Modulations of immune functions and oxidative status induced by noise stress.

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.

Stress buffering effects of social support on depressive symptoms in middle age: reciprocity and community mental health.

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.

Potassium excretion in healthy Japanese women was increased by a dietary intervention utilizing home-parcel delivery of Okinawan vegetables.

Potassium, which is abundant in vegetables, is inversely related to blood pressure. Although the situation has changed somewhat in recent years, the Okinawan diet has generally included a large amount of vegetables, and until recently Okinawans had the lowest rates of mortality due to stroke and coronary heart disease in Japan. Based on the hypothesis that these low mortality rates are partly attributable to increased potassium intake resulting from the high vegetable consumption, this study examined whether increasing the consumption of typical yellow-green Okinawan vegetables increases potassium intake. The purpose of this investigation was to determine whether increased consumption of these vegetables should be one of the dietary modifications recommended in public health promotion programs for Okinawans. The study employed 56 healthy, normotensive, free-living Japanese women aged 18-38 years living in Okinawa. They were randomized to a dietary intervention group (n=27) or a control group (n=29). Members of the dietary intervention group received an average weight of 371.4 g/day of a combination of the following vegetables twice weekly through an express home parcel deliver service for a period of 14 days: Goya (Momordica charantia), green papaya (Carica papaya), Handama (Gynura bicolor), Karashina (Brassica juncea), Njana (Crepidiastrum lanceolatium), Fuchiba (Artemisia vulgaris) and Fudanso (Beta vulgaris); and they consumed an average of 144.9 g/day, resulting in a 20.5% increase in their urinary potassium excretion over the baseline (p=0.045). The members of the control group were asked to avoid these vegetables, and the change in potassium excretion in this group was not significant (p=0.595). Urinary sodium and magnesium excretions, systolic and diastolic blood pressures, folic acid, triglycerides and serum high density lipoprotein cholesterol, low density lipoprotein cholesterol and total cholesterols changed non-significantly in both groups. Also, post-intervention urinary potassium excretion correlated positively with vegetable consumption in both the dietary intervention (p<0.0001) and control (p=0.008) groups and with Okinawan vegetable intake in the dietary intervention group (p=0.0004).

Associations between lifestyle and mental health in a group of Japanese overseas workers and their spouses resident in Düsseldorf, Germany.

This study investigated associations between lifestyle factors and selected aspects of mental health in a group of Japanese overseas workers and their accompanying spouses who were residing in and around Düsseldorf, Germany, in February 1994. Considering four aspects of mental health (depression, mental instability, nervousness and neurosis) and six lifestyle factors (alcohol consumption, sleeping hours, cigarette smoking, physical exercise, eating breakfast and eating snacks), a cross-sectional study involving 822 volunteers (486 workers and 336 spouses) was performed using the Todai Health Index (THI) for surveying self-perceived health and a lifestyle related self-administered questionnaire. Alcohol consumption had no associations with any of the four aspects of mental health, and only very weak inverse associations were found between the other five lifestyle factors and the four aspects of mental health in the workers group. In the spouses group, physical exercise was the only lifestyle factor significantly associated with mental health.

Airway inflammatory and immunological events in a rat model exposed to toluene diisocyanate.

To investigate the inflammatory and immunological events in the airway induced by a short period of repeated exposure to toluene diisocyanate (TDI), an animal model was established, which resembled the industrial field exposure. After whole body exposure of Wistar rats to 0.38 and 1.20 ppm TDI vapor 4h a day for five consecutive days in a glass chamber, bronchoalveolar lavage (BAL) was performed. BAL fluid cellular and cytokine contents were then determined. Histopathological examinations were also carried out on the lungs. The TDI vapor exposure resulted in airway symptoms similar to those in occupational asthma. BAL fluid cellular analysis and lung histopathological examination revealed that inflammatory response was characterized by marked eosinophil infiltration of the airways. The cytokine assay revealed significant production of IL-4 in the airways of the TDI exposed rats as compared to the control rats. These findings indicated that a short period of repeated exposure to TDI vapor may cause respiratory hypersensitivity in which airway inflammatory and immunological events represented by eosinophil infiltration and Th2 cytokines may play an important role. Also, this animal model may be suitable for exploring the mechanism underlying TDI-induced occupational asthma.

Influence of heat exposure on serum lipid and lipoprotein cholesterol in young male subjects.

The aims of the present study were to determine the effects of passive heat exposure on serum lipid concentrations in healthy young Japanese males and to analyze the relationship between subjects' physical characteristics and the extent of change in serum lipid concentrations. Thirteen subjects with mean ages of 22.6 +/- 1.0 (mean +/- SE) years were each exposed to control temperature (Tc: 25.2 +/- 0.0 degrees C), moderate (Tm: 35.5 +/- 0.2 degrees C) and high temperature(Th: 39.8 +/- 0.1 degrees C), at a relative humidity of 60.3 +/- 1.2% for one hour. Each exposure was carried out on a different day in random sequence. Blood samples were collected just before, during and after the exposure, and serum lipid concentrations were analyzed. In the Tc condition, the concentrations of total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), triglyceride (TG), and free fatty acid (FFA) did not change significantly. In the Tm condition, HDL-C increased significantly after the exposure and FFA increased during and after exposure. While in the Th condition, TC and TG decreased significantly during and after exposure, and LDL-C decreased during exposure. The correlation between changes in serum lipid concentrations and physical characteristics was analyzed if lipid concentrations changed significantly during or after exposure, but no significant correlation was found. The results indicate passive heat exposure has an effect on serum lipid concentrations which is independent of physical characteristics.

A study of the hand-arm vibration syndrome in Okinawa, a subtropical area of Japan.

The purpose of this study was to understand the peculiarity of the development of Hand-Arm 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 degrees 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.