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This study examined the effectiveness of a field-type liquid cooling vest (LCV) worn underneath an impermeable protective suit on heat strain during walking. Eight men walked for 60 min at a moderate speed (3.0 km/h) wearing the suit in a warm environment (33°C, 60% relative humidity) without (control, CON) or with the LCV. A smaller increase in rectal temperature was recorded in participants in the LCV than in the CON condition (37.6 ± 0.1°C vs. 37.9 ± 0.1°C, p

Smell of very low dose of chemical might evoke subjective physical symptoms in human by some process of learning named the aversion conditioning. But few scientific evidences of the hypothesis have been reported so far. Validity of conditioned odor aversion (COA) using low-doses of organic solvent as odor conditioned stimulus (CS) was examined. In conditioning phase, water-deprived male Sprague-Dawley rats were presented low, medium or high dose solution for 30 min followed by 0.3 M Lithium Chloride (LiCl) solution or saline injection. The xylene solution and drink water were simultaneously provided on the next day as two-bottle test. Consumption of medium dose of xylene solution was significantly decreased in LiCl injection group as compared with saline group. There was no difference between LiCl and saline injected animals in low group. Animals in high dose did not access to xylene even on the conditioning. These results indicate that animals showed high sensitivity for discrimination against concentration of xylene and that the medium dose of xylene functioned as the CS. We concluded that the COA used in the present study may be one of useful procedures to investigate olfaction of animal.

Objectives It is considered that sleep restriction is one of the risk factors for the development of exertional heat stroke and illness. However, how sleep restriction affects exertional heat strain and the nature of the coping strategy involved in this phenomenon remain unclear. Methods Fourteen healthy subjects were studied on four occasions: after a night of normal sleep (NS, 7–8 h) and after a night of partial sleep restriction (PSR, 4 h), each with or without taking a daytime nap during the subsequent experimental day. The laboratory test consisted of two 40 min periods of moderate walking in a hot room in the morning and the afternoon. Results The increase in rectal temperature during walking was significantly greater in PSR than in NS in the afternoon. The rating scores for physical and psychological fatigue and sleepiness were significantly greater in PSR than in NS, both in the morning and in the afternoon. The reaction times and lapses in the psychomotor vigilance task (PVT) after walking were significantly worse in PSR than in NS in the morning and after lunch. The nap intervention attenuated significantly the scores for fatigue and sleepiness in PSR. Furthermore, the decreased PVT response in PSR was significantly reversed by the nap. Conclusions These results suggest that PSR augments physiological and psychological strain and reduces vigilance in the heat. Taking a nap seemed to be effective in reducing psychological strain and inhibiting the decrease in vigilance.

This study compared heat strain during walking while wearing impermeable protective suits between fan-precooling and nonprecooling conditions. Six males engaged in 60 min of walking at a moderate speed (∼2.5 km/h) in a hot environment (37 °C, 40 % relative humidity). Fanning using a fan (4.5 m/s) and spraying water over the body before wearing the suits produced significantly lower rectal temperature before the walking (37.3 ± 0.1 °C vs. 37.0 ± 0.1 °C, P

The thymus of IQI/Jic mice aged 3 to 15 months was studied chronologically by flow cytometry and immunohistochemistry. Thymic B cells (Thy B) expressing the surface marker B220+IgM+ were detected in both sexes, but were more prominent in females. Thy B appeared as early as 4 months of age in female mice, and the incidence of Thy B-positive mice and average Thy B ratio in thymocytes increased with age, reaching over 90% and 15%, respectively, after 9 months of age. In males, Thy B-positive animals appeared around 9 months of age and its incidence and average ratio increased gradually to 53% and 5%, respectively, at 15 months. The Thy B-rich thymus was thickened with cortical atrophy and medullary hyperplasia. Small- to medium-sized Thy B crowded and often formed follicle-like structures in the medulla. When mice of various ages were injected with mercuric chloride to induce antinucleolar antibody, many Thy B-rich animals could not develop the antibody, implying that these animals are immunologically impaired. IQI/Jic can be a novel strain to elucidate the relationship between the presence of Thy B and disorders of the immune system.

Numerous plasma cells and B cells were present in the thymuses of aged WHT/Ht mice. Plasma cells containing IgG and the follicle-like structure were present in the cortex and medulla, respectively. In these respects, WHT/Ht strain of mice is unique and interesting for studies on lymphocyte development.

Pre-cooling (i.e., removal of heat from the body immediately prior to exercise) is a popular strategy for improving exercise performance in hot conditions. Whole body immersion in water is the procedure most commonly used to pre-cool in sports activities. However, the supply of a large volume of water and ice in all occupational settings is not always possible, or practical. In the present study, we examined the effectiveness of hands and feet water immersion and cooling vest as practical pre-cooling method on heat strain while wearing protective clothing.

The effect of lipopolysaccharide (LPS) on humoral and cell-mediated immunity was assessed using LPS-sensitive C3H/HeN mice. A single injection of LPS significantly decreased the anti-sheep red blood cells (SRBC) antibody titers, but not the number of anti-SRBC antibody producing spleen cells. In contrast, double LPS injection did not significantly decrease the anti-SRBC titers and even increased the number of anti-SRBC antibody producing spleen cells. Similarly, single LPS injection significantly suppressed the swelling of the footpad, but double LPS injection caused milder suppression. These results suggest that a difference in the level and timing of exposure to LPS may influence the immune response to infection or vaccination.

In a study of 142 Japanese men from a cross-section of the workforce of a technology development company, we found that the percentage of CD56+ cells was inversely correlated with the number of hours worked per week. A low CD56+ cell percentage was associated with longer weekly working hours and shorter daily sleeping hours.

The effect of 50 Hz electromagnetic fields on the immune system was assessed by measuring the cytokine production of the peripheral blood mononuclear cells (h-PBMCs) of a healthy individual. The h-PBMCs were exposed in vitro to varying magnetic flux densities of 1, 3, 10, and 30 milli Tesla for 3 days. Changes in cytokine production of IL-1 beta, IL-2, IL-6, IL-10, IFN-gamma, and TNF-alpha were studied using the ELISA method. Significant reduction in TNF-alpha production by the EMF-exposed h-PBMCs, in comparison with the non-exposed cells, was detected at all exposure levels (p < 0.05, p < 0.01). Significant increase in IL-1 beta production and decrease in IFN-gamma production were also detected at some exposure strength. No significant differences were detected between the control and the EMF-exposed cells in the production of the other cytokines.

In the liver of mice surviving for 2 weeks or more after intravenous inoculation of Tyzzer's organisms, MSK strain, were observed giant cell granulomas with intracellular deposition of mucopolysaccharide and calcium, while bacterial antigen was not detectable. Serum antibody was positive in all cases already at 2 weeks postinoculation and high-titered antibody remained at 9 weeks of infection.

Japan is experiencing high temperatures and relative humidity (rh) during the summer months, which lead to increases in the incidence of heat stroke among outdoor workers. According to the Ministry of Health, Labour and Welfare in Japan, between 2010 and 2012, approximately 86 deaths were caused by heat stroke, of which 40% occurred at construction sites [1]. This study aimed to determine whether physical performance, especially balance ability, deteriorates with increased physical workload and heat exposure. In addition, we aimed to determine the relationship of physiological responses and balance function with heat exposure.