Role of PI3K/Akt/mTOR pathway-mediated macrophage autophagy in affecting the phenotype transformation of lung fibroblasts induced by silica dust exposure / 中南大学学报(医学版)

OBJECTIVES@#The phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway is one of the main signaling pathways related to autophagy. Autophagy plays a key role in the formation of silicosis fibrosis. The phenotypic transformation of lung fibroblasts into myofibroblasts is a hallmark of the transition from the inflammatory phase to the fibrotic phase in silicosis. This study aims to investigate whether the PI3K/Akt/mTOR pathway affects the phenotypic transformation of silicosis-induced lung fibroblasts into myofibroblasts via mediating macrophage autophagy.@*METHODS@#The human monocytic leukemia cell line THP-1 cells were differentiated into macrophages by treating with 100 ng/mL of phorbol ester for 24 h. Macrophages were exposed to different concentrations (0, 25, 50, 100, 200, 400 μg/mL) and different times (0, 6, 12, 24, 48 h) of SiO2 dust suspension. The survival rate of macrophages was measured by cell counting kit-8 (CCK-8) method. Enzyme linked immunosorbent assay (ELISA) was used to measure the contents of transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) in the cell supernatant. The co-culture system of macrophages and HFL-1 cells was established by transwell. A blank control group, a SiO2 group, a LY294002 group, a SC79 group, a LY294002+SiO2 group, and a SC79+SiO2 group were set up in this experiment. Macrophages in the LY294002+SiO2 group were pretreated with LY294002 (PI3K inhibitor) for 18 hours, and macrophages in the SC79+SiO2 group were pretreated with SC79 (Akt activator) for 24 hours, and then exposed to SiO2 (100 μg/mL) dust suspension for 12 hours. The expression of microtubule-associated protein 1 light chain 3 (LC3) protein in macrophages was detected by the immunofluorescence method. The protein expressions of PI3K, Akt, mTOR, Beclin-1, LC3 in macrophages, and collagen III (Col III), α-smooth muscle actin (α-SMA), fibronectin (FN), matrix metalloproteinase-1 (MMP-1), tissue metalloproteinase inhibitor-1 (TIMP-1) in HFL-1 cells were measured by Western blotting.@*RESULTS@#After the macrophages were exposed to SiO2 dust suspension of different concentrations for 12 h, the survival rates of macrophages were gradually decreased with the increase of SiO2 concentration. Compared with the 0 μg/mL group, the survival rates of macrophages in the 100, 200, and 400 μg/mL groups were significantly decreased, and the concentrations of TGF-β1 and TNF-α in the cell supernatant were obviously increased (all P<0.05). When 100 μg/mL SiO2 dust suspension was applied to macrophages, the survival rates of macrophages were decreased with the prolonged exposure time. Compared with the 0 h group, the survival rates of macrophages were significantly decreased (all P<0.05), the concentrations of TGF-β1 and TNF-α in the cell supernatant were significantly increased, and the protein expression levels of Beclin-1 and LC3II were increased markedly in the 6, 12, 24, and 48 h groups (all P<0.05). Immunofluorescence results demonstrated that after exposure to SiO2 (100 μg/mL) dust for 12 h, LC3 exhibited punctate aggregation and significantly higher fluorescence intensity compared to the blank control group (P<0.05). Compared with the blank control group, the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were up-regulated in the SiO2 group (all P<0.05). Compared with the SiO2 group, the protein expressions of PI3K, Akt, and mTOR were down-regulated and the protein expressions of LC3II and Beclin-1 were up-regulated in macrophages (all P<0.05), the contents of TNF-α and TGF-β1 in the cell supernatant were decreased (both P<0.01), and the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were down-regulated (all P<0.05) in the LY294002+SiO2 group. Compared with the SiO2 group, the protein expressions of PI3K, Akt, and mTOR were up-regulated and the protein expressions of LC3II and Beclin-1 were down-regulated in macrophages (all P<0.05), the contents of TNF-α and TGF-β1 in the cell supernatant were increased (both P<0.01), and the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were up-regulated (all P<0.05) in the SC79+SiO2 group.@*CONCLUSIONS@#Silica dust exposure inhibits the PI3K/Akt/mTOR pathway, increases autophagy and concentration of inflammatory factors in macrophages, and promotes the phenotype transformation of HFL-1 cells into myofibroblasts. The regulation of the PI3K/Akt/mTOR pathway can affect the autophagy induction and the concentration of inflammatory factors of macrophages by silica dust exposure, and then affect the phenotype transformation of HFL-1 cells into myofibroblasts induced by silica dust exposure.

Application of two occupational health risk assessment methods for dust hazards in non-coal underground mines / 环境与职业医学

Background The mining of non-coal underground mines may come into contact with various types of dust, such as lead, zinc, copper, and non-metallic minerals. Dust of various kinds commonly exists in all aspects of mining and selection, and is one of the main occupational hazard groups in non-coal underground mines. Objective To compare the application of two risk assessment methods in the occupational health risk assessment of productive dust in non-coal underground mines, and to provide a reference for the selection of dust hazard health risk assessment methods and the management of dust hazards in non-coal mines. Methods A field investigation of the dust hazards of three typical non-coal underground mining enterprises (lead-zinc mines, copper mines, and fluorite mines) was carried out, and the comprehensive index method and the occupational health risk assessment method from the International Council on Mining and Metals (ICMM) were used to perform risk assessments. The comprehensiveindex method considers the following factors: dust monitoring data, the aerodynamic diameter of dust, hazard control measures, occupational health management, daily usage, and daily exposure time to determine exposure levels. The ICMM method determines the risk level based on the consequences caused by dust, exposure probability, exposure time, and uncertainty coefficient. Kendall consistency test was used to compare agreement between the results generated by the two methods. Results The results generated by the comprehensive index method were as follows: level 3 (medium risk) or level 4 (high risk) for silica dust or lead dust; level 1 (negligible risk) or level 2 (low risk) for other dust (dust with free SiO2 content<10% and containing lead, zinc, and copper, using other dust limit values for comparison), fluorspar mixed dust, fluorine and its compounds, zinc oxide, and copper dust. The risk levels graded by the ICMM method were as follows: level 4 (very high risk) and level 3 (high risk) for exposure to silica dust and lead dust, respectively, and level 1 (tolerable risk) or level 2 (potential risk) for exposure to other dust (dust with free SiO2 content <10% and containing lead, zinc, and copper, using other dust limit values for comparison), fluorspar mixed dust, fluorine and its compounds, zinc oxide, and copper dust. The consistency level between the results graded by the two methods was very high (Kendall W coefficient=0.974, P < 0.05). Conclusion For the occupational health risk assessment of productive dust in non-coal underground mines, the consistency level of risk assessment results between the ICMM method and the comprehensive index method is very high. The ICMM method is more convenient to operate and should be preferred in assessing health risks of dust hazard in non-coal underground mines.

The incidence of artificial stone-related silicosis among interior decoration workers in different countries / 中华劳动卫生职业病杂志

In this paper, 177 cases of artificial stone-related silicosis in interior decoration workers from Israel, Spain, USA, Italy and Australia were analyzed. Interior decoration workers were from small businesses (or workshops), engaged in kitchen and/or bathroom artificial stone countertops cutting, grinding, polishing and other reprocessing. In the working environment, the content of crystalline silica in artificial stone was more than 70%, and the concentration of silica dust exceeded the relevant standards. Most workplaces used dry cutting without ventilation and dust removal and other dust-proof measures, and most workers did not wear qualified respiratory protective equipment. Taking comprehensive measures such as wet operation, ventilation and dust removal, and individual protection can effectively prevent the occurrence of artificial stone-related silicosis.

Silicosis en el Paraguay: la amenaza no se ha ido

La literatura médica nacional guarda una asignatura pendiente relativa a las enfermedades ocupacionales. La silicosis es la neumoconiosis más frecuente y se debe a la inhalación de sílice cristalina y, acorde a la susceptibilidad individual junto a la intensidad de exposición y a la concentración del mineral en el aire, puede originar determinadas formas clínicas. La silicosis crónica es la forma más frecuente y se asocia a varios tipos de labores como cavar pozos y el trabajo en canteras. En los últimos tiempos se relatan otros oficios que pueden originar formas más aceleradas de la enfermedad en tiempos más abreviados de exposición, recrudeciendo brotes preocupantes en adultos en edad laboral. Realizamos una revisión narrativa de trabajos observacionales hechos en el Paraguay con el objetivo de analizar varios aspectos puntualizando las aristas clínicas y demográficas regionales.

Occupational diseases remain an unresolved issue in the national medical literature. The most common form of pneumoconiosis is silicosis, which is brought on by inhaling crystalline silica and depending on the susceptibility of the person, the extent of their exposure, and the concentration of the mineral in the air, silicosis can result in different clinical forms. The most prevalent type, chronic silicosis, is linked to a variety of jobs, including well digging and quarry work. In recent times, other trades have been reported that can cause more accelerated forms of the disease in shorter exposure times, worsening worrying outbreaks in working-age adults. With the intention of assessing various elements and highlighting certain clinical and regional demographic aspects, we performed a narrative review of observational studies conducted in Paraguay.

Research advances on silica dust induced-autoimmune diseases and its mechanism / 中国职业医学

Silica dust is one of the main occupational hazards in various industries. In addition to causing occupational silicosis, silica dust can also stimulate innate and acquired immunity and induce autoimmune diseases(AID) such as systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and antineutrophil cytoplasmic antibody(ANCA)-associated vasculitis. Silica dust exposure can induce changes in the levels of autoantibodies in vivo, such as rheumatoid factor, antinuclear antibody, ANCA, anti-centromere antibody, anti-topoisomerase Ⅰ antibody, anti-desmoglein antibody, anti-centromere antigens-B antibody, anti-carbamylated protein antibody, anti-smooth muscle antibody and anti-glomerular basement membrane antibody. At present, the mechanism of autoimmune disorders induced by silica dust has not yet been fully elucidated. The current research suggests that it is related to cell apoptosis of alveolar macrophages, the disorder of the Fas/Fas ligand system, the imbalance of T cell proportion, and the dysregulation of T helper cell(Th) 1 and Th2 type cytokines homeostasis. Understanding the pathogenesis of autoimmune disorders induced by silica dust and exploring possible therapeutic targets will provide new ideas for the treatment of silicosis.

Investigation on the current status of silica dust hazard in workplaces in Jiangxi Province / 中国职业医学

OBJECTIVE: To analyze the current status of silica dust hazard in workplaces of Jiangxi Province. METHODS: The level of silica dust in the air of workplaces, occupational health examination of the dust-exposed workers and diagnosis of occupational disease in 1 557 enterprises in Jiangxi Province were investigated and analyzed. RESULTS: The 1 557 enterprises were included in eight industries, and the main types of enterprises were non-coal mining, ceramic products manufacturing and stone processing industry(a total of 85.16%). There were 4 029 jobs/positions that were involved in exposure to silica dust in these workplaces. Among them, the exposure concentration of time weighted average(C_(TWA)) of total dust and respirable dust exceeded 21.52% and 20.55%, respectively. The posts where the total dust and respirable dust that exceed the standard were found in the quartz sand processing industry, non-ferrous metal smelting industry and stone processing industry, that were the top three among the eight industries(all P<0.01). Among the 828 posts with C_(TWA) of respiratory dust exceeding the standard, the C_(TWA) exceeding rate of mild-, moderate-and high-hazardous jobs were 3.87%(156/4 029), 1.66%(67/4 029) and 15.02%(605/4 029), respectively. Among 23 643 dust-exposed workers, the detection rates of occupational contraindications and suspected silicosis were 2.06% and 1.51%, and the prevalence of silicosis was 1.21%. CONCLUSION: Silica dust hazard in workplaces of quartz sand processing industry, non-ferrous metal smelting industry and stone processing industry are serious in Jiangxi Province. The supervision and management of occupational health should be further strengthened to guarantee the occupational health of workers.

Comparison of five occupational health risk assessment models applied to silica dust hazard in small open pits / 预防医学

Objective@#To quantitatively compare five occupational health risk assessment models in assessing silica dust hazard risk in small open pits, so as to provide the reference for the research of occupational health risk assessment methodology@*Methods @#Seven small open pits were selected as the evaluation sites. The models from Singapore, the United Kingdom's Control of Substances Hazardous to Health Essentials ( COSHH Essentials ), Australia, Romania, and the International Council on Mining and Metals ( ICMM ) were applied to assessing the occupational health risk of the workers exposed to silica dust. The risk ratios ( RRs ) were calculated, and the parallelism, accuracy and correlation of the evaluation results of the five models were compared. @*Results @#The RRs of the Singaporean model, COSHH model, Romanian model, Australian model and ICMM model were 0.8, 1.0, 0.4, 0.6 and 0.8, respectively. The Singaporean model and the Australian model were able to distinguish transport drivers from sprinkler drivers in the health risk exposed to silica dust, which was consistent with the actual risk of the two posts. Except for COSHH model, the RRs of the other four models were positively correlated ( P<0.05 ); the RRs were all positively correlated with concentration ratios ( CRs ) ( P<0.05 ), and the correlation coefficient between RRs and CRs of the Singaporean model was the largest (0.801).@*Conclusion @#Among the five models, the Singaporean model can more accurately evaluate the hazard risk of silica dust in posts of open pits, and has a good correlation with the other models.

Analysis of respiratory dust hazard in 20 coal mining enterprises of a mining group / 中国职业医学

OBJECTIVE: To analyze the hazardous status of respiratory dust in coal mining enterprises. METHODS: A total of 20 coal mining enterprises in a mining group were selected as the research subjects using a cluster random sampling method. Respiratory dust in the workplace was detected, and the incidence of pneumoconiosis was investigated. RESULTS: The dust types in the workplace of these 20 coal mining enterprises were mainly coal dust and silica dust. The posts with serious coal dust hazard were coal mining and tunneling posts. The M(P_0-P_(100)) of the exposure concentration of time weighted average(C_(TWA)) were 2.38(0.19-14.21) and 2.73(0.49-9.57) mg/m~3. The over-standard rate was 49.2% and 50.0%, respectively, that was higher than the post of gangue selection(all P<0.05 or all P<0.017). The results of short time exposure concentration of short term(C_(STE)) and the over-standard rate were higher in the coal mining and tunneling posts than those of gangue selection and boiler room post(all P<0.05 or all P<0.008). The most serious post with silica dust hazard was the tunneling post, and the M(P_0-P_(100))of C_(TWA) was 1.30(0.38-8.50) mg/m~3, and the over-standard rate was 85.7%. The detection results and over-standard rate of C_(STEL) were higher in the coal mining and tunneling posts than that of boiler room post(all P<0.01). The coal dust over-standard rate of C_(TWA) in workplaces of coal mining enterprises increased from 2015 to 2018(P<0.05). However, there was no significant difference in the over-standard rate of silica dust C_(TWA) in different years(P>0.05). From 2015 to 2018, the incidence of pneumoconiosis was 0.3%, 0.3%, 0.2% and 0.3% respectively, and the patients were all from coal mining and tunneling posts. CONCLUSION: The supervision, management and treatment of respiratory dust hazard in coal mining and tunneling posts should be strengthened to protect the health of workers.

Subacute dynamic silica dust inhalation induced changes of pathology and cytokines in mouse organs / 中国职业医学

OBJECTIVE: To investigate the effects of subacute dynamic silica dust inhalation on the histopathology of major organs and the cytokine changes in lung tissues. METHODS: Male Kunming specific pathogen free mice were randomly divided into control group and dust exposure groups of 3, 14 and 28 d, with 7 mice in each group.The mice of the 3 exposure groups were given for 3, 12 and 24 days with silica dust at a concentration of 1 000.00 mg/m~3 using the self-made automatic dust inhalation device, 6 hours per day and 6 days per week. Rats in the control group were not treated with dust. After the end of treatment, rats were sacrificed. The organ coefficients of the liver, kidney, spleen and lung were calculated. The pathological changes of the organs were observed by hematoxylin-eosin staining method. The pulmonary fibrosis of lung tissues was evaluated by Masson staining method. Sirius scarlet picric acid staining was used to observe the collagen fiber area ratio in lung tissues. Enzyme-linked immunosorbent assay was used to detect the levels of interleukin(IL)-1β, tumor necrosis factor(TNF)-α, transforming growth factor(TGF)-β1 and matrix metalloproteinase 2(MMP-2) in lung tissues. Colorimetric method was used to detect the level of hydroxyproline(HYP) in lung tissues. RESULTS: After the exposure to silica dust, the histology of liver, spleen and kidney tissues were not significantly changed in the mice of the 3 dust exposure groups. The lung organ coefficients increased in the mice of dust exposure groups of 3, 14 and 28 d compared with the control group(P<0.05). The spleen coefficient of mice in dust exposure groups of 3 and 14 d were higher than that in control group(P<0.05). Among the dust exposure groups, the score of pulmonary fibrosis and HYP level in lung tissues were increased with the prolonged dust exposure time(P<0.05). The collagen fiber area ratio of collagenⅠand Ⅲ, and the levels of IL-1β, TGF-β1 and MMP-2 in lung tissues increased in the 3 dust exposure groups compared with the control group(P<0.05). The collagen fiber area ratio of collagen Ⅲ, and the level of IL-1β in lung tissues of the 14 and 28 d of dust exposure group increased(P<0.05), and the TGF-β1 level decreased(P<0.05), when compared with the 3 d group. The collagen fiber area ratio of collagen Ⅰ in lung tissues of 14 d group and the level of MMP-2 in the 28 d group were higher than that of the 3 d group(P<0.05). The level of TNF-α in lung tissues of 14 d group was higher than that of the control group(P<0.05), and while in 28 d group it was lower than those of the other 3 group(P<0.05). CONCLUSION: Subacute dynamic inhalation of silica dust can cause acute lung injury in mice. There is no obvious pathological change in liver, kidney and spleen. The pathological changes of lung tissue are inflammation and fibrosis, and the degree of fibrosis increases with the extension of dust exposure time, and cytokines also changed.

Results analysis of occupational physical examination for major occupational hazards exposed laborer in 2018 in Guangzhou / 中华劳动卫生职业病杂志

Objective@#To analyze the results of occupational physical examination for major occupational hazard exposed laborer in 2018 in Guangzhou, to provide scientific basis for occupational health supervise.@*Methods@#In January 2019, descriptive epidemiological methods were used as the data sources of the Occupational Disease and Occupational Health Information Surveillance System and the report data of Guangzhou Occupational Health Inspection Agency, collecting 2733 employers from 28 Occupational Health Inspection Organizations in 11 administrative regions of Guangzhou from January to December 2018, as well as the occupational health examination data of 97688 workers exposed to the occupational-disease-risk factors, to analyze the inspection of suspected occupational diseases and contraindications during the period of work of the workers who were monitored for the occupational hazard factors (silicon dust, welding fume, benzene, lead, Ethylene Dichloride, N-hexane, high temperature and hand-transmitted vibration) .@*Results@#Total 128 cases of suspected occupational disease were detected, including 3 suspected silicosis, 8 suspected welder＇s pneumoconiosis, 17 suspected other pneumoconiosis, 10 suspected benzene poisoning, 1 suspected lead poisoning and 89 suspected noise deafness. There were 2061 cases of occupational contraindication, among which 550 cases were contraindication of high temperature, 261 cases were benzene and 1089 cases were noise.@*Conclusion@#The Occupational Health Inspection Institution of this city should continuously monitor the occupational health status of the harmful workers during their work, do a good job of prevention, and strengthen the labor protection.

Analysis of silica dust detection results in workplace air of somewhere in enterprise / 中华劳动卫生职业病杂志

Objective@#To understand the occupational hazard and distribution of silica dust (free SiO2≥10%) in the workplace environment of the enterprises in Fengxian District, and to provide scientific basis for improving the working environment and protecting the physical and mental health of the workers.@*Methods@#Individual sampling monitoring and on-site labor hygiene investigation were conducted on 421 workers involved in 87 silicon dust enterprises in the jurisdiction from 2014 to 2018, and measured concentration-time weighted average (CTWA) .@*Results@#The results showed that the range of the CTWA was (0.021~17.000) mg/m3, the median was 1.600 mg/m3, and the qualified rate of 30.88%. The difference of total dust concentration was statistically significant in different years (Z=38.831, P<0.05) . The qualified rate of small-scale enterprises is higher than that of medium-scale enterprises (χ2=9.472, P<0.05) . The qualified rate of other domestic enterprises is higher than that of private enterprises and foreign enterprises (χ2=10.089, P<0.05) . The acceptance rate of metal products manufacturing is lower than that of general equipment manufacturing and other manufacturing enterprises (χ2=64.626, P<0.05) . The qualification rate of natural ventilation is higher than that of mechanical ventilation (χ2=6.278, P<0.05) .@*Conclusion@#The enterprises involved in silicon production in Fengxian District need to further strengthen the production process reform and improve the ventilation and dust removal protection measures. Widely carry out the publicity of occupational disease prevention and control law, conduct targeted pre-job training, improve workers' awareness of self-protection, and protect the occupational health of workers in many ways.

The effects of long-term exposure to silica dust on serum CC16 and KL-6 levels / 中华劳动卫生职业病杂志

Objective@#To investigate the effects of long-term exposure to silica dust on serum CC16 and KL-6 levels.@*Methods@#The patients with stage I silicosis who were hospitalized in our hospital from April 2016 to April 2017 were treated as silicosis group. The silica dust exposed workers without silicosis who were taken the physical examination in our hospital were taken as a dust-exposed group. The healthy control group comes from in the same period of community physical examination did not touch the dust. The levels of CC16 and KL-6 in serum of all subjects were determined by enzyme-linked immunosorbent assay (ELISA) , and the levels of CC16 and KL-6 in serum were compared in three groups.@*Results@#Compared with the control group, the serum levels of CC16 in the silicosis group (P<0.01) and the dust-exposed group (P<0.01) were significantly lower. Compared with the control group, the level of serum KL-6 in the silicosis group was significantly decreased (P<0.01) compared with the control group, while the level of KL-6 in the serum of the dust-exposed group was significantly increased (P<0.01) . The ROC area of CC16 for diagnosis of silicosis was 0.92 (P<0.01) , with a sensitivity of 81.37%, specificity of 92.63% and Kappa value of 0.74.@*Conclusion@#Long-term exposure to silica dust may lead to a decrease in serum CC16 levels. Reduced serum CC16 levels may be useful in identifying the diagnosis of silicosis.

The effects of silica dust on the expression of MyD88 and TRAF6 mRNA of lung macrophages in rats / 中华劳动卫生职业病杂志

Objective@#To investigate the effects of silica dust on the expression of Myeloid differentiation factor 88 (MyD88) mRNA and tumor necrosis factor receptor-associated factor (TRAF6) mRNA of lung macrophages in rats.@*Methods@#Selecting 40 SPF-class Wistar rats with average weight (200±20) g randomly divided into control group and 30 d, 60 d, 120 d experimental groups with 10 rats in each group according to body weight. The experimental groups rats were injected with 1 ml of SiO2 (100 mg/ml) suspension through the trachea into lung only once, then they were respectively killed after 30, 60, 120 days. The control group rats were injected with 1 ml of saline into lung, and killed after 120 days. The lungs of the rats were taken for pathological observation. Lung macrophages were extracted and counted, and their activity was detected by MTT. RT-qPCR was used to assess the relative contents of MyD88 mRNA and TRAF6 mRNA.@*Results@#Silica dust inhalation led to infiltration of lung tissue cells, thickening the alveolar wall and destruction of alveolar structure. The longer the exposure to dust, the more obvious the results were. The number of macrophages in all experimental groups and activity in the 30 d, 60 d groups were significantly higher than that in the control group (P<0.05) . Among them, 30 d group had the largest number and the highest activity. Compared with the control group, the expression of MyD88 mRNA and TRAF6 mRNA of lung macrophages in rats increased in the experimental groups (P<0.05) , especially in the 60 d group.@*Conclusion@#Silica dust inhalation can increase the expression of MyD88 and TRAF6 in macrophages, suggesting that silica dust can induce silicosis fibrosis by activating TLR/NF-κB signal pathway.

Results analysis of occupational physical examination for silica dust, benzene and noise-exposed laborer in 2016 in Guangzhou City / 中华劳动卫生职业病杂志

Objective@#To analyze the results of occupational physical examination for silica dust, benzene and noise-exposed laborer in 2016 in Guangzhou, to provide basis for occupational health supervise.@*Methods@#The data were derived from "occupational disease and health information surveillance system" and the summary data reported by all the occupational physical examination agencies, and analyzed by descriptive epidemiology method.@*Results@#77506 data from 21 agencies of 12 district were collected, and 63 suspected occupational disease were detected, which including 1 silicosis, 8 benzene poisoning, 54 noise deafness.@*Conclusion@#Noise exposure was distributed widely, noise deafness had to be focused on, occupational chronic benzene poisoning and silicosis should be monitored continuously. Small, foreign economy and manufacturing industry should be supervised firstly.

Protective effect and mechanism of tHBQ on acute silica dust exposure in rats / 中华劳动卫生职业病杂志

Objective@#To study the protective effects and possible mechanisms of tBHQ in rats exposed to acute silicadust.@*Methods@#Male Wistar rats without specific pathogen SPF were randomly divided into control group、model group and intervention group, 32 rats for each group. Rats in the model group and the intervention group were treated with a single non exposed tracheal dust method to establish the rats exposed to silica model. The intervention group was intervened with 1% tBHQ solution, once a day. Each group 8 rats were sacrificed at 3,14,28,60d, respectively.The contents of IL-1,TNF-α, HYP,TGF-β in the lung tissue of rats were determined by enzyme linked immunosorbent assay(ELISA), the contents of MDA and the GSH-PX activity in lung tissue and serum of rats were determined by colorimetry.@*Results@#Compared with the control group, the contents of IL-1 in the lung tissue of the model group and the intervention group at each time point increased with time, the contents of IL-1 of model group reached the maximum at 60d, the contents of IL-1 in intervention group reached the maximum at 28d(P<0.05), except 3 d. Compared with the control group, the contents of TGF-β and HYP in the lung tissue of the model group and the intervention group at 28 and 60 d increased with time and reached the maximum at 60d(P<0.05). Compared with the model group at each time point, the contents of IL-1, TGF-β, HYP in the intervention group were lower than those in the model group(P<0.05). Compared with the control group, the contents of MDA in lung tissue and serum of rats in model group and intervention group at different time points increased with time(P<0.05). Compared with the control group,the activity of GSH-PX in serum and lung tissue of rats in model group and intervention group decreased with time,there was no significant difference in 3d(P<0.05), compared with the control group, the activity of GSH-PX in the lung and serum tissue of in-tervenetion group was higher than model group except the 3d(P<0.05).@*Conclusion@#The intervention of tBHQ can alleviate oxidative stress in rats exposed to silica dust to some extent, improve the antioxidant capacity of the body, and reduce the contents of IL-1, TNF-α, TGF-β,HYP in lung tissue,it has acertain impediment and inhibition effect on the inflammation and fibrosis caused by acute silica dust exposure.

The tuberculosis prevalence and risk factors among silicotic patients / 中华传染病杂志

Objective To investigate the prevalence of tuberculosis among silicosis patients and silica exposure patients,and to analysis the risk factors of tuberculosis among these population.Methods A total of 1 227 silica exposure patients from Wenling,Zhejiang were enrolled in this field study.Basic demographic information was collected and chest X-ray was taken for each patient.Sputum was collected for Mycobacterium tuberculosis culture and strain identification. In univariate analysis,t test was performed for continuous variables andχ2 test for categorical variables.In multivariate analysis,the odds ratio (OR )was calculated along with a 95 % confidence interval (CI )by binary Logistic regression. Results A total of 1 204 silica exposure patients had full basic information and 99.8% were male patients with mean age of (59.4 ± 6.8 )years.The patients in phase 0 + to phase Ⅲ were 172 (14.3%),255 (21 .2%),160 (13.3%)and 617 (51 .2%),respectively.The tuberculosis prevalence rate was about 7.3% among these population.The risk factors for tuberculosis including phase Ⅱ silicosis (OR =2.96, 95 %CI :1 .05 -8.32,P =0.04)and phase Ⅲ silicosis (OR=3.88,95 %CI :1 .58-9.56,P <0.01),and contacting with tuberculosis patients (OR=4.14,95 %CI :1 .91 -8.98,P <0.01).Patients complicated with tuberculosis lacked specific symptoms,but fever and weight loss were more frequent.Conclusion Tuberculosis is highly prevalent in silicotic patients,especially in patients with phase Ⅱ/Ⅲ silicosis and in patients with tuberculosis contact history.

Effect of Miao Nationality Herbs Spray for Serum SOD, MDA and Expression of Fas-mRNA and Caspase-3 mRNA in Lung Tissues of Silica-treated Rats / 世界科学技术-中医药现代化

This study was aimed to prepare the spraying agent of prescriptions of Miao nationality herb and investigate the effect of Miao nationality herbs spray for serum SOD, MDA, and expression of Fas and Caspase-3 mRNA in lung tissues of silica-treated rats. The healthy SD rats were divided into 5 groups. Silica dust suspension was used in the model establishment of 4 groups. After the model was successfully established, 3 groups were randomly selected and given glucocorticoids atomization inhalation, Miao nationality herbs spray, Miao nationality herbs spray combined with intragastric administration of herbal medicine, respectively. After 40-day treatment, water-solubletetrazolium salt (WST-1) was used in the detection of serum superoxide dismutase (SOD). Thiobarbituric acid (TBA) was used in the detection of malondialdehyde (MDA). The mRNA expression variance of the Fas and Caspase-3 were detected by RT-PCR. The results showed that compared with the silica dust suspension group, the SOD activity of serum in the Miao nationality herbs spray group was significantly increased (P< 0.05). MDA content and the mRNA of Fas and Caspase-3 were significantly lower in the Miao nationality herbs spray group (P< 0.05). It was concluded that Miao nationality herbs spray group was able to increase the SOD activity of serum, decrease MDA content, and obviously decrease the expression of Fas and Caspase-3 of lung tissues among silica dust suspension rats.

A Case of Silicosis and Pneumothorax in a Workplace Producing Dental Porcerlain / 대한산업의학회지

BACKGROUND: Silicosis is more likely to occur in people working in the mining industry. However, workers suffering from silicosis have recently been reported frequently in other areas. We present a case of silicosis occuring in a 43-year-old man who had worked for 20 years in a workplace producing dental porcelain. CASE: The man was admitted to the emergency room with acute chest pain caused by pneumothorax. Chest X-ray indicated numerous small opacities spread over the whole lung field and a large opacity in the right middle lung field. According to ILO classification, the shape of the small opacities was t/s, the profusion rate was 2/3 and the large opacity was classified into the B category. Following this diagnosis of silicosis, the patient's medical history and work exposure history were examined. According to his medical history, he had undergone closed thoracostomy in 2006 because he had suffered pneumothorax twice (in 2005 and 2006) and his smoking history was 7 pack years. In particular, he had been exposed to silica dust for 20 years in his workplace. CONCLUSION: Despite the absence of any specific risk factor that caused pneumothorax, the patient suffered this condition three times. All clinical results and the progress of his physical symptoms, including radiologic findings from chest X-ray and computed tomography, clearly supported the diagnosis of silicosis. Except for exposure to silica dust in the workplace, no other risk factors causing silicosis were found. Therefore, he was finally diagnosed as having silicosis caused by exposure to silica dust in the workplace and followed by pneumothorax.

The Effect of Silica Dust on Ventilatory Function in Foundry Workers / 대한산업의학회지

In order to study the exposure level of silica dust and the effects of silica dust on ventilatory function, respirable dust samples were collected by personal air samplers using NIOSH method 0500 from the selected foundry operations, and ventilatory function tests were performed on 209 male foundry workers and 239 male control subjects. Ventilatory indices such as forced vital capacity (FVC) , one-second forced expiratory volume (FEV1), ratio of FEV1 to FVC(FEV1 %), maximal mid-expiratory flow(MMF), peak expiratory flow rate (PEFR) and maximal expiratory flow at 25, 50 and 75 % of expired FVC (FEF25, FEF50, FEF75 were obtained by analyzing forced expiratory spirogram and maximal expiratory flow-volume curve which were simultaneously measured by Vitalography in standing position. The results were as follows : 1. The average quartz concentrations of respirable dust were the highest in melting operation (0.079 mg/m3) and followed by molding operation (0.051 mg/m3), finishing operation (0.041 mg/m3) and coremaking operation (0.023 mg/m3) in the descending order. 2. No significant differences for mean values of all ventilatory indices expressed as percent of predicted value were demonstrated between smokers and nonsmokers In foundry workers and control subjects. 3. Mean values of all ventilatory indices except FVC of foundry workers were significantly lower than those of control subjects. 4. Mean values of FEV1 %, MMF, FEF25, FEF50 and FEF75 expressed as percent of predicted value tended to decrease with increasing cumulative dust exposure. 5. In foundry workers, proportions of workers with low MMF, FEF50 and FEF75 were markedly higher than those with other indices, and were significantly increased with increasing cumulative dust exposure. 6. In foundry workers, 2 workers(1.0 %) were diagnosed as silicosis and the profusion of radiographic opacities were category 1/0 and q type. With the above considerations in mind, it suggested that increasing exposure of silica dust be associated with progressive deterioration in ventilatory function of an obstructive nature and that MMF, FEF50 and FEF75 be more sensitive indices in the detection of the early obstructive changes of air flow of workers exposed to silica dust.