SummaryThe urinary concentrations of 8-isoprostane and 8-hydroxy-2'-deoxyguanosine (8-OHdG), which are biomarkers of oxidative stress, were measured in 677 Japanese people without any diseases, and their correlations with lifestyle facotrs, lifestyle-related blood biochemical parameters, and dietary intake of antioxidative vitamins were investigated. The mean urinary concentration of 8-isoprostane and 8-OHdG was 0.58 ng/mg creatinine and 8.43 ng/mg creatinine, respectively. Mean urinary 8-isoprostane was significantly different in terms of age, gender, smoking and alcohol consumption but not different in terms of body mass index (BMI) and exercise. By multiple regression analysis, urinary 8-isoprostane was significantly influenced by smoking and age. On the other hand, mean urinary 8-OHdG showed differences only by age group. Multiple regression analysis revealed that urinary 8-OHdG was significantly influenced by age, smoking, body weight, levels of high-sensitivity Creactive protein (Hs-CRP) and low density lipoprotein-cholesterol in females, although it was significantly influenced by body weight in males. The present study shows that urinary 8-isoprostane is associated with lipid peroxidation related-lifestyles such as smoking, and urinary 8-OHdG is associated with arteriosclerosis related-factors such as Hs-CRP. Our findings suggest that 8-isoprostane and 8-OHdG appear to be prospective biomarkers for early prediction of lifestyle related-disease risk at the population level.

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Changes in the expression of arginase and their association with nitrosative stress were investigated using an asthmatic model previously established in NC/Nga mice with mite extract. Mite crude extract (100 microg/day) from Dermatophagoides farinae was administered intranasally for 5 consecutive days (day 0-4), and a single challenge was performed on day 11. On day 12, upregulation of the mRNA expression of inducible types of nitric oxide synthase (iNOS) and increases in immunohistochemical staining for iNOS and nitrotyrosine were observed. However, the level of nitrite + nitrate was unchanged. An increase in enzymatic activity, upregulation of mRNA expression, and immunostaining for arginase I was detected in the lung tissue and serum. Moreover, increases in both arginase I and II were revealed by immunoblotting. Goblet cell hyperplasia in bronchial epithelial cells and increasing collagen synthesis around the bronchus were also observed. These results suggested that an increase in arginase may lead to decreased availability of arginine for nitric oxide synthase and may contribute to the remodeling of the lung.

The purpose of this study was to assess whether workplace bullying mediates between job strain, evaluated by the job demand-control model, and symptoms of depression and sleep disturbance. Methods: The subjects in this cross-sectional study were recruited from all the workers (N=2,634) at 50 organizations in Japan. Due to missing data, the numbers of subjects included in the analyses varied from 1,646 to 2,062 (response rates varied from 62.5% to 78.2%). Job strain and workplace social support, workplace bullying, depression, and sleep disturbance were assessed using the Japanese versions of the Job C o n t e n t Q u e s t i o n n a i r e , t h e N e g a t i v e A c t s Questionnaire, the Center for Epidemiologic Studies Depression Scale, and the Pittsburgh Sleep Quality Index, respectively. Mediation analysis followed the approach outlined by Baron and Kenny. We quantitatively estimated the mediation effects and tested their significance after adjustment for various combinations of demographic variables and workplace social support. Results: Total effects of job strain index on depression or sleep disturbance were all positive and significant (p<0.05) in both genders. Mediation effects of workplace bullying were also all positive and significant (p<0.05) in both genders. Even after adjustment for workplace social support, the mediation effects were decreased, especially in women, but remained significant (p<0.05). Conclusions: Workplace bullying seems to play important roles in the relationships of job strain with depression or sleep disturbance in both genders. (J Occup Health 2010; 52: 367-374)

In this study, the authors assessed gender differences between the relationships of self-efficacy and the internal health locus of control with compliance in hemodialysis patients. Using a self-efficacy scale for health-related behavior and the Japanese version of the Health Locus of Control Scale, the authors studied individuals who had been regularly undergoing hemodialysis for longer than 1 year. Blood urea nitrogen, serum potassium, and interdialytic weight gain were used to measure compliance. In men, self-efficacy and the internal health locus of control were negatively correlated with all compliance measures. In women, all the correlations were positive, except for that between self-efficacy and interdialytic weight gain. The authors constructed regression lines for the significant interactions. On the basis of blood urea nitrogen or serum potassium levels, the authors found that female patients who had higher self-efficacy or internal health locus of control were less compliant. The decrease of interdialytic weight gain accompanying increased self-efficacy was more significant in men than it was in women.