Little is known about the association between depression and the buffering effects of social support in mid-life crisis. The aim of this study is to determine the buffering effects of social support on depression concerning middle-aged individuals, while also taking reciprocity and gender differences into careful consideration. A cross-sectional survey of all middle-aged individuals (40-69 years of age) using a large sample (n = 4558) from a community-living population, who resided in Rokunohe town, Aomori prefecture in northern Japan (response rate = 69.8%), was undertaken. This town recently had a lot of suicides. Two-way anova was used to analyze the effects of stressor and social support on the Center for Epidemiologic Studies Depression scale scores. The authors found a stress buffering effect of social support on the depressive symptoms occurring in middle age, however, a significant difference in the stress buffer effect was only observed in male subjects. Moreover, when the authors take reciprocity into account, the effect of the buffer on depression was found not only in males receiving support but in males providing support as well.In conclusion, pertaining to males, social support reduces depressive symptoms under stressful circumstances in middle age, not only when they receive such support but also when they provide it. Therefore, these findings suggest that reciprocal social support is important for males in relation to community mental health.

Modulations of Immune Functions andOxidative Status Induced by Noise Stress: KuiCheng ZHENG, et al. Department of Environmental and Preventive Medicine, Faculty of Medicine, University of the Ryukyus-Noise has long been realized as an environmental stress causing physiological, psychological and behavioral changes in humans. The aim of the present study was to determine the effect of acute or chronic noise stress on both cellular and humoral immune responses and oxidative status. BALB/c mice were exposed to 90 dB (A) white noise 5 h per day for either 3 d or 4 wk. Hormone levels, splenic lymphocyte proliferation, lymphocyte subsets in spleen and thymus, serum antibody and oxidative status were determined. A 3-d exposure to noise stress resulted in increased hormone levels, splenic lymphoproliferation and serum IgM. On the other hand, a 4-wk exposure to noise stress caused a reduction of splenic lymphoproliferation, splenic CD4 + cells and serum IgG, but hormone levels and urinary 8-hydroxy-2'deoxyguanosine (8-OHdG) were increased. These results imply that acute exposure to noise stress may enhance immune responses, whereas chronic exposure to noise stress may suppress both cellular and humoral immune functions. The effect of noise stress on immune functions may be related to neuroendocrine modulation and oxidative imbalance as well. (J Occup Health 2007; 49: 32-38)

The effects of whole body vibration on the concentrations of noradrenaline (NA), dopamine (DA), and serotonin (5-HT) in the whole brain and brain regions of rats were investigated. Compared with control rats, vibration with 20 Hz frequency decreased the brain concentration of NA only when the acceleration (intensity) was increased to 5.0 G (p less than 0.05). The concentration of DA in the whole brain was not affected by acceleration. When acceleration was kept at a constant 0.4 G level and rats were exposed for the same 240 minute period to 5, 20, or 30 Hz vibration, neither NA nor DA concentrations changed in the whole brain. Regional changes in the concentration of biogenic amines in the brain of rats exposed to vibration of 20 Hz and 5.0 G showed few significant differences. Thus NA significantly decreased only in the hypothalamus (p less than 0.01), although in the hippocampus the decrease was nearly significant (p less than 0.10). The concentration of 5-HT significantly increased in the hypothalamus and cerebellum (p less than 0.05). DA tended to increase in the cortex and decrease in the striatum (p less than 0.10). These experiments seem to indicate that NA in the whole brain and especially in the hypothalamus is a better indicator of vibration exposure than 5-HT, and that NA is affected by the intensity but not by the frequency of vibration. NA and 5-HT in the hypothalamus change in the opposite direction. DA concentrations in the brain are basically unaffected by vibration.

No abstract

The purpose of this study was to understand the peculiarity of the development of HandArm Vibration Syndrome (HAVS) in a subtropical area of Japan. We analyzed the medical records of 21 subjects reported by the Okinawa Labor Bureau, and tried to determine whether the warm environment has any effect on the severity of HAVS. The mean operating time of vibration tools for all the subjects was over 10,000 hrs. Almost all the subjects from Okinawa had been working only in Okinawa. The presence of Vibration Induced White Fingers (VWF) was markedly smaller in the subjects from Okinawa as compared to those from other prefectures. The results of Cold Water Immersion Tests were similar for all subjects. Ten minutes after the Cold Water Immersion Test, the mean finger skin temperature was about 19°C in all subjects. These findings suggest that not only the operating time of vibration tools but also the warm environment might have an effect on the severity of HAVS. However, the number of subjects in our study was very small. There is the need therefore for further investigations with a larger number of subjects.