ObjectivesWe investigated the effects of fatigue on NK cell function and lymphocyte subpopulations in nurses performing shift work using a longitudinal design. Methods: Fifty-seven female nurses ...engaged in shift work at a hospital in Japan were selected for our study cohort. The hospital used a counterclockwise rotating three-shift system. Night shifts followed day shifts after a seven-hour interval. Immune parameters measured at the beginning of the day shift through to the end of the night shift were compared between two groups stratified by their level of fatigue. Statistical differences were evaluated after adjusting for baseline immune values and other demographic features. Results: Subjective feelings of fatigue increased progressively from the beginning of day shifts to the end of night shifts. From the beginning of day shifts to the end of night shifts, NK cell activity and CD16+CD56+ lymphocytes decreased, while CD3+ and CD4+ lymphocytes increased. The group with the greater increase in fatigue showed a larger decrease in NK cell activity and a larger increase in CD4+ lymphocytes when compared with the group reporting less fatigue. These findings did not change after adjusting for demographic factors and sleep hours. Conclusion: Our data suggest that shift work has deleterious effects on NK cell function and that the effects depend on the degree of fatigue. Proper management of shift work may lessen fatigue in workers and also ameliorate many health problems experienced by shift workers.
To clarify the influence of dioxin exposure on brain morphometry, the present study investigated associations between dioxin exposure at high levels and brain structural irregularities in 32 ...Vietnamese men. Two exposure markers were used: blood dioxin levels, as a marker of exposure in adulthood, and perinatal dioxin exposure, estimated by maternal residency in a dioxin-contaminated area during pregnancy. All subjects underwent brain magnetic resonance imaging (MRI) scans. We analyzed correlations between regional gray matter volumes and blood dioxin levels, and compared regional volumes between men with and without perinatal dioxin exposure using the voxel-based morphometry (VBM) tool from Statistical Parametric Mapping 12 (SPM12). Blood 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was associated with low volume of the medial temporal pole and fusiform gyrus. Toxic equivalency (TEQ)-PCDDs were correlated with low medial temporal pole volume. However, 1,2,3,4,7,8-HxCDD was associated with high middle frontal gyrus and cerebellum volume. In men with perinatal dioxin exposure, the left inferior frontal gyrus pars orbitalis volume was significantly lower than in those without perinatal exposure. These results suggest that dioxin exposure during the perinatal period and in adulthood may alter regional brain volume, which might lead to cognitive deficits and unusual social emotional behavior in Vietnamese men living in dioxin-contaminated areas.
Objective
Regulator of calcineurin 1 (RCAN1) controls plasticity of the nervous system and depressive conditions by regulating brain-derived neurotropic factor (BDNF) and plays a crucial role in ...neural and cardiac pathways. The apolipoprotein E gene (ApoE) is a robust risk factor for progression of Alzheimer’s disease. A fatty diet is considered detrimental for metabolic disorders, such as obesity and cardiovascular diseases.
Methods
We examined the neuronal and cardiac protective roles of RCAN1 in ApoE−/− mice that were fed a high- or low-fat diet with and without voluntary movement for 3 months. Organ weights, laboratory data, histology, RNA expression, and behavior were examined.
Results
A high-fat diet with exercise improved depressive function, as examined by the forced swimming test, and RCAN1 mRNA expression was induced in the hippocampus. A low-fat diet with exercise resulted in a reduced body weight, higher heart weight/body weight ratio, and lower circulating triglyceride levels compared with a low-fat diet without exercise. RCAN1 mRNA expression was increased in cardiomyocytes in ApoE−/− mice.
Conclusions
The combination of a high-fat diet and exercise might reduce depressive function, whereas a low-fat diet with exercise leads to cardioprotection. Induction of RCAN1 expression might affect neuroplasticity and cardiac function.
Very few studies have investigated the dose–response relationship between external cadmium (Cd) exposure and mortality. We aim to investigate the relationship between lifetime Cd intake (LCd) and ...mortality in the Cd-polluted Kakehashi River basin in Japan. Mortality risk ratios for a unit of increase of LCd and urinary Cd were analyzed using Cox’s proportional model. LCd was estimated based on residency and Cd in rice produced in their living areas. In men, mortality for all causes was significantly increased for a 10-μg/g Cr increase in urinary Cd, but not for a 1-g increase in LCd. In women, mortality risks for all causes and renal diseases, particularly renal failure, were significantly increased for a 10-μg/g Cr increase in urinary Cd. Similarly, mortality risks for renal diseases and renal failure were significantly increased for a 1-g increase of LCd in women. Comparing the contribution of two exposure markers to increased mortality in women, LCd was more effective for increasing mortality risks for renal diseases and renal failure, while urinary Cd contributed more to increased mortality risk for all causes. LCd may show a better dose–response relationship with mortality risk for renal diseases in women.
Excess female births (lower sex ratio at birth) associated with paternal exposure to 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD) have been reported in Italy. However, no significant effects of maternal ...TCDD exposure on the sex ratio were reported. We investigated the effects of maternal TCDD exposure and the toxic equivalent quantity of polychlorinated dibenzo-p-dioxins/dibenzofurans (TEQ-PCDD/Fs) on the sex ratio at birth in 576 Vietnamese infants from three birth cohorts. TCDD and TEQ-PCDD/Fs in breast milk were stratified (low, mild, moderate, and high) as maternal exposure markers. Logistic regression analysis was used to investigate associations between female birth and dioxin exposure groups after adjusting for confounders. In sprayed and unsprayed areas, adjusted odds ratios (ORs) of female birth (reference: low-TCDD group) were 2.11 in the moderate-TCDD group and 2.77 in the high-TCDD group, which were significantly associated with increased TCDD exposure. In sprayed areas, a significantly increased OR in the high-TCDD group was observed. No significant associations, however, were found between having a girl and TEQ-PCDD/F levels. These results suggest that maternal TCDD exposure may alter the sex ratio at birth among Vietnamese residents of areas with high dioxin contamination.
Background Several studies have suggested that the exposure to cadmium （Cd） increased mortalities from renal diseases, cardiovascular diseases and malignant neoplasm, including lung cancer and ...prostate cancer among inhabitants living in Cd-polluted areas and factory workers. This study aimed to assess the influence of environmental exposure to Cd on long term outcome of inhabitants living in an area polluted by Cd. Methods A 22-year follow-up study was conducted with 3119 inhabitants （1403 men and 1716 women） living in the Cd polluted Kakehashi River basin in Japan. The subjects were divided into 4 groups according to the amount of urinary Cd level （〈3.0 μg/g creatinine （Cr）, 3.0-4.9 μg/g Cr, 5.0-9.9 μg/g Cr, and -〉10.0 μg/g Cr）. Mortality was calculated by the person-years method. Hazards ratios （HR） and 95% confidence intervals （CI） were assessed by the Cox＇s proportional hazard model. Results Compared with urinary Cd 〈3.0 μg/g Cr group, the HR of 5.0-9.9μg/g Cr and 〉10.0 μg/g Cr groups were significantly increased after adjustment for age in both sexes： 1.24 （95% Cl 1.01-1.51） and 1.48 （95% CI 1.17-1.90） for men; 1.64 （95% CI 1.17-2.28） and 1.78 （95% Cl 1.27-2.50） for women. The most frequent cause of death was malignant neoplasm in men and cardiovascular diseases in women. The significant increase in mortality risk for cardiovascular diseases was observed in the subjects with 〉10 μg/g Cr in both sexes： 1.79 for men （95% Cl 1.02-3.12） and 2.38 for women （95% Cl 1.11-5.07）. When the subjects were divided into 2 categories （〈20μg/g Cr and 〉20 μg/g Cr）, the HR of the urinary Cd 〉20 μg/g Cr group for nephritis and nephrosis were 4.82 （95% Cl 1.07-21.61） in men and 7.92 （95% Cl 1.77-35.33） in women, respectively. The significant increase was not observed for malignant neoplasm. Conclusion These results suggest a dose-response relationship between Cd body burden and mortality for cardiovascular diseases, cerebrovascular diseases and nephritis and nephrosis.
In an operation by United States Armed Forces during 1961 to 1971, large quantities of herbicides were sprayed in South Vietnam. These herbicides contained 2,3,7,8-tetrachlorodibenzo-p-dioxin ...(2,3,7,8-tetraCDD), the most toxic congener of dioxins. Several decades after the herbicide spraying ceased, dioxin concentrations in the environment and human remained elevated in the sprayed areas. Breast milk samples from 520 nursing mothers residing in areas including the hot spots as well as the sprayed and unsprayed areas were collected to quantify the levels of dioxins. The total toxic equivalents of 2,3,7,8-substitued PCDDs/PCDFs in breast milk of mothers living in the hot spots, and the sprayed and unsprayed areas were 14.10 pg/g lipid, 10.89 pg/g lipid, and 4.09 pg/g lipid for primiparae and 11.48 pg/g lipid, 7.56 pg/g lipid, and 2.84 pg/g lipid for multiparae, respectively, with significant differences in the values among the three areas. In the hot spots, dioxin levels were highly correlated with the residency of mothers after adjustment for their age and parity.
Large amounts of herbicides containing polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) were sprayed in South Vietnam during the Vietnam War. Levels of PCDD/Fs in the environment of ...South Vietnam remained high even 40 years later. A total of 861 breast milk samples (597 from three areas sprayed with herbicides, Quang Tri, Da Nang, and Bien Hoa, and 264 from three unsprayed areas in North Vietnam) were collected between 2007 and 2015 and the PCDD/F concentrations in the samples were determined. Levels of TEQ-PCDD/Fs and 17 PCDD/F congeners were higher in the sprayed area samples than the unsprayed area samples. We found particular PCDD/F congener patterns for different areas. High tetrachlorodibenzo-p-dioxin (TCDD) concentrations were found in Bien Hoa, high TCDD and 1,2,3,6,7,8-hexadibenzo-p-dioxin concentrations were found in Da Nang, and high 1,2,3,4,6,7,8-heptadibenzo-p-dioxin concentrations were found in Quan Tri. High 1,2,3,4,7,8-hexadibenzofuran and 1,2,3,4,6,7,8-heptadibenzofuran concentrations were also found in Da Nang and Quang Tri. However, breast feeding may have caused associations between the TCDD and polychlorinated dibenzofuran congener concentrations. Advanced statistical analysis will need to be performed in future to assess the characteristic PCDD/F congener profiles in breast milk samples from areas of Vietnam previously sprayed with herbicides.
We investigated the biological half-life of the urinary cadmium concentration (U-Cd) based on a 24-year follow-up study after cessation of cadmium exposure in a cadmium-polluted area. Spot urine ...samples were obtained from all inhabitants in this area in 1979, 1986, 1991, 1999 and 2003. Biological half-life was calculated in the inhabitants whose U-Cd was more than 5 μg l−1 (9 men and 12 women) or 5 μg g−1 creatinine (9 men and 19 women) using a one-compartment model. The estimated half-life and 95% confidence intervals were 13.6 years (9.0-28.2 years) and 13.9 years (9.6-25.6 years) for unadjusted U-Cd in men and women, respectively. For creatinine-adjusted U-Cd, they were 14.2 years (11.2-19.4 years) and 23.5 years (17.7-35.0 years) in men and women, respectively. The biological half-lives of U-Cd obtained in this study were identical with the values of total body burden determined by a different method.
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