A lifestyle to prevent or combat the metabolic syndrome among Japanese workers: analyses using the health belief model and the multidimensional health locus of control.

We investigated the predictors significantly associated with a lifestyle to prevent or combat the metabolic syndrome among Japanese workers. We conducted an anonymous self-administered questionnaire survey and analyzed the resulting data using multiple linear regression analysis. The dependent variable was a lifestyle to prevent or combat the metabolic syndrome (7-point scale). Independent variables were: subjects' basic attributes (age, gender, blue or white collar worker, with or without a family physician), Multidimensional Health Locus of Control (7-point scale for each item), with or without the metabolic syndrome being pointed out or not by healthcare providers, and 4 items regarding the metabolic syndrome produced with reference to the Health Belief Model (7-point scale for each item). Those independent variables were all included in this model. The analysis shows the older workers, white-collar workers, and workers who had the metabolic syndrome pointed out by healthcare providers had appropriate lifestyles. Those with high scores in Powerful Others Health Locus of Control also had appropriate lifestyles. Those who realized that the metabolic syndrome was a life-threatening disease and who knew practical ways to prevent or combat the metabolic syndrome also had appropriate lifestyles. Our findings can be applied to various types of medical education regarding the metabolic syndrome.

Predictors of Japanese workers' motivation to use the results of worksite health checkups in their daily health management.

Japanese law stipulates that workers undergo worksite health checkups. If workers do not use their results of those checkups in their daily health management, the merit of this law will not be realized. Therefore, it is important to identify the predictors to improve their motivation to use the results of health checkups. We investigated those predictors by using a questionnaire survey. Multiple linear regression analysis was conducted for 1,791 subjects (1,530 males and 261 females) at a Japanese manufacturing plant. The average age of enrolled subjects was 42.0 years (standard deviation [S.D.], 13.4 years). The average age of male subjects was 42.3 (S.D., 13.8) years and that of the female subjects was 39.9 (S.D., 10.4) years. The results revealed that as workers advanced in age, they maintained their motivation more to use those results. Women maintained their motivation more than men. Workers who believe that their health depends on the influence from physicians and healthcare providers in hospitals felt motivated. Workers who realized the effectiveness of those checkups to maintain good health, who knew how to adopt an appropriate lifestyle, and who were given consultations with physicians when they received their health checkups, felt motivated. Regarding the healthcare organizations' and occupational health staffs' responsibilities, only detecting illness early is not sufficient. Those healthcare providers must value more primary prevention. Our findings can be applied to various occupational health activities, including health consultations, health education seminars, and providing appropriate instruction on how to interpret the results of the worksite health checkups.

Survey of the degree of examinees' satisfaction with instructions on how to read results of general health checkups at a workplace.

To clarify measures for making clearer instructions on how to read the results of general health checkups in a workplace by surveying the views of workers on these instructions, an anonymous self-administered questionnaire survey was conducted at a Japanese manufacturing plant. The responses of 984 male workers were analyzed. The average age of the subjects was 32.1 yr (range, 19-60 yr). Regarding the instructions, 4.1% of the subjects answered "definitely sufficient," 58.9% "somewhat sufficient," 28.0% "neither sufficient nor insufficient," 8.1% "somewhat insufficient" and 0.8% "definitely insufficient." Multiple regression analysis showed that the degree of examinees' satisfaction significantly correlated with the health condition (standard partial regression coefficient =0.189, p<0.001), knowledge of health management (standard partial regression coefficient =0.095, p=0.014), and fear of lifestyle-related diseases (standard partial regression coefficient =0.095, p=0.009). The adjusted R square value of the multiple regression analysis was 0.064. It is necessary to provide more detailed information to those with poor health. Because the instructions contain many difficult medical terms, health professionals must give instructions that are easy to understand. Those feeling fear of lifestyle-related diseases may already know how to read checkup results. It is necessary to promote awareness of lifestyle-related diseases targeting people unfamiliar with such diseases.

Comparative cytotoxicity study of rock wool and chrysotile by cell magnetometric evaluation.

Rock wool (RW), a type of man-made mineral fiber (MMMF), is a building material used as an asbestos substitute for heat insulation, fire resistance, and reinforcement. RW is included in group 3 of the IARC classification. In the present study, the cytotoxicity of RW was investigated by cell magnetometry, enzyme assay, DNA ladder detection, and electron microscopic morphological evaluation in comparison with chrysotile fibers (CF). Specimens were prepared by 18-h incubation of Fischer rat alveolar macrophages in the presence of RW fibers as the study material, CF as positive control, and phosphate-buffered saline (PBS) as negative control, together with a relaxation indicator, Fe3O4, except for morphological evaluation, followed by additional procedures of external magnetization and subsequent 20-min remanent magnetic field measurement for magnetometric evaluation, and macrophage DNA extraction for evaluating possible apoptosis by DNA ladder detection. In magnetometry, relaxation, a marker of cytotoxicity, was rapid in both the RW- and PBS-treated groups, while it was delayed in both the long and short CF-treated groups. Differences in percent lactate dehydrogenase (LDH) release between the RW-treated group and PBS-treated group were not significant, but those between the RW-treated group and short CF-treated group were statistically significant. A DNA ladder was not detected in any of the study groups. Electron micrographs showed that RW did not cause any change, but CF caused changes in macrophages. Thus, magnetometric measurements suggested no cytotoxicity of RW. We plan, in the future, to evaluate the safety of RW by magnetometric measurement and morphological observation of the lungs in in vivo inhalation experiments.

Magnetometric evaluation of cadmium oxide-induced toxicity to pulmonary alveolar macrophages of Syrian golden hamsters.

Since alveolar macrophages play an important role in the clearance of inhaled dust from air-ways, these cells have been used as a target for various toxic chemicals. Alveolar macrophages obtained from bronchoalveolar lavage of Syrian golden hamsters were concurrently exposed in vitro to Fe(3)O(4), as an indicator for magnetometry, and various concentrations of cadmium oxide (CdO) in this study. A rapid decrease of the remnant magnetic field, called relaxation, was observed after the cessation of an external magnetic field stimulus in macrophages concurrently exposed to phosphate-buffered saline or CdO at 0.1 microg/ml, while relaxation was delayed in those concurrently exposed to 1, 25, or 50 microg/ml CdO. Therefore, the concentration of CdO affecting relaxation in vitro was estimated at between 0.1 and 1 microg/ml. Release of LDH activity from CdO-exposed macrophages into the medium significantly increased at levels of 25 and 50 microg/ml CdO. Apoptosis was not detected in macrophages exposed to CdO by the DNA ladder detection method or morphological observations. Electron-microscopic examination revealed severe membrane damage and vacuolar changes in macrophages exposed to CdO. Since delayed relaxation is thought to occur by (1). disrupted cytoskeleton-driven random rotation of phagosomes containing iron oxide particles, (2). significant lactate dehydrogenase (LDH) activity release, and (3). detachment of cell membranes, CdO is considered to affect macrophage functions.

In vitro toxicity of indium arsenide to alveolar macrophages evaluated by magnetometry, cytochemistry and morphological analysis.

The present study was conducted to clarify the toxicity of Indium arsenide (InAs) particles to alveolar macrophages of hamsters by cytomagnetometry, enzyme release assays and morphological examinations. One million alveolar macrophages obtained from hamsters were exposed to 60 microg of ferrosoferric oxide and 2, 4, 10 and 20 microg of InAs particles. Relaxation, which is the rapid decline of strength of the remanent magnetic fields radiating from the alveolar macrophages, was insignificantly delayed and decay constants were not changed due to exposure to such doses of InAs. Because the relaxation is thought to be associated with the cytoskeleton, the exposure to InAs may not have impaired their motor function. An LDH release assay and morphological findings indicate slight damage to macrophages. DNA electrophoresis and the TUNEL method revealed neither necrotic changes nor apoptotic changes. Thus, InAs particles at such doses hardly cause cytostructural changes and cell death.

Differences in the effects of fibrous and particulate titanium dioxide on alveolar macrophages of Fischer 344 rats.

Alveolar macrophages are considered to play a major role in the pathophysiology of lung diseases caused by exposure to various kinds of pathogens and particles. In this study, the cytotoxic effect of different shapes of titanium dioxide (TiO(2)) was evaluated on macrophages using a unique magnetometry method and was compared with conventional methods of lactate dehydrogenase (LDH) release, apoptosis measurement, and morphological observations. Alveolar macrophages obtained from Fischer rats (F344) by bronchoalveolar lavage were incubated in vitro for 18 h with Fe(3)O(4) as a magnetometric indicator and fibrous and particulate forms of TiO(2) as test materials. In the control and particulate exposed group, rapid attenuation of the residual magnetic field, so-called "relaxation," was observed immediately after cessation of the external magnetic field. In comparison, a delay of relaxation was observed in alveolar macrophages exposed to fibrous TiO(2). LDH released into serum-free medium induced by exposure to TiO(2) increased significantly in a concentration-dependent manner in macrophages exposed to fibrous TiO(2), while negligible LDH release was observed in macrophages exposed to particulate TiO(2). The DNA ladder detection method and morphological examination detected no apoptosis in macrophages exposed to 60 micro g/ml of fibrous or particulate TiO(2). Electron microscopic examination revealed vacuolar changes and cell surface damage in macrophages exposed to fibrous TiO(2), but no significant changes in macrophages exposed to particulate TiO(2). The results of magnetometry, LDH release, and electron microscopy suggest that cytotoxicity of TiO(2) depends on the shape of the material.

Negative effect of photocopier toner on alveolar macrophages determined by in vitro magnetometric evaluation.

Photocopier toner has been implicated in the etiology of some pulmonary diseases. We examined here the in vitro toxicity of toner particles to alveolar macrophages. Cell magnetometry revealed that relaxation was not delayed in macrophages exposed to toner, which represents a rapid decrease in the remaining magnetism emitted by phagocytosed magnetite. However, relaxation was delayed in macrophages exposed to silica (positive controls). The release of intracellular LDH enzyme activity to the extracellular space was negligible in cells exposed to toner compared with negative and positive controls. Morphological examinations by light and electron microscopy revealed no abnormal findings in the exposed cells. A histochemical study using TUNEL staining and the electrophoretic profile of DNA obtained from cells exposed to toner and to silica were negative for apoptosis. The results of the present and other investigations into animal exposure indicate that photocopier toner is toxicologically inert. However, although the present study examined only effects in vitro, exposure to toner should be minimized because lung overloading in animals has been reported.