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Background The exposure to diesel particulate matter (DPM) and its polycyclic aromatic hydrocarbons (PAH) is closely related to the morbidity and mortality of ischemic heart disease (IHD). However, it is unclear what key components and targets of DPM exposure involve in myocardial ischemia-hypoxia injury and associated mechanisms. Objective To identify key PAH components of DPM that act on myocardial hypoxic injury, andclarify the role of oxygen sensors-regulated anaerobic metabolism in DPM and key components-induced hypoxic injury and the targets of the key PAH components. Methods Human cardiomyocyte cell line AC16 cells were exposed to 0, 1, 5, and 10 μg·mL−1 DPM in a high glucose DMEM medium with 10% fetal bovine serum (FBS) (HGM) or low FBS (0.5%) in high glucose DMEM medium (LFM), for 12 h under 2% O2, and expression of hypoxia-inducible factor-1α (HIF-1α), Bax, and Cleaved-caspase3 was determined by Western blotting. Under normal condition, the cell viability was detected after PAH exposure for 12 h. Under the condition of ischemia-hypoxia model, cells were exposed to 0, 0.005, 0.5, and 5 µg·mL−1 PAH for 12 h, and the protein expression of HIF-1α, Bax, and Cleaved-caspase3 was determined. After exposure to DPM or PAH for 12 h, the contents of pyruvate and lactate in cells were detected. Pretreatment with glycolysis inhibitor GSK2837808A was used to explore the role of glycolysis in DPM and benzo[a]pyrene (BaP)-induced hypoxia injury. A molecular docking technique was used to analyze the binding affinity between PAH and oxygen sensors (prolyl hydroxylase domain-containing protein 2, PHD2, and factor-inhibiting hypoxia-inducible factor 1, FIH1), and the protein levels of PHD2, FIH1, and hydroxyl-HIF-1-alpha (OH-HIF-1α) after the DPM or BaP treatment were further determined. Results Under hypoxia, DPM exposure in the LFM induced the expression of HIF-1α, Bax, and Cleaved-caspase3 (P<0.01). Therefore, hypoxia and LFM were selected as the basic ischemia and hypoxia condition. Except for anthracene (Ant) (P>0.05), other PAH decreased cell viability when the concentration was above 1 μg·mL−1 (P<0.05). All concentrations of BaP induced the expression of HIF-1α protein (P<0.05), and the protein levels of Bax and Cleaved-caspase3 were up-regulated after the 0.5 and 5 µg·mL−1 BaP exposure (P<0.01). After exposure to DPM (1, 5 and 10 μg·mL−1) or BaP (0.5 and 5 μg·mL−1), the intracellular pyruvate and lactate contents increased (P<0.05). The glycolysis inhibitor co-treatment decreased the levels of HIF-1α, Bax, and Cleaved-caspase3 proteins compared with the DPM or BaP exposure group for 12 h (P＜0.05). The binding abilities of the five PAHs to the oxygen sensors PHD2 and FIH1 were strong, and BaP was the strongest. Although the DPM or BaP exposure had no effects on the protein levels of PHD2 and FIH1 in AC16 cells (P＜0.05), the protein level of OH-HIF-1α was decreased (P＜0.01). Conclusion BaP exposure can promote hypoxia and injury of myocardial cells and is the key PAH component of DPM that induces myocardial ischemia and hypoxia injury. BaP exposure inhibits the hydroxylation function of PHD2 on HIF-1α by combining with PHD2, decreases the level of OH-HIF-1α and induces HIF-1α accumulation. And then HIF-1α promotes anaerobic metabolism and accelerates ischemia and hypoxia injury of myocardial cells.
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The air pollution related health hazards have been a major public health issue for a long time. As an important source of air pollution, diesel exhaust (DE) exposure associates with serious adverse health outcomes. Apart from the exposure in general population, extensive occupational DE exposure populations are reported in many industries, such as transportation, mining, shipping, and construction. Therefore, the studies for internal exposure levels, biomarkers, and toxic mechanisms of DE in occupational population are critical for protecting human from DE-posed health hazards. This special column published some novel findings involving DE exposure (internal & external exposure level), multiple biological effects, toxicity mechanisms, key molecular events, and crucial biomarkers. These studies will provide scientific data for controlling DE associated occupational health hazards, formulating effective DE pollution control strategies, and provide a new scientific perspective and evidence for health risk assessment and prevention.
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Polyhexamethylene guanidine (PHMG) is a high molecular guanidine compound with a broad spectrum of antibacterial effects. Since the outbreak of the 'humidifier disinfectant-induced lung injury’ event in South Korea, the respiratory toxicity of PHMG had become a public concern. An epidemiological survey in Korea found that PHMG-containing disinfectants were an important risk factor for pulmonary fibrosis. Animal experiments also showed that the exposure to PHMG through the respiratory tract could cause irreversible fibrosis in the lungs. TGF-β signaling pathway, epithelial-mesenchymal transition and pulmonary inflammation might be the main pathways that could mediate PHMG-induced pulmonary fibrosis. This article provided an overview of the characteristics of population exposure to PHMG and research progress in the field of respiratory toxicology and recommendations for the rational and standard of using PHMG-related products in China.
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Objective@#To explore the lung damage caused by repeated inhalation of polyhexamethyleneguanidine (PHMG) disinfectant aerosol and the corresponding toxicological characteristics.@*Methods@#Thirty four-week-old mice of C57BL/6N strain were randomly divided into three groups, the control group, low-dose group, and high-dose group. Each group had 5 male mice and 5 female mice. Lab II-level purified water was used in the control group. The PHMG disinfectant aerosol was generated by using the ultrasonic atomization of the aqueous solution containing PHMG. The PHMG concentrations in the low-and high-dose groups were 0.1 mg/ml (0.01%) and 1 mg/ml (0.1%), respectively. The concentration of PHMG in the post-chemical exposure room was 1.03 mg/m3 and 9.09 mg/m3 according to the air sampler analysis. The experimental mice were exposed to the PHMG in dynamic respiratory exposure mode for 4 hours every day in 21 days. After 21-day exposure, bronchia alveolus lung fluids (BALFs) were used to evaluate the inflammatory cells in the lungs, and pathological evaluation, special staining and immunohistochemical methods were further performed to evaluate the key indicators of pulmonary fibrosis.@*Results@#Compared to the control group, the body weight of mice in the high-dose group was significantly decreased (P<0.05), while that of mice in the low-dose group did not significantly differ (P>0.05). The number of inflammatory cells in BALFs of low-dose exposed mice was slightly reduced, and the lung tissue pathology began to show lung damage with early fibrosis symptoms (P<0.05). The pathological examination of mice in the high-dose group showed changes in pulmonary fibrosis. Immunohistochemical staining showed that pulmonary fibrosis marker, α-SMA, was significantly increased in low-dose group and high-dose group (P<0.05).@*Conclusion@#The repeated inhalation of PHMG disinfectant could cause lung damage such as pulmonary fibrosis in mice. It could suggest that special warnings should be given to this common disinfectant and respiratory protection measures should be adopted during industrial production and daily use.
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Dioxins, polybrominated diphenyl ethers, and benzo(a)pyrene are common organic pollutants in food. They have been of concern to academics and government administrations due to high residue and persistence, easy accumulation and strong harmful effects. The National Research Council of the United States of America published Toxicity Testing in the 21st Century: A Vision and Strategy in 2007, which proposed a new concept of toxicity testing that toxicity testing should take full consideration of population exposure data and base on in vitro tests, human cell lines, toxicity pathways and high-throughput screening. Meanwhile, systems biology, bioinformatics and rapid assay technologies will be used to better understand toxicity pathways—the cellular response pathways that can lead to adverse health effects when sufficient perturbing induced by chemicals exposure. The new toxicity testing strategy has changed the traditional testing pattern and has brought a wide impact on the international relevant fields. The European Union, the World Health Organization, and the United States Environmental Protection Agency, the Food and Drug Administration, and the National Center for Toxicological Research have organized relevant discussions and exploratory studies to address the new toxicity testing concept and how to evaluate and utilize the results of traditional toxicity test researches. Compared to the discussion, 'whether to do it’, ten years ago, the question, 'how to do it’, has become the concern of the current discussion. Therefore, how to respond to the concept of toxicity testing and how to effectively utilize and excavate traditional toxicity test data have been the focus of multi-disciplines and interdisciplinary academia such as toxicology, food hygiene and environmental science. Therefore, this article provides an overview of the exposure levels of dioxin, polybrominated diphenyl ethers and benzo[a]pyrene, which are typical persistent organic pollutants in food in China and the current research status of toxic pathways based on whole animal experiments. The exposure level, toxic effect and toxicity mechanism of three contaminants are analyzed and summarized in order to provide basis for future results based on the 21st century toxicity test compared with traditional tests and data mining analysis of these two kinds of data. Meanwhile, it also lays the foundation for the establishment of a toxicity testing framework based on exposure characteristics, toxic pathways, and biomarkers.
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The safety assessment of nanomaterials in food is essential for safeguarding supervision and maintaining public health. However, there are still no safety assessment procedures for nanomaterials established in national-level in China and no specific toxicology and safety assessment procedures about nanomaterials for food, too. These factors lead to restriction on food safety protection and supervision. Current methods of evaluating the safety of nanomaterials mainly rely on traditional toxicological assessment that are extrapolated based on animal experiment from high doses to low doses and from animals to humans. These uncertainties restrict the accuracy of safety assessment for nanomaterials and also limit the development of scientific and effective evaluation procedures and regulatory measures. Currently, the key issues need to be solved including exposure assessment and evaluation methods of nanomaterials in food and the established methods of the toxicity test for nanomaterials that are consistent with the objectives of toxicity test in the 21st century vision and strategy. In this article, we reviewed current administrative regulatory, situations, and existing issues of food nanomaterials either in China or some developed countries in order to provide a scientific basis in establishing safety assessment procedures for nanomaterials in food in the future.
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Objective To preliminarily evaluate the effect of glycyrrhetinic acid on the proliferation and apoptosis of keratinocytes in patients with psoriasis,and to explore its possible mechanisms.Methods Keratinocytes were isolated from patients with psoriasis,and subjected to a primary culture in vitro.After 2-3 passages,the keratinocytes were divided into several groups to be treated with glycyrrhetinic acid at final concentrations of 0 (control group),1,2,4,8 and 10 mg/L (glycyrrhetinic acid groups),respectively.After 24-72 hours of treatment,MTS assay was performed to evaluate the effect of glycyrrhetinic acid on the proliferation of keratinocytes,and flow cytometry was conducted to detect the apoptosis of keratinocytes after 24-hour treatment with glycyrrhetinic acid at different concentrations.Real-time fluorescence-based PCR was performed to determine the expression of miR-21 in keratinocytes.Results After 24-72 hours of treatment with 1-10 mg/L glycyrrhetinic acid,the proliferation activity of keratinocytes significantly decreased along with the increase in the treatment duration and concentrations of glycyrrhizinic acid.After 24-hour treatment with 1,2,4,8,10 mg/L glycyrrhetinic acid,the apoptosis rates of keratinocytes increased to (9.64 ± 0.86)％,(25.24 ± 2.93)％,(27.68 ± 3.70)％,(35.55 ± 4.23)％ and (38.89 ± 2.31)％ respectively.As LSD-t test showed,the apoptosis rates of keratinocytes were significantly higher in all the glycyrrhetinic acid groups than in the control group (10.09％ ± 0.69％,all P ＜ 0.01),except the 1 mg/L glycyrrhetinic acid group.After 24-hour treatment with 1,2 and 4 mg/L glycyrrhetinic acid,the miR-21 expression (2-△△Ct) significantly decreased (0.24 ± 0.04,0.22 ± 0.07,0.17 ± 0.05,respectively) compared with the control group (0.92 ± 0.12,F =213.10,P ＜ 0.05).After 18-,24-and 48-hour treatment with 2 mg/L glycyrrhetinic acid,the miR-21 expression significantly decreased (0.55 ± 0.02,0.22 ± 0.06 and 0.15 ± 0.06 respectively) compared with the control group (0.98 ± 0.02,F =238.10,P ＜ 0.05).Conclusion Glycyrrhetinic acid can inhibit the proliferation of keratinocytes from psoriatic patients,but promote the apoptosis,likely by down-regulation of miR-21 expression.
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Objective@#To investigate the association between etheno-DNA adduct and the promoter of DNA methylation levels of cyclin dependent kinase inhibitor 2A (P16), Ras association domain family 1 (RASSF1A) and O-6-methylguanine-DNA methyltransferase (MGMT) in workers with occupational exposure to diesel engine exhaust (DEE).@*Methods@#We recruited 124 diesel engine testing workers as DEE exposure group and 112 water pump operator in the same area as control group in Henan province in 2012 using cluster sampling. The demographic data were obtained by questionnaire survey; urine after work and venous blood samples were collected from each subject. The urinary etheno-DNA adducts were detected using UPLC-MS/MS, including 1,N6-etheno-2'-deoxyadenosine (εdA) and 3,N4-etheno-2'-deoxycytidine(εdC). The DNA methylation levels of P16, RASSF1A, and MGMT were evaluated using bisulfite-pyrosequencing assay. The percentage of methylation was expressed as the 5-methylcytosine (5mC) over the sum of cytosines (%5mC). Spearman correlation and multiple linear regression were applied to analyze the association between etheno-DNA adducts and DNA methylation of P16, RASSF1A, and MGMT.@*Results@#The median (P25-P75) of urinary εdA level was 230.00 (98.04-470.91) pmol/g creatinine in DEE exposure group, and 102.10 (49.95-194.48) creatinine in control group. The level of εdA was higher in DEE exposure group than control group (P<0.001). DNA methylation levels of P16, RASSF1A and MGMT were 2.04±0.41, 2.19 (1.94-2.51), 2.22 (1.94-2.46)%5mC in exposure group, and 2.19±0.40, 2.41 (2.11-2.67), 2.44 (2.15-2.91)%5mC in control group. DNA methylation levels were lower in exposure group (P values were 0.005, 0.002 and 0.001, respectively). Spearman correlation analysis showed that DNA methylation levels of P16, RASSF1A, and MGMT were negative associated with urinary εdA level (r values were -0.155, -0.137, and -0.198, respectively, P<0.05). No significant correlation was observed between the εdC level and any measured DNA methylation levels (P>0.05) . Multiple linear regression confirmed the negative correlation between εdA and DNA methylation levels of P16, RASSF1A, and MGMT in non-smoking group (β (95%CI) was -0.068 (-0.132--0.003), -0.082 (-0.159--0.004) and -0.048 (-0.090--0.007), P values were 0.039, 0.039 and 0.024, respectively). Moreover, εdC was negative associated with DNA methylation level of MGMT in non-smoking group (β (95%CI) was -0.094 (-0.179--0.008), P=0.032).@*Conclusion@#DEE exposure could induce the increased of εdA and decreased of DNA methylation levels of P16, RASSF1A and MGMT.
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Objective@#To evaluate the viability of gasoline engine exhaust (GEE) with different particle sizes on human lung cell line BEAS-2B in vitro by air-liquid interface (ALI) .@*Methods@#GEE were collected with a Tedlar bag and their particulate matter (PM) number, surface and mass concentration in three kind of GEE (filtered automobile exhaust, non-filtered automobile exhaust and motorcycle exhaust without three-way catalytic converter) were measured by two type of particle size spectrometer including TSI-3321 and SMPS-3938. Five groups were included, which divided into blank control group, clean air group, filtered automobile exhaust group, non-filtered automobile exhaust group and motorcycle exhaust without three-way catalytic converter group. Except the blank control group, BEAS-2B cells, cultured on the surface of Transwells, were treated with clean air or GEE by ALI method at a flow rate of 25 ml/min, 37 ℃ for 60 min in vitro. CCK-8 cytotoxicity test kit was used to determine the cell relative viability of BEAS-2B cells.@*Results@#In the filtered automobile exhaust, non-filtered automobile exhaust and motorcycle exhaust without three-way catalytic converter, high concentrations of fine particles can be detected, but the coarse particles only accounted for a small proportion, and the sequence of PM concentration was motorcycle exhaust without three-way catalytic converter group> non-filtered automobile exhaust group> filtered automobile exhaust group (P<0.001) . Compared with the clean air group, the cell relative viability in the 3 GEE-exposed groups were significantly lower (P<0.001) . Among the comparisons of GEE exposure groups with different particle size spectra, the sequence of the cell relative viability was filtered automobile exhaust group >non-filtered automobile exhaust group> motorcycle exhaust without three-way catalytic converter group (P<0.001) . When took the clean air control group as a reference, the mean of the cell relative viability in the filtered automobile exhaust group, non-filtered automobile exhaust group and motorcycle exhaust without three-way catalytic converter group, was decreased by 26.34%, 36.00% and 49.59%, respectively.@*Conclusion@#GEE with different particle size spectra could induce different levels of toxic effects to the human lung cells BEAS-2B by ALI. After lowering the concentration of particles in the GEE and using the three-way catalytic converter could obviously improve the survival rate of lung cells.
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Objective@#To explore the relationship between mitochondrial 12 S rRNA gene variation, tRNA gene variation and cytochrome oxidase Ⅱ gene point mutations and the risk of noise-induced hearing loss (NIHL).@*Methods@#A nested case-control study was performed that followed a cohort of 7 445 noise-exposed workers in a steel factory in Henan province, China, from January 1, 2006 to December 31, 2015. Subjects whose average hearing threshold was more than 40 dB(A) in high frequency were defined as the case group, and subjects whose average hearing threshold was less than 35 dB(A) in high frequency and less than 25 dB (A) in speech frequency were defined as the control group. Subjects was recruited into the case group (n=286) and the control group (n=286) according to gender, age, job category and time of exposure to noise, and a 1∶1 case-control study was carried out. We genotyped eight single nucleotide polymorphisms in the mitochondrial 12 S rRNA gene, the mitochondrial tRNA gene and the mitochondrial cytochrome oxidase Ⅱ gene using SNPscan high-throughput genotyping technology from the recruited subjects. The relationship between polymorphic sites and NIHL, adjusted for covariates, was analyzed using conditional logistic regression analysis, as were the subgroup data.@*Results@#The average age of the recruited subjects was (40.3±8.1) years and the length of service exposure to noise was (18.6±8.9) years. The range of noise exposed levels and cumulative noise exposure (CNE) was 80.1- 93.4 dB (A) and 86.8- 107.9 dB (A) · year, respectively. For workers exposed to noise at a CNE level<98 dB (A) · year, smokers showed an increased risk of NIHL of 1.88 (1.16-3.05) compared with non-smokers; for workers exposed to noise at a CNE level ≥98 dB(A) · year, smokers showed an increased risk of NIHL of 2.53 (1.49- 4.30) compared with non-smokers. For workers exposed to noise at a CNE level<98 dB (A) · year, the results of univariate analysis and multifactor analysis, adjusted by smoking and CNE, suggested that the risk of NIHL in workers exposed to noise carrying the GG genotype (G827A) was lower than that of NIHL workers exposed to noise carrying the AA genotype (G827A) [OR (95% CI) were 0.18 (0.04- 0.82) and 0.19 (0.04- 0.88), respectively].@*Conclusion@#Smoking increased the risk of NIHL in the present study. For workers subjected to a CNE<98 dB(A)·year, the mitochondrial genetic variant G827A was found to be significantly associated with the risk of NIHL.
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Objective@#To identify the association between genetic polymorphisms in the eye absent homolog 4 (EYA4) gene and noise-induced hearing loss (NIHL).@*Method@#A nested case control study was conducted based on a cohort of noise-exposed subjects. In total, 292 cases were selected from a steel factory from 6 297 subjects during Jan 1, 2006 to Dec 12, 2015,who had an average hearing threshold of more than 40 dB(A); 584 matched control subjects for each case were designated on the basis of matched criteria including same gender, age (±5 years) and duration of exposure to noise (±2 years). What's more, the control group had an average hearing threshold of less than 35 dB(A) in high frequency and less than 25 dB(A) in speech frequency. Four single nucleotide polymorphisms (SNPs) of the EYA4 gene were genotyped using a SNPscanTM multiplex SNP genotyping kit. Hardy-Weinberg equilibrium tests were performed using a χ2 test for goodness-of-fit for each SNP among the control group, and the effects of genotypes of the EYA4 gene on NIHL were analyzed by logistic regression. The haplotypes were established and their frequencies in the two groups were assessed using Haploview 4.2 and Phase 2.1 software, and interactive effects between haplotypes and cumulative noise exposure were analyzed.@*Results@#The average age of the subjects was (40.1±8.4) years and the average number of noise-exposed working years was 20.3 (8.4, 27.3) years. The range of noise exposure levels and the cumulative noise exposure were 80.2- 98.8 dB (A) and 86.6- 111.2 dB(A) · year, respectively. After adjustment for covariates including height, blood pressure, drinking status and smoking status, in the noise intensity>85 dB (A) group, subjects carrying the rs3813346 TT genotype had a higher NIHL risk than those carrying the GG genotype, and the adjusted OR (95% CI) value was 2.12 (1.21- 3.69). In the cumulative noise exposure>98 dB (A) · year group, compared with haplotype TGC, haplotype CGT showed a protective effect in the development of NIHL, with an adjusted OR (95% CI) value of 0.60 (0.37-0.97), however, the significance of intercation between EY4 gene of noise was lost after Bonferroni correction.@*Conclusion@#Genetic polymorphism in the EYA4 gene may be a genetic susceptibility factor for NIHL.
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Objective@#The aim of this study was to investigate whether genetic variability in the protocadherin 15 (PCDH15) gene may correspond with increased susceptibility to noise-induced hearing loss (NIHL) in a Chinese population.@*Methods@#A nested case-control study was performed that followed a cohort of 7 445 noise-exposed workers in a steel factory of Henan province in China from January 1, 2006 to December 31, 2015. In this study, 394 cases who had an average hearing threshold of more than 40 dB (A) in high frequency were defined as the case group, and 721 controls who had an average hearing threshold of less than 35 dB (A) in high frequency and less than 25 dB (A) in speech frequency were defined as the control group. A questionnaire was completed by participants and a physical test was also conducted. SNP genotyping was performed using the SNPscanTM Kit. Multivariate unconditional logistic regression additive models were used to analyze the genotypes in different groups, and the association with NIHL. Unconditional logistic regression models were used to assess the associations between the genotypes and NIHL.@*Results@#The average age of study participants was (40.5±8.3) years and the median number of noise-exposed working years M (P25, P75) was 21.1 (9.1, 27.3). The range of noise exposed levels and the levels of cumulative noise exposure (CNE) were 80.1- 98.8 dB(A) and 86.6- 111.2 dB(A), respectively. Only the distribution of the genotypes (TT/CC/CT) of rs11004085 in the PCDH15 gene showed a significant difference between the case and control groups (P=0.049). In the case group, the distribution was 370 (93.9%), 24 (6.1%) and 0; in the control group, the distribution was 694 (96.3%), 23 (3.2%) and 1 (0.1% ). After smoking, drinking, hypertension, height and CNE adjustment, compared with the TT genotype individuals with the CC/CT genotype had a 1.90-fold increased risk of NIHL (95% CI: 1.06- 3.40). After stratified these data by the noise exposure level or CNE when the noise exposure level was>85 dB (A), compared with cases with the AA genotype of rs10825113, individuals with the GA/GG genotype had a 2.63-fold increased risk of NIHL (95% CI: 1.12- 6.14). When the CNE was ≤ 98 dB(A), compared with cases with the TT genotype of rs11004085, individuals with the CC/CT genotype had a 2.96-fold increased risk of NIHL (95% CI: 1.33- 6.56). However, these differences were not significant after Bonferroni correction had been applied.@*Conclusions@#The results confirmed that genetic variation within the PCDH15 gene may affect the susceptibility to NIHL.
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Objective@#To analyze the incidence rate of occupational noise-induced hearing loss in noise-exposed workers in an iron and steel plant from 2006 to 2015.@*Methods@#Using a cohort study method, workers exposed to occupational noise from Jan 1, 2006 to Dec 12, 2015 were followed up and the pure tone hearing test was conducted. In total, 6 297 subjects completed two or more physical checks and the pure tone hearing test and were included in the analysis. The noise exposure level at the workplace and the equivalent continuous A-weighted sound pressure level for workers was monitored and the cumulative noise exposure dose was evaluated. The subjects were divided into low, middle and high exposure groups according to the noise exposure level, and the equivalent continuous A-weighted sound pressure level for 8 hours for each group was 80.6-85.0, 85.1-90.0 and 90.1-103.4 dB (A), respectively. While the RR and 95% CI were derived from unconditional logistic regression models. In logistic regression analysis, confounding factors such as age, gender, smoking habit, drinking habit, high temperature exposure and chemical hazards exposure level were controlled.@*Results@#During the follow-up period, 392 cases of occupational noise-induced hearing loss were diagnosed among the 6 297 subjects, with an incidence rate of 6.23%; 318 cases of high-frequency hearing loss were diagnosed, with an incidence rate of 5.05%; and 74 cases of occupational noise-induced deafness were diagnosed, with an incidence rate of 1.18% . The incidence rates of hearing loss among the high, medium and low exposure groups were 9.22% (158/1 737), 6.49% (204/3 142) and 2.08% (30/1 442), respectively; the rates of high-frequency hearing loss were 7.41% (127/1 737), 5.25% (165/3 142) and 1.80% (26/1 442), respectively; and the rates of occupational noise-induced deafness were 1.81% (31/1 737), 1.24% (39/3 142) and 0.28% (4/1 442), respectively. For the groups corresponding to cumulative noise exposure doses of ≤84.99, 85.00- 87.99, 88.00- 90.99, 91.00- 93.99, 94.00- 96.99, 97.00- 100.99, 101.00- 102.99 and ≥103.00 dB (A) · year, the incidence rates of hearing loss were 0 (0/185), 1.22% (2/164), 2.52% (17/674), 3.83% (35/913), 5.80% (106/1 827), 6.02% (67/1 113), 9.20% (95/1 003) and 18.04% (70/388), respectively. Compared with the low exposure group, the RR of hearing loss, high-frequency hearing loss and occupational noise-induced deafness for the high exposure group were 4.78 (95% CI: 3.22- 7.11), 4.36 (95% CI: 2.84- 6.69) and 6.63 (95% CI: 2.33- 18.82), respectively; and for the medium exposure group were 3.27 (95% CI: 2.22-4.82), 3.02 (95% CI: 1.99-4.59) and 4.52 (95% CI: 1.61-12.67), respectively.@*Conclusion@#The incidence rate of hearing loss for workers exposed to noise in an iron and steel plant was related to the cumulative noise exposure dose, gender, age, educational level, smoking habits, drinking habits and exposure to high temperature.
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OBJECTIVE To establish an in vitro test method and to evaluate the genotoxicity of chemicals using primary cultured mouse hepatocytes and the changes in phosphorylated histone H2AX(γH2AX)expression levels to provide a more reliable marker of the identification of genotoxicity. METHODS Hepatocytes were isolated from BALB/c mice by an improved two-step collagenase diges?tion method and then cultured in sandwich configuration. The primary cultured hepatocytes were treat?ed with various concentrations of four known genotoxic agents bleomycin(BLM),benzo(a)pyrene〔B (a)p〕,styrene and styrene-7,8-oxide(SO)within the range of 40 μmol · L-1 and two non-genotoxic agents azathioprine(Aza)and ciclosporin A(CsA)at different time points within 24 h. The cytotoxicity induced by these toxicants was assessed by CCK-8 assay. Then,the changes in γH2AX expression levels in treated cells were determined by flow cytometry. RESULTS The four genotoxic agents could be detected and two non-genotoxic agents could not be detected by this method. The γH2AX expression level was the highest when hepatocytes were exposed to BLM and SO for 3 h,or B(a)p and styrene for 6 h(P<0.01). The production of γH2AX was 25.67,18.36,12.43 and 14.25 for the four types of genotoxic agents,respectively,and was approximately 19,13,9 and 11 times that of the vehicle control group(P<0.01)at the optimum time point and concentration. There was a significant positive corre?lation between the indicated concentrations of genotoxic chemicals and γH2AX expression levels(P<0.01). In addition,the production ofγH2AX indicated no marked increase in two non-genotoxic agents such as Aza and CsA in comparison with the control group. CONCLUSION This test method can effec?tively distinguish genotoxic agents from non-genotoxic agents,and direct genotoxic agents from indirect genotoxic agents in the absence of S9. γH2AX might be a reliable marker for the identification of the potential genotoxicity of chemicals.
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Objective To study the clinical efficacy of acupuncture combined with medication plus joint mobilization in the treatment of lumbar intervertebral disc protrusion accompanied with secondary lumbar spinal stenosis.MethodsTotally 66 cases of lumbar intervertebral disc protrusion accompanied with secondary lumbar spinal stenosis were collected randomly and divided into treatment group (34 cases) and control group (32 cases). The control group was given treatment of simple acupuncture and TCM medication, while the treatment group was given joint mobilization treatment besides acupuncture and TCM medication. Functions of lumbar vertebra were evaluated by ODI scale and the degrees of pain were evaluated by VAS. The clinical efficacy in the two groups was compared. Results ODI in both groups were significantly improved after treatment compared with that before treatment. However, the changing range of the ODI of the treatment group was more significant than that in control group (P<0.01). After treatment, VAS scores were relieved (P<0.05) in both groups, and treatment group was more significant than that in control group (P<0.05). The total clinical efficacy was 97.06% (33/34) in the treatment group, and 84.38% (27/32) in the control group, with statistical significance (P<0.05).Conclusion Acupuncture combined with medication plus joint mobilization in the treatment of lumbar intervertebral disc protrusion accompanied with secondary lumbar spinal stenosis has good efficacy.
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<p><b>OBJECTIVE</b>To investigate the effect of occupational exposure to toluene diisocyanate (TDI) on the workers' health.</p><p><b>METHODS</b>A total of 76 workers exposed to TDI (exposure group) and 64 management staff members (control group) were selected from a factory as the study subjects. Area sampling was performed for the place with exposure to TDI according to the method in GBZ 159-2004 Specifications of air sampling for hazardous substances monitoring in the workplace, and gas chromatography was applied to measure the concentration of TDI in workplace air. The workers' personal information was collected with questionnaire, pulmonary ventilation function was determined with a portable spirometer, hematological parameters were analyzed by automatic blood analyzer and blood chemistry analyzer, and the indicators of oxidative damage and energy metabolism were measured by the reagent kit provided by Nanjing Jiancheng Bioengineering Institute. SPSS 17 software was applied for statistical analysis.</p><p><b>RESULTS</b>The exposure group had significantly lower forced vital capacity (FVC), forced expiratory volume in 1 second(FEV1.0), and FEV1.0/FVC ratio than the control group (P <0.05). Compared with the control group, the exposure group had significantly higher red blood cell count, platelet distribution width, mean platelet volume, lymphocyte count, and neutrophil count(P<0.01), and significantly lower activities of lactate dehydrogenase(LDH), superoxide dismutase, and succinodehydrogenase (SDH)(P <0.01). In the exposure group, the length of exposure was negatively correlated with the activities of SDH and LDH in the serum (r=-0.319, P <0.05; r=-0.239, P <0.05), and the length of exposure was not found to be correlated with the activity of SOD and pulmonary function indices.</p><p><b>CONCLUSION</b>TDI can induce inflammatory response and lung ventilation function impairment in workers exposed to TDI, as well as oxidative stress and imbalance of energy metabolism. Therefore, it can cause damage to workers' health, and protective measures should be enhanced.</p>
Subject(s)
Humans , Case-Control Studies , Erythrocyte Count , Forced Expiratory Volume , Inflammation , L-Lactate Dehydrogenase , Blood , Metabolism , Leukocyte Count , Lung , Occupational Exposure , Pulmonary Ventilation , Succinate Dehydrogenase , Blood , Metabolism , Superoxide Dismutase , Metabolism , Toluene 2,4-Diisocyanate , Vital CapacityABSTRACT
<p><b>OBJECTIVE</b>To describe the distribution of zinc (Zn) and copper (Cu) in urine samples of generalpopulation in eight provinces of China, to analyze their characteristics of distribution between different region, gender and age-cohorts, and to provide the baseline of themetabolites in the general population.</p><p><b>METHODS</b>From 2009 to 2010, 18 120 subjects from the general population aged from 6 to 60 years old were recruited from 24 areas among 8 provinces of China mainland by random sampling. The environmental and physical condition characteristics were collected from questionnaires, and urine samples were collected at the mean time. The levels of Zn and Cu in urine were measured using ICP-MS. Data were analyzed by statistical methods to compare the distribution characteristics of Zn and Cu among populations with different ages and genders.</p><p><b>RESULTS</b>Totally, the median of Cu and Zn in urine were 9.28 and 115.47 µg/L respectively; and the inter-quartile range of Cu and Zn were 2.66-16.09 and 35.32-265.15 µg/L respectively. The median of Cu in male and female were 9.90 and 8.60 µg/L (Z=-5.63, P<0.001), and Zn in male and female were 140.44 and 95.27 µg/L (Z=-14.79, P<0.001). The median of Cu among the groups aged 6-12, 13-16, 17-20, 21-30, 31-45 and 46-60 years old were 9.30, 10.14, 9.67, 9.33, 8.38 and 8.74 µg/L (χ2=70.94, P<0.001), respectively, and the median of Zn 130.83, 132.07, 139.34, 109.3, 78.74 and 109.51 µg/L ((χ2=146.00, P<0.001), respectively.There was statistically significant differences in urinary Cu and Zn levels between male and female, and among the different age groups.</p><p><b>CONCLUSION</b>The Cu and Zn levels and distribution in urine among general population between 2009 and 2010 in China were reported in this article. These basic data in China will provide scientific and reliable reference for further scientific research.</p>
Subject(s)
Adolescent , Adult , Child , Female , Humans , Male , Middle Aged , Age Factors , China , Copper , Urine , Environment , Sex Factors , Surveys and Questionnaires , Zinc , UrineABSTRACT
<p><b>OBJECTIVE</b>To systematically evaluate the environmental exposure information of coke oven workers, we investigated the concentration and size distribution characteristics of the particle matter (PM) in the top working area of coke oven.</p><p><b>METHODS</b>The aerodynamic particle sizer spectrometer was employed to collect the concentration and size distribution information of PM at a top working area. The PM was divided into PM ≤ 1.0 µm, 1.0 µm < PM ≤ 2.5 µm, 2.5 µm < PM ≤ 5.0 µm, 5.0 µm < PM ≤ 10.0 µm and PM>10.0 µm based on their aerodynamic diameters. The number concentration, surface area concentration, and mass concentration were analyzed between different groups. We also conducted the correlation analysis on these parameters among groups.</p><p><b>RESULTS</b>We found the number and surface area concentration of top area particulate was negatively correlated with particle size, but mass concentration curve showed bimodal type with higher point at PM = 1.0 µm and PM = 5.0 µm. The average number concentration of total particulate matter in the top working area was 661.27 number/cm³, surface area concentration was 523.92 µm²/cm³, and mass concentration was 0.12 mg/m³. The most number of particulate matter is not more than 1 µm (PM(1.0)), and its number concentration and surface area concentration accounted for 96.85% and 67.01% of the total particles respectively. In the correlation analysis, different particle size correlated with the total particulate matter differently. And the characteristic parameters of PM2.5 cannot fully reflect the total information of particles.</p><p><b>CONCLUSION</b>The main particulate matter pollutants in the top working area of coke oven is PM1.0, and it with PM(5.0) can account for a large proportion in the mass concentration of PM. It suggest that PM1.0 and PM(5.0) should be considered for occupational health surveillance on the particulate matter in the top area of coke oven.</p>
Subject(s)
Humans , Air Pollutants, Occupational , Coke , Occupational Exposure , Particle Size , Particulate Matter , WorkplaceABSTRACT
<p><b>OBJECTIVE</b>To investigate the cell proliferation and genome stability in workers with occupational exposure to diesel exhaust (DE).</p><p><b>METHODS</b>In 2012, 117 DE-exposed workers and 106 control workers were recruited by cluster sampling in this study. The demographic data were obtained by questionnaire survey. The airborne fine particle and enriched polycyclic aromatic hydrocarbons (PAHs) at different workplaces were collected and analyzed. The concentrations of main PAHs monohydroxy metabolites in the urine were determined by high performance liquid chromatography-mass spectrometry (LC-MS), which could reflect the internal exposure level of DE. The cell proliferation capacity and genome stability in the periphery lymphocytes of workers were evaluated by cytokinesis-block micronucleus (CBMN) cytome assay.</p><p><b>RESULTS</b>The concentrations (median (P5-P95)) of total PAHs monohydroxy metabolites in the urine of exposed group and control group were 12.96 (4.73-28.10), 4.76 (0.90-15.00) µg/L, respectively, and the exposed group was higher than that of controls (Z = -8.77, P < 0.001). The nuclear division index (NDI) of exposed group and control group was 1.68±0.13, 1.85±0.16, respectively, and the NDI of exposed group showed significantly decreased (t = 8.86, P < 0.001), while the genome instability index calculated by micronucleus, nuclear bridges and nuclear buds, of exposed group and control group was 13.27±6.26, 4.83±3.38, respectively, and the exposed group had statistically significant increase (Z = -10.08, P < 0.001). The tertiles of total PAHs monohydroxy metabolites in the urine were categorized into low, medium and high groups (<5.96, 5.96-12.46, >12.46 µg/L). With the NDI decreased, 1.81±0.17, 1.79±0.17, 1.68±0.14 (F = 13.14, P < 0.001), genome instability index began to increase 5.80±4.15, 9.97±7.14, 11.99±6.61 (/1 000), respectively (χ(2) = 36.74, P < 0.001). With the increase of total PAHs monohydroxy metabolites level in corresponding groups. In addition, the NDI was negatively correlated with the frequencies of micronucleus, nuclear bridges, nuclear buds and genome instability index, respectively, and the difference was statistically significant (P < 0.001).</p><p><b>CONCLUSIONS</b>DE exposure lead to inhibition of cell proliferation capacity and increase genome instability in the peripheral lymphocytes of occupational-exposed population, providing important clues and evidence for early biomarkers monitoring.</p>
Subject(s)
Humans , Biomarkers , Cell Proliferation , Chromatography, Liquid , Genomic Instability , Lymphocytes , Micronucleus Tests , Occupational Exposure , Particulate Matter , Polycyclic Aromatic Hydrocarbons , Surveys and Questionnaires , Vehicle Emissions , WorkplaceABSTRACT
<p><b>OBJECTIVE</b>To estimate the reference value for micronucleus frequency of peripheral blood lymphocytes in general Chinese population, and to guide the genotoxicity evaluation and risk analysis for populations exposed to environmental or occupational chemicals.</p><p><b>METHODS</b>A fulltext search was performed in CNKI with the key words of "micronucleus" and "human", and PubMed was searched with "cytokinesis-block micronucleus","CBMN","humans", and "adults", to obtain the articles published at home and abroad from 2001 to 2014 in which cytokinesis-block micronucleus (CBMN)assay was applied for micronucleus detection and populations not exposed to genotoxins were established as a control. Monte Carlo simulation was performed based on the micronucleus frequency, standard deviation, and sample size provided in these articles to calculate the micronucleus frequency for general population and to analyze the influence of sex, smoking, and drinking on micronucleus frequency.</p><p><b>RESULTS</b>A total of 23 articles were included in the final analysis. The minimum mean micronucleus frequency was 0.39‰, and the maximum mean micronucleus frequency was 25.3‰. There were 1623 subjects in the control group in total (range 22~178, mean 70.6). Monte Carlo simulation was performed 100 times, and the mode of micronucleus frequency was 0 or 1‰; the values of P0, P25, P50 , P75, and P95 were 0‰, 1‰, 2‰~3‰, 5‰~6‰, and 14‰~19‰, respectively; the mean value was 4.36‰(range 4.22‰~4.57‰). With the application of one-sided 95% range(x±1.64 s), the upper limit of the range of reference value was calculated to be 13.46‰~14.75‰.</p><p><b>CONCLUSION</b>The micronucleus frequency of peripheral blood lymphocytes in general Chinese population is 4.36‰, the interquartile range is 1‰~5‰ or 1‰~6‰, and the upper limit of reference value is 14.17‰. The factors of living area, sex, smoking, and drinking may influence micronucleus frequency.</p>