Heart rate variability assessment in Japanese workers recovered from depressive disorders resulting from job stress: measurements in the workplace.

PURPOSE: The purpose of this study is to clarify workers' autonomic nerve balance after long-term sick leave due to depressive disorders resulting from job stress compared with healthy workers. METHODS: The participants were 28 Japanese male workers recovered from depressive disorders and 75 healthy male workers. For each participant, the lifestyle and the fatigue within 1 month were assessed by a checklist. Heart rate variability (HRV) was measured at the workplace by acceleration plethysmography (APG). HRV was assessed by the coefficient of variation of rate intervals (CV), the spectral components in the high- and low-frequency areas represented by the normalized HF and LF (nHF and nLF), and the ratio of LF to HF components (LF/HF). RESULTS: There was no significant difference in individual lifestyle and fatigue symptoms between the recovered and the healthy workers. The former workers showed significantly lower CV, higher nLF and log(10)LF/HF, and lower nHF that represent the predominance of sympathetic activity in comparison with the healthy workers. Moreover, the recovered workers who discontinued medications indicated significantly higher nLF and log(10)LF/HF, and lower nHF compared to the recovered workers who continued their medications. CONCLUSIONS: Recovered workers in the workplace tended to show the depressive HRV feature that is the dominant sympathetic activity compared with the healthy workers. They might still be showing job stress that was not detected by the checklist. HRV analyses by APG in addition to questionnaire has the potential to become an effective approach for assessing workers' job stress to prevent repeated absences.

[Qualitative evaluation of employer requirements associated with occupational health and safety as good practice in small-scale enterprises].

The purpose of this study was to identify what motivates employers to promote good occupational health and safety practices in small-scale enterprises. Previous studies have shown that small-scale enterprises generally pay insufficient attention to issues of occupational health and safety. These findings were mainly derived from questionnaire based surveys. Nevertheless, some small-scale enterprises in which employers exercise good leadership do take a progressive approach to occupational health and safety. Although good practices can be identified in small-scale enterprises, it remains unclear what motivates employers in small-scale enterprises to actively implement occupational health and safety practices. We speculated that identifying employer motivations in promoting occupational health would help to spread good practices among small-scale enterprises. Using a qualitative approach based on the KJ methods, we interviewed ten employers who actively promote occupational health and safety in the workplace. The employers were asked to discuss their views of occupational health and safety in their own words. A semi-structured interview format was used, and transcripts were made of the interviews. Each transcript was independently coded by two or more researchers. These transcripts and codes were integrated and then the research group members discussed the heading titles and structural relationships between them according to the KJ method. Qualitative analysis revealed that all the employers expressed a strong interest in a "good company" and "good management". They emphasized four elements of "good management", namely "securing human resources", "trust of business partners", "social responsibility" and "employer's health condition itself", and considered that addressing occupational health and safety was essential to the achievement of these four elements. Consistent with previous findings, the results showed that implementation of occupational health and safety activities depended on "cost", "human resources", "time to perform", and "advisory organization". These results suggest that employer awareness of the relationship between good management and occupational health is essential to the implementation of occupational health and safety practices in small-scale enterprises.

Stationarity of the heart rate variability by acceleration plethysmography: short-term measurements of healthy young males in daily life.

The acceleration plethysmography (APG) is a useful tool to analyze the heart rate variability (HRV) with the merits of being portable and simple in operation. To use it clinically, 'stationarity' of the HRV measurements in resting state should be justified as a fundamental premise. Therefore, the purpose of this research was to investigate the stationarity of the short-term HRV derived from APG in resting state in daily life. The sample size was determined on the basis of alpha = 0.05 and beta = 0.20. The HRV measurements of 44 healthy male subjects were done twice during a one-week period by the APG system. The HRV parameters were examined by the assessments of distribution, equality of the mean and variance and internal consistency reliability. Concerning spectral components represented as proportion, normalized units and the logarithm of the rate of each component, the normal distribution and the homogeneity of variance in two measurements were confirmed. Significant difference was not found between the mean values in two measurements. The internal consistency reliability evaluated by Cronbach's alpha of 0.6-0.7 was acceptable for every parameter. It is concluded that for healthy young males, the parameters of short-term HRV derived from APG measured in resting state in the same time zone in daily life remain stationary within a certain range regardless of the measurement day.

The challenges of occupational health service centers in Japan.

The improvement of occupational health conditions in Small- and medium-scale enterprises (SMEs) is the most crucial issue in occupational health in Japan today. Improvement will depend on how occupational health services are provided to SMEs. Recently, Occupational Health Service Centers (OHSCs) providing occupational health services for SMEs have become more firmly established and expectations for further improvement in quality and quantity are high. In this way it is hoped that the challenges of providing "occupational health for all" can be met.

Depression of the apparent chiral recognition ability obtained in the host-guest complexation systems by electrospray and nano-electrospray ionization mass spectrometry.

Chiral recognition in the host-guest complexation systems of chiral crown ether hosts and amino ester guests was thoroughly examined using the electrospray ionization (ESI) mass spectrometry/enantiomer labeled (EL)-guest method. In this method, the mass spectra of a mixture of three components in a solution, a chiral host (H), an equal amount of an (S)-enantiomer guest labeled with deuterium atoms (G(S-dn)(+)) and an unlabeled (R)-enantiomer guest (G(R)+), were measured and the relative peak intensity value [I(H + G(R))(+) / I(H + G(S-dn))(+) = IRIS] of the host-guest complex ions, observed with an excess guest concentration, was taken to provide the chiral recognition ability of the host. In our earlier report (1996), we demonstrated that the apparent chiral recognition abilities using a mass spectrometer with a homemade ESI interface were depressed by about one tenth compared with the corresponding abilities obtained by fast-atom bombardment (FAB) MS. In the present study, the enantioselective complexation behaviors of various combinations of chiral crown hosts with chiral guests were further investigated in detail mainly using a modern commercial ESI/ion trap (IT) mass spectrometer. Consequently, it was found that the apparent IRIS values from the ESI-MS/EL-guest method changed significantly, depending upon the instrument used, and in particular, upon the ESI interfaces. Moreover, under the specific measuring conditions in ESI-IT-MS, the degrees of depression of the apparent chiral recognition abilities are roughly grouped into three classes, depending upon the number (or probably the type) of the hydrophobic substituents of the hosts. Representing the degrees by the slopes when plotting the apparent IRIS values in ESI-MS versus those in FAB-MS, the slopes for the three classes are (1) 1.0, (2) 0.7 and (3) 0.3; the higher the hydrophobicity of the hosts (and then, the host-guest complex ions), the lower the slope (the apparent enantioselectivity). Strengthening the degree of depression may be caused by an increase in the local concentration of the host close to the surface of the droplets produced during the electrospary ionization process. The chiral recognition ability (K(R )/ K(S)) in an equilibrated solution agrees quite well with the IRIS value in FAB-MS rather than that in ESI-MS.