Akihito Nagahara

ORCID: 0000-0001-5979-4384
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About
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Research Areas
  • Helicobacter pylori-related gastroenterology studies
  • Gastric Cancer Management and Outcomes
  • Gastroesophageal reflux and treatments
  • Eosinophilic Esophagitis
  • Gastrointestinal Tumor Research and Treatment
  • Metastasis and carcinoma case studies
  • Gastrointestinal motility and disorders
  • Gastrointestinal disorders and treatments
  • Gut microbiota and health
  • Esophageal and GI Pathology
  • Microscopic Colitis
  • Clostridium difficile and Clostridium perfringens research
  • Colorectal Cancer Screening and Detection
  • Esophageal Cancer Research and Treatment
  • Inflammatory Bowel Disease
  • Gastrointestinal Bleeding Diagnosis and Treatment
  • Genetic factors in colorectal cancer
  • Mycobacterium research and diagnosis
  • Pancreatic and Hepatic Oncology Research
  • Liver Disease Diagnosis and Treatment
  • Pathogenesis and Treatment of Hiccups
  • Colorectal Cancer Treatments and Studies
  • Neuroendocrine Tumor Research Advances
  • Inflammatory mediators and NSAID effects
  • Veterinary medicine and infectious diseases

Juntendo University
2016-2025

The Japanese Society of Gastroenterological Surgery
2015-2024

Juntendo University Hospital
2002-2022

Juntendo University Shizuoka Hospital
2015-2021

Shonan Kamakura General Hospital
2016

Creative Research Enterprises (United States)
2016

Hiroshima University Hospital
2009

University Gastroenterology
2008

Dokkyo Medical University Saitama Medical Center
2002-2004

Fecal microbiota transplantation following triple-antibiotic therapy (amoxicillin/fosfomycin/metronidazole) improves dysbiosis caused by reduced Bacteroidetes diversity in patients with ulcerative colitis (UC). We investigated the correlation between species abundance and UC activity. samples from 34 healthy controls 52 active (Lichtiger’s clinical activity index ≥5 or Mayo endoscopic subscore ≥1) were subjected to next-generation sequencing HSP60 as a target bacterial metagenome analysis. A...

10.3390/jcm10081749 article EN Journal of Clinical Medicine 2021-04-17

Background: Probiotics have been reported to ameliorate cognitive impairment. Objective: We investigated the effect of probiotic strain Bifidobacterium breve MCC1274 (A1) in enhancing cognition and preventing brain atrophy older patients with mild impairment (MCI). Methods: In this RCT, 130 aged from 65 88 years old suspected MCI received once daily either (B. MCC1274, 2×1010 CFU) or placebo for 24 weeks. Cognitive functions were assessed by ADAS-Jcog MMSE tests. Participants underwent MRI...

10.3233/jad-220148 article EN other-oa Journal of Alzheimer s Disease 2022-05-10

Functional dyspepsia (FD) is a common condition in the general population; however, its treatment remains challenge. The aim of this study was to examine efficacy tandospirone citrate, new partial agonist 5-hydroxytryptamine 1A (5-HT1A) receptor, improving symptoms patients with FD.In double-blind, placebo-controlled, multicenter study, FD were randomized 10 mg t.i.d. citrate or placebo for 4 weeks. primary end point change abdominal symptom scores. difference proportion responders (a total...

10.1038/ajg.2009.427 article EN The American Journal of Gastroenterology 2009-07-28

Abstract Background and Aim Magnifying endoscopy with narrow‐band imaging (ME‐NBI) has made a huge contribution to clinical practice. However, acquiring skill at ME‐NBI diagnosis of early gastric cancer (EGC) requires considerable expertise experience. Recently, artificial intelligence (AI), using deep learning convolutional neural network (CNN), remarkable progress in various medical fields. Here, we constructed an AI‐assisted CNN computer‐aided (CAD) system, based on images, diagnose EGC...

10.1111/jgh.15190 article EN cc-by-nc Journal of Gastroenterology and Hepatology 2020-07-18

Gastric adenocarcinoma of the fundic gland (chief cell predominant type, GA-FG-CCP) was recently proposed as a new, rare variant gastric adenocarcinoma. The aim current study to evaluate endoscopic features GA-FG-CCP. A total 10 GA-FG-CCPs were included and evaluated retrospectively. clinicopathological lesions analyzed provide information diagnostic value. classified into two categories: submucosal tumor shape (60 %) flat or depressed type (40 %). Endoscopically, most common %), whitish...

10.1055/s-0033-1359042 article EN Endoscopy 2013-12-11

Recently, problems associated with proton pump inhibitor (PPI) use have begun to surface. PPIs influence the gut microbiota; therefore, PPI may increase risk of enteric infections and cause bacterial translocation. In this study, we investigated fecal microbiota composition, organic acid concentrations pH, bacteria in blood same patients before after use. Twenty reflux esophagitis based on endoscopic examination received 8 weeks treatment PPIs. To analyze composition concentrations, 16S 23S...

10.1007/s10620-018-5122-4 article EN cc-by-nc Digestive Diseases and Sciences 2018-05-24

Immunoglobulin A (IgA) is essential for defense of the intestinal mucosa against harmful pathogens. Gut microbiota impact IgA production, but specific species responsible production remain largely elusive. Previous studies have shown that and Bacteroidetes , major phyla gut microbiota, were increased in soluble high-fiber diet-fed mice. We show here levels expression activation-induced cytidine deaminase (AID) large intestine lamina propria, which crucial class switch recombination from IgM...

10.1128/aem.00405-20 article EN Applied and Environmental Microbiology 2020-04-21

Abstract Background Functional dyspepsia ( FD ), a heterogeneous disorder, involves multiple pathogenetic mechanisms. Developing treatments for has been challenging. We performed randomized, placebo‐controlled, double‐blind clinical trial to determine the efficacy of rikkunshito, Japanese herbal medicine, in patients. Methods patients (n = 192) who met Rome III criteria without Helicobacter pylori infection, predominant heartburn, and depression were enrolled at 56 hospitals Japan. After 2...

10.1111/nmo.13319 article EN Neurogastroenterology & Motility 2018-03-02

The proportion of certain Bacteroidota species decreased in patients with ulcerative colitis, and the recovery is associated efficacy fecal microbiota transplantation therapy. We hypothesized that may advance colitis treatment. Accordingly, we aimed to evaluate anti-inflammatory effects strains isolated from donors.

10.1093/ibd/izae080 article EN Inflammatory Bowel Diseases 2024-05-11

Although many of the currently available Helicobacter pylori eradication regimens fail to cure 5%-12% patients, an optimal re-treatment therapy for eradication-failure patients has still not been established. The aim this study was examine all reports concerning efficacy re-eradication H. infection, and establish regimens.Studies were retrieved from MEDLINE database, reference lists major congress abstract up through December 1999. Data selected pooled into several groups depending on...

10.1080/003655201300191941 article EN Scandinavian Journal of Gastroenterology 2001-07-01

Abstract Background and Aim: Colonoscopy plays an integral role in the diagnosis, management surveillance of ulcerative colitis (UC). In present study we assessed relationship between endoscopic histological findings, clinical symptoms, laboratory data. Methods: We performed total colonoscopy examinations 54 consecutive patients with UC. Seven segments (appendiceal region, cecum, ascending colon, transverse descending sigmoid rectum) were scored for activity. The also evaluated using a...

10.1111/j.1440-1746.2008.05413.x article EN Journal of Gastroenterology and Hepatology 2008-12-01

This study evaluated inter- and intraobserver agreement in the assessment of ulcerative colitis (UC) activity using 4 established indices a newly designed Modified 6-point Activity Index. In all, 279 endoscopic pictures inflammatory lesions from 93 UC patients were displayed twice to expert trainee endoscopists, at an interval 1 month. Each picture was assessed for changes (Matts, Schroeder [a.k.a. Mayo Score], Baron, Blackstone) our new Weighted kappa statistics used estimate intra-...

10.1002/ibd.21000 article EN Inflammatory Bowel Diseases 2009-07-02

Background The efficacy of proton pump inhibitors (PPIs) for treating functional dyspepsia (FD) is not well established. Aim This study, named the SAMURAI aimed to assess and dose–response relationship rabeprazole in Japanese patients with FD a multicentre, double-blinded, randomised, placebo-controlled trial. Methods Investigated was diagnosed using Rome III criteria. Subjects who did respond 1 week single-blind placebo treatment run-in period were randomly assigned 8 weeks double-blind 10...

10.1111/apt.12444 article EN Alimentary Pharmacology & Therapeutics 2013-08-20

We previously demonstrated that fresh fecal microbiota transplantation (FMT) following triple antibiotic therapy (amoxicillin, fosfomycin, metronidazole (AFM); A-FMT) resulted in effective colonization of Bacteroidetes species, leading to short-term clinical response ulcerative colitis (UC). Its long-term efficacy and criteria for donor selection are unknown. Here, we analyzed the A-FMT compared AFM monotherapy (mono-AFM). was administered patients with mild severe UC 2 weeks until days...

10.3390/jcm9061650 article EN Journal of Clinical Medicine 2020-05-31
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