The association between annually-repeated health screening and health behavior among company employees

Although several studies have been undertaken to evaluate the efficacy of health screening in causing changes in health-related behavior, there are few findings with respect to the efficacy of annually repeated health screening.Using cross-sectional data drawn from a population consisting of white-collar workers in Osaka, Japan, the relation between the results of annually repeated health screening and individual health behavior was examined.Several diseases were related to diet and alcohol consumption, but not to physical exercise habits. High γ-GTP or alcoholic liver damage and hypertension were related to moderate alcohol consumption (p<0.001 and 0.05). A high cholesterol level was related to a nutritionally balanced diet (p<0.05). However, there were no diseases related to increased physical exercise.Findings in the present study, in combination with the literature indicate the possibility that annually repeated health screening intervention has been effective in promoting positive lifestyle changes in diet and alcohol consumption among participants. However, to conclusively evaluate the effucacy of the annually repeated health screening, further study is necessary.

A signal detection approach to the combined effects of work stressors on alcohol consumption

OBJECTIVE

To test the relationship between work stress and alcohol consumption and the efficacy of signal detection analysis in a work stress-alcohol consumption study.

METHOD

The study was part of a Work Site Health Project, which included a stress reduction program, at a manufacturing company in Osaka, Japan. The study design was a cross-sectional survey. The participants were Japanese male whitecollar workers (N = 457; 30 to 50 years old) in the head administrative office of a large manufacturing company. Measurements consisted of demographic variables of the workers (age, marital status, manner of living and Type A personality), work stress measures, working hours and alcohol consumption.

RESULTS

Of eight independent variables, six significant predictors of heavy alcohol consumption were identified in the first signal detection analysis. Of these six variables, job demand and skill discretion were work-stress-related measures. In the second multiple regression analysis, skill discretion and job demand were significant predictors of alcohol consumption among the workers in two of the seven subgroups categorized by the first signal detection analysis.

CONCLUSIONS

It was revealed that work stress did relate to alcohol consumption. However, the effect of the work stress upon alcohol consumption was limited to specific types of workers with multiple specific attributes. It was also inferred that the signal detection approach is an effective approach to the work stress alcohol consumption relationship.

Characteristics of health counselling in the workplace via e-mail

This study was conducted to examine how health counselling via electronic mail (e-mail health counselling) was used in the workplace. The definition of health counselling employed in this study was 'any assistance to an individual seeking to solve any health problem'. A total of 2119 health counsellings conducted at a Japanese company's head office (700 employees) in 1997 and 1998 was used for the analysis, which compared four health counselling methods: e-mail, face-to-face, telephone and ordinary mail. This study distinguished four main characteristics of e-mail health counselling. First, the most and second most frequently used counselling methods were face-to-face and telephone counselling, at 70 and 15%, respectively, with e-mail health counselling ranked third at 13%. e-mail counselling was the second most frequently used method for employees in their 20s and 30s, while it ranked third among those over 40. Only 6% of employees in their 50s used e-mail counselling. Secondly, the proportion of mental health issues treated via e-mail counselling was significantly higher, at 26%, than for other counselling methods, which was at or below 10% for each of the other methods. Thirty-two per cent of all mental health counselling was conducted via e-mail. Thirdly, compared with face-to-face counselling, e-mail counselling dealt with more health issues related to primary prevention than with those related to secondary or tertiary prevention. Fourthly, compared with face-to-face counselling, e-mail counselling dealt more with health issues of third parties. These results suggest that e-mail health counselling may be useful in reaching people other than those targeted by the remaining counselling methods.

The number of steps taken by flight attendants during international long-haul flights

BACKGROUND

Previous studies have revealed that female cabin attendants on long flights are most likely to have health problems. Since health problems can be related to workload and work stress and since the number of steps taken by an employee during a work shift can be an objective measure of the work load of cabin attendants, it is necessary to evaluate the predictors of the number of steps.

METHODS

We used pedometers worn by 118 female flight attendants to study the number of steps during flights and its predictors during long international flights.

RESULTS

The mean number of steps during 636.53 (SD = 129.11 )-minute flights was 10,742.85 (SD = 3,547.17). The crude number of steps per minute was 16.88, and the adjusted number of steps per minute was 14.04. Flight length and the number of sleeping hours worked (i.e., between midnight and 6:00 am) were significant predictors of the number of steps.

CONCLUSION

Although it is implied that flight duration and night flight increase the work load of flight attendants, we need to consider psychological aspects to evaluate the overall effects of their jobs on work stress and health.

Work stressors and alcohol consumption among white-collar workers: a signal detection approach

OBJECTIVE

Previous findings regarding the relationship between work stress and alcohol consumption are inconsistent and inconclusive. One of the primary reasons for the inconsistency of the findings is that simple models, such as multiple regression analysis or analysis of variance (ANOVA), have been conventionally adopted in studies examining the relationship between work stressors and alcohol consumption. Since higher order interactions of multiple work stressors, which lead to heavy alcohol consumption, might not be fully uncovered within the framework of a multiple regression analysis or ANOVA, another approach to exploring the interactions of work stressors is presented in this study.

METHOD

A signal detection analysis method was used to evaluate higher order interactions of work stress variables and to obtain basic information on 465 Japanese male white-collar workers.

RESULTS

Of 11 work stressor or work position variables, four significant predictors of heavy alcohol consumption were identified.

CONCLUSIONS

Two procedures were successfully performed in this study: (1) evaluating several higher order interactions of work stressors associated with heavy alcohol consumption, and (2) obtaining basic information to permit dividing the subjects into subgroups for further analysis using models and independent variables unique to each subgroup.

Work stressors, drinking with colleagues after work, and job satisfaction among white-collar workers in Japan

Although previous studies have examined the buffering effects of social support and coping style on the relationship between stress and alcohol consumption, they have typically relied on analysis of variance (ANOVA) or regression analysis. In addition, few studies have examined the potential stress-buffering effects of drinking with coworkers after work on the relationship between job stress and job dissatisfaction. In the present study, using a signal detection analysis, we evaluated the interactions of drinking with coworkers after work and work-stressor variables among Japanese white-collar workers (n = 397) in 1997. The analysis was performed for two groups of subjects divided based on their status in the company. This was necessary because in Japan the obligations to drink socially increase with one's rising status in the company. In both the "staff members and lower-level managers" and "middle-level and higher-level managers' groups, an interaction between work-stressor variables and drinking variables was observed. The findings imply that drinking with coworkers after work ameliorated the sense of job dissatisfaction, but only among those subjects who already had lower levels of work stressors. For subjects with high levels of work stressors, attitudes toward drinking with coworkers were unrelated to job satisfaction levels.

An inquiry into the causal relationship among leisure vacation, depression, and absence from work

Depression is one of the most prevalent psychological health problems in occupational settings. Through literature review and the experience of previous investigations, it is now presumed that depression could mediate the association between workload and absence from work. In order to examine the above relationship, a follow-up investigation was conducted using male white-collar employees. The authors have been examining the association between work-related factors and employee health for some years, and vacation has become recognized as one of the important candidates for alleviating psychological problems in the workplace. In July 1996, the chance of leisure vacations within the past year and the presence of depression were examined by a self-administrated questionnaire. The subjects were followed-up for the rest of the year and absence from work was monitored. By analyzing 357 eligible subjects aged 20-59 years, the causal association between leisure vacation, depression, and absence from work was examined. Through correlation and log-linear analysis, the following findings were explored: The decrease of leisure vacation chances was correlated with the presence of depression, and depression contributed to an increase in the absence from work after adjustment was made for possible confounding factors. Leisure vacation could be independent of other work-related factors such as working hours, and it seemed to be significant to investigate positive effects of leisure vacation on psychological well-being in the workplace.

Quality of life domains in the healthy public: A trial investigation using attendants for an annual health checkup

A trial investigation of subjects gathered for annual health checkups was performed to detect domains of quality of life in the healthy public, and to explore the changes of their demographic characteristics for the possibility of engaging them in health service activities in the community. The eligible 1,096 subjects aged 30-79 years were investigated. The period of this survey was from September to December, 1997. The subjects were questioned using ten quality of life domains which were preliminarily prepared and had been assumed to be most important in the subjects' lives in relation to the order of priority, importance, and satisfaction levels. The first most important domain in both the male and female subjects' lives was personal health, followed by relationships with family, though the mean importance scores for their personal health and relationships with family were almost equivalent. The mean scores for work abruptly decreased in males over 60 years of age. Also, the first large and the second relatively small principal components were extracted through principal components analysis. The proposed ten domains of quality of life are most likely valid and reliable in terms of the results analyzed and the comparison with a referred study. Relationships with family is an effective cue for health service activities in the community, and the significance of work on quality of life in the healthy public will have to be taken into account separately, especially in males.

CTLA4IgG treatment induces long-term acceptance of rat small bowel allografts

BACKGROUND

CTLA4 immunoglobulin (Ig)G that binds to B7 effectively inhibits the signaling of CD28/CTLA4-B7 pathway and induces antigen specific T cell unresponsiveness in vitro and in vivo. Using CTLA4IgG, we examined induction of long-term graft survival and the mechanism of maintenance of tolerance in rat allogeneic small bowel transplantation.

METHODS

Small bowels of Brown-Norway rats (RT1n) were heterotopically transplanted into Lewis rats (RT1l). Recipients were treated with an i.p. injection of either CTLA4IgG or control IgG for 7 days.

RESULTS

Long-term survival was observed in rats treated with CTLA4IgG, whereas control rats died within 16 days after transplantation. To examine whether a tolerant state was established in long-term survival rats, secondary transplantation was performed using small bowels of Brown-Norway rats or ACI (RT1b) rats. It was demonstrated that small bowels of Brown-Norway rats were accepted; however, those of ACI rats were rejected within 10 days. Serum concentrations of interleukin (IL)-4 were maintained at >50 microg/ml for 7 days after transplantation in rats treated with CTLA4IgG but <15 microg/ml in control rats. IL-2 concentration was reduced to half in CTLA4IgG-treated rats compared with that in control recipients. Serum IFN-gamma in CTLA4IgG-treated recipients increased after transplantation and was not distinguishable from that of control recipients during the first 7 days after transplantation. Conclusion. We demonstrated that CTLA4IgG treatment alone for 7 days induced a long-term donor specific tolerance in rat allogeneic small bowel transplantation. The induction of long-term acceptance of small bowel allografts by CTLA4IgG is not caused by simply the shift of anti-alloimmune responses from Thl to Th2 cytokine production.

Surgical treatment for recurrent tumors of primary malignant melanoma of the esophagus: a case report and review of the literature

The purpose of this communication is to present a case of resection performed for local recurrent tumors of primary malignant melanoma of the esophagus (PMME) and to review the relevant literature. The patient was a 54 year-old man who had received an intraabdominal esophagectomy with a total gastrectomy for primary malignant melanoma of the abdominal esophagus in another hospital, in November 1995. After the initial operation, he was treated as an outpatient. In August 1997, computed tomography and ultrasonography revealed recurrent tumors in the dorsal pancreatic lymph node and in the right adrenal gland. The recurrent tumor of the dorsal pancreas directly invaded the dorsal pancreas parenchyma and occluded the superior mesenteric vein and splenic vein, and the other metastatic tumor in the right adrenal gland existed in the absence of circumference invasion. Metastases of the PMME were confirmed in the dorsal pancreas, the superior mesenteric vein, splenic vein, and right adrenal gland, and were removed by a total pancreatectomy on October 7, 1997. By immunohistochemical staining, we found that the focal areas expressed S-100 protein and HMB-45 antibody. Currently (February 1998), the patient is alive and disease-free. PMME is an extremely rare tumor with a poor prognosis for survival. Only 2 cases of removal of recurrent tumors, including the present case, have been reported. The treatment of choice is surgical resection, even in cases of recurrence, because radiotherapy and/or chemotherapy have not been proven to be beneficial; however, they may play a palliative role if surgery is not possible.

Prevention of small intestinal ischemia-reperfusion injury in rat by anti-cytokine-induced neutrophil chemoattractant monoclonal antibody

The function of cytokine-induced neutrophil chemoattractant (CINC), which is the rat counterpart to human growth-related gene product belonging to the CXC chemokine subgroup, is based principally on neutrophil-specific chemotactic activity. In addition, we previously reported that plasma CINC was elevated during the period of small intestinal ischemia-reperfusion injury, and that there was a correlation between the degree of mucosal damage and the peak level of CINC after reperfusion, suggesting that CINC may play a major role in neutrophil infiltration into the rat small intestinal ischemia-reperfusion injury site. Thus, we investigated whether administration of anti-CINC monoclonal antibodies (mAbs) reduces small intestinal ischemia-reperfusion injury. Small intestine was subjected to ischemia for 3 h by occlusion of the anterior mesenteric artery with an atraumatic vascular clump. After infusion of anti-CINC mAbs or isotype-matched mAbs, the intestine was subjected to reperfusion. The pretreatment with anti-CINC mAbs attenuated ischemia-reperfusion injury in the small intestine, in association with the reduction of tumor necrosis factor-alpha and myeloperoxidase production, and resulted in the prolongation of survival. It is concluded that CINC plays an important role in the onset of rat small intestinal ischemia-reperfusion injury. In addition, blocking the action of CINC, namely, the neutrophil chemotactic activity, may be useful in preventing ischemia-reperfusion injury in the small intestine.

The plasma FK506-binding protein 12 level is related to acute cellular rejection in small bowel transplantation

Since FK506 binding protein (FKBP12) inhibits dose-dependently the immunosuppressive activity of FK506 in vitro, plasma FKBP12 levels were measured after rat small bowel transplantation (SBTx). The mean plasma FKBP12 level in untreated recipients increased significantly at the onset of acute cellular rejection (ACR) compared to that in FK506-treated recipients without rejection at the same time after SBTx (P < 0.05). In both groups, however, the mean plasma FKBP12 level did not increase at 1 day after SBTx. These results suggest that plasma FKBP levels may be affected by ACR, but not by ischemia-reperfusion injury. Therefore, the plasma FKBP12 level should be considered as one of the parameters related to the immunosuppressive activity of FK506 in SBTx.

Downregulation of cytokine-induced neutrophil chemoattractant and prolongation of rat liver allograft survival by interleukin-10

We investigated whether the administration of recombinant human interleukin-10 (rhIL-10) regulates the production of cytokine-induced neutrophil chemoattractant (CINC) and improves graft survival in rat orthotopic liver transplantation (OLTx). Allograft recipients received injections of rhIL-10 at doses of 2, 10, 20, or 50 micrograms/kg/day. The allograft recipients that received rhIL-10 at 10 or 20 micrograms/kg/day showed a slight but significant prolongation of graft survival to 13.0 +/- 0.4 and 13.8 +/- 0.3 days, respectively, compared with 9.6 +/- 0.2 days in untreated allografts. Conversely, the administration of high-dose rhIL-10 shortened the allograft survival. In the rhIL-10 treatment groups, the mean serum and tissue levels of CINC at every time point after OLTx were reduced significantly compared with those in the no-treatment group. The mean peak neutrophil counts in the peripheral circulation (PC) of the groups given rhIL-10 at 10, 20, or 50 micrograms/kg/day from the samples obtained 12h after reperfusion were decreased significantly compared with the no-treatment group. Furthermore, the mean peak neutrophil counts in the PC of the groups given rhIL-10 at 10 or 20 micrograms/kg/day from the samples obtained between postoperative days (PODs) 7 and 10 were decreased significantly compared with the no-treatment group. The magnitude of liver damage and leukocyte infiltration in the rhIL-10-treated allografts on PODs 1 and 7 was reduced compared with that of untreated allografts. Our data indicate that the administration of rhIL-10 downregulates CINC production during the period of reperfusion injury and acute cellular rejection after OLTx, and prolongs liver allograft survival, suggesting that IL-10 therapy is potentially beneficial in OLTx.

An investigation into the effects of vacations on the health status in male white-collar workers

There are many stress factors in occupational settings, and the lack of vacations could be one of factors in the context of work stress. The authors have been studying the relationship between workload and employee health. This time, an investigation into the effects of leisure vacations on worker health status using male white-collar employees aged 20-60 years engaged in a manufacturing company was conducted. The subjects were questioned on work stress factors including vacations and modifiers in their occupational settings, and on psychological and physiological stress reactions; that is, how often they were able to take leisure vacations every year, their average working hours a day and work stress factors from the Demand-Control-Support model. The questions also examined other factors concerning the employees such as type-A behavior and lifestyles as modifiers, diseases of the employees, physical complaints, feelings about sleep, perceived stress, job and life satisfaction, and stress reactions as measured by physiological examination. Correlation and logistic regression analysis were conducted with the 551 eligible subjects. The results were as follows: Leisure vacation was decreasingly related to some of psychological stress reactions after adjustment was made for working hours and for modifiers. Less vacation was increasingly related to the workers' diseases especially among the employees aged 20-34, though the association was not statistically significant. Vacations did not show obvious association with physiological measures. These findings demonstrate the effectiveness and possibility of leisure vacation in controlling fatigue and maintaining the health of workers. Vacation should always be taken into consideration as a stress factor in a survey of the health problems of white-collar workers.

Mortality and work conditions: a retrospective follow-up assessment of the effects of work conditions on the mortality of male employees in the manufacturing industry

A retrospective follow-up study was conducted to investigate the effects of work conditions on mortality. Mortality rates among male employees aged 40-60 years in the Japanese steel industry were calculated for separate work condition factors, such as job site location (parent company or subsidiary company), job category (white-collar or blue-collar) and work schedule (day work or shift work). Odds ratios were calculated to evaluate the independent effects of work condition factors on mortality using a logistic regression method. Death certificates and demographic statistics, 1991-1995, from the annual personnel reports of the employees which had been compiled and preserved by the company, were utilized. There were 19,642 employees in April, 1991, and 171 deaths and 76,761.7 person-years were observed. No work condition factors were associated with the mortality rates. Selection bias was speculated from the findings. Since there is a thorough medical checkup system at this company, the employees identified with serious health problems would probably already have been excluded as potential candidates for transferring to subsidiaries or for work schedule changes. These findings and the interpretation were consistent with those of other reports which have been conducted in Japanese industrial fields. Mortality was not an appropriate indicator for assessing health risks in the occupational environment, but it reflects the real status of health care management. Through careful interpretation it has been suggested that there is a possibility that past health care work conditions activity can be accessed.

RECENT LIQUID CRYSTAL MATERIAL DEVELOPMENT FOR ACTIVE MATRIX DISPLAYS

▪ Abstract  The structural dependence of the optical and dielectric physical properties of liquid crystal (LC) materials is investigated with the aid of molecular modeling. A material characterization of LC materials is made using fundamental physical measurement values, e.g. optical, dielectric, elastic, and viscous parameters. A novel mixture design based on selected LC materials leads to significant improvements that fulfill the requirements for active matrix LC displays, for instance, fast switching times, lower power consumption, and wide operation temperature ranges. The development of LC displays from the material supplier's point of view is briefly reviewed.

Early detection of graft function using hepatic venous oxygen saturation in pig liver transplantation

In this study, we measured hepatic venous oxygen saturation (Shvo2) in pig liver transplantations in order to evaluate its usefulness as a predictor of early postoperative graft function. Shov2 of the grafts with good function was over 60% after reperfusion, and the mean Shov2 at end of the operations was 69.8+/-6.9%. Shov2 of the grafts with poor function never increased over 60%, and for most of the operation until its end, Shov2 was under 50%. At the end of the operations, the mean Shov2 was 39.7+/-5.5%. Shov2 levels of the grafts with good function were significantly higher than those of the grafts with poor function (P=0.0016). Corresponding with these Shov2 data, glutamic-oxaloacetic transaminase and lactate dehydrogenase levels of grafts with poor function were significantly higher than those of the grafts with good function. Shov2 represents a summation of the hemoglobin oxygen saturation at the venous end of the sinusoids of the liver and indicates adequate hepatic blood flow if the hepatic oxygen is constant. A decrease of Shov2 in poor graft function might indicate a disturbance of microcirculation in the sinusoids. Through the use of Shov2, we are able to recognize conditions of microcirculatory disturbance more quickly than with any other system. In conclusion, Shov2 is a useful indicator for an early and reliable prediction of outcome in liver transplantation.

Type A and Type B behaviors, work stressors, and social support at work

BACKGROUND

How Type A personality is related to the stress process has been investigated. However, in the occupational health field, stressful aspects of the work environment for Type A or B workers have not been fully revealed.

METHODS

In the present study, using signal detection analysis, we analyzed data concerning work stressors and social support (SS) at work among Japanese white-collar workers (n = 560) and identified the respective aspects of work that are stressful for Type A and B workers. We also evaluated the interactions of SS at work and stressor variables among Type A and B workers, individually.

RESULTS

Except for one significant predictor, i.e., being unable to learn new things at work, the significant predictors of mental stress were generally quite different for Type A and B workers. Specifically, SS from management was a cause of mental stress for certain groups of Type A workers.

CONCLUSIONS

It was revealed that the stressful aspects of work environment varied markedly in accord with the Type A vs Type B personality status of the subjects. The results also implied that even support from management can be stressful for Type A workers who had heavy workloads. The present study used specific measures sensitive to individual stressors and identified specific subgroups with the same work stressors. The findings provide information that is useful for stress reduction intervention.

[A survey of the inclinations of medical students towards becoming occupational physicians]

We conducted a survey to investigate medical students awareness of the activities of occupational physicians and their willingness to do postgraduate courses in this field. Those surveyed were fifth grade students in six universities in the Kinki district of Japan in 1993. In analyzing the responses of 368 eligible subjects, the response rate was 68.4% and the following results were obtained. 1) Only one of the 368 subjects expressed a desire to become an occupational physician after graduation, however 24.2% of those surveyed had considered becoming occupational physicians. More female students and, males over the age of 25, had considered becoming occupational physicians. Anxiety about a possible surplus of medical doctors in the near future was a factor that led them to consider becoming occupational physicians. 2) There were few negative responses concerning the activities of occupational physicians, even among those who had not considered becoming occupational physicians. 88.3% of those surveyed complained of a lack of information regarding postgraduate courses. 3) Responses were varied concerning conditions in the practice of occupational physicians. Those who had considered becoming occupational physicians were mostly concerned with the establishment of a system for the acceptance of occupational physicians in industry, while those who had not thought of becoming occupational physicians, considered practicing as occupational physicians as a sideline to regular clinic duties. 4) Having considered the above results and those of other researchers, we concluded that supplying more information related to the activities of occupational physicians and offering further postgraduate training programs in occupational medicine would encourage more medical students to become occupational physicians.

Functional interactions of gene 32, 41, and 59 proteins of bacteriophage T4

Genes 41 and 59 of bacteriophage T4 are involved in DNA recombination as well as in DNA replication. The 41 protein has a DNA helicase activity. The 59 protein has been recently purified and found to have a specific affinity for both 32 protein (single-stranded DNA-binding protein) and 41 protein (Yonesaki 1994, J. Biol. Chem. 269, 1284-1289). We examined the effects of 59 protein on ssDNA-dependent ATPase activity and DNA helicase activity of 41 protein in the presence or absence of 32 protein. The ATPase activity of 41 protein was strongly inhibited by 32 protein over a wide range of amounts from subsaturation to oversaturation of ssDNA. The 32 protein was also inhibitory toward DNA helicase activity. Addition of 59 protein effectively eliminated these inhibitory effects of 32 protein. Moreover, 59 protein facilitated 41 protein to overcome the barrier to initiate the unwinding reaction with a duplex flanking a single-stranded DNA gap. Intriguingly, 32 protein at an amount optimal for saturation of ssDNA stimulated the overcoming of the barrier when 59 protein was present. For the best circumvention of this initiation barrier, only eight monomers of 59 protein/one DNA substrate molecule containing 2900 nucleotides of ssDNA were required. These results strongly suggest that 59 protein modulates 41 protein activities by forming a complex with 41 protein and that 41 protein can produce recombinogenic ssDNA with the aid of 32 and 59 proteins.

An investigation of the effects of lifestyle on care-seeking behavior using data from health insurance claims

To clarify the effects of lifestyle on care-seeking behavior, we conducted a questionnaire survey using Morimoto's 8 lifestyle factors and tabulated the medical evaluations at annual medical checkup of 1212 male white-collar employees of a company (aged 21-60 years in 1991), and then extracted the health insurance data for these subjects for the first half of 1992 from the health insurance-carrier computer system. The percentage of employees who visited medical facilities, the number of days of medical care, and the medical fees reported on the health insurance claims were chosen as indices of care-seeking behavior, and the relationship of each index to lifestyle and medical checkup data was examined. The health practice index (HPI), which was obtained by summing the scores for the 8 lifestyle factors was associated with the medical evaluation as expected, but was inversely correlated with the indices of care-seeking behavior. The percentage of employees who visited medical facilities, the number of the days of medical care, and the total medical fees were all higher for the subjects with high HPI scores than for those with low HPIs. Our findings are consistent with those of other researchers who have found an inverse relationship between tobacco smoking and health insurance claims, which has been attributed to the degree of consciousness of health. Compared to smokers, non-smokers have high consciousness of health and tend to consult a doctor more frequently, with resulting increased frequency of medical facility consultation and days of medical care, as well as medical fees. Lifestyle is an important aspect of physical and mental health status.(ABSTRACT TRUNCATED AT 250 WORDS)

An inquiry into the relationship between job strain and blood pressure in male white-collar workers

We conducted a cross-sectional study to investigate the relationship between psychological load and blood pressure using white-collar male employees of a company located in an urban area in June, 1991. Excluding those with diseases which might induce hypertension or those under 20 yr and over 60 yr of age, 570 male subjects were eligible for analysis. Logistic regression analysis was applied to 461 subjects excluding 109 who showed unstable blood pressure level; the dependent variable was blood pressure class which contained 386 normotensives and 75 hypertensives. The explanatory variables were age, obesity, alcohol intake, cigarette smoking, habitual physical exercise, all well-known factors affecting blood pressure level, working time, commuting time, paid annual leave, and type of living (with family or alone) as objective workload, and Karasek's job strain as psychological workload. Odds ratio of job strain was statistically significant after adjusting for the foregoing factors, but in the case of high job strain, the prevalence of hypertension was low. Theorell has pointed out that contrary to the usual recognition those having a family history of hypertension tended to have a non-complaining life attitude and this indication seems to be the reason for the results of this analysis. Blood pressure is one of the most important problems in the field of industrial health and because of our highly industrialized society, it is necessary to consider psychological workload. Longitudinal observations which take into account psychological workloads must be planned, and personal traits represented by a family history of hypertension should be always taken into consideration.

[An inquiry into the factors affecting the complaints of subjective symptoms in VDT operators]

In a study of VDT workers the relationship between 1) their general life condition and working environment and 2) their eye, shoulder, neck, arm, waist and back complaints and their psychological symptoms was investigated. The subjects of the study were (147 workers whose age ranged from 18 to 39 years, and who had used VDT for a monthly average of more than 40 h. The results were as follows: 1) For most of the symptoms, a tendency was observed for females to complain more than males and for younger workers to complain more than the older workers. Neck, shoulder, arm, waist and back complaints were more common than psychological symptoms. These physical complaints appeared to be the most common among VDT workers. 2) The occurrence of eye-related symptoms is related to items directly affecting sight. This reaffirms the importance of illumination for the visual system. 3) This investigation showed that a relatively good VDT working environment was secured for the subjects of the present study. It is important that consideration be given to labor management such as provision of rest period and supervision.

The "protocell": a mathematical model of self-maintenance

The concepts of self-generation, autonomous boundary and self-maintenance are explained briefly. The "protocell" is presented as a model of self-maintenance which is based on simple physical mechanisms of diffusion and reaction. The time evolution of the surface of the protocell is taken into account explicitly in the form of a Stefan condition giving rise to a non-linear feedback of the surface motion to the reaction and diffusion processes inside the protocell. The spatio-temporal dynamics are investigated, particularly in the neighbourhood of the stationary states, showing a self-maintaining behaviour under a certain range of nutritional conditions. Under another set of conditions we find an instability leading to a division process so that the population of protocells becomes self-maintaining instead of the single individual. The presented formulation of the protocell model is crucially improved compared with a previous version which required boundary conditions at infinity. The previous version was not strictly self-maintaining since dynamics outside the cell were essential for its behaviour.

Physico-chemical model of a protocell

A physico-chemical model of a self-maintaining unity or protocell is constructed on the basis of reaction and diffusion processes. The surface motion of the protocell is taken into account explicitly by a so-called Stefan condition, which leads to a nonlinear feedback to the reaction and diffusion processes. The spatio-temporal dynamics in the neighbourhood of the steady states is investigated in the framework of linear stability analysis with the use of an expansion in terms of spherical harmonics Ylm. It is shown that modes with l greater than or equal to 2 become successively unstable with increasing nutrient supply. The leading instability with l = 2 initiates a process of the nonlinear dynamics which is interpreted as the onset of division. A stabilizing effect of surface tension is also discussed.

Oscillating spatial structures of a tissue

We present a simple mathematical model for the self-controlled growth of a tissue giving rise to an oscillating tissue size under certain conditions. The control is brought about by two substances (two inhibitors or one inhibitor and one nutrient) which influence the cell kinetics locally. The inhibitors are produced by the tissue itself (whereas the nutrient comes from outside but is consumed by the tissue which produces the same effect). Both diffuse freely throughout the tissue, and thus realize a communication between different parts of the tissue. In any case the tissue approaches a self-maintaining space-time structure with properties depending on the parameters of proliferation, death and inhibiting control. We discuss the conditions for this structure not to be time-independent but oscillating.