Asbestos has been an indispensable insulating material for railway industries, especially steam locomotives (SLs). This review (1928-1987) consists of three parts. 1) Pleural plaques: Since the 1970s, pleural plaques have been regarded as evidence of past asbestos inhalation, and more recently recognized as a risk factor of asbestos-related malignancies. For diagnostic criteria on plain radiographs, the modified ILO 1980 International Classification of Radiographs of Pneumoconioses was used. Most cases had pleural plaques with normal lungs. Large plant workers showed a significantly higher rate of plaques than workers in smaller plants. Bilateral plaques were dominant followed by the left, then the right lung, and chest wall plaques were dominant over the diaphragm. The manifestation of pleural plaques was more correlated to years since the onset of the asbestos exposure than the sum of asbestos work years, although the result was not significant. The boilermen of railway ferry steamers had a significantly higher plaque rate than other seamen. CT studies on plaques started in 1978. 2) Asbestos-related malignancies: Five retrospective cohort studies 1960-1970 were made on primary lung cancer incidence and mortality among 350,000 active railway men with smoking information. The follow-up period was 20 yr at the longest. Almost all plant workers showed a tendency of higher incidence or mortality than the controls. Two cases of mesothelioma were reported in 1980. 3) Pneumoconioses: Most studies (1928-1975) had relatively low prevalence rates among SL-related workers.
Objectives are to investigate the effects of benzo[a]pyrene (B[a]P) on the autonomic nervous system of coke oven workers. One hundred eighty-four coke oven workers were divided into 3 groups according to their working sites (coke oven bottom group, coke oven side group and coke oven top group), and 93 referents were recruited. B[a]P monitored by air sampling pumps as well as urinary 1-hydroxypyrene (1-OH-Py) was determined by high performance liquid chromatograph with a fluorescence detector (HPLC-FD). The autonomic nervous system (ANS) function was determined by 4 tests: Valsalva Manoeuvre heart rate variation (HR-V), variation of heart rate when breathing deeply (HR-DB), variation of heart rate when instantly standing up (HR-IS, including RR30:15 and RRmax:min) and variation of blood pressure when instantly standing up (BP-IS). The B[a]P mean concentrations in coke oven bottom, coke oven side and coke oven top were 19, 185 and 1,623 ng/m3, respectively. The levels of urinary 1-OH-Py were markedly higher in the 3 exposed groups than that in the referent group (p<0.01). No significant difference was found in each group between smokers and non-smokers (p>0.05). Compared with referents, HR-V decreased significantly in coke oven workers (p<0.01), representing modulation of parasympathetic nervous function. However, no statistical differences were found in HR-DB, RR30:15, RRmax:min and BP-IS between the exposed groups and the control group (p>0.05). HR-V decreased with the increment of 1-OH-Py (p<0.05), and results of multiple linear stepwise regression demonstrated that external exposure level and duration of education entered the HR-V model; age was a significant factor of HR-DB and RRmax:min, but no variable was involved in RR30:15 and BP-IS regression. Benzo[a]pyrene affects the autonomic nervous function of coke oven workers mainly by down-regulating the parasympathetic nervous function.
Since the Family Policy Act, which requires companies to develop action plans to support their employees who have children in an attempt to reverse the declining birthrate in Japan, was enacted in 2003, many Japanese organizations and occupational health staff have become interested in work-family conflict (WFC), especially WFC in employees with young children. A cross-sectional survey of regularly employed information technology (IT) engineers with preschool children in Japan was conducted to examine the gender difference in WFC, relationship of WFC with outcomes, and predictors of WFC by gender. Data from 78 male and 102 female respondents were analyzed. There was no significant gender difference in total level of WFC. However, the level of work interference with family (WIF) was significantly higher in males than in females and the level of family interference with work (FIW) was significantly higher in females. Regarding outcomes, WIF was significantly related to depression and fatigue in both genders. Moreover, different predictors were related to WIF and FIW by gender. A family-friendly culture in the company was related to WIF only in males. To prevent depression and cumulative fatigue in employees with young children, occupational practitioners have to pay attention to not only employees' work stress but also their family stress or amount of family role in both genders.
Idiosyncratic generalized skin disorders complicated by hepatitis, which resemble severe drug hypersensitivities, occur sporadically in workers exposed to trichloroethylene (TCE) in China. However, it has been a matter of controversy whether the solvent itself, not its impurities or stabilizers, can cause hypersensitivity reactions or not. This study aimed to characterize the exposure of hospitalized patients and their healthy colleagues. TCE metabolites were measured in urine of 19 hospitalized patients suffering from the disorders. To assess the exposure of patients' healthy colleagues, on-site surveys were conducted in 6 factories where the disorders occurred and in 2 control factories without such occurrences despite TCE use. Urinalysis of the patients detected trichloroacetic acid (TCA) in all of them. Its average concentration in the end-of-shift urine was estimated to be 206 mg/l. On-site survey of healthy exposed workers revealed that the maximum urinary TCA concentrations and the maximum time-weighted average concentrations of personal TCE exposure were 318-1,617 mg/l and 164-2,330 mg/m3, respectively. There was no common impurity in TCE used in the factories. These results suggested that TCE itself caused the skin hypersensitivity disorders, and that the disorders occurred in factories where TCE metabolites could be extensively accumulated, possibly due to long working hours. Since the lowest TCA concentration in the end-of-shift urine of the patients was estimated to be 72-80 mg/l, it is recommended to control TCE exposure to keep the urinary TCA concentration below 50 mg/l to reduce the disease risk.
Cadmium fluoride (CdF2, CdF for short) is the most lethal and hepatotoxic of all Cd-containing compounds. The toxic effects of CdF appear to depend on its detoxification and elimination. This study was designed to determine the early dynamics of the absorption, systemic distribution, and metabolism of CdF. The kinetics of cadmium and fluoride were investigated in the blood, bile, and urine of rats as a model of accidental occupational exposure to CdF. The serum concentration-time profiles measured after intravenous CdF (1.34, 2.67 or 4.01 mg/ per kg body weight) administration were analyzed by compartmental modeling using the WinNonlin program. Bile and urine were collected for 300 min after the administration. The kinetic profiles indicate that the clearance of Cd was diminished in the 2.67 and 4.01 mg/kg groups, leading to a persistently high serum Cd level. The mean total biliary excretions of Cd in the 2.67 and 4.01 mg/kg groups were significantly higher than that in the 1.34 mg/kg group. The abnormal kinetics of Cd was attributable to severe hepatic injury that diminished the capacity for Cd accumulation. The elimination of serum F was delayed in the 4.01 mg/kg group. The mean urinary F excretion amount was not significantly higher in the 4.01 mg/kg group than in the 2.67 mg/kg group. The abnormal kinetics of F was attributable to nephrotoxicity that diminished its elimination from the kidney.
Marital status is related to cardiovascular disease (CVD) risk factors in Western countries. However, few studies have addressed the relationship between marital status and CVD risk factors in other populations. We investigated lifestyle and CVD risk factors relative to marital status among middle-aged Japanese men. We analyzed baseline data of 40-59-yr-old male workers who participated in the high-risk and population strategy for occupational health promotion (HIPOP-OHP) study. We compared lifestyle and CVD risk factors between men who were married (Group M; n=1,419, mean age 47.9 ± 5.1 yr) and those who had never married (Group N; n=163, mean age 46.7 ± 4.3 yr). Men in Group N were more likely to skip breakfast, work more shifts and exercise less. Current smoking rates, as well as average values of diastolic blood pressure (DBP), serum total cholesterol and fasting plasma glucose were also higher in Group N than in Group M. The proportion of participants with three or more CVD risk factors, namely smoking, hypertension, hypercholesterolemia and hyperglycemia was higher in Group N, than in Group M (12.9% vs. 5.0%, p<0.01). The difference between Groups M and N was more evident in the subgroup of living with others, than in the subgroup of living alone. Since men who have never married might be at higher risk for CVD, effort should be made to educate this population about decreasing lifestyle-related risk factors.
Healthcare workers are at high risk of being victim of verbal and physical violence perpetrated by patients. There are only a few studies on work related violence among physicians. The aim of this study was to determine how prevalent work-related violence against physicians is and whether gender, age, specializations and workplaces are associated with verbal and physical violence against physicians in Japan. A questionnaire was mailed to all the 1,705 physicians who had graduated from one medical school in Japan and had practiced for a minimum of 3 yr by the time of this study. The verbal and physical violence experienced by physicians at the hands of their patients and/or clients in the last 6 months preceding this study were collected. We defined `verbal violence' as `any threatening statement or complaint' while `physical violence' referred to `the attempted or actual exercise by persons of any physical force so as to cause injury to a physician'. Multiple logistic regression analysis was used to determine the independent contribution of each factor with violence. A total of 540 men and 158 women responded. The adjusted response rate was 41.8%. Among the participants, 168 (24.1%) physicians had experienced verbal violence and 15 (2.1%) physicians had experienced physical violence in the prior 6 months. Verbal violence was positively associated with physicians who were under 30 yr old (odds ratio [OR] = 2.1; 95% confidence interval [CI], 1.0-4.1 for 27-29 yr old) and, psychiatry (OR, 2.4; 95% CI, 1.1-5.4). Physical violence was significantly associated with women (OR, 3.8; 95% CI, 1.1-13.5), specializations such as emergency and anesthesiology (OR, 18.9; 95% CI, 2.8-126.1), and psychiatry (OR, 7.6; 95% CI, 1.6-35.4). There was a considerable number of physicians exposed to violence. Younger physicians and psychiatrists are likely to be exposed to verbal violence. Female physicians, psychiatrists, and emergency physicians are likely to be exposed to physical violence. Education on avoiding from violence should be provided for physicians early in their career.
We examined the stabilities of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) stored at room temperature (25°C) for 24 h or at -80°C for 800 days. Subjects were 19 males and 17 females aged 23-58 yr for the 24-h study, and 9 males and 4 females aged 24-54 yr for the 800-day study. We obtained information on the subjects by questionnaires and interviews. The level of urinary 8-OHdG was measured by HPLC using two-step separations. There were no significant changes of amount of urinary 8-OHdG under either storage conditions. We conclude that urine samples can be stored at 25°C and below for 24 h, when the research purpose includes the determination of urinary 8-OHdG. Urinary 8-OHdG was also stable for over two years when stored at -80°C.