A comparison of periodic health examinations and workplace health screening for workers in Singapore and Japan.

This article aims to provide a historical overview of how workplace safety and health legislations in Singapore and Japan have evolved, and perform a comparative analysis of the occupational health systems where work-related medical examinations and health screening are concerned. The discourse is centered on three key themes - coverage, comprehensiveness, and continuity of care. The comparative analysis was performed based on secondary data obtained from open-source platforms. Singapore and Japan have robust workplace safety and health legislative frameworks and laws. However, their approaches diverge because of differing socioeconomic and political contexts. Japan's regulations are generally more comprehensive, require more frequent monitoring of workers' health status, and encompass both physical and mental health components. Singaporean companies focus primarily on the physical component of health, and statutory examinations are required only for exposure to specific occupational hazards. With increasing prominence of mental health issues and shift towards preventive care in Singapore, there will be greater emphasis on a holistic approach to each employee's overall health in future. For Japan, the challenge would be to strike a balance between long-term sustainability of current policies against the need for state and corporations to still retain an adequate stake in ensuring workers' overall health.

[The history of compensation system for workers with pneumoconiosis-related lung cancer].

OBJECTIVE: To review the historical aspects of compensation system for workers with pneumoconiosis who developed lung cancer. METHODS: Materials and papers published on the compensation system as discussed in administrative meetings were utilized. RESULTS: Legal claims for compensation for lung cancer among individuals with pneumoconiosis increased during the period of rapid economic growth in Japan. A possible causal relationship between pneumoconiosis and lung cancer in workers has been discussed by committees of specialists. The Expert Committee on Pneumoconiosis and Lung Cancer in 1978 did not find a causal relationship between them. However, a survey of physicians specializing in pneumoconiosis revealed medical disadvantages among individuals diagnosed with pneumoconiosis who developed lung cancer. The Ministry of Labour announced the risk of work-related lung cancer in patients with advanced pneumoconiosis (class IV or equivalent severity). Since then, numerous lung cancer patients with pneumoconiosis have been adjudicated. In 1997, the International Agency for Research on Cancer (IARC) re-evaluated the carcinogenicity of silica and declared it to be a Group I carcinogen in humans. The Expert Committee on Compensation of Lung Cancer Cases Developing from Pneumoconiosis discussed the IARC evaluation but did not accept this classification. However, the Committee of Occupational Exposure Limits in the Japan Society of Occupational Health upheld the IARC evaluation of silica as a Group I carcinogen. Because the Expert Committee of Medical Disadvantage of Lung Cancer Patients with Pneumoconiosis accepted the increased risk of lung cancer in patients with class III or equivalent severity pneumoconiosis, the Ministry of Labour announced worker compensation for such patients. The Expert Committee of Health Control of Pneumoconiosis Complicated with Lung Cancer reported in 2002 that a meta-analysis revealed no increased risk of lung cancer among workers exposed to crystalline silica; however, there was an increased risk of lung cancer in patients with pneumoconiosis. The Ministry of Labour has added lung cancer to the list of complications from pneumoconiosis and, if necessary, regular medical checkups for lung cancer. After Leaving dust work, the Health Care System provides for workers who are diagnosed With class II or higher pneumoconiosis. Therefore, if an individual with pneumoconiosis develops class II or higher lung cancer, that individual becomes eligible for workers' compensation. CONCLUSIONS: The conclusion of the Expert Committee in 2002 and the decision of the Ministry of Labour to add lung cancer to its list of complications of pneumoconiosis are evaluated to be appropriate.

IL-6-Mediated Upregulated miRNAs in Extracellular Vesicles Derived from Lund Human Mesencephalic (LUHMES) Cells: Effects on Astrocytes and Microglia.

Psychological stress plays a major role in depression, and interleukin-6 (IL-6) is elevated during depression and psychological stress. MicroRNAs (miRNAs) in extracellular vesicles (EVs), including exosomes and microvesicles, suppress mRNA expression in other cells when endocytosed. In this study, we analyzed the effect of IL-6 on EVs secreted by neural precursor cells. Cells from the human immortalized neural precursor cell line LUHMES were treated with IL-6. EVs were collected using a nanofiltration method. We then analyzed the uptake of LUHMES-derived EVs by astrocytes (ACs) and microglia (MG). Microarray analysis of miRNAs was performed using EV-incorporated RNA and intracellular RNA from ACs and MG to search for increased numbers of miRNAs. We applied the miRNAs to ACs and MG, and examined the cells for suppressed mRNAs. IL-6 increased several miRNAs in the EVs. Three of these miRNAs were originally low in ACs and MG (hsa-miR-135a-3p, hsa-miR-6790-3p, and hsa-miR-11399). In ACs and MG, hsa-miR-6790-3p and hsa-miR-11399 suppressed four mRNAs involved in nerve regeneration (NREP, KCTD12, LLPH, and CTNND1). IL-6 altered the types of miRNAs in EVs derived from neural precursor cells, by which mRNAs involved in nerve regeneration were decreased in ACs and MG. These findings provide new insights into the involvement of IL-6 in stress and depression.

Partial cooling of the upper body with a water-cooled vest in an environment exceeding body temperature.

OBJECTIVES: To evaluate the efficacy of water-cooled clothing that continuously cools restricted body areas to suppress body temperature increase as an anti-heatstroke measure for workers in hot environments that exceed body temperature. METHODS: Ten healthy men were placed in Room A (air temperature: 25°C, relative humidity: 50%) for 15 min. They were then transferred to Room B (air temperature: 40°C, relative humidity: 50%), where they rested for 10 min, then put on cooling clothing, and again rested for 15 min (the control group rested for 25 min). They then performed intense ergometer exercise for 40 min at 40% maximal oxygen consumption after which they rested for 10 min. The three trial conditions were CON (long-sleeved summer work clothes), VEST (cooling vest), and P-VEST (partial cooling vest). In VEST and P-VEST, water-cooled clothing continuously recirculated with 10°C water was used to cool the upper body. In P-VEST, only the neck, axillae, and heart areas were in contact with the cooled clothing. The measured indices were the rectal, esophageal, and external auditory canal temperatures; heart rate; estimated sweat volume; and subjective evaluations. RESULTS: Compared with the CON condition, the rectal, esophageal, and external auditory canal temperatures and the heart rate were significantly lower and the subjective indices were decreased in the VEST and P-VEST conditions. CONCLUSIONS: Partial cooling showed a body cooling effect similar to that of whole upper body cooling. Partial body cooling promoted the heat dissipation, suggesting that partial cooling is efficient for maintaining body cooling in hot environments.

Measuring the effects of respiratory protective equipment and other protectors in preventing the scattering of vocalization droplets.

This study was conducted to quantitatively examine the effects of respiratory protective equipment (respirators) and various other types of protectors in preventing the scattering of vocalization droplets. Each of 12 adult male volunteers was asked to vocalize intermittently for 1 min at a target intensity of approximately 100 dBA in an experimental room adjusted to a humidity of approximately 60-70%. The subjects vocalized while wearing respirators, other types of protectors, or no protectors at all. The droplet concentration in a particle size range of 0.3 to 10 µm was measured under each experimental condition, and the transmitted particle concentration and penetration were calculated. The concentration and penetration of particles transmitted from the respirators were lower than those transmitted from the other protectors examined. The probability of infection reduction through the use of the protectors was estimated from the data obtained on the effectiveness of the protectors in preventing the scattering of droplets. We concluded that there is no need for additional droplet scattering prevention in various work settings when appropriate respirators are used under optimal conditions.

Mitigation of heat strain by wearing a long-sleeve fan-attached jacket in a hot or humid environment.

OBJECTIVES: This study examined whether a fan-attached jacket (FAJ) may mitigate the heat strain in hot or humid environment. METHODS: Nine healthy men engaged in 60-min sessions on a bicycle ergometer (4 metabolic equivalents [METs] workload) in hot-dry (40°C and 30% relative humidity) and warm-humid (30°C and 85% relative humidity) environments. Both are equivalent to an approximately 29°C wet-bulb globe temperature. The experiment was repeated-once wearing an ordinal jacket (control condition) and once wearing a long-sleeve FAJ that transfers ambient air at a flow rate of 12 L/s (FAJ condition)-in both environments. RESULTS: Increases in core temperatures in hot-dry environment were not statistically different between control and FAJ; however, that in the warm-humid environment were significantly different between control and FAJ (0.96 ± 0.10°C and 0.71 ± 0.11°C in rectal temperature, P < .0001; and 0.94 ± 0.09°C and 0.61 ± 0.09°C in esophageal temperature, P < .0001). Changes in heart rate were different between control and FAJ in both environments (62 ± 3 bpm and 47 ± 7 bpm, P < .0001 in hot-dry environment; and 61 ± 3 bpm and 46 ± 5 bpm, P < .0001 in the warm-humid environment) and decrease of %weight change was different in hot-dry environment (1.59 ± 0.12% and 1.25 ± 0.05%, P = .0039), but not in the warm-humid environment. CONCLUSIONS: Wearing a FAJ may mitigate heat strain both in hot or humid environments.

Application of tight-fitting half-facepiece breath-response powered air-purifying respirator for internal body cooling in occupational environment.

In dust-generating scenarios in occupational environments, it is important to take measures to prevent not only pneumoconiosis, but also heatstroke. The aim of this study was to verify whether using a tight-fitting half-facepiece breath-response powered air-purifying respirator (PAPR) in combination with a self-produced cooling device could abate the deep body temperature while performing activities. We conducted a crossover study involving 10 subjects. The subjects were subjected to three conditions: wearing a PAPR equipped with a cooling device, PAPR, or a replaceable particulate respirator. During the experiment, the rectal temperature of the subjects was measured, along with the temperature near the PAPR inlet in container with the cooling device when the PAPR equipped with the cooling device was worn. The subjects rested in a cold chamber set at a dry-bulb temperature of 28°C and relative humidity of 45% for 20 min. Then, they moved to a hot chamber set to a dry-bulb temperature of 36°C (with the same relative humidity) in 5 min and exercised on a cycle ergometer for 30 min. After that, the subjects moved to the cold chamber for 5 min and rested for 20 min. Notably, the air inhaled by the subjects wearing PAPR equipped with the cooling device was approximately 10°C cooler than the ambient air. Furthermore, 35 min after the initiation of the experiment (after the middle of the exercise period), the rectal temperature of the participants wearing the PAPR equipped with the cooling device was lower than of those wearing PAPR or replaceable particulate respirators (p <0.05). Thus, we could deduce that the self-produced cooling device was useful in abating deep body temperature. PAPR is useful for its potential applications in hot occupational environments and can save lives in working environments where heat stress can result in major medical complications.

A fan-attached jacket worn in an environment exceeding body temperature suppresses an increase in core temperature.

We examined whether blowing hot air above body temperature under work clothing may suppress core temperature. Nine Japanese men engaged in two 30-min bicycle ergometer sessions at a workload of 40% VO2max at 40 °C and 50% relative humidity. The experiment was conducted without wearing any cooling apparatus (CON), wearing a cooling vest that circulated 10.0 °C water (VEST), and wearing a fan-attached jacket that transferred ambient air underneath the jacket at a rate of 30 L/s (FAN). The VEST and FAN conditions suppressed the increases of rectal temperature (CON, VEST, FAN; 38.01 ± 0.19 °C, 37.72 ± 0.12 °C (p = 0.0076), 37.54 ± 0.19 °C (p = 0.0023), respectively), esophageal temperature (38.22 ± 0.30 °C, 37.55 ± 0.18 °C (p = 0.0039), 37.54 ± 0.21 °C (p = 0.0039), respectively), and heart rate (157.3 ± 9.8 bpm, 136.9 ± 8.9 bpm, (p = 0.0042), 137.5 ± 6.5 bpm (p = 0.0023), respectively). Two conditions also reduced the estimated amount of sweating and improved various subjective evaluations. Even in the 40 °C and 50% relative humidity environment, we may recommend wearing a fan-attached jacket because the heat dissipation through evaporation exceeded the heat convection from the hot ambient air.

Efficacy of ice slurry and carbohydrate-electrolyte solutions for firefighters.

OBJECTIVES: To examine the thermoregulatory and fluid-electrolyte responses of firefighters ingesting ice slurry and carbohydrate-electrolyte solutions before and after firefighting operations. METHODS: Twelve volunteer firefighters put on fireproof clothing and ingested 5 g/kg of beverage in an anteroom at 25°C and 50% relative humidity (RH; pre-ingestion), and then performed 30 minutes of exercise on a cycle ergometer (at 125 W for 10 minutes and then 75 W for 20 minutes) in a room at 35℃ and 50% RH. The participants then returned to the anteroom, removed their fireproof clothing, ingested 20 g/kg of beverage (post-ingestion), and rested for 90 minutes. Three combinations of pre-ingestion and post-ingestion beverages were provided: a 25℃ carbohydrate-electrolyte solution for both (CH condition); 25℃ water for both (W condition); and a -1.7℃ ice slurry pre-exercise and 25℃ carbohydrate-electrolyte solution post-exercise (ICE condition). RESULTS: The elevation of body temperature during exercise was lower in the ICE condition than in the other conditions. The sweat volume during exercise was lower in the ICE condition than in the other conditions. The serum sodium concentration and serum osmolality were lower in the W condition than in the CH condition. CONCLUSIONS: The ingestion of ice slurry while firefighters were wearing fireproof clothing before exercise suppressed the elevation of body temperature during exercise. Moreover, the ingestion of carbohydrate-electrolyte solution by firefighters after exercise was useful for recovery from dehydration.

Technique for continuously monitoring core body temperatures to prevent heat stress disorders in workers engaged in physical labor.

OBJECTIVES: Measuring core body temperature is crucial for preventing heat stress disorders in workers. We developed a method for measuring auditory canal temperatures based on a thermocouple inserted into a sponge-type earplug. We verified that the tip of this thermocouple is positioned safely, allowing the wearer to engage in normal physical tasks; this position averaged 6.6 mm from the tympanic membrane. METHODS: To assess this technique, we had six healthy male students repeat three cycles of exercise and rest (20 min of exercise and 15 min of rest) in a temperature-controlled chamber with temperatures set at 25, 30, or 35 degrees C, while monitoring the auditory canal, esophageal, rectal, and skin temperatures. RESULTS: We observed differences of a mere 0.30-0.45 degrees C between rectal temperatures and auditory canal temperatures measured with the thermocouple, the smallest such difference reported to date in studies involving auditory canal temperature measurement. CONCLUSIONS: We conclude that monitoring temperatures based on a technique involving an auditory canal plug can be used to estimate rectal temperatures accurately, and thereby to avoid conditions leading to heat stress disorders.

Effectiveness of a head wash cooling protocol using non-refrigerated water in reducing heat stress.

Envisioning a cooling method and aiming at maximum feasibility and simplicity, we designed an experimental intervention-control study based on non-refrigerated water usage, consisting of pouring 2 l of 23.0 degrees C water simultaneously on head and hands for one minute, after every 20 min of exertion. The subjects were 11 fit male individuals between 19 and 26 yr old. Each individual participated in one control and one intervention measurement in a climatic chamber at 35 degrees C and 60% humidity (31.5 degrees C WBGT) on different days. Heart rate, rectal, esophageal, skin and external ear canal temperatures were monitored constantly. Each experiment consisted of 10 min of basal recording followed by 3 intervals of 20 min of cycling and 15 min of rest. Stabilometry and visual reaction time tests were performed before and after each resting period. A questionnaire evaluating equilibrium, concentration, alertness and tiredness was administered at the beginning and at the end of every experiment. Paired t-test analysis revealed significant improvements in subjective parameters (all p<0.05), as well as skin (p<0.05), external ear canal (p<0.01) and esophageal (p<0.05) temperatures during the rest periods. Repeated measurement analysis of variance revealed significant cooling in all the aforementioned temperatures except the esophageal temperature (p=0.28). Other parameters were not significantly different. Our findings indicate that this method has subjective and physiologic positive effects, and thus can be used as a complementary low cost method to cool subjects safely.

Heat exposure control using non-refrigerated water in Brazilian steel factory workers.

To test an economically reasonable method to reduce thermal stress, we performed an alternated intervention-control study on 2 groups of 8 male steel workers performing the same jobs, using 2 l of water at ambient temperature (23.5 degrees C +/- 1.4), poured on the head and hands. Each group participated for 2 d as control and 2 d as intervention during 4 consecutive summer days in Brazil, 5 h per shift per day. Testing was done by: 1) recording of temperature by thermistors placed on the external ear canal through earplug, skin (chest, upper arm, inner thigh, outer calf) and clothes; 2) recording of heart rate; and 3) Wet Bulb Globe Temperature recording. The intervention was held hourly, when body weight and water intake were evaluated. Symptoms and subjective sensations were evaluated in the beginning and at the end of each shift. No differences were observed in external ear canal and skin temperatures. Subjective thermal sensation (p = 0.018), sweat perception (p = 0.043), and tiredness (p = 0.028) presented positive statistically significant results when comparing intervention to control measurements. In conclusion, our results could not provide evidence that the proposed method cools the analyzed temperatures, although the subjective evaluation suggests a decrease in the head skin temperature, which could be a useful comfort measure.

[Long working hours and cardiovascular diseases: a systematic review].

Three years have passed since the countermeasures against the adverse health effects of overwork started in Japan, and fruitful outcomes have been expected. In the current study, a systematic review of articles was performed regarding the association of long working hours (LWH) with cardiovascular diseases (CVD) to obtain recent evidence of their association. An electronic database search was conducted using PubMed among English-written original articles published until December, 2004. A total of twelve articles were found conforming to the study's inclusion criteria, but evidence supporting the association of LWH and CVD was not detected. However, some distinctive studies related to the prevention of CVD were found relating to the concept of sensitive psychosocial factors such as vital exhaustion, and to the statistical modeling of occupational factors and biological indicators with the interaction term of psychosocial factors. Further studies will be needed to clarify the association of LWH and CVD.

[Body cooling capacity of water circulated cooling pants during lower body exercise in a hot environment].

We investigated the body cooling capacity of water-circulated cooling pants during lower body exercise in a hot environment. Five subjects were asked to ride a bicycle ergometer and to keep a work rate of 75 W continuously for 20 minutes. They then rest on the ergometer for 15 minutes, in a climate chamber kept at WBGT = 31.5 degrees C. They repeated the same procedure three times under three different conditions; 1) wearing cooling pants with cold water supply; 2) wearing cooling pants without water supply; 3) wearing short pants instead of cooling pants. Esophageal temperature and heart rate of the subjects, when their cooling pants were supplied with cold water, were lower compared with the condition without water supply, and were almost the same as the condition wearing short pants. Water-circulated cooling pants should effectively cool the body at work where the worker has to wear pants that cover his legs to prevent injury.

[A case of malignant gastric outlet stenosis palliated with self-expandable metallic stent and responding to TS-1, an oral fluorouracil derivative].

We report a case of advanced gastric cancer with antral stenosis that responded to an oral anticancer agent, TS-1, after metallic stent insertion. A 59 year-old man was admitted to our hospital because of abdominal distension and vomiting after meals. The diagnosis was advanced gastric cancer with antral stenosis and multiple liver metastases. FP therapy (CDDP 80 mg/m2 day 1 div, 5-FU 700 mg/m2 day 1-5 continuous div) was administered. Although endoscopic findings showed improvement after the first course, the condition of the patient did not improve. We therefore inserted a self-expandable metallic stent into the antral stenosis. After implantation, the patient was able to have regular meals, leave the hospital and return to work. TS-1 (120 mg daily), an oral fluorouracil derivative, was administered in the outpatient setting. A partial response (PR) was obtained after 2 courses with regression of multiple liver metastases and the primary tumor.