Effects of Micronucleus Frequencies and Mitochondrial DNA Copy Numbers among Benzene-Exposed Workers in China.

To provide a more comprehensive understanding of genotoxic effects from benzene exposure, its effects on induction of mitochondrial DNA copy number (MtDNAcn) and of micronucleus (MN) were investigated using peripheral blood from workers in China. Changes in mtDNAcn and MN were determined using quantitative real-time polymerase chain reaction (PCR) and cytokinesis-block micronucleus assays (CBMN), respectively, in 58 control and 174 benzene-exposed workers in Shanghai, China. Among the exposed workers, relative mtDNAcn increased and then decreased with increasing doses of benzene exposure. Significant and dose-dependent increase in MN frequencies were observed among the different exposure groups. In addition, the relative mtDNAcn were significantly associated with the MN frequencies in the low-level exposure group (P = 0.046), but not in the high dose groups. Therefore, the mechanisms for induction of MtDNAcn and MN by benzene may be similar from exposure to low doses but different from high doses. Similar increase of MN frequencies and MtDNAcn may be due to oxidative stress induced by benzene at low concentrations, while higher concentrations may start to initiate the cell death pathway. The pathway may be associated with excessive MtDNAcn which can initiate apoptosis while MN can continue to be induced. However, the differential mechanisms need to be investigated because they may represent different levels of risk for different health consequences. On the other hand, our data indicate that induction of MtDNAcn may be a sensitive genotoxic biomarker for workers with exposure to low dose of benzene. Environ. Mol. Mutagen. 61:355-360, 2020. © 2020 Wiley Periodicals, Inc.

[Hierarchical regression analysis for relationship between job stress and job burnout in Shanghai employees].

OBJECTIVE: To identify related factors of job burnout in Shanghai employees. METHODS: Four hundred fifty-six employees in Shanghai were investigated in this study. Self-administered questionnaires were used to assess job burnout and job stress, based on Maslach Burnout Inventory and the Job Demand-Control model as well as Effort-Reward Imbalance Model. Hierarchical linear regression was employed to analyze the relationship of job burnout to personal characteristics and job stress. RESULTS: The indexes of three dimensions of job burnout were emotional exhaustion 19.70 +/- 8.92, depersonalization 11.95 +/- 4.45 and reduced personal accomplishment 28.10 +/- 10.08. Job stress was found to be affected differently in three dimensions of job burnout. Job demand, effort and over-commitment had positive impact on emotional exhaustion. Job control had a negative association with emotional exhaustion. There were significant relationship between depersonalization and age, sex and education of employees. Job control, reward and over-commitment affected the index of depersonalization. Education level and social support increased personal accomplishment index. CONCLUSION: It is necessary to reduce job stress and care about personal characteristics in preventing job burnout.

[Reliability and validity of Burnout Questionnaire in occupational population].

OBJECTIVE: To evaluate the reliability and validity of simple Burnout Questionnaire in occupational population. METHODS: A self-administered Burnout Questionnaire comprising 19 items was developed in light of Maslash Burnout Questionnaire and used for investigating 458 employees. RESULTS: Cronbach's alpha between total items of Burnout Questionnaire and each factor fell in between 0.82 and 0.85 through the consistency test. All 19 items of Burnout Questionnaire were subjected to factor analysis, and three latent factors were identified, wherein 56.3% of total variance could be explained. According to the contents described in the items and Maslash burnout theory, they were emotional exhaustion, depersonalization, and personal accomplishment. According to the covariance and the variance analysis, there was significant difference in the integral of the type of work among the three subitems (P < 0.01); there was significant difference in the integral of depersonalization between two sexes (P < 0.01); There were significant difference in the integral of the personal achievement among different level of education (P < 0.01). CONCLUSION: The reliability and validity of Burnout Questionnaire is acceptable and can be used for assessing burnout in occupational population.

[Study on the effects of lead from small industry of battery recycling on environment and children's health].

OBJECTIVE: In order to minimize lead pollution and to protect the identified individuals with high blood lead level from lead contamination, an epidemiological study was carried on children living around the village and township-owned lead industries in Tianying town. METHODS: Environmental monitoring: lead levels in air, soil, drinking water and crops were measured. Biological monitoring: 959 children aged 5 - 12 years were selected from villages where the lead smelters located near the residential areas and the battery disassembling was done in some families. The control children (207 pupils) were from other villages without lead exposure. Blood lead, ZnPP and teeth lead were determined. Height, weight and head circle of children and IQ scores were measured. RESULTS: The environment was seriously polluted. The average lead concentrations in air and soils were 8.5 times and 10 times of the MACs (national health standard) respectively. Eighty-five per cent the air samples with lead concentrations higher than the national health standard. Local crops and wheat at farmers' home were also contaminated by lead dust, with. Lead content being 24 times higher than the standard. The mean blood lead and ZnPP levels of children lived in the polluted areas were 496 microgram/L and 9.41 microgram/g Hb respectively. The lead exposure caused adverse effects on children's IQ and physical development. CONCLUSION: It is necessary to remove and reduce currently active sources of lead pollution in the community and to increase public awareness of potential health effects of lead exposure.