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Naoki Nakaya

Publications and source records attributed to Naoki Nakaya.

34 records · Page 2Linked to original sources
PubMed2004

Cigarette smoking and the risk of gastric cancer: a pooled analysis of two prospective studies in Japan.

To examine the association between cigarette smoking and the risk of gastric cancer, we conducted a pooled analysis of 2 population-based prospective cohort studies in rural northern Japan. Cohort 1 included 9,980 men (>or=40 years old) and Cohort 2 included 19,412 men (40-64 years old). The subjects completed a self-administered questionnaire on cigarette smoking and other health habits. We identified 228 cases of gastric cancer among Cohort 1 subjects (9 years of follow-up with 74,073 person-years) and 223 among Cohort 2 subjects (7 years of follow-up with 141,675 person-years). From each cohort, we computed the relative risk (RR) and 95% confidence interval (CI) of gastric cancer associated with smoking using a Cox regression analysis and pooled these estimates to obtain summary measures. The pooled multivariate RRs (95% CIs) for current smokers and past smokers compared to subjects who had never smoked were 1.84 (1.39-2.43) and 1.77 (1.29-2.43), respectively. The higher number of cigarettes smoked per day among current smokers was associated with a linear increase in risk (trend p < 0.05). The significant increase in risk for past smokers remained for up to 14 years after cessation. An increased risk was noted for cancer of the antrum but not for cardia or body lesions. The risk was increased for both differentiated and nondifferentiated histologic subtypes. Our findings support the hypothesis that cigarette smoking is a risk factor for gastric cancer.

Adult↗
PubMed2004

Nitric oxide is a regulator of hematopoietic stem cell activity.

Hematopoietic stem cells give rise to various multipotent progenitor populations, which expand in response to cytokines and which ultimately generate all of the elements of the blood. Here we show that it is possible to increase the number of stem and progenitor cells in the bone marrow (BM) by suppressing the activity of NO synthases (NOS). Exposure of mice to NOS inhibitors, either directly or after irradiation and BM transplantation, increases the number of stem cells in the BM. In the transplantation model, this increase is followed by a transient increase in the number of neutrophils in the peripheral blood. Thus, our results indicate that NO is important for the control of hematopoietic stem cells in the BM. They further suggest that suppression of NO synthase activity may allow expansion of the number of hematopoietic stem and progenitor cells or neutrophils for therapeutic purposes.

Animals↗
PubMed2004

Ultrasound mediated intravesical transfection enhanced by treatment with lidocaine or heat.

PURPOSE: We have previously reported that cell membrane modification by lidocaine or heat can enhance ultrasound mediated transfection (USMT) on PC-3 cells in vitro. In the current study we investigated whether such enhancement could be observed using the T24 human bladder cancer cell line in vitro along with PC-3 in vivo. MATERIALS AND METHODS: For in vitro transfection T24 cells were sonicated with 1 MHz ultrasound at 3.6 W/cm (ISATA) for 20 seconds. For in vivo transfection T24 or PC-3 cells in the bladder were transabdominally sonicated with 1 MHz ultrasound at 0.78 W/cm (ISATA) for 60 seconds. Transfection efficiency was evaluated by the luciferase assay standardized with protein contents of the samples. RESULTS: Lidocaine or heat treatment of T24 cells during sonication enhanced luciferase expression significantly. Results indicated that enhancements could be achieved in a different cell line, although to lesser degrees than with PC-3 cells. In addition, membrane fluidity facilitation and cell viability after sonication were also different, presumably influenced by the different structures and/or compositions of the cell membranes. PC-3 and T24 cells were successfully transfected in the bladder. In addition, USMT enhancements were also observed in the 2 cell lines when sonicated with lidocaine or heat. CONCLUSIONS: These results suggest that USMT and its enhancement with lidocaine or heat can be applied for gene therapy in the bladder.

Animals↗
PubMed2004

Preliminary study: psychological effects of muscle relaxation on juvenile delinquents.

The purpose of this study is to test our hypothesis that muscle relaxation is effective on the psychological well-being of juvenile delinquents. Subjects were 16 juvenile delinquents who had entered a reform school. Subjects were divided into two groups. The muscle relaxation group received muscle relaxation therapy once a week for a total of 4 times. The control group spent an ordinary daily life in the reformatory. Psychological questionnaires used were the Rosenzweig Picture Frustration Study (P-F study), the Psychological Stress Response Scale (PSRS), and the Eysenck Personality Questionnaire (EPQ). There was a significant Group Time interaction of the Group Conformity Rating (GCR) of the P-F study (F [1,14] =10.1, P=0.007). There were no significant interactions in the other psychological subscales. Thus, muscle relaxation therapy may improve frustration tolerance among juvenile delinquents.

Adaptation, Psychological↗
PubMed2004

Alcohol consumption and mortality in Japan: the Miyagi Cohort Study.

BACKGROUND: We examined the association between alcohol consumption and all-cause mortality in Japanese men and women. METHODS: From June through August 1990, a total of 39,076 subjects (20,660 men and 18,416 women) in 14 municipalities of Miyagi Prefecture in rural northern Japan (40-64 years of age) completed a self-administered questionnaire that included information about alcohol consumption and various health habits. During 11 years of follow-up, we identified 1,879 deaths (1,335 men and 544 women). We used Cox proportional-hazards regression to estimate relative risk (RR) of all-cause mortality according to categories of alcohol consumption and to adjust for age, education, marital status, past histories of chronic diseases, body mass index, smoking, walking and dietary variables. RESULTS: Among men, the risk for all-cause mortality was significantly higher in past drinkers than never-drinkers (multivariate RR, 1.86; 95% confidence interval [CI], 1.50-2.29). There was a dose-response association between alcohol consumption and the risk of all-cause mortality among current drinking men: multivariate RRs in reference to never-drinkers (95% CI) were 1.10 (0.90-1.33), 1.17 (0.96-1.42), 1.16 (0.96-1.40), and 1.62 (1.32-1.99) in current drinkers who consumed less than 22.8 g, 22.8-45.5 g, 45.6-68.3 g, and 68.4 g or more alcohol per day, respectively (P for trend<0.001). Similar association was observed among women (P for trend=0.005). CONCLUSIONS: The results indicated that alcohol consumption tended to be associated with linear increase in risk of all-cause mortality among Japanese men and women, and the association was remarkable for younger men.

Adult↗
PubMed2004

Follow-up and mortality profiles in the Miyagi Cohort Study.

BACKGROUND: Findings from a large-scale population-based prospective cohort would lead us to better understanding of the relationship between lifestyle and health, thus better provision of strategies for disease prevention and health promotion. METHODS: We conducted a baseline survey with two self-administered questionnaires regarding lifestyle and personality on the residents aged 40 to 64 years in 14 municipalities of Miyagi Prefecture, Japan, during June through August, 1990. Out of the eligible 51,925 residents, 47,605 (91.7%) responded to the lifestyle questionnaire and formed the cohort under study. We then have been following up the subjects for mortality, migration, and incidence of cancer. RESULTS: During the follow-up from June 1990 through March 2001, 2,536 subjects (5.3%) died and 2,166 subjects (4.5%) emigrated. The distribution of the causes of death among the study subjects was quite consistent with the national average. CONCLUSIONS: In this cohort study, both the participation rate and the follow-up rate are satisfactorily high. We expect this Miyagi Cohort Study to provide the society with evidence for health promotion and disease prevention.

Adult↗
PubMed2004

Body mass index and mortality in Japan: the Miyagi Cohort Study.

BACKGROUND: The relation between body mass index (BMI) and mortality is not well established. The objective of this study was to examine the association in Japanese adults. METHODS: In 1990, 18,740 men and 20,870 women in Miyagi Prefecture in rural northern Japan (40-64 years of age) completed a self-administered questionnaire including height and weight. Cox regression was used to estimate relative risk (RR) of mortality according to levels of BMI, with adjustment for age, marital status, smoking, drinking, walking, and weight change since 20 years of age. RESULTS: During 11 years of follow-up, 1,121 men and 567 women had died. Compared with the referent BMI category (23.0-24.9), women in the highest BMI category (BMI>30.0) had a RR of death of 1.64 (95% confidence interval (CI), 1.09-2.49) and men and women in the lowest BMI categories (BM1<18.5) had a RR of death of 2.06 (95% CI, 1.49-2.84) and 1.83 (95% CI, 1.17-2.88), respectively, after adjustment for potential confounders and after exclusion of deaths occurring in the first three years of follow-up. We did not observe significant differences in mortality for subjects with wide range of BMI (18.5 or higher in men and 18.5 to 29.9 in women). CONCLUSIONS: The risk of death from all causes increases in lean men and women, and obese women in this cohort.

Adult↗
PubMed2004

Health practices and mortality in Japan: combined effects of smoking, drinking, walking and body mass index in the Miyagi Cohort Study.

BACKGROUND: Evidence is limited regarding the association between the combinations of multiple health practices and mortality. METHODS: In 1990, 28,333 men and women in Miyagi Prefecture in rural northern Japan (40-64 year of age) completed a self-administered questionnaire. A lifestyle score was calculated by adding the number of high-risk practices (smoking, consuming > or = 22.8 g alcohol/d, walking < 1 hr/d, body mass index < 18.5 or > or = 30.0). Cox regression was used to estimate relative risk (RR) of mortality according to the lifestyle score, with adjustment for age, education, marital status, past history of diseases, and dietary variables. During 11 years of follow-up, 1,200 subjects had died. RESULTS: We observed linear increase in risk of death associated with increasing number of high-risk practices: compared with men who had no high-risk practices, multivariate RRs for men who had 1 to 4 practices were 1.20, 1.66, 1.94, and 3.96, respectively (P for trend<0.001), and corresponding RRs for women were 1.31, 2.14, 3.98, 5.56, respectively (P for trend<0.001). A unit increase in the number of high-risk practices corresponded to being 2.8 and 4.8 years older for men and women, respectively. CONCLUSIONS: In this prospective cohort study of middle-aged men and women in rural Japan, a larger number of high-risk practices was associated with linear increase in risk of all-cause mortality.

Adult↗
PubMed2004

[Association between social support and depression in the elderly Japanese population].

To determine the association between social support and depression in elderly Japanese, we conducted a Comprehensive Geriatric Assessment among residents aged 70 years or over. Out of 2,730 eligible subjects, 1,179 participated in the survey and 1,146 (480 men and 666 women) were analyzed. The Geriatric Depression Scale (GDS) was used to estimate depression status. The subjects were divided into two groups: depressive (GDS>11 or taking antidepressant drugs) and non-depressive (GDS<11). Various levels of social support were assessed by the following questions: Do you have someone (1) whom you can consult when you are in trouble ? (2) whom you can consult when your physical condition is not good ? (3) who can help you in daily housework ? (4) who can take you to a hospital when you don't feel well ? (5) who can take care of you when you are ill in bed? In multivariate logistic regression analysis, the calculated odds ratios (95% CIs) for the lack of each type of social support for depression status were: (1) 2.5 (1.5-4.1),(2) 1.9 (1.1-3.2),(3) 2.7 (1.7-4.4),(4) 1.9 (1.1-3.2),(5) 2.8 (1.6-4.9) in men, and (1) 1.2 (0.8-1.8),(2) 1.2 (0.8-1.8),(3) 1.4 (1.0-2.0),(4) 1.6 (1.1-2.3),(5) 2.0 (1.4-2.9) in women. A significant association was found between social support and depression in this elderly population. We also found that this association was stronger in men.

Aged↗
PubMed2004

Laterality and imbalance of muscle stiffness relate to personality.

The authors' purpose in this study was to test the hypothesis that laterality and imbalance of muscle stiffness relate to personality. The authors selected 23 healthy volunteers and divided them into two groups based on the predominance of muscle stiffness on the left or right side. Imbalance of muscle stiffness was calculated as the absolute value of the difference of muscle stiffness between the right and left sides. The authors evaluated personality with the Japanese version of the Eysenck Personality Questionnaire. Subjects with left predominant muscle stiffness of the rectal abdominis had significantly higher neuroticism score than those with right predominant muscle stiffness. Subjects with more imbalance of muscle stiffness in the latissimus dorsi and in the trapezius had significantly higher neuroticism and psychoticism scores than those with less imbalance. The findings suggest that laterality and imbalance of muscle stiffness relate to personality.

Adult↗
PubMed2004

[A survey regarding the implementation of cancer screening among municipalities in Japan].

OBJECTIVE: The objective of this study was to conduct a survey regarding implementation of cancer screening in all municipalities in Japan. METHODS: In February 2003, we sent out a questionnaire regarding cancer screening to all 3,242 municipalities in Japan. RESULTS: A total of 2,342 municipalities (72.2%) completed and returned the questionnaire. In the year 2002, the percentages of municipalities which implemented each cancer screening were 49.4% for breast cancer using mammography, 33.7% for prostate cancer, 20.3% for cervical cancer for women younger than 30 years old, 5.7% for lung cancer using helical CT, 5.0% for gastric cancer using the PG method and 4.8% for ovarian cancer. CONCLUSIONS: Screening for breast cancer using mammography, as recommended by the 4-th plan for Health Services for the Aged, was implemented by less than half of the municipalities. Parameters, including eligible age group, target group, and method, widely differed among the municipalities. A standardized system for cancer screening programs should be recommended.

Cities↗
PubMed2003

Nitric oxide activates diverse signaling pathways to regulate gene expression.

Nitric oxide signaling is crucial for effecting long lasting changes in cells, including gene expression, cell cycle arrest, apoptosis, and differentiation. We have determined the temporal order of gene activation induced by NO in mammalian cells and have examined the signaling pathways that mediate the action of NO. Using microarrays to study the kinetics of gene activation by NO, we have determined that NO induces three distinct waves of gene activity. The first wave is induced within 30 min of exposure to NO and represents the primary gene targets of NO. It is followed by subsequent waves of gene activity that may reflect further cascades of NO-induced gene expression. We verified our results using quantitative real time PCR and further validated our conclusions about the effects of NO by using cytokines to induce endogenous NO production. We next applied pharmacological and genetic approaches to determine the signaling pathways that are used by NO to regulate gene expression. We used inhibitors of particular signaling pathways, as well as cells from animals with a deleted p53 gene, to define groups of genes that require phosphatidylinositol 3-kinase, protein kinase C, NF-kappaB, p53, or combinations thereof for activation by NO. Our results demonstrate that NO utilizes several independent signaling pathways to induce gene expression.

3T3 Cells↗
PubMed2003

Personality and the risk of cancer.

BACKGROUND: The role of personality in the causation of cancer has been controversial. We examined this question in a large, prospective study. METHODS: From June through August 1990, 30 277 residents of Miyagi Prefecture in northern Japan completed a Japanese version of the short form of the Eysenck Personality Questionnaire-Revised and a questionnaire on various health habits. There were 671 prevalent cases of cancer at baseline, and 986 incident cases of cancer were identified during 7 years of follow-up, through December 1997. We used Cox proportional hazards regression to estimate the relative risk (RR) of incident cancer (total, stomach, colorectal, breast, and lung) according to four levels of each of four personality subscales (extraversion, neuroticism, psychoticism, and lie), with adjustment for sex, age, education, smoking, alcohol use, body mass index, and family history of cancer. Statistical tests were two-sided. RESULTS: Multivariable RRs of total cancer for individuals in the highest level of each personality subscale as compared with those in the lowest were 0.9 for extraversion (95% confidence interval [CI] = 0.7 to 1.1; P(trend) =.32), 1.1 for psychoticism (95% CI = 0.9 to 1.3; P(trend) =.96), 0.9 for lie (95% CI = 0.7 to 1.0; P(trend) =.19), and 1.2 for neuroticism (95% CI = 1.0 to 1.4; P(trend) =.06). There were no associations between any personality subscale and risk of specific cancers. Neuroticism showed statistically significant positive, linear associations with prevalent cancer at baseline (P(trend)<.001) and with the 320 incident cancer cases diagnosed within the first 3 years of follow-up (P(trend) =.03); however, it showed no association with the 666 cases diagnosed during the fourth through the seventh years of follow-up (P(trend) =.43). CONCLUSION: Our data do not support the hypothesis that personality is a risk factor for cancer incidence. The association between neuroticism and prevalent cancer may be a consequence, rather than a cause, of cancer diagnosis or symptoms.

Adult↗
PubMed2002

Validation of walking questionnaire for population-based prospective studies in Japan: comparison with pedometer.

PURPOSE: To assess the reproducibility and validity of a single-item, self-administered questionnaire on walking used in two population-based prospective cohort studies in northern Japan, using pedometer counts as the reference standard. METHODS: Fifty-one men and 55 women participating in the main cohort studies (mean age: 61.7 years) responded to a question on the average duration of walking per day five times at 3-month intervals. The subjects also provided 3 consecutive days of pedometer counts four times along with the first four questionnaire surveys. RESULTS: For the first and the fifth questionnaires administered one year apart, 55% of the subjects chose concordant categories among three options (< or = 30 min/ between 30 and 60 min/> or = 60 min), and 13% chose the highest category in one questionnaire and the lowest in the other questionnaire. The sex- and age-adjusted mean daily numbers of walking steps counted by the pedometer were 5,857, 7,047, and 7,621 for the three categories of walking duration in the fifth questionnaire, and it showed significant linear associations with all of the five questionnaire measurements. CONCLUSION: The single-item questionnaire on walking is reasonably reproducible and valid, and useful in studying the health effects of walking among the Japanese population.

Cohort Studies↗
PubMedDate not supplied

Personality and mortality from ischemic heart disease and stroke.

BACKGROUND: The role of personality in the causation of circulatory diseases has been controversial. METHODS: From June through August 1990, 41,442 residents of Miyagi Prefecture in northern Japan completed the Japanese version of the short-form Eysenck Personality Questionnaire-Revised and another questionnaire on various health habits. During 11 years of follow-up until March 31, 2001, we identified 90 deaths from ischemic heart disease (IHD) and 131 deaths from stroke. We used Cox regression to estimate the relative risk of IHD and stroke according to the three levels of four personality subscales (extraversion, neuroticism, psychoticism, and lie), with adjustment for sex, age, and other potentially confounding variables. RESULTS: Multivariate relative risks of IHD for the highest verses the lowest level of personality subscales were 0.7 for extraversion, 1.1 for neuroticism, 1.3 for psychoticism, and 0.8 for lie. Multivariate relative risks of stroke for the highest verses the lowest level of personality subscales were 1.0 for extraversion, 0.9 for neuroticism, 1.2 for psychoticism, and 1.2 for lie. CONCLUSIONS: This prospective study does not support the hypothesis that personality is a risk factor for mortality from IHD and stroke.

Female↗