Simultaneous analysis of monosaccharides using ultra high performance liquid chromatography-high resolution mass spectrometry without derivatization for validation of certified reference materials.

Monosaccharide composition of biological samples can reflect an individual's health status. Monitoring the concentration of individual monosaccharides in human serum requires a technique for the simultaneous analysis of multiple monosaccharide molecules. Furthermore, certified reference materials (CRMs) for overall monosaccharide composition of human serum are required in order to validate the performance of clinical laboratory instruments. In the present study, we present a novel method for the simultaneous analysis of numerous monosaccharide molecules without the need for derivatization or post-column treatment. We utilized ultra-high-performance liquid chromatography (UHPLC)-quadrupole/orbitrap mass spectrometry incorporating a hydrophilic interaction chromatography (HILIC) column. We optimized the precursor ions, product ions, mobile phase composition and gradient program, flow rate, and column temperature. Seven monosaccharides (D-Ribose, L-Arabinose, D-Xylose, D-Fructose, D-Mannose, D-Galactose and D-Glucose) were able to be separated and quantified. We validated the method and the seven molecules showed favorable limits of detection and quantification, recovery rates, carry-over effects, intra- and inter-day accuracy and precision, resolution, and measurement uncertainty. We analyzed human serum samples using the method. To avoid ion suppression and D-d2-Glucose peak interference, compounds present at concentrations outside of the calibration range were analyzed from diluted samples. Quantification of serum samples corroborated some previous clinical research, in that increased D-Glucose concentration was associated with increased concentrations of D-Mannose and D-Ribose. We also validated the CRMs, and expect these to have utility as standards for serum monosaccharide profiling, thus contributing to public health.

Comparison of occupational health problems of employees and self-employed individuals who work in different fields.

We used a representative sample of the working population of Korea to compare the occupational health problems of employees and self-employed individuals who performed different types of work. The Korean Working Conditions Survey (KWCS) of 2014 was used to compare the working conditions and occupational safety and health (OSH) issues of employees and self-employed individuals performing different types of work. Relative to paid employees, self-employed individuals were older, more likely to perceive their health as bad, and had less education, longer working hours, more exposure to workplace ergonomic hazards, more musculoskeletal problems, and poorer mental well-being. Relative to those performing "mental work" or "emotional work", individuals performing "physical work" were more vulnerable to OSH problems. In conclusion, self-employed individuals in the sample were more vulnerable to OSH problems.

Nonstandard workers and differential occupational safety and health vulnerabilities.

BACKGROUND: Permanent jobs are in decline world-wide, and are being replaced with temporary, casual, part-time, and contract jobs. We investigated the characteristics and occupational safety and health (OSH) vulnerabilities of workers with nonstandard and standard employment. METHODS: We used the Korean Working Conditions Survey of 2017 to compare working conditions and OSH vulnerabilities of workers with standard and nonstandard employment in five major job categories. RESULTS: Workers with nonstandard employment were older, less educated, had lower monthly incomes, were employed in smaller businesses, worked fewer hours per week, had shorter work durations, and were more likely to report exposure to physical/chemical and ergonomic hazards, and musculoskeletal and mental symptoms. Among nonstandard workers, the rates of occupational hazards and work-related health problems depended on the type of work performed. In particular, nonstandard male workers who were unskilled manual workers, older, had less education, and earned low wages had a greater risk of working in unstable occupations, greater exposures to occupational hazards, and more musculoskeletal pain (back pain: odds ratio [OR], 2.4; upper extremity pain: OR, 2.1; and lower extremity pain: OR, 1.7) than those performing other types of work. CONCLUSION: Male unskilled manual workers with nonstandard employment were most vulnerable to OSH problems. Our findings suggest the need for OSH programs that specifically target nonstandard workers especially those in manual unskilled occupations.

A rapid non-target screening method for determining prohibited substances in human urine using liquid chromatography/high-resolution tandem mass spectrometry.

Target analysis using liquid chromatography-tandem mass spectrometry is applied for rapidly detecting various prohibited doping substances. Frequent modification is required as additional substances are prohibited. We developed and validated a non-target screening method requiring no further modification because it analyzes the full spectrum of data in fixed m/z ranges. Urine samples were extracted using solid-phase extraction and analyzed by employing a method that combines full scan and variable data independent acquisition using high-resolution mass spectrometry; and all prohibited substances in the urine samples were successfully detected using our screening method. The method was validated in terms of specificity (no interferences), recoveries (29%-131%), matrix effects (35%-237%), limites of detection (0.0002-100 ng/mL), and intra- and inter-day precisions (coefficients of variation lower than 25%). The applicability of this method to doping tests was evaluated by analyzing 14 urine samples. As a result, the non-target screening method is efficient for conducting anti-doping tests because it can be applied without any further modification to prohibited drugs as well as to unknown targets that can be prohibited in the future.

Work Sectors with High Risk for Work-Related Musculoskeletal Disorders in Korean Men and Women.

BACKGROUND: To identify work sectors with high risk for work-related musculoskeletal disorders (MSDs) in Korean men and women. METHODS: We analyzed nationwide data to identify ergonomic risk factors in Korean employees. In particular, we analyzed data on exposure to five ergonomic risk factors (painful/tiring postures, lifting/moving heavy materials, standing/walking, repetitive hand/arm movements, and hand/arm vibration) according to employment sector, sex, and age, using the 2014 Fourth Korean Working Conditions Survey. We also used workers' compensation data on work-related MSDs in 2010, which is available by sex. RESULTS: The different work sectors had different gender distributions. "Manufacturing" (27.7%) and "construction" (11.3%) were dominated by males, whereas "human health and social work activities" (12.4%), "hotel and restaurants" (11.7%), and "education" (10.4%) were dominated by females. However, "wholesale and retail trade" and "public administration and defense" employed large numbers of males and females. Furthermore, the work sectors with a greater proportion of work-related MSDs and with multiple ergonomic risk factors were different for men and women. For men, "construction" and "manufacturing" had the highest risk for work-related MSDs; for women, "hotel and restaurants" had the highest risk for work-related MSDs. CONCLUSION: Ergonomic interventions for workers should consider gender and should focus on work sectors with high risk for MSDs, with multiple ergonomic risk factors, and with the largest number of workers.

Association of Job Satisfaction and Security With Subjective Health and Well-Being in Korean Employees.

OBJECTIVES: We evaluated an association of workplace exposure to physical factors (physical, chemical, and ergonomic hazards) and psychosocial factors, and of job satisfaction and job security with the subjective health and well-being of Korean workers. METHODS: This was a secondary analysis of data from the fourth Korean Working Conditions Survey of 2014. RESULTS: Exposure to physical factors (especially ergonomic factors) and psychosocial factors were negatively associated with good subjective health and well-being. After adjustment for confounding by physical factors and psychosocial factors, job satisfaction and job security were positively associated with good subjective health and well-being. CONCLUSION: Korean workers with high job satisfaction and job security are more likely to have good subjective health and well-being, even when they are exposed to physical and psychosocial workplace factors. However, job satisfaction cannot be treated as a proxy for good working conditions.

Self-employed individuals performing different types of work have different occupational safety and health problems.

INTRODUCTION: We assessed the occupational safety and health (OSH) issues of self-employed individuals in Korea. METHODS: The working conditions and OSH issues in three groups were analyzed using the Korean Working Conditions Survey of 2014. RESULTS: Among self-employed individuals, "Physical work" was more common among males, whereas "Emotional work" was more common among females. Self-employed individuals performing "Mental work" had more education, higher incomes, and the lowest exposure to physical/chemical and ergonomic hazards in the workplace. In contrast, those performing "Physical work" were older, had less education, lower incomes, greater exposure to physical/chemical and ergonomic hazards in the workplace, and more health problems. Individuals performing "Physical work" were most vulnerable to OSH problems. CONCLUSION: The self-employed are a heterogeneous group of individuals. We suggest development of specific strategies that focus on workers performing "Physical work" to improve the health and safety of self-employed workers in Korea.

Long Working Hours in Korea: Based on the 2014 Korean Working Conditions Survey.

BACKGROUND: Long working hours adversely affect worker safety and health. In 2004, Korea passed legislation that limited the work week to 40 hours, in an effort to improve quality-of-life and increase business competitiveness. This regulation was implemented in stages, first for large businesses and then for small businesses, from 2004 to 2011. We previously reported that average weekly working hours decreased from 2006 to 2010, based on the Korean Working Conditions Survey. METHODS: In the present study, we examine whether average weekly working hours continued to decrease in 2014 based on the 2014 Korean Working Conditions Survey. RESULTS: The results show that average weekly working hours among all groups of workers decreased in 2014 relative to previous years; however, self-employed individuals and employers (who are not covered by the new legislation) in the specific service sectors worked > 60 h/wk in 2014. CONCLUSION: The Korean government should prohibit employees from working excessive hours and should also attempt to achieve social and public consensus regarding work time reduction to improve the safety, health, and quality-of-life of all citizens, including those who are employers and self-employed.

Vulnerability of employees in businesses with fewer than five workers (micro-enterprises) to occupational safety and health problems.

INTRODUCTION: We assessed the characteristics of micro-enterprises (businesses with fewer than five workers) focusing on occupational safety and health (OSH) issues. METHODS: We performed a secondary analysis of data from the Economically Active Population Supplementary Survey and the fourth Korean Working Conditions Survey of 2014. RESULTS: Relative to larger businesses, micro-enterprises employ more women, temporary workers, and older workers (>55 years). In addition, more workers in micro-enterprises held "elementary occupations" (unskilled or under-skilled) or "sales and service jobs." Key sectors of such employment included the sectors of "wholesale and retail trade" and "hotel and restaurants." Furthermore, lower skilled workers in such micro-enterprises more frequently reported exposure to ergonomic risk factors and subsequent musculoskeletal disorders, and they also experienced a much higher fatality rate due to occupational injuries. CONCLUSION: Our results indicate that Korean workers in micro-enterprises are more vulnerable to OSH problems than workers in larger businesses.

NLRP3 Inflammasome Contributes to Lipopolysaccharide-induced Depressive-Like Behaviors via Indoleamine 2,3-dioxygenase Induction.

Background: Inflammation may play a significant role in the pathogenesis of depression, although the molecular target for the treatment of inflammation-mediated depressive symptoms remains to be elucidated. Recent studies have implicated the NLRP3 inflammasome in various psychiatric disorders, including depression. However, the underlying mechanism by which NLRP3 inflammasome activation mediates the progression of depressive-like behaviors remains poorly understood. Methods: We examined whether NLRP3 deficiency influenced depressive-like behaviors and cerebral inflammation following systemic administration of lipopolysaccharide in mice. To further assess the contribution of the NLRP3 inflammasome to the progression of depression, we evaluated the effects of NLRP3 signaling on levels of indoleamine 2,3-dioxygenase. Results: Nlrp3-deficient mice exhibited significant attenuation of depressive-like behaviors and cerebral caspase-1 activation in a lipopolysaccharide-induced model of depression. Treatment with the antidepressant amitriptyline failed to block NLRP3-dependent activation of caspase-1, but inhibited lipopolysaccharide-promoted production of interleukin-1ß mRNA via suppressing NF-κB signaling in mouse mixed glial cultures. Interestingly, lipopolysaccharide administration produced NLRP3-dependent increases in indoleamine 2,3-dioxygenase expression and activity of mouse brain. Furthermore, inflammasome-activating stimulations, but not treatment with the inflammasome product interleukin-1ß, triggered indoleamine 2,3-dioxygenase mRNA induction in mixed glial cells. Conclusions: Our data indicate that the NLRP3 inflammasome is significantly implicated in the progression of systemic inflammation-induced depression. NLRP3-dependent caspase-1 activation produced significant increases in indoleamine 2,3-dioxygenase levels, which may play a significant role in lipopolysaccharide-induced depression. Collectively, our findings suggest that indoleamine 2,3-dioxygenase is a potential downstream mediator of the NLRP3 inflammasome in inflammation-mediated depressive-like behaviors.

Hazards and health problems in occupations dominated by aged workers in South Korea.

BACKGROUND: South Korea's population is aging more rapidly than any other country. Aging of the productive population will lead to shortage of labor and the decreasing quality of the labor force in South Korea. South Korea needs health care strategies to support the establishment of work environments that are appropriate for elderly workers who have reduced physical capacity. This paper aims to identify occupations that are dominated by aged workers and assess the exposure to hazards and work-related health problems of aged workers in these occupations. METHODS: We identified the 20 occupations in South Korea that employ the most aged workers (at least 55 years-old), among all 149 occupations that are defined as minor categories (identified by three digits) by the Korean Standard Classification of Occupations (KSCO). Exposure to hazards and work-related health problems of individuals in these occupations were evaluated by analyzing the results of the fourth Working Conditions Survey of 2014. RESULTS: Among the 20 occupations that employ the most aged workers, 'Elementary Occupations', which the KSCO classifies as major category (9), had the largest proportion of aged workers. After this, there were five occupations of skilled manual workers and six occupations of skilled non-manual workers. Aged workers in elementary and skilled manual occupations reported frequent exposure to job-specific hazards, such as noise, vibrations, high and low temperatures, solvents, and chemicals. Relative to other workers, aged workers in the occupations reported more frequent exposure to ergonomic hazards, such as tiring or painful positions, carrying or moving heavy loads, and repetitive movements, and also reported more work-related musculoskeletal disorders and general fatigue. Injury due to accident was common in machinery-handling occupations. CONCLUSION: Job-specific hazards should be reduced to prevent occupation-related disorders in elementary and skilled manual occupations that are dominated by aged workers.

Gender differences in occupations and complaints of musculoskeletal symptoms: Representative sample of South Korean workers.

INTRODUCTION: The present study examines gender differences in occupations, occupational hazards, and musculoskeletal symptoms in Korean workers. METHODS: We performed a secondary analysis of data from the fourth Korean Working Conditions Survey (KWCS). RESULTS: Relative to "managers," men who were "craft and related trades workers," "equipment, machine operating and assembling workers," and in "elementary occupations" were more likely to report back pain (ORs: 2.08, 2.33, and 2.71, respectively); women who were "skilled agricultural, forestry, and fishery workers" were more likely to report back pain (OR: 3.96). Back pain was more likely to be reported in men exposed to "carrying/moving heavy loads," "painful/tiring postures," and "repetitive hand/arm movements" (ORs: 1.20, 2.26, and 1.28, respectively). CONCLUSION: Men and women workers differed in their reporting of ergonomic risk factors, and complaints of musculoskeletal symptoms. Am. J. Ind. Med. 60:342-349, 2017. © 2017 Wiley Periodicals, Inc.