89 results on '"Wakabayashi C"'
Search Results
2. Fuzzy control of a nylon polymerization semi-batch reactor
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Wakabayashi, C., Embiruçu, M., Fontes, C., and Kalid, R.
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- 2009
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3. Sexual activities and social relationships of people with HIV in Japan
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Inoue, Y., Yamazaki, Y., Seki, Y., Wakabayashi, C., and Kihara, M.
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- 2004
4. Antihelminthic potential of quinacrine and oxyclozanide against gill parasite Microcotyle sebastis in black rockfish Sebastes schlegeli
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Kang, YJ, primary, Wakabayashi, C, additional, and Kim, KH, additional
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- 2016
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5. Strengthening spot weld joint by autotempering acceleration at heat affected zone
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Wakabayashi, C., primary, Furusako, S., additional, and Miyazaki, Y., additional
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- 2015
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6. The relationship exercise habits and sleep in community-dwelling people
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Kitabatake, Y., primary, Wakabayashi, C., additional, Nobuhara, H., additional, and Sakai, H., additional
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- 2014
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7. Estimation of Weibull parameters from parameters of initial distribution of flaw size
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Wakabayashi, C, primary, Yasuda, K, additional, and Shiota, T, additional
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- 2009
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8. How HIV infected haemophiliacs in Japan were informed of their HIV-positive status
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Seki, Y., primary, Yamazaki, Y., additional, Inoue, Y., additional, Wakabayashi, C., additional, and Seto, S., additional
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- 2002
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9. Effect of Nicorandil on Exercise Performance in Patients with Effort Angina.
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Kato, K., Asanoi, H., Wakabayashi, C., Hosoda, S., Shiina, A., Hosono, K., Kurita, A., Seki, K., Ishida, K., Kuroiwa, A., and Fukumoto, A.
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- 1987
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10. Zero magnetostriction iron films.
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Ishiwata, N., Wakabayashi, C., and Matsumoto, T.
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- 1988
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11. Magnetic and structural properties of dual ion beam sputtered pure iron films.
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Ishiwata, N., Wakabayashi, C., and Matsumoto, T.
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- 1987
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12. A. Study on Corrosion Resistance of Dual Ion Beam Sputtered Fe-Base Films
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Wakabayashi, C., primary, Ishiwata, N., additional, and Matsumoto, T., additional
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- 1988
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13. Investigating the Moderating Effect of HIV Status Disclosure on the Link Between Discrimination Experience and Psychological Distress Among People Living with HIV in Japan Infected Through Sexual Contact.
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Miwa T, Wakabayashi C, Hayashi K, Tanuma J, Ikeda K, Yokomaku Y, and Ikushima Y
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Background: There is a scarcity of research on the potential impact of disclosing HIV status to friends and family in moderating the adverse effects of discrimination on the mental health of people living with HIV (PLWH). This study assessed the experiences of discrimination and HIV status disclosure among PLWH in Japan, and evaluated their potential associations with psychological distress., Method: Data were derived from a nationwide cross-sectional survey of PLWH conducted in Japan between 2019 and 2020. The interaction effects of HIV-related discrimination and HIV status disclosure on the psychological distress were examined using logistic and linear regression analyses., Results: The median age of the 804 respondents was 46 years old. Most respondents were male and 85.4% (687/804) identified as homosexuals or bisexuals. A total of 12.7% (102/804) of the respondents reported that they had recently experienced discrimination because of their HIV status. Experience of HIV-related discrimination was independently associated with high psychological distress (adjusted OR 2.02; 95% CI, 1.15-3.57), and HIV status disclosure to friends partially weakened the association between discrimination and the level of psychological distress (regression coefficient -3.115; p = 0.004)., Conclusion: While measures that aim to end discrimination remain vital, increasing the opportunities of PLWH to communicate with friends they feel comfortable disclosing their HIV status may also be helpful in protecting their mental health., (© 2024. The Author(s).)
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- 2024
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14. Possible involvement of Interleukin-17A in the deterioration of prepulse inhibition on acoustic startle response in mice.
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Wakabayashi C and Kunugi H
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- Mice, Male, Animals, Interleukin-17, Mice, Inbred C57BL, Acoustics, Prepulse Inhibition, Reflex, Startle physiology
- Abstract
Aim: Proinflammatory cytokines such as interleukin-6 (IL-6) and IL-17A have been implicated in the pathophysiology of schizophrenia which often shows sensorimotor gating abnormalities. This study aimed to examine whether a proinflammatory cytokine, IL-17A, induces impairment in sensorimotor gating in mice. We also examined whether IL-17A administration affects GSK3α/β protein level or phosphorylation in the striatum., Methods: Recombinant mouse IL-17A (low-dose: 0.5 ng/mL and high-dose: 50 ng/mL with 10 μL/g mouse body weight, respectively) or vehicle was intraperitoneally administered into C57BL/6 male mice 10 times in 3 weeks (sub-chronic administration). Prepulse inhibition test using acoustic startle stimulus was conducted 4 weeks after the final IL-17A administration. We evaluated the effect of IL-17A administration on protein level or phosphorylation of GSK3α/β in the striatum by using Western blot analysis., Results: Administration of IL-17A induced significant PPI deterioration. Low-dose of IL-17A administration significantly decreased both GSK3α (Ser21) and GSK3β (Ser9) phosphorylation in mouse striatum. There was no significant alteration of GSK3α/β protein levels except for GSK3α in low-dose IL-17A administration group., Conclusion: We demonstrated for the first time that sub-chronic IL-17A administration induced PPI disruption and that IL-17A administration resulted in decreased phosphorylation of GSKα/β at the striatum. These results suggest that IL-17A could be a target molecule in the prevention and treatment of sensorimotor gating abnormalities observed in schizophrenia., (© 2023 The Authors. Neuropsychopharmacology Reports published by John Wiley & Sons Australia, Ltd on behalf of The Japanese Society of Neuropsychopharmacology.)
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- 2023
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15. Characterizing changes in drug use behaviour following supply shortages of 5-MeO-DIPT, alkyl nitrites and new psychoactive substances among men living with HIV in Japan.
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Hayashi K, Wakabayashi C, Ikushima Y, and Tarui M
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- Male, Humans, Nitrites, Homosexuality, Male, Sexual Behavior, Japan epidemiology, Risk-Taking, HIV Infections epidemiology, Sexual and Gender Minorities, Substance-Related Disorders epidemiology, Methamphetamine
- Abstract
Background: Since 2005, Japan has incrementally banned a range of new psychoactive substances (NPS), including 5-MeO-DIPT (5MO; foxy) and alkyl nitrites (AN; rush, poppers) that have commonly been used among men who have sex with men (MSM). After the largest ban in 2014, these drugs were reported to have disappeared from the domestic market. Given that 5MO/AN/NPS use has been prevalent among men living with HIV in Japan, a population largely comprised of MSM, we sought to characterize changes in their drug use behavior following the supply shortages., Methods: Using data from two waves of a nationwide survey of people living with HIV in Japan in 2013 and 2019-20 (n = 1042), we employed multivariable modified Poisson regression to identify correlates of self-reported reactions to the 5MO/AN/NPS shortages and changes in drug use behavior in 2019-20 vs. 2013., Results: Among 391 men (96.7% MSM) surveyed in 2019-20, following the supply shortages, 234 (59.8%) stopped using 5MO/AN/NPS, 52 (13.3%) retained access to the supply, and 117 (29.9%) used substitute drugs: most commonly, methamphetamine (60.7%). Individuals who used substitutes were more likely to report unprotected sex (adjusted relative risk [ARR]=1.67; 95% confidence interval [CI]: 1.13-2.47) as well as low (ARR=2.35; 95% CI: 1.46-3.79) and lower middle (vs. upper middle to high) socioeconomic status (ARR=1.55; 95% CI: 1.00-2.41). The prevalence of past-year methamphetamine use (ARR=1.93; 95% CI: 1.11-3.35) and self-reported uncontrollable drug use (ARR=1.62; 95% CI: 1.07-2.53) were significantly higher in 2019-20 compared to 2013., Conclusion: Following the supply shortages, approximately one-fifth of our participants used methamphetamine as a substitute for 5MO/AN/NPS. Methamphetamine use and perceived uncontrollable drug use also appeared to have increased at the population level after the supply shortages. These findings suggest a potentially harmful substance displacement effect of the aggressive ban. Harm reduction interventions are needed in this population., Competing Interests: Declarations of Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)
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- 2023
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16. Associations between Drug Use and Sexual Risk Behaviours among Men Who Have Sex with Men in Japan: Results from the Cross-Sectional LASH Study.
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Miwa T, Yamaguchi M, Ohtsuki T, Oshima G, Wakabayashi C, Nosaka S, Hayashi K, Ikushima Y, and Tarui M
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- Male, Humans, Homosexuality, Male, Cross-Sectional Studies, Japan epidemiology, Sexual Behavior, Sexual Partners, Risk-Taking, HIV Infections epidemiology, Sexual and Gender Minorities, Sexually Transmitted Diseases epidemiology, Substance-Related Disorders epidemiology
- Abstract
This study assessed drug use patterns among men who have sex with men (MSM) in Japan, and evaluated their potential associations with sexual risk behaviours. Between September and October 2016, study subjects were recruited through a cross-sectional survey (LASH: Love Life and Sexual Health) using a geosocial networking application for MSM. Of the participants, 25.4% (1756/6921) reported ever having used drugs, and 11.3% (780/6921) reported having done so in the past six months. Those who used drugs were more likely to have greater knowledge of HIV/sexually transmitted infections (STIs). Drug use in the past six months was independently associated with each of the following sexual risk behaviours in the same period: (i) six or more sexual partners (adjusted odds ratio [aOR] = 2.70, 95% confidence interval [CI]: 2.30-3.17); (ii) condomless anal intercourse (aOR = 2.88, 95% CI: 2.43-3.42); (iii) group sex (aOR = 2.60, 95% CI: 2.22-3.05); and (iv) sex work (aOR = 2.30, 95% CI: 1.67-3.16). These results suggest that MSM in Japan who use drugs are more likely to report sexual risk behaviours, while also having greater knowledge of HIV/STIs. Supporting MSM to minimise the harm from drug use may be helpful in reducing HIV transmission among this priority population.
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- 2023
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17. Involvement of IL-6 and GSK3β in impaired sensorimotor gating induced by high-fat diet.
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Wakabayashi C and Kunugi H
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- Animals, Antibodies, Monoclonal immunology, Corpus Striatum enzymology, Corpus Striatum metabolism, Interleukin-6 immunology, Male, Mice, Mice, Inbred C57BL, Phosphorylation, Tumor Necrosis Factor-alpha blood, Antibodies, Monoclonal pharmacology, Diet, High-Fat adverse effects, Glycogen Synthase Kinase 3 beta metabolism, Interleukin-6 blood, Prepulse Inhibition physiology, Sensory Gating physiology
- Abstract
Increased levels of proinflammatory cytokines have been implicated in schizophrenia; however, their pathophysiological roles in abnormal brain dysfunctions remain unclear. We evaluated the effect of proinflammatory cytokines on a high-fat diet (HFD)-induced prepulse inhibition (PPI) deficits in the acoustic startle response. Eight-week-old male C57BL/6J mice were fed a HFD for 3 weeks and then PPI was examined. HFD significantly induced PPI deficits and increased plasma IL-6, but not TNFα, levels. Interestingly, MR16-1 administration during the HFD period ameliorated PPI deficits. Further, in the striatum of HFD-fed mice, phosphorylation of GSK3β, but not GSK3α, was significantly increased; this increase was attenuated by MR16-1, although the protein levels of GSK3α and β were not altered. There were no significant differences in either phosphorylation or protein levels of GSK3α, β in the PFC during the HFD period. These results suggest that increased IL-6 levels during HFD may induce sensorimotor gating deficits, likely through the alteration of striatal GSK3β phosphorylation. MR16-1 might have a beneficial effect on such HFD-induced sensorimotor gating deficits., (Copyright © 2018 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)
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- 2019
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18. The prevalence and risk factor control associated with noncommunicable diseases in China, Japan, and Korea.
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Ma D, Sakai H, Wakabayashi C, Kwon JS, Lee Y, Liu S, Wan Q, Sasao K, Ito K, Nishihara K, and Wang P
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- Adult, Age Distribution, China epidemiology, Cross-Sectional Studies, Diet statistics & numerical data, Female, Humans, Japan epidemiology, Male, Marital Status statistics & numerical data, Middle Aged, Prevalence, Republic of Korea epidemiology, Risk Factors, Sex Distribution, Young Adult, Angina Pectoris epidemiology, Diabetes Mellitus epidemiology, Diet psychology, Hyperlipidemias epidemiology, Hypertension epidemiology
- Abstract
Background: Noncommunicable disease (NCD) has become the leading cause of mortality and disease burden worldwide., Methods: A cross-sectional survey was carried out to investigate the prevalence of NCDs and risk factor control on dietary behaviors and dietary intake in China, Japan, and Korea., Results: There were significant differences among the three countries on the prevalence of hypertension (24.5% in China, 17.6% in Korea, and 15.2% in Japan), diabetes (8.9% in China, 5.7% in Korea, and 4.8% in Japan), hyperlipidemia (13.1% in China, 9.2% in Korea, and 6.9% in Japan), and angina pectoris (3.6% in China, 1.7% in Korea, and 1.5% in Japan). The prevalence rate of hypertension, diabetes, hyperlipidemia, and angina pectoris was highest in China and lowest in Japan. However, 82.2%, 48.4%, and 64.4% of Chinese, Koreans, and Japanese presented good dietary behavior, respectively. Multivariable logistic regression analysis found that sex, age, and marital status were predictors of good dietary behavior. In addition, in comparison with subjects without hypertension, diabetes, or hyperlipidemia, subjects with hypertension, diabetes, or hyperlipidemia significantly improved their dietary behaviors and controlled their intake of salt, sugar, and oil., Conclusions: The prevalence of NCDs and trends in major modifiable risk factor control in China, Korea, and Japan remain troubling. Public efforts to introduce healthy lifestyle changes and systematic NCDs prevention programs are necessary to reduce the epidemic of NCDs in these three Asian countries., (Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.)
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- 2017
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19. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study.
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Hidese S, Ota M, Wakabayashi C, Noda T, Ozawa H, Okubo T, and Kunugi H
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- Adult, Anxiety complications, Anxiety drug therapy, Cognition drug effects, Depressive Disorder, Major complications, Female, Glutamates administration & dosage, Humans, Male, Mental Status Schedule, Middle Aged, Stroop Test, Treatment Outcome, Depressive Disorder, Major drug therapy, Glutamates therapeutic use
- Abstract
Objective: l-theanine, an amino acid uniquely contained in green tea (Camellia sinensis), has been suggested to have various psychotropic effects. This study aimed to examine whether l-theanine is effective for patients with major depressive disorder (MDD) in an open-label clinical trial., Methods: Subjects were 20 patients with MDD (four males; mean age: 41.0±14.1 years, 16 females; 42.9±12.0 years). l-theanine (250 mg/day) was added to the current medication of each participant for 8 weeks. Symptoms and cognitive functions were assessed at baseline, 4, and 8 weeks after l-theanine administration by the 21-item version of the Hamilton Depression Rating Scale (HAMD-21), State-Trait Anxiety Inventory (STAI), Pittsburgh Sleep Quality Index (PSQI), Stroop test, and Brief Assessment of Cognition in Schizophrenia (BACS)., Results: HAMD-21 score was reduced after l-theanine administration (p=0.007). This reduction was observed in unremitted patients (HAMD-21>7; p=0.004) at baseline. Anxiety-trait scores decreased after l-theanine administration (p=0.012) in the STAI test. PSQI scores also decreased after l-theanine administration (p=0.030) in the unremitted patients at baseline. Regarding cognitive functions, response latency (p=0.001) and error rate (p=0.036) decreased in the Stroop test, and verbal memory (p=0.005) and executive function (p=0.016) were enhanced in the BACS test after l-theanine administration., Conclusion: Our study suggests that chronic (8-week) l-theanine administration is safe and has multiple beneficial effects on depressive symptoms, anxiety, sleep disturbance and cognitive impairments in patients with MDD. However, since this is an open-label study, placebo-controlled studies are required to consolidate the effects.
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- 2017
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20. High prevalence of quasi-legal psychoactive substance use among male patients in HIV care in Japan: a cross-sectional study.
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Hayashi K, Wakabayashi C, Ikushima Y, and Tarui M
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- Adult, Cross-Sectional Studies, Female, Humans, Japan, Legislation, Drug, Male, Middle Aged, Prevalence, HIV Infections psychology, Psychotropic Drugs administration & dosage
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Background: Syndemics of illicit drug use and HIV remain as significant public health issues around the world. There has been increasing concern regarding the rapidly growing market of new psychoactive substances, particularly in Asia. In response, the Japanese government has increasingly banned such substances in recent years. We sought to identify the prevalence and correlates of use of quasi-legal psychoactive substances among people living with HIV/AIDS (PLHIV) in Japan., Methods: Data were derived from a nationwide survey of PLHIV conducted at nine leading HIV/AIDS care hospitals between July and December 2013. The prevalence and correlates of the use of quasi-legal psychoactive substances (e.g., synthetic cannabinoids, cathinone derivatives, etc. that had not been prohibited from using at the time of survey) among male participants were examined using multivariate survey logistic regression., Results: Among 963 study participants, the majority (95.3%) were male. The most commonly used drug among men was quasi-legal psychoactive substances (55.3% ever and 12.8% in the previous year). In multivariate analysis, the lifetime use of tryptamine-type derivatives (i.e., 5-MeO-DIPT or N,N-diisopropyl-5-methoxytryptamine) (adjusted odds ratio [AOR]: 2.42; 95% confidence interval [CI]: 1.36-4.28) and methamphetamine/amphetamine (AOR: 3.59; 95% CI: 2.13-6.04) were independently associated with recent quasi-legal psychoactive substance use., Conclusions: In our sample of male PLHIV in Japan, quasi-legal psychoactive substances were the most commonly used drugs. Individuals who had ever used tryptamine-type derivatives or methamphetamine/amphetamine were more likely to report recent quasi-legal psychoactive substance use, suggesting a potential shift in drug use patterns from regulated to unregulated substances among this population. These findings indicate a need for further research to examine implications for HIV care.
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- 2017
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21. Recreational drug use and related social factors among HIV-positive men in Japan.
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Togari T, Inoue Y, Takaku Y, Abe S, Hosokawa R, Itagaki T, Yoshizawa S, Oki S, Katakura N, Yamauchi A, Wakabayashi C, and Yajima T
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- Adult, Comorbidity, Cross-Sectional Studies, Humans, Japan epidemiology, Male, Middle Aged, Needs Assessment, Social Support, Socioeconomic Factors, Drug Users classification, Drug Users psychology, Drug Users statistics & numerical data, HIV Infections epidemiology, HIV Infections prevention & control, HIV Infections psychology, Illicit Drugs classification, Illicit Drugs pharmacology, Substance-Related Disorders epidemiology, Substance-Related Disorders prevention & control, Substance-Related Disorders psychology
- Abstract
This study aims to determine the relationship between recreational drug use in HIV-positive males in the past year and socio-economic factors and/or social support networks in Japan. A national online survey in a cross-sectional study was conducted by HIV Futures Japan project from July 2013 to February 2014. Of the 1095 HIV-positive individuals who responded, 913 responses were determined to be valid; responses from the 875 males were analysed. A total of 282 participants used addictive drugs (32.2%) in past year. New psychoactive substances were used by 121 participants (13.8%), methamphetamine or amphetamine by 47 (5.4%), air dusters/sprays/gas by 31 (3.5%), 5-methoxy-N,N-diisopropyltryptamine (5MeO-DIPT) by 16 (1.8%) and cannabis (1.0%) by 9. Multiple logistic regression analysis was performed with the use of alkyl nitrites, addictive drugs, air dusters and thinners, which are low illegality, as dependent variables. We found that the odds ratio (95% confidence interval) for use among participants with full-time and temp/contracted/part-time employees compared to management/administration professions were 2.59 (0.99-6.77) and 2.61 (0.91-7.51). Also, a correlation was observed between alkyl nitrites and new psychoactive substances and usage rates in people engaged in few HIV-positive networks. It is necessary to develop targeted policies for drug use prevention and user support among HIV-positive men and to support and provide care for drug users who are isolated or have a narrow HIV/AIDS support network.
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- 2016
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22. Possible role of the dopamine D1 receptor in the sensorimotor gating deficits induced by high-fat diet.
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Wakabayashi C, Numakawa T, Ooshima Y, Hattori K, and Kunugi H
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- 3,4-Dihydroxyphenylacetic Acid metabolism, Animals, Benzazepines pharmacology, Dopamine metabolism, Homovanillic Acid metabolism, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Prefrontal Cortex drug effects, Prepulse Inhibition drug effects, Prepulse Inhibition physiology, Receptors, Dopamine D1 antagonists & inhibitors, Receptors, Dopamine D2 genetics, Receptors, Dopamine D2 metabolism, Reflex, Startle physiology, Sensory Gating physiology, Diet, High-Fat, Dopamine Antagonists pharmacology, Prefrontal Cortex metabolism, Receptors, Dopamine D1 metabolism, Reflex, Startle drug effects, Sensory Gating drug effects
- Abstract
Rationale: High-fat diet (HFD) has been recently reported to induce sensorimotor gating deficits, but the underlying mechanisms are not well understood., Objective: The purpose of this study is to determine whether HFD induces long-lasting deficits in sensorimotor gating and to examine the involvement of altered dopamine (DA) function., Methods: C57BL/6J mice were fed HFD for 10 weeks and then normal diet (ND) for 4 weeks. DA D2 receptor (D2R) knockout (KO) mice were also fed HFD for 10 weeks. The mice were evaluated for prepulse inhibition (PPI) of acoustic startle after HFD and the subsequent 4-week ND. We evaluated the effect of SCH23390, a D1 receptor (D1R) antagonist, on PPI and measured protein expression levels of D1R and D2R in the prefrontal cortex (PFC) in HFD mice. The concentrations of monoamines and their metabolites in the cortices of 10-week HFD or ND mice were measured using high performance liquid chromatography., Results: Long-term HFD-induced PPI disruption in WT and D2R KO mice. Even after 4 weeks of subsequent ND, PPI remained to be disrupted. SCH23390 mitigated the PPI disruption. In HFD animals, D1R protein expression in the PFC was significantly decreased, while DA, homovanillic acid, and 3,4-dihydroxyphenylacetic acid levels in the cortex were increased., Conclusion: This is the first evidence that HFD can induce long-lasting deficits in sensorimotor gating through alteration of cortical levels of DA and its metabolites. Our data suggest that HFD-induced PPI deficits are related to altered D1R signaling and that D1R antagonists may have therapeutic effects on the deficits.
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- 2015
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23. Effect of L-theanine on glutamatergic function in patients with schizophrenia.
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Ota M, Wakabayashi C, Sato N, Hori H, Hattori K, Teraishi T, Ozawa H, Okubo T, and Kunugi H
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- Adult, Antipsychotic Agents administration & dosage, Brain drug effects, Brain metabolism, Case-Control Studies, Female, Humans, Magnetic Resonance Spectroscopy methods, Male, Middle Aged, Sleep drug effects, Treatment Outcome, Glutamates administration & dosage, Glutamic Acid metabolism, Glutamine metabolism, Schizophrenia drug therapy, Schizophrenia metabolism
- Abstract
Objectives: Glutamatergic dysfunction in the brain has been implicated in the pathophysiology of schizophrenia. Previous studies suggested that L-theanine affects the glutamatergic neurotransmission and ameliorates symptoms in patients with schizophrenia. The aims of the present study were twofold: to examine the possible effects of L-theanine on symptoms in chronic schizophrenia patients and to evaluate the changes in chemical mediators, including glutamate + glutamine (Glx), in the brain by using 1H magnetic resonance spectroscopy (MRS)., Method: The subjects were 17 patients with schizophrenia and 22 age- and sex-matched healthy subjects. L-theanine (250 mg/day) was added to the patients' ongoing antipsychotic treatment for 8 weeks. The outcome measures were the Positive and Negative Syndrome Scale (PANSS), Pittsburgh Sleep Quality Index scores and MRS results., Results: There were significant improvements in the PANSS positive scale and sleep quality after the L-theanine treatment. As for MRS, we found no significant differences in Glx levels before and after the 8 week L-theanine treatment. However, significant correlations were observed between baseline density of Glx and change in Glx density by l-theanine., Conclusions: Our results suggest that L-theanine is effective in ameliorating positive symptoms and sleep quality in schizophrenia. The MRS findings suggest that L-theanine stabilises the glutamatergic concentration in the brain, which is a possible mechanism underlying the therapeutic effect.
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- 2015
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24. IL-1 receptor-antagonist (IL-1Ra) knockout mice show anxiety-like behavior by aging.
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Wakabayashi C, Numakawa T, Odaka H, Ooshima Y, Kiyama Y, Manabe T, Kunugi H, and Iwakura Y
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- Aging metabolism, Animals, Anti-Anxiety Agents therapeutic use, Anxiety drug therapy, Anxiety genetics, Anxiety metabolism, Biogenic Monoamines metabolism, Diazepam therapeutic use, Hippocampus metabolism, Maze Learning, Mice, Knockout, Receptors, Glucocorticoid metabolism, Receptors, Mineralocorticoid metabolism, Aging psychology, Anxiety psychology, Interleukin 1 Receptor Antagonist Protein genetics
- Abstract
Interleukin 1 (IL-1) plays a critical role in stress responses, and its mRNA is induced in the brain by restraint stress. Previously, we reported that IL-1 receptor antagonist (IL-1Ra) knockout (KO) mice, which lacked IL-1Ra molecules that antagonize the IL-1 receptor, showed anti-depression-like behavior via adrenergic modulation at the age of 8 weeks. Here, we report that IL-1Ra KO mice display an anxiety-like phenotype that is induced spontaneously by aging in the elevated plus-maze (EPM) test. This anxiety-like phenotype was improved by the administration of diazepam. The expression of the anxiety-related molecule glucocorticoid receptor (GR) was significantly reduced in 20-week-old but not in 11-week-old IL-1Ra KO mice compared to wild-type (WT) littermates. The expression of the mineralocorticoid receptor (MR) was not altered between IL-1Ra KO mice and WT littermates at either 11 or 20 weeks old. Analysis of monoamine concentration in the hippocampus revealed that tryptophan, the serotonin metabolite 5-hydroxyindole acetic acid (5-HIAA), and the dopamine metabolite homovanillic acid (HVA) were significantly increased in 20-week-old IL-1Ra KO mice compared to littermate WT mice. These findings strongly suggest that the anxiety-like behavior observed in older mice was caused by the complicated alteration of monoamine metabolism and/or GR expression in the hippocampus., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)
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- 2015
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25. Methamphetamine-sensitized rats show augmented dopamine release to methylphenidate stimulation: a positron emission tomography using [18F]fallypride.
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Ota M, Ogawa S, Kato K, Wakabayashi C, and Kunugi H
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- Animals, Benzamides, Biomarkers metabolism, Corpus Striatum diagnostic imaging, Corpus Striatum drug effects, Disease Models, Animal, Humans, Male, Positron-Emission Tomography methods, Rats, Receptors, Dopamine D2 metabolism, Schizophrenia diagnosis, Central Nervous System Stimulants pharmacology, Corpus Striatum metabolism, Dopamine metabolism, Methamphetamine pharmacology, Methylphenidate pharmacology, Schizophrenia metabolism
- Abstract
Previous studies demonstrated that patients with schizophrenia show greater sensitivity to psychostimulants than healthy subjects. Sensitization to psychostimulants and resultant alteration of dopaminergic neurotransmission in rodents have been suggested as a useful model of schizophrenia. This study was aimed to examine the use of methylphenidate as a psychostimulant to induce dopamine release and that of [18F]fallypride as a radioligand to estimate the release in a rat model of schizophrenia. Six rats were scanned by positron emission tomography (PET) twice before and after methylphenidate challenge to evaluate dopamine release. After the scans, these rats were sensitized by using repeated methamphetamine (MAP) administration. Then, they were re-scanned twice again before and after methylphenidate challenge to evaluate whether MAP-sensitized rats show greater sensitivity to methylphenidate. We revealed a main effect of MAP-pretreatment and that of metylphenidate challenge. We found that % change of distribution volume ratio after repeated administration of MAP was greater than that before sensitization. These results suggest that methylphenidate-induced striatal dopamine release increased after sensitization to MAP. PET scan using [18F]fallypride at methylphenidate-challenge may provide a biological marker for schizophrenia and be useful to diagnose schizophrenia., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)
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- 2015
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26. Chemomechanical coupling of human mitochondrial F1-ATPase motor.
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Suzuki T, Tanaka K, Wakabayashi C, Saita E, and Yoshida M
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- Adenosine Triphosphate metabolism, Azides pharmacology, Biocatalysis drug effects, Humans, Hydrolysis drug effects, Models, Molecular, Proton-Translocating ATPases antagonists & inhibitors, Rotation, Mitochondria enzymology, Proton-Translocating ATPases chemistry, Proton-Translocating ATPases metabolism
- Abstract
The rotary motor enzyme F1-ATPase (F1) is a catalytic subcomplex of FoF1-ATP synthase that produces most of the ATP in respiring cells. Chemomechanical coupling has been studied extensively for bacterial F1 but very little for mitochondrial F1. Here we report ATP-driven rotation of human mitochondrial F1. A rotor-shaft γ-subunit in the stator α3β3 ring rotates 120° per ATP with three catalytic steps: ATP binding to one β-subunit at 0°, inorganic phosphate (Pi) release from another β-subunit at 65° and ATP hydrolysis on the third β-subunit at 90°. Rotation is often interrupted at 90° by persistent ADP binding and is stalled at 65° by a specific inhibitor azide. A mitochondrial endogenous inhibitor for FoF1-ATP synthase, IF1, blocks rotation at 90°. These features differ from those of bacterial F1, in which both ATP hydrolysis and Pi release occur at around 80°, demonstrating that chemomechanical coupling angles of the γ-subunit are tuned during evolution.
- Published
- 2014
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27. Effect of L-theanine on sensorimotor gating in healthy human subjects.
- Author
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Ota M, Wakabayashi C, Matsuo J, Kinoshita Y, Hori H, Hattori K, Sasayama D, Teraishi T, Obu S, Ozawa H, and Kunugi H
- Subjects
- Adult, Dose-Response Relationship, Drug, Female, Glutamates blood, Habituation, Psychophysiologic drug effects, Healthy Volunteers, Humans, Male, Glutamates pharmacology, Prepulse Inhibition drug effects, Sensory Gating drug effects
- Abstract
Aim: l-Theanine (N-ethyl-l-glutamine) is an amino acid uniquely found in green tea. Growing evidence has suggested the possible effects of l-theanine on cognition. Previously, we found that l-theanine attenuates MK-801-induced deficit in prepulse inhibition (PPI) in mice. In this study, we examined the effect of l-theanine in increasing the PPI in healthy humans., Methods: The subjects were 14 healthy adults who underwent PPI testing as a measure of sensorimotor gating 90 min after an oral intake of l-theanine (0, 200, 400, or 600 mg). PPI tests were done by examiners who were blind to the dose., Results: The administration of 200 mg of l-theanine and that of 400 mg, but not 600 mg, significantly increased the % PPI compared to the baseline (0 mg). There was no significant relation between the dose of l-theanine and the startle magnitude or the habituation of startle response. The plasma concentrations of l-theanine correlated with the dose of l-theanine., Conclusion: The observed effect with 200-400 mg of l-theanine on PPI suggested that l-theanine at a particular dose range increases sensorimotor gating in humans., (© 2013 The Authors. Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology.)
- Published
- 2014
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28. Cd72(c) is a modifier gene that regulates Fas(lpr)-induced autoimmune disease.
- Author
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Xu M, Hou R, Sato-Hayashizaki A, Man R, Zhu C, Wakabayashi C, Hirose S, Adachi T, and Tsubata T
- Subjects
- Animals, Antigens, CD immunology, Antigens, Differentiation, B-Lymphocyte immunology, Autoantibodies immunology, B-Lymphocytes immunology, B-Lymphocytes metabolism, Cell Line, Female, Immunophenotyping, Lupus Erythematosus, Systemic genetics, Lupus Erythematosus, Systemic immunology, Lymph Nodes cytology, Mice, Mice, Congenic, Mice, Inbred MRL lpr, Mice, Knockout, Mutation, Receptors, Antigen, B-Cell metabolism, Signal Transduction, Spleen cytology, fas Receptor immunology, Antigens, CD genetics, Antigens, Differentiation, B-Lymphocyte genetics, Autoimmune Diseases genetics, Autoimmune Diseases immunology, Gene Expression Regulation, fas Receptor genetics
- Abstract
Although modifier genes are extensively studied in various diseases, little is known about modifier genes that regulate autoimmune diseases. Autoimmune disease caused by the Fas(lpr) mutation depends on the genetic background of mouse strains, suggesting a crucial role of modifier genes. MRL/MpJ-Fas(lpr) (MRL/lpr) and AKR/lpr mice develop severe and mild lupus-like autoimmune disease, respectively, whereas this mutation does not cause disease on C57BL/6 (B6) or C3H background. Both MRL and AKR carry the same haplotype of the Cd72 gene encoding an inhibitory BCR coreceptor (CD72(c)), and CD72(c) contains several amino acid substitutions and a deletion in the extracellular region compared with CD72(a) and CD72(b). To address the role of Cd72(c) locus in the regulation of Fas(lpr)-induced autoimmune disease, we generated B6.CD72(c)/lpr and MRL.CD72(b)/lpr congenic mice. Introduction of the chromosomal interval containing Cd72(c) did not cause disease in B6 mice by itself, but caused development of lupus-like disease in the presence of Fas(lpr) on B6 background, clearly demonstrating that this interval contains the modifier gene that regulates Fas(lpr)-induced autoimmune disease. Conversely, MRL.CD72(b)/lpr congenic mice showed milder disease compared with MRL/lpr mice. We further demonstrated that Cd72(c) is a hypofunctional allele in BCR signal inhibition and that CD72 deficiency induces severe autoimmune disease in the presence of Fas(lpr). These results strongly suggest that the Cd72(c) is a crucial modifier gene that regulates Fas(lpr)-induced autoimmune disease due to its reduced activity of B cell signal regulation.
- Published
- 2013
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29. Increased cerebrospinal fluid interleukin-6 levels in patients with schizophrenia and those with major depressive disorder.
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Sasayama D, Hattori K, Wakabayashi C, Teraishi T, Hori H, Ota M, Yoshida S, Arima K, Higuchi T, Amano N, and Kunugi H
- Subjects
- Adult, Depressive Disorder, Major blood, Female, Humans, Interleukin-6 blood, Male, Middle Aged, Schizophrenia blood, Statistics, Nonparametric, Depressive Disorder, Major cerebrospinal fluid, Depressive Disorder, Major complications, Interleukin-6 cerebrospinal fluid, Schizophrenia cerebrospinal fluid, Schizophrenia complications
- Abstract
Elevated peripheral levels of interleukin-6 (IL-6) are common findings in schizophrenia and depression. However, previous studies that measured cerebrospinal fluid (CSF) IL-6 levels in these disorders reported controversial results. The present study examined whether CSF IL-6 levels are altered in patients with schizophrenia and those with depression. Lumbar punctures were performed in 32 patients with schizophrenia, 30 with major depressive disorder (MDD), and 35 healthy controls. Serum samples were simultaneously collected from all subjects in the patient groups and from 32 of the control group. CSF and serum IL-6 levels were determined by enzyme-linked immunosorbent assay. Both the patients with schizophrenia and MDD had significantly higher CSF IL-6 levels compared to the controls (schizophrenia: P = 0.0027; MDD: P = 0.012). IL-6 levels were significantly higher in the CSF than in the serum. No significant correlation was observed between CSF and serum IL-6 levels. The present findings suggest that IL-6 of central origin is associated with the pathophysiology of schizophrenia and MDD, although confounding effect of smoking status can not be entirely excluded., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2013
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30. Chronic restraint stress causes anxiety- and depression-like behaviors, downregulates glucocorticoid receptor expression, and attenuates glutamate release induced by brain-derived neurotrophic factor in the prefrontal cortex.
- Author
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Chiba S, Numakawa T, Ninomiya M, Richards MC, Wakabayashi C, and Kunugi H
- Subjects
- Animals, Anxiety blood, Anxiety complications, Anxiety physiopathology, Behavior, Animal physiology, Brain-Derived Neurotrophic Factor pharmacology, Depression blood, Depression complications, Depression physiopathology, Disease Models, Animal, Down-Regulation, Glucocorticoids blood, Male, Nerve Tissue Proteins, Prefrontal Cortex drug effects, Prefrontal Cortex physiopathology, Rats, Rats, Wistar, Receptor, trkB metabolism, Receptors, Growth Factor, Receptors, Nerve Growth Factor metabolism, Stress, Psychological blood, Stress, Psychological complications, Stress, Psychological physiopathology, Anxiety metabolism, Brain-Derived Neurotrophic Factor metabolism, Depression metabolism, Glutamic Acid metabolism, Prefrontal Cortex metabolism, Receptors, Glucocorticoid metabolism, Restraint, Physical methods, Restraint, Physical physiology, Restraint, Physical psychology, Stress, Psychological metabolism
- Abstract
Stress and the resulting increase in glucocorticoid levels have been implicated in the pathophysiology of depressive disorders. We investigated the effects of chronic restraint stress (CRS: 6 hours × 28 days) on anxiety- and depression-like behaviors in rats and on the possible changes in glucocorticoid receptor (GR) expression as well as brain-derived neurotrophic factor (BDNF)-dependent neural function in the prefrontal cortex (PFC). We observed significant reductions in body weight gain, food intake and sucrose preference from 1 week after the onset of CRS. In the 5th week of CRS, we conducted open-field (OFT), elevated plus-maze (EPM) and forced swim tests (FST). We observed a decrease in the number of entries into open arms during the EPM (anxiety-like behavior) and increased immobility during the FST (depression-like behavior). When the PFC was removed after CRS and subject to western blot analysis, the GR expression reduced compared with control, while the levels of BDNF and its receptors remained unchanged. Basal glutamate concentrations in PFC acute slice which were measured by high performance liquid chromatography were not influenced by CRS. However, BDNF-induced glutamate release was attenuated after CRS. These results suggest that reduced GR expression and altered BDNF function may be involved in chronic stress-induced anxiety--and depression-like behaviors., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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31. Effect of stamped reply envelopes and timing of newsletter delivery on response rates of mail survey: a randomised controlled trial in a prospective cohort study.
- Author
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Wakabayashi C, Hayashi K, Nagai K, Sakamoto N, and Iwasaki Y
- Abstract
Objective: To examine the effects of stamped reply envelope and the timing of newsletter distribution., Design: A randomised controlled trial in a prospective cohort study with a 2×2 factorial design of two interventions., Setting: The Japan Nurses' Health Study (JNHS), a prospective cohort study for women's health., Participants: The present study included 6938 women who were part of the first-year entry cohort for the fifth wave of the biannual follow-up survey of the JNHS., Intervention: The participants were randomly allocated into four groups; Group-1 (business-reply, newsletter with initial mailing), Group-2 (business-reply, newsletter with reminder), Group-3 (stamped envelopes, newsletter with initial mailing) and Group-4 (stamped envelopes, newsletter with reminder). The thank-you and reminder letters were mailed out at the end of the sixth week. This study was censored at the end of 12 weeks., Main Outcome Measures: Main outcome measures were cumulative response at the end of 6 and 12 weeks after mailing out the questionnaire., Results: The cumulative response at 12 weeks were 58.3% for Group-1, 54.1% for Group-2, 60.5% for Group-3 and 56.7% for Group-4 (p=0.001). The odds of the response was higher for stamped envelopes than for business-reply envelopes (OR (95% CI)=1.10(1.00 to 1.21)). The odds was higher for newsletter delivery with initial mailing than for with reminder (1.18(1.07 to 1.29)). The response in first 6 weeks for stamped envelope was significantly higher than for business-reply envelope (p=0.047). Although the response in 6 weeks for women received the newsletter with initial mailing was lower than for women who did not, the proportions did not differ significantly (p=0.291)., Conclusions: The style of return envelope affected response rates of mail survey. The results of this study suggest that practices of provision of the additional information, should be handled individually in advance, as a separate event from sending follow-up questionnaire or reminder letters.
- Published
- 2012
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32. Behavioral and molecular evidence for psychotropic effects in L-theanine.
- Author
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Wakabayashi C, Numakawa T, Ninomiya M, Chiba S, and Kunugi H
- Subjects
- Animals, Calcium metabolism, Dizocilpine Maleate pharmacology, Gene Expression Regulation drug effects, Glutamates administration & dosage, Hippocampus drug effects, Hippocampus metabolism, Male, Maze Learning drug effects, Mice, Mice, Inbred C57BL, Reflex, Startle drug effects, Behavior, Animal drug effects, Brain-Derived Neurotrophic Factor genetics, Glutamates pharmacology, Receptors, N-Methyl-D-Aspartate agonists
- Abstract
Rationale: L-Theanine (N-ethyl-L: -glutamine) is an amino acid uniquely found in green tea and historically considered to be a relaxing agent. It is a glutamate derivative and has an affinity for glutamatergic receptors. However, its psychotropic effects remain unclear., Objectives: To elucidate effects of L: -theanine on psychiatric disease-related behaviors in mice and its molecular basis focusing on brain-derived neurotrophic factor (BDNF) and N-methyl-D: -aspartate (NMDA) receptor., Methods: We examined the effects of L: -theanine on behaviors in mice by using the open-field test (OFT), forced swim test (FST), elevated plus-maze test (EPMT), and prepulse inhibition (PPI) of acoustic startle. By western blot analysis, we looked at the effect of L: -theanine on the expression of BDNF and related proteins in the hippocampus and cerebral cortex. To determine whether L: -theanine has agonistic action on the NMDA receptor, we performed Fluo-3 intracellular Ca(2+) imaging in cultured cortical neurons., Results: Single administration of L: -theanine significantly attenuated MK-801-induced deficits in PPI. Subchronic administration (3-week duration) of L: -theanine significantly reduced immobility time in the FST and improved baseline PPI. Western blotting analysis showed increased expression of BDNF protein in the hippocampus after subchronic administration of L: -theanine. In cultured cortical neurons, L: -theanine significantly increased the intracellular Ca(2+) concentration, and this increase was suppressed by competitive and non-competitive NMDA receptor antagonists (AP-5 and MK-801, respectively)., Conclusions: Our results suggest that L: -theanine has antipsychotic-like and possibly antidepressant-like effects. It exerts these effects, at least in part, through induction of BDNF in the hippocampus and the agonistic action of L: -theanine on the NMDA receptor.
- Published
- 2012
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33. Association of plasma IL-6 and soluble IL-6 receptor levels with the Asp358Ala polymorphism of the IL-6 receptor gene in schizophrenic patients.
- Author
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Sasayama D, Wakabayashi C, Hori H, Teraishi T, Hattori K, Ota M, Ishikawa M, Arima K, Higuchi T, Amano N, and Kunugi H
- Subjects
- Adult, Case-Control Studies, Female, Genetic Predisposition to Disease, Genotype, Humans, Male, Middle Aged, Polymorphism, Genetic, Risk Factors, Schizophrenia blood, Interleukin-6 blood, Receptors, Interleukin-6 blood, Receptors, Interleukin-6 genetics, Schizophrenia genetics, Schizophrenia immunology
- Abstract
Recent studies indicate a role of excessive interleukin-6 (IL-6) signaling in the pathogenesis of schizophrenia. A previous study reported a significant association of schizophrenia with the IL-6 receptor (IL-6R) gene Asp358Ala polymorphism, which is known to regulate circulating IL-6 and soluble IL-6R (sIL-6R) levels in healthy subjects. To further examine the influence of the polymorphism in schizophrenic patients, we compared the plasma levels of IL-6 and sIL-6R between schizophrenic patients and healthy controls for each genotype of the Asp358Ala polymorphism. Asp358Ala genotyping and plasma IL-6 level measurements were performed in 104 patients with schizophrenia and 112 healthy controls. Of these participants, 53 schizophrenic patients and 49 controls were selected for the measurement of plasma sIL-6R levels. A two-way factorial analysis of covariance was performed with the transformed plasma levels as the dependent variable, diagnosis and genotype as independent variables, and sex and age as covariates. No significant diagnosis × genotype interaction was observed for IL-6 and sIL-6R levels. The Ala allele of Asp358Ala was significantly associated with higher levels of both IL-6 and sIL-6R. IL-6 levels were significantly elevated in schizophrenic patients compared to those in controls, whereas no significant difference in sIL-6R levels was observed between schizophrenic patients and controls. Our findings suggest that the presence of schizophrenia is associated with elevated IL-6 levels, whereas sIL-6R levels are mainly predetermined by the Asp358Ala genotype and are not associated with the disease status. Increased IL-6 levels without alterations in sIL-6R levels may result in excessive IL-6 signaling in schizophrenia., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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34. Expression of Ca²⁺-dependent activator protein for secretion 2 is increased in the brains of schizophrenic patients.
- Author
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Hattori K, Tanaka H, Wakabayashi C, Yamamoto N, Uchiyama H, Teraishi T, Hori H, Arima K, and Kunugi H
- Subjects
- Adult, Aged, Animals, Antipsychotic Agents pharmacology, Autopsy, Brain metabolism, Calcium-Binding Proteins blood, Calcium-Binding Proteins metabolism, Cerebral Cortex metabolism, Female, Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) physiology, Humans, Male, Mental Disorders metabolism, Mice, Mice, Inbred C57BL, Middle Aged, Protein Isoforms genetics, RNA blood, Risperidone pharmacology, Schizophrenia epidemiology, Schizophrenia physiopathology, TATA-Box Binding Protein physiology, Time Factors, Vesicular Transport Proteins blood, Vesicular Transport Proteins metabolism, Brain physiopathology, Calcium-Binding Proteins biosynthesis, Calcium-Binding Proteins genetics, Cerebral Cortex physiopathology, Mental Disorders physiopathology, Protein Isoforms biosynthesis, Schizophrenia metabolism, Vesicular Transport Proteins biosynthesis, Vesicular Transport Proteins genetics
- Abstract
Ca(2+)-dependent activator protein for secretion 2 (CADPS2), a secretory granule associate protein, mediates monoamine transmission and the release of neurotrophins including brain-derived neurotrophic factor (BDNF) which have been implicated in psychiatric disorders. Furthermore, the expression of CADPS2deltaExon3, a defective splice variant of CADPS2, has been reported to be associated with autism. Based on these observations, we examined whether expression levels of CADPS2 and CADPS2deltaExon3 are altered in psychiatric disorders. Quantitative polymerase chain reaction analysis was performed for postmortem frontal cortex tissues (BA6) from 15 individuals with schizophrenia, 15 with bipolar disorder, 15 with major depression, and 15 controls (Stanley neuropathology consortium). The mean CADPS2 expression levels normalized to human glyceraldehyde-3phosphate dehydrogenase (GAPDH) or TATA-box binding protein levels was found to be significantly increased in the brains of the schizophrenia group, compared to the control group. On the other hand, the ratio of CADPS2deltaExon3 to total CADPS2 was similar in the 4 diagnostic groups. We then analyzed CADPS2 expression in blood samples from 121 patients with schizophrenia and 318 healthy controls; however, there was no significant difference between the two groups. Chronic risperidone treatment did not alter the expression of CADPS2 in frontal cortex of mice. The observed increase in the expression of CADPS2 may be related to the impaired synaptic function in schizophrenia., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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35. Modulation of nucleotide specificity of thermophilic F(o)F(1)-ATP Synthase by epsilon-subunit.
- Author
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Suzuki T, Wakabayashi C, Tanaka K, Feniouk BA, and Yoshida M
- Subjects
- Adenosine Triphosphate chemistry, Bacillus enzymology, Chromatography, High Pressure Liquid methods, Escherichia coli enzymology, Fluorescence Resonance Energy Transfer methods, Guanosine Triphosphate chemistry, Hydrolysis, Nucleotides genetics, Protein Conformation, Protein Subunits chemistry, Substrate Specificity, Temperature, ATPase Inhibitory Protein, Nucleotides chemistry, Proteins chemistry, Proton-Translocating ATPases chemistry
- Abstract
The C-terminal two α-helices of the ε-subunit of thermophilic Bacillus F(o)F(1)-ATP synthase (TF(o)F(1)) adopt two conformations: an extended long arm ("up-state") and a retracted hairpin ("down-state"). As ATP becomes poor, ε changes the conformation from the down-state to the up-state and suppresses further ATP hydrolysis. Using TF(o)F(1) expressed in Escherichia coli, we compared TF(o)F(1) with up- and down-state ε in the NTP (ATP, GTP, UTP, and CTP) synthesis reactions. TF(o)F(1) with the up-state ε was achieved by inclusion of hexokinase in the assay and TF(o)F(1) with the down-state ε was represented by εΔc-TF(o)F(1), in which ε lacks C-terminal helices and hence cannot adopt the up-state under any conditions. The results indicate that TF(o)F(1) with the down-state ε synthesizes GTP at the same rate of ATP, whereas TF(o)F(1) with the up-state ε synthesizes GTP at a half-rate. Though rates are slow, TF(o)F(1) with the down-state ε even catalyzes UTP and CTP synthesis. Authentic TF(o)F(1) from Bacillus cells also synthesizes ATP and GTP at the same rate in the presence of adenosine 5'-(β,γ-imino)triphosphate (AMP-PNP), an ATP analogue that has been known to stabilize the down-state. NTP hydrolysis and NTP-driven proton pumping activity of εΔc-TF(o)F(1) suggests similar modulation of nucleotide specificity in NTP hydrolysis. Thus, depending on its conformation, ε-subunit modulates substrate specificity of TF(o)F(1).
- Published
- 2011
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36. Quantitative assessment of left ventricular and left atrial functions by strain rate imaging in diabetic patients with and without hypertension.
- Author
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Muranaka A, Yuda S, Tsuchihashi K, Hashimoto A, Nakata T, Miura T, Tsuzuki M, Wakabayashi C, Watanabe N, and Shimamoto K
- Subjects
- Female, Humans, Hypertension complications, Male, Middle Aged, Models, Biological, Models, Statistical, Reproducibility of Results, Sensitivity and Specificity, Ventricular Dysfunction, Left complications, Atrial Function, Left, Diabetes Complications diagnostic imaging, Echocardiography methods, Elasticity Imaging Techniques methods, Hypertension diagnostic imaging, Ventricular Dysfunction, Left diagnostic imaging
- Abstract
Background: Impaired left ventricular (LV) function is shown by strain rate (SR) imaging in patients with diabetes mellitus (DM). Left atrium (LA) function in patients with DM, however, has not been assessed by this method and the effect of hypertension (HT) on LV and LA functions in diabetic patients has not been fully studied. The aim of this study was to quantitatively assess LA function in diabetic patients with and without HT in combination with LV function., Methods: Conventional echocardiographic and SR imaging studies were performed in 55 subjects with normal systolic LV function (LV ejection fraction of 55% or more) and no evidence of coronary artery disease: 17 with DM (DM group), 22 who have both DM and HT (DM+HT group), and 16 age-matched controls. SR imaging was performed from three apical views, and peak SR was measured at 12 LV segments and 5 LA segments. Mean peak systolic SR (LVs and LAs, respectively), early diastolic SR (LVe and LAe, respectively) and late diastolic SR (LVa and LAa, respectively) were calculated by averaging data in each LV and LA segment., Results: Despite no significant differences in age, LV ejection fraction and E/A ratio among the three groups, systolic blood pressure, LA dimension and LV mass index in the DM+HT group were significantly larger than those in the controls. The DM group had reduced systolic and diastolic LV functions and impaired LA reservoir and conduit functions compared with those in the controls, as shown by lower LVs (P < 0.05), LVe (P < 0.01), LAs (P < 0.01), and LAe (P < 0.05). The DM+HT group had reduced LVs (P < 0.01), LVe (P < 0.01), LAs (P < 0.01) and LAe (P < 0.01) compared with those in the controls. The DM+HT group had significantly lower LVe (P < 0.05) and LAe (P < 0.05) than did the DM group., Conclusions: SR imaging can detect impairment of LA reservoir and conduit functions as well as LV systolic and diastolic dysfunctions in patients with DM, even in the absence of LV hypertrophy and LA dilatation. Coexisting HT augments the impairment of LV diastolic and LA conduit functions in diabetic patients.
- Published
- 2009
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37. Discriminating between silent cerebral infarction and deep white matter hyperintensity using combinations of three types of magnetic resonance images: a multicenter observer performance study.
- Author
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Sasaki M, Hirai T, Taoka T, Higano S, Wakabayashi C, Matsusue E, and Ida M
- Subjects
- Aged, Aged, 80 and over, Cerebral Infarction pathology, Cerebral Infarction physiopathology, Diagnosis, Differential, False Positive Reactions, Female, Humans, Image Interpretation, Computer-Assisted, Male, Middle Aged, Observer Variation, Predictive Value of Tests, Reproducibility of Results, Cerebral Infarction diagnosis, Magnetic Resonance Imaging methods
- Abstract
Introduction: We attempted to determine the most appropriate combination of magnetic resonance (MR) images that can accurately detect and discriminate between asymptomatic infarction and deep white matter hyperintensity (DWMH); these lesions have different clinical implications and are occasionally confused., Materials and Methods: We performed an observer performance analysis using cerebral MR images of 45 individuals with or without asymptomatic small white matter infarction and/or mild DWMH who participated in a physical checkup program at four institutions. Six observers interpreted whether infarction and/or DWMH existed in combinations of two or three image types of the T1-weighted images (T1WI), T2-weighted images (T2WI), and fluid-attenuated inversion recovery (FLAIR) images. The observers' performance was evaluated with a receiver operating characteristic (ROC) analysis., Results: The averaged area under the ROC curve (Az) for detecting a infarction was significantly larger in the combination of all the three image types (0.95) than that in any combinations of the two image types (T1WI and FLAIR images, 0.87; T2WI and FLAIR images, 0.85; T1WI and T2WI, 0.86). The Az for detecting DWMH was significantly smaller in the combination of T1WI and T2WI (0.79) than that in other image combinations (T1WI and FLAIR, 0.89; T2WI and FLAIR, 0.91; T1WI, T2WI, and FLAIR, 0.90)., Conclusion: The combination of T1WI, T2WI, and FLAIR images is required to accurately detect both small white matter infarction and mild DWMH.
- Published
- 2008
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38. [A nationwide survey for implementation of Health Japan 21 anti-smoking countermeasures in municipalities throughout Japan].
- Author
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Shinmura H, Wakabayashi C, Kunisawa N, Kayaba K, Miura Y, Ojima T, and Yanagawa H
- Subjects
- Adolescent, Adult, Child, Humans, Japan, Health Promotion methods, Smoking Cessation methods
- Abstract
Purpose: Smoking cessation is one of the most important items for improvement of health in Japan. The Japanese government started a new campaign called the "Health Japan 21" to promote better health of Japanese citizens in the 21st century. The purpose of the present study was to observe the situation of the municipalities throughout Japan regarding implementation of anti-smoking countermeasures and setting of the level of target values to be achieved over the next ten years., Methods: Mail questionnaire forms were sent to 953 municipalities which had formulated specific local plans for the promotion of health. Of this total, 793 (83.2%) responded to the inquiry., Results: The most commonly implemented countermeasure against smoking was restricting smoking only to limited areas in municipality offices (75%), followed by providing support for stopping smoking (35%), and providing a complete smoke free environment in municipality offices (32.4%). Proportions of local governments putting a ban on smoking on public roads (7.5%), giving publicity to restaurants with smoking restrictions (< 5%) and setting no smoking times in the municipality offices (< 5%) were low. Some 70% of municipalities provided anti-smoking education for school children. Very few local governments took measures such as identifying age at purchasing tobacco, removing vending machines and restricting tobacco advertisement., Conclusion: Most municipalities have made much of anti-smoking activities. However, measures for school children were not satisfactorily implemented. The execution rates for anti-smoking activities are low in small-scale municipalities and therefore it is necessary to provide particular support in these cases.
- Published
- 2008
39. [Family influences on future smoking habits among junior high school students in Japan].
- Author
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Wakabayashi C
- Subjects
- Adolescent, Attitude, Cross-Sectional Studies, Female, Health Behavior, Humans, Japan, Male, Mothers, Psychology, Adolescent, Family, Smoking psychology
- Abstract
Objective: To examine the effects of health-related behavior and family smoking habits on the future smoking habits of junior high school students in two Japanese cities with different life expectancies., Methods: A cross-sectional study was conducted in January 2005 of all second-grade students in a junior high school in city A located in Aomori prefecture (399 students) and city B located in Nagano prefecture (447 students). Life expectancies in city B were 4.2 years longer in men and 2.9 years longer in women than in city A. Data on feelings about future smoking habits, dislike of tobacco smoke, family smoking habits and health-related behavior were collected., Results: The proportion of boys who went on to become smokers was higher in city A (18.7%) than in city B (10.3%). The proportions of smoking mothers and other smoking family members were also higher in city A, while the proportion of students who disliked tobacco smoke was lower. For girls in both cities, there was a significant positive association between future smoking and maternal smoking., Conclusion: The findings suggest that maternal smoking habits are especially strongly correlated with future smoking in girls. The family smoking environment and health-related behavior should therefore be considered in measures to prevent smoking by students.
- Published
- 2007
40. [Implementation and evaluation of local planning of Healthy Japan 21].
- Author
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Wakabayashi C
- Subjects
- Health Care Surveys, Japan, Health Promotion methods, Local Government
- Published
- 2007
41. Noninvasive assessment of left atrial function by strain rate imaging in patients with hypertension: a possible beneficial effect of renin-angiotensin system inhibition on left atrial function.
- Author
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Kokubu N, Yuda S, Tsuchihashi K, Hashimoto A, Nakata T, Miura T, Ura N, Nagao K, Tsuzuki M, Wakabayashi C, and Shimamoto K
- Subjects
- Aged, Angiotensin II Type 1 Receptor Blockers therapeutic use, Angiotensin-Converting Enzyme Inhibitors therapeutic use, Feasibility Studies, Female, Humans, Hypertension drug therapy, Hypertrophy, Left Ventricular diagnostic imaging, Hypertrophy, Left Ventricular physiopathology, Male, Middle Aged, Reproducibility of Results, Atrial Function, Left drug effects, Echocardiography methods, Hypertension diagnostic imaging, Hypertension physiopathology, Models, Cardiovascular, Renin-Angiotensin System drug effects
- Abstract
Renin-angiotensin system (RAS) inhibitors are likely to reduce the development of atrial fibrillation by preventing atrial fibrosis. Strain rate (SR) imaging is a novel echocardiographic technique to quantify left atrial (LA) function. However, it has not been determined whether SR imaging is applicable for detection of LA dysfunction in hypertensive (HT) patients. We used SR imaging to assess alteration in LA function in HT patients and its modification by RAS inhibitors. SR imaging was performed in 80 HT patients and 50 age-matched normotensive (NT) subjects. HT patients were divided into two groups according to left ventricular hypertrophy (LVH) and LA dilatation. Peak SR was measured at each LA segment (septal, lateral, posterior, anterior, and inferior) and mean peak systolic SR (SR-LAs) was calculated by averaging data in each segment. Mean SR-LAs levels in the dilated LA group (1.97+/-0.45 s(-1), n=25) and non-dilated LA group (2.15+/-0.57 s(-1), n=55) were significantly (p<0.05) lower than that in NT subjects (2.53+/-0.71 s(-1)). Irrespective of the presence or absence of LVH, mean SR-LAs in HT patients was lower than that in NT subjects. When RAS inhibitors were used, the mean SR-LAs level in the non-dilated LA group was equivalent to that in NT subjects. In HT patients, mean SR-LAs, an index of LA reservoir function, decreases before development of LA enlargement and LVH. Treatment with RAS inhibitors appears to preserve LA reservoir function in HT patients without dilated LA. SR imaging can detect LA dysfunction in HT patients and is useful for evaluation of the therapeutic benefit on LA reservoir function.
- Published
- 2007
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42. The intent and practice of condom use among HIV-positive men who have sex with men in Japan.
- Author
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Inoue Y, Yamazaki Y, Kihara M, Wakabayashi C, Seki Y, and Ichikawa S
- Subjects
- Adult, Anti-HIV Agents therapeutic use, Antiretroviral Therapy, Highly Active, HIV Infections drug therapy, HIV Infections psychology, HIV Infections transmission, Homosexuality, Male psychology, Humans, Japan, Male, Multivariate Analysis, Safe Sex psychology, Surveys and Questionnaires, Condoms statistics & numerical data, HIV Infections prevention & control, Homosexuality, Male statistics & numerical data, Safe Sex statistics & numerical data
- Abstract
To evaluate the intent and practice of condom use among Japanese HIV-positive men who have sex with men (MSM), a survey using anonymous questionnaires was carried out and 117 respondents were investigated. For anal sex and oral sex, respectively, 58.1% and 15.2% intended to use condoms and 47.2% and 12.4% used condoms all of the time. The intent of condom use decisively affected the practice of condom use and was closely related to the perceived risk level of HIV/sexually transmitted (STI) transmission. In anal sex, willingness to protect sexual partners from HIV infection was strongly related not only to the intent but also to the practice. Enhancement of willingness to protect oneself from STI was suggested to enhance willingness to protect his/her sexual partners from HIV infection with secondary enhancement of the intent or the practice of condom use. Specific support of MSM with HIV for improving the intent and practice of condom use is urgently needed.
- Published
- 2006
- Full Text
- View/download PDF
43. Persistent insulin-sensitizing effects of sarpogrelate hydrochloride, a serotonin 2A receptor antagonist, in patients with peripheral arterial disease.
- Author
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Kokubu N, Tsuchihashi K, Yuda S, Hase M, Eguchi M, Wakabayashi T, Hashimoto A, Nakata T, Miura T, Ura N, Nagao K, Tsuzuki M, Wakabayashi C, and Shimamoto K
- Subjects
- Adiponectin blood, Aged, Aged, 80 and over, Atherosclerosis drug therapy, Atherosclerosis physiopathology, Blood Pressure drug effects, Blood Pressure physiology, Female, Homeostasis physiology, Humans, Male, Middle Aged, Peripheral Vascular Diseases blood, Serotonin 5-HT2 Receptor Antagonists, Serotonin Antagonists pharmacology, Succinates pharmacology, Insulin Resistance physiology, Peripheral Vascular Diseases drug therapy, Peripheral Vascular Diseases physiopathology, Serotonin Antagonists therapeutic use, Succinates therapeutic use
- Abstract
Background: There is considerable interest in the pleiotropic pharmacological action of sarpogrelate hydrochloride, a novel selective serotonin 2A receptor antagonist. In the present study the persistent insulin-sensitizing effects of sarpogrelate were investigated in non-diabetic and non-medicated diabetic patients with peripheral artery disease (PAD)., Methods and Results: Indices of insulin resistance (IR) (fasting immunoreactive insulin (IRI) and calculated homeostasis model assessment (HOMA-R)) and adiponectin were measured before and after 2 weeks of sarpogrelate administration (300 mg/day) in 24 patients (19 men, 76+/-9 years) with PAD. Sixteen of the 24 patients were examined after 3 months of treatment for assessment of the chronic effect of sarpogrelate on IR. After 2 weeks of treatment, significant decreases in fasting IRI (p=0.03) and HOMA-R (p=0.024), but not in adiponectin, were observed. After 3 months of treatment, significant decreases in fasting IRI (16.0+/-10.3 vs 9.2+/-2.0 microU/ml, p=0.03) and HOMA-R (4.30+/-2.83 vs 2.40+/-0.74, p=0.025) were maintained. Furthermore, adiponectin was significantly increased (8.11+/-4.13 vs 9.64+/-4.37 microg/ml, p=0.027). All of the examined HOMA-R had a significant correlation with all of the examined adiponectin (p<0.001, r=-0.441)., Conclusions: Sarpogrelate has a persistent insulin-sensitizing effect through adiponectin modification and might be beneficial for anti-atherosclerotic therapy, at least, in non-diabetic and non-medicated diabetic patients with PAD.
- Published
- 2006
- Full Text
- View/download PDF
44. Does caregiving increase poverty among women in later life? Evidence from the Health and Retirement survey.
- Author
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Wakabayashi C and Donato KM
- Subjects
- Aged, Data Collection, Female, Geriatric Nursing, Humans, Long-Term Care, Middle Aged, Risk Assessment, United States, Caregivers economics, Poverty, Retirement economics
- Abstract
Given the rapid aging of the U.S. population and reductions in federal funding, elder care has become a major issue for many families. This paper focuses on a long-term consequence of elder care by asking how caring for elderly parents affects women's subsequent risks of living in poverty. Using longitudinal data from the Health and Retirement Study, we examine whether and how caregiving for parents in 1991 increases women's risks of living in households with incomes less than the poverty threshold, receiving public assistance, and receiving Medicaid in 1999. Our findings illustrate that caregiving in earlier life raises women's poverty risks in later life by intensifying the negative effects of stopping work and declining health on women's economic well-being.
- Published
- 2006
- Full Text
- View/download PDF
45. Implementation of a smoke-free policy on school premises and tobacco control as a priority among municipal health promotion activities: nationwide survey in Japan.
- Author
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Kayaba K, Wakabayashi C, Kunisawa N, Shinmura H, and Yanagawa H
- Subjects
- Adolescent, Adult, Bias, Cause of Death, Cross-Sectional Studies, Data Collection standards, Faculty, Health Priorities, Humans, Japan epidemiology, Life Expectancy, Logistic Models, Lung Neoplasms etiology, Lung Neoplasms mortality, Lung Neoplasms prevention & control, Male, Multivariate Analysis, Nonlinear Dynamics, Organizational Policy, Population Density, Program Evaluation, Public Health, Surveys and Questionnaires, Tobacco Smoke Pollution statistics & numerical data, Health Policy, Health Promotion organization & administration, Local Government, Schools organization & administration, Tobacco Smoke Pollution prevention & control
- Abstract
We conducted a nationwide survey to evaluate the effect of implementing a smoke-free policy in municipalities that forbid teachers to smoke on school premises. Questionnaires were mailed to 3207 municipalities throughout Japan. After we adjusted for population size and the standardized mortality ratio for male lung cancer, we found that assigning a high priority to tobacco control in municipal health promotion activities was significantly associated with implementation of school tobacco-control policies (odds ratio = 1.50, 95% confidence interval=1.24, 1.81).
- Published
- 2005
- Full Text
- View/download PDF
46. [A nationwide survey of municipalities' policy for smoking control and its implementation in relation to its priority grading by public health officers].
- Author
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Shinmura H, Kayaba K, Kunisawa N, Wakabayashi C, and Yanagawa H
- Subjects
- Health Education, Humans, Japan, Health Priorities, Public Health Practice, Smoking Cessation legislation & jurisprudence
- Abstract
Purpose: The purpose of this study was to investigate the present situation regarding implementation of smoking control programs and to clarify relations with public health officers' attitudes toward smoking control measures., Methods: A questionnaire form was mailed to the 3,207 local municipalities throughout Japan. The items included in the form were the contents of the smoking control programs, educational activities for passive smoking prevention, interaction with the media to spread education and awareness, and public health officers' attitudes toward smoking control measures., Results: Of 3,207 municipalities, 2,570 (80.1%) responded. Over 95% of local municipalities were undertaking smoking control programs. Among the programs carried out in practice, dividing areas into smoking and non-smoking sections in local government office buildings had the highest proportion of support (80%). On the other hand, complete prohibition of smoking in local government office buildings and non-smoking support programs were conducted by less than 20%. The dissemination of education activities were executed in 60 percent of government office buildings, and 36% of schools, but only 20% of athletic gyms, hospitals, and other facilities. Sixty percent of public health officers recognized the importance of smoking control programs. A non-smoking support program and complete prohibition of smoking in government office buildings were more likely to be executed in for local municipalities with a higher priority for smoking control programs. No significant association was found between attitudes regarding program importance and the division of areas into smoking and non-smoking sections in government office buildings., Conclusions: Our results suggest that promotion of smoking control measures in local municipalities may be dependent on the public health officers' attitude toward the issues. High priority should be given to assisting public health officials and other key personnel in recognizing the importance of implementing smoking control measures for attaining better health.
- Published
- 2004
47. [A case of traumatic sinus pericranii communicating to superior sagittal sinus demonstrated by MRI with Gd-DTPA administration].
- Author
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Ikeda N, Ikeda N, Wakabayashi S, Nagao K, Srivatanakul K, Ichioka T, Wakabayashi C, Kajikawa H, and Kuroiwa T
- Subjects
- Child, Contrast Media, Female, Humans, Sinus Pericranii etiology, Brain Injuries complications, Cranial Sinuses pathology, Gadolinium DTPA, Magnetic Resonance Imaging, Sinus Pericranii diagnosis
- Published
- 2003
48. A distinct signaling pathway used by the IgG-containing B cell antigen receptor.
- Author
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Wakabayashi C, Adachi T, Wienands J, and Tsubata T
- Subjects
- Animals, Antigens, CD metabolism, Antigens, Differentiation, B-Lymphocyte metabolism, B-Lymphocytes immunology, B-Lymphocytes metabolism, Calcium metabolism, Calcium Signaling, Cells, Cultured, Immunoglobulin D immunology, Immunoglobulin D metabolism, Immunoglobulin G chemistry, Immunoglobulin G immunology, Intracellular Signaling Peptides and Proteins, Lectins metabolism, Mice, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3, Mitogen-Activated Protein Kinases metabolism, Phosphorylation, Protein Tyrosine Phosphatase, Non-Receptor Type 6, Protein Tyrosine Phosphatases metabolism, Receptors, Antigen, B-Cell chemistry, Receptors, Antigen, B-Cell immunology, Sialic Acid Binding Ig-like Lectin 2, Transfection, Tumor Cells, Cultured, Cell Adhesion Molecules, Immunoglobulin G metabolism, Receptors, Antigen, B-Cell metabolism, Signal Transduction
- Abstract
The immunoglobulin G (IgG)-containing B lymphocyte antigen receptor (IgG-BCR) transmits a signal distinct from that of IgM-BCR or IgD-BCR, although all three use the same signal-transducing component, Igalpha/Igbeta. Here we demonstrate that the inhibitory coreceptor CD22 down-modulates signaling through IgM-BCR and IgD-BCR, but not that through IgG-BCR, because of the IgG cytoplasmic tail, which prevents CD22 phosphorylation. These results suggest that the cytoplasmic tail of IgG specifically enhances IgG-BCR signaling by preventing CD22-mediated signal inhibition. Enhanced signaling through IgG-BCR may be involved in efficient IgG production, which is crucial for immunity to pathogens.
- Published
- 2002
- Full Text
- View/download PDF
49. SHP-1 requires inhibitory co-receptors to down-modulate B cell antigen receptor-mediated phosphorylation of cellular substrates.
- Author
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Adachi T, Wienands J, Wakabayashi C, Yakura H, Reth M, and Tsubata T
- Subjects
- Down-Regulation, Humans, Intracellular Signaling Peptides and Proteins, Phosphorylation, Protein Tyrosine Phosphatase, Non-Receptor Type 6, Signal Transduction, Substrate Specificity, Tumor Cells, Cultured, B-Lymphocytes metabolism, Protein Tyrosine Phosphatases metabolism, Receptors, Antigen, B-Cell metabolism
- Abstract
Signaling through the B cell antigen receptor (BCR) is negatively regulated by the SH2 domain-containing protein-tyrosine phosphatase SHP-1, which requires association with tyrosine-phosphorylated proteins for activation. Upon BCR ligation, SHP-1 has been shown to associate with the BCR, the cytoplasmic protein-tyrosine kinases Lyn and Syk, and the inhibitory co-receptors CD22 and CD72. How SHP-1 is activated by BCR ligation and regulates BCR signaling is, however, not fully understood. Here we demonstrate that, in the BCR-expressing myeloma line J558L mu 3, CD72 expression reduces the BCR ligation-induced phosphorylation of the BCR component Ig alpha/Ig beta and its cytoplasmic effectors Syk and SLP-65. Substrate phosphorylation was restored by expression of dominant negative mutants of SHP-1, whereas the SHP-1 mutants failed to enhance phosphorylation of the cellular substrates in the absence of CD72. This indicates that SHP-1 is efficiently activated by CD72 but not by other pathways in J558L mu m3 cells and that inhibition of SHP-1 specifically activated by CD72 reverses CD72-induced dephosphorylation of cellular substrates in these cells. Taken together, BCR-induced SHP-1 activation is likely to require inhibitory co-receptors such as CD72, and SHP-1 appears to mediate the negative regulatory effect of CD72 on BCR signaling by dephosphorylating Ig alpha/Ig beta and its downstream signaling molecules Syk and SLP-65.
- Published
- 2001
- Full Text
- View/download PDF
50. CD72 negatively regulates signaling through the antigen receptor of B cells.
- Author
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Adachi T, Wakabayashi C, Nakayama T, Yakura H, and Tsubata T
- Subjects
- Animals, Antigens, CD genetics, Antigens, CD immunology, Antigens, CD metabolism, Antigens, Differentiation, B-Lymphocyte genetics, Antigens, Differentiation, B-Lymphocyte immunology, Antigens, Differentiation, B-Lymphocyte metabolism, Calcium metabolism, Calcium Signaling genetics, Calcium Signaling immunology, Down-Regulation genetics, Ligands, Lymphoma, B-Cell enzymology, Lymphoma, B-Cell genetics, Lymphoma, B-Cell immunology, Lymphoma, B-Cell metabolism, Mice, Mice, Inbred BALB C, Mice, Inbred DBA, Mitogen-Activated Protein Kinases metabolism, Receptors, Antigen, B-Cell immunology, Receptors, Antigen, B-Cell metabolism, Signal Transduction genetics, Spleen cytology, Spleen immunology, Spleen metabolism, Transfection, Tumor Cells, Cultured, Antigens, CD physiology, Antigens, Differentiation, B-Lymphocyte physiology, Down-Regulation immunology, Receptors, Antigen, B-Cell physiology, Signal Transduction immunology
- Abstract
The immunoreceptor tyrosine-based inhibition motif (ITIM) is found in various membrane molecules such as CD22 and the low-affinity Fc receptor for IgG in B cells and the killer cell-inhibitory receptor and Ly-49 in NK cells. Upon tyrosine phosphorylation at the ITIMs, these molecules recruit SH2 domain-containing phosphatases such as SH2-containing tyrosine phosphatase-1 and negatively regulate cell activity. The B cell surface molecule CD72 carries an ITIM and an ITIM-like sequence. We have previously shown that CD72 is phosphorylated and recruits SH2-containing tyrosine phosphatase-1 upon cross-linking of the Ag receptor of B cells (BCR). However, whether CD72 modulates BCR signaling has not yet been elucidated. In this paper we demonstrate that expression of CD72 down-modulates both extracellular signal-related kinase (ERK) activation and Ca2+ mobilization induced by BCR ligation in the mouse B lymphoma line K46micromlambda, whereas BCR-mediated ERK activation was not reduced by the ITIM-mutated form of CD72. Moreover, coligation with CD72 with BCR reduces BCR-mediated ERK activation in spleen B cells of normal mice. These results indicate that CD72 negatively regulates BCR signaling. CD72 may play a regulatory role in B cell activation, probably by setting a threshold for BCR signaling.
- Published
- 2000
- Full Text
- View/download PDF
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