We investigated whether supervisors' listening attitudes and skills were related to working conditions and psychological stress reactions among their subordinates. The subjects included 41 male supervisors and their immediate subordinates (n=203). The supervisors completed a short version of the Active Listening Attitude Scale (ALAS) consisting of two subscales: Listening Attitude and Listening Skill for Active Listening. The subordinates rated working conditions and their psychological stress reactions using selected scales of the Job Content Questionnaire and the Brief Job Stress Questionnaire. Those subordinates who worked under supervisors with a higher score of Listening Attitude and Listening Skill reported a more favorable psychological stress reaction than those who worked under supervisors with a lower score of Listening Attitude and Listening Skill. Those subordinates who worked under supervisors with a higher score of Listening Skill reported higher worksite support than those who worked under supervisors with a lower score of Listening Skill. Those subordinates who worked under supervisors with a higher score of Listening Attitude reported higher job control than those who worked under supervisors with a lower score of Listening Attitude. A supervisor's listening attitude and skill appeared to affect psychological stress reactions predominantly among male subordinates than among female subordinates. Psychological stress reactions were lower among younger subordinates who worked under supervisors with high listening skill, while no statistically difference was observed among older subordinates. These findings suggest that a supervisor's listening attitude and skill have an effect on working conditions and psychological stress reactions among subordinates and that the effects vary according to the subordinates' sex and age.
Crystalline silica, known as a causal substance of silicosis, has been carefully evaluated for its carcinogenicity and fibrogenicity. In this study, we instilled crystalline silica of two different size (S1.8 :1.80 μm (S.D. 2.0), S0.7 :0.74 μm (S.D. 1.5)) into the trachea of rats to evaluate the size effects of the particles on pulmonary inflammation. S1.8 and S0.7 samples were administered to rats by a single intratracheal instillation (2 mg/ 0.4 ml saline). At three days, 1 wk and 1, 3 and 6 months after the instillation, the blood, bronchoalveolar lavage fluid (BALF), and pulmonary tissues were analyzed. Six images per HE-stained section were digitally captured and examined by the point counting method (PCM). Polymorphonuclear leukocyte (PMN)-in-blood specimens and cytospin specimens from BALF were stained immunohistochemically with BrdU. At six months after the instillation, the effects on inflammatory cells in the pulmonary tissues and BALF tended to be more marked in the rats instilled with S1.8 than those instilled with S0.7. Particularly, clear differences were observed in the number of inflammatory cells in BALF. Even if the particles are of the same chemical composition, the results suggest that, their biological effects vary depending on their particle size. Therefore, when such particles are used in workplaces, strict control systems should be established according to the risks present by different sizes of particles.
Perfluoroisobutylene (PFIB) is produced as a main by-product in large quantities by the fluoropolymer industry. As a highly toxic compound, even the case of brief inhalation of PFIB can result in acute lung injury (ALI), pulmonary edema and even death. To test for any preventive or therapeutic effects of pyrrolidine dithiocarbamate (PDTC), a NF-κB activation inhibitor, against PFIB inhalation-induced ALI, mice were exposed in a flow-past exposure system to PFIB and the prophylactic and therapeutic effects of PDTC were studied. The inhibitory effects of PDTC on ALI, the activation of NF-κB, as well as the expression of cytokines (IL-1β and IL-8) after PFIB exposure were evaluated. The results demonstrated that pretreatment with PDTC (120 mg/kg, 30 min before PFIB exposure) could significantly lower the lung coefficient (wet lung-to-body weight ratio, dry lung-to-body weight ratio, water content in the lung, and lung wet-to-dry weight ratio) and protein content in bronchoalveolar lavage fluid (BALF), but no effects of PDTC were found when PDTC was treated after PFIB inhalation, suggesting a preventative effect rather than a therapeutic effect of PDTC. Furthermore, the above preventative effects of PDTC (when given at 30 min before PFIB exposure) on PFIB-induced lung injury were achieved in a dose-dependent manner. In support of these preventive effects of PDTC, our toxicological studies demonstrated that PFIB-inhalation induced a quick activation of NF-κB (0.5 h post PFIB exposure) and expression of IL-1β and IL-8 (0.5 h and 1 h post PFIB exposure, respectively). Pretreatment with PDTC (120 mg/kg, 30 min before PFIB exposure) resulted in a significant inhibitive effect on the activation of NF-κB (0.5 h post PFIB exposure) and expression of IL-1β and IL-8 (1 h post PFIB exposure). The mortality, the extent of lung injury of the mice indexed by lung coefficients, the content of total protein and albumin in BALF, as well as the lung histopathologic changes, were dramatically alleviated in PFIB exposure after pretreatment with PDTC, clearly suggesting that PDTC has a prophylactic role against PFIB inhalation-induced ALI, and that NF-κB activation might play a central role in initiating an acute inflammatory response and in causing injury to the lungs after PFIB inhalation.
This study aimed to test the possible use of unmetabolized volatile organic compounds (VOCs) in urine as biomarkers of low-level indoor environmental exposure. Twenty-four subjects in 13 dwellings in a prefecture of Japan participated in this study. Air samples of the breathing zone were collected in the living room and bedroom, along with spot urine samples (before bedtime and first morning voids). Toluene, ethylbenzene, xylene isomers, styrene and p-dichlorobenzene in the air and urine samples were measured by gas chromatography/mass spectrometry. For the 21 subjects without solvent exposure at work, there were significant correlations between the time-weighted average air concentrations in the bedroom and morning urinary concentrations for toluene, o-xylene, total xylene and p-dichlorobenzene (correlation coefficients of 0.54, 0.61, 0.56 and 0.84, respectively). Multiple linear regression analysis showed only air VOCs in the bedroom influenced the morning urinary VOC concentrations. We concluded that unmetabolized VOCs in the urine can provide a reliable biological indicator for air VOC exposures in non-occupational environments.
This study investigated the effects on attention performance after exposure to noise and whole-body vibration in relation to subjective noise sensitivity. Sixteen high and 16 low sensitivity male students, as determined by the Weinstein Noise Sensitivity Questionnaire, participated in a within-subjects experiment. Noise and vibration stimuli similar to those usually occurring in forestry vehicles were presented either individually, combined or not at all in four separate sessions lasting approximately 44 min. After exposure, participants completed an attention task and made subjective ratings of alertness. No main effect of noise sensitivity was observed in MANOVA, thus the data was pooled with the data from a pilot study using the exact same procedure without using a noise sensitivity inclusion criterion. The combined data revealed performance degradation in the attention task after exposure to vibration, regardless as to whether it was presented alone or in combination with noise. Increased ratings of alertness after vibration exposure and decreased ratings of alertness after noise exposure were also found. Neither synergistic nor antagonistic effects were observed from the combined noise and vibration exposure.
The objective of this study was to determine the relationship between obstructive sleep apnea-hypopnea syndrome (OSAHS) and overweight combined with hypertension and to examine whether OSAHS in conjunction with overweight and hypertension is associated with daytime sleepiness. In a Japanese workplace of 28,636 employees, 368 men (19-62 yr old), who were anxious regarding their OSAHS symptoms, underwent home pulse oximetry. Of these, 153 men subsequently underwent all-night polysomnography (PSG), and OSAHS was diagnosed in 149. We next classified these 149 men into the following groups: A [Overweight (-)/Hypertension (-), n=41], B [Overweight (-)/Hypertension (+), n=15], C [Overweight (+)/Hypertension (-), n=46], and D [Overweight (+)/Hypertension (+), n=47]. The Epworth Sleepiness Scale (ESS) was used to evaluate daytime sleepiness and the apnea-hypopnea index (AHI) was used to evaluate the severity of OSAHS. The averages of the ESS score and the AHI were compared in each group. Both the average ESS scores and the percentage of ESS scores ≥11 were not significantly different among the groups. The average AHI of group D was the highest among all of the groups and that of group C was significantly higher than those of groups A and B. In all the groups, the OSAHS patients with overweight and hypertension in this study had the highest AHI. The level of daytime sleepiness evaluated by the ESS in this study was almost the same in the OSAHS patients regardless of the degree of overweight or hypertension. These observations suggest that it is necessary to positively recommend PSG to men who are suspected of having OSAHS with overweight and hypertension, even if they do not have daytime sleepiness.
In Japan, consultations concerning child abuse cases are increasing rapidly, and the mental health of child-counseling office workers, who must deal with them, has emerged as an issue. To measure the state of mental health of these workers, and to clarify the characteristics of their job-related stress, we sent a questionnaire to 69 workers of child-counseling offices in Ibaraki Prefecture and obtained responses from 45. (1) Their job environment was characterized as high demand/low control/low reward. (2) The mean score of GHQ-12 of the subjects was 5.9 ± 3.6, indicating a very poor state of mental health. (3) Stress due to physical and verbal assaults by the parties involved in the cases and the psychological burden of intervention were found to be related to their poor mental health. Along with measures to prevent such assaults, training in intervention techniques, supervision, and care for psychological trauma are needed for child-counseling office workers.
We analyzed lead concentrations in bones from both genders of Japanese merchants (including rohnin; masterless samurai) and farmer classes, and compared the findings with those of the samurai class in the Edo period (1603-1867) to clarify gender and hierarchical (or occupational) differences in lead exposure during the Japanese feudal age. Merchant class females had significantly higher lead exposure (90.8 μg Pb/g dry bone; n=20) than males of the same class (39.9 μg Pb/g dry bone; n=31) (p<0.01), indicating a remarkable gender difference in the urban population. In contrast to these high concentrations, males and females of the farmer class living in agricultural (or semi-rural) areas had significantly lower exposure (total mean value; 9.2 μg Pb/g dry bone; n=4) than both genders of the merchant class (p<0.001), and the gender difference was not significant in this class.
Polycyclic aromatic hydrocarbons (PAH) are common air pollutants generated from incomplete combustion. The inhalation of exhaust fumes in urban areas has been suggested to be an additional contributing factor. This study investigated the influence of urban traffic exposure, personal lifestyle factors and metabolic enzyme polymorphisms on the urinary 1-hydroxypyrene (1-OHP) level, approximating exposure to PAH. With consents, 95 male taxi drivers exposed to vehicle exhaust in traffic and 75 male office employees received health interviews and provided urine samples. The results showed taxi drivers had higher urinary 1-OHP than the office employees (mean ± standard deviation were 0.17 ± 0.10 vs. 0.10 ± 0.07 mol/mol creatinine, p<0.001). The average urinary 1-OHP level increased from 0.07 μmol/mol creatinine for non-smoking office employees to 0.17 μmol/mol creatinine for those who smoked more than 20 cigarettes daily. The values for taxi drivers with similar smoking statuses were 0.12 and 0.25 μmol/mol creatinine, respectively. Among non-smokers, taxi drivers still had higher 1-OHP level than office employees (0.12 ± 0.05 vs. 0.07 ± 0.03 μmol/mol creatinine). The subjects with the m1/m2 or m2/m2 genotype of CYP1A1 MspI or GSTM1 deficiency had significantly higher urinary 1-OHP levels than those with other CYP1A1 MspI and GSTM1 genotypes. Multivariate logistic regression analysis showed that taxi drivers (adjusted odds ratio (OR)=5.1, 95% confidence interval (CI)=1.1-13.6), smokers (OR=5.5, 95% CI=1.6-18.4) and subjects with the m1/m2 or m2/m2 genotype of CYP1A1 MspI (OR=9.7, 95% CI=2.7-35.0) had elevated urinary 1-OHP (greater than the overall median value, 0.11 μmol/mol creatinine). The results of this study suggest smoking contributes to the elevated urinary 1-OHP levels in taxi drivers in addition to taxi driving, and the excess level contributed from traffic exhaust and smoke was regulated by the CYP1A1 MspI genotype. Traffic exhaust exposure, smoking and CYP1A1 MspI genotype contributed to the variation in levels of urinary 1-OHP excretion.
Incineration workers are exposed to various pyrolysis products of organic materials, heavy metals and polycyclic aromatic hydrocarbons (PAHs). In this study, the exposure of incineration workers to PAHs was evaluated by measuring urinary metabolites of pyrene and naphthalene. The concentrations of urinary 1-hydroxypyrene (1OHP), a metabolite of pyrene, and 2-naphthol (2NP), a metabolite of naphthalene, were measured among 100 workers in 4 different types of incinerators, both before and after their work shifts. These incinerators were two old types, one modern type and one outdoors. The medians of urinary 1OHP of before and after the work shifts obtained from all workers were 0.067 and 0.044 μg/gCr, respectively; and the medians of urinary 2NP were 7.5 and 10.0 μg/gCr, respectively. A significant increase of 2NP after the work shift was found at one old incinerator. A significant decrease of metabolites was found at the other old incinerator. Significant correlations were found between urinary metabolites and cigarettes smoked per day. The effect of smoking on urinary metabolite levels was also important. Significant correlations were found between urinary 1OHP and 2NP levels in all workers. In multiple regression analysis smoking habit and incinerator type were found as significant factors. The improvement of the work environment, through decreasing exposure to both tobacco smoke and hazardous work shift-related substances, should be an occupational health aim.