The degree of workers' use of annual health checkup results among Japanese workers.

In Japan, the Industrial Safety and Health Law obliges all workers to undergo annual health checkups in their workplaces. At the plant for this study, workers who have one or more abnormal findings pointed out in their annual health checkups are summoned by occupational health staff and subsequently attend health consultations conducted by occupational health nurses each year. We investigated what kinds of health consultations have improved the workers' use of the results of their annual health checkups by an anonymous self-administered questionnaire survey. In addition, we discussed the associations with the multidimensional health locus of control (MHLC) and the degree of the workers' use of these results. A total of 837 questionnaires were analyzed. The average age of the respondents was 47.9 yr (range: 19-68 yr). The main results suggest that it is necessary for occupational health staff to give workers practical advice to improve their lifestyle habits and convey to them the effectiveness of preventive health behaviors. Workers with high scores in the belief in the "internal health locus of control (IHLC)" and low scores in the "chance health locus of control (CHLC)" use the results of their health checkups to help them manage their own health.

A pilot study testing the dimensions of safety climate among Japanese nurses.

To investigate the dimensions of safety climate among Japanese nurses, an anonymous self-administered questionnaire survey was conducted. The subjects involved in the survey included 293 full-time nurses (registered nurses and licensed practical nurses) working in a public hospital, excluding directors of nursing. A total of 221 of the 293 nurses answered the questionnaires. Among 221 questionnaires, the questionnaires, which had missing values in the question items used in this study, were excluded from the analyses. Consequently, a total of 201 questionnaires were analyzed. The average age of the subjects was 34.7 yr. As a result of exploratory factor analysis, 5 factors were extracted as follows: intellectual development regarding medical safety among nurses, accumulated fatigue, nursing conditions, supervisors' attitudes, and communication with physicians. All the values of Cronback's coefficient alpha among these 5 factors were between 0.804 and 0.892. As a result of the confirmatory factor analysis of the 5 factors, the value of the GFI (Goodness of Fit Index) was 0.868. The value of the CFI (Comparative Fit Index) was 0.943. The value of the RMSEA (Root Mean Square Error of Approximation) was 0.062. The results of this study will contribute to the investigation of the dimensions of a nurses' safety climate scale in the future. The associations between the dimensions of the safety climate and the motivation to work toward improving patients' safety among Japanese nurses will need to be examined, as will those between the dimensions of the safety climate and actual clinical mistakes.

Factors associated with workers' perceived helpfulness of and need for health consultations given by an occupational physician at a Japanese manufacturing plant.

OBJECTIVE: The aim of this study was to clarify measures for improving the functionality of health consultations by occupational physicians, by examining factors associated with workers' perceived helpfulness of, and need for, these consultations. METHODS: An anonymous self-administered questionnaire survey was conducted at a Japanese manufacturing plant. RESULTS: Multiple regression analyses showed that workers' perceived helpfulness of, and need for, health consultations given by an occupational physician was held in common and significantly associated with the occupational physician's dedication and complete protection of privacy. CONCLUSIONS: For health consultations given by occupational physicians to be effective, it is necessary to help employees realize the physicians' outstanding dedication and to convey to the workers the absolute assurance of their privacy protection.

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.

The association of needlestick injury with depressive symptoms among first-year medical residents in Japan.

Depressive symptoms among medical residents are common. The objective of this study was to determine the association of depressive symptoms with needlestick injury among first-year medical residents (so-called "intern"). We conducted a prospective cohort study among 107 medical residents in 14 training hospitals. The baseline survey was conducted in August 2005 and the follow-up survey was conducted in March 2006. Depressive symptoms were based on the Center for Epidemiological Study of Depression. Factors associated with depressive symptoms were examined using logistic regression analysis. For medical residents without depressive symptoms at the baseline survey, needlestick injury events were associated with depressive symptoms at the follow-up survey (corrected odds ratio [cOR]=2.98; 95% confidence interval [CI], 1.16-3.70). Because it was not possible to determine when the medical residents developed depressive symptoms, it is not possible to definitely determine causality between needlestick injury and depressive symptoms, although these findings are suggestive. Therefore, it would seem prudent to suggest the provision of mental health services to medical residents sustaining a needlestick injury since this may be helpful in identifying and treating depression.

Association between intention to stay on the job and job satisfaction among Japanese nurses in small and medium-sized private hospitals.

In order to examine the relationship between the intention to stay on the job and job satisfaction among Japanese nurses, and to obtain clues for preventing turnover, we conducted a questionnaire survey. The subjects involved in the survey included 625 female nurses (registered nurses, licensed practical nurses and assistant nurses) working in 4 small and medium-sized private hospitals, excluding directors of nursing. Of the 625 questionnaires distributed, 556 (89.0%) were returned. After excluding the questionnaires with missing values, 480 questionnaires were analyzed (effective response rate, 76.8%). The average age of the respondents was 32.8 yr (range: 20-65). The content of the questionnaire was nurse attributes, job satisfaction (30 items) and intention to stay on the job. For job satisfaction, factor analysis (principal factor method and promax rotation) was performed, and factors with an eigenvalue of > or =1 were extracted. Six factors were extracted by factor analysis. These factors were interpreted as "Work as specialists" (1st factor), "Relationship with superiors" (2nd factor), "Comfortable life" (3rd factor), "Relationship among nurses" (4th factor), "Communication with physicians" (5th factor) and "Working conditions" (6th factor). The factor scores were calculated and used as a scale for the evaluation of job satisfaction. To investigate the factors associated with intention to stay on the job among nurses, the standard partial regression coefficient was computed by multiple linear regression analysis, with intention to stay on the job as the dependent variable, and nurse attributes and job satisfaction (factor scores) as independent variables. Various factors including the organizational culture of each hospital may affect the relationship between job satisfaction and the intention to stay on the job. In order to adjust for these factors, differences among hospitals were included in the statistical model as independent variables. The result of the multiple regression analysis suggests that the intention to stay on the job was higher among nurses who were older and more satisfied with work as specialists (1st factor) and working conditions (6th factor).

The cytotoxicity of microglass fibers on alveolar macrophages of fischer 344 rats evaluated by cell magnetometry, cytochemisry and morphology.

OBJECTIVES: The toxicity of microglass fibers (MG), one of the man-made mineral fibers, has not been sufficiently evaluated. The aim of the current study was to evaluate the cytotoxicity of MGin vitro. METHODS: Alveolar macrophages were obtained from the bronchoalveolar lavage of male F344/N rats. The macrophages were exposed to MG at concentrations of 0, 40, 80, 160 and 320 µg/ml. The effects of MG on the macrophages were examined by cell magnetometry, LDH assay and morphological observation. RESULTS: In the cell magnetometry experiment, a significant delay of relaxation (the reduction of remanent magnetic field strength) was observed in the cells treated with 160 and 320 µg/ml of MG in a dose-dependent manner. A significant increase in LDH release was also observed in the cells with 160 and 320 µg/ml in a dose-dependent manner. Changes in the cytoskeleton were observed after exposure to MG by immunofluorescent microscopy using an α-tubulin antibody. CONCLUSIONS: The cytotoxicity of MG on alveolar macrophages was demonstrated with cell magnetometry. The mechanism of the toxic effects of MG was related to cytoskeleton damage.

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.

Multiple chemical sensitivity and idiopathic environmental intolerance (part one).

Multiple chemical sensitivity/idiopathic environmental intolerance (MCS/IEI) is a commonly used diagnostic term for a group of symptoms. These symptoms have been described and commented on for more than 15 years in the USA. Recently, it has also been observed in Japan. The main features of this syndrome are multiple symptoms involving in multiple organ systems that are precipitated by a variety of chemical substances with relapses and exacerbation under certain conditions when exposed to very low levels which do not affect the population at large. There are no laboratory markers or specific investigative findings. Although traditional medical organizations have not agreed on a definition for this syndrome due to the lack of obvious evidence to demonstrate the existence of these symptoms, it is being increasingly recognized. It constitutes an increasing percentage of the caseload at occupational/environmental medical clinics.Part one of this review article discusses pathophysiological theories, substances which cause symptoms, prevalence in the general and specific populations, past history and family history, and clinical symptoms of MCS/IEI patients.

Multiple chemical sensitivity and idiopathic environmental intolerance (part two).

Multiple chemical sensitivity/idiopathic environmental intolerance (MCS/IEI) is a commonly used diagnostic term for a group of symptoms without apparent organic basis. The symptoms are characteristic of dysfunction in multiple organ systems. They wax and wane fluctuate according to exposure to low levels of chemical agents in the patient's environment, and sometimes begin after a distinct environmental change or injury such an industrial accident or chemical introduced after remodeling. Although traditional medical organizations have not agreed on a definition for this syndrome, it is being increasingly recognized and makes up an increasing percentage of the caseload at occupational/environmental medical clinics.Part two of this review article discusses diagnosis, clinical examination, long-term follow up of MCS/IEI, and the role of physicians, research on odor and treatment, diseases with similar symptoms, and further research regarding MCS/IEI patients.

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.