Osamu Nomura

Dr. Osamu Nomura


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

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

Representative Publications

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12 August 2016 in Journal of Medical Case Reports
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NYNoboru Yatagai
Noboru Yatagai
HUHiroya Ueyama
Hiroya Ueyama
TSTomoyoshi Shibuya
Tomoyoshi Shibuya
KHKeiichi Haga
Keiichi Haga
MTMasahito Takahashi
Masahito Takahashi
SWSumio Watanabe
Sumio Watanabe
Small intestinal lipomas are rare, usually asymptomatic, and most commonly encountered incidentally during investigation of the gastrointestinal tract for another reason. However, they may cause obscure gastrointestinal bleeding. We report a case of obscure gastrointestinal bleeding due to a small intestinal lipoma. A 69-year-old Japanese man on antiplatelet therapy presented to our department with tarry stools and anemic symptoms. A small intestinal tumor was detected by capsule endoscopy and double-balloon endoscopy. After laparoscopic resection, the tumor was confirmed to be a lipoma. Small intestinal lipomas are difficult to detect by conventional modalities, but capsule endoscopy and double-balloon endoscopy are good modalities for the diagnosis of small intestinal lipomas. Treatment of small intestinal lipomas should be selected carefully, considering the tumor size, size of stalk, administration of antithrombotic therapy, and endoscopic operability.

Verified
Journal Article
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KHKeiichi Haga
Keiichi Haga
TSTomoyoshi Shibuya
Tomoyoshi Shibuya
KNKei Nomura
Kei Nomura
KOKoki Okahara
Koki Okahara
ONOsamu Nomura
Osamu Nomura
ANAkihito Nagahara
Akihito Nagahara
Background: Tacrolimus (TAC) is used for the management of ulcerative colitis (UC). However, there are few reports on the effectiveness of its long-term administration. TAC is also known to cause renal toxicity. The aim of this study was to evaluate long-term effectiveness and monitor changes in renal function during prolonged TAC use in patients with UC. Methods: Medical records of 50 UC patients treated with TAC were retrospectively reviewed. Clinical outcomes were assessed at 6, 12, 24, and 36 months after initiating TAC. We also monitored chronological changes in renal function. Results: Thirty-nine patients were treated with TAC for more than 3 months. Relapse-free survival among these patients at 6, 12, 24, and 36 months was 82%, 69%, 41%, and 23%, respectively. On the other hand, renal function was reduced in 35.9% of patients. We found that irreversible renal dysfunction was more likely to occur in cases in which the estimated glomerular-filtration rate (eGFR) was reduced by more than 30%. Conclusion: This study demonstrated the potential use of TAC as an effective option in the long-term medical management of UC, although it tended to increase the risk of nephrotoxicity. There is a need for the careful monitoring of renal function during TAC administration.

9 October 2022 in Biomedicines
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Journal Article
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KHKeiichi Haga
Keiichi Haga
TSTomoyoshi Shibuya
Tomoyoshi Shibuya
TOTaro Osada
Taro Osada
SSShunsuke Sato
Shunsuke Sato
YFYuka Fukuo
Yuka Fukuo
ANAkihito Nagahara
Akihito Nagahara
Vedolizumab (VDZ) is an α4β7 integrin-antibody used to manage refractory ulcerative colitis (UC). This retrospective multicenter study aimed to identify predictors of efficacy or the time points when evaluation of VDZ therapy for UC would be most useful. We compiled data on 87 patients with moderate to severe active UC that was treated with VDZ. Overall clinical remission (CR) rates at 6 weeks and 52 weeks after VDZ administration were 44.4% (bio-naïve 44.2%, bio-failure 44.8%) and 52.8% (bio-naïve 53.5%, bio-failure 51.7%) respectively. Also, 83.3% (bio-naïve 81.3%, bio-failure 85.7%) of patients achieved mucosal healing at week 52. Among patients with a CR at week 52, 73.3% had a CR at week 6. In contrast, of patients who discontinued VDZ, 82.4% had not reached a CR at week 6. Our study demonstrated that VDZ was effective in a large percentage of UC patients, with a high mucosal healing rate even after prior biological exposures. This suggests that VDZ can be a treatment option even in bio-failure cases. Additionally, it was considered that early CR can predict long-term remission and that week 6 can be a helpful evaluation point for treatment decisions when using VDZ for UC.

21 May 2025 in Nutrients
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DADaisuke Asaoka
Daisuke Asaoka
KTKazuya Toda
Kazuya Toda
SYShin Yoshimoto
Shin Yoshimoto
NKNoriko Katsumata
Noriko Katsumata
TOToshitaka Odamaki
Toshitaka Odamaki
NSNobuhiro Sato
Nobuhiro Sato
Background/Objectives: Sarcopenia (SA), an age-related impairment in skeletal muscle mass and function, is related to gut microbiota (GM) through inflammation and short-chain fatty acid (SCFA) generation. However, data on this relationship in older Japanese adults remain limited. We investigated the relationship of GM composition with SA, based on the Asian Working Group for Sarcopenia (AWGS) 2019 criteria, among elderly Japanese outpatients. Methods: Between June 2022 and January 2023, this prospective cross-sectional study enrolled 356 community-dwelling outpatients aged ≥ 65 years at the Department of Gastroenterology, Juntendo Tokyo Koto Geriatric Medical Center. SA was determined based on the AWGS 2019 consensus criteria. GM was analyzed using 16S rRNA gene sequencing, and alpha/beta diversity, taxonomic composition, detection rates, and correlations with skeletal muscle mass index (SMI), grip strength, and gait speed were investigated. Results: Among 356 (144 males, 212 females) participants, 50 (35 males, 15 females) had SA. Differences in GM diversity and composition were primarily noted among male participants. Men with SA had lower alpha diversity and distinct beta diversity profiles. Six bacterial genera—Eubacterium I, Fusicatenibacter, Holdemanella, Unclassified Lachnospira, Enterococcus H, and Bariatricus—had lower abundances in the SA group. Several of these genera showed positive correlations with SMI, grip strength, and gait speed. Conversely, no differences in GM characteristics were seen among females. Conclusions: GM composition was associated with SA among older Japanese men. These sex-specific differences emerged consistently, highlighting the potential of microbiota-based strategies for SA prevention in older males.

17 May 2024 in Biomedicines
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MOMasashi Omori
Masashi Omori
TSTomoyoshi Shibuya
Tomoyoshi Shibuya
HIHirotaka Ishino
Hirotaka Ishino
YFYuka Fukuo
Yuka Fukuo
RORina Odakura
Rina Odakura
ANAkihito Nagahara
Akihito Nagahara
Ustekinumab (UST) is an anti–IL-12/23p40 monoclonal antibody used to treat inflammatory bowel disease. The aim of this retrospective, multicenter study was to investigate the effectiveness of UST administration in achieving remission in patients with ulcerative colitis (UC) and to determine patient characteristics that influence its effectiveness. Of 88 UC patients who received UST from March 2020 to August 2023, 47 with traceable data and for whom 56 weeks had elapsed since the start of treatment received UST to induce remission. The remission rates at 8 weeks were 66% overall, 73.7% for Bio Naïve (never used biologics/JAK inhibitors), and 60.7% for Bio Failure (used biologics/JAK inhibitors) groups. Remission rates at 56 weeks were 70.2% overall, 73.7% for Bio Naïve, and 67.9% for Bio Failure groups. Ustekinumab showed good mid-to-long-term results in the induction of remission of UC in both Bio Naïve and Bio Failure groups. The group showing remission at 8 weeks had a significantly higher non-relapse or continuation rate (proportion of patients with no worsened symptoms necessitating surgery/drug change) at 56 weeks. Predictive factors for achieving remission after UST in UC were female gender, low body mass index, and low lymphocyte-to-monocyte ratio. Thus, UST is effective for moderate-to-severe UC.

Verified
Journal Article
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KTKo Tomishima
Ko Tomishima
SIShigeto Ishii
Shigeto Ishii
TFToshio Fujisawa
Toshio Fujisawa
MIMuneo Ikemura
Muneo Ikemura
MUMako Ushio
Mako Ushio
Hiroyuki IsayamaHiroyuki Isayama
Hiroyuki Isayama
Background and aims: The goals of the management of benign biliary stricture (BBS) are to relieve symptoms and resolve short-/long-term stricture. We performed fully covered self-expandable metallic stent (hereafter, FCSEMS) placement for BBS using various methods and investigated the treatment outcomes and adverse events (AEs). Methods: We retrospectively studied patients who underwent FCSEMS placement for refractory BBS through various approaches between January 2017 and February 2020. FCSEMS were placed for 6 months, and an additional FCSEMS was placed if the stricture had not improved. Technical success rate, stricture resolution rate, and AE were measured. Results: A total of 26 patients with BBSs that were difficult to manage with plastic stents were included. The mean overall follow-up period was 43.3 ± 30.7 months. The cause of stricture was postoperative (46%), inflammatory (31%), and chronic pancreatitis (23%). There were four insertion methods: endoscopic with duodenoscopy, with enteroscopy, EUS-guided transmural, and percutaneous transhepatic. The technical success rate was 100%, without any AE. Stricture resolution was obtained in 19 (83%) of 23 cases, except for three cases of death due to other causes. Stent migration and cholangitis occurred in 23% and 6.3%, respectively. Stent fracture occurred in two cases in which FCSEMSs were placed for more than 6 months (7.2 and 10.3 months). Conclusion: FCSEMS placement for refractory BBS via various insertion routes was feasible and effective. FCSEMSs should be exchanged every 6 months until stricture resolution because of stent durability. Further prospective study for confirmation is required, particularly regarding EUS-guided FCSEMS placement.