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To investigate the reliability and validity of 4 selected scales from the Japanese version of the Job Content Questionnaire (JCQ. Karasek, 1985)-decision latitude, psychological demand, supervisor support, and coworker support-a survey was conducted on a total of 626 employees of telephone and electric companies in Japan. The survey questionnaire was composed of 22 items. Data from 472 male and 108 female respondents were analyzed. Cronbach's alpha coefficients for the four JCQ scales ranged from .61 to .89 for men and from .65 to .87 for women. Scree plots based on factor analyses of scale items indicated that one major factor explained 30% to 75% of each scale variance in men and women. Factor structures of the 22 items for men and women were consistent with those theoretically expected Distributions of the decision latitude scores among occupations for men and women were similar to those in the U.S. national samples; the scores significantly and positively correlated with occupational class. It is suggested that the JCQ scales are reliable and valid instruments for assessing job stressors in a Japanese working population.

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Objectives-To ascertain the eVects of overtime and psychosocial job conditions on the occurrence of non-insulin dependent diabetes mellitus (NIDDM) in Japan. Design-An eight year prospective cohort study. Setting-An electrical company in Japan. Participants-In 1984, a mailed questionnaire was sent to industrial workers of an electrical company in Japan. After excluding those who had a history of diabetes mellitus or other chronic diseases, 2597 male respondents were prospectively followed up for the succeeding eight years. Data from 2194 (84%) who were completely followed up were analysed. The occurrence of NIDDM during the follow up period was assessed according to the WHO criteria on the basis of an annual screening programme. Main results-The age adjusted incidence of NIDDM was significantly higher in those who worked overtime more than 50 hours per month than in those who worked 25 hours or less per month (p<0.05). It was significantly higher in those who worked with new technology at baseline than in those who did not (p<0.05). Cox's proportional hazard model indicated that those who worked overtime more than 50 hours per month had 3.7 times higher risk of NIDDM after controlling for known risk factors (p<0.01) and those who worked with new technology had 2.4 times higher risk of NIDDM (p<0.05). Conclusions-It is suggested that longer overtime and use of new technology are risk factors of NIDDM in Japanese men.

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We recently purified to near homogeneity a novel type of regulatory protein for smg p25A, a ras p21-like GTP-binding protein, from bovine brain cytosol. This regulatory protein, named smg p25A GDP dissociation inhibitor (GDI), regulates the GDP-GTP exchange reaction of smg p25A by inhibiting dissociation of GDP from and subsequent binding of GTP to it. In the present studies, we isolated and sequenced the cDNA of smg p25A GDI from a bovine brain cDNA library by using an oligonucleotide probe designed from the partial amino acid sequence of purified smg p25A GDI. The cDNA has an open reading frame that encodes a protein of 447 amino acids with a calculated Mr of 50,565. This Mr is similar to those of the purified smg p25A GDI estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultracentrifugation, which are about 54,000 and 65,000, respectively. The isolated cDNA is expressed in Escherichia coli, and the encoded protein exhibits GDI activity. smg p25A GDI is hydrophilic overall, except for one hydrophobic region near the N terminus. smg p25A GDI shares low amino acid sequence homology with the Saccharomyces cerevisiae CDC25-encoded protein, which has been suggested to serve as a factor that regulates the GDP-GTP exchange reaction of the yeast RAS2-encoded protein, but not with the fry subunits of GTP-binding proteins having an afry subunit structure, such as G. and Gi. The smg p25A GDI mRNA was present in various tissues, including not only tissues in which smg p25A was detectable but also tissues in which it was not detectable. This fact has raised the possibility that smg p25A GDI interacts with another G protein in tissues in which smg p25A is absent. smg p25A was first purified from bovine brain membranes and has been characterized (11). The primary structure of smg p25A has been determined on the basis of the nucleotide sequence of its cDNA (16). The physical and kinetic properties of smg p25A indicate that this protein is a member of a superfamily of ras p21-ras p21-like GTP-binding proteins (G proteins) (for reviews, see references 1 and 27). The counterpart of smg p25A in rats has been reported to be the rab3-encoded protein (34). Although the functions of this G protein have not been clarified, it has been shown that the smg p25A gene is highly expressed in nerve tissues (21,23) and that its mRNA level is increased markedly after differentiation of PC12 cells into neuronlike cells by nerve growth factor or dibutyryl cyclic AMP (23). Our recent immunocytochemical studies have revealed that smg p25A is found not only in neuronal cells and adrenal glands but also in other secretory cells, such as endocrine and/or exocrine cells of the pancreas, parotid gland, and pituitary gland (17; A. Mizoguchi, S. Kim, T. Ueda, A. Kikuchi, H. Yorifuji, N. Hirokawa, and Y. Takai, J. Biol. Chem., in press). Moreover, our results indicate that in brain tissue, smg p25A is found mostly in presynapses, where it is localized mainly in synaptic plasma membranes and partly in synap...

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A cross-sectional study on 6,676 workers consisting of 4,243 males and 2,433 females aged 20-58 yr in a metal product factory was conducted to elucidate the relationship between work characteristics, e.g. job demand/control/support, sedentary job, overtime work and shift work, and waist to hip ratio (WHR) as well as body mass index (BMI) taking alcohol consumption, smoking, exercise and other psychosocial factors such as education and marital status into account. By a stepwise multiple regression analysis, BMI was associated with shift work, marital status and sedentary job for males, and with exercise but inversely associated with education for females. WHR was also associated with shift work, alcohol consumption, marital status and sedentary job but inversely associated with exercise for males, and with sedentary job, marital status and education but inversely associated with smoking for females. These results suggest that work characteristics such as sedentary job and shift work should also be considered when trying to prevent increases in BMI and WHR.