The developmental effects of dioxin are important because of the high sensitivity of mammals as well as the irreversibility and longevity of the effects. In animal experiments, exposure to dioxin during pregnancy and lactation induce various functional effects on offspring at very low doses. In humans, even if there is no exposure to dioxin after birth, there might be effects on thyroid function in infants exposed to dioxin from breast milk. In this report, low-dose developmental effects of dioxins on offspring in animal experiments and human studies were reviewed. In terms of risk assessment, methods to describe dosimetry, models to describe dose-response and approaches to express health risk are discussed.
In an electronics plant, 2 one-component epoxy coatings containing a modified polyamine hardener were used as covering materials for protecting important information on police radio circuit boards. The resinous parts of the coatings consisted of epoxy resins based on diglycidyl ether of bisphenol F. The hardener was a dimethylaminopropylamine (DMAPA)-epoxy adduct and contained about 0.16% free DMAPA. Of 105 workers, 17 (16%) were diagnosed to have workrelated dermatitis but were not patch tested. The hands were the commonly affected region (13 out of 17 cases). The latent period of dermatitis was very short (mean 21.5 days). The work-related dermatoses were closely related to the type of work and working periods. In the present study, hand protection and the introduction of automation have been demonstrated to be useful for the prevention of epoxy coating dermatitis.
To determine whether body mass index (BMI, kg/m2) or percentage body fat (%BF) by bioelectrical impedance analysis (BIA) better reflects the cardiovascular risk profile, we examined the associations among BMI, %BF by BIA, and cardiovascular risk factors (systolic blood pressure (SBP), diastolic blood pressure (SBP), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), LDL-C/HDL-C ratio, and triglycerides (TG)) in 1, 217 Japanese male office workers aged 25 to 59 years. From stepwise regression analyses of cardiovascular risk factors on age, BMI, alcohol intake, and cigarette smoking, significant correlates were, in the order of relative importance: age, BMI, and alcohol intake for SBP and DBP (the cumulative percentage of variation; 14.9% and 21.3%, respectively); age, BMI, and alcohol intake (negative) for LDL-C (11.0%); BMI (negative), alcohol, and cigarette smoking (negative) for HDL-C (19.9%); BMI, alcohol intake (negative), age, and cigarette smoking for LDL-C/HDL-C ratio (23.1%); and BMI, age, cigarette smoking, and alcohol intake for Log TG (21.7%). From stepwise regression analyses using %BF by BIA as an independent factor, %BF by BIA was also significantly associated with each cardiovascular risk factor, but the decrease in explained variance for each cardiovascular risk factor was 0.2-4.5%, compared with the model using BMI as an independent factor. These results suggest that BMI may better reflect blood pressure or serum lipid profile than %BF by BIA.
In order to find out the work load of matrons under shift work in a special nursing home for the elderly (SNH), six healthy female matrons volunteered to participate in the present study. For each subject, care working time, heart rate, walking steps, estimated energy expenditure and working time in different postures were determined during day shift work (540 min) and night shift work (960 min). Although the time on duty, working and recess were significantly longer in night shift work than day shift work, the percentages of working and recess time to duty time were nearly the same regardless of shift work. The longest care work in each shift work was individual care of residents in the SNH. The maximum, minimum and mean heart rate and percentages to estimated maximal heart rate were similar in each shift work. Although total walking steps in night shift work were significantly larger than those in day shift work, steps per hour did not differ between them. The estimated total energy expenditure (kcal) was significantly higher in night shift work than in day shift work; however, the work intensity (kcal/kg/min) was significantly higher in day shift work. The longest length and larger percentage of working time were observed in standing posture in each shift work. These findings suggest that physical activity and energy expenditure of matrons under either shift work in the SNH seem to be high. Further studies are needed to clarify the work load of matrons engaged in SNH to formulate countermeasures.
The aims of the present work were to quantify ability to induce lucigenin-dependent chemiluminescence (CL) from 6-9 day-old human monocyte-derived macrophages exposed to various mineral fibers, and to examine the relationship between ability to induce CL and fiber size. All fiber samples induced the CL response from the cells. The relationship between the number of fibers administered and the CL response was examined on all fiber samples by linear regression. The slope of the regression line supplies an approximation of the ability to induce CL. A strong increased correlation between geometric-mean length of fibers and ability to induce CL was observed for the seven fiber samples more than 6 μm in length (r=0.9895). Geometric-mean width and the ability to induce CL showed no correlation. However, among the two fiber samples having a similar length distribution (RF2, RF3), the wider width sample (RF3, 2.4 μm) demonstrated lower ability to induce the CL than the narrower width sample (RF2, 1.1 μm). The present method enabled comparison of ability to induce lucigenin-dependent CL from human monocyte-derived macrophages for various mineral fibers with different sizes. Our findings suggested the possibility that ability to induce O2- production increased with fiber length, when fibers are longer than approximately 6μm.
Object of this preliminary study was the immune response to high or low frequency electromagnetic fields (ELMF) of non-atopic and atopic fertile women with uniform exposure to toxic compounds produced by traffic. Women were divided in group A (non-atopic, non-exposed to ELMF); B (atopic, non-exposed to ELMF); C (non-atopic, exposed to ELMF); D (atopic, exposed to ELMF). “In vitro” cell proliferation of peripheral blood mononuclear cells (PBMC) of atopic women (groups B and D) stimulated by phytohaemoglutinin (PHA) was reduced. The ELMF exposed women (groups C and D) showed lower levels of blood NK CD16+-CD56+ lymphocyte subpopulations and of “in vitro” production of interferon-γ (both spontaneously and in presence of PHA) by PBMC, suggesting that ELMF reduces blood cytotoxic activity. Serum IgE of the atopic women exposed to ELMF (group D) was higher than that of the other groups. Linear discriminant analysis including serum zinc and copper (essential enzymes for immune functions), blood lead and urinary transtrans muconic acid, a metabolite of benzene (markers of exposure to traffic) and key parameters of immune functions (CD16+-CD56+ lymphocyte subset, serum IgE, interferon-γ produced by PBMC in presence of PHA, stimulation index of blastogenesis) showed absence of significant difference between groups A and C and a marked separation of groups B and D. This datum suggests that ELMF have a greater influence on atopic women exposed to traffic than on non-atopic ones.
The Monfalcone area, northeastern Italy, is a small industrial district (population 60, 000), with a large shipyard. In order to monitor asbestos exposure in this area, a series of 3, 640 necropsies, carried out at the Monfalcone Hospital between October 1979 and September 1998, were investigated. The thoracic cavities were examined for pleural plaques; these were classified into three classes (small, moderate, large). Routine histological sections of lung tissue were examined for asbestos bodies. Isolation and counting of asbestos bodies were performed in 1, 075 cases. Lifetime occupational data were collected in 1, 277 cases. Pleural plaques were observed in 70.5% among men and in 23.8% among women. The prevalences of pleural plaques did not show significant variations during the study period. Asbestos bodies were found on routine lung sections in 23.7% of men and 3.0% of women. The shipyard workers, the most numerous category in the series, were characterized by high prevalence of pleural plaques (total 86.7%, large 32.4%), high prevalence of asbestos bodies on routine lung sections (35.3%), and high amounts of lung asbestos bodies after isolation. The present data indicate that asbestos exposure may reach alarming levels in the shipyard areas.
Chronic toxicity and carcinogenicity studies of 3-chloro-2-methylpropene (CMP), which has been widely used as an insecticide and chemical intermediate, were carried out in BDF1 mice. CMP was administered to mice in groups of 50 male and 50 female mice by the inhalation route 5 days per week for 104 weeks at doses of 0, 50, 100 or 200 ppm. Male and female mice in the CMPexposed groups had decreased body weight but no noticeable clinical signs when compared with the control group. Dose-related increases in the incidences of gastric mucosal hyperplasia and squamous cell papilloma were observed in both sexes, and squamous cell carcinoma was observed in only one male mouse in the 100 ppm group. An increased incidence of Harderian gland adenoma in female mice was also recognized. In the nasal cavity, eosinophilic exudate associated with atrophy of olfactory epithelia, respiratory metaplasia of olfactory epithelia and olfactory gland, and eosinophilic changes in respiratory and olfactory epithelia were increased in both sexes.
Ageing is associated with changes in physical characteristics and decline of many physiological functions. It has been accepted that the oxidative stress or damage induced by free radicals is related to ageing. Three age groups, 3, 12 and 24 months, were used to investigate whether age-associated changes in some parameters (vitamin C and ceruloplasmin) in the plasma of male Swiss-Albino rats and to observe possible effects of sulfur dioxide (SO2) for 6 weeks on the same parameters. Rats were exposed to 10 ppm SO2 1 hr/day, 7 days/week for 6 weeks. Control groups were exposed to filtered air in the same conditions. An effect of SO2 on those parameters was observed. The level of vitamin C and ceruloplasmin in plasma were decreased in young, middle-aged and old groups in responce to SO2.
An inhalation exposure system, consisting of an inhalation chamber and an generating and feeding device for welding fumes and gases with a welding robot, was constructed and examined for its application to experimental toxicology for ventilatory responses of conscious rats to welding fumes and gases. The exposure system allowed an inhalation of fresh welding fumes and gases, and could supply airflow containing stable concentrations of fumes and ozone even the levels exceeding those corresponding occupational exposure limit values were supplied into the exposure chamber. The air temperature in the chamber was kept constant under rat's physiological conditions. Rats were exposed to fresh welding fumes and gases and examined for their ventilatory responses with a body plethysmograph in the chamber. A transient increase in breathing frequency with a concomitant decrease in the tidal volume was observed within several minutes immediately after the start of welding operation. The rapid, shallow breathing response disappears after repeated exposures, indicating rapid adaptation of this ventilatory response to inhalation of welding fumes and gases.
Platinosis (severe dermatitis and/or asthma) may be broadly defined as the effects of soluble platinum salts on people exposed to them occupationally. Platinum coordination complexes are widely used in the treatment of a variety of solid tumors. However, the clinical use of cisplatin (the most useful agent) is limited by the development of nephrotoxicity. High dose exposure of soluble platinum could possibly induce nephrotoxicity, occupationally. Urinary citrate is freely filtered at the glomerulus, and its reabsorption in the proximal tubule is the major determinant of rate. In this study, we exposed isolated rat renal brush border membrane vesicles (BBMV) to cisplatin and examined their citrate uptake characteristics. BBMV were prepared by the divalent cation precipitation method. Citrate uptake was measured by the Millipore rapid membrane filtration technique. The preincubation of BBMV with 5 mM of cisplatin for 4 and 8 hours significantly inhibited citrate uptake compared with that of the control BBMV. These findings might contribute to nephrotoxicity in cisplatin therapy.
Although prevention strategies to assure good mental health in the workplace have become important, worker notification in studies using psychometric tests has rarely been discussed. Until now it has been difficult to prepare a large number of notifications that are tailored well for individual workers. We have developed a system to create notifications that explain the results for individual workers in plain language using a relational database (RDB). First, scores for each test were divided into categories and the workers' data was classified. Then, explanations were written for each category. RDB software read component files into a database file, integrated all data, and printed out notifications. After the system was developed, we realized its high potential for use in occupational health care, as well as in many other fields. We also report an example of its application.