Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
Volume 49, Issue 3
Displaying 1-10 of 10 articles from this issue
Original
  • Md H. Mahbub, Kenjiro Yokoyama, Md S. Laskar, Masaiwa Inoue, Yukio Tak ...
    2007 Volume 49 Issue 3 Pages 165-171
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    This study was designed to assess the influence of an antivibration glove on digital vascular responses in healthy subjects exposed to short-term grasping of a vibrating handle. To measure finger blood flow (FBF) and finger skin temperature (FST) once at the end of every min, a blood flowmeter sensor was attached to the dorsum and a thermistor sensor was attached to the medial surface of the subject's middle phalanx of the third finger of the right hand. After 5 min of baseline measurements without or with an antivibration glove meeting ISO standard 10819, worn on the right hand, subjects gripped a vibrating handle with the same hand for a period of 5 min. Vibration was generated at two frequencies of 31.5 Hz and 250 Hz with a frequency weighted rms acceleration of 5.5 m/s2. FBF and FST continued to be recorded for a further 5 min after release of the vibrating handle. Statistical analysis showed no significant change after vibration exposure in either FST or FBF at 250 Hz, compared to baseline (control) measurements while using the antivibration glove. At 31.5 Hz, FBF data exhibited a significant difference between before and after grasping of vibrating handle, which was less under the condition of wearing the antivibration glove than under the condition of bare hand. The results provide evidence that the antivibration glove considerably influenced finger vascular changes in healthy subjects induced by vibration exposure, especially against high frequency vibration. Further studies are required to assess finger vascular responses to hand-transmitted vibration with antivibration gloves of different manufacturers.
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  • Yuki Ito, Osamu Yamanoshita, Nobuyuki Asaeda, Yoshiaki Tagawa, Chul-Ho ...
    2007 Volume 49 Issue 3 Pages 172-182
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    Di(2-ethylhexyl)phthalate (DEHP), a commonly used industrial plasticizer, causes liver tumorigenesis presumably via activation of peroxisome proliferator-activated receptor alpha (PPARα). The mechanism of DEHP tumorigenesis has not been fully elucidated, and to clarify whether DEHP tumorigenesis is induced via PPARα, we compared DEHP-induced tumorigenesis in wild-type and Pparα-null mice. Mice of each genotype were divided into three groups, and treated for 22 months with diets containing 0, 0.01 or 0.05% DEHP. Surprisingly, the incidence of liver tumors was higher in Pparα-null mice exposed to 0.05% DEHP (25.8%) than in similarly exposed wild-type mice (10.0%). These results suggest the existence of pathways for DEHP-induced hepatic tumorigenesis that are independent of PPARα. The levels of 8-OHdG increased dose-dependently in mice of both genotypes, but the degree of increase was higher in Pparα-null than in wild-type mice. NFκB levels also significantly increased in a dose-dependent manner in Pparα-null mice. The protooncogene c-jun-mRNA was induced, and c-fos-mRNA tended to be induced only in Pparα-null mice fed a 0.05% DEHP-containing diet. These results suggest that increases in oxidative stress induced by DEHP exposure may lead to the induction of inflammation and/or the expression of protooncogenes, resulting in a high incidence of tumorigenesis in Pparα-null mice.
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  • Toshihiro Kawamoto, Mihi Yang, Yong-Dae Kim, Heon Kim, Tsunehiro Oyama ...
    2007 Volume 49 Issue 3 Pages 183-189
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    This study aimed to clarify the variation of urinary excretion of 1-hydroxypyrene, which is a major metabolite of pyrene, in relation to lifestyle, including factors such as diet and smoking. The study subjects were 251 workers (male: 196, female: 55, mean age: 44.3) who were not occupationally exposed to PAHs. Urine specimens were collected from 8:00 a.m. to 11:00 a.m. and their 1-hydroxypyrene concentrations were determined by HPLC. A questionnaire was distributed in order to learn gross aspects of the subjects' lifestyles, i.e., smoking, alcohol consumption, coffee/black tea intake, and dietary habits. Multiple linear regression analysis revealed that cigarette consumption most strongly affected the 1-hydroxypyrene level in urine, followed by dietary balance. The urinary 1-hydroxypyrene concentrations of smokers were about 2 times higher than those of non-smokers. Subjects who ate more meat and/or fish excreted 1.5-2 times more 1-hydroxypyrene in urine than those who ate more vegetables.
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  • Kyoko Nishiuchi, Akizumi Tsutsumi, Soshi Takao, Sachiko Mineyama, Nori ...
    2007 Volume 49 Issue 3 Pages 190-198
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    Supervisors at work play a large role in stress management at the workplace. Providing supervisors with necessary information and useful skills might be one effective approach that will lead to stress reduction. However, very few studies have investigated the effect of supervisor education by using a rigorous study design. In a randomized controlled trial, we tried to clarify how an education program for stress reduction influences supervisor knowledge, attitudes, and behavior concerning stress management. The subjects were 46 supervisors of an old, established sake brewery manufacturer of 301 employees. The supervisors were assigned to either the intervention group (24 supervisors) or the control group (22 supervisors). We conducted a single-session education program that included the guidelines for worker mental health promotion to the intervention group. The education program was composed of a basic education lecture and active listening training. The effects of this program on supervisor knowledge, attitudes, and behavior were measured using an original, self-administered questionnaire. The intervention effect was tested by examining an interaction effect between groups and time (before education, three and six months after education). The education favorably affected supervisor knowledge (F=7.92; p=.001). As for behavior, the intervention effect was marginally statistically significant (F=2.51; p=.088). For the attitude score, however, there were no beneficial effects. In conclusion, the provision of necessary information and useful skills to supervisors seems to improve supervisor knowledge and behavior regarding stress management at the workplace for at least six months.
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  • Shinji Yamamoto, Mieko Iwamoto, Masaiwa Inoue, Noriaki Harada
    2007 Volume 49 Issue 3 Pages 199-204
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    The aim of this study was to investigate the usefulness of heart rate variability (HRV) and urinary catecholamines (CA) as objective indices of heat stress effect. We examined physiological responses, subjective symptoms, HRV and urinary CA to evaluate the effect of heat exposure on the autonomic nervous system. Six healthy male students volunteered for this study. They were exposed on different days to either a thermoneutral condition at wet bulb globe temperature (WBGT) 21°C, or a heated condition at WBGT 35°C for 30 min, while seated on a chair. In the thermoneutral condition, differences of all parameters between the values before and after 30 min exposure were not statistically significant. In the heated condition, heart rate, body temperature and scores for subjective symptoms (feverishness, sweating, mood, and face flushing) significantly increased after 30 min exposure (p<0.05). Also, the high frequency component (HF%) of HRV significantly decreased and the low frequency/high frequency (LF/HF) ratio of HRV significantly increased after 30 min exposure to the heated condition (p<0.05). There were no significant differences between the amounts of urinary CA before and after the 30 min exposures; however, the norepinephrine amount after 30 min exposure to the heated condition was significantly greater than that of the thermoneutral condition (p<0.05). The heat exposure (WBGT 35°C) induced activation of the sympathetic nervous system and a withdrawal of the parasympathetic nervous system. These findings coincide with observed changes of heart rate, body temperature and subjective symptoms. It is suggested that HRV (HF% and LF/HF ratio) and urinary norepinephrine may be useful objective indices of heat stress; HRV seems to be more sensitive to heat stress than urinary CA.
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  • Akiko Nogi, Jianjun Yang, Limei Li, Masayuki Yamasaki, Minako Watanabe ...
    2007 Volume 49 Issue 3 Pages 205-216
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    The favorable role of n-3 polyunsaturated fatty acid (PUFA) in cardiovascular disease (CVD) has been demonstrated in animal experiments and in humans in Western countries, but its effect remains controversial in Asian populations. An observational study of Japanese, Koreans and Mongolians with extended histories of remarkably different frequencies of fish intake was conducted to examine whether differences in plasma n-3 PUFA affects CVD risk factors. We conducted a cross-sectional study in workplace settings and determined body mass index (BMI), blood pressure, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride (TG), glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and fatty acid composition in plasma. A total of 411 Japanese, 418 Korean and 252 Mongolian workers aged 30-60 yr participated in this study. The Japanese ate fish more frequently and had remarkably higher values of eicosapentaenoic acid, docosahexaenoic acid and n-3 PUFA, and lower values of BMI and HOMA-IR, followed by the Koreans, and then the Mongolians. In age groups, the Japanese and Koreans showed a similar tendency of increase in n-3 PUFA with increasing age. General linear measurement multivariate analysis after adjustment for gender, age, smoking, drinking, exercise habits and BMI showed n-3 PUFA was associated with HDL-C and TG in the Japanese, while it was associated with systolic blood pressure in the Koreans, and TG in the Mongolians. In conclusion, an increase in n-3 PUFA was associated with HDL-C and TG in the Japanese and Mongolians, but these beneficial effects were not constant across the three Asian ethnic groups.
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  • Akihisa Hata, Yoko Endo, Yoshiaki Nakajima, Maiko Ikebe, Masanori Ogaw ...
    2007 Volume 49 Issue 3 Pages 217-223
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    The toxicity and carcinogenicity of arsenic depend on its species. Individuals living in Japan consume much seafood that contains high levels of organoarsenics. Speciation analysis of urinary arsenic is required to clarify the health risks of arsenic intake. There has been no report of urinary arsenic analysis in Japan using high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). We performed speciation analysis of urinary arsenic for 210 Japanese male subjects without occupational exposure using HPLC-ICP-MS. The median values of urinary arsenics were as follows: sodium arsenite (AsIII), 3.5; sodium arsenate (AsV), 0.1; monomethylarsonic acid (MMA), 3.1; dimethylarsinic acid (DMA), 42.6; arsenobetaine (AsBe), 61.3; arsenocholine, trimethylarsine oxide, and unidentified arsenics (others), 5.2; and total arsenic (total As), 141.3 μgAs/l. The median creatinine-adjusted values were as follows: AsIII, 3.0; AsV, 0.1; MMA, 2.6; DMA, 35.9; AsBe, 52.1; others 3.5; and total As, 114.9 μgAs/g creatinine. Our findings indicate that DMA and AsBe levels in Japan are much higher than those found in Italian and American studies. It appears that the high levels of DMA and AsBe observed in Japan may be due in part to seafood intake. ACGIH and DFG set the BEI and BAT values for occupational arsenic exposure as 35 μgAs/l and 50 μgAs/l, respectively, using the sum of inorganic arsenic (iAs), MMA, and DMA. In the general Japanese population, the sums of these were above 50 μgAs/l in 115 (55%) samples. We therefore recommend excluding DMA concentration in monitoring of iAs exposure.
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  • Madelon L.M. van Hooff, Sabine A.E. Geurts, Michiel A.J. Kompier, Toon ...
    2007 Volume 49 Issue 3 Pages 224-234
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    The main aim of this study was to establish the convergent and discriminant validity of a single-item measure of daily fatigue ("How fatigued do you currently feel?") in a daily diary context. Convergent validity of our measure was examined by relating it to a validated multiple-item measure of fatigue (Profile of Mood States; McNair, Lorr, & Droppelman, 1971) and to other daily (work-home interference, sleep complaints, work-related effort) and global (fatigue, health complaints, work-home interference, job pressure) measures that are conceptually related to fatigue. Discriminant validity was assessed by relating the single-item fatigue measure to daily (work pleasure) and global (job control, social support, motivation to learn) measures that are conceptually distinct from fatigue. Data were collected among 120 academic staff members, who completed a general questionnaire (tapping the global measures under study) and who took part in a 9-d daily diary study (3 measurements daily). Correlation patterns and multilevel analyses revealed strong and significant associations between the single-item fatigue measure and the variables incorporated to assess convergent validity (especially with the POMS: r=0.80), thus supporting the convergent validity of our measure. Relations with variables included to examine discriminant validity were weak or insignificant, supporting the discriminant validity of the single-item fatigue measure. Despite this study's limitations (i.e., exclusive use of self-reporting, specific sample) we conclude that this single-item fatigue measure offers a valid way to assess daily fatigue.
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  • Kazuya Adachi, Tomotaro Dote, Emi Dote, Go Mitsui, Koichi Kono
    2007 Volume 49 Issue 3 Pages 235-241
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    Cadmium fluoride (CdF) is commonly used as an insulator for ulta high speed mass telecommunications equipment, and there is a considerable risk that industrial workers will inhale CdF particles. Despite the possibility that acute exposure can cause harmful systemic effects, there are no studies to date that address the health consequences of acute CdF exposure. This study therefore aimed to determine the acute lethal dose of CdF and its effects on various target organs, including the liver and kidney. We also determined the effect of CdF on serum electrolytes and acid-base balance. The effective lethal dose was determined and dose-response study was conducted after intravenous administration of CdF in rats. The 24 h LD50 of CdF was determined to be 3.29 mg/kg. The dose-response study used doses of 1.34, 2.67, 4.01 mg/kg CdF. Saline or sodium fluoride solution were used for controles. Severe hepatocellular injury was induced at doses greater than 2.67 mg/kg, as demonstrated by AST and ALT activities greater than 1,500 IU/l in rats injected with a dose of 4.01 mg/kg. Acute renal failure was induced at doses greater than 2.67 mg/kg. Decreased serum Ca, increased serum K and metabolic acidosis were induced at a dose of 4.01 mg/kg. Decreased serum Ca was caused by exposure to ionized F. CdF has the strongest lethal and hepatic toxicity among all Cd containing compounds.
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  • Heungnam Kim, Yasuo Morimoto, Akira Ogami, Hiroko Nagatomo, Masami Hir ...
    2007 Volume 49 Issue 3 Pages 242-248
    Published: 2007
    Released on J-STAGE: June 13, 2007
    JOURNAL FREE ACCESS
    Superoxide dismutases (SODs) are antioxidant enzymes that catalyze the dismutation of superoxide into hydrogen peroxide. There are 3 kinds of isozymes: extracellular superoxide dismutase (EC-SOD), manganese-containing superoxide dismutase (Mn-SOD) and copper- and zinc-containing superoxide dismutase (CuZn-SOD). To examine the expression of SOD isozymes in lungs injured by crystalline silica, we intratracheally instilled male Wistar rats with 2 mg (8 mg/kg) of crystalline silica and investigated the mRNA, protein level and distribution of SOD isozymes in the rat lungs using RT-PCR, western blot analysis and immunostaining, respectively at from 3 d to 180 d of recovery following the exposure. EC-SOD mRNA levels significantly increased from 3 d to 90 d and the EC-SOD protein level was significantly higher after 90 and 180 d recovery in the crystalline silica exposed groups than in the control groups. Mn-SOD increased in silica treated rat lungs at both mRNA and protein levels, peaking at 30 d post-exposure. CuZn-SOD mRNA levels were decreased at 3, 7 and 30 d, and CuZn-SOD protein levels were also significantly lower than the control group at 90 and 180 d recovery. There was prominent EC-SOD immunostaining mainly in the plasma and alveolar macrophages and strong Mn-SOD staining in alveolar macrophages and interstitial cells of the proximal and distal portions of the alveolar duct following crystalline silica exposure. There was less CuZn-SOD staining in epithelial cells at terminal bronchioles in the crystalline silica-exposed group. These findings suggest that these SOD isozymes may be related to lung injury induced by crystalline silica.
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