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Dive into the research topics where Akihito Nagahara is active.

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Featured researches published by Akihito Nagahara.


Scandinavian Journal of Gastroenterology | 2001

Pooled Analysis on the Efficacy of the Second-line Treatment Regimens for Helicobacter pylori Infection

Mariko Hojo; Hiroto Miwa; Akihito Nagahara; Nobuhiro Sato

Background: Although many of the currently available Helicobacter pylori eradication regimens fail to cure 5%-12% of patients, an optimal re-treatment therapy for eradication-failure patients has still not been established. The aim of this study was to examine all reports concerning the efficacy of re-eradication regimens for H. pylori infection, and to establish optimal re-eradication regimens. Methods: Studies concerning re-eradication regimens were retrieved from the MEDLINE database, reference lists and major congress abstract lists up through December 1999. Data from all selected reports were pooled into several groups depending on second-line or initial therapies. Pooled eradication rates of re-treatment regimens were compared using Fishers exact test (P < 0.05). Results: Sixteen articles and 24 abstracts with 75 total treatment arms were included in this study. Pooled re-eradication rates by proton-pump inhibitor (PPI)-based dual therapy, PPI-based triple therapy, ranitidine bismuth-based triple therapy and quadruple therapy were 45.8%, 69.8%, 80.2% and 75.8%, respectively. Eradication rates from studies with two new antimicobials added were higher than rates from studies with only one new antimicrobial added (P = 0.0064). Conclusion: Ranitidine bismuth-based triple therapies, as well as quadruple therapies, seem to be the most effective re-treatment therapies in all currently undertaken therapies. The strategy of adding two new antimicrobials to previous regimens was also effective in re-eradication therapy.


Journal of Gastroenterology | 2005

Treatment of functional dyspepsia with antianxiety or antidepressive agents : systematic review

Mariko Hojo; Hiroto Miwa; Tetsuji Yokoyama; Toshifumi Ohkusa; Akihito Nagahara; Masato Kawabe; Daisuke Asaoka; Yuko Izumi; Nobuhiro Sato

BackgroundThe pathophysiology of functional dyspepsia (FD) has not been elucidated precisely; accordingly, effective management of FD has not yet been found. Until now, treatment with antianxiety or antidepressive agents has been empirically applied; however, the efficacy of these treatments has not been established. We carried out this study to estimate the efficacy of these treatment approaches by systematically reviewing the literature concerning trials with agents that are efficacious against anxiety, neurosis, or depression.MethodsArticles were searched from the MEDLINE database up to October 2003, using the terms, “antianxiety agents”, “antidepressants”, and “dyspepsia”, and from reference lists of published articles. Finally, studies in which the effectiveness of drugs was clearly stated were selected from the retrieved articles.ResultsThirteen articles, on 1717 patients, were selected from among 90 articles retrieved through our literature search. In 11 of the 13 studies, dyspeptic symptoms were improved significantly by treatment. Statistical analysis of 4 trials showed a significant benefit of treatment with antianxiety or antidepressive agents (pooled relative risk, 0.55; 95% confidence interval [CI], 0.36–0.85), although funnel plots were asymmetric.ConclusionsAntianxiety or antidepressive agents may be effective in the treatment of FD patients, though further clinical trials are necessary.


Alimentary Pharmacology & Therapeutics | 2004

Oesophageal hypersensitivity in Japanese patients with non‐erosive gastro‐oesophageal reflux diseases

Hiroto Miwa; Toshoku Minoo; Mariko Hojo; R. Yaginuma; Akihito Nagahara; Masato Kawabe; Akimitsu Ohkawa; Daisuke Asaoka; Akihiko Kurosawa; Toshifumi Ohkusa; Nobuhiro Sato

Background : Visceral hypersensitivity plays a major role in the pathogenesis of non‐erosive oesophageal reflux disease (NERD). Prevalence of NERD differs according to the population and geographical region. Oesophageal hypersensitivity in NERD has not been well studied, especially in Japanese patients.


Journal of Gastroenterology | 2007

Metabolic syndrome and gastrointestinal diseases

Sumio Watanabe; Mariko Hojo; Akihito Nagahara

Metabolic syndrome is a cluster of metabolic abnormalities consisting essentially of obesity, especially abdominal obesity. Metabolic syndrome has been highlighted as a risk factor for cardiovascular and other chronic diseases. Obesity has been implicated in various gastrointestinal diseases such as gastroesophageal reflux diseases and colorectal cancer. Recently, abdominal obesity has been shown to be more important than obesity as expressed by an elevated body mass index as a causative factor for the development of these diseases. In addition to the mechanical effects of obesity, such as an increase in intra-abdominal pressure from large amounts of adipose tissue, substances that adipose tissues secrete, such as tumor necrosis factor-α, interleukin-6, leptin, and insulin-like growth factor-1, have been proposed to be pathogenic links to these diseases. In this review, we discuss the association of metabolic syndrome or the individual components of metabolic syndrome, focusing on obesity and abdominal obesity, with gastrointestinal diseases.


Alimentary Pharmacology & Therapeutics | 1999

Impact of rabeprazole, a new proton pump inhibitor, in triple therapy for Helicobacter pylori infection—comparison with omeprazole and lansoprazole

Hiroto Miwa; Ryuichi Ohkura; Toshio Murai; Kenji Sato; Akihito Nagahara; Shu Hirai; Sumio Watanabe; Nobuhiro Sato

: A recent trend in curative therapy for Helicobacter pylori infection is the so‐called triple therapy, which consists of a proton pump inhibitor (PPI) and two different antimicrobials. Various regimens employing this triple therapy have been reported. However, little is known about the effectiveness of rabeprazole, a recently developed proton pump inhibitor, when used in the triple therapy.


The American Journal of Gastroenterology | 2009

Efficacy of the 5-HT1A Agonist Tandospirone Citrate in Improving Symptoms of Patients With Functional Dyspepsia: A Randomized Controlled Trial

Hiroto Miwa; Akihito Nagahara; Kazunari Tominaga; Tetsuji Yokoyama; Y Sawada; Kazuhiko Inoue; Kiyoshi Ashida; Takumi Fukuchi; Mariko Hojo; Hiroharu Yamashita; Toshihiko Tomita; Kazutoshi Hori; Tsutomu Oshima

OBJECTIVES:Functional dyspepsia (FD) is a common condition in the general population; however, its treatment remains a challenge. The aim of this study was to examine the efficacy of tandospirone citrate, a new partial agonist of the 5-hydroxytryptamine 1A (5-HT1A) receptor, in improving the symptoms of patients with FD.METHODS:In this double-blind, placebo-controlled, multicenter study, FD patients were randomized to treatment with 10 mg t.i.d. tandospirone citrate or to placebo for 4 weeks. The primary end point was change in abdominal symptom scores. The difference in the proportion of responders (a total abdominal symptom score of 0 or 1) was also assessed. The quality-of-life questionnaire, the SF-8, and a psychological test questionnaire, the State-Trait Anxiety Inventory (STAI), were completed at baseline and at weekly intervals.RESULTS:Data were available for 144 patients: 73 for tandospirone and 71 for placebo. Improvements in total abdominal scores were significantly larger with tandospirone than placebo at weeks 1, 2, and 4. Significantly greater improvements in the tandospirone group were observed in upper abdominal pain (P=0.02) and discomfort (P=0.002) at week 4. The proportion of responders was significantly greater in the active treatment arm at weeks 3 (P=0.017) and 4 (P=0.0016). Significant improvements in STAI (P<0.0001) were reported in both arms, as well as in the majority of questions in the SF-8 (P=0.04). No serious adverse events were reported, with similar rates in both study arms.CONCLUSIONS:Despite a considerable placebo effect, the benefits of tandospirone were shown in terms of improvement in abdominal symptom scores.


Gastrointestinal Endoscopy | 2009

Endoscopic submucosal dissection of large colorectal tumors by using a novel spring-action S-O clip for traction (with video)

Naoto Sakamoto; Taro Osada; Tomoyoshi Shibuya; Kazuko Beppu; Kenshi Matsumoto; Hiroki Mori; Masato Kawabe; Akihito Nagahara; Michiro Otaka; Tatsuo Ogihara; Sumio Watanabe

BACKGROUND Endoscopic submucosal dissection (ESD) allows en bloc resection of large GI neoplasms, regardless of their size; however, technical difficulties associated with ESD in the colorectum make it less widely applied in the treatment of tumors in this region. To address this difficulty, we designed a rubber strip-based traction device, called the S-O clip (Sakamoto-Osada clip) and reported previously that ESD with this device was effective for complete resection of large, superficial colorectal neoplasms. In this report, we describe a novel spring-action version of the S-O clip (spring S-O clip) that improves the facility of clip use during ESD of colorectal tumors. OBJECTIVE To evaluate the efficacy and safety of the spring S-O clip for ESD of colorectal neoplasms. DESIGN Case series. SETTING Juntendo University Hospital. MAIN OUTCOME MEASUREMENTS The efficacy and safety of the spring S-O clip traction device during ESD of colorectal tumors. RESULTS In 3 cases, a large, superficial neoplasm in the right side of the colon was removed safely and successfully en bloc without complication. Procedure times for the 3 cases were 44, 27, and 49 minutes, with resected specimens measuring 40, 24, and 35 mm, respectively. LIMITATION Uncontrolled study. CONCLUSION This limited case series demonstrates that spring S-O clip-assisted ESD is safe and effective for en bloc resection of large superficial neoplasms in the right side of the colon.


Alimentary Pharmacology & Therapeutics | 2007

Efficacy of rabeprazole on heartburn symptom resolution in patients with non‐erosive and erosive gastro‐oesophageal reflux disease: a multicenter study from Japan

Hiroto Miwa; Makoto Sasaki; Takahisa Furuta; Tomoyuki Koike; Yasuki Habu; Masanori Ito; Yasuhiro Fujiwara; Tsuneya Wada; Akihito Nagahara; Michio Hongo; Tsutomu Chiba; Yoshikazu Kinoshita

Background  Few studies have compared the efficacy of proton pump inhibitors in resolving the symptoms of non‐erosive reflux disease (NERD) and of erosive gastro‐oesophageal reflux disease (GERD) in Japan.


Journal of Gastroenterology | 2015

Evidence-based clinical practice guidelines for functional dyspepsia

Miwa H; Motoyasu Kusano; Tomiyasu Arisawa; Tadayuki Oshima; Mototsugu Kato; Takashi Joh; Hidekazu Suzuki; Kazunari Tominaga; Koji Nakada; Akihito Nagahara; Seiji Futagami; Noriaki Manabe; Akio Inui; Ken Haruma; Kazuhide Higuchi; Koji Yakabi; Michio Hongo; Naomi Uemura; Yoshikazu Kinoshita; Kentaro Sugano; Tooru Shimosegawa

General interest in functional gastrointestinal disorders is increasing among Japanese doctors as well as patients. This increase can be attributed to a number of factors, including recent increased interest in quality of life and advances in our understanding of the pathophysiology of gastrointestinal disease. Japan recently became the world’s first country to list “functional dyspepsia” as a disease name for national insurance billing purposes. However, recognition and understanding of functional dyspepsia (FD) remain poor, and no standard treatment strategy has yet been established. Accordingly, the Japanese Society of Gastroenterology (JSGE) developed an evidence-based clinical practice guideline for FD, consisting of five sections: concept, definition, and epidemiology; pathophysiology; diagnosis; treatment; and prognosis and complications. This article summarizes the Japanese guideline, with particular focus on the treatment section. Once a patient is diagnosed with FD, the doctor should carefully explain the pathophysiology and benign nature of this condition, establish a good doctor–patient relationship, and then provide advice for daily living (diet and lifestyle modifications, explanations, and reassurance). The proposed pharmacological treatment is divided into two steps: initial treatment including an acid inhibitory drug (H2RA or PPI) or prokinetics, (strong recommendation); second-line treatment including anxiolytics, antidepressants, and Japanese traditional medicine (weak recommendation). H. pylori eradication, strongly recommended with a high evidence level, is positioned separately from other treatment flows. Conditions that do not respond to these treatment regimens are regarded as refractory FD. Patients will be further examined for other organic disorders or will be referred to specialists using other approaches such as psychosomatic treatment.


Helicobacter | 2000

Addition of Metronidazole to Rabeprazole-Amoxicillin-Clarithromycin Regimen for Helicobacter pylori Infection Provides an Excellent Cure Rate with Five-Day Therapy

Akihito Nagahara; Hiroto Miwa; Kaoru Ogawa; Akihiko Kurosawa; Ryuichi Ohkura; Noboru Iida; Nobuhiro Sato

Background. New triple therapy for eradication of Helicobacter pylori based on a proton pump inhibitor (PPI) provides a cure rate of approximately 90% with few adverse effects. Recently, a PPI‐based quadruple therapy, which consists of a PPI plus bismuth‐based triple therapy for 7 days, has been studied, and a sufficient eradication rate has been achieved. However, a shorter duration results in improved compliance. In this study, newly developed short‐term, simple twice‐daily quadruple therapy consisting of rabeprazole, amoxicillin, clarithromycin, and metronidazole (RACM) was compared with a PPI‐based triple‐therapy regimen for eradication of H. pylori.

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Hiroto Miwa

Hyogo College of Medicine

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