Li Liu

Dalian University of Technology, Lü-ta-shih, Liaoning, China

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Publications (23)62.65 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: AimTo explore the factors associated with burnout among female hospital nurses in China.Background Burnout has been a major concern in the field of occupational health, and yet there has been little research exploring the factors related to burnout among Chinese nurses. Exploring the factors associated with burnout is important in improving nurses’ health and the quality of health care services in China.Methods The study population consisted of 1845 female hospital nurses in the Liaoning Province of China. Burnout was measured using the Chinese version of the Maslach Burnout Inventory – General Survey; occupational stress was measured using the Chinese versions of the Job Content Questionnaire and Effort–Reward Imbalance Questionnaire. A general linear regression model was applied to analyse the factors associated with burnout.ResultsMean scores (±SD) were 11.74 (7.14) for emotional exhaustion, 7.12 (5.67) for cynicism and 23.34 (9.60) for self-efficacy. Strong extrinsic effort was the most powerful predictor of emotional exhaustion and cynicism; strong psychological job demands were the most robust predictor of low self-efficacy.Conclusion The findings suggest that occupational stress was strongly related to burnout among female hospital nurses in China.Implications for nursing managementOccupational stress was identified as the most robust predictor of burnout among Chinese female hospital nurses. Reducing burnout among nurses working in China may require health education, health promotion and occupational training programmes aimed at improving work situations and reducing occupational stress.
    Journal of Nursing Management 07/2014; 22(5). · 1.45 Impact Factor
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    ABSTRACT: Most studies about informant agreements on adolescents' emotional and behavioral problems have been conducted in Western countries, but this subject has not been well researched in China. The aim of this study was to evaluate the pattern of parent-adolescent agreement on adolescents' problems and its associated factors among school-age adolescents in China. This cross-sectional study was conducted in November and December of 2010. A questionnaire including the Child Behavior Checklist (CBCL), the Youth Self-Report (YSR), the Family Environment Scale (FES) and the characteristics of the child (age and gender), parents (parent-adolescent relationship and parental expectations) and family (family structure, negative life events) was distributed to our study population. A total of 2,199 Chinese adolescents (aged 11-18) from 15 public schools in Liaoning Province, who completed the questionnaire, became our final participants. Pearson's correlation coefficient was used to assess parent-adolescent agreement, and linear regression analysis was used to explore the associated factors of parent-adolescent discrepancies on emotional and behavioral problems. The parent-adolescent agreement on emotional and behavioral problems was high (mean r = 0.6). The scores of YSR were higher than those of CBCL. Factors that increased informant discrepancies on emotional and behavioral problems were boys, older age, the experience of negative life events, low levels of cohesion and organization, and high levels of conflict in the family. A high level of parent-adolescent agreement on emotional and behavioral problems was found. Adolescents reported more problems than their parents did. Family environment is an important factor to be considered when interpreting informant discrepancies on the mental health of Chinese adolescents.
    BMC Psychiatry 04/2014; 14(1):114. · 2.23 Impact Factor
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    ABSTRACT: Besides the rapid growth of economy, unemployment becomes a severe socio-economic problem in China. The huge population base in China makes the unemployed population a tremendously huge number. However, health status of unemployed population was ignored and few studies were conducted to describe the depressive symptoms of unemployed individuals in China. This study aims to examine the relationship between Big five personality and depressive symptoms and the mediating role of self-efficacy in this relationship. This cross-sectional study was performed during the period of July to September 2011. Questionnaires consisting of the Center for Epidemiologic Studies Depression Scale (CES-D), the Big Five Inventory (BFI) and the General Self-efficacy Scale (GSE), as well as demographic factors, were used to collect information of unemployed population. A total of 1,832 individuals (effective response rate: 73.28%) became our subjects. Hierarchical linear regression analyses were performed to explore the mediating role of self-efficacy. The prevalence of depressive symptoms was 67.7% among Chinese unemployed individuals. After adjusting for demographic characteristics, extraversion, agreeableness and conscientiousness were all negatively associated with depressive symptoms whereas neuroticism was positively associated with depressive symptoms. The proportion of mediating effect of self-efficacy in the relationship between extraversion/agreeableness/conscientiousness/neuroticism and depressive symptoms was 25.42%, 10.91%, 32.21% and 36.44%, respectively. Self-efficacy is a mediator in the relationship between extraversion/agreeableness/conscientiousness/neuroticism and depressive symptoms. Self-efficacy partially mediated the relationship between Big five personality and self-efficacy among Chinese unemployed individuals. Interventions that focus on both individuals' personality and self-efficacy may be most successful to reduce depressive symptoms of unemployed individuals.
    BMC Psychiatry 03/2014; 14(1):61. · 2.23 Impact Factor
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    ABSTRACT: The prevalence of depression and anxiety and its associated factors in cervical cancer are not well evaluated in China. Meanwhile, with increasing attention given to positive psychological variables in oncology field, there is a need to conduct a study to explore the integrative effects of positive psychological variables on depression/anxiety so as to provide patients a more holistic cancer care. The aim of this study was to assess the prevalence of depression/anxiety as well as the integrative effects of hope, optimism and general self-efficacy on depression/anxiety among Chinese cervical cancer patients. A multi-centre, cross-sectional study was conducted of consecutive inpatients at the Liaoning Cancer Hospital & Institute and the Shengjing Hospital of China Medical University in Liaoning Province, northeast China. A total of 224 cervical cancer patients eligible for this study completed questionnaires on demographic and clinic variables, Hospital Anxiety and Depression Scale, Herth Hope Index, Life Orientation Scale-Revised, and General Self-Efficacy Scale during February and August 2013. The prevalence of depression and anxiety was 52.2% and 65.6% in cervical cancer patients. The anxiety score was significantly higher in patients at the period of 4-6 months after diagnose and at cancer stage II. Hierarchical regression analyses indicated that hope, optimism and general self-efficacy as a whole accounted for 31.3% variance of depression and 35.6% variance of anxiety. Under standardized estimate (β) sequence, hope, optimism and general self-efficacy significantly associated with depression, respectively; hope and optimism were also significant individual predictors of anxiety. The high prevalence of depression and anxiety among cervical cancer patients should receive more attention in Chinese medical settings. More importantly, efforts to develop the integrated psychosocial interventions are effective and necessary to alleviate depression/anxiety in cervical cancer patients by synthesizing and integrating the individual protective effects of hope, optimism and general self-efficacy.
    PLoS ONE 01/2014; 9(4):e94804. · 3.73 Impact Factor
  • Li Liu, Lie Wang, Jie Chen
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    ABSTRACT: Although underground coal miners are quite susceptible to depressive symptoms due to a highly risky and stressful working environment, few studies have focused on this issue. The purpose of the study was to evaluate the prevalence of depressive symptoms and to explore its associated factors in this population. A cross-sectional survey was conducted in a coal-mining population in northeast China. A set of self-administered questionnaires was distributed to 2500 underground coal miners (1,936 effective respondents). Depressive symptoms, effort-reward imbalance (ERI), overcommitment (OC), perceived physical environment (PPE), work-family conflict (WFC), and some demographic and working characteristics were measured anonymously. The prevalence of depressive symptoms was 62.8%, and the mean level was 20.00 (9.99). Hierarchical linear regression showed that marital status, education, monthly income, and weekly working time were significantly associated with depressive symptoms. A high level of depressive symptoms was significantly associated with high ERI, PPE, WFC, and OC. Accordingly, most Chinese underground coal miners probably have depressive symptoms that are mainly predicted by some occupational psychosocial factors. Efforts should be made to develop strategies to reduce ERI and OC, improve physical working environment, and care for workers' family well-being, thereby mitigating the risk of depression among Chinese underground coal miners.
    BioMed research international. 01/2014; 2014:987305.
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    ABSTRACT: Psychological distress (e.g., depression and anxiety) has been regarded as the main cause of leaving work for people living with HIV/AIDS (PLWHA) in workplaces. This study aims to explore the associations of functional social support (FSS) and psychological capital (PC) with depressive and anxiety symptoms among PLWHA employed full-time. This cross-sectional study was performed in Liaoning, China, during the period of December 2010--April 2011. The Center for Epidemiologic Studies Depression Scale, the Zung Self-Rating Anxiety Scale, the Duke-UNC Functional Social Support Questionnaire, and the Psychological Capital Questionnaire were completed by PLWHA employed full-time. Structural equation modeling was used to test the proposed relationships between variables. Asymptotic and resampling strategies were performed to explore the mediating roles of PC and its components (self-efficacy, hope, optimism, resilience). Of 320 participants surveyed, 66.3% had depressive symptoms, and 45.6% had anxiety symptoms. Significant negative associations of FSS and PC with depressive and anxiety symptoms were revealed. PC (a*b = -0.209, BCa 95% CI: -0.293, -0.137, p < 0.05), hope (a*b = -0.103, BCa 95% CI: -0.192, -0.034, p < 0.05), and optimism (a*b = -0.047, BCa 95% CI: -0.106, -0.008, p < 0.05) significantly mediated the association between FSS and depressive symptoms. PC (a*b = -0.151, BCa 95% CI: -0.224, -0.095, p < 0.05) and self-efficacy (a*b = -0.080, BCa 95% CI: -0.158, -0.012, p < 0.05) significantly mediated the FSS-anxiety symptoms association. FSS and PC could help reduce depressive and anxiety symptoms among PLWHA employed full-time. PC fully mediates the associations of FSS with depressive and anxiety symptoms. In addition to enhancing FSS, PC development could be included in the prevention and treatment strategies for depressive and anxiety symptoms targeted at PLWHA employed full-time.
    BMC Psychiatry 12/2013; 13(1):324. · 2.23 Impact Factor
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    ABSTRACT: Burnout has been a major concern in the field of occupational health. However, there is a paucity of research exploring the factors related to burnout among Chinese doctors. Investigation of these factors is important to improve the health of doctors and the quality of healthcare services in China. The study population consisted of 1,618 registered hospital doctors from Liaoning province of China. Burnout was measured using the Chinese version of the Maslach Burnout Inventory-General Survey. Occupational stress was measured using the Chinese versions of the Job Content Questionnaire and the Effort-Reward Imbalance Questionnaire. Data were collected on the respondents' demographic characteristics and work situations. Of the doctors solicited for enrollment, 1,202 returned the completed questionnaire (555 men, 647 women), giving a response rate of 74.3%. A general linear regression model was applied to analyze the factors associated with burnout. The burnout mean scores were 11.46 (7.51) for emotional exhaustion, 6.93 (5.15) for cynicism, and 24.07 (9.50) for professional efficacy. In descending order of standardized estimates, variables that predicted a high level of emotional exhaustion included: high extrinsic effort, dissatisfaction with doctor-patient relationship, high overcommitment, working >40 h per week, low reward, and high psychological job demands. Variables that predicted a high level of cynicism included: high extrinsic effort, low reward, dissatisfaction with doctor-patient relationship, high overcommitment, low decision authority, low supervisor support, and low skill discretion. Variables that predicted a low perceived professional efficacy included: high psychological job demands, low coworker support, high extrinsic effort, low decision authority, low reward, and dissatisfaction with doctor-patient relationship. These findings suggest that occupational stress is strongly related to burnout among hospital doctors in China. Strategies that aim to improve work situations and decrease occupational stress are necessary to reduce burnout, including health education, health promotion, and occupational training programs.
    BMC Public Health 08/2013; 13(1):786. · 2.08 Impact Factor
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    ABSTRACT: A lot of empirical studies have been conducted to evaluate the prevalence of depression and anxiety among Chinese adults with cancer. We aimed to conduct a meta-analysis in order to evaluate the prevalence and odds ratios of depression and anxiety in Chinese adults with cancer compared with those without. The three most comprehensive computerized Chinese academic databases-CNKI, Wangfang and Vip databases-were systematically screened through September 2012. PubMed and Web of Science (SCIE) were also searched from their inception until September 2012 without language restrictions, and an internet search was also used. Case--control studies assessing the prevalence of depression and anxiety among Chinese adults with cancer were analyzed. Study selection and appraisal were conducted independently by three authors. The non-weighted prevalence, pooled random-effects estimates of odds ratio (OR) and 95% confidence intervals (CI) were all calculated. Seventeen eligible studies with a total of 3497 subjects were included. The prevalence of depression and anxiety were significantly higher in adults with cancer compared with those without (Depression: 54.90% vs. 17.50%, OR = 7.85, 95%CI = 5.56-11.07, P = 0.000; Anxiety: 49.69% vs. 18.37%, OR = 6.46, 95%CI = 4.36-9.55, P = 0.000), the same situation was also observed in subgroup of control groups, assessment methods and cancer types. Although no difference of depression was observed in studies utilizing clinical diagnosis compared with self-report, the OR of anxiety in adults with cancer compared with those without was higher in studies utilizing clinical diagnosis (OR = 8.42, 95%CI = 4.83-14.70) than self-reports (OR = 5.83, 95%CI = 3.64-9.34). The ORs of depression and anxiety in cancer patients compared with disease group (Depression: OR = 6.03, 95%CI = 4.23-8.61; Anxiety: OR = 4.40, 95%CI = 3.05-6.36) were lower than in those compared with normal group (Depression: OR = 13.58, 95%CI = 6.26-29.46; Anxiety: OR = 15.47, 95%CI = 10.00-23.95). We identified high prevalence rates of depression and anxiety among Chinese adults with cancer. The findings support that the prevalence of depression and anxiety among adults with cancer should receive more attention in Chinese medical settings.
    BMC Cancer 08/2013; 13(1):393. · 3.33 Impact Factor
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    ABSTRACT: OBJECTIVES: Chinese correctional officers (COs) consist of frontline COs in direct contact with the prisoners and non-frontline COs (including administrative staff and professionals). Male COs compose the majority of Chinese COs, especially for frontline COs. Although they are quite susceptible to depressive symptoms due to highly risky and stressful working environment, few studies focus on this issue. This study aimed to evaluate the prevalence of depressive symptoms and to explore its associated factors among Chinese male frontline and non-frontline COs. METHODS: This cross-sectional study was performed during the period of March/April 2011. The study population comprised of 1,900 male COs in four male prisons in a province of northeast China. A questionnaire including the Center for Epidemiological Studies Depression Scale, demographic factors, work conditions, effort-reward imbalance questionnaire was distributed to these COs. A total of 1,494 effective respondents became our subjects (981 frontline COs and 513 non-frontline COs). Frontline and non-frontline COs were analyzed separately. RESULTS: Approximately 61.4 % of Chinese male COs had depressive symptoms (63.5 % in frontline COs and 57.3 % in non-frontline COs). Multivariate logistic analyses showed that effort-reward ratio, overcommitment, chronic disease, and threat perception were associated with depressive symptoms in frontline and non-frontline COs, whereas weekly work time had an effect only in frontline COs. CONCLUSIONS: Chinese male COs, especially frontline COs, might have high-level prevalence of depressive symptoms. Moreover, this study had identified important risk factors that might be important in planning strategies for prevention and intervention of depressive symptoms for Chinese male COs.
    International Archives of Occupational and Environmental Health 04/2013; · 2.10 Impact Factor
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    ABSTRACT: BACKGROUND: Although correctional officers (COs) clearly suffer from depression, positive resources for combating depression have been rarely studied in this population. The purpose of the study was to examine the associations of perceived organizational support (POS) and psychological capital (PsyCap) with depressive symptoms among Chinese COs. METHODS: A cross-sectional survey was conducted in a province of northeast China during March--April 2011. A self-administered questionnaire was distributed to 1900 male COs from four male prisons. Depressive symptoms, POS, and PsyCap (self efficacy, hope, resilience, and optimism) were measured anonymously. A total of 1428 effective respondents with 953 frontline COs (FL-COs) and 475 non-frontline COs (NFL-COs) became our final sample. Hierarchical linear regression was performed to explore the factors associated with depressive symptoms. Asymptotic and resampling strategies were used to examine the mediating roles of PsyCap and its four components. RESULTS: The level of depressive symptoms of FL-COs was significantly higher than that of NFL-COs (t = 2.28, p = 0.023). There were significant negative associations of POS, PsyCap, hope, resilience, and optimism with depressive symptoms among FL-COs. In NFL-COs, POS, PsyCap, and optimism were negatively associated with depressive symptoms. POS was positively associated with PsyCap and its four components among both FL-COs and NFL-COs. For FL-COs, PsyCap (a*b = -0.143, BCa 95% CI: --0.186, --0.103, p < 0.05), resilience (a*b = -0.052, BCa 95% CI: --0.090, --0.017, p < 0.05), and optimism (a*b = -0.053, BCa 95% CI: --0.090, --0.016, p < 0.05) significantly mediated the association between POS and depressive symptoms. For NFL-COs, PsyCap (a*b = -0.126, BCa 95% CI: --0.186, --0.065, p < 0.05) and optimism (a*b = -0.066, BCa 95% CI: --0.116, --0.008, p < 0.05) significantly mediated the association. CONCLUSIONS: Perceived organizational support and psychological capital could be positive resources for combating depressive symptoms in Chinese male COs. Psychological capital and its components (resilience and optimism) partially mediate the association between perceived organizational support and depressive symptoms. Therefore, organizational support and psychological capital investment (especially resilience and optimism) should be included in depression preventions and treatments targeting Chinese male COs.
    BMC Psychiatry 03/2013; 13(1):89. · 2.23 Impact Factor
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    ABSTRACT: Although occupational stress is an identified predictor of depressive symptoms, the mechanism behind the association is not well understood. The purpose of this study was to examine how psychological capital (PsyCap), a positive psychological state, mediates the association between occupational stress and depressive symptoms among Chinese physicians. A cross-sectional survey was conducted in Liaoning Province, China, during September-October 2010. Self-administered questionnaires including items on depressive symptoms assessed by the Center for Epidemiologic Studies Depression Scale, occupational stress assessed by the effort-reward imbalance scale and PsyCap estimated by a 24-item Psychological Capital Questionnaire, together with age, gender, marital status and education were distributed to 1300 physicians employed in large general hospitals. The final sample consisted of 998 participants. Asymptotic and resampling strategies were used to examine how PsyCap mediates the association between occupational stress and depressive symptoms. Both the effort/reward ratio (ERR) and overcommitment were significantly associated with depressive symptoms among male and female physicians. There was a gender difference in the mediating role of PsyCap on the occupational stress-depressive symptoms association. For male physicians, PsyCap did not mediate the association between occupational stress and depressive symptoms. For female physicians, ERR and overcommitment were negatively associated with PsyCap, and PsyCap was negatively associated with depressive symptoms. As a result, PsyCap significantly mediated the associations of ERR and overcommitment with depressive symptoms. The proportion of PsyCap mediation was 19.07% for ERR, and 24.29% for overcommitment. PsyCap could be a positive resource for combating depressive symptoms in Chinese physicians. In addition to reducing occupational stress, PsyCap development should be included in depression prevention and treatment strategies, especially for female physicians.
    BMC Public Health 03/2012; 12:219. · 2.08 Impact Factor
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    ABSTRACT: The aim of this study was to investigate the relation between work-family conflict and burnout, and the mediating role of psychological capital (PsyCap) in the relation between work-family conflict and burnout, among Chinese doctors. This cross-sectional study was performed during the period of September/October 2010. A questionnaire that comprised work-family conflict assessed by the work-family conflict scale, PsyCap assessed by the PCQ-24 scale and burnout assessed by the Maslach Burnout Inventory-General Survey (MBI-GS), as well as age and gender, was distributed to 1,300 doctors in Liaoning Province, China. A total of 1,011 effective respondents became our final study subjects. Hierarchical linear regression analyses were performed by using SPSS 17.0 to explore the mediating role of PsyCap in the relation between work-family conflict and burnout. Both work interfering family conflict (WIF) and family interfering work conflict (FIW) were positively related with emotional exhaustion and cynicism among both male and females doctors. However, WIF was positively related with professional efficacy only among male doctors, whereas FIW was negatively related with professional efficacy among both male and female doctors. PsyCap partially mediated the relation between WIF and professional efficacy among male doctors and partially mediated the relations of FIW with emotional exhaustion, cynicism and professional efficacy among female doctors. Work-family conflict was associated with burnout among Chinese doctors. PsyCap was a mediator between work-family conflict and burnout. PsyCap might be a positive resource to reduce the negative effect of work-family conflict on burnout of doctors, especially female doctors, in China.
    Journal of Occupational Health 01/2012; 54(3):232-40. · 1.63 Impact Factor
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    ABSTRACT: The toxicity of perfluorooctane sulfonate (PFOS), a persistent organic compound, is of great concern. Several studies have reported that PFOS decreases circulating thyroid hormone (TH) concentrations. However, the mechanisms involved remain to be determined. Female rats were exposed to (1) vehicle; (2) PFOS (0.2, 1.0, and 3.0 mg/kg); (3) propylthiouracil (PTU, 10 mg/kg); or (4) PTU (10 mg/kg) + PFOS (3.0 mg/kg) by gavage once a day for 5 consecutive days. Parameters including contents of total T4 (TT4) and total T3 (TT3) in both serum and bile, serum concentrations of transthyretin and thyroglobulin, as well as transcripts of transporters involved in hepatic uptake and efflux of T4 were determined in control and PFOS-exposed groups. TT4 and TT3 were also analyzed in PTU and PTU + PFOS groups in order to reflect the different hormone effects between PFOS, PTU, and PFOS + PTU. Results showed that serum TT4 and TT3 decreased, while bile TT4 and TT3 remained stable following PFOS exposure. Exposure to 3.0 mg/kg of PFOS significantly enhanced hepatic organic anion transporter OATP2 mRNA expression (1.43 times of control). Treatment with PFOS increased hepatic expression of multidrug resistance--associated protein MRP2, approximately 1.80 and 1.69 times of control in 1.0 and 3.0 mg/kg groups, respectively. Spearman's correlation coefficients revealed that MRP2 mRNA expression correlated well with serum TT4 level (r = -0.528, P = 0.012). Serum thyroglobulin and transthyretin levels remained stable. Serum TT3, bile TT4, and bile TT3 were significantly different between PFOS and PTU groups. No significant differences of TT4 and TT3 in both serum and bile were observed between PTU and PTU + PFOS (P > 0.05). In conclusion, PFOS increased hepatic expression of OAPT2, which could possibly enhance hepatic uptake and metabolism of T4 in rats. PFOS-induced TT4 deficiency is mainly due to the extrathyroidal metabolism of T4, which is probably different from the classic goitrogen, PTU.
    Archives of Toxicology 11/2010; 85(6):613-21. · 5.22 Impact Factor
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    ABSTRACT: A fluorochemical industrial park was built in 2004 in Fuxin, China, for the production of polytetrafluoroethylene (PTFE) and perfluorobutane sulfonate (PFBS). Yet little is known about the distribution of fluorochemicals in the environment and in people living in and around the park. In this study, environmental samples were collected from 22 sites in Fuxin to investigate the extent of perfluorinated compound (PFC) contamination in the environment around the park, and in drinking water from the public water supply system and groundwater in shallow aquifers from private wells near the park. Serum samples were also collected from nonoccupationally exposed residents living in Fuxin to determine the PFC load of local residents. As the dominant contaminant of eight target PFCs, the maximum concentrations of perfluorooctanoic acid (PFOA) in sediment and river water of the River Xi along the industrial park were 48 ng/g dry weight and 668 ng/L, respectively; the highest PFOA concentration in groundwater beneath the park was 524 ng/L; and the PFOA levels in drinking water from the public water supply system ranged between 1.3 and 2.7 ng/L. In human serum, PFOA had the geometric mean at 4.3 ng/mL, ranging from 0.02 to 93 ng/mL. This study serves to document what should be the beginning of a long-term surveillance effort to minimize potential exposure of residents living in Fuxin.
    Environmental Science & Technology 10/2010; 45(19):8075-80. · 5.26 Impact Factor
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    ABSTRACT: Perfluorooctane sulfonate (PFOS) is a persistent and bio-accumulative pollutant ubiquitous in wildlife and humans, which receives many concerns on the fate, transport, distribution, and toxicity. Studies have shown that PFOS-induced neurotoxicity in experimental animals; however, little is known about the potential mechanism of PFOS exposure on the central nervous system (CNS). Ca(2+)/calmodulin-dependent protein kinase IIalpha (CaMKIIalpha), cAMP-response element binding protein (CREB), c-fos, and c-jun, which are important down-stream molecules of calcium signaling in describing neuron cells structure and function in the CNS, were examined in the paper with the purpose to evaluate the effect of PFOS exposure on brain and approach the molecular mechanisms involved in the neurotoxicity induced by PFOS. Adult male Sprague-Dawley rats were administered with PFOS at dosages of 1.7, 5.0, and 15.0 mg/L in drinking water for 91 consecutive days. LC/MS was used for PFOS analysis in brain tissues, and western blot was employed to determine the expression of CaMKIIalpha and pCREB in the isolated cortex and hippocampus. The expression of c-fos and c-jun was detected by real-time reverse transcription polymerase chain reaction. The results showed that the expression of CaMKIIalpha and pCREB exhibits a significant increase in cortex and hippocampus after treatment with PFOS, compared with the control. The transcription factor c-fos was up-regulated in hippocampus, and c-jun was elevated both in cortex and hippocampus in PFOS-treated groups. These results indicated that, at least in part, the neurotoxic effect induced by PFOS is mediated by the Ca(2+)-dependent molecules in calcium signaling.
    Archives of Toxicology 06/2010; 84(6):471-9. · 5.22 Impact Factor
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    ABSTRACT: Perfluorinated compounds (PFCs) have been determined in various matrices within China including water bodies, precipitations, biota and non-occupationally PFCs-exposed populations in recent years, yet little attention has been focused on the distributions of PFCs in urban river sediments from Chinese major metropolises such as Guangzhou and Shanghai so far. In this study, sediment samples of 0-2 cm were collected from 13 sites in the Zhujiang River across Guangzhou and nine sites in the Huangpu River across Shanghai. PFCs analysis on these sediments via high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) system was implemented targeting eight analytes involving perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA) and perfluorotetradecanoic acid (PFTA). According to the analytical results, total concentrations of PFCs ([summation operator]PFCs) in sediments from the Zhujiang River were between 0.09 and 3.6 ng/g dry weight (dw), with PFOS being the dominant PFC contaminant in the river ranged from below LOD to 3.1 ng/g dw; while [summation operator]PFCs in sediments from the Huangpu River were between 0.25 and 1.1 ng/g dw, with PFOA being the main PFC contaminant in the river determined in the levels of 0.20-0.64 ng/g dw. Additionally, an overall decreasing trend of PFCs contaminations with depth was observed in both of two 60 cm sediment cores from the Zhujiang River and the Huangpu River each.
    Chemosphere 06/2010; 80(2):123-30. · 3.14 Impact Factor
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    ABSTRACT: Higher blood levels of perfluorooctane sulfonate (PFOS) in males than the females have been observed in many human biomonitoring studies, which is not well explained yet. The effects of gestation and regular bleeding on blood PFOS level in mice were investigated to evaluate the potential factors that could result in the sex difference. The mice were exposed to PFOS via drinking water at a concentration of 50 mug/l. After 6 weeks of pre-exposure and the gestation period, the blood PFOS concentrations in the gestagenic mice were significantly lower than the control non-gestagenic mice with a ratio of 0.45. Significant lower blood PFOS concentrations in the male mice treated by regular artificial bleeding were observed compared with those from the control male. However, such difference was not observed for the females. The sex difference in the effect of regular artificial bleeding on the blood PFOS level may be caused by the different accumulation and elimination rate in the female and male mice. In addition, the effect of intermittent exposure to PFOS on blood level was evaluated. Each single exposure caused a significant increase in blood PFOS level in both females and males, suggesting the acute exposure to PFOS occurred before the blood sampling, e.g. exposure to PFOS-contaminated foods or drinks, would affect the biomonitoring data to some extent depending on the background blood level. Thus serial blood monitoring is required to obtain accurate body burden.
    The Journal of Toxicological Sciences 06/2010; 35(3):309-16. · 1.38 Impact Factor
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    ABSTRACT: Perfluorooctane sulfonate (PFOS), a persistent and bioaccumulative compound, is widely distributed in the environment. To explore the molecular mechanism of neonatal neurotoxic effects, we evaluated the transcriptional effects of prenatal and neonatal exposure to PFOS in developing rat brain by performing gene expression profiling in the cerebral cortex. Dams received 3.2 mg/kg PFOS in their feed from gestational day 1 (GD1) to weaning (PND 21). Pups then had free access to treated feed until PND 35. Six Illumina RatRef-12 Expression BeadChips were used to identify gene expression changes on postnatal days (PNDs) 1, 7, and 35. Significantly affected genes (P < 0.05) were involved in neuroactive ligand-receptor interaction, calcium signaling pathways, cell communication, long-term potentiation/depression, the cell cycle, and peroxisome proliferator-activated receptor (PPAR) signaling. To compare prenatal and lactational exposure contributions to transcriptional effects, a subset of altered genes obtained from the gene-profile study that represented neurobiological functions was analyzed using RT-PCR in a follow-up cross-foster study lasting from PND1 to 21. Prenatal and postnatal exposure to PFOS caused potential neurotoxicity as demonstrated by developmentally different global transcriptional changes. Prenatal exposure was more effective in altering expression of several genes. Also, transcriptional effects of PFOS exposure on neurodevelopment occurred primarily by disrupting the neuroendocrine system.
    Environmental Science and Technology 02/2010; 44(5):1847-53. · 5.26 Impact Factor
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    ABSTRACT: Perfluorooctane sulfonate (PFOS), an environmentally persistent organic pollutant, has been reported to be transferred to the developing organisms via both placenta and breast milk. A cross-foster model was used to determine whether prenatal or postnatal exposure to PFOS alone can disturb the TH homeostasis in rat pups, and if so, which kind of exposure is a major cause of TH level alteration. Pregnant rats were fed standard laboratory rodent diet containing 0 (control) or 3.2 mg PFOS/kg throughout gestation and lactation period. On the day of birth, litters born to treated and control dams were cross-fostered, resulting in the following groups: unexposed control (CC), pups exposed only prenatally (TC), only postnatally (CT) or both prenatally and postnatally (TT). Serum and liver PFOS concentrations, serum total thyroxine (T4), total triiodothyronine (T3), reverse T3 (rT3) levels, and hepatic expression of genes involved in TH transport, metabolism, and receptors were evaluated in pups at the age of postnatal days (PNDs) 0, 7, 14, 21, or 35. PFOS body burden level in pups in group CT increased, while those in group TC dropped as they aged. Neither total T3 nor rT3 in pups was affected by PFOS exposure. Gestational exposure to PFOS alone (TC) significantly (p < 0.05) decreased T4 level in pups on PNDs 21 and 35, 20.3 and 19.4% lower than the control on the same PND, respectively. Postnatal exposure to PFOS alone (CT) also induced T4 depression on PNDs 21 and 35, 28.6 and 35.9% lower than controls, respectively. No significant difference in T4 level (p > 0.05) was observed between TC and CT on these two time points. None of the selected TH related transcripts was affected by PFOS in pups on PND 0. Only transcript level of transthyretin, TH binding protein, in group TT significantly increased to 150% of the control on PND 21. The results showed that prenatal PFOS exposure and postnatal PFOS exposure induced hypothyroxinemia in rat pups to a similar extent, which suggested that in utero PFOS exposure and postnatal PFOS accumulation, especially though maternal milk, are matters of great concern.
    Environmental Science and Technology 11/2009; 43(21):8416-22. · 5.26 Impact Factor
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    ABSTRACT: Perfluorooctanesulfonate (PFOS) is an environmental contaminant found in human and animal tissues worldwide. The developing nervous system is thought to be particularly sensitive to PFOS by the fact that PFOS can cross blood-brain and placental barriers. Effect of gestational and lactational exposure to PFOS on central nervous system (CNS) in Wistar rats was investigated by the cross-foster model built with PFOS at 0 or 3.2 mg/kg food. Real-time reverse transcription-polymerase chain reaction was employed to evaluate the gene expression of calcium-dependent signaling molecules in rats' hippocampus which are critical to the function of CNS. The expression of calcium-related signaling molecules, such as N-methyl-D-aspartate receptor subtype-2B (NR2B), calmodulin (CaM), Ca2+/calmodulin-dependent kinase II alpha (CaMKIIalpha) and cAMP-response element-binding (CREB) were increased in the PFOS exposure group at postnatal day 1 (PND 1). The decreased NR2B in the prenatal PFOS exposure group, the decreased CaM in the pre-/postnatal PFOS exposure group, the increased CaMKIIalpha in the whole-life PFOS exposure group and the increased CREB in the prenatal/whole-life PFOS exposure group was observed at PND 7. At PND 35, rats exhibited the decreased NR2B in the pre-/postnatal and the whole-life PFOS exposure group, and the decreased CaM in the postnatal PFOS group. The results indicate that perinatal exposure to PFOS during the critical period of development of the brain may have neurotoxic effect on CNS by mediating the molecules of calcium signaling pathway.
    Archives of Toxicology 09/2009; 84(1):71-9. · 5.22 Impact Factor