Our laboratory recently reported that Toll-like receptor (TLR) 4 may play a role in the neurotoxic effects in mice exposed to the environmental toxic chemical toluene. To investigate the role of TLR4 in hippocampal neurotrophin expression, C3H/HeN (TLR4 intact) and C3H/HeJ (TLR4 defective) male adult mice were administered diazinon (0, 0.05, 0.5 or 5 mg/kg) intraperitoneally once a week for three weeks. Twenty-four hours after the final diazinon injection, the hippocampus was collected from each mouse to detect mRNA expression of neurotrophins (nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF)) by the real-time RT-PCR method. There was no difference between groups in neurotrophin expression in the C3H/HeN mice. However, the expression of NGF and BDNF mRNAs was suppressed significantly in the diazinon-injected C3H/HeJ mice compared with their control group. We also found an increased tendency of proinflammatory chemokine CCL3 mRNA and a marked increase in the proapoptotic gene Bax mRNA in the diazinon-injected C3H/HeJ mice. Our findings indicate that diazinon injection affects neurotrophin expression in the hippocampus in TLR4-defective mice but not in TLR4 intact mice. These results suggest that a defective TLR4 signaling pathway in the mouse hippocampus can be easily affected by diazinon administration.

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In the workplace, localized muscle fatigue can be a limiting factor for prolonged static work. It is important to study the etiology of fatigue in the muscle to prevent discomfort and potential muscle injury. The purpose of this study was to investigate the effect of sustained trunk flexion and loading on the erector spinae muscles (ESM) fatigue using electromyography (EMG) and muscle oxygenation (Mox) changes. Twelve healthy male volunteers, aged between 19 and 28 years (mean age 23 ± 2.6), participated in this study. The subjects held a load (5, 10 and 15 kg) and no load in their hands whilst sustaining trunk flexion at 60° and also in an upright standing posture for 30 seconds. Five minutes rest was given between the conditions, and each condition was randomly repeated three times. Surface EMG and near-infrared spectroscopy were recorded. Root mean square and median frequency (MF) of EMG, and Mox were calculated. The results showed a greater decrease in Mox with an increase in loads over time (P = 0.015). Using unloaded trunk flexion as a control to ascertain load effect resulted in a significant difference in Mox in the unloaded condition and in the 15 kg condition (P = 0.027). EMG results showed a significant decrease in the MF over time in trunk flexion while holding a load (P < 0.001). These results show objectively that trunk flexion while holding loads causes ESM fatigue.

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We review the critical roles of peroxiredoxin (PRDX) 4 in inflammatory diseases. The PRDX family, a new family of proteins with an antioxidative function, is ubiquitously synthesized and abundantly identified in various organisms. The function of these enzymes, which include at least six distinct PRDX genes expressed in mammals, still remains unclear. Especially, in contrast to the intracellular localization of other family members, PRDX4 is the only known secretory form located in the extracellular space and exerts its protective function against oxidative damage by scavenging reactive oxygen species in the vascular vessels. To date, however, it is not clear whether or how PRDX4 expression affects various diseases in vivo. More recently, we generated human PRDX4 (hPRDX4) transgenic (Tg) mice, and, for the first time, established a type 1 diabetes mellitus model induced by a single high dose of streptozotocin on Tg mice. Our published data demonstrate that streptozotocin-treated Tg mice, which overexpress hPRDX4 in pancreatic islets, can protect pancreatic β-cells against streptozotocin-induced injury (insulitis) by suppressing increased oxidative stress and inflammatory signaling activation. These observations indicate that Tg mice could become a useful animal model to study the relevance of oxidative stress to inflammation, and that a specific accelerator of PRDX4 might prove to be a potential therapeutic agent for ameliorating various chronic inflammatory diseases.

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Pulmonary hamartoma is the most common tumor in benign lung neoplasm. We reviewed the clinical characteristics of 9 patients who had undergone surgical resection for pulmonary hamartoma between 2000 and 2009. There were 1 male and 8 female patients. The age of the patients ranged from 42 to 77 years old (mean 59). Calcification was not observed by computed tomography scan except in 1 patient. Although transbronchial lung biopsy (TBLB) was performed in 5 patients, no definitive diagnosis was obtained. Six patients underwent ¹⁸F- fluorodeoxyglucose (FDG) - positron emission tomography, and none of them showed any accumulation of FDG except for 1 patient. Concerning the operative procedures, a sleeve lobectomy was performed in 1 patient, a segmentectomy in 1, a lobectomy in 2, a partial resection of the lung in 3, and a nucleation in 2 patients. The postoperative courses were uneventful, and no findings of recurrence were observed in any of the patients after surgery. As a preoperative diagnosis of pulmonary hamartoma is often difficult in TBLB, it is necessary to perform surgical resection in the differential diagnosis of lung cancer or metastatic lung tumor, unless there are typical findings of pulmonary hamartoma in clinical imaging.

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It is possible that the performance rating of line workers is affected by the risk factors for musculoskeletal disorders that are included in their work more so than by the actual takt time. To investigate whether performance rating relates to the risk factors for musculoskeletal disorders, we analyzed a dataset obtained from a self-administered questionnaire answered by assembly line workers (n=1579). As a result, performance rating had a significant association with unsuitable work environments, poor working postures and handling of heavy loads. The workers who reported the fastest rating had a higher exposure than others to the risk factors for occupational low back pain. The results of our study support the effectiveness of performance rating as an index of work burden.

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Nanoparticles are defined as particles whose diameter is 1-100 nm. Many investigations about the toxicology of nanoparticles have been reported recently. The toxicity of nanoparticles has been examined both in vivo and in vitro and many results are being achieved. However, the results of in vivo and in vitro examinations are sometimes different. According to the in vitro examinations, it is suggested that solubility, adsorption ability and surface activity are involved in the cytotoxicity of nanoparticles. On the other hand, in in vivo, clearance is an important factor in the lung toxicity of nanoparticles. In the hazard assessment of nanoparticles, in vivo and in vitro examinations are necessary for an accurate evaluation of their biological influences, including the toxic mechanisms.

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Fullerene (C₆₀) is a newly generated nanoparticle that has a soccer-ball structure with 60 carbon atoms. Fullerenes are expected to have a multitude of uses, for example as energy device materials or information technology materials. The biological effects of nanoparticles are now being discussed, and there are ongoing animal studies using various nanoparticles. Here we review some reports about the toxicity of C₆₀, and in addition we present the results of our 2-year follow up studies of instillation and inhalation of C₆₀ via the trachea.

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Skin is a large organ which protects our inner body from external stresses. Skin serves not only as a physical barrier but also as an important immune system. Ultraviolet rays B (UVB) activate melanin synthesis by melanocytes in the skin. Melanin, in turn, absorbs UVB and protects the skin from overexposure to UVB. In addition, it is generally known that UVB suppresses immune reaction in the skin. This phenomenon is applied to the treatment of cutaneous diseases such as psoriasis and vitiligo. UVB-induced immunosuppression is mediated by regulatory T cells (Tregs). We and other groups have figured out the mechanism of UVB-induced antigen specific immunosuppression. Here we propose that the role of UVB-mediated immunosuppression is the inhibition of self-destruction against external stresses.

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There are increasing cases of wheat dependent exercise-induced anaphylaxis (WDEIA) with transcutaneous or transmucosal sensitization. Hydrolyzed wheat included in a certain brand of soap was identified as a cause of sensitization. The useful clues to detect this disorder consist of the patient's past usage of a soap containing hydrolyzed wheat, the appearance of cutaneous or mucosal symptoms after the intake of wheat or washing with this soap, and a high level of specific IgE for wheat gluten. Because hydrolyzed wheat is used as an additive in a wide variety of cosmetics, we should pay careful attention to the ingredients of cosmetics when observing WDEIA.

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A questionnaire survey about the public's image of radiation was performed after the Fukushima Daiichi nuclear power plant (FDNPP) accident. The survey was taken by general citizens (200 and 1,640 in Fukushima and 52 outside of Fukushima) and doctors (63 in Fukushima and 1,942 outside of Fukushima (53 in Oita, 44 in Sagamihara and 1,845 in Kitakyushu)) in and outside of Fukushima and second year medical students in the University of Occupational and Environmental Health, Japan. The questionnaire surveys were performed during lectures about radiation. The response rates were 86% for the general citizens in Fukushima, 91% for the general citizens outside of Fukushima, 86% for doctors in Fukushima, and 85% and 86% for doctors in Sagamihara and Oita, respectively. The questionnaire surveys were sent to clinics and hospitals in Fukushima where the general citizens answered with a response rate of 50%. When the questionnaire surveys were sent to clinics and hospitals in Kitakyushu, doctors answered, with a response rate of 17%. The percentages of anxiety about future radiation effects after the FDNPP accident were the highest among the general citizens (71.6% in Fukushima and 40.4% outside of Fukushima), in the middle among the doctors (30.2% in Fukushima and 26.2% outside of Fukushima) and the lowest among the medical students (12.2%). The doctors in Fukushima and the medical students were anxious about food and soil pollution. The general citizens and the doctors outside of Fukushima were anxious about health problems and food and soil pollution. We concluded that a high level of education about radiation decreased the anxiety about the radiation effects. It is important to spread knowledge about radiation.

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