Mesothelioma incidence varies markedly from one country to another. The highest annual crude incidence rates (about 30 cases per million) are observed in Australia, Belgium, and Great Britain. A lot of data indicate a relationship between mesothelioma and asbestos. The hot areas for mesothelioma exactly correspond to the sites of industries with high asbestos use, such as shipbuilding and asbestos-cement industry. However, in many countries with high asbestos consumption, mesothelioma incidence is low. The reasons for this fact are not clear. The latency periods elapsing between first exposure to asbestos and development of mesothelioma are mostly longer than 40 yr. An inverse relationship exists between intensity of asbestos exposure and length of the latency period. Mesothelioma generally develops after long-time exposures to asbestos. Some recent studies show that the risk increases with the duration of exposure. Possible co-factors in the pathogenesis of asbestos-related mesothelioma include genetic predisposition, diets poor in fruit and vegetables, viruses, immune impairment, recurrent serosal inflammation. The study of co-morbidity in mesothelioma could give an insight into the pathogenesis of the tumor. While a levelling-off in mesothelioma incidence has been registered in some countries, a worsening of the epidemic is predictable in large parts of the world.
Studies were conducted to examine the effect of pre and post-treatment of selenium in mercury intoxication (20 μmole/ kg b.w. each given intraperitoneally) in mice in terms of lipid peroxidation (LPO), glutathione (GSH) content, activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and mercury concentration in liver, kidney and brain. No significant alteration was observed in all the organs examined after mercury or selenium treatment in LPO and GSH but administration of selenium (pre and post) resulted in an increase in the level of LPO and GSH. The activity of SOD was depleted in liver and kidney while that of GPx was lowered in liver of mercury exposed animals. Selenium administration resulted in restoration of the depletion of these enzymatic activities. The activity of CAT in liver and brain was enhanced both in mercury and selenium treated animals. Administration of selenium significantly arrested enhanced CAT activity. Kidney showed the highest mercury concentration among the organs examined. Administration of selenium resulted in further enhancement of mercury concentration in the tissues. An increase in selenium level in liver was observed after mercury treatment, which was also restored by mercury selenium co-administration. Our results indicate that the prooxidant effect of selenium was greater by its pretreatment.
Motor vehicle traffic is the main emission source of benzene. We undertook this study in order to compare benzene exposure and urinary levels of trans,trans-muconic acid (t,t-MA) in taxi drivers and petrol station workers. Air benzene levels were analyzed with gas chromatography using a Flame Ionization Detector. t,t-MA was extracted from urine and analyzed using high performance liquid chromatography. Significant differences in levels of urinary t,t-MA were found in drivers and petrol station workers when compared to a control group (p<0.05). Correlation coefficients between benzene in air and t,t-MA for petrol station workers and drivers were 0.65 and 0.30, respectively. The concentration of benzene in the breathing zone of petrol station workers was 2-3 times higher than drivers, and also 3 times greater than a threshold level (0.5 ppm) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The lowest benzene concentration at which urinary t,t-MA increased to a measurable level was approximately 0.17 ppm. In conclusion our results suggested that high benzene levels are emitted in petrol stations in west Iran. t,t-MA analysis was able to separate those exposed from the non-exposed benzene group when benzene in the breathing zone of subjects was greater than 0.17 ppm.
The aim of this study was to identify factors related to the health-related quality of life (HRQOL) of caregivers providing continuing home care for the impaired elderly focusing mainly on care managers' support given to caregivers. Two interviews over a course of 12 months were conducted with 42 caregivers. The questionnaire items for the caregivers included demographic variables, HRQOL, the satisfaction level of care managers, coping ability, and depressive state. For the impaired elderly, the questionnaire items included demographic variables, abilities of activities of daily living, dementia assessment, and depressive state. The mean age of the caregivers was 66.1 ± 8.8. By logistic regression analysis with HRQOL as a dependent variable, the caregivers' physical QOL was significantly related to the depressive state of impaired elderly and the caregivers' satisfaction with their care manager, whereas the caregivers' mental QOL was significantly related to the caregivers' sense of coherence and satisfaction with their care manager. These results suggest that the care managers' support to caregivers who provide continuing home care is important for caregivers' HRQOL.
Objective is to evaluate the impact of occupational exposure to lignite dust on respiratory system. 103 blue-collar workers exposed to lignite dust and 62 controls completed a questionnaire on respiratory symptoms and underwent spirometry. Levels of lignite dust in workplace were measured. Univariate and multivariate analysis of the data were performed. The concentration of lignite dust varied from 0.6 to 1.4 mg/m3. Current smokers and workers exposed to lignite dust presented higher prevalence of chronic bronchitis symptoms and of FEV<80% and FEV1/FVC<70%. Multivariate analysis has shown that smoking and occupational exposure to lignite dust were independent predictors of chronic bronchitis symptoms, as well as of an obstructive ventilation pattern. Further analysis showed that exposed workers who were current smokers presented a five fold rate for developing an obstructive ventilation pattern in comparison to exposed workers non currently smokers. Occupational exposure to lignite dust and smoking were independent determinants of chronic bronchitis symptoms and obstructive ventilation pattern. There is some evidence for a combined effect of smoking and lignite dust exposure on respiratory system.
The objective of the present study is to investigate the association between various occupational stressors and heavy drinking among male Japanese workers in different age groups. Using the Generic Job Stress Questionnaire, 13 occupational stressors and 2 workplace support indicators were assessed. The questionnaire survey was conducted of 25,104 workers, and the present study analyzed the data from 17,501 male workers. Heavy drinking was defined as weekly alcohol consumption of >275 g, and a total of 1,131 men (6.5%) were classified as heavy drinkers. After adjusting for shift work, occupational class, marital status and smoking, heavy drinking was related to "support from supervisor" for the 18-29 and 50-72 yr-old groups. For the 30-39 yr-old group, heavy drinking was related to "intragroup conflict", "job control" and "cognitive demands." For the 40-49 yr-old group, heavy drinking was related to "physical environment", "quantitative workload" and "underutilization of abilities." The present study clarified that certain occupational stressors relate to heavy drinking, and that this association varies among different age groups.
The toxic effects of man-made mineral fibers (MMMFs) have been evaluated by cell magnetometry using alveolar macrophages (AMs). Recently, on the other hand, the murine macrophage cell line, RAW 264.7, became available and has been used as an in vitro model of AMs. The objective of this study was to determine whether or not cell magnetometry using RAW 264.7 cells can be used to evaluate the toxic effects of MMMFs. RAW 264.7 cells were exposed to one of the MMMFs, potassium octatitanate (PT) or silicon carbide whisker (SiC) at 0, 20, 40 and 60 μg/ml, or chrysotile as a positive control at 0, 15, 20 and 25 μg/ml. The toxic effects of fibers were evaluated by cell magnetometry and LDH assay. For this comparison, AMs were also exposed to chrysotile fibers (CF). In the RAW 264.7 cells exposed to PT 20, 40, 60 or SiC 20, 40, 60, CF 15, 20 and 25 μg/ml, significant delayed relaxation were observed compared with the respective control. In the LDH assay, significant increases in LDH in the supernatant of the cells exposed to PT 20, 40, 60, SiC 20, 40, 60 and CF 15, 20, 25 μg/ml were observed. In AMs exposed to CF 20, 25μg/ml significant delayed relaxation and significant increases in LDH compared with the control were observed. The levels of MMMFs that induced significant differences were similar for cell magnetometry and LDH. The levels of CF that induced significant differences in cell magnetometry and LDH were identical for RAW 264.7 cells and AMs. Our results suggest that cell magnetometry using RAW 264.7 cells is adequate to evaluate the cytotoxicity of exposure to MMMFs.
The present study investigates the relationship between psychosocial work factors and health-related quality of life (HRQOL) in male automotive assembly plant workers in Malaysia. Materials and Methods: A total of 728 male workers were recruited in March-July 2005 from 2 major automotive assembly plants in Selangor and Pahang. In this cross-sectional study, information on socio-demography, psychosocial work factors using the 97-item Job Content Questionnaire (JCQ) and an abbreviated 26-item version of the World Health Organization Quality of Life-Brief Version (WHOQOL-BREF) questionnaire containing 4 domains (physical health, psychological, social relationship, and environment) was self-administered to all workers involved. Results and Conclusion: The prevalence of reported good or very good overall HRQOL and general health was 64.9% and 53.7%, respectively. Multiple linear regression analysis indicated that created skill was positively associated with physical health and psychological domains; whilst, skill discretion was positively associated with social relationship and environment domains. Social support was positively associated with physical health and environment domains; whilst, co-worker support was positively associated with psychological and social relationship domains. Job insecurity and hazardous condition were negatively associated with all domains, whilst psychological job demands was negatively associated with the environment domain of HRQOL.
Grain storage depot workers suffer from different respiratory problems after getting the exposure to storage grain dust. Which is a mixture of pesticides, fungi, silica, bacteria, spores, storage mites, animal hairs, pollens etc. The present study was under taken to evaluate the fungal spore concentration in summer and winter season as well as the pulmonary function status of the workers; studies are limited in our country. In summer and winter seasons, air sampling was done to measure the airborne fungal spore concentration inside the godowns by Rotorod sampler, UK. Aspergilla, Alternaria, Drechslera, Epicoccum, Nigrospora, Periconia were very much common and found higher in winter compared to summer. The respiratory functional status was assessed in two groups of workers of the same storage grain depot (total n=316) in summer (n=136) and in winter (n=180). List of the workers was collected from the authority and randomly selected every alternate worker and divide them for the studies in summer and winter seasons. Slow Vital Capacity (SVC), Forced Vital Capacity (FVC), and Peak Expiratory Flow Rate (PEFR) were recorded and Forced Expiratory Volume in one second (FEV1), FEV1% and different flow rates were calculated. The Immunoglobulin- E (IgE) level in the blood serum was assessed on post shift pulmonary function tests (PFT) decreased workers. The age, height and weight of the same categories of workers of both studies are highly comparable. Mean PFT values in summer found higher than winter. A gradual decrement of values were found as age was increased but not with duration of exposure. Post-shift PFT was carried in 21.8% (69) workers of which 46.4% (32) workers showed the decrement of values. The serum IgE level of the post-shift PFT decreased subjects was found more than 250 IU/ml in 53.1% (17) workers. Restrictive, obstructive and combined types of respiratory impairments were noticed among the workers. Presence of different spores in varying concentration in the working atmosphere may be responsible for the post shift decrement of PFT, allergic symptoms, high IgE level and respiratory impairments among the workers.
This investigation used a standing dummy on slippery and non-slippery surfaces with accelerated movements of a floor to simulate falling backward events. The results revealed the duration of falling, head impact velocity, etc., which are valuable for guiding the development of personal protective equipment, such as wearable airbags. The mechanism, by which a dummy falls backwards due to abrupt accelerated movements of a floor, was studied. A small linear accelerator was designed to apply a series of 20 combinations of step-shaped accelerations of varying durations to cause a standing dummy to fall backwards. Two flooring surfaces, namely, a smoothed aluminum surface sprayed with mould lubricant and a surface with abrasive materials, were used. Ankle, knee and hip joints of the dummy were adjusted in fixed or unfixed positions. When the dummy fell backwards like a rigid body, the head impact velocities were almost constant at around 22 to 23 km/h, and the mean duration of falling to the ground was 0.83 s, when standing on a slippery surface, and 0.98 s when standing on a non-slippery surface. The duration of falling to the ground tended to converge at 0.8 s as the maximum velocity of accelerated movements of the floor increased, irrespective of the frictional properties of the flooring surfaces.
In order to clarify the relationships between lifestyle behaviors and mental health status in Japanese workers, the 28-item General Health Questionnaire (GHQ-28) and Zung's Self-rating Depression Scale (SDS) were administered to 254 male factory workers; further, eight of their personal health practices were surveyed using the Health Practice Index (HPI). Few studies have used the GHQ-28 and SDS simultaneously; moreover, to date, no study has included the lifestyle factors in these scales. We used these tools for the concurrent assessment of mental health status and classified the subjects into high-risk and low-risk groups. The GHQ-28 and SDS scores correlated negatively with the HPI scores. In the older age group, these scores decreased significantly corresponding to an increase in the total number of favorable lifestyle practices followed. Significant relationships were observed between the GHQ-28 subscales and the HPI. Multiple logistic regression analysis revealed that four of the eight health practices surveyed were significantly related to the mental health status in all subjects. Thus, good health practices appear to be closely associated with good mental health status. However, to establish our results, larger study populations are required for further studies in various occupational fields.
To investigate the effect of micro and macro stressors in the work environment on the subjective health status and productive behavior of computer professionals, we conducted a web-based investigation with Japanese IT-related company employees in 53 company unions. The questionnaire consisted of individual attributes, employment characteristics, working hour characteristics, company size and profitability, personal characteristics (i.e., Growth Need Strength), micro and macro stressors scale, and four outcome scales concerning the subjective health status and productive behavior. We obtained 1,049 Japanese IT-related company employees' data (response rate: 66%), and analyzed the data of computer engineers (80%; n=871). The results of hierarchical multiple regressions showed that each full model explained 23% in psychological distress, 20% in cumulative fatigue, 44% in job dissatisfaction, and 35% in intentions to leave, respectively. In micro stressors, "quantitative and qualitative work overload" had the strongest influence on both the subjective health status and intentions to leave. Furthermore, in macro stressors, "career and future ambiguity" was the most important predictor of the subjective health status, and "insufficient evaluation systems" and "poor supervisor's support" were important predictors of productive behavior as well. These findings suggest that improving not only micro stressors but also macro stressors will enhance the subjective health status and increase the productive behavior of computer professionals in Japan.
This study discusses the workplace ergonomic issues in highway construction, and the safe work practices associated with the prevention of ergonomic-related injuries and illnesses in the construction field. In order to achieve the study objectives, a survey was designed and sent to Wisconsin based construction contractors. To design an adequate questionnaire, the research team first conducted a pilot study. The findings from the pilot survey provided a clear direction in creating the final survey. The survey results indicated that hand and finger injuries due to cutting operations and back injuries due to the manual handling of heavy materials to be the most frequent construction task/injury combination. All of the construction firms surveyed had a safety program; however, most of the contractors did not have a site-specific ergonomics program. The construction workers were usually walking/working on the ground, ladder and scaffold, and spent significant amount of time for the manual lifting or carrying heavy materials. The findings from this study may assist safety and health professionals in the construction industry in making effective changes for improving health and productivity.
Severe abdominal colic because of lead poisoning is an uncommon condition in adults. The diagnosis of lead toxicity is often delayed and abdominal pain is mistaken for acute abdomen. We describe three blood brothers who were involved in pottery glazing and suffered from repeated episodes of severe abdominal pain, nausea, vomiting, constipation and anemia due to lead toxicity. The patients had a history of several hospitalizations and one or two unnecessary laparotomies. One patient had wrists drop and weakness of the fingers extensors. All three patients had microcytic microchromic anemia with basophilic stippling of the erythrocytes, lead lines in X-ray of the knee joint and high blood lead levels. A diagnosis of lead poisoning was made and a course of chelating treatment started. Motor neuropathy, anemia and all gastrointestinal symptoms disappeared. Our report highlights the importance of taking a detailed occupational history and considering lead poisoning in the differential diagnosis of acute abdominal colic of unclear cause.
High level of exposure to manganese (Mn) can cause a clinically and pathophysiologically distinct syndrome from idiopathic Parkinson's disease (PD). We describe the clinical features and results of [123I]-fluoropropyl (FP)-CIT SPECT of a liver cirrhotic with atypical parkinsonism. The patient developed atypical parkinsonian features associated with elevated blood Mn from hepatic dysfunction. [123I]-FP-CIT brain SPECT images of dopamine transporter (DAT) demonstrated overall normal range of DAT uptake in the striatum although there were scattered small hypodense regions. The globus pallidum had increased signal on T1-weighted magnetic resonance imaging (MRI). All these findings are compatible with those of manganism, and are remarkably different from that in PD.