The aims of the present study were to determine the effects of passive heat exposure on serum lipid concentrations in healthy young Japanese males and to analyze the relationship between subjects' physical characteristics and the extent of change in serum lipid concentrations. Thirteen subjects with mean ages of 22.6 ± 1.0 (mean ± SE) years were each exposed to control temperature (Tc: 25.2 ± 0.0°C), moderate (Tm: 35.5 ± 0.2°C) and high temperature(Th: 39.8 ± 0.1°C), at a relative humidity of 60.3 ± 1.2% for one hour. Each exposure was carried out on a different day in random sequence. Blood samples were collected just before, during and after the exposure, and serum lipid concentrations were analyzed. In the Tc condition, the concentrations of total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), triglyceride (TG), and free fatty acid (FFA) did not change significantly. In the Tm condition, HDL-C increased significantly after the exposure and FFA increased during and after exposure. While in the Th condition, TC and TG decreased significantly during and after exposure, and LDL-C decreased during exposure. The correlation between changes in serum lipid concentrations and physical characteristics was analyzed if lipid concentrations changed significantly during or after exposure, but no significant correlation was found. The results indicate passive heat exposure has an effect on serum lipid concentrations which is independent of physical characteristics.
Past studies on respirator fit or performance have mostly been done for Whites or male subjects, and little attention has been paid to minorities and Asians. To fill this gap, this study was designed to provide facial anthropometric data for Koreans and to analyze the association between facial dimensions and respirator fit factors for three brands of quarter-mask respirators, two domestic and one imported brand, using a PortacountTM 8020. A total of 110 university student subjects, 70 males and 40 females volunteered for participation in the study. The results of this study showed that Korean males and females have different facial dimensions as compared with those of White males and females. Unexpectedly, the imported respirator performed better than the domestic respirators. Males were found to achieve better respirator fit than females regardless of respirator brands tested. The regression analysis found no common prognostic variables with the three respirator brands studied. A stepwise logistic regression analysis was conducted to find predictive facial dimensions with respirator fits. Some facial dimensions were found to be statistically significant, but these dimensions are different from the traditionally recommended facial dimensions of face length and lip width for quarter mask. To improve respirator fit for Koreans, these different facial characteristics need to be considered in the design of quarter mask respirators.
Blood samples were collected from 113 subjects (56 males and 57 females) living in the district of Alfenas, in southern Minas Gerais state, Brazil, to establish reference values for deltaaminolevulinic acid dehydratase activity (ALA-D, EC 126.96.36.199). The state of health of the population was confirmed by hematological and biochemical parameters analyzed in blood and urine samples. ALA-D determination was performed according to the Berlin & Schaller spectrophotometric method. Distribution may be regarded as according to normal distribution and reference values obtained, in μmol. min-1. L-1 erythrocytes, were: mean (± SD) = 54.5 (± 9.8); 95% confidence interval = 52.7-56.4; lower reference value (mean-2 SD) = 34.9. Mean ALA-D activity was higher than any other published elsewhere and the reference values established are useful as a baseline for evaluating ALA-D activity when monitoring persons exposed to lead. Age, gender, drinking, or smoking did not significantly alter (Student t-test, p≤0.05) the reference values for ALA-D.
We present the performance of a new push-pull ventilation system for sheet-adhesive work inside the body of a sightseeing coach. The target sightseeing coach was 12 m long, 2.5 m wide and 2 m high from floor to ceiling. We made a prototype of an airflow system and a half-scale model of the bus-body. The half scale model was 6 m long, 1.25 m wide and 0.965 m high. The push-pull ventilation system and half-scale model were used to evaluate the flow distributions inside the model. We also measured the concentration of xylene and methanol vapors during simulated sheet-adhesive work. As a result, it was found that the best combination was a the push flow of 24 m3/min and a pull flow of 78 m3/min in this model, and the flow velocity in the model was less than 1 m/s. This system is potentially applicable to any interior work for not only bus-bodies but also train and airplane bodies, which have elongated and confined space with many openings.
Particle stimulated chemiluminescence (CL) production by human polymorphonuclear leucocytes (PMN) has been utilized to evaluate the pathogenicity of mineral and glass fibers with the understanding that reactive oxygen metabolites (ROM) production as measured by CL is etiopathogenically related to fiber toxicity. In the present study to investigate the specific pathogenic role of fiber number and dimensions, CL production from PMN exposed to anthophyllite asbestos mineral and glass fiber samples milled for different time periods was measured. Almost all the fibrous particles in the glass fiber sample were destroyed after milling for 30 minutes. With anthophyllite, the total number of fibrous particles remained almost constant for up to 240 minutes of milling, although the size of fibrous particles was reduced. CL produced by the same mass of glass fiber was elevated after milling for 15 minutes, but then declined when the milling time was further increased. Similarly, with anthophyllite, the production of CL was elevated at the first period of milling for 30 minutes, but then declined at the longer milling times. The level of CL produced was not correlated to the total number of fibrous particles, for both the glass fiber and the anthophyllite samples. Likewise for the glass fiber and anthophyllite samples, no specific range of fiber dimension was correlated to the peak hight CL production. These findings indicate that neither the total number, nor the specific range of fiber dimension solely determines CL production. As a consequence, it may be concluded that other physiochemical factors, such as the surface reactive characteristics of milled fibers, may be more closely related to CL production by PMN.
Main purpose of our study was to examine whether painters with long-term exposure to mixtures of organic solvents show slight dysfunctions in color vision ability. The study population consisted of 140 men with chronic exposure to organic solvents from paint and thinners (mean duration of exposure: 26 years). We used the Lanthony Desaturated Panel-D-15 (LDP-D15) to test color vision and calculated the color confusion index (CCI). The results were compared with reference values taken from the literature. Additionally the questionnaire Q18 for solvent related neurotoxic symptoms was applied and its results compared with the CCI. Painters between 25 to 55 years old had higher median CCI values than the respective age group of the references. No statistical significant association between CCI and the actual or chronic solvent exposure was found. The results of the Q18 did also not correlate significantly with the exposure indices. We recommend further studies to explore if the color confusion index is an appropriate indicator of early neurotoxic effects in painters.
A 70-year-old man developed a slowly progressive cerebellar syndrome after having been exposed to carbon disulfide (CS2) in a viscose rayon plant for 27 years. Ataxia, dysmetria, dysarthria and adiadochokinesia appeared 7 years after retirement from work (at age 54), and were later accompanied by cognitive deterioration, dysmnesia, spatio-temporal disorientation, emotional lability, and paranoid-obsessive disturbances. Brain computed tomography (CT) and magnetic resonance imaging (MRI) showed advanced global cerebellar atrophy, and a picture of less severe cerebrocortical atrophy. The case illustrates the possibility of chronic toxic encephalopathy among patients with previous long-term exposure to CS2. In such instances, cerebellar damage may develop as an exceptional, delayed manifestation of neurotoxicity: brain imaging techniques can significantly contribute to the diagnosis and follow-up, in addition to occupational anamnesis and neuropsychiatric evaluation. The patient presented also serves as a remainder that neurodegenerative disorders of apparently unknown origin sometimes derive from occupational toxic exposures suffered in the past.The clinical manifestations may appear several years after retirement from work, when the effects of toxic damage combine with age-related neuronal loss to overcome the brain functional reserve.
An invited report on national occupational health research priorities, agenda and strategy of Japan was delivered in the NORA (National Occupational Research Agenda) Symposium 2001, USA. The third NORA Symposium was held by the US National Institute for Occupational Safety and Health (NIOSH) in Washington DC on June 27, 2001. The national conference in Japan entitled “Conference on Occupational Health Research Strategies in the 21st Century” was organized by the Japanese Ministry of Labour (Currently, Ministry of Health, Labour and Welfare) in the years 1998-2001, and the national occupational health research agenda and strategy for the next decade in Japan was identified. A total of 50 Conference members, i.e., representatives from various fields of occupational health in Japan, ranked 58 comprehensive research topics, yielding short-term (5-year) and long-term (6-10 year) priority research topics. Overall (10-year) priority research topics were calculated by combining the short-term and long-term priority scores. Together with the ranking by 145 extramural occupational health specialists, it was identified that work stress (i.e., one of the 58 research topics) was the first overall priority research topic for the next 10 years in Japan. Three other topics, i.e., elderly workers, women workers and maternity protection, and mental health and quality of work and life, were the second group of priority topics; and hazard and risk assessment and biological effect index were the third priority group. Based on the scores for the short-term and long-term priority research topics, all 58 research topics were classified into three key research areas with 18 key research issues (National Occupational Health Research Agenda, NOHRA). Finally, eight implementation measures of national strategy for the Japanese Government to promote occupational health research were introduced.