Determination of dimethyl sulfoxide and dimethyl sulfone in urine by gas chromatography-mass spectrometry after preparation using 2,2-dimethoxypropane.

A method for routinely determination of dimethyl sulfoxide (DMSO) and dimethyl sulfone (DMSO(2)) in human urine was developed using gas chromatography-mass spectrometry. The urine sample was treated with 2,2-dimethoxypropane (DMP) and hydrochloric acid for efficient removal of water, which causes degradation of the vacuum level in mass spectrometer and shortens the life-time of the column. Experimental DMP reaction parameters, such as hydrochloric acid concentration, DMP-urine ratio, reaction temperature and reaction time, were optimized for urine. Hexadeuterated DMSO was used as an internal standard. The recoveries of DMSO and DMSO(2) from urine were 97-104 and 98-116%, respectively. The calibration curves showed linearity in the range of 0.15-54.45 mg/L for DMSO and 0.19-50.10 mg/L for DMSO(2). The limits of detection of DMSO and DMSO(2) were 0.04 and 0.06 mg/L, respectively. The relative standard deviations of intra-day and inter-day were 0.2-3.4% for DMSO and 0.4-2.4% for DMSO(2). The proposed method may be useful for the biological monitoring of workers exposed to DMSO in their occupational environment.

Limitations on work and attendance rates after employees with cancer returned to work at a single manufacturing company in Japan.

OBJECTIVES: The purpose of this study was to evaluate the work limitations and attendance rates after employees diagnosed with cancer returned to work from sick leave, and to identify the related factors for the limitations and attendance rates at a single manufacturing company in Japan. METHODS: This study retrospectively analyzed 129 men and 4 women, employed in a single manufacturing industry, who returned to work after sick leave due to newly diagnosis of cancer. Limitations on work after the return to work were enforced in the workplace based on an industrial physician's evaluation. All the employees who needed measures for work were examined by the industrial physicians every 1-6 months until the termination of such work limitations. RESULTS: Limitations on work after the return to work were enforced for 79 (59%) employees (36 employees with alteration of work, 31 with prohibition of shift work and 55 with prohibition of overtime work). A higher degree of work limitations was significantly correlated with work-related factors before sick leave (i.e. shift work, production line) as well as disease/treatment-related factors (i.e. chemotherapy, recurrence/metastasis), while the attendance rates after the return to work were not correlated with adverse work-related factors before sick leave. CONCLUSION: The enforcement of work limitations for employees with cancer was relatively common and was based on both disease/treatment- and work-related factors, and this phenomenon may play an important role in the return to work as well as the successful continuation of work after cancer survivors return to work.

Hazardous environmental factors enhance impairment of liver function in HBV and HCV hepatitis.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) often cause chronic liver disease. We hypothesized that environmental factors adversely impact the liver function in workers with these types of hepatitis. We used liver function tests including aspartate aminotransferase, alanine aminotransferase, and g -glutamyltransferase to evaluate whether hazardous work conditions increase the incidence of chronic liver disease among HBV and HCV infected workers. Organic solvent, night work, visual display terminals, dust, lead, vibrations, and ionizing radiation all led to increased impairment of liver function in patients with hepatitis as compared to the control group that were not exposed to such agents. Therefore, hazardous working conditions have to be carefully considered in the progress of chronic liver disease in workers infected with HBV and HCV.

The effect of smoking prevalence at worksites on individual cessation behavior.

OBJECTIVES: To identify the effect of worksite smoking prevalence on individual cessation behavior. METHODS: We conducted a cohort study at a Japanese worksite without a total ban on smoking, but with designated smoking areas. Baseline data were obtained in 2005 through a self-administered questionnaire from 15,229 workers in 322 work units as part of annual health checkups, and followed up in 2006. Data on smoking status, time to first cigarette after waking up, desire to quit, number of cigarettes smoked per day, and respiratory symptoms were obtained. Details like workers' demographics, blue/white-collar workers, night shift duties, administrative position, and work unit codes were obtained from the firm's administrative records. Smoking prevalence in work units was calculated as a ratio, standardized by age, and categorized into quartiles. Multiple logistic regression was used to predict cessation by smoking prevalence, adjusting for individual level variables. RESULTS: In the lowest smoking prevalence quartile compared with the highest, odds ratios (95% CI) of cessation among those who smoked their first cigarette more than 30 min after waking up were 2.32 (1.06, 5.09) in white-collar units and 1.86 (0.98, 3.55) in blue-collar units, and that among those with a moderate desire to quit was 2.05 (0.94, 4.49) in white-collar units. CONCLUSION: Worksite smoking prevalence affects the likelihood of successful cessation, especially among those with less nicotine dependence and who are in the early stage of behavioral change. This suggests that serious consideration should be placed not only on individual behavior modification but also on modification of worksite conditions.

Methods and rationale for keeping records of hepatitis virus testing in Japanese workplaces.

In Japan, the Ministry of Health, Labour and Welfare issued corporate guidance that employers should recommend their employees to have tests for hepatitis B virus and hepatitis C virus (HV) at least once in their lifetime. However, employers should treat this information as confidential, even though the testing is carried out along with the health examination designated by the Industrial Safety and Health Law. Therefore, the records of HV tests should not be kept by employers, even though records of medical examinations designated by the law must be. This study aimed to clarify the present method for keeping records of HV infection and the rationale in Japanese workplaces. Questionnaires about viral hepatitis were sent to 118 occupational health physicians, and 81 physicians from 100 workplaces responded. The HV test for employees was conducted in 58 workplaces (75.8% of large, 60.4% of bigger medium-sized and 16.7% of smaller medium-sized enterprises). These workplaces were the types of industries where the risk of infecting other persons was low. Subjects of the HV tests were workers who were suspected to have hepatitis virus, and workers who were applicants. Occupational health physicians from most workplaces answered that records of medical examinations designated by law and records of HV tests were not kept separately and shouldn't be. The opinion that the two types of records should not be kept separately appeared to be more from the workplaces where employers or health insurance covered the cost of the HV test. In these cases, the purpose of conducting HV tests at the workplaces was thought to be both promoting welfare of employees and occupational considerations for workers. Occupational health physicians from about 60% of workplaces had misgivings about employees who had hepatitis virus being discriminated against at the workplace if the HV test was included with the required medical examination. Among occupational health physicians from workplaces where occupational health professionals were in charge of the records, there was no standardized rationale for keeping records. However, most workplaces took into consideration the workers' privacy by getting employees' consent before divulging information to their employers. This relied not only on the occupational health professional's or health/safety officer's ethics, but also the necessity of reviewing the purpose and methods of keeping records of HV testing of employees, based on official notices or the Act on the Protection of Personal Information.

Associations of excessive sleepiness on duty with sleeping hours and number of days of overnight work among medical residents in Japan.

Despite long-standing concerns regarding the effects of working hours on the performance and health of medical residents, and the patients' safety, prior studies have not shown an association of excessive sleepiness with the number of sleeping hours and days of overnight work among medical residents. In August 2005, a questionnaire was mailed to 227 eligible participants at 16 teaching hospitals. The total number of sleeping hours in the last 30 d was estimated from the average number of sleeping hours during regular days and during days with overnight work, and the number of days of overnight work. Multiple logistic regression analysis was used to adjust for potentially associated variables. A total of 149 men and 47 women participated in this study. The participation rate was 86.3%. Among the participants, 55 (28.1%) suffered from excessive sleepiness. Excessive sleepiness was associated with sleeping for less than 150 h in the last 30 d (corrected odds ratio [cOR]=1.57; 95% confidence interval [CI], 1.02-2.16). The number of days of overnight work in the last 30 d showed no association with excessive sleepiness. Excessive sleepiness was also associated with smoking (cOR, 1.65; 95%CI, 1.01-2.32). Medical residents who slept for less than 150 h in the last 30 d and smoked had a significantly higher risk of excessive sleepiness on duty.

[International comparison of sensitizing chemical substances].

Some occupational and environmental chemicals cause allergic diseases. To prevent chemical allergies, it is essential to identify the chemical substances that cause sensitization and to eliminate such sensitizers from daily life. As an occupational countermeasure, information for evaluating sensitization of chemical substances is needed. The aims of this article are to compare the criteria for sensitizers among national organizations in various countries and international organizations, and to make out a list of these chemical substances. The definition of sensitizing chemicals and the designation of respective sensitizers according to the PRTR law, Japan Society for Occupational Health (JSHO), American Conference of Governmental Industrial Hygienists (ACGIH), European Union (EU), Deutsche Forschungsgemeinshaft (DFG) and Japanese Society of Occupational and Environmental Allergy were studied. There are 1,389 chemical substances which are designated as sensitizers by any of the laws and five organizations. We specify each chemical substance in the list.

[The effect of chronic health conditions on work performance in Japanese companies].

Chronic disease has a significant impact on workers' productivity. The aim of this study was to determine the prevalence of chronic health conditions, the work impairment score, and the total lost working hours absent at companies in Japan. Eligible participants were all 544 workers of 4 manufacturing companies in the Kanto area. The Stanford Presenteeism Scale that was developed by Merck & Co., Inc and Stanford University was translated into Japanese and was given to the workers at a periodic health examination between April and June 2006. A total of 433 workers completed the questionnaire, and 48.9% of the participants reported having one or more chronic health conditions which affected their work performance. Allergy (13.3%) was the highest primary chronic health condition followed by back/neck disorders (9.7%). The work impairment score was higher for individuals with depression and migraine/chronic headache. The total lost working hours due to the primary chronic health conditions were 1.4% of the total working hours among the participants. The total lost working hours was highest for those with allergy followed by back/neck disorders and depression. These results should make it possible to develop an occupational health program that can reduce the effects of chronic health conditions on work performance.

HBV- and HCV- infected workers in the Japanese workplace.

Around three million Japanese are persistently infected with HBV or HCV. Though most of them work in various industries, little is known about the actual conditions in their workplaces. To clarify the workplace conditions of workers with hepatitis, three kinds of questionnaire surveys, answered by occupational health physicians and workers with hepatitis, were carried out. The rates of workers recognized as workers with hepatitis B or C by occupational health physicians were 0.82% and 0.48% of 130,092 workers, respectively. About 30% of workers with hepatitis were engaged in "hazardous work". The percentage of workers engaged in various types of hazardous work among workers with hepatitis was nearly the same as that among all Japanese workers. About 30% of occupational health physicians witnessed exacerbation of hepatitis in the workers at their workplaces, and 22% of workers with hepatitis experienced exacerbation of hepatitis. The rate of workers with hepatitis who had experienced exacerbation was not significantly different between workers with and without hazardous work. Workers with hepatitis have strong concerns about the relationship between work and exacerbation. As causes of exacerbation, occupational health physicians cited "unknown", "drinking" and "quit treatment" while workers with hepatitis answered "work-related causes", besides "unknown" and "drinking."

Urinary 8-hydoxydeoxyguanosine (8-OHdG) and plasma malondialdehyde (MDA) levels in Aldh2 knock-out mice under acetaldehyde exposure.

To clarify the carcinogenicity of acetaldehyde when associated with ALDH (aldehyde dehydrogenase) 2 polymorphism, Aldh2 knock-out (Aldh2-/-) mice and their wild type (Aldh2+/+) mice were exposed to two different concentrations of acetaldehyde (125 ppm and 500 ppm) for two weeks. Aldh2-/- mice, which have the same genetic background as C57BL/6J (wild mice) except for the Aldh2 gene, were used as models of humans who lack ALDH2 activity. Urinary 8-hydroxydeoxyguanosine (8-OHdG) and plasma malondialdehyde (MDA) levels were measured as indicators of oxidative DNA damage and lipid peroxidation, respectively. At 125 ppm acetaldehyde exposure for 12 d, urinary 8-OHdG levels in Aldh2+/+ mice did not increase. However, urinary 8-OHdG levels in Aldh2-/- mice were slightly increased by the end of the exposure. On the other hand, plasma MDA levels did not increase in either Aldh2-/- orAldh2+/+ mice. At 500 ppm, urinary 8-OHdG levels in both Aldh2-/- and Aldh2+/+ mice significantly increased after 6 and 12 d, but there was no genetic difference. On the other hand, plasma MDA levels in Aldh2+/+ and Aldh2-/- mice did not increase at either 125 ppm or 500 ppm after two weeks of exposure. In conclusion, it is suspected that DNA was damaged by acetaldehyde inhalation, and that susceptibility to acetaldehyde varies according to Aldh2 genotype.

Evidence-based prevention (EBP): A review of cytochrome P450 expression in the bronchial epithelium and new approach to lung cancer prevention.

The number of fatalities in Japan attributable to lung cancer exceeded 50000 in 2001. It is socially desirable that various markers, which can be utilized for the prevention of lung cancer, be established. We believe that smoking or exposure to carcinogens in air induces mutations in bronchial and alveolar epithelia, leading to the development of lung cancer. It would be useful to have markers of individual differences in susceptibility to chemical carcinogen-induced lung cancer 1) to identify genetic polymorphisms of enzymes metabolizing chemical carcinogens and 2) to investigate the expression of enzymes metabolizing chemical carcinogens. In this paper, we review CYP expression in the bronchial epithelium. CYP1, CYP2 and CYP3 are expressed in the bronchial epithelium. We also show the relationship between the genetic polymorphisms of cytochrome P450 (CYP) and a person's susceptibility to chemical carcinogen-induced lung cancer. We demonstrate the relationship between cigarette consumption and the CYP expression profile in the bronchial epithelium. To maintain and promote public health, we must apply evidence, such as CYP polymorphisms and CYP profiles to disease prevention and also to aggressively advance evidence-based prevention (EBP) of lung cancer.