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Dive into the research topics where Natsumi Hatakeyama is active.

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Featured researches published by Natsumi Hatakeyama.


Alimentary Pharmacology & Therapeutics | 2005

New strategy of therapy for functional dyspepsia using famotidine, mosapride and amitriptyline

Michiro Otaka; Mario Jin; Masaru Odashima; Tamotsu Matsuhashi; Isao Wada; Youhei Horikawa; Koga Komatsu; Reina Ohba; Jinko Oyake; Natsumi Hatakeyama; Sumio Watanabe

Background : In functional gastrointestinal (GI) disorders including functional dyspepsia (FD) and irritable bowel syndrome (IBS), there might be no small extent of contributions of psychosomatic factors. As a therapy for IBS patients, the effectiveness of antidepressants has been reported.


Digestive Diseases and Sciences | 2007

Large Brunner’s Gland Hyperplasia Treated with Modified Endoscopic Submucosal Dissection

Reina Ohba; Michiro Otaka; Mario Jin; Masaru Odashima; Tamotsu Matsuhashi; Youhei Horikawa; Natsumi Hatakeyama; Nobuya Mimori; Nobukatsu Kinoshita; Shigeto Koizumi; Taiji Takahashi; Sumio Watanabe

Brunner’s glands are mucosal and submucosal alkalinesecreting glands that are most commonly located in the duodenum, especially in the first part of the duodenum, although they are rarely found in the pylorus and jejunum. Hyperplasia of these glands is normally seen in 2% of upper gastrointestinal (GI) endoscopies [1]. Five percent to 10% of benign duodenal tumors are caused by lesions of Brunner’s gland [2]. They are usually asymptomatic and lesions are discovered incidentally but they can occasionally cause symptoms such as GI hemorrhage and obstruction when they reach sizes >2 cm [3, 4]. In this paper, we report a case of large hyperplasia of Brunner’s gland successfully treated by modified endoscopic submucosal dissection (ESD) technique.


Journal of Gastroenterology and Hepatology | 2005

Selective adenosine A2A receptor agonist, ATL‐146e, attenuates stress‐induced gastric lesions in rats

Masaru Odashima; Michiro Otaka; Mario Jin; Koga Komatsu; Isao Wada; Tamotsu Matsuhashi; Youhei Horikawa; Natsumi Hatakeyama; Jinko Oyake; Reina Ohba; Joel Linden; Sumio Watanabe

Background:  Activation of adenosine A2A receptors reduces the production of various pro‐inflammatory cytokines and suppresses neutrophil activation. Water‐immersion restraint is well known to cause gastric mucosal lesions due to stress. The pathogenesis of stress‐induced gastric mucosal lesions is characterized by activation of inflammatory cells and production of inflammatory cytokines. Agonists of adenosine A2A receptors are known to be anti‐inflammatory, but the effects of these compounds on the development of gastric mucosal lesions has not been reported. In the present study, the effect of a potent and selective adenosine A2A receptor agonist, ATL‐146e, on water‐immersion stress‐induced gastric mucosal lesions was studied.


Journal of Gastroenterology | 2005

Selective A2A adenosine agonist ATL-146e attenuates acute lethal liver injury in mice

Masaru Odashima; Michiro Otaka; Mario Jin; Koga Komatsu; Isao Wada; Tamotsu Matsuhashi; Youhei Horikawa; Natsumi Hatakeyama; Jinko Oyake; Reina Ohba; Joel Linden; Sumio Watanabe

Backgroundd-Galactosamine (GalN)/lipopolysaccharide (LPS)-induced liver injury is an experimental model of fulminant hepatic failure in which tumor necrosis factor-α (TNF-α) plays a pivotal role. We examined the effects of a highly selective adenosine A2A receptor agonist (ATL-146e) on GalN/LPS-induced fulminant hepatic failure.MethodsMice were given an intraperitoneal dose of GalN (800 mg/g body weight)/LPS (100 ng/g body weight) with and without ATL-146e (0.01 µg/kg) treatment. Liver injury was assessed biochemically and histologically. Also, TNF-α levels in the serum were determined.ResultsThe serum liver enzyme (ALT) level in vehicle-treated mice was 20 960 ± 2800 IU/ml and was reduced by 63% to 7800 ± 1670 IU/ml by treatment with 0.01 µg/kg per minute ATL146e, P < 0.05. Treatment with ATL-146e significantly reduced serum TNF-α and greatly reduced inflammation assessed by histopathologic examination compared with control mice treated with GalN/LPS. ATL-146e also reduced lethality at 12 h from 65% to 13%.ConclusionThe present findings suggest that the highly selective adenosine A2A receptor agonist (ATL-146e) prevents endotoxin-induced lethal liver injury by suppression of TNF-α secretion.


Journal of Gastroenterology | 2006

Effect of cilostazol, a selective type-III phosphodiesterase inhibitor, on water-immersion stress-induced gastric mucosal injury in rats

Reina Ohba; Michiro Otaka; Masaru Odashima; Mario Jin; Koga Komatsu; Noriaki Konishi; Isao Wada; Youhei Horikawa; Tamotsu Matsuhashi; Jinko Oyake; Natsumi Hatakeyama; Sumio Watanabe

BackgroundCilostazol, a specific type-III phosphodiesterase inhibitor, is widely used for the treatment of ischemic symptoms of peripheral vascular disease. Recent studies have reported that the mechanism of cilostazol is related to the suppression of pro-inflammatory cytokine production and improvement of local microcirculation disturbances. The pathogenesis of stress-induced gastric mucosal lesions is characterized by the activation of inflammatory cells and the production of inflammatory cytokines. The effects of cilostazol on the development of gastric mucosal lesions have not been reported. In the present study, we examined the effect of a cilostazol on water-immersion stress-induced gastric mucosal lesions.MethodsRats were subjected to water-immersion stress with or without pretreatment with a single intraperitoneal injection of the selective type-III phosphodiesterase inhibitor, cilostazol. We measured the gastric mucosal lesion and the concentrations of myeloperoxidase (MPO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1), as an index of neutrophil accumulation and pro-inflammatory cytokine production.ResultsCilostazol ameliorated the gastric mucosal injury induced by water-immersion stress (P < 0.001). The gastric contents of MPO, TNF-α, IL-1β, and CRO/CINC-1 were all increased after water-immersion stress and were reduced to almost normal levels by cilostazol.ConclusionsIn this study, we demonstrated that a selective type-III phosphodiesterase inhibitor, cilostazol, inhibited stress-induced gastric inflammation and damage via suppressing the production of pro-inflammatory cytokines. Cilostazol may be useful for preventing gastric mucosal lesions.


Journal of Gastroenterology and Hepatology | 2005

Specific type IV phosphodiesterase inhibitor ameliorates thioacetamide-induced liver injury in rats

Tamotsu Matsuhashi; Michiro Otaka; Masaru Odashima; Mario Jin; Koga Komatsu; Noriaki Konishi; Isao Wada; Toshihiro Sato; Youhei Horikawa; Reina Ohba; Jinko Oyake; Natsumi Hatakeyama; Sumio Watanabe

Background and Aims:  Rolipram  is a specific type IV phosphodiesterase inhibitor that suppresses the activity of immune cells and the production of pro‐inflammatory cytokines. In this study, we assessed the effect of rolipram on acute liver injury using thioacetamide (TAA)‐induced liver injury in rats as a model.


Digestive Diseases and Sciences | 2007

MEK Activation Suppresses CPT11-Induced Apoptosis in Rat Intestinal Epithelial Cells Through a COX-2-Dependent Mechanism

Youhei Horikawa; Michiro Otaka; Koga Komatsu; Mario Jin; Masaru Odashima; Isao Wada; Tamotsu Matsuhashi; Reina Ohba; Jinko Oyake; Natsumi Hatakeyama; Raymond N. DuBois; Sumio Watanabe

Resistance to chemotherapeutic agents is one of the distinct features of cancer cells. We evaluate the role of activated MEK-ERK signaling in Camptotecin/irinotecan (CPT-11)-induced cell death using constitutively activated MEK1-transfected normal rat intestinal epithelial cells (IEC-caMEK cells). A CPT-11-induced inhibitory concentration of 50% was determined by WST assay. Apoptosis was evaluated by DNA staining and fragmented DNA analysis. Protein expressions were analyzed by western blotting. We also examined the role of cyclooxygenase-2 in the cell systems. IEC-caMEK cells possessed survival advantages compared to control cells. Apoptosis was remarkably suppressed in IEC-caMEK cells. Western blot analysis revealed increased expression of Bcl-2, Bcl-xL, Mcl-1, and COX-2 and decreased expression of Bak in IEC-caMEK cells. The COX-2 selective inhibitor ameliorated the antiapoptotic nature of IEC-caMEK cells. MEK activation suppressed CPT-11-induced apoptosis in IEC-caMEK cells via a COX-2- dependent mechanism. Therefore, MEK-ERK signaling may contribute to the drug-resistant nature of cancer cells.


Gastrointestinal Endoscopy | 2014

Advanced feasibility of endoscopic submucosal dissection for the treatment of gastric tube cancer after esophagectomy

Shin Tawaraya; Mario Jin; Tamotsu Matsuhashi; Yusato Suzuki; Masayuki Sawaguchi; Noboru Watanabe; Kengo Onochi; Shigeto Koizumi; Natsumi Hatakeyama; Reina Ohba; Hirosato Mashima; Hirohide Ohnishi

The incidence of esophageal cancer is increasing worldwide. However, progress in surgical techniques and the development of novel therapeutic modalities such as adjuvant chemoradiation therapy combined with surgery have improved the postoperative survival up to 34% to 51% at 5 years. Therefore, long-term survival cases are no longer rare. Generally, gastric tubes are substituted for the reconstitution after the esophagectomy for the treatment of esophageal cancer. In association with the increase in the number of long-term follow-up cases after esophagectomy, the occurrence of secondary malignancies such as adenocarcinoma arising in gastric tubes has been reported. Until a decade ago, repeat surgery was considered for the treatment of adenocarcinoma in gastric tubes. However, this did not achieve satisfactory clinical outcomes because of its high operative risks. Recently, the use of EMR has been emphasized for treatment in patients with superficial lesions. Although the clinical risks of EMR associated with gastric tube cancer (GTC) treatment are significantly lower than those associated with surgery, EMR cannot always be used to resect GTC completely because of its technical limitations regarding the tumor sizes. Therefore, endoscopic submucosal dissection (ESD) is currently used as a therapeutic option for treating GTC. However, ESD for GTC also carries limitations with respect to the anatomical features of gastric tubes, particularly the suture line and staples with the possibility of fibrosis. We therefore investigated the feasibility of


Gastrointestinal Endoscopy | 2014

The feasibility of endoscopic submucosal dissection for superficial esophageal cancer in patients with cirrhosis (with video)

Masayuki Sawaguchi; Mario Jin; Tamotsu Matsuhashi; Reina Ohba; Natsumi Hatakeyama; Shigeto Koizumi; Kengo Onochi; Yumi Yamada; Noriyoshi Kanazawa; Yuko Kimura; Shin Tawaraya; Noboru Watanabe; Yusato Suzuki; Hirosato Mashima; Hirohide Ohnishi

Endoscopic submucosal dissection (ESD) was initially developed for gastric cancer and is currently accepted as an established procedure for superficial cancer of the esophagus. The most important advantage of ESD compared with EMR is that it can provide a high en bloc resection rate and precise histologic assessment even for large lesions. On the other hand, the disadvantage of ESD is a higher risk of bleeding and perforation than for EMR. Previous reports described that esophageal ESDrelated adverse events, such as postoperative bleeding and perforation, are considerably serious risks. However, ESD for patients with cirrhosis may carry a higher risk of these adverse events because of the low platelet count, coagulopathy, and portal hypertensive gastroenteropathy, including esophageal varices, in these patients. As a result, endoscopists have been hesitant to apply ESD for the treatment of esophageal cancer in patients with cirrhosis.


Internal Medicine | 2015

True Primary Enterolith Treated by Balloon-assisted Enteroscopy

Mitsuaki Ishioka; Mario Jin; Tamotsu Matsuhashi; Suguru Arata; Yusato Suzuki; Noboru Watanabe; Masayuki Sawaguchi; Noriyoshi Kanazawa; Kengo Onochi; Natsumi Hatakeyama; Shigeto Koizumi; Hirosato Mashima; Hirohide Ohnishi

Primary enterolith is a rare condition that can induce ileus and intestinal perforation. We report the first case of a true primary enterolith treated by balloon-assisted enteroscopy. The patient presented with a small intestinal ileus. After its improvement following the insertion of an ileus tube, radiography with amidotrizoate sodium meglumine detected a round, movable defect in the ileum measuring 42 mm diameter. The patient was diagnosed with a primary enterolith based on her past history. The enterolith was fractured and removed using balloon-assisted enteroscopy. This case suggests that balloon-assisted enteroscopy may be an effective non-invasive treatment option for enteroliths.

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