen-free guinea pigs were randomly divided into normal control group with 9 guinea pigs, noise exposure group with 36 guinea pigs, and green tea polyphenol intervention group with 36 guinea pigs. Auditory brainstem response (ABR) threshold shift was examined before noise exposure and at 1, 3, 7, and 14 days of noise exposure. The surface preparation of cochlear basilar membrane was used for hair cell count and the morphology of hair cells was also observed. Western blot was used to observe the expression of cysteinyl aspartate-specific protease-9 (caspase-9) and cysteinyl aspartate-specific protease-3 (caspase-3) in cochlear tissue.@*Results@#Both the noise exposure group and the green tea polyphenol intervention group had an increase in ABR threshold after noise exposure, and the green tea polyphenol intervention group had a significantly lower ABR threshold shift than the noise exposure group at all time points (P<0.05). Both groups had enlargement, atrophy, or loss of hair cells after noise exposure, and at 7 and 14 days of noise exposure, the noise exposure group had a significantly higher rate of abnormal hair cells than the green tea polyphenol intervention group (P<0.05). Both groups had an increase in the expression of caspase-9 and caspase-3 after noise exposure, and the noise exposure group had a significantly greater increase than the green tea polyphenol intervention group (P<0.05).@*Conclusion@#Green tea polyphenols can reduce noise-induced hearing loss and hair cell injury, possibly by regulating the expression of caspase-9 and caspase-3.
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Objective@#To observe the expression of integrin-linked kinase on pulmonary fibrosis of paraquat (PQ) poisoning rats, and to discuss the relationship between ILK with pulmonary fibrosis induced by paraquat.@*Methods@#Forty male Sprague-Dawley (SD) rats were randomly divided into control group and paraquat group, 20 in each group; the PQ group rats were intraperitoneally injected PQ liquid (18 mg/kg) , and the control group rats were injected the same volume of saline; 5 rats of these two groups were respectively sacrificed after 7, 14, 28, 56 days of PQ injection; according to the results of lung biopsy HE staining and Masson staining to observe the lung pathologic changes, measure the value of lung hydroxyproline and the expression of ILK.@*Results@#HE and Masson staining of lung pathological biopsy showed, the 7th day after PQ exposure lung tissue mostly had congestion, edema, inflammatory cells infiltration; the 14th inflammation reduced, fibrosis change appeared gradually; the 28th and 56th showed the lung tissue structure disorder and occurred apparent hydroproline with blue dye in pulmonary interstitium. Compared with control group in the same experiment period, the value of lung hydroxyproline in each experiment period of PQ group increased (P<0.05) , and the value of lung hydroxyproline of PQ group rose with the increasing of the time of PQ poisoning. The expression of ILK mRNA and protein in each experiment period of PQ group was higher than the control group in the same experiment period (P<0.05) ; ILK mRNA and protein of PQ group began to increase on 7 day phase, reached the highest on 28 day phase, and decreased on 56 day phase.@*Conclusion@#The expression of ILK mRNA and protein increased with the lung fibrosis progression of PQ poisoning rats, so ILK could be the key molecule target which induced pulmonary fibrosis of PQ poisoning.
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OBJECTIVE: To analyze the effect of occupational noise exposure on reproductive function in Chinese female workers.METHODS: The published literatures that showed the relationship between occupational noise exposure and female workers' reproductive function from Chinese National Knowledge Infrastructure,Wanfang Data,Chinese Biology Medicine Database and China Science and Technology Periodical Database from 1985 to 2016 were collected,screened and analyzed using bibliometric method.The Rev Man 5.2 software was used to calculate the pooled odds ratio(OR) and the 95%confidence interval(CI).RESULTS: A total of 25 original research papers were included.The occupational exposure to noise was significantly associated with abnormality of female menstrual cycle(OR = 2.26,95% CI: 1.70-3.01),dysmenorrheal(OR = 2.21,95% CI: 1.78-2.75),abnormal menstrual period(OR = 2.11,95% CI: 1.40-3.18),abnormal menstrual blood volume(OR = 1.73,95% CI: 1.34-2.23),pregnancy-induced hypertension(OR = 1.82,95% CI: 1.49-2.22),anemia in pregnancy(OR = 1.71,95% CI: 1.25-2.34),threatened abortion(OR = 1.98,95% CI: 1.23-3.20),spontaneous abortion(OR = 1.76,95% CI: 1.49-2.08),stillbirths(OR = 1.61,95% CI: 1.22-2.13),premature birth(OR = 1.57,95% CI: 1.36-1.81),neonatal low birth weight(OR = 1.66,95% CI: 1.39-1.98),and congenital malformations(OR = 1.58,95% CI: 1.10-2.27) compared with the controls(P<0.01).There was a doseresponse relationship between the above-mentioned indicators and the intensity of noise exposure.Occupational noise exposure was not associated with over-term birth(OR = 1.32,95% CI: 0.81-2.15,P>0.05) compared with the controls.CONCLUSION: Occupational noise exposure can affect the reproductive function and pregnancy outcomes of female workers.It is suggested that pregnant women should not be engaged in noise operations.
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<p><b>OBJECTIVE</b>To develop the knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups, and to provide a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect.</p><p><b>METHODS</b>The initial questionnaire which was evaluated by the experts was used to carry out a pre-survey in Guangzhou, China. The survey results were statistically analyzed by t test, identification index method, correlation analysis, and Cronbach's a coefficient method. And then the questionnaire was further modified, and the content of the questionnaire was determined finally.</p><p><b>RESULTS</b>After modification, there were 18 items on knowledge, 16 items on attitude, and 12 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for enterprise managers"; there were 19 items on knowledge, 10 items on attitude, and 11 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for workers".</p><p><b>CONCLUSION</b>The knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups is developed successfully, and it is a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect.</p>
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Humans , China , Health Knowledge, Attitudes, Practice , Occupational Diseases , Surveys and QuestionnairesABSTRACT
<p><b>OBJECTIVE</b>To investigate the occupational health condition in a shipyard in Guangzhou, China, and to provide a basis for improving the working environment.</p><p><b>METHODS</b>The monitoring data on occupational harmful factors in the workplace and the data on health examination of the workers were analyzed, and the occupational health condition in the shipyard was evaluated with the related occupational health standards.</p><p><b>RESULTS</b>Except benzene, toluene, and electromagnetic radiation, the dust (2.02%), grinding wheel dust (3.85%), wood dust (2 out of 4 workers exceeded the standard), welding fume (16.85%), manganese dioxide (17.98%), dimethylbenzene (8.00%), and noise (53.20%) were all out of limits to different degrees. The health examination results of 2450 workers in the shipyard showed that the respiratory impairment of dust-exposed workers (3.19%) and the hearing impairment of noise-exposed workers (12.21%) were comparatively severe.</p><p><b>CONCLUSION</b>The occupational health condition in this shipyard is not good. In order to protect the workers from health hazards, it is urgent and necessary to improve the working environment and strengthen the personal protective measures.</p>
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Humans , Air Pollutants , Benzene , China , Construction Industry , Dust , Noise , Occupational Diseases , Occupational Exposure , Occupational Health , Ships , Surveys and Questionnaires , Welding , WorkplaceABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of noise on the antioxidant capacity in different regions of brain tissue in guinea pigs.</p><p><b>METHODS</b>Thirty male white red-eye guinea pigs were equally and randomly divided into five groups: 1-, 3-, 7-, and 14-day groups after noise exposure and control group. The guinea pigs of the experimental groups were exposed to steady white noise with a sound pressure level at 100 dB for 8 h per day and for 2 consecutive days. The auditory brainstem response (ABR) of guinea pigs, as well as the glutathione (GSH) level, methane dicarboxylic aldehyde (MDA) level, and superoxide dismutase (SOD) activity in the cerebrum, cerebellum, and hippocampus, was determined prior to and 1, 3, 7, and 14 days after noise exposure.</p><p><b>RESULTS</b>After noise exposure, the shifts in ABR threshold of the experimental groups were significantly higher than that of the control group (P<0.05). Compared with those in the control group, the SOD activity and GSH level both significantly decreased in the cerebrum tissue of each experimental group after noise exposure (P<0.05) and MDA content significantly increased in the 1-day group (P<0.05). As for cerebellum tissue, the SOD activity and GSH level in the 7-day group were significantly lower than those in the control group (P<0.05), but there was no difference in MDA level between each experimental group and the control group (P>0.05). In comparison with those in the control group, the GSH and MDA levels in the 1-day group after noise exposure were significantly higher, and the GSH and MDA levels in the 3-day group and the MDA level in the 7-day group after noise exposure were significantly lower (all P<0.05).</p><p><b>CONCLUSION</b>Noise exposure can lead to hearing loss and affect the antioxidant capacity of brain tissue, which indicates that the improvement in antioxidant levels may alleviate noise-induced damage.</p>
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Animals , Male , Antioxidants , Chemistry , Brain , Metabolism , Brain Chemistry , Evoked Potentials, Auditory, Brain Stem , Glutathione , Chemistry , Guinea Pigs , Malondialdehyde , Chemistry , Noise , Superoxide Dismutase , ChemistryABSTRACT
<p><b>OBJECTIVE</b>To establish a rat model of 1,2-dichloroethane (DCE)-induced subacute toxic encephalopathy.</p><p><b>METHODS</b>Sixty Sprague-Dawley rats were randomly divided into five groups: negative control, positive control, low-dose DCE (1 472 mg/m(3)), middle-dose DCE (2 550 mg/m(3)), and high-dose DCE (4 418 mg/m(3)). The three DCE groups received static inhalation of DCE 6 hours a day for 6 consecutive days. The positive control group received intraperitoneal injection of lipopolysaccharide (5 mg/kg) and were sacrificed 8 hours after injection. Blood and brain tissue were collected, followed by determination of brain water content and HE staining for pathological examination of brain tissue.</p><p><b>RESULTS</b>The rats in DCE groups suffered decreased body weight with increasing DCE dose (P < 0.01), and brain water content rose with increasing DCEdose. The brain water content of middle-dose DCE group (80.09 ± 0.14%) and high-dose DCE group (80.28±0.10%) increased significantly as compared with that of the negative control group (79.46±0.23%) (P < 0.001). Optical microscopy discovered loose structure and vasodilation in the brain tissue of middle-dose DCE group, indicating obvious brain edema; the high-dose DCE group and positive control group had spongiform and vacuolated brain tissues with severe vascular dilation, indicating severe brain edema.</p><p><b>CONCLUSION</b>A rat model of subacute toxic encephalopathy induced by 1, 2-dichloroethane has been successfully established.</p>