Toshihiro Koyama

Dr. Toshihiro Koyama

orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 November 2019 in JAMA Oncology
Verified
Journal Article
Open access
PDF file
YZYoshito Zamami
Yoshito Zamami
TNTakahiro Niimura
Takahiro Niimura
NONaoto Okada
Naoto Okada
TKToshihiro Koyama
Toshihiro Koyama
KFKeijo Fukushima
Keijo Fukushima
KIKeisuke Ishizawa
Keisuke Ishizawa
Immune-related adverse events (irAE) can develop in patients treated with immune checkpoint inhibitors (ICIs). For example, ICI treatment can increase the risk of myocarditis as a lethal irAE,1 with a mortality rate up to 50%.2 However, the frequency of ICI-related myocarditis is low, and thus the detailed pathogenic mechanisms and risk factors remain unknown. General myocarditis and ICI-related myocarditis have distinct manifestations, suggesting different risk factors; however, the differences of risk factors in these 2 types are unclear.

1 January 2008 in Biological and Pharmaceutical Bulletin
Verified
Journal Article
Closed access
PDF file
YZYoshito Zamami
Yoshito Zamami
STShingo Takatori
Shingo Takatori
MGMitsuhiro Goda
Mitsuhiro Goda
TKToshihiro Koyama
Toshihiro Koyama
YIYukiko Iwatani
Yukiko Iwatani
HKHiromu Kawasaki
Hiromu Kawasaki
Royal jelly (RJ) is known to contain excellent nutrition and a variety of biological activities. The present study was designed to investigate the effects of RJ on insulin resistance (hyperinsulinemia) in fructose-drinking rats (FDR; insulin resistance animal model). Male Wistar rats (6 weeks old) received 15% fructose solution in drinking water for 8 weeks. FDR showed significant increases in plasma levels of insulin and triglyceride, Homeostasis Model Assessment ratio (HOMA-R, an index of insulin resistance), and systolic blood pressure, but not blood glucose levels, when compared with control rats. RJ (100, 300 mg/kg, p.o.) treatment for 8 weeks significantly decreased the plasma levels of insulin and triglyceride, HOMA-R, without affecting blood glucose or total cholesterol levels and tended to lower systolic blood pressure. In isolated and perfused mesenteric vascular beds of FDR, RJ treatment resulted in a significant reduction in sympathetic nerve-mediated vasoconstrictor response to periarterial nerve stimulation (PNS) and tended to increase the calcitonin gene-related peptide (CGRP) nerve-mediated vasodilator response to PNS, compared with those in untreated FDR. However, RJ treatment did not significantly affect norepinephrine-induced vasoconstriction or CGRP-induced vasodilation. These results suggest that RJ could be an effective functional food to prevent insulin resistance associated with the development of hypertension.

8 July 2016 in BMC Public Health
Verified
Journal Article
Open access
PDF file
YHYuji Higuchi
Yuji Higuchi
MIMasatoshi Inagaki
Masatoshi Inagaki
TKToshihiro Koyama
Toshihiro Koyama
YKYoshihisa KITAMURA
Yoshihisa KITAMURA
TSToshiaki Sendo
Toshiaki Sendo
NYNorihito Yamada
Norihito Yamada
Opportunities for face-to-face communication with patients is increasing in modern hospital pharmacist practice. This may impose new burdens on hospital pharmacists. We performed a cross-sectional study to examine the prevalence of psychological distress, burnout, and compassion fatigue among hospital pharmacists. We also investigated possible relevant factors, such as sex, years of experience, hospital size, interpersonal work hours, and personality traits related to communication. We mailed self-administered questionnaires to all pharmacists (n = 823) belonging to the prefectural society of hospital pharmacists in Japan. The questionnaires were the General Health Questionnaire (GHQ-12), Burnout (BO) and Compassion Fatigue and Secondary Traumatic Stress (CF/STS) subscales of the Professional Quality of Life Scale, the Autism Spectrum Quotient (AQ), and the Adult ADHD (attention deficit hyperactivity disorder) Self-Report Scale (ASRS). We examined associations between personality traits (AQ, ASRS) and psychological burden (GHQ-12, BO, CF/STS) using rank ANCOVA or multivariate logistic regression analyses. Complete responses were obtained from 380 pharmacists (46.2 % response rate). A substantial number of participants obtained scores that were higher than the cutoff points of the GHQ-12 (54.7 %), BO (49.2 %), and CF/STS (29.2 %). The GHQ-12 scores were negatively affected by years of experience (p < 0.001), and positively affected by AQ (p < 0.001) and ASRS (p < 0.001) scores. The BO scores was positively affected by AQ (p < 0.001) and ASRS (p = 0.001) scores, while the CF/STS (p = 0.023) score was negatively affected by years of experience, and positively affected by AQ (p < 0.001) and ASRS (p < 0.001) scores. There is a high prevalence of psychological distress and work-related burnout/CF among hospital pharmacists. Additionally, two common personality traits, such as autistic-like traits and ADHD-like symptoms, which might be related to communication style, could increase the risk of psychological distress and burnout/CF. Early risk assessment and preventive interventions that are specialized for these characteristics could protect individuals with these specific traits from burnout.

6 October 2018 in Journal of the American Geriatrics Society
Verified
Journal Article
Closed access
PDF file
HOHiroshi Onoue
Hiroshi Onoue
TKToshihiro Koyama
Toshihiro Koyama
YZYoshito Zamami
Yoshito Zamami
HHHideharu Hagiya
Hideharu Hagiya
YTYasuhisa Tatebe
Yasuhisa Tatebe
MKMitsunobu R. Kano
Mitsunobu R. Kano

9 November 2018 in Epidemiology and Infection
Verified
Journal Article
Open access
PDF file
HHH. Hagiya
H. Hagiya
TKToshihiro Koyama
Toshihiro Koyama
YZY. Zamami
Y. Zamami
YMY. Minato
Y. Minato
YTY. Tatebe
Y. Tatebe
MKMitsunobu R. Kano
Mitsunobu R. Kano
Japan is still a medium-burden tuberculosis (TB) country. We aimed to examine trends in newly notified active TB incidence and TB-related mortality in the last two decades in Japan. This is a population-based study using Japanese Vital Statistics and Japan Tuberculosis Surveillance from 1997 to 2016. We determined active TB incidence and mortality rates (per 100 000 population) by sex, age and disease categories. Joinpoint regression was applied to calculate the annual percentage change (APC) in age-adjusted mortality rates and to identify the years showing significant trend changes. Crude and age-adjusted incidence rates reduced from 33.9 to 13.9 and 37.3 to 11.3 per 100 000 population, respectively. Also, crude and age-adjusted mortality rates reduced from 2.2 to 1.5 and 2.8 to 1.0 per 100 000 population, respectively. Average APC in the incidence and mortality rates showed significant decline both in men (−6.2% and −5.4%, respectively) and women (−5.7% and −4.6%, respectively). Age-specific analysis demonstrated decreases in incidence and mortality rates for every age category, except for the incidence trend in the younger population. Although trends in active TB incidence and mortality rates in Japan have favourably decreased, the rate of decline is far from achieving TB elimination by 2035.

9 December 2005 in European Journal of Pharmacology
Verified
Journal Article
Closed access
HJHonghua Jin
Honghua Jin
TKToshihiro Koyama
Toshihiro Koyama
YHYukako Hatanaka
Yukako Hatanaka
SAShinji Akiyama
Shinji Akiyama
FTFusako Takayama
Fusako Takayama
HKHiromu Kawasaki
Hiromu Kawasaki