Metagenomic analysis of gut microbiome and resistome of Whooper and Black Swans: a one health perspective.

BACKGROUND: With the promotion of "One Health," the health of animals and their impact on the environment have become major concerns recently. Widely distributed in China, the whooper swans (Cygnus cygnus) and black swans (Cygnus atratus) are not only important to the ecological environment, but they may also potentially influence public health security. The metagenomic approach was adopted to uncover the impacts of the gut microbiota of swans on host and public health. RESULTS: In this study, the intestinal microbiome and resistome of migratory whooper swans and captive-bred black swans were identified. The results revealed similar gut microbes and functional compositions in whooper and black swans. Interestingly, different bacteria and probiotics were enriched by overwintering whooper swans. We also found that Acinetobacter and Escherichia were significantly enriched in early wintering period swans and that clinically important pathogens were more abundant in black swans. Whooper swans and black swans are potential reservoirs of antibiotic resistance genes (ARGs) and novel ARGs, and the abundance of novel ARGs in whooper swans was significantly higher than that in black swans. Metagenomic assembly-based host tracking revealed that most ARG-carrying contigs originated from Proteobacteria (mainly Gammaproteobacteria). CONCLUSIONS: The results revealed spatiotemporal changes in microbiome and resistome in swans, providing a reference for safeguarding public health security and preventing animal epidemics.

The Effect of PCDH15 Gene Variations on the Risk of Noise-induced Hearing Loss in a Chinese Population.

Noise-induced hearing loss (NIHL) is a complex disease caused by interactions between environmental and genetic factors. This study investigated whether genetic variability in protocadherin related 15 (PCDH15) underlies an increased susceptibility to the development of NIHL in a Chinese population. The results showed that compared with the TT genotype of rs11004085, CT/CC genotypes were associated with an increased risk of NIHL [adjusted odds ratio (OR) = 2.64; 95% confidence interval (CI): 1.14-6.11, P = 0.024]. Additionally, significant interactions between the rs11004085 and rs978842 genetic variations and noise exposure were observed in the high-level exposure groups (P < 0.05). Furthermore, the risk haplotype TAGCC was observed when combined with higher levels of noise exposure (P < 0.05). Thus, our study confirms that genetic variations in PCDH15 modify the susceptibility to NIHL development in humans.

Development of Job Burden-capital Model of Occupational Stress: An Exploratory Study.

This study proposes a new framework as job burden-capital model for comprehensive assessment on occupational stress. 1618 valid samples were recruited from electronic manufacturing service industry in Hunan province by self-rated questionnaires after written consent. Structural equation model analysis was employed to verify the model by the data collected. The final fitting model has satisfactory fitting goodness (CMIN/DF=5.78, AGFI=0.937, NNFI=0.960, IFI=0.968, RMSEA=0.054). Both of the measurement model and structural model have acceptable path loadings. Job burden and capital could either directly affect occupational outcomes or indirectly influence them through personality. Multi-group structural equation model analyses indicate general applicability of the model to the basic features of such population. The job burden-capital model opens up new horizons for more in-depth study on occupational stress.

Establishment of a reference value for chromium in the blood for biological monitoring among occupational chromium workers.

The concentration of chromium in the blood (CrB) has been confirmed as a biomarker for occupational chromium exposure, but its biological exposure indices (BEIs) are still unclear, so we collected data from the years 2006 and 2008 (Shandong Province, China) to analyze the relationship between the concentration of chromium in the air (CrA) of the workplaces and CrB to establish a reference value of CrB for biological monitoring of occupational workers. The levels of the indicators for nasal injury, kidney (ß2 microglobulin (ß2-MG)), and genetic damages (8-hydroxy-deoxyguanosine (8-OHdG) and micronucleus (MN)) were measured in all subjects of the year 2011 (Henan Province, China) to verify the protective effect in this reference value of CrB. Compared with the control groups, the concentrations of CrA and CrB in chromium exposed groups were significantly higher (P < 0.05). Positive correlations were found between CrA and CrB in chromium exposed groups (r 2006 = 0.60, r 2008 = 0.35) in the years 2006 and 2008. According to the occupational exposure limitation of CrA (50 µg/m(3), China), the reference value of CrB was recommended to 20 µg/L. The levels of nasal injury, ß2-MG, 8-OhdG, and MN were not significantly different between the low chromium exposed group (CrB ≤ 20 µg/L) and the control group, while the levels of ß2-MG, 8-OHdG, and MN were statistically different in the high chromium exposed group than that in the control group. This research proved that only in occupational workers, CrB could be used as a biomarker to show chromium exposure in the environment. The recommended reference value of CrB was 20 µg/L.

How Work Organization Affects the Prevalence of WMSDs: A Case-control Study.

OBJECTIVE: In this study, we aimed at exploring the association between work-related musculoskeletal disorders (WMSDs) and work organization based on a case-control study. METHODS: A total of 1938 workers who claimed to suffer from WMSDs were selected from Beijing, Henan, Hubei, and the Guangdong province. The control group consisted of 2009 workers employed in similar industries without severe disease or musculoskeletal discomforts. We used a modified version of the questionnaire developed by the NMQ and the DMQ to investigate individual and work-related factors. RESULTS: A total of 13 variables (P<0.1) were selected by the chi-square test and finally, 7 variables entered into the equation, with 6 variables reaching statistical significance (P<0.05). The odds ratios (OR) of 'work changing with season' and 'sufficient rest time' did not reach 1 (0.749 and 0.441, respectively). In addition, 'sufficient rest time' seemed to be the stronger protective factor according to its higher standardized coefficient. And 'repetitive work every minute', 'constantly repetitive work' (every day), 'shortage of site personnel', and 'often switching shifts with others' seemed to be the risk factors. CONCLUSION: Work organization may have comprehensive effects on the occurrence of WMSDs. This pattern of associations suggests that further investigation into the mechanism of how work organization affects the prevalence of WMSDs is required.

[Immunogenicity evaluation of Mycobacterium tuberculosis MPT83 protein and establishment of serological diagnostic method for bovine tuberculosis detection].

OBJECTIVE: The aim of this study was to express Mycobacterium tuberculosis MPT83 protein and to evaluate its immunogenicity in murine model as well as the serological diagnosis potential value for bovine tuberculosis. METHODS: The fragment of mpt83 gene was amplified and constructed into pET30a(+)-mpt83 recombinant plasmid. MPT83 fusion protein was purified with His affinity chromatography column from strain of BL21(DE3)-pET30a(+)-mpt83 after induced by IPTG, and then used to evaluate its immunogenicity in mice and the potential application in ELISA assay for the detection of bovine tuberculosis. RESULTS: SDS-PAGE and Western blot results show that MPT83 fusion protein was expressed successfully and possessed a good immunological reactivity. Flow cytometry (FCM) analysis displayed decreased expression of CD80 on dendritic cells and up-regulation of CD69 expression on both splenic CD4+ and CD8+ T cells. Meanwhile, more IL-4 specific secreting cell spots rather than those of IFN-γ were detected by ELISPOT assay in C57BL/6 mice injected with the fusion protein. Total 200 serum samples were detected by indirect ELISA based on MPT83 as antigen and the results showed 48.6% positive coincidence rate and 90% negative's compared to results of peripheral blood specific IFN-γ release assay in bovine tuberculosis detection. CONCLUSIONS: MPT83 fusion protein was expressed successfully with capability of eliciting Th2 immune response in mice and could be used for ELISA assay to detect bovine tuberculosis as a serological diagnosis antigen.

Generation and application of a 293 cell line stably expressing bovine interferon-gamma.

A stable mammalian cell line expressing highly active bovine interferon-gamma (BoIFN-γ) was generated using Flp recombinase-mediated integration. This recombinant 293 cell line (B1) efficiently secreted FLAG-tagged BoIFN-γ protein into the culture supernatant, as determined by ELISA and Western blot. The recombinant BoIFN-γ exhibited high anti-viral activity, suggesting that the 293 cells expressed BoIFN-γ that structurally and biologically resembled the natural protein. Two monoclonal antibodies (mAbs) with high affinity for the 293 cell-expressed BoIFN-γ were identified using this cell line, and these mAbs can be used for the development of diagnostic kits. Thus, this work demonstrates the successful generation of a 293 cell line that produces large quantities of highly active BoIFN-γ and demonstrates its potential application in the research of bovine infectious diseases.

[Prokaryotic expression and immunological characteristics of Mycobacterium tuberculosis Rv1886c].

OBJECTIVE: Ag85B (Rv1886c) is secreted during the early stages of infection by Mycobacterium tuberculosis. The purpose of this study was probed into the immune response against Ag85B in vivo. METHODS: Ag85B was prokaryotic expressed and identified, its immunological characteristics were evaluated with indirect-ELSIA, Sandwich-ELISA and RESULTS: Ag85B was mainly expressed in form of inclusion body enzyme-linked immunospot assay (ELISPOT). confirmed by SDS-PAGE. Western blot analysis shows that the fusion protein had good specific reaction with serum of tuberculosis patient and serum of mice immunized with LM-Ag85B. C57BL/6 mice were subcutaneously immunized with Ag85B, the production of IFN-gamma and IL-4 in the spleen cells was determined by Sandwich ELISA, the level of IFN-gamma was significantly higher than that of IL-4 (P < 0.001) in the Ag85B immunization group, it indicated the protein induced Th1-tendency immune responses. Furthermore, purified protein derivative (PPD) used as coating antigen, antibody titer against Ag85B in murine serum reached 1:6400, it was demonstrated that Ag85B could also induce humoral immune responses. Additionally, C57BL/6 mice were intravenously immunized with M. tb H37Rv and bacillus Calmette-Guérin (BCG) respectively for 42 days, M. tb H37Rv group intended to induce Ag85B specific Th1 type immune response, and its ability of eliciting cellular immunity was significantly stronger than BCG group (P < 0.001). CONCLUSION: Ag85B can affectively induce strongly Th1-tendency immune response and humoral response. Whereas, BCG prime vaccination only can elicit low levels of Ag85B(240-259) specific immune response. The study laid foundation for probing the pathogenic mechanism, the development of novel vaccine and the establishment of clinical diagnostic method.

Predominance of the Blastocystis subtype ST5 among free-living sympatric rodents within pig farms in China suggests a novel transmission route from farms.

Blastocystis is a parasitic protist that can infect humans and various domestic and wild animals. However, there is limited research on the prevalence of this parasite among rodents, particularly those living in pig farm settings. Therefore, to investigate the occurrence, molecular characterization, and zoonotic potential of Blastocystis among rodents within pig farm environments, we conducted an investigation of 227 rodents and shrews from 34 pig farms located in Henan, Shaanxi, and Shanxi provinces of China using nested PCR of the SSU rRNA gene of Blastocystis. The potential transmission and public health implications were also assessed from a One Health perspective. Blastocystis was detected in 86 (37.9%) fecal samples. The highest infection rate was observed among Ruttus norvegicus (73.7%, 42/58), followed by Ruttus tanezumi (30.1%, 41/136), and Mus musculus (12.0%, 3/25). However, it was not detected among individuals with Apodemus agrarius (n = 1) and Crocidura shantungensis (n = 7). Five known zoonotic Blastocystis subtypes (ST1-ST5) were identified, with ST4 (51.2%, 44/86) and ST5 (40.7%, 35/86) being the predominant ones, followed by ST1 (3.5%, 3/86), ST3 (3.5%, 3/86), and ST2 (1.2%, 1/86). ST4 was prevalent among R. norvegicus (83.3%, 35/42), while ST5 dominated R. tanezumi (70.7%, 29/41). Furthermore, ST5 exhibited the widest distribution at pig farm level, accounting for 65.0% (13/20) of Blastocystis-positive pig farms. This investigation presents the first documented Blastocystis infection in R. tanezumi and M. musculus, highlighting the predominant presence of the zoonotic ST5 subtype in rodents for the first time. The results demonstrate that sympatric rodents can serve as natural reservoirs for Blastocystis and play a role in its transmission. These findings provide information on the dynamics of rodent transmission and emphasize the potential public health threat posed by zoonotic Blastocystis subtypes spillover from pig farms.

Identification of a Hippocampus-to-Zona Incerta Projection involved in Motor Learning.

Motor learning (ML), which plays a fundamental role in growth and physical rehabilitation, involves different stages of learning and memory processes through different brain regions. However, the neural mechanisms that underlie ML are not sufficiently understood. Here, a previously unreported neuronal projection from the dorsal hippocampus (dHPC) to the zona incerta (ZI) involved in the regulation of ML behaviors is identified. Using recombinant adeno-associated virus, the projections to the ZI are surprisingly identified as originating from the dorsal dentate gyrus (DG) and CA1 subregions of the dHPC. Furthermore, projection-specific chemogenetic and optogenetic manipulation reveals that the projections from the dorsal CA1 to the ZI play key roles in the acquisition and consolidation of ML behaviors, whereas the projections from the dorsal DG to the ZI mediate the retrieval/retention of ML behaviors. The results reveal new projections from the dorsal DG and dorsal CA1 to the ZI involved in the regulation of ML and provide insight into the stages over which this regulation occurs.

Co-effect of Demand-control-support model and effort-reward imbalance model on depression risk estimation in humans: findings from Henan Province of China.

OBJECTIVE: To investigate the co-effect of Demand-control-support (DCS) model and Effort-reward Imbalance (ERI) model on the risk estimation of depression in humans in comparison with the effects when they are used respectively. METHODS: A total of 3 632 males and 1 706 females from 13 factories and companies in Henan province were recruited in this cross-sectional study. Perceived job stress was evaluated with the Job Content Questionnaire and Effort-Reward Imbalance Questionnaire (Chinese version). Depressive symptoms were assessed by using the Center for Epidemiological Studies Depression Scale (CES-D). RESULTS: DC (demands/job control ratio) and ERI were shown to be independently associated with depressive symptoms. The outcome of low social support and overcommitment were similar. High DC and low social support (SS), high ERI and high overcommitment, and high DC and high ERI posed greater risks of depressive symptoms than each of them did alone. ERI model and SS model seem to be effective in estimating the risk of depressive symptoms if they are used respectively. CONCLUSION: The DC had better performance when it was used in combination with low SS. The effect on physical demands was better than on psychological demands. The combination of DCS and ERI models could improve the risk estimate of depressive symptoms in humans.

[Evidence-based study of chromate exposed workers' health surveillance indexes].

OBJECTIVE: The health surveillance proposal for chromate exposed workers was provided and analyzed on the evidence-based study and then to be improved. METHOD: Firstly, the related literatures were searched about liver damage, micronuclei, urinary chromium and hexavalent chromium exposure in Evidence Based Medicine Reviews such as Cochran library, OVID Medline, Web of knowledge in December 2011; and then, these literatures were reviewed in according to inclusion and exclusion criteria; 22 articles totally were retrieved, evaluated and classified in according to the grading standard by Oxford Centre for Evidence-based Medicine.Finally, field epidemiological investigation was further adopted to confirm the efficiency and feasibility of this proposal, combined with cost-effectiveness analysis:the ratio of total cost divided survival years was used to express the cost-effectiveness. RESULT: Only the glutamic pyruvic transaminase test could not reflect liver damage caused by chromate exposure well; Urinary chromium correlated well with the index reflecting body damage caused by chromate exposure; Binucleated cells micronucleus index in peripheral blood lymphocyte could reflect the genetic damage caused by chromate exposure. As for health economic evaluation of chromate lung cancer, the value of cost/effectiveness was ¥42 321.61 per year that was far below the value of common people (¥252 868.97 per year) . CONCLUSION: It was suggested that serum glutamic pyruvic transaminase test should be replaced by liver function test, urinary chromium should be classified as a compulsory index and binucleated cells micronucleus index in peripheral blood lymphocyte should be supplied as a recommended index.

[Cloning and sequence analysis of AGO1 gene in Panax ginseng].

Argonaute 1 (AGO1) is a core component of the RNA-induced silencing complex (RISC) which plays a crucial role in small RNA-mediated gene silencing. AGO1 gene has been characterized in various plants, such as Arabidopsis and rice. However, there is no information about AGO1 in the medicinal plant species, Panax ginseng. Using the rapid amplification of cDNA ends technology (RACE), we cloned full-length PgAGO1 cDNA from Panax ginseng. It is 3 776 bp in length, including 204 bp of 5' UTR, 254 bp of 3' UTR, and 3 318 bp of ORF encoding 1106 amino acids. The molecular weight (MW) and theroretical isoelectric point (pI) of the deduced PgAGO1 protein is 122.22 kDa and 9.71, respectively. PgAGO1 shares 91.72% similarity with Arabidopsis AtAGO1 and contains three consered domains, including DUF1785, PAZ and Piwi, suggesting it is an authentic AGO. PgAGO1 was expressed in all of the tissues analyzed with the highest level in flowers and the lowest level in roots. The results provide useful information for further elucidating the function of AGO1 in Panax ginseng.

Rapamycin Inhibits Osteoclastogenesis and Prevents LPS-Induced Alveolar Bone Loss by Oxidative Stress Suppression.

Periodontitis is a progressive inflammatory skeletal disease characterized by periodontal tissue destruction, alveolar bone resorption, and tooth loss. Chronic inflammatory response and excessive osteoclastogenesis play essential roles in periodontitis progression. Unfortunately, the pathogenesis that contributes to periodontitis remains unclear. As a specific inhibitor of the mTOR (mammalian/mechanistic target of rapamycin) signaling pathway and the most common autophagy activator, rapamycin plays a vital role in regulating various cellular processes. The present study investigated the effects of rapamycin on osteoclast (OC) formation in vitro and its effects on the rat periodontitis model. The results showed that rapamycin inhibited OC formation in a dose-dependent manner by up-regulating the Nrf2/GCLC signaling pathway, thus suppressing the intracellular redox status, as measured by 2',7'-dichlorofluorescein diacetate and MitoSOX. In addition, rather than simply increasing the autophagosome formation, rapamycin increased the autophagy flux during OC formation. Importantly, the anti-oxidative effect of rapamycin was regulated by an increase in autophagy flux, which could be attenuated by blocking autophagy with bafilomycin A1. In line with the in vitro results, rapamycin treatment attenuated alveolar bone resorption in rats with lipopolysaccharide-induced periodontitis in a dose-dependent manner, as assessed by micro-computed tomography, hematoxylin-eosin staining, and tartrate-resistant acid phosphatase staining. Besides, high-dose rapamycin treatment could reduce the serum levels of proinflammatory factors and oxidative stress in periodontitis rats. In conclusion, this study expanded our understanding of rapamycin's role in OC formation and protection from inflammatory bone diseases.

Correction to "Rapamycin Inhibits Osteoclastogenesis and Prevents LPS-Induced Alveolar Bone Loss by Oxidative Stress Suppression".

[This corrects the article DOI: 10.1021/acsomega.3c01289.].

Risk factors of low back pain among the Chinese occupational population: a case-control study.

OBJECTIVE: To explore the risk factors of low back pain among the Chinese occupational population in several major industries. METHODS: A total of 7200 subjects (3600 cases and 3600 controls) were randomly sampled from a cross-sectional study, and they were investigated for individual and occupational factors of low back pain. The potential risk factors were first selected by using chi-square tests. Secondly, collinearity diagnosis proceeded by using the Kendall's rank correlation. Finally, binary logistic regression model was used for multi-factor analysis. RESULTS: Collinearity diagnosis showed that there was a severe collinearity problem among the potential risk factors of low back pain. Logistic regression model included 20 variables with statistical significance. Bending neck forward or holding neck in a forward posture for long periods (OR=1.408) was the most important risk factor inducing low back pain in this study, followed by bending heavily with the trunk (OR=1.402), carrying out identical work almost for the whole day (OR=1.340). Additionally, sufficient normal break was a protective factor of low back pain. CONCLUSION: Low back pain among the Chinese occupational population was associated with body height, occupation, work organization, physical work, working posture, and others. All these risk factors could be regarded as the indicators of low back pain, and some relevant preventive measures should be taken to reduce low back pain risk.

[Effects of acute hypobaric hypoxia and exhaustive exercise on AMP-activated protein kinase phosphorylation in rat skeletal muscle].

The present study was aimed to explore the changes of phosphorylated AMP-activated protein kinase (pAMPK) level in skeletal muscle after exposure to acute hypobaric hypoxia and exhaustive exercise. Thirty-two male Sprague-Dawley (SD) rats were randomly divided into sea level and high altitude groups. The rats in high altitude group were submitted to simulated 5 000 m of high altitude in a hypobaric chamber for 24 h, and sea level group was maintained at normal conditions. All the rats were subjected to exhaustive swimming exercise. The exhaustion time was recorded. Before and after the exercise, blood lactate and glycogen content in skeletal muscle were determined; AMPK and pAMPK levels in skeletal muscle were detected by Western blot. The results showed that the exhaustion time was significantly decreased after exposure to high altitude. At the moment of exhaustion, high altitude group had lower blood lactate concentration and higher surplus glycogen content in gastrocnemius compared with sea level group. Exhaustive exercise significantly increased the pAMPK/AMPK ratio in rat skeletal muscles from both sea level and high altitude groups. However, high altitude group showed lower pAMPK/AMPK ratio after exhaustion compared to sea level group. These results suggest that, after exposure to acute hypobaric hypoxia, the decrement in exercise capacity may not be due to running out of glycogen, accumulation of lactate or disturbance in energy status in skeletal muscle.

[Dynamic observation of pulmonary ventilation function in workers contacting chromate].

OBJECTIVE: To explore changes of pulmonary ventilation function of chromate exposed workers. METHODS: Ninety-five chromate exposed workers were used as exposure group, and forty-two workers without chromate exposure as control group. Pulmonary ventilation function was performed two times in the winter of 2010 and 2011 respectively in one chromate manufactured factory in Henan Province. RESULTS: In 2010, pulmonary ventilation function of chromate exposed group compared with the control group, forced vital capacity [FVC, (75.38±15.23) L vs. (83.99±26.52)L], forced expiratory volume in one second [FEV1,(82.13±16.51)L vs.(91.24±30.03)L], FEV1/FVC(112.10±13.23 vs. 116.18±11.32), peak expiratory flow [PEF,(74.31±28.09) L/s vs.(78.13±28.34)L/s], maximal expiratory flow [MEF,(101.23±46.37) L/s vs. (110.02±41.40)L/s], maximum ventilation volume [MVV,(90.82± 16.89)L/min vs. (99.95±22.61)L/min]were significantly decreased(P<0.05). In 2011, pulmonary ventilation function of chromate exposed group compared with the control group, FVC[(72.34±14.18)L vs.(81.01±20.79)L], FEV1[(76.04±16.20)L vs.(86.71±24.53)L], FEV1/FVC(109.10±16.18 vs.114.08±10.79), PEF[(71.35±24.87 )L/s vs.(75.36±20.67)L/s], MEF[(96.51±30.17)L/s vs.(107.11±34.81)L/s], MVV[(84.85±21.22)L/min vs. (96.77±22.63)L/min] were also significantly decreased(P<0.05). 2011 compared with 2010, pulmonary ventilation function of chromate exposed group FEV1[(76.04±16.20)L vs.( 82.13±16.51)L], MEF[(96.51±30.17)L/s vs. (101.23±46.37)L/s], MVV[(84.85±21.22)L/min vs. (90.82±16.89)L/min] were significantly decreased(P<0.05). Comparing the classification and category of pulmonary dysfunction based on FVC, FEV1, FVC/ FEV1, no difference was found for classification between the two groups and the category of pulmonary dysfunction almost belongs to limit type, which did not change with exposed time. CONCLUSION: Chronic chromate exposure can cause significant effects on pulmonary function of the workers, and the types of work in production can affect the results.

[The epidemiological characteristics and correlated factors of daily hassles for thermal power plant workers].

OBJECTIVE: This study aimed to investigate the epidemiological characteristics and correlated factors of daily hassles among thermal power plant workers. METHODS: A mass screening of daily hassles and correlated factors was conducted on 498 workers from a thermal power plant in Zhengzhou in July, 2008. The questionnaires included Daily Hassles Questionnaires, Work Roles Questionnaires, Job Content Questionnaires (Chinese version), Effort-Reward Imbalance (Chinese version), Work Locus of Control Scale and Type A Behavior Scale, with content covering demographic characters and occupational stress correlated factors among subjects. The daily hassles was divided into lower level and higher level according to scores, and the epidemiological characteristics and correlated factors of daily hassles were analyzed. RESULTS: A total of 446 qualified questionnaires were obtained, effective response rate was 89.6% (446/498). For respondents, the age was (36.96 ± 6.49) years old, working length of the current job was (12.05 ± 7.54) years, the daily hassles scores was (9.01 ± 2.50), and the prevalence rate of the higher level of daily hassles was 34.1% (152/446). The multiple non-conditional logistic regression analysis showed 5-14 years' working length of current job (OR = 0.451, 95%CI: 0.225 - 0.904), average income > 3000 yuan(OR = 0.372, 95%CI: 0.202 - 0.684), reward (OR = 0.557, 95%CI: 0.325 - 0.954) and coping strategy (OR = 0.552, 95%CI: 0.330 - 0.925) were negatively correlated with daily hassles, and shift-work (OR = 1.887, 95%CI: 1.108 - 3.215), effort (OR = 2.053, 95%CI: 1.198 - 3.519), psychological demand (OR = 1.797, 95%CI: 1.049 - 3.078), negative affectivity (OR = 3.421, 95%CI: 2.065 - 5.668) were positively correlated with daily hassles. CONCLUSION: The prevalence rate of the higher level of daily hassles was considerable high for thermal power plant workers. Its negative correlated factors included 5 - 14 years' working length of the current job, average income > 3000 yuan, reward and coping strategy and its positive corelated factors included shift-work, effort, psychological demand and negative affectivity.

[Effect of occupational combined exposure of chromium and iron on erythrocyte metabolism].

OBJECTIVE: To investigate the effect of combined occupational exposure of chromium and iron on erythrocyte metabolism, and the possible mechanism. METHODS: A total of 115 chromate production workers were selected in a chemical factory of Jinan as exposure group, Dec, 2008, and 60 healthy residents from a community which was far away from the factory were enrolled as control group. Environmental concentrations of chromium and iron were collected by filter membrane sampling and determined. The peripheral blood of subjects were collected for determination of chromium, iron, copper in whole blood and folate, vitamin B12 in serum, mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) and correlation analysis was conducted. RESULTS: The median (quartile interval) concentration of air-chromium and air-iron in workplace were 9.0 (10.5) and 11.2 (10.1) µg/m³, respectively, which were significantly higher than that of the control (0.1 (0.1) and 7.2 (2.5) µg/m³) (all P values < 0.01). Blood-chromium and blood-iron of the exposed group were 15.5 (14.1) µg/L and (895.1 ± 90.2) mg/L, which were significantly higher than the counterpart of the control (3.6(2.0) µg/L, (563.7 ± 49.3) mg/L) (all P values < 0.01). Serum folate ((6.9 ± 2.5) µg/L), serum vitamin B12 ((396.4 ± 177.0) µg/L) and blood copper ((777.6 ± 103.5) µg/L) of the exposed group were all significantly lower comparing to the control group ((558.0 ± 330.8), (8.1 ± 3.8), (812.1 ± 94.6) µg/L) (all P values < 0.05). The relationships between blood chromium and serum folate, serum vitamin B12 were statistical significant (r = -0.319 and -0.293, P < 0.01). Both serum vitamin B12 and blood copper correlated with mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) (r = -0.223, -0.242, -0.261, -0.292, all P values < 0.01). CONCLUSION: Combined chromium and iron exposure existed in the workplace. Adverse effect of Chromium on human erythrocyte may via folate and vitamin B12 metabolism, while iron may via copper metabolism.