Hirofumi Nagase

NATURAL KILLER (NK) CELL ACTIVITY AND NK CELL SUBSETS IN WORKERS WITH A TENDENCY OF BURNOUT

The involvement of cellular immunity in the burnout syndrome remains to be elucidated. We assessed three components of burnout of the Maslach Burnout Inventory: emotional exhaustion; depersonalization (DP); and personal accomplishment, as well as natural killer cell activity (NKCA) and NK cell subsets in 42 male workers. Workers with a higher DP score showed a lower NKCA and a lower proportionality of CD57+CD16+ to total lymphocytes. There were no differences in any of the health behaviors (e.g., smoking, alcohol, or obesity) between workers showing higher burnout and those showing lower burnout. A stepwise multiple regressions analysis demonstrated that NKCA was closely correlated with DP, independent of other variables, including a stress index. These results suggest that the relationship between reduced cellular immunity and DP is not due to traditional work stress or health behavioral problems. Further studies on DP as a psychosomatic disorder as well as an occupational health problem should be performed in the future.

Family History‐related Risk of Gastric Cancer in Japan: A Hospital‐based Case‐Control Study

In Japan, there have been a few reports on the familiar factors of gastric cancer (GC)and on the GC risk related to family history (FH) at other cancer sites. We analyzed the association between GC occurrence and a positive FH of cancer of the stomach and of other sites in a hospital‐based case‐control study. The subjects included cases histologically confirmed as incident cancer of the stomach (n=136; 86 male and 50 female patients) and sex and age (± 1 year)‐matched controls. GC risk was high when a subject had a parental history of GC [Mantel‐Haenszel odds ratio adjusted for sex and age (OR) =2.3; 95% confidence interval (95%CI):1.1–5.0]. GC risk was almost unity for a cancer FH of any other cancer site, even among closer relatives, suggesting little or no contribution to GC occurrence. The familial occurrence of GC found in this study suggests the existence of a genetic susceptibility to cancer of the stomach. Further, females tended to show higher GC risks than males, when reporting an affected mother (OR=6.0; 95%CI:1.1–31.4 and OR=1.4; 95%CI:0.4–4.8, respectively), whereas males showed a slightly higher risk than females when reporting an affected father (OR=2.4; 95%CI:0.8–7.5 and OR=2.3; 95%CI:0.4–15.6, respectively). This suggests a possible gender difference in how environmental factors influence GC occurrence. The development of gastric tumors seems to be due to a complex and unknown interaction between environmental and genetic factors.

Psychological Factors Including Sense of Coherence and Some Lifestyles are Related to General Health Questionnaire-12 (GHQ-12) in Elderly Workers in Japan

ObjectivesThe number of elderly workers has also been increasing and poor psychological well-being in elderly workers has been reported. The aim of this study is to elucidate the factors that are related to poor psychological well-being in elderly workers.MethodsWe administered General Health Questionnaire-12 (GHQ-12) as an indicator of psychological well-being to 330 male elderly workers in the age range of 50–69, and analyzed different psychological factors, namely sense of coherence (SOC), and physical and lifestyle variables such as blood pressure, serum total cholesterol, smoking frequency, alcohol intake, exercise frequency, and body mass index (BMI) that are related to GHQ-12.ResultsWhen the cut-off point of GHQ-12 was 2/3, 97 workers who showed high GHQ-12 score were classified as one group having poor psychological well-being. A statistically significantly lower SOC score, higher stress score, lower frequency of exercise, higher smoking score and higher BMI, but not longer working hours or higher shift work score in the workers with higher GHQ-12 scores were observed than in the workers with normal GHQ-12 scores. Multiple logistic regression analysis showed that the low SCO score, low frequency of exercise, high smoking frequency and high BMI significantly contributed to the high GHQ-12 score.ConclusionsA low SOC score in elderly workers is assumed to be directly related to poor psychological well-being, or via the development of lifestyle problems such as lack of exercise, obesity, and smoking in elderly workers. This assumption must be confirmed by conducting future intervention studies on lifestyle.

Inhibitory effect of pregnancy on stress-induced immunosuppression through corticotropin releasing hormone (CRH) and dopaminergic systems

To clarify the involvement of pregnancy in the response of the neuroendocrine-immune system to stress, we examined splenic natural killer-cell-activity-(NKCA) and its relevant central and blood parameters in female virgin and pregnant rats (10 to 11 days gestation) exposed to forced water-immersion stress with durations of 90 min and 180 min. Decreases in splenic NKCA, corticotropin releasing hormone (CRH) in the hypothalamus, and increases in progesterone (P), beta-endorphin (beta EP), and dopamine (DA) metabolic ratios in the frontal cortex and nucleus accumbens produced by stress were recognized in the virgin rats, but not in the pregnant rats. Pregnancy reduced splenic NKCA in rats without stress, but elevated it in the rats exposed to stress with a duration of 180 min. These findings suggest inhibitory effects of pregnancy on stress-induced immunosuppression and neuroendocrine changes, thereby promoting homeostasis in the neuroendocrine-immune system against stress. Such enhanced homeostasis associated with pregnancy seemed to be mediated by the activation of placental P and placental or pituitary beta EP in cooperation with mesocortical and mesolimbic DA systems and hypothalamic CRH.

Enhancement of a Sense of Coherence and Natural Killer Cell Activity which Occurred in Subjects who Improved their Exercise Habits through Health Education in the Workplace

Enhancement of a Sense of Coherence and Natural Killer Cell Activity which Occurred in Subjects who Improved their Exercise Habits through Health Education in the Workplace: Hiroyuki Nakamura, et al. Department of Environmental and Preventive Medicine, Graduate School of Medical Science, Kanazawa University— We have previously demonstrated that a sense of coherence (SOC), a candidate for a mediating stress factor, is involved in natural killer cell activity (NKCA) reduced in smokers, whereas the relationship among exercise, NKCA and SOC is unclear. To clarify the effects of exercise on SOC and NKCA, we examined the changes in SOC and NKCA before and after health education to encourage exercise. Of one‐hundred and one male office workers who received the health education for one year, 27 improved, 65 were unchanged and 9 had deteriorated exercise habits. The repeated measures analysis of variance showed that SOC in workers with improvement in the exercise habit were increased more significantly by the health education than those in workers without improvement (p<0.05). Although the change in NKCA produced by health education was recognized to be significantly different in those who had never smoked from that in current smokers (p<0.05), multiple regression analysis demonstrated that improvement in health practice significantly contributed to increases in both SOC (p<0.01) and NKCA (p<0.05) in never smokers, independently of other psychological factors. These results suggest that subjects with improvement in exercise enhance NKCA through increased SOC in never smokers.

Effects of exposure to microwaves on cellular immunity and placental steroids in pregnant rats.

OBJECTIVES: Microwaves produce various detrimental changes based on actions of heat or non-specific stress, although the effects of microwaves on pregnant organisms has not been uniform. This study was designed to clarify the effect of exposure to microwaves during pregnancy on endocrine and immune functions. METHODS: Natural killer cell activity and natural killer cell subsets in the spleen were measured, as well as some endocrine indicators in blood--corticosterone and adrenocorticotrophic hormone (ACTH) as indices of the hypothalamic-pituitary-adrenal axis--beta-endorphin, oestradiol, and progesterone in six female virgin rats and six pregnant rats (nine to 11 days gestation) exposed to microwaves at 10 mW/cm2 incident power density at 2450 MHz for 90 minutes. The same measurements were performed in control rats (six virgin and six pregnant rats). RESULTS: Skin temperature in virgin and pregnant rats increased immediately after exposure to microwaves. Although splenic activity of natural killer cells and any of the subset populations identified by the monoclonal antibodies CD16 and CD57 did not differ in virgin rats with or without exposure to microwaves, pregnant rats exposed to microwaves showed a significant reduction of splenic activity of natural killer cells and CD16+CD57-. Although corticosterone and ACTH increased, and oestradiol decreased in exposed virgin and pregnant rats, microwaves produced significant increases in beta-endorphin and progesterone only in pregnant rats. CONCLUSIONS: Microwaves at the power of 10 mW/cm2 produced activation of the hypothalamic-pituitary-adrenal axis and increased oestradiol in both virgin and pregnant rats, suggesting that microwaves greatly stress pregnant organisms. These findings in pregnant rats suggest that--with exposure to microwaves--pregnancy induces immunosuppression, which could result in successful maintainance of pregnancy. This enhancement of adaptability to heat stress with pregnancy may be mediated by activation of placental progesterone and placental or pituitary beta-endorphin.

Change in digital blood flow with simultaneous reduction in plasma endothelin induced by hand-arm vibration

Involvement of endothelium-derived relaxing factor (EDRF) or endothelium-derived constricting factor (EDCF) has been proposed as the pathophysiologic mechanism of vibration-induced white finger (VWF). Recent evidence that endothelin is a potent vasoconstrictor peptide indicates that it may play a role in vasoregulation during vibration exposure through the local actions of EDRF or EDCF. Therefore, we examined the effects of grasping (50 N) and hand-arm vibration (50 m/s2 rms, 120 Hz, x-axis) on digital blood flow (DBF) and on the level of plasma endothelin in seven healthy male office workers. Grasping decreased DBF without affecting endothelin, and vibration increased DBF with a simultaneous reduction in endothelin. The grasping-induced decrease in DBF seemed to be due to mechanical compression of the vessels. The negative correlation between DBF and endothelin during vibration exposure suggests that a reduction in release of endothelin from smooth muscle into the vessel cavity during vibration leads to vasodilatation, possibly attributable to the local axon reflex.

Changes of cerebral vasoactive intestinal polypeptide- and somatostatin-like immunoreactivity induced by noise and whole-body vibration in the rat

To clarify the role of vasoactive intestinal polypeptide (VIP) and somatostatin, somatropin-release inhibiting factor, (SRIF) neurons in the response to organisms to noise or whole-body vibration stress, VIP and SRIF-like immunoreactivity were determined in various regions of the rat brain following exposure for 90 min to noise (broad band, 102 dB) or whole-body vibration (20 Hz, 4.0 g). Both noise and whole-body vibration significantly increased VIP-like immunoreactivity in the amygdala. A significant reduction of VIP like immunoreactivity in the hippocampus was induced only by whole-body vibration. On the other hand SRIF-like immunoreactivity was decreased significantly in the hypothalamus and increased significantly in the amygdala by noise and whole-body vibration, respectively. The present findings would seem to indicate that the amygdalofugal VIP neural system is involved in regulating hypothalamic and pituitary hormone secretions in non-specific reactions to stress. Responses of hippocampal VIP and the amygdalofugal SRIF to whole-body vibration stress are assumed to be activated as specific reactions to the stress.

Natural Killer Cell Activity and its Related Psychological Factor, Sense of Coherence in Male Smokers

Natural Killer Cell Activity and its Related Psychological Factor, Sense of Coherence in Male Smokers: Hiroyuki Nakamura, et al. Department of Environmental and Preventive Medicine, Graduate School of Medical Science, Kanazawa University—Sense of Coherence (SOC), a candidate for a mediating stress factor, is studied in the framework of Antonovskys salutogenesis paradigm, which emphasizes the origin of health. Emotional stress is associated with a decrease in cellular immune function including natural killer cell activity (NKCA). The purpose of this study was to clarify the involvement of SOC and smoking behavior in cellular immunity including NKCA. The author performed a psychological questionnaire and examined NKCA and NK cell subsets in 125 men (45.1 ± 7.88 yr, mean ± SD) engaged in office work. The psychosocial factors included SOC and health locus of control (HLC) as well as perceived life stress and life style. SOC and smoking status was recognized to affect NKCA as well as CD57+CD16+. A higher SOC and never smoking significantly contributed to a higher level of NKCA. In subjects with a higher SOC, NKCA in never and ex‐smokers were significantly higher than those in present smokers, whereas in subjects with a lower SOC, NKCA only in never smokers was significantly higher than that in present smokers. There were no significant differences in the stress index, alcohol obesity, or HLC among smoking status. SOC showed a moderately negative relationship with life stress. Multiple regression analysis demonstrated that SOC and smoking were significantly correlated to NKCA and CD57+CD16+, independently of other psychosocial variables, suggesting salutogenic contributions of SOC. SOC may be an important psychological modifier in determining the relationship between cellular immunity and smoking cessation. The reduced NKCA with lower SOC in present smokers, whose association seems to be produced not through daily life stress, must be dealt with as an occupational mental health problem.

Uteroplacental circulatory disturbance mediated by prostaglandin F2α in rats exposed to microwaves

Abstract To clarify the effects of microwaves on pregnancy, uterine or uteroplacental blood flow and endocrine and biochemical mediators, including corticosterone, estradiol, prostaglandin E 2 (PGE 2 ), and prostaglandin F 2 α (PGF 2 α), were measured in rats exposed to continuous-wave (CW) microwave at 2 mW/cm 2 incident power density at 2450 MHz for 90 min. Colonic temperature in virgin and pregnant rats was not significantly altered by microwave treatment. Microwaves decreased uteroplacental blood flow and increased progesterone and PGF 2 α in pregnant, but not in virgin rats. Intraperitoneal (i.p.) administration of angiotensin II, a uteroplacental vasodilator, before microwave exposure prevented the reduction in uteroplacental blood flow and the increased progesterone and PGF 2 α in pregnant rats. Increased corticosterone and decreased estradiol during microwave exposure were observed independent of pregnancy and pretreatment with angiotensin II. These results suggest that microwaves (CW, 2 mW/cm 2 , 2450 MHz) produce uteroplacental circulatory disturbances and ovarian and placental dysfunction during pregnancy, probably through nonthermal actions. The uteroplacental disturbances appear to be due to actions of PGF 2 α and may pose some risk for pregnancy.