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Takeuchi A.,Osaka Occupational Health Service Center | Sakano N.,Kagawa University | Miyatake N.,Kagawa University
Industrial Health | Year: 2014

This study describes an ecological study that evaluated the combined effects of working hours, income, and leisure time on suicide in all 47 prefectures of Japan. In men, the age-adjusted rate of suicide (per 100,000 population) was significantly correlated with working hours (r=0.587, p<0.0001) as well as significantly and negatively correlated with income (r=-0.517, p=0.0002) and times for the leisure activities of self-education (r=-0.447, p=0.0016) and hobbies (r=-0.511, p=0.0002). In addition, a stepwise multiple regression analysis identified time for leisure social activities as a determining factor in suicide rate, even after adjusting for working hours and income. However, the impact of time for leisure social activities on suicide rate was smaller than that of working hours and income. In contrast, none of these factors affected suicide rate in women. These results suggest that increasing leisure time may be useful for preventing suicide among men in Japan. © 2014 National Institute of Occupational Safety and Health.


Ogino K.,Okayama University of Science | Takahashi N.,Okayama University of Science | Kubo M.,Okayama University of Science | Takeuchi A.,Osaka Occupational Health Service Center | And 2 more authors.
Environmental Toxicology | Year: 2014

To evaluate the allergic effect of airborne particulate matter (PM) on the airway, separated soluble supernatant (Sup) and insoluble precipitate (Pre) in suspended PM were inoculated into NC/Nga mice with a high sensitivity for mite allergens. Sup, Pre, or both Sup and Pre with or without pronase treatment were inoculated via the nasal route five times for sensitization and a challenge inoculation on the 11th day in NC/Nga mice. On the 14th day, mice were examined for airway hyperresponsiveness (AHR), bronchoalveolar lavage fluid (BALF) cell count, mRNA expression of Th1 and Th2 cytokines in the lung tissue, and histopathology. Synergistic effects of Sup and Pre were observed as increases in AHR and a histopathological change of Periodic acid-Schiff (PAS) staining. Increases in neutrophils, macrophages, and lymphocytes of BALF cells were dependent on Pre. The expression of IL-4 mRNA was increased by Sup, and those of IL-5 mRNA and Il-13 mRNA was increased by Sup and Pre. Augmented AHR, mRNA expression of IL-4, peribronchial inflammation, and PAS staining by Sup plus Pre were attenuated by treatment of Sup with pronase to digest proteins. These results suggest that some proteins of ambient PM may be important environmental factors for AHR and airway inflammation with the aid of insoluble particulates, although some soluble factors such as endotoxins cannot be ruled out. © 2012 Wiley Periodicals, Inc.


Araki A.,Hokkaido University | Kanazawa A.,Hokkaido University | Kawai T.,Osaka Occupational Health Service Center | Eitaki Y.,Osaka Occupational Health Service Center | And 9 more authors.
Science of the Total Environment | Year: 2012

Microbial volatile organic compounds (MVOCs) are a type of VOCs produced by microorganisms. Exposure to 1-octen-3-ol, one of the known MVOCs, has been reported to reduce nasal patency and increase nasal lavage myeloperoxidase, eosinophil cationic proteins, and lysozymes in both experimental and field studies. We reported in a previous paper that 1-octen-3-ol exposure at home is associated with mucosal symptoms. In this study, our aim was to investigate the relationship between asthma and allergies and MVOC exposure in single-family homes. The subjects were 624 inhabitants of 182 detached houses in six regions of Japan. Air samples were collected using diffusive samplers, and the concentrations of eight selected MVOCs were analyzed using gas chromatography/mass spectrometry in selected-ion-monitoring mode. Each inhabitant of each of the dwellings was given a self-administered questionnaire. Among the 609 subjects who answered all of the questions about allergies, history of the medical treatment for asthma, atopic dermatitis, allergic rhinitis, and allergic conjunctivitis within the preceding two years was 4.8%, 9.9%, 18.2%, and 7.1%, respectively. A significant association between 1-octen-3-ol (per log10 unit) and allergic rhinitis odds ratio (OR): 4.10, 95% confidence interval (CI): 1.71 to 9.80 and conjunctivitis (OR: 3.54, CI: 1.17 to 10.7) was found after adjusting for age, sex, tobacco, wall-to-wall carpeting, signs of dampness, history of treatment for hay fever, and other potentially relevant environmental factors. No relationships were found between any MVOCs and asthma or atopic dermatitis after the adjustment. The levels of MVOCs and airborne fungi were only weakly correlated. These results are consistent with previous studies that have associated higher levels of 1-octen-3-ol exposure with increased irritation of nasal and ocular mucosae. Although the indoor-air concentrations of 1-octen-3-ol found in this study were relatively low, we conclude that exposure to MVOC may be related to rhinitis and conjunctivitis. © 2012 Elsevier B.V.


Namera A.,Hiroshima University | Takeuchi A.,Osaka Occupational Health Service Center | Saito T.,Tokai University | Miyazaki S.,GL Sciences Inc. | And 3 more authors.
Journal of Separation Science | Year: 2012

A sequential analytical method was developed for the detection of arsenite, arsenate, and methylarsenate in human urine by gas chromatography-mass spectrometry (GC-MS). The combination of a derivatization of trivalent arsenic compounds by 2,3-dithio-1-propanol (British antilewisite; BAL) and a reduction of pentavalent arsenic compounds (arsenate and methylarsenate) were accomplished to carry out the analysis of arsenic compounds in urine. The arsenic derivatives obtained using BAL were extracted in a stepwise manner using a monolithic spin column and analyzed by GC-MS. A linear curve was observed for concentrations of arsenic compounds of 2.0 to 200 ng/mL, where the correlation coefficients of calibration curves were greater than 0.996 (for a signal-to-noise (S/N) ratio >10). The detection limits were 1 ng/mL (S/N > 3). Recoveries of the targets in urine were in the range 91.9-106.5%, and RSDs of the intra- and interday assay for urine samples containing 5, 50, and 150 ng/mL of arsenic compounds varied between 2.95 and 13.4%. The results from real samples obtained from a patient suspected of having ingested As containing medications using this proposed method were in good agreement with those obtained using high-performance liquid chromatography with inductively coupled plasma mass spectrometry. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


PubMed | Hokkaido University, Osaka Occupational Health service Center and Hokkaido University of Science
Type: Comparative Study | Journal: International journal of hygiene and environmental health | Year: 2015

We measured urinary phthalate metabolites, including di-n-butyl phthalate (DnBP), di-isobutyl phthalate, benzyl butyl phthalate (BBzP), and di(2-ethylhexyl) phthalate (DEHP), from 178 school-aged children and their 284 family members using gas chromatography-mass spectrometry, and we calculated daily phthalate intakes. The highest median levels of phthalate metabolites were for mono-isobutyl phthalate in all participants except schoolchildren, where the highest levels were for mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP). Comparing the schoolchildren with their parents, the schoolchildren had significantly higher urinary metabolites for MEOHP, mono-(2-ethyl-5-carboxypentyl) phthalate, and DEHP. Regarding daily intakes, the schoolchildren had significantly higher daily intakes of DnBP, BBzP, and DEHP. All phthalate metabolite and sums of metabolite levels in the schoolchildren were positively correlated with their mothers levels, except for MEHP, whereas fathers were less correlated with their children. The DEHP intake in this study was higher than that of most other studies. Moreover, 10% of the children and 3% of the adults exceeded the Reference Dose (RfD) value (20g/kg/day) of the U.S. Environmental Protection Agency, which indicates that it is important to focus on childrens DEHP exposure because the children exceeded the RfD more than adults among the same families who shared similar exposure sources. Our results will contribute to considerations of the regulations for some phthalates and the actual phthalate exposure levels in the Japanese population.


Kawai T.,Osaka Occupational Health Service Center | Mitsuyoshi K.,Osaka Occupational Health Service Center | Ikeda M.,Kyoto Industrial Health Association
Journal of Occupational Health | Year: 2015

Objectives: The aim of this study was to examine the applicability of urinalysis for unmetabolized solvent to biomonitor 1,2-dichloropropane (1,2-DCP) exposure. Methods: Thirty three male printers exposed to 1,2-DCP and 5 nonexposed male controls participated in the study. The 8-hr average levels of exposure to 1,2-DCP in air and 1,2-DCP in the end-of-shift urine samples were measured with capillary FID-GC. Results: The geometric mean (the maximum) concentrations was 7.1 ppm (23.1 ppm) for 1,2-DCP in air, and the level in urine (without correction for urine density) was 77 μ g/l (247 μ g/l). A regression analysis showed a correlation coefficient of 0.909 (p<0.01). No 1,2-DCP was detected in the urine samples from nonexposed subjects. Conclusions: The high correlation and low background (essentially zero) showed that urinalysis for unmetabolized 1,2-DCP is a promising tool for biomonitoring of occupational exposure to this carcinogenic solvent at lower levels (e.g. <1 ppm). © 2015. Japan Society for Occupational Health.


Kawai T.,Osaka Occupational Health Service Center | Takeuchi A.,Osaka Occupational Health Service Center | Ikeda M.,Kyoto Industrial Health Association
Journal of Occupational Health | Year: 2015

Comparison of the exposure-excretion relationship between men and women exposed to organic solvents: Toshio KAWAI, et al. Osaka Occupational Health Service Center-Objectives: The present study was initiated to examine if application of the same biological occupational exposure limits (BOELs) for organic solvents is applicable across the sexes. Methods: A survey was conducted in 69 micro-scale enterprises in a furniture-producing industrial park. In practice, 211 men and 52 women participated in the survey. They worked in a series of production process, and were exposed to solvent vapor mixtures. The exposure intensities were monitored with two types of diffusive samplers, one with carbon cloth (for solvents in general) and the other with water (for methyl alcohol) as adsorbents. Solvents in the adsorbents and head-space air from urine samples were analyzed with capillary FID-GC. The measured values were subjected to linear regression analysis followed by statistical evaluation for possible sex-related differences in slopes. Results: Essentially no significant difference was detected between men and women in regression line parameters including slopes. Possible differences in the cases of acetone and toluene were discussed and excluded. Conclusions: With the exceptions for acetone and toluene, the present study did not detect any clear differences between men and women. In examinations of past reports, no support for the observed differences was found. The present findings deserve further study so that a solid conclusion can be formed.


Eitaki Y.,Keio University | Kawai T.,Osaka Occupational Health Service Center | Omae K.,Keio University
Journal of Occupational Health | Year: 2011

Objectives: In order to measure occupational exposure concentrations of ethyl tertiarybutyl ether (ETBE), we developed a diffusive sampling method for monitoring ETBE and performed an ETBE exposure assessment. Methods: The applicability of diffusive samplers was examined by exposing the samplers to ETBE vapor in test chambers. The personal exposure levels of workers and airborne concentrations were measured at 4 gas stations. Results: The ETBE sampling rate for the diffusive samplers (VOC-SD, Sigma-Aldrich Japan) was 25.04 ml/min (25°C). Compared with the active sampling method, the diffusive samplers could be used for short-term measurements and in environments containing a mixture of organic solvents. The geometric mean (GM) of TWA-8h ETBE was 0.08 ppm (0.02-0.28 ppm) in 28 gas station workers and 0.04 ppm (0.01-0.21 ppm) in 2 gasoline tanker truck drivers. With regard to ETBE airborne concentrations, the GM was 4.12 ppm (0.93-8.71 ppm) at the handles of hanging pumps but dropped to less than 0.01 ppm (less than 0.01-0.01 ppm) at the side of a public road. Conclusion: The diffusive sampling method can be used for the measurement of occupational ETBE exposure. The threshold limit of TLV-TWA 5 ppm recommended by the ACGIH was not exceeded in any of the workers in this study.


Tajima S.,Hokkaido University | Araki A.,Hokkaido University | Kawai T.,Osaka Occupational Health Service Center | Tsuboi T.,Osaka Occupational Health Service Center | And 6 more authors.
Science of the Total Environment | Year: 2014

The demand for phosphorus flame retardants (PFRs) has recently increased as an alternative to polybrominated diphenyl ether (PBDE). PFRs have been detected in house dust, but little is known about the concentrations of PFRs in private homes and the effects on human health. We measured the levels of 10 PFRs in indoor floor dust and upper surface dust from 128 Japanese dwellings of families with children in elementary school. The median (min-max) concentrations (μg/g) of PFRs were as follows: tris(2-butoxyethyl) phosphate (TBOEP), 30.88 (<. 0.61-936.65); tris(2-chloro-. iso-propyl) phosphate (TCIPP), 0.74 (<. 0.56-392.52); and triphenyl phosphate (TPHP), 0.87 (<. 0.80-23.35). These values exceeded 50% detection rates, and the rates are median over the LOD in floor dust. The concentrations (μg/g) of TBOEP 26.55 (<. 0.61-1933.24), TCIPP 2.23 (<. 0.56-621.23), TPHP 3.13 (<. 0.80-27.47), tris(2-chloroethyl) phosphate (TCEP) 1.17 (<. 0.65-92.22), and tributyl phosphate (TNBP) 0.74 (<. 0.36-60.64) exceeded 50% detection rates in the upper surface dust. A significant positive correlation (P. <. 0.05) between the concentrations of TCIPP and TBOEP was shown in floor dust and upper surface dust (n. = 48). Estimated median and 95th percentile daily intake was calculated for toddlers and elementary school children and was compared with reference dose values (RfD) from the literature. For TBOEP, the estimated 95th percentile intake from floor dust was 14% of RfD for toddlers and 4% for school children. The estimated intake from upper surface dust was somewhat lower. Estimated median intake of TBOEP and median intake for the other PFRs were less than 1% of the RfD. TBOEP, TCIPP and TPHP were the main PFRs in the dust. The median levels of PFRs are well below the RfD values. © 2014 Elsevier B.V.


PubMed | Osaka Occupational Health Service Center
Type: Journal Article | Journal: Journal of occupational health | Year: 2015

The aim of this study was to examine the applicability of urinalysis for unmetabolized solvent to biomonitor 1,2-dichloropropane (1,2-DCP) exposure.Thirty three male printers exposed to 1,2-DCP and 5 nonexposed male controls participated in the study. The 8-hr average levels of exposure to 1,2-DCP in air and 1,2-DCP in the end-of-shift urine samples were measured with capillary FID-GC.The geometric mean (the maximum) concentrations was 7.1 ppm (23.1 ppm) for 1,2-DCP in air, and the level in urine (without correction for urine density) was 77 g/l (247 g/l). A regression analysis showed a correlation coefficient of 0.909 (p<0.01). No 1,2-DCP was detected in the urine samples from nonexposed subjects.The high correlation and low background (essentially zero) showed that urinalysis for unmetabolized 1,2-DCP is a promising tool for biomonitoring of occupational exposure to this carcinogenic solvent at lower levels (e.g. <1 ppm).

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