In order to examine the short-, medium- and long-term effects of cerium dioxide particles of different sizes on the lung, 10-wk-old male Wistar rats were administered a physiological saline solution with a suspension of coarse or fine particles of cerium dioxide at 34 mg/kg body weight by a single intratracheal instillation. Lungs were examined with cellular and biochemical analyses of the bronchoalveolar lavage (BAL) fluid and histopathology on different days after the instillation. Geometric mean and geometric standard deviation of the diameter were 3.90 μm ± 1.93 for the coarse (Ce-C) particles, and 0.20 μm ± 1.20 for the fine (Ce-F) particles. There were no lesions in the lung in the Ce-C-instilled group at any time point after the instillation. The instillation of Ce-F particles primarily induced inflammation, granulomas, mobilization and impairment of alveolar macrophages (AMs), and pulmonary alveolar proteinosis, together with very slight degrees of Type II epithelial cell hyperplasia and of collagen deposition. The pulmonary toxicity of Ce-F-instilled rats was found to be markedly enhanced in sharp contrast to that of Ce-C-instilled rats on the basis of equal mass concentration, suggesting clear dependence of the pulmonary toxicity on numbers and sizes of particles. Causative factors for the pulmonary alveolar proteinosis are discussed with reference to the impaired AMs.
This study was conducted to determine whether job demand played a role as a risk factor of cardiovascular diseases by comparing changes of blood pressure, heart rate and rate pressure product (RPP) showing myocardial oxygen consumption (MVO2) according to levels of job demand. This cross-sectional study divided 177 male white-collar workers without a cardiovascular or metabolic disease according to their job demand and analyzed their body composition and results of graded exercise testing. There was no significant difference in height, body weight, body mass index (BMI), waist to hip ratio (WHR) and body fat percentage according to job demand. Maximal oxygen consumption (VO2max) and anaerobic threshold (AT) also did not show a significant difference. However, systolic blood pressures at the seventh and eighth stages over AT during exercise were significantly different and RPP was found to have a significant difference overall according to the job demand (p<0.05). These results meant that job demand affected systolic pressure in physical activities or at exercise intensity over AT and reduced energy efficiency of myocardium during physical activities. The results suggest that high job demand may be a risk factor of cardiovascular diseases.
The Risk Level Based Management System (RLBMS) is an occupational risk management (ORM) model that focuses occupational safety, hygiene, and health (OSHH) resources on the highest risk procedures at work. This article demonstrates the model's simplicity through an implementation within a heavily regulated research institution. The model utilizes control banding strategies with a stratification of four risk levels (RLs) for many commonly performed maintenance and support activities, characterizing risk consistently for comparable tasks. RLBMS creates an auditable tracking of activities, maximizes OSHH professional field time, and standardizes documentation and control commensurate to a given task's RL. Validation of RLs and their exposure control effectiveness is collected in a traditional quantitative collection regime for regulatory auditing. However, qualitative risk assessment methods are also used within this validation process. Participatory approaches are used throughout the RLBMS process. Workers are involved in all phases of building, maintaining, and improving this model. This worker participation also improves the implementation of established controls.
To evaluate the effects of cold exposure on the musculoskeletal system, two surveys on the subjective musculoskeletal symptoms among male electricians working in the buildings under construction were performed in winter (N=74) and summer seasons (N=83). A self-administered questionnaire was used to collect information on age, occupational career, working habit, present illness, and subjective musculoskeletal symptoms. Mean age, occupational career and daily smoking of the supervisors were significantly higher than those of the other subjects. In general, prevalence rates of stiffness, numbness, pain and Raynaud's phenomenon in the fingers, finger cold sensation, dull movement of the fingers, pain in the wrist, knee joint pain, pain and numbness in the foot and foot cold sensation in winter were significantly higher than those in summer. These results were marked especially in the workers except supervisors. In winter, there were no significant differences in the prevalence rates of subjective musculoskeletal complaints between the supervisors and the other workers. On the other hand, in summer, prevalence of stiffness and pain in the shoulder, stiffness and pain in the neck, dullness and pain in the arm, finger cold sensation, low back dullness and low back pain in the supervisors were significantly higher than those in the other workers. These results suggest that effects of cold on the musculoskeletal symptoms markedly appeared in the workers except supervisors.
Chrysotile asbestos fiber, imported from Russia, is used mainly for manufacturing purposes in Iran and related risks in the form of asbestosis and cancer were studied. Occupational exposure of all male workers (61 persons) to asbestos in a brake shoe factory was monitored. Cumulative exposures were determined through multiplication of typical exposure and work history. Risk assessment of exposed workers was estimated by risk criteria recommended by the American Environmental Protection Agency. Measurement of lung function parameters such as forced expiratory volume in one second (FEV1), forced volume capacity (FVC) and FEV1/FVC of exposed workers were obtained. Unadjusted correlation and adjusted correlation analysis for support of the association between cumulative exposure (fiber/ml-yr) and lung function parameters were used. Exposure of majority of exposed group was far greater than the occupational exposure limits (0.1 fiber/ml) in the range of 0.06-8.06 fiber/ml. Cumulative exposures in the range of 0.02 to 110.77 fiber/ml-yr were obtained. According to the risk criteria stated by ATSDR, risk assessment of workers in term of fibrotic changes was predicted for at least 24.6 percent of the exposed subjects. Again, according to the lung cancer risk criteria stated by EPA, 59 percent of workers will have excess risk. Negative correlation between lung function parameters (FEV1, FEV1/FVC) and cumulative exposures adjusted for age and BMI were significant (p<0.05).
In order to recognize the problems associated with the transport mechanism of containment during the ventilation process of a laboratory fume hood, a transparent, full scale chemical fume hood is constructed for experimental studies. Distributions of mean velocity and velocity fluctuation in the sash plane are measured using a thermal anemometer. Flow patterns and tracer-gas concentration leakages are respectively diagnosed via the laser-assisted flow visualization method and the EN 14175-3 test protocol. The magnitudes of measured velocity fluctuations exhibit a sharp peak along the perimeter of the sash opening. The results of flow visualization verify that the elevated turbulence fluctuations are induced by the boundary-layer separation when the flow passes over the edges of sash perimeter. The tracer gas experiment shows that the regions where high degree containment leakages detected are located along the perimeter of hood aperture. Eleven commercial hoods which are claimed with fine aerodynamic design are further tested for confirmation of these observations. The results show similar correlations. Conclusions thus are made that large-scale vortex structures occurring around the perimeters of hood aperture due to the boundary-layer separation could induce strong turbulence, and therefore enhance dispersion of the hood containment.
Activated carbon is an elemental material used for hygienic applications, particularly as an adsorbent for harmful gases and vapors. In Japanese industrial and occupational hygiene, activated carbon produced from coconut shell is a traditional and popular adsorbent material due to its excellent adsorption ability and cost advantage. In this research, in order to clarify the effect of the preliminary content of moisture on the adsorption capacity in detail, we prepared several coconut shell activated carbons which were preconditioned by equilibration with moisture at different relative humidities. We measured their adsorption capacities as breakthrough times for 6 kinds of organic vapor, and attempted to determine the relationships between the relative weight increase of water adsorption and the decrease of adsorption capacities of the activated carbon specimens for the organic vapors. The procedure of the quantitative evaluation of the effect of moisture and the results are useful for practical applications of activated carbon, particularly those used as adsorbents in workplaces.
This study aimed to clarify the role of blood lead level (Pb-B) as one of the cardiovascular risk factors. To evaluate the cardiovascular risk the second derivative finger photoplethysmogram (SDPTG) was used. The subjects comprised of 420 male bus drivers in Thailand. The subjects' age ranged from 20 to 60 yr. Mean age (± standard deviation) were 41.6 (± 7.7) yr. Mean working years was 8.8 (± 6.8) yr. Pb-B ranged from 2.5 to 16.2 μg/dl with the mean Pb-B of 6.3 (± 2.2) μg/dl. The mean of aging index of SDPTG (SDPTG-AI) were -0.50 (± 0.30). The SDPTG-AI increases with age, Pb-B, smoking and alcohol consumption. There was significant correlation between Pb-B and SDPTG-AI after controlling for age, body mass index and lifestyle factors. These results suggest that Pb-B is possibly an independent cardiovascular risk factor for bus drivers exposed to lower level of lead.
Organizational justice has recently attracted attention as a predictor of employee mental and physical health. However, the lack of a Japanese translation of the original English-language organizational justice scale (OJS) has precluded its application in Japan. The present study aimed to develop Japanese version of the measure of organizational justice. We translated the original questionnaire, which is comprised of 20 items, from English to Japanese. The OJS is made up of four distinct dimensions: procedural, distributive, interpersonal and information justice. A total of 229 employees responded to the Japanese version of the OJS (OJS-J), the effort-reward imbalance (ERI) model and the Kessler Psychological Distress Scale (K10). To assess construct validity, we recorded job satisfaction using the visual analog scale (VAS). Our exploratory factor analysis supported the four-factor structure model of OJS-J. Correlation coefficients between the OJS-J and ERI, K10 and VAS were statistically significant, indicating a reasonable degree of construct validity. Obtained internal consistency was markedly high (Cronbach's alpha was 0.96), and test-retest reliability as analyzed with an intraclass correlation coefficient was 0.91. These results suggest that the OJS-J is a reliable and valid measure that may be suitable for use as a predictor of employee health in the Japanese work place.
Excessive demands on Operation Room (OR) nurses may result in high rates of Musculoskeletal Disorders (MSDs). This study was conducted among Shiraz city hospital OR nurses to determine the prevalence of MSDs and to examine the relationship between perceived demands and reported MSDs. In this cross-sectional study, 375 OR nurses participated (response rate: 80%). The Nordic Musculoskeletal Disorders Questionnaire and the Job Content Questionnaire were used as collecting data tools. Lower back symptoms were found to be the most prevalent problem in the OR nurses studied with a past year prevalence of 60.6%. Perceived physical demands were significantly associated with musculoskeletal symptoms (odds ratio ranged from 2.04 to 7.24). Manual material handling (MMH) activities were most frequently associated with reported symptoms. Association was also found between perceived psychological demands and reported symptoms (odds ratio>1.68). Based on the findings of this study, it could be concluded that operation room was not only a physically but also psychologically demanding environment. Any interventional program for preventing or reducing MSDs among OR nurses had to focus on reducing physical demands, particularly excessive MMH demands as well as considering psychological aspect of working environment.
To investigate the interactions between safety climate, psychosocial issues and Needlestick and Sharps Injuries (NSI), a cross-sectional study was undertaken among nurses at a university teaching hospital in Japan (89% response rate). NSI were correlated with various aspects of hospital safety climate including supporting one another at work, the protection of staff against blood-borne diseases being a high management priority, managers doing their part to protect staff from blood-borne disease, having unsafe work practices corrected by supervisors, having the opportunity to use safety equipment to protect against blood-borne disease exposures, having an uncluttered work area, and having minimal conflict within their department. In conclusion, this study has demonstrated the importance of hospital safety climate in Japanese health care practice, particularly its relationship with NSI. Although the provision of safer devices remains critical in preventing injuries, ensuring a positive safety climate will also be essential in meeting these important challenges for nurses' occupational health.
Peroxisome proliferator-activated receptor-α (PPARα) has been suggested to protect against chemically induced hepatobiliary injuries in rodents. This function could mask the potential toxicities of perfluorooctanoic acid (PFOA) that is an emerging environmental contaminant and a weak ligand of PPARα. However its function has not been clarified. In this study, PFOA was found to elicit hepatocyte and bile duct injuries in Pparα-null mice after 4 wk treatment with PFOA ammonium salt (0, 12.5, 25, 50 μmol/kg/d, gavage). In wild-type mice, PFOA caused major hepatocellular damage dose-dependently and minor cholangiopathy observed only at 25 and 50 μmol/kg. In treated Pparα-null mice, PFOA produced marked fat accumulation, severe cholangiopathy, hepatocellular damage and apoptotic cells especially in bile ducts. Oxidative stress was also increased 4-fold at 50 μmol/kg and TNF-α mRNA was upregulated more than 3-fold at 25 μmol/kg in Pparα-null mice. Biliary bile acid/phospholipid ratios were higher in Pparα-null mice than in wild-type mice. Results from these studies suggest that PPARα is protective against PFOA and have a critical role in drug induced hepatobiliary injury.
The purpose of this study was to observe changes in electromyographic activity appeared in shoulder and scapular muscles when one wears no wrist extension orthosis, short wrist extension orthosis and long wrist extension orthosis when performing two model assembling operations. The study subjects were 16 adults who use right hand and did not have any functional disorder on their wrist or the upper limbs without any orthopedic surgery. The study subjects were asked to do the two model assembling operations without wrist extension orthosis, with a short wrist extension orthosis and with a long wrist extension orthosis. As a result of repetitive assembling operation that requires shoulder movement, electromyographic activity in upper trapezius and serratus anterior increased significantly when the subjects wore the short and long wrist extension orthoses compared to none. When the subjects performed repetitive assembling operation that requires shoulder stability, electromyographic activity in upper trapezius, lower trapezius, serratus anterior, and anterior deltoid showed significant increase when they wore the short and long wrist extension orthoses compared to none. Especially, the upper trapezius showed significantly high electromyographic activity when they wore the long wrist extension orthosis compared to a short one.
Polychlorinated biphenyls (PCBs) are known as environmental contaminants that may cause abnormal effect in various organs. We have previously reported that low dose of hydroxylated PCBs (OH-PCBs) including 4'-OH-2',3,3',4',5'-pentachloro biphenyl (4'-OH-PCB 106), suppressed thyroid hormone (TH) receptor (TR)-mediated transcription on several artificial TH-response elements (TREs) due to partial dissociation of TR from TRE. In the present study, we examined the effect of OH-PCB on TR-mediated transcription on native TRE-containing promoter, using malic enzyme (ME)-TRE. Transcriptional activity was measured by transient transfection based reporter gene assay in CV-1, fibroblast-derived clonal cells. TR-mediated transcription was suppressed by 4'-OH-PCB106 significantly and 4'-OH-PCB187 weakly, but not by 4'-OH-PCB165. To examine TR-TRE bindings under exposure of 4'-OH-PCB106, electrophoretic mobility shift assay (EMSA) was performed. In EMSA, TR was dissociated from ME-TRE by 4'-OH-PCB106. These findings suggest that OH-PCB may disrupt TR-mediated transcription on native promoter.
Expanded perlite has been assumed as simple nuisance, however during an accidental spill out in Taiwan, among 24 exposed workers followed for more than 6 months, three developed persisted respiratory symptoms and positive provocation tests were compatible with reactive airway dysfunction syndrome. During simulation experiment expanded perlite is shown to be very dusty and greatly exceed current exposure permission level. Review of literature and evidence, though exposure of expanded perlite below permission level may be generally safe, precautionary protection of short term heavy exposure is warranted.
Workers service the lavatories of commercial aircraft approximately 11 million times per year in the United States and may have exposure to the spectrum of pathogenic viruses, bacteria and parasites potentially found in human waste. An industrial hygiene walk-through of the workplace was conducted by an interdisciplinary occupational health and safety team, and lavatory waste operators and supervisors and the process was observed. Exposure to untreated waste can occur through dermal, ingestion, and inhalation in quantities ranging from droplets to large spills. Several engineering and administrative measures were advised to minimize worker exposure, including the effective locking of a critical valve, and a mechanism for communicating valve locking problems.