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Dive into the research topics where Hiroyuki Komori is active.

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Featured researches published by Hiroyuki Komori.


Gastroenterology Research and Practice | 2016

Procedure Time for Gastric Endoscopic Submucosal Dissection according to Location, considering Both Mucosal Circumferential Incision and Submucosal Dissection

Hironori Konuma; Kenshi Matsumoto; Hiroya Ueyama; Hiroyuki Komori; Yoichi Akazawa; Misuzu Ueyama; Yuta Nakagawa; Takashi Morimoto; Tsutomu Takeda; Kohei Matsumoto; Daisuke Asaoka; Mariko Hojo; Akihito Nagahara; Takashi Yao; Akihisa Miyazaki; Sumio Watanabe

Background. Previous assessments of technical difficulty and procedure time for endoscopic submucosal dissection (ESD) of gastric neoplasms did not take into account several critical determinants of these parameters. However, two key phases of ESD determine the total procedure time: the mucosal circumference incision speed (CIS) and submucosal dissection speed (SDS). Methods. We included 302 cases of en bloc and R0 resection of gastric neoplasms performed by 10 operators who had completed the training program at our hospital. Twelve locations were classified based on multiple criteria, such as condition of surrounding mucosa, lesion vascularity, presence of submucosal fat, ulcers, scars, fibrosis, and scope and device maneuverability. Lesions in different locations were classified into three groups based on the length of the procedure: fast, moderate, or late. Results. A significant difference was found in CIS and SDS for each location (p < 0.01), which demonstrates the validity of this classification system. In several locations, CIS and SDS were not consistent with each other. Conclusion. CIS and SDS did not correspond to each other even for lesions in the same location. Consideration of ESD procedure time for gastric neoplasms requires a more elaborate classification system than that previously reported.


World Journal of Gastroenterology | 2016

Clinicopathological features of alpha-fetoprotein producing early gastric cancer with enteroblastic differentiation

Kohei Matsumoto; Hiroya Ueyama; Kenshi Matsumoto; Yoichi Akazawa; Hiroyuki Komori; Tsutomu Takeda; Takashi Murakami; Daisuke Asaoka; Mariko Hojo; Natsumi Tomita; Akihito Nagahara; Yoshiaki Kajiyama; Takashi Yao; Sumio Watanabe

AIM To investigate clinicopathological features of early stage gastric cancer with enteroblastic differentiation (GCED). METHODS We retrospectively investigated data on 6 cases of early stage GCED and 186 cases of early stage conventional gastric cancer (CGC: well or moderately differentiated adenocarcinoma) who underwent endoscopic submucosal dissection or endoscopic mucosal resection from September 2011 to February 2015 in our hospital. GCED was defined as a tumor having a primitive intestine-like structure composed of cuboidal or columnar cells with clear cytoplasm and immunohistochemical positivity for either alpha-fetoprotein, Glypican 3 or SALL4. The following were compared between GCED and CGC: age, gender, location and size of tumor, macroscopic type, ulceration, depth of invasion, lymphatic and venous invasion, positive horizontal and vertical margin, curative resection rate. RESULTS Six cases (5 males, 1 female; mean age 75.7 years; 6 lesions) of early gastric cancer with a GCED component and 186 cases (139 males, 47 females; mean age 72.7 years; 209 lesions) of early stage CGC were investigated. Mean tumor diameters were similar but rates of submucosal invasion, lymphatic invasion, venous invasion, and non-curative resection were higher in GCED than CGC (66.6% vs 11.4%, 33.3% vs 2.3%, 66.6% vs 0.4%, 83.3% vs 11% respectively, P < 0.01). Deep submucosal invasion was not revealed endoscopically or by preoperative biopsy. Histologically, in GCED the superficial mucosal layer was covered with a CGC component. The GCED component tended to exist in the deeper part of the mucosa to the submucosa by lymphatic and/or venous invasion, without severe stromal reaction. In addition, Glypican 3 was the most sensitive marker for GCED (positivity, 83.3%), immunohistochemically. CONCLUSION Even in the early stage GCED has high malignant potential, and preoperative diagnosis is considered difficult. Endoscopists and pathologists should know the clinicopathological features of this highly malignant type of cancer.


Biomedical Reports | 2017

Efficacy of a potassium‑competitive acid blocker for improving symptoms in patients with reflux esophagitis, non‑erosive reflux disease, and functional dyspepsia

Daisuke Asaoka; Akihito Nagahara; Mariko Hojo; Kenshi Matsumoto; Hiroya Ueyama; Kohei Matsumoto; Kentaro Izumi; Tsutomu Takeda; Hiroyuki Komori; Yoichi Akazawa; Yuji Shimada; Taro Osada; Sumio Watanabe

The aim of the present study was to investigate the efficacy of a potassium-competitive acid blocker (PCAB) named vonoprazan (VPZ) for improving symptoms in patients with reflux esophagitis (RE), non-erosive reflux disease (NERD), and functional dyspepsia (FD). A hospital-based, retrospective study of outpatients in our department (Department of Gastroenterology, University of Juntendo, Tokyo, Japan) between March 2015 and August 2016 was performed. The patients who were experiencing heartburn, acid regurgitation, gastric pain, and/or a heavy feeling in the stomach of at least moderate severity at baseline were treated with 20 mg VPZ once daily for 4 weeks. The patients completed the global overall symptom (GOS) scale to determine their symptom severity at baseline and after the 4 week treatment period. The proportions of patients with RE, NERD, and FD achieving improvement of their symptoms, defined as a GOS scale score of 1 (‘no problem’) or 2 (‘minimal problem’), were evaluated. During 4 weeks of VPZ therapy, changes in the gastroesophageal reflux disease (GERD) score, which was defined as the total points for heartburn and acid regurgitation on the GOS scale in patients with RE and NERD, and in the FD score, which was defined as the total points for gastric pain and a heavy feeling in the stomach on the GOS scale in patients with FD, were also evaluated. A total of 88 eligible cases were included in the present study, comprising 20 patients with RE, 25 patients with NERD, and 43 patients with FD. The rates of symptomatic improvement in patients with RE, NERD, and FD were 75.0, 60.0, and 48.8%, respectively. For the patients who were first administered VPZ, the rates of symptomatic improvement were 90.9, 66.7, and 58.8% in patients with RE, NERD, and FD, respectively. For those patients who were resistant to 8 weeks of proton pump inhibitor therapy, the rates of symptomatic improvement were 55.6, 53.8, and 42.3% in patients with RE, NERD, and FD, respectively. The GERD score in patients with RE and NERD, and the FD score in FD patients, were decreased after 4 weeks of VPZ therapy (P<0.01). In patients with RE, NERD and FD, the possibility that PCAB may be used as a novel therapeutic drug was suggested. However, the number of study subjects was small; therefore, further, larger and prospective studies are required.


Therapeutics and Clinical Risk Management | 2016

Association of medications for lifestyle-related diseases with reflux esophagitis.

Daisuke Asaoka; Akihito Nagahara; Mariko Hojo; Kenshi Matsumoto; Hiroya Ueyama; Kohei Matsumoto; Kentaro Izumi; Tsutomu Takeda; Hiroyuki Komori; Yoichi Akazawa; Yuji Shimada; Taro Osada; Sumio Watanabe

Background Because of a change in lifestyle, especially adoption of westernized eating habits, lifestyle-related diseases have become increasingly prevalent. The aim of this study was to investigate the association of medications for lifestyle-related diseases with reflux esophagitis (RE). Methods We conducted a hospital-based, cross-sectional retrospective study of consecutive outpatients who received an upper gastrointestinal endoscopy in our department from February 2008 to November 2014, which was performed by one specialist who was a member of the Japan Gastroenterological Endoscopy Society. We investigated the patient profile, Helicobacter pylori (H. pylori) infection status, medications for lifestyle-related diseases (including calcium channel blockers, statins, and bisphosphonates), and upper gastrointestinal endoscopic findings (RE, hiatal hernia, Barrett’s mucosa, and endoscopic gastric mucosal atrophy [EGA]). Patients with gastrectomy, peptic ulcer disease, gastric or esophageal malignant disease, and those who used proton pump inhibitors or histamine-2 receptor antagonists were excluded. We divided the subjects into a group without RE (RE(−)) and a RE (RE(+)) group as judged by endoscopy, and investigated the risk factors for RE. Results Of 1,744 consecutive cases, 590 cases (300 males and 290 females; mean age 60.5±13.2 years) were eligible. RE(−) and RE(+) cases numbered 507 and 83, respectively. Bivariate analysis showed significant positive associations of RE with male sex, body mass index (BMI), calcium channel blockers, Barrett’s mucosa, hiatal hernia and negative associations of RE with H. pylori positivity, EGA. Multivariate analysis showed significant positive associations of RE with BMI (odds ratio [OR]: 1.20, 95% confidence interval [95% CI]: 1.10–1.29), use of calcium channel blockers (OR: 2.12, 95% CI: 1.16–3.87), Barrett’s mucosa (OR: 2.97, 95% CI: 01.64–5.38), hiatal hernia (OR: 3.13, 95% CI: 1.79–5.47) and negative associations of RE with H. pylori positivity (OR: 0.20, 95% CI: 0.07–0.57), use of statins (OR: 0.42, 95% CI: 0.18–0.96), and EGA (OR: 0.83, 95% CI: 0.70–0.98). Conclusion Calcium channel blockers were positively associated with RE and statins were negatively associated with RE, while bisphosphonates were not associated with RE.


Biomedical Reports | 2016

Efficacy of alfacalcidol and alendronate on lumbar bone mineral density in osteoporotic patients using proton pump inhibitors

Daisuke Asaoka; Akihito Nagahara; Mariko Hojo; Kenshi Matsumoto; Hiroya Ueyama; Kohei Matsumoto; Kentaro Izumi; Tsutomu Takeda; Hiroyuki Komori; Yoichi Akazawa; Yuji Shimada; Taro Osada; Sumio Watanabe

It has been indicated that proton pump inhibitor (PPI) use is associated with a loss of the anti-fracture efficacy of alendronate (AD). However, there are few prospective studies that have investigated the efficacy of AD on lumbar bone mineral density (BMD) in osteoporotic patients who are using PPIs. Thus, the aim of the present study was to investigate the efficacy of alfacalcidol (AC) and AD on lumbar BMD in osteoporotic patients using PPIs. A prospective, randomized, active control study enrolled such osteoporotic patients (age, ≥50 years). The patients were randomly assigned to receive AC (1 µg/day) or AD (35 mg/week) and were followed up for one year. Patient profiles were maintained, and lumbar BMD, bone-specific alkaline-phosphatase (BAP) and collagen type-I cross-linked N-telopeptide (NTX), upper gastrointestinal endoscopy results, and the frequency scale for the symptoms of gastroesophageal reflux disease (FSSG) were evaluated. Percentage changes in lumbar BMD, NTX, BAP, and change in FSSG score from baseline to the end of one year of treatment were investigated. Sixteen patients were eligible for analysis (eight assigned to receive AC, eight assigned to receive AD). The percentage change in lumbar BMD from baseline to the end of treatment was −0.4±4.0% for the AC group vs. 6.8±6.3% for the AD group (P=0.015). No significant percentage change of BAP and NTX between the two groups was observed. Subsequent to one year of treatment, the FSSG score did not change from the baseline values for either study group, and no new bone fractures or esophagitis were observed in either group of patients. The findings demonstrated that in osteoporotic patients using concomitant PPIs, there was a greater increase in lumbar BMD after one year of treatment with AD compared with AC. However, the number of study subjects was small; thus, further, large prospective studies are required to determine the effect of AD in osteoporotic patients using concomitant PPIs.


Gastroenterology Research and Practice | 2018

Effect of Esophageal Endoscopic Submucosal Dissection on Motility and Symptoms: A Prospective Study

Tsutomu Takeda; Kenshi Matsumoto; Akihito Nagahara; Hiroyuki Komori; Yoichi Akazawa; Yuta Nakagawa; Kentaro Izumi; Kohei Matsumoto; Hiroya Ueyama; Yuji Shimada; Daisuke Asaoka; Mariko Hojo; Takashi Yao; Sumio Watanabe

Background Endoscopic submucosal dissection (ESD) of esophageal tumors can cause stenosis, yet the effect of esophageal ESD on motility remains unclarified. This study aimed to compare esophageal motility and symptoms, before and after ESD, using high-resolution manometry (HRM) and symptom scoring. Methods Twenty-eight patients with 35 cT1a cancers were prospectively enrolled between December 2014 and February 2016. Pre- and post-ESD symptom score and HRM were recorded. Based on circumferential resection (CR), patients were divided into group A (n = 17, <2/3 CR) or B (n = 11, 2/3 CR or greater). HRM parameters evaluated were distal contractile integral (DCI), contractile front velocity (CFV), intrabolus pressure, integrated relaxation pressure, distal latency, and peristaltic breaks. Results Symptom scores worsened after ESD in 8/11 patients in group B, and 0/17 patients in group A. There was no significant difference in any HRM parameter after ESD in the whole study group but mean DCI tended to increase (p = 0.07). In group B, DCI increased significantly after ESD (p = 0.04), and CFV tended to decrease after ESD (p = 0.08). Conclusions DCI tended to increase after esophageal ESD. ESD affected the symptom score and esophageal motility in cases with 2/3 CR or greater. This trial is registered with UMIN000015829.


Digestion | 2018

Improved Visibility of Barrett’s Esophagus with Linked Color Imaging: Inter- and Intra-Rater Reliability and Quantitative Analysis

Tsutomu Takeda; Akihito Nagahara; Kei Ishizuka; Shoki Okubo; Keiichi Haga; Maiko Suzuki; Akihito Nakajima; Hiroyuki Komori; Yoichi Akazawa; Kentaro Izumi; Kohei Matsumoto; Hiroya Ueyama; Yuji Shimada; Kenshi Matsumoto; Daisuke Asaoka; Tomoyoshi Shibuya; Naoto Sakamoto; Taro Osada; Mariko Hojo; Shuko Nojiri; Sumio Watanabe

Background/Aims: To evaluate the usefulness of linked color imaging (LCI) and blue LASER imaging (BLI) in Barrett’s esophagus (BE) compared with white light imaging (WLI). Methods: Five expert and trainee endoscopists compared WLI, LCI, and BLI images obtained from 63 patients with short-segment BE. Physicians assessed visibility as follows: 5 (improved), 4 (somewhat improved), 3 (equivalent), 2 (somewhat decreased), and one (decreased). Scores were evaluated to assess visibility. The inter- and intra-rater reliability (intra-class correlation coefficient) of image assessments were also evaluated. Images were objectively evaluated based on L* a* b* color values and color differences (ΔE*) in a CIELAB color space system. Results: Improved visibility compared with WLI was achieved for LCI: 44.4%, BLI: 0% for all endoscopists; LCI: 55.6%, BLI: 1.6% for trainees; and LCI: 47.6%, BLI: 0% for experts. The visibility score of trainees compared with experts was significantly higher for LCI (p = 0.02). Intra- and inter-rater reliability ratings for LCI compared with WLI were “moderate” for trainees, and “moderate-substantial” for experts. The ΔE* revealed statistically significant differences between WLI and LCI. Conclusion: LCI improved the visibility of short-segment BE compared with WLI, especially for trainees, when evaluated both subjectively and objectively.


Digestion | 2018

Usefulness of Demarcation of Differentiated-Type Early Gastric Cancers after Helicobacter pylori Eradication by Magnifying Endoscopy with Narrow-Band Imaging

Yoichi Akazawa; Hiroya Ueyama; Takashi Yao; Hiroyuki Komori; Tsutomu Takeda; Kohei Matsumoto; Kenshi Matsumoto; Daisuke Asaoka; Mariko Hojo; Sumio Watanabe; Akihito Nagahara

Background/Aims: Early gastric cancer after Helicobacter pylori (Hp) eradication is difficult to demarcate. We used the vessel plus surface classification system (VSCS) to determine whether magnifying endoscopy with narrow-band imaging (ME-NBI) could demarcate differentiated-type early gastric cancers after Hp eradication, and to identify causes of an unclear demarcation line (DL). Methods: Among 100 lesions of differentiated-type early gastric cancer resected endoscopically, 34 lesions in the Hp-eradicated group and 66 in the Hp-infected group were retrospectively compared. Clinicopathological factors and ME-NBI findings, including the presence or absence of the DL, were examined. Histopathologically, histological gastritis, the surface structure at the tumor border, well-differentiated adenocarcinoma with low-grade atypia (tub1-low), and non-neoplastic epithelium (NE) coverage rate on the tumor surface and at the tumor border were evaluated. Results: DL (–) cases were more frequent in the Hp-eradicated group (11.8%, 4/34) than in the Hp-infected group (1.5%, 1/66; p < 0.05). The Hp-eradicated group had a higher NE coverage rate than the Hp-infected group (p < 0.05). All DL (–) cases had tub1-low or NE at the tumor border. Conclusion: ME-NBI with VSCS can identify the DL in most patients (88.2%) with differentiated-type early gastric cancer after Hp eradication.


Gastroenterology Research and Practice | 2015

Optimization of Deep Sedation with Spontaneous Respiration for Therapeutic Endoscopy Combining Propofol and Bispectral Index Monitoring

Kohei Matsumoto; Akihito Nagahara; Kenshi Matsumoto; Yoichi Akazawa; Hiroyuki Komori; Yuta Nakagawa; Tsutomu Takeda; Hiroya Ueyama; Yuji Shimada; Daisuke Asaoka; Mariko Hojo; Sumio Watanabe

Background/Aims. This study aimed to establish optimal propofol anesthesia for therapeutic endoscopy, which has not been established. Methodology. We retrospectively investigated data on 89 patients who underwent upper-GI endoscopic submucosal dissection or endoscopic mucosal resection under anesthesia with propofol. Examined doses of propofol were changed according to efficacy and/or adverse events and classified into 5 periods. A bispectral index (BIS) monitor was used at Period 5 to decrease the incidence of adverse events caused by oversedation. The initial dose of propofol was administered after bolus injection of pethidine hydrochloride (0.5 mg/kg), and 1.0 mL of propofol was added every minute until the patients fell asleep. Continuous and bolus infusion were performed to maintain sedation. When the patient moved or an adverse event occurred, the maintenance dose examined was increased or decreased by 5 mL/h regardless of body weight. Results. Dose combinations (introduction : maintenance) and patient numbers for each period were as follows: Period 1 (n = 27), 0.5 mg/kg : 5 mg/kg/h; Period 2 (n = 11), 0.33 mg/kg : 3.3 mg/kg/h; Period 3 (n = 7), 0.5 mg/kg : 3.3 mg/kg/h; Period 4 (n = 14), 0.5 mg/kg : 2.5 mg/kg/h; Period 5 (n = 30), 0.5 mg/kg : 2.5 mg/kg/h, using BIS monitor. During Period 5, an adverse event occurred in 10.0% of patients, which was lower than that for Periods 1–4. Conclusions. Period 5 propofol anesthesia with BIS protocol could be safe and useful for therapeutic endoscopy under deep sedation with spontaneous respiration.


Gastroenterology | 2018

Su1232 - Comprehensive Analysis using Next Generation Sequencing of Gastric Adenocarcinoma of Fundic Gland Type

Hiroya Ueyama; Takuo Hayashi; Tsuyoshi Saito; Yoichi Akazawa; Hiroyuki Komori; Kohei Matsumoto; Kenshi Matsumoto; Mariko Hojo; Sumio Watanabe; Takashi Yao; Akihito Nagahara

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