Occupational Exposure Population Research Articles

Prediction and validation of mild cognitive impairment in occupational dust exposure population based on machine learning

ObjectiveWorkers exposed to dust for extended periods may experience varying degrees of cognitive impairment. However, limited research exists on the associated risk factors. This study aims to identify key variables using machine learning algorithms (ML) and develop a model to predict the occurrence of mild cognitive impairment in miners. Methods: A total of 1938 miners were included in the study. Univariate analysis and multivariable logistic regression were employed to identify independent risk factors for cognitive impairment among miners. The dataset was randomly divided into a training set and a validation set in an 8:2 ratio of 1550 and 388 individuals, respectively. An additional group of 351 miners was collected as a test set for cognitive impairment assessment. Seven machine learning algorithms, including XGBoost, Logistic Regression, Random Forest, Complement Naive Bayes, Multi-layer Perceptron, Support Vector Machine, and K-Nearest Neighbors, were used to establish a predictive model for mild cognitive impairment in the dust-exposed population, based on baseline characteristics of the workers. The predictive performance of the models was evaluated using the Area Under the Receiver Operating Characteristic Curve (AUC), and the XGBoost model was further explained using the Shapley Additive exPlanations (SHAP) package. Cognitive function assessments using rank sum tests were conducted to compare differences in cognitive domains between the mild cognitive impairment group and the normal group. Results: Univariate and multivariable logistic regression analyses revealed that education level, Age, Work years, SSRS (Self-Rating Scale for Stress), and HAMA (Hamilton Anxiety Rating Scale) were independent risk factors for cognitive impairment among dust-exposed workers. Comparative analysis of the performance of the seven machine learning algorithms demonstrated that XGBoost (training set: AUC=0.959, validation set: AUC=0.795) and Logistic Regression (training set: AUC=0.818, validation set: AUC=0.816) models exhibited superior predictive performance. Results from the test set showed that the AUC of the XGBoost model (AUC=0.913) outperformed the Logistic Regression model (AUC=0.778). Miners with mild cognitive impairment exhibited significant impairments (p<0.05) in visual-spatial abilities, attention, abstract thinking, and memory areas. Conclusion: Machine learning algorithms can predict the risk of cognitive impairment in this population, with the XGBoost algorithm showing the best performance. The developed model can guide the implementation of appropriate preventive measures for dust-exposed workers.

Analysis of clinical characteristics of 129 acute and chronic occupational brucellosis in HulunBuir City

Objective: To analyze the epidemiological characteristics and clinical data of acute and chronic occupational brucellosis patients in order to provide a scientific basis for the prevention and treatment of occupational brucellosis. Methods: In October 2022, a study was conducted on 129 patients diagnosed with occupational brucellosis by HulunBuir Center for Disease Control and Prevention from January 2016 to December 2021. The epidemiological characteristics, clinical features, and laboratory test results of patients in the acute and chronic phases were compared and analyzed using chi-square test and student's t test. Results: The acute phase patients included 38 men and 4 women with an average age of (36.6±8.4) years old; the chronic phase patients included 73 men and 14 women with an average age of (38.4±7.9) years old. There were no significant differences in gender and age between the two groups (P>0.05). The patients had a clear history of occupational exposure, and the proportion of veterinarians in acute stage (21 cases, 50.0%) was significantly higher than that in chronic stage (25 cases, 28.7%), the difference was statistically significant (P<0.05). The symptoms of fever and loss of appetite in acute phase of occupational brucellosis were significantly higher than those in chronic phase, and the symptoms of fatigue and joint muscle pain were significantly lower than those in chronic phase, with statistical significances (P<0.05). The increase of alanine aminotransferase, aspartate aminotransferase, C-reactive protein, erythrocyte sedimentation rate and positive rate of blood culture in acute stage were significantly higher than those in chronic stage, with statistical significances (P<0.05) . Conclusion: Occupational brucellosis patients are predominantly middle-aged men, the acute phase is characterized by fever, loss of appetite, and increased inflammatory indicators and liver enzymes, while the chronic phase is characterized by symptoms such as fatigue and joint muscle pain. Brucellosis related occupational exposure population should seek medical treatment as soon as possible when the above symptoms occur, timely detection and treatment of occupational diseases.

Determination of six arsenic species in urine by high-performance liquid chromatography-inductively coupled plasma-mass spectrometr

Objective: Establishing an analysis method for the detection of six arsenic compounds trivalent arsenic, pentavalent arsenic, methyl arsenic, dimethyl arsenic, arsenical choline and arsenical betaine in urine by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) and providing a theoretical basis for health assessment of arsenic poisoning patients. Methods: HPLC-ICP-MS was used to detect six arsenic compounds with the hamilton PRP-X100 column and aqueous ammonium phosphate in a gradient elution as mobile phase. Results: There was a good linear relationship in the selected range of six arsenic compounds evidenced by a linear correlation coefficient greater than 0.999. The detection limit of 6 arsenic compounds was 0.46~0.57 μg/L, and the minimum quantitative concentration were 1.52~1.91 μg/L. The recovery rates of six arsenic compounds were 96.5%~106.4%, The within-run and between-run relative standard deviation was 2.9%~6.2% and 3.8%~8.7%. Conclusion: The established method with high accuracy and precision is suitable for detecting arsenic levels in urine of occupational arsenic exposure population.

Progress in research of avian influenza virus and human monoclonal antibody and vaccines against H7N9 virus

Avian influenza virus (AIV) is a kind of zoonotic virus which can cause acute respiratory infectious diseases. Since the report of the world's first human infection case of avian influenza A (H7N9) virus in China in 2013, close attention has been paid to the virus. AIV spreads widely around the world, and human infection with different types of AIV continues to occur, causing huge economic losses. At present, there are no specific treatment and drugs against the disease, and vaccination is considered as the most promising and effective method to control the human infection with AIV. So far, there are many kinds of veterinary and human vaccines for H7N9 AIV, among which four types of human H7N9 AIV vaccines have entered the clinical trial stage, including virus-like particles vaccine, attenuated live vaccine, inactivated vaccine and DNA vaccine, which have shown good safety and immunogenicity. However, the true efficacies of the AIV vaccines remain unknown because no human vaccines are currently available in the market. In addition, although the existing influenza vaccine has good safety and immunogenicity in the human population, there is no cross-antibody response to H7N9 AIV. This paper summarizes the research progress of AIV etiology and epidemiology, the occupational exposure population investigation, the infection prevention and control strategies, and H7N9 AIV vaccine and H7N9 AIV anthropogenic monoclonal antibody, and discuss the remained problems, challenges and future trends in the research of AVI to improve the understanding of the disease and the prevention and control of global spread of AIV.

Associations between exposure to polycyclic aromatic hydrocarbons and metabolic syndrome in U.S. adolescents: Cross-sectional results from the National Health and Nutrition Examination Survey (2003–2016) data

BackgroundThe metabolic syndrome is a constellation of risk factors, including abdominal obesity, hypertension, dyslipidemia, and hyperglycemia. Polycyclic aromatic hydrocarbons (PAHs) constitute a group of chemicals that are formed during the incomplete combustion of coal, oil and gas, garbage, and other organic substances. In the occupational exposure population, PAHs exposure increased the prevalence ratio of metabolic syndrome. However, the effect of PAHs on prevalence of metabolic syndrome in adolescents has not been reported. Because of the propensity for childhood metabolic risk to track into adulthood, there is a great need to identify risk factors for childhood metabolic syndrome. MethodUsing data from the 2003–2016 National Health and Nutrition Examination Survey. We defined metabolic syndrome using a modified version of the National Cholesterol Education Program Adult Treatment Panel Ⅲ definition for adolescents. Weighted logistic regression was used to calculate the odds ratio and 95 % confidence intervals for each biomarker. In addition, we applied the weighted quantile sum (WQS) regressions to adolescent metabolic syndrome to reveal the multiple exposure effects and relative weights of each PAH. ResultsAmong the 827 adolescents, 183 (22.13 %) had metabolic syndrome. The levels of 2-hydroxynaphthalene (2-NAP), 2-hydroxyphenanthrene (2-PHE), 2-hydroxyfluorene (2-FLU), 1-hydroxynaphthalene (1-NAP), 3-hydroxyfluorene (3-FLU) and 1-hydroxypyrene (1-PYR) were higher in the group of adolescents with metabolic syndrome. There were positive associations between higher concentrations of 2-NAP, 2-FLU and odds of metabolic syndrome after adjustment, which odds ratios (ORs) in the 3rd tertile were 2.22 (95%CI:1.45–3.44) and 2.09 (95%CI:1.36–3.10), respectively. In subgroups analysis, the ORs between the 3 tertile concentrations of 2-NAP, 2-PHE and high fasting blood glucose (FBG) were 2.20 (95%CI:1.37–3.57) and 1.99 (95%CI:1.16–3.48). ConclusionThe present study suggested that PAHs may be associated with odds of metabolic syndrome as well as individual metabolic syndrome components among adolescents. A cohort study should be designed to clarify the cause and effect between PAHs and metabolic syndrome in future research.

A non-targeted metabolomics study on urine of occupational exposure people with titanium dioxide nanoparticles

Objective: To investigate the effects of titanium dioxide nanoparticles (TiO(2) NPs) on urine metabolites in occupationally exposure people based on metabolomics technology, and to explore the mechanism of early health effects of TiO(2) NPs on occupational exposure. Methods: In October 2019, the TiO(2) NPs occupational exposure population was selected as the research object, of which 64 people were in the exposure group who had been engaged in TiO(2) NPs exposure positions for more than 1 year; the control group was 62 people, who were logistics administrative staff of the same company. The urine of the research subjects before class was collected, using the ultra-high performance liquid chromatography time-of-flight mass spectrometer to collect the metabolism data of the urine, Progenesis QI software for data preprocessing and metabolite identification, SIMCA-P software for the principal component analysis of the data and potential biomarkers screening, MetaboAnalyst 4.0 software for metabolic pathway enrichment analysis. Results: The urine metabolism profile of workers in the exposure group was different from the control group, and 44 potential biomarkers were screened and identified. These potential biomarkers were significantly enriched in three pathways (P<0.05) , namely D-arginine and D-ornithine metabolism pathway, nitrogen metabolism pathway and D-glutamine and D-glutamate metabolism pathways. Conclusion: The occupational exposure of TiO(2) NPs can affect the concentration of metabolites in people urine and metabolic pathways, which provides a direction for the study of occupational hazard mechanisms of TiO(2) NPs and the monitoring of health risks.

Cross-sectional study based on occupational aluminium exposure population

To evaluate the different characteristics of cognitive impairment caused by occupational aluminium exposure at different ages, we surveyed 1660 workers in Shanxi Aluminium Plant, China, and assessed their cognitive function and plasma aluminium concentration. In multiple linear regression, the scores of the digit-span test (DST) and digit-span backward test (DSBT) were negatively correlated with plasma aluminium concentration when concentration reached 34.52 μg/L in younger group (＜40 years), while in the middle-aged group (≥40 years) only found when concentration reached 42.25 μg/L (β<0, P < 0.05). In logistic regression, when plasma aluminum concentration reached 42.25μg/L, odds ratios (95 % confidence interval) were 1.695 (1.062–2.705) and 3.270 (1.615–6.620) for DST, 7.644 (3.846–15.192) and 15.308 (4.180–56.059) for DSBT in middle-aged group and younger group, respectively. These results showed that aluminium exposures were associated with cognitive impairment among aluminium-exposed workers, particularly for young workers who were more susceptible.

Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection

Pigs are considered as important hosts or "mixing vessels" for the generation of pandemic influenza viruses. Systematic surveillance of influenza viruses in pigs is essential for early warning and preparedness for the next potential pandemic. Here, we report on an influenza virus surveillance of pigs from 2011 to 2018 in China, and identify a recently emerged genotype 4 (G4) reassortant Eurasian avian-like (EA) H1N1 virus, which bears 2009 pandemic (pdm/09) and triple-reassortant (TR)-derived internal genes and has been predominant in swine populations since 2016. Similar to pdm/09 virus, G4 viruses bind to human-type receptors, produce much higher progeny virus in human airway epithelial cells, and show efficient infectivity and aerosol transmission in ferrets. Moreover, low antigenic cross-reactivity of human influenza vaccine strains with G4 reassortant EA H1N1 virus indicates that preexisting population immunity does not provide protection against G4 viruses. Further serological surveillance among occupational exposure population showed that 10.4% (35/338) of swine workers were positive for G4 EA H1N1 virus, especially for participants 18 y to 35 y old, who had 20.5% (9/44) seropositive rates, indicating that the predominant G4 EA H1N1 virus has acquired increased human infectivity. Such infectivity greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses.

Association between PON2 gene polymorphisms and susceptibility to noise-induced hearing loss

Objective: To investigate the relationship between SNP and noise-induced hearing loss (NIHL) susceptibility in occupational noise exposure population in China. Methods: From 6297 for a certain steel works in contact with noise, contact length of 3 years or more and workplace noise exposure intensity of 80 dB (A) , ears or high frequency (3 000, 4 000, 6 000 Hz) average of hearing acuity 40 dB (HL) , or high frequency loss in both ears, on the basis of single whisper frequency (500, 1, 000, 2 000 Hz) average threshold of 26 dB (HL) or object as case group. A case-control study was designed with 1:1 matching. Subjects with the same gender, the same type of work, age ±5 years old, and working age ±2 years after noise exposure were selected as the control group. Subjects with any whisper frequency (500, 1, 000, 2, 000 Hz) whose hearing threshold in any frequency band was ≤25 dB (A) and whose average high-frequency hearing threshold in pure tone hearing test was <35 dB (A) were selected as the control group. Four sites of PON2 gene were genotyped by medium-and high-throughput SNP genotyping. Univariate logistic regression was used to analyze the relationship between single SNP polymorphism and NIHL. Results: A total of 286 case-control pairs were included. Smoking was statistically significant difference between cases and controls (P<0.001) . Conclusion: No statistical difference has been found between single SNP polymorphism and NIHL. At the level of greater than 92 dB of high noise exposure, rs7785846 (CT+TT) genotype is a risk factor for occupational noise deafness, and its OR is 2.74 (95%CI: 1.09-6.89) compared with wild homozygous type (CC) . Conclusion. The rs7785846 (CT+TT) genotype carriers of PON2 gene are more susceptible to hearing impairment when exposed to high noise intensity.

Study on the effect of occupational exposure to glyphosate on blood routine

Objective: To investigate the effect of glyphosate on blood routine of occupational exposure population. Methods: The workers who were occupationally exposed to glyphosate were selected as exposure group, and administrative staffs who were not exposed to glyphosate were selected as control group. Occupational health examination was conducted on all the subjects, and personal monitoring was applied to detect the concentration of glyphosate in the air of workplace. Time weighted average (TWA) concentration was calculated by the result of determination. Statistical methods were employed to compare the difference of blood routine results between the contact group and the control group, as well as between different posts. Results: 178 glyphosate workers were included in the contact group, and 203 non-contact persons were included in the control group. There was no statistically significant difference in the equilibrium test between the two groups(P>0.05). The abnormal rate of blood routine in the exposure group and the control group were 70.8% and 69.0%, respectively, but the difference was not statistically significant (P>0.05). Compared with the control group, the red blood cell count and platelet distribution width difference (P<0.05) were significant difference. There was no significant difference between different positions (P>0.05). Conclusion: When TWA value is below 9.40 mg/m(3), glyphosate has effect on the results of platelet distribution width and red blood cell count, but has no effect on the abnormal rate of blood routine.

Application of the in vivo Pig-a gene mutation assay to test the potential genotoxicity of p-phenylenediamine

Currently, it remains controversial whether p-phenylenediamine (PPD) is genotoxic. In this study, we evaluated the potential genotoxicity of PPD using the newly-developed Pig-a gene mutation assay. The results of three classical genetic toxicity tests (bacterial reverse mutation assay, mammalian cell chromosomal aberration test, and mammalian erythrocyte micronucleus test) are all positive, suggesting that PPD is potentially genotoxic. In Pig-a assay, Sprague-Dawley rats are orally administered with PPD for 28 consecutive days at three doses (12.5, 25, and 50 mg/kg/day). Our result shows that PPD (25 and 50 mg/kg/day) dose-dependently increases RETCD59− value over controls on Day 8. RETCD59− keeps increasing to the maximum on Day 15 and then decreases until Day 29. PPD also dose-dependently increase RBCCD59− value on Day 15, which keeps elevating until Day 29. The time-course of RETCD59− and RBCCD59− induced by PPD are similar with that induced by N-ethyl-N-nitrosourea (ENU) treatment for 3 days. Our data suggests that PPD has potential genotoxic effects, and the Pig-a assay is sensitive to assess mutagenicity. However, further investigation of the changes of RETCD59− and RBCCD59− induced by hair dyes containing PPD should be detected by Pig-a assay in occupational exposure population to confirm the safety of PPD usage.

Occupational health investigate of 1-bromopropane used in a factory

Objective: To investigate the occupational health survey of 1-brominepropane (1-BP) enterprises and understand the impact of 1-BP on the health of occupational exposure population. Methods: The occupational health data of 15 1-BP workers were collected from 3 time nodes in 0 months, June and December, and the effects of occupational exposure to 1-BP on health were analyzed. Results: In the workplace with pure 1-BP, the mean air concentration in the workplace was 26.8 mg/m(3), and the personal contact level was 29.7 to 63.4 mg/m(3). The occupational health monitoring data showed that white blood cell count (WBC) , red blood cell count (RBC) , aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were compared in 0 months, June, and 12 months, the difference was statistically significant (P<0.05) . Conclusion: During the 12 months observation period, the occupational exposure to 1-BP caused the number of peripheral blood erythrocyte and leukocyte count and the level of alanine transaminase in the workers, but it did not exceed the normal reference range.

Study of the effect of occupational exposure to glyphosate on hepatorenal function

Objective: To explore the effect of occupational exposure to glyphosate on hepatorenal function. Methods: 526 workers who were occupationally exposed to glyphosate from 5 glyphosate-producing factories were selected as cases; and another 442 administrative staffs who were not exposed to glyphosate were selected as controls from April to November, 2014. All the subjects accepted occupational health examination. The concentration level of glyphosate in the air of workshop was detected and the time weighted average concentration (TWA) was calculated. And analyze the difference of hepatorenal fuction between case group and control group. Result: The age of the subjects in the case and control groups were separately (35.6±10.3), (34.3±9.7) years old, with the length of working for (6.5±5.7), (7.7±6.8) years. The TWA of glyphosate in the case group was between <0.03-48.91 mg/m(3), with the geometric mean at 3.78 mg/m(3). The overall rates of abnormal hepatic and renal function in the case group were 14.4% (76 cases) and 16.2% (85 cases), respectively; while those were 5.0% (22 cases) and 4.8% (21 cases), respectively in control group, and the difference showed statistical significance (P<0.05). When TWA reached <0.03-6.00 mg/m(3), the difference of hepatorenal fuction between case group and control group showed statistical significance, and the rates of abnormal hepatic and renal function was 8.0% (36/447) and 9.8% (44/447) respectively in case group. When cumulative exposure level reached <1.56-68.64 g, the difference of hepatorenal fuction between case group and control group showed statistical significance, and the rates increased to 9.2% (37/404) and 10.4% (42/404) respectively in group of cases. Conclusion: Glyphosate can affect the hepatic and renal function among occupational exposure population, and there was an association between the effect and the exposure dose.

An evaluation of the protective role of vitamin C in reactive oxygen species-induced hepatotoxicity due to hexavalent chromium in vitro and in vivo

BackgroudDrinking water contamination with hexavalent chromium [Cr (VI)] has become one of the most serious public health problems, thus the investigation of Cr (VI)-induced hepatotoxicity has attracted much attention in recent years.MethodsIn the present study, by determining the indices of hepatotoxicity induced by Cr (VI), the source of accumulated reactive oxygen species (ROS), and the protective effect of the antioxidant Vitamin C (Vit C), we explored the mechanisms involved in Cr (VI)-induced hepatotoxicity in vitro and in vivo.ResultsWe found Cr (VI) caused hepatotoxicity characterized by the alterations of several enzymatic and cytokine markers including aspartate aminotransferase (AST), alanine aminotransferase (ALT), interleukine-1β (IL-1β), and tumor necrosis factor-α (TNF-α), etc. ROS production after Cr (VI) exposure was origins from the inhibition of electron transfer chain (ETC) and antioxidant system. Vit C inhibited ROS accumulation thus protected against Cr (VI)-induced hepatotoxicity in L-02 hepatocytes and in the rat model.ConclusionsWe concluded that ROS played a role in Cr (VI)-induced hepatotoxicity and Vit C exhibited protective effect. Our current data provides important clues for studying the mechanisms involved in Cr (VI)-induced liver injury, and may be of great help to develop therapeutic strategies for prevention and treatment of liver diseases involving ROS accumulation for occupational exposure population.

MA03.06 Cost Effectiveness of Chest Scan Screeing for Lung Cancer in Abestos Occupational Exposure Subjects: A Model Based Study

The National Lung Screening trial (NLST) showed that screening with low-dose computed tomography (CT) compared with chest radiography reduced lung-cancer mortality. There is very few data's on subjects with occupational asbestos exposure. We examined the cost-effectiveness of CT lung cancer screening in a French cohort of asbestos post professional exposure subjects (APEXS cohort). We estimated mean lif-years, costs and incremental cost-effectiveness ration (ICER) for screening with low-dose CT compare to no screening in this population of asbestos exposed subjects. Estimations of life-years gained were based on the efficacy of NLST trial applied to APEXS cohort, adjusted to sex and age. Costs were limited to direct costs, from the payer perspective. We also performed sensitivity analysis based on several assumptions of screening program efficacy. Compared with no screening, screening with low-dose CT, over a period of 2 years, will cost, for 1000 subjects of APEXS cohort 312 645 €, will provide 9.4 additional life-years. The corresponding ICER was 33 102 € per life-gained. Sensitivity analysis showed that this result is sensitive to screening program efficacy (number, stage, and survival diagnosed by the program). ICER of low-dose CT lung cancer program in a cohort of asbestos post occupational exposure population appears as acceptable from the French health system.

An investigation of psychological state at different stages of occupational AIDS exposure and related influencing factors in Nanning, China

Objective: To investigate the changes in psychological state after occupational exposure in the AIDS occupational exposure population and related influencing factors, and to provide baseline data and a basis for related departments to conduct mental health prevention and intervention for personnel with occupational AIDS exposure. Methods: AIDS risk assessment was performed for all personnel with occupational AIDS exposure in 2014 in Nanning, China, and the Symptom Checklist-90 (SCL-90) psychological scale was used for psychological state evaluation at 24 hours, 1 week, and 3 months after occupational exposure in all persons who met the research criteria. Results: Most of the persons with occupational AIDS exposure came from secondary and tertiary hospitals (85%) , and nurses accounted for the highest percentage (78.3% ). The age ranged from 21 to 50 years, and the mean age was 31.02 ± 7.92 years. The persons with occupational AIDS exposure aged 20~29 years accounted for the highest percentage (51.6%) , and most persons (76.7%) graduated from junior colleges. Compared with the adult norm, there was significant increases in the total psychological score and the number of positive items after occupational exposure (P<0.05). The scores of all items at 24 hours were significantly higher than those at the other time points, and the scores of all items gradually decreased over time (F=227.24, 267.57, and 287.46, P<0.05). Compared with the adult norm, there were significant increases in the factor points at 24 hours and significant reductions in the factor points at 3 months (P<0.05). Compared with those at 24 hours, the factor scores at 3 months decreased significantly (P<0.05). Conclusion: Occupational AIDS exposure affects the mental status of related personnel, and the mental status at 24 hours after exposure is poor. Related departments should provide corresponding psychological counseling for the occupational exposure population at different exposure times.

Association between GSTM1 polymorphism and DNA adduct concentration in the occupational workers exposed to PAHs: A meta-analysis

Increasing investigations have been conducted on the association between DNA adducts and glutathione S-transferase Mu 1 (GSTM1) null genotype in occupationally exposed population. However, the results were controversial. The objective of the present study was to perform a meta-analysis to better understand the possible association between DNA adduct levels and GSTM1 genotype in occupational exposure population. Among a total of 167 literature searched from frequently-used databases, 7 articles corresponding to the specific criteria were enrolled into the meta-analysis. There was a significant increase of DNA adduct levels in occupationally exposed workers compared with control groups (p=0.003). Additionally, DNA adduct levels among the carriers of null GSTM1 were significantly higher than those of active GSTM1 carriers in exposure workers (p=0.017). Egger's test (p=0.056) and Begg's test (p=0.368) indicated that there was no evidence of publication bias. In conclusion, workers exposed to polycyclic aromatic hydrocarbons (PAHs) were at high risk to form DNA adducts, and the occupationally exposed workers who carried null GSTM1 were more susceptible to damage from PAHs.

Association between Genetic Polymorphisms of 5,10-Methylenetetrahydrofolate Reductase and Cytokinesis-Block Micronucleus in Peripheral Blood Lymphocyte among 1,3-Butadiene Workers

Exploring the associations between genetic polymorphisms and susceptibility of chromosomal damage induced by 1,3-butadiene(BD) is of much importance for understanding BD carcinogenesis. In current study, we investigated the effects of MTHFR polymorphisms and MTHFR gene haplotype pairs on chromosome damage detected by the cytokinesis-block micronucleus (CBMN) assay in peripheral blood lymphocytes. The data showed that the frequencies of CBMN among BD-exposed workers were significantly associated with the MTHFR A1298C polymorphism (P=0.04 and P=0.03, respectively) by multivariate analysis of covariance. The foundings also showed that the haplotype pairs in the MTHFR gene were more likely than single SNPs to correlate with the BD-induced chromosome damage among occupational exposed workers. Gene-environment interactions between occupational BD exposure and polymorphisms of MTHFR were also evident. These results indicate that the MTHFR polymorphisms may play a role in sensitivity or genetic susceptibility in genotoxic effects of BD exposure in the occupational exposure population.

Clinical characteristics of the patients with occupational chronic carbon disulfide poisoning in a chemical fiber factory of Nanjing

To analyze the clinical characteristics of 267 cases with occupational chronic carbon disulfide (CS(2)) poisoning and to provide the basis for revising the items of periodical medical examination of workers occupationally exposed to CS(2). The subjects of present study were 267 patients with mild CS(2) poisoning diagnosed according to "Diagnostic Criteria of Occupational Chronic Carbon Disulfide Poisoning (GBZ4-2002)" from April in 2006 to May in 2010. All patients were from the same chemical fiber factory. When a subject was diagnosed as patient with CS(2) poisoning, who should interview with questionnaire which included the illness and occupational history, symptoms, individual habits. The physical examination, nervous test, cardiovascular test, biochemical test and electromyogram were performed. The rate of decreased motor conduction velocity was 87.3% (233/267 roots). The highest detection rate of slowing conduction velocity was the common peroneal motor nerve which was 48.6% (138/248 roots) and the second was median motor nerve with delay rate of 37% (155/419 roots). The main symptoms of the patients were neurasthenia, numbness and paresthesia. The rates of abnormal achilles tendon reflex and knee jerk reflex in patients were were 79.4% and 49.8%, respectively. The detected rates of patients with ST-segment changes and hypertension were 19.1% and 27.5%, respectively. The rates of hypertension, systolic pressure and diastolic pressure were 27.3%, 22.5% and 21.1%, respectively. The rates of lactate dehydrogenase (LDH), triglycerides (TG) and low density lipoprotein (LDL) were high. The detected rates of urine acid, indirect bilirubin and total bilirubin in male patients were higher than those in female patients. In addition, the abnormal detected rate of urea nitrogen and indirect bilirubin increased with exposure years. Occupational chronic CS(2) poisoning mainly affects the nervous system, as well as liver and kidney function. Detecting the median and common peroneal motor nerve conduction velocities could be the screening indicators for the peripheral nerve injury induced by CS(2) in the occupational exposure population during the periodical occupational medical examinations.

Determination of lead in blood using electrothermal atomisation atomic absorption spectrometry with a L'vov platform and matrix modifier.

Accuracy in the determination of blood lead is of primary importance in such diverse activities as screening for childhood lead poisoning, occupational exposure monitoring and population surveys. To meet the stringent requirements of the third National Health and Nutrition Examination Survey (NHANES III), a large normative population study to be held from 1988–1994, we needed a method for the determination of lead in blood that was simple, accurate, rugged and of defined accuracy for both calibration and control materials. The recent availability of the National Bureau of Standards Standard Reference Materials 2121–2 and 955, a lead standard solution (10 000 mg l–1) and a certified lead in blood reference material has made it possible to evaluate a method against definitive values and NBS reference materials.In the proposed method, sample preparation consists of a simple dilution (1 + 9) with a matrix modifier which contains 0.5%V/V Triton X-100, 0.2%V/V 16 M nitric acid and 0.2%m/V dibasic ammonium phosphate. This matrix modifier stabilises lead so that the majority of the blood matrix may be removed during the char step. Maximum accuracy in dilution is achieved with the use of autopipettes which have been shown to deliver viscous materials such as blood and serum with high accuracy. The method described in this study has a detection limit of about 0.07 µmol l–1(3 SD) and a precision and accuracy of ±2–5% at the 0.24–2.4 µmol l–1 concentration level. Linearity has been demonstrated up to about 4 µmol l–1. Comparability has been established with the previous blood lead analytical method used in other surveys via the analysis of 435 specimens by both the previous (modified Delves cup) and proposed methods. The equation of the resulting line is [ETA-AAS]= 1.0007[Delves]– 0.051, r= 0.924.