Biomedical subjects

Akinori Nakata

Publications and source records attributed to Akinori Nakata.

4 recordsLinked to original sources

PubMed2002

Disturbed sleep-wake patterns during and after short-term international travel among academics attending conferences.

OBJECTIVES: To examine variations in sleep and wakefulness associated with international travel. METHODS: Ten academics in Japan were studied while traveling abroad to participate in conferences. Wrist activity and a daily log were recorded continuously for 1 week before, during, and for 1 week after travel. Destinations included the USA and Canada to the east (8 to 11-h time difference; mean stay of 6.8 days) and Europe to the west (7 to 8-h time difference; mean stay of 6.0 days). RESULTS: For eastward-traveling subjects, the total sleep time was shorter and the mean activity during sleep was greater at the destinations than before departure. These sleep disruptions persisted until the 2nd day after the subjects had returned home. The sleep patterns then recovered in a zigzag manner. No significant disruptions in the main sleep were found in westward travelers, although these subjects took a longer nap immediately after their return. The beginning and end of sleep occurred earlier until the 2nd day after the subjects had returned from eastward trips, but occurred later until the 5th day after return from westward trips. CONCLUSIONS: In academics, short-term international travel causes sleep disturbances both during and at home after eastward travel and a delay in the sleep timing at home after westward travel. Although the subjects in this study might be atypical of business travelers, the current data suggest that strategies are needed to facilitate recovery from disturbed sleep-wake patterns at home after travel, i.e., redesign of post-travel work schedules.

Adult↗

PubMed2002

[Willingness to implement mental health measures among small-scale enterprise employers in Ohta ward, Tokyo, Japan].

Due to the increase in mental health problems among Japanese workers in recent years, effective approaches to address these problems are of growing concern. Although such an effort is now under way in largescale enterprises (LSEs), small-scale enterprises (SSEs) are lagging behind LSEs for a number of reasons. In the present study, to know the reason, the presidents of 263 SSEs (fewer than 50 employees) in the Ohta ward of Tokyo were surveyed with a self-administered questionnaire from October 1999 to March 2000 (response rate, 51.0%). The main business types were manufacturing (71.2%), transportation & storage (6.1%), and construction (5.3%). The results revealed that employers attribute the mental health problems of employees to "Job content/Aptitude for job (78.6%)", "Communication among employees (71.0%)", "Physical problems/Illness (50.4%)", "Family problems (33.6%)". These results are very similar to those obtained in the same enterprises employees survey in 1996, suggesting that employers perceive the factors responsible for employees' mental health problems with substantial accuracy. Sixty-nine point five percent of the employers answered that they need mental health measures for employees. And 62.7% of employers agreed to take mental health measures in their enterprises. Taken together, it is considered that employers are willing to improve their employees' mental health problems. Nevertheless, 95% of employers are doing nothing to improve the situation. The major reasons cited were 1) Cannot obtain a consultant or counselor (44.8%), 2) Lack of time (43.1%), 3) Manpower shortage (41.4%), 4) Difficulty in ensuring employees' privacy (36.2%), and 5) Lack of financial resources (30.2%). The results of the present study suggest that perception of the mental health problems among employers and employees of SSEs in the Ohta area were close to each other. Effective strategies are needed to improve mental health problems in SSEs.

Attitude↗

PubMed2002

Association of low job control with a decrease in memory (CD4+ CD45RO+) T lymphocytes in Japanese middle-aged male workers in an electric power plant.

To clarify the relationship between perceived job stress and lymphocyte subpopulations, a cross-sectional study was conducted in 231 male electric power plant workers (aged 40 to 60, mean 46 years). Job stress, i.e., job control, job demands, and social support at work, was assessed by means of the Japanese version of the Job Content Questionnaire. Blood samples were taken from all the workers, and numbers of CD4+ T lymphocyte subpopulations, total CD4+ T, T (CD3+) lymphocytes, CD16CD56+ natural killer (NK) cells, total lymphocytes, and white blood cells were determined. After controlling for age, number of cigarettes smoked per day, alcohol drinking, frequency of regular exercise, job demands, and social support at work by the partial correlation coefficients, numbers of memory (CD4+ CD45RO+) T, total CD4+ T, and total T (CD3+) lymphocytes were positively correlated with job control (p<0.05). Neither job demands nor social support at work showed significant correlations with lymphocyte subpopulations. It is suggested that lower job control is associated with a decrease in the number of CD4+ CD45RO+ T lymphocytes in male middle-aged workers.

Adult↗

PubMedDate not supplied

Psychological stress increases human T cell apoptosis in vitro.

OBJECTIVES: Recent studies have shown that apoptosis is involved in stress responses. The present study examined if stressors increase in vitro apoptosis of peripheral blood T lymphocytes in a dose-dependent manner. METHODS: Daily subjective stress was quantitatively analyzed in 40 nonsmoking men with a daily hassles questionnaire. Apoptosis of T lymphocytes was measured by flowcytometry using Annexin V/PI double staining method after 0, 12, and 24 h of culture in the presence or absence of dexamethasone (DEX). Using a cross-sectional design, the current study examined the relationship between stress and in vitro apoptosis of T cells. RESULTS: Results showed that apoptosis of T lymphocytes in vitro has a significant correlation with stress and age. Stress was positively correlated with percentage of apoptosis in T cells after 12 h of culture, irrespective of DEX treatment. Age was positively correlated with the percentage of T cell apoptosis after 0 and 12 h of coculture with DEX. CONCLUSIONS: These results indicate that age-related apoptosis and stress-related apoptosis of T cells are modulated through different mechanisms. This is the first study to show that in vitro lymphocyte apoptosis is influenced by daily stress in a dose-dependent manner.

Activities of Daily Living↗