The ever-changing social implications of the COVID-19 pandemic have resulted in an urgent need to understand the working environments and health status of workers. We conducted a nationwide Internet-based health survey in Japanese workers in December 2020, in the midst the country's "third wave" of COVID-19 infection. Of 33,087 surveys collected, 6,051 were determined to have invalid responses. The 27,036 surveys included in the study were balanced in terms of geographical area, participant sex, and type of work, according to the sampling plan. Men were more likely than women to have telecommuted, while women were more likely to have resigned since April 2020. Moreover, 40% and 9.1% of respondents had a K6 score of 5 or higher and 13 or higher, respectively, they did not exhibit extremely poor health. The present study describes the protocol used to conduct an Internet-based health survey in workers and a summary of its results during a period when COVID-19 was spreading rapidly in Japan. In the future, we plan to use this survey to examine the impact of COVID-19 on workers' work styles and health.

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We previously investigated the utility of μ-oxo N,N′- bis(salicylidene)ethylenediamine iron (Fe(Salen)) nanoparticles as a new anti-cancer agent for magnet-guided delivery with anti-cancer activity. Fe(Salen) nanoparticles should rapidly heat up in an alternating magnetic field (AMF), and we hypothesized that these single-drug nanoparticles would be effective for combined hyperthermia-chemotherapy. Conventional hyperthermic particles are usually made of iron oxide, and thus cannot exhibit anti-cancer activity in the absence of an AMF. We found that Fe(Salen) nanoparticles induced apoptosis in cultured cancer cells, and that AMF exposure enhanced the apoptotic effect. Therefore, we evaluated the combined three-fold strategy, i.e., chemotherapy with Fe(Salen) nanoparticles, magnetically guided delivery of the nanoparticles to the tumor, and AMF-induced heating of the nanoparticles to induce local hyperthermia, in a rabbit model of tongue cancer. Intravenous administration of Fe(Salen) nanoparticles per se inhibited tumor growth before the other two modalities were applied. This inhibition was enhanced when a magnet was used to accumulate Fe(Salen) nanoparticles at the tongue. When an AMF was further applied (magnet-guided chemotherapy plus hyperthermia), the tumor masses were dramatically reduced. These results indicate that our strategy of combined hyperthermia-chemotherapy using Fe(Salen) nanoparticles specifically delivered with magnetic guidance represents a powerful new approach for cancer treatment.

Research on controlled drug delivery for cancer chemotherapy has focused mainly on ways to deliver existing anti-cancer drug compounds to specified targets, e.g., by conjugating them with magnetic particles or encapsulating them in micelles. Here, we show that an iron-salen, i.e., μ-oxo N,N'- bis(salicylidene)ethylenediamine iron (Fe(Salen)), but not other metal salen derivatives, intrinsically exhibits both magnetic character and anti-cancer activity. X-Ray crystallographic analysis and first principles calculations based on the measured structure support this. It promoted apoptosis of various cancer cell lines, likely, via production of reactive oxygen species. In mouse leg tumor and tail melanoma models, Fe(Salen) delivery with magnet caused a robust decrease in tumor size, and the accumulation of Fe(Salen) was visualized by magnetic resonance imaging. Fe(Salen) is an anti-cancer compound with magnetic property, which is suitable for drug delivery and imaging. We believe such magnetic anti-cancer drugs have the potential to greatly advance cancer chemotherapy for new theranostics and drug-delivery strategies.

Objectives: On December 1, 2015, the Japanese government launched the Stress Check Program, a new occupational health policy to screen employees for high psychosocial stress in the workplace. As only weak evidence exists for the effectiveness of the program, we sought to estimate the risk of stress-associated long-term sickness absence as defined in the program manual. Methods: Participants were 7356 male and 7362 female employees in a financial service company who completed the Brief Job Stress Questionnaire (BJSQ). We followed them for 1 year and used company records to identify employees with sickness absence of 1 month or longer. We defined high-risk employees using the BJSQ and criteria recommended by the program manual. We used the Cox proportional regression model to evaluate the prospective association between stress and long-term sickness absence. Results: During the follow-up period, we identified 34 male and 35 female employees who took long-term sickness absence. After adjustment for age, length of service, job type, position, and post-examination interview, hazard ratios (95% confidence intervals) for incident long-term sickness absence in high-stress employees were 6.59 (3.04-14.25) for men and 2.77 (1.32-5.83) for women. The corresponding population attributable risks for high stress were 23.8% (10.3-42.6) for men and 21.0% (4.6-42.1) for women. Conclusions: During the 1-year follow-up, employees identified as high stress (as defined by the Stress Check Program manual) had significantly elevated risks for long-term sickness absence.

ObjectivesRecent epidemiological research in Europe has reported that two groups of job demands, i.e., challenges and hindrances, are differently associated with work engagement. The purpose of the present study was to replicate the cross-sectional association of workload and time pressure (as a challenge) and role ambiguity (as a hindrance) with work engagement among Japanese employees.MethodsBetween October 2010 and December 2011, a total of 9,134 employees (7,101 men and 1,673 women) from 12 companies in Japan were surveyed using a self-administered questionnaire comprising the Job Content Questionnaire, National Institute for Occupational Safety and Health Generic Job Stress Questionnaire, short 10-item version of the Effort-Reward Imbalance Questionnaire, short nine-item version of the Utrecht Work Engagement Scale, and demographic characteristics. Multilevel regression analyses with a random intercept model were conducted.ResultsAfter adjusting for demographic characteristics, workload and time pressure showed a positive association with work engagement with a small effect size (standardized coefficient [β] = 0.102, Cohen’s d [d] = 0.240) while role ambiguity showed a negative association with a large effect size (β = −0.429, d = 1.011). After additionally adjusting for job resources (i.e., decision latitude, supervisor support, co-worker support, and extrinsic reward), the effect size of workload and time pressure was not attenuated (β = 0.093, d = 0.234) while that of role ambiguity was attenuated but still medium (β = −0.242, d = 0.609).ConclusionsAmong Japanese employees, challenges such as having higher levels of workload and time pressure may enhance work engagement but hindrances, such as role ambiguity, may reduce it.

This study reveals a strong positive association between work-related psychosocial factors and an elevated risk of metabolic syndrome onset. The effects of job strain and shift work on metabolic syndrome appear to be significant.

We previously reported that μ-oxo N,N’-bis(salicylidene)ethylenediamine iron [Fe(Salen)], a magnetic organic compound, has direct anti-tumor activity, and generates heat in an alternating magnetic field (AMF). We showed that Fe(Salen) nanoparticles are useful for combined hyperthermia-chemotherapy of tongue cancer. Here, we have examined the effect of Fe(Salen) on human glioblastoma (GB). Fe(Salen) showed in vitro anti-tumor activity towards several human GB cell lines. It inhibited cell proliferation, and its apoptosis-inducing activity was greater than that of clinically used drugs. Fe(Salen) also showed in vivo anti-tumor activity in the mouse brain. We evaluated the drug distribution and systemic side effects of intracerebrally injected Fe(Salen) nanoparticles in rats. Further, to examine whether hyperthermia, which was induced by exposing Fe(Salen) nanoparticles to AMF, enhanced the intrinsic anti-tumor effect of Fe(Salen), we used a mouse model grafted with U251 cells on the left leg. Fe(Salen), BCNU, or normal saline was injected into the tumor in the presence or absence of AMF exposure. The combination of Fe(Salen) injection and AMF exposure showed a greater anti-tumor effect than did either Fe(Salen) or BCNU alone. Our results indicate that hyperthermia and chemotherapy with single-drug nanoparticles could be done for GB treatment.