Thyroglobulin (TG), the primary synthetic product of the thyroid, is the macromolecular precursor of thyroid hormones. TG synthesis, iodination, storage in follicles, and degradation control thyroid hormone formation and secretion into the circulation. Thyrotropin (TSH), via its receptor (TSHR), increases thyroid hormone levels by upregulating expression of the sodium iodide symporter (NIS), thyroid peroxidase (TPO), and TG genes. TSH does this by modulating the expression and activity of several thyroidspecific transcription factors, thyroid transcription factor (TTF)-1, TTF-2, and Pax-8, which coordinately regulate NIS, TPO, TG, and the TSHR. Major histocompatibility complex class I gene expression, which also is regulated by TTF-1 and Pax-8 in the thyroid, is decreased simultaneously. This helps maintain self-tolerance in the face of TSH-increased gene products necessary for thyroid hormone formation. In this report we show that follicular TG counter-regulates TSHincreased, thyroid-specific gene transcription by suppressing expression of the TTF-1, TTF-2, and Pax-8 genes. This decreases expression of the TG, TPO, NIS, and TSHR genes, but increases class I expression. TG acts transcriptionally, targeting, for example, a sequence within 1.15 kb of the 5 f lanking region of TTF-1. TG does not affect ubiquitous transcription factors regulating TG, TPO, NIS, and͞or TSHR gene expression. The inhibitory effect of TG on gene expression is not duplicated by thyroid hormones or iodide and may be mediated by a TG-binding protein on the apical membrane. We hypothesize that TG-initiated, transcriptional regulation of thyroid-restricted genes is a normal, feedback, compensatory mechanism that limits follicular function and contributes to follicular heterogeneity.

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Objective: Although several studies have reported associations of depressive state with specific nutrients and foods, few studies examined the association with dietary patterns in adults. We investigated the association between major dietary patterns and depressive symptoms in Japanese. Methods: Subjects were 521 municipal employees (309 men and 212 women), aged 21-67 years, who participated in a health survey at the time of periodic checkup. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) Scale. Dietary patterns were derived by using principal component analysis of the consumption of 52 food and beverage items, which was assessed by a validated brief diet history questionnaire. Logistic regression analysis was used to estimate odds ratios of depressive symptoms (CES-D X16) with adjustment for potential confounding variables. Results: We identified three dietary patterns. A healthy Japanese dietary pattern characterized by high intakes of vegetables, fruit, mushrooms and soy products was associated with fewer depressive symptoms. The multivariate-adjusted odds ratios (95% confidence intervals) of having depressive symptoms for the lowest through highest tertiles of the healthy Japanese dietary pattern score were 1.00 (reference), 0.99 (0.62-1.59) and 0.44 (0.25-0.78), respectively (P for trend ¼ 0.006). Other dietary patterns were not appreciably associated with depressive symptoms. Conclusions: Our findings suggest that a healthy Japanese dietary pattern may be related to decreased prevalence of depressive status.

Objectives: This study aimed to evaluate the effectiveness of supervised exercise among nurses conducting shift work for health promotion. Methods: A total of 30 healthy female nurses conducting shift work participated in this study and they were randomly assigned to one of the following 2 groups: The supervised exercise group (SG; participants exercised under the supervision of a physical therapist (PT)) and the voluntary exercise group (VG; participants exercised without supervision). The study participants were asked to exercise twice/week for 12 weeks for 24 sessions. The primary outcome was aerobic fitness, and the secondary outcomes were muscle strength, anthropometric data, biochemical parameters, and mental health. We compared all the outcomes before and after the intervention within each group and between both groups at follow-up. Results: Aerobic fitness increased in the SG whereas it decreased in the VG, but these changes were not statistically significant (p=0.053 and 0.073, respectively). However, the between-group difference was significant in the intervention effect (p=0.010). Muscle strength, high-density lipoprotein cholesterol and metabolic profile (high-molecular weight adiponectin), and depressive symptom significantly improved in the SG over time, even though the SG exercised less as compared with the VG. Moreover, significant differences in muscle strength, and low-density lipoprotein cholesterol and reactive oxygen metabolite levels were observed between both groups, and these parameters were better in the SG than in the VG. Conclusions: Our data-suggest the effectiveness of exercise supervised by a PT at the workplace of nurses conducting shift work for health promotion.

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Effect of the Physical Activities in LeisureTime and Commuting to Work on Mental Health: Masanori OHTA, et al. Department of Health Development, University of Occupational and Environmental Health-Although some evidence suggests that exercise may improve mental health status, information regarding the intensity and duration of exercise is incomplete. The purpose of this study was to elucidate the association between physical activities in both leisure time and commuting to work and mental health. A questionnaire survey was conducted at three municipal offices in Japan. A total of 670 men and women completed the questionnaire. Mental health status was assessed by the 28-item General Health Questionnaire (GHQ). Respondents were asked about weekly hours of leisure-time exercise for four levels of exercise, and the volume of exercise was assessed using a metabolic equivalent task index. Information about commuting to work on foot or by bicycle was also obtained. The mean GHQ scores were calculated according to physical activity levels using analysis of covariance with adjustment of potential confounders including job stress. In men, the GHQ score decreased steadily with increasing levels of leisure-time exercise, and an inverse association was evident even for mild intensity exercise. Moreover, the GHQ score decreased according to increasing duration of time on commuting to work by either walking or cycling in men, but not in women. These relations did not materially change after adjustment for potential confounding factors. In women, there was no significant association between any of the indices of physical activity. In conclusion, leisure-time exercise and walking or cycling during commuting to work may be associated with better mental health in men. (J Occup Health 2007; 49: 46-52)

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Both depressive symptoms and vitamin D insufficiency are common during winter. This study examined the association between serum 25-hydroxyvitamin D and depressive symptoms by survey season. Subjects were 527 municipal employees aged 21-67 years of two municipal offices in Japan. Overall, there was no measurable association. However, in the workplace surveyed in November, multivariate-adjusted odds ratios (95% confidence interval) of having depressive symptoms (Center for Epidemiologic Studies Depression score of X16) for the lowest through highest quartiles of serum 25-hydroxyvitamin D were 1.00 (reference), 0.84 (0.45-1.58), 0.83 (0.44-1.58) and 0.59 (0.30-1.15), respectively (trend P ¼ 0.14). The association with the severe depressive state was more pronounced. By contrast, there was no such association in the workplace surveyed in July. Overall, this study did not provide evidence linking higher blood vitamin D levels with decreased depressive symptoms. The suggestive inverse association in sun-deprived season warrants further investigation.