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Dive into the research topics where Kenji Yagi is active.

Publication


Featured researches published by Kenji Yagi.


Journal of Gastroenterology and Hepatology | 2008

Tailored eradication therapy based on fecal Helicobacter pylori clarithromycin sensitivities.

Takashi Kawai; Tetsuya Yamagishi; Kenji Yagi; Mikinori Kataoka; Kohei Kawakami; Atsushi Sofuni; Takao Itoi; Yoshihiro Sakai; Fuminori Moriyasu; Yoshiaki Osaka; Yu Takagi; Tatsuya Aoki; Emiko Rimbara; Norihisa Noguchi; Masanori Sasatsu

Background and Aim:  Helicobacter pylori (H. pylori) eradication rates using the PPI/AC regimen (proton pump inhibitor + amoxicillin + clarithromycin) are declining. We trialed tailoring eradication regimens according to clarithromycin (CAM) susceptibility.


Journal of Gastroenterology and Hepatology | 2010

Helicobacter pylori infection and reflux esophagitis in young and middle‐aged Japanese subjects

Takashi Kawai; Kei Yamamoto; Mari Fukuzawa; Tetsuya Yamagishi; Kenji Yagi; Masakatsu Fukuzawa; Mikinori Kataoka; Kohei Kawakami; Takao Itoi; Yoshihiro Sakai; Fuminori Moriyasu; Yu Takagi; Tatsuya Aoki

Background and Aims:  Helicobacter pylori infection rates are reported to be high in people over the age of 40 years, but are decreasing in younger age groups. A negative correlation has been reported between H. pylori infection and reflux esophagitis (RE).


Digestive Endoscopy | 2010

CLINICAL EVALUATION OF EMERGENCY ENDOSCOPIC HEMOSTASIS WITH BIPOLAR FORCEPS IN NON‐VARICEAL UPPER GASTROINTESTINAL BLEEDING

Mikinori Kataoka; Takashi Kawai; Kenji Yagi; Chizuko Tachibana; Hiroyuki Tachibana; Hiroko Sugimoto; Yasutaka Hayama; Kei Yamamoto; Masaya Nonaka; Takaya Aoki; Toshihiro Oshima; Mari Fujiwara; Mari Fukuzawa; Masakatsu Fukuzawa; Kouhei Kawakami; Yoshihiro Sakai; Fuminori Moriyasu

The present study was designed to evaluate the usefulness and safety of bipolar hemostatic forceps, known as a less invasive and highly safe means of thermal coagulation used for hemostasis in cases of non‐variceal upper gastrointestinal bleeding. This technique of bipolar forceps is simple, safe and unlikely to induce complications, and is therefore promising as a new technique of endoscopic hemostasis. The study involved 39 cases where hemostasis was attempted with bipolar forceps to deal with non‐variceal upper gastrointestinal bleeding, including 28 cases of gastric ulcer, six cases of duodenal ulcer, three cases of bleeding after endoscopic submucosal dissection (ESD), one case of Mallory‐Weiss syndrome and one case of postoperative bleeding from the anastomosed area. There were 34 males and five females, with a mean age of 63.6 years. Bipolar forceps were the first‐line means of hemostasis in cases of oozing bleeding (venous bleeding), pulsatile or spurting bleeding (arterial bleeding) and exposed vessels without active bleeding. The primary hemostasis success rate was 92.3%, and the re‐bleeding rate was 0%. In cases where the bleeding site was located along the tangential line or in cases where large respiration‐caused motions hampered identification of the bleeding site, hemostasis by means of coagulation was easily effected by application of electricity while the forceps were kept open and compressed the bleeding area. In addition, there were no complications. This technique of bipolar forceps is simple, safe and unlikely to induce complications, and is therefore promising as a new technique of endoscopic hemostasis.


Journal of Gastroenterology and Hepatology | 2012

Narrow‐band imaging on screening of esophageal lesions using an ultrathin transnasal endoscopy

Takashi Kawai; Yu Takagi; Kei Yamamoto; Yasutaka Hayama; Mari Fukuzawa; Kenji Yagi; Masakatsu Fukuzawa; Mikinori Kataoka; Kohei Kawakami; Takao Itoi; Fuminori Moriyasu; Jun Matsubayashi; Toshitaka Nagao

Background and Aim:  Ultrathin transnasal endoscopy, used extensively in Japan, is considered to have inferior image quality and suction performance, and questionable diagnostic performance. So the aim of the present study was to compare the diagnostic performance of white light (WL) examination and non‐magnified narrow‐band imaging (NBI) examination in screening for esophageal disorders with ultrathin transnasal endoscopy.


Digestive Endoscopy | 2013

Mucosal cutting biopsy technique for histological diagnosis of suspected gastrointestinal stromal tumors of the stomach

Mikinori Kataoka; Takashi Kawai; Kenji Yagi; Hiroko Sugimoto; Kei Yamamoto; Yasutaka Hayama; Masaya Nonaka; Takaya Aoki; Masakatsu Fukuzawa; Mari Fukuzawa; Takao Itoi; Fuminori Moriyasu

The Japanese Gastrointestinal Stromal Tumor (GIST) therapeutic guidelines recommend endoscopic ultrasound‐guided fine‐needle aspiration biopsy for histological diagnosis. However, before 2010, this technique was only carried out at a minority of medical institutions in Japan. In the present study, we investigated the usefulness of mucosal cutting biopsy.


Journal of Gastroenterology and Hepatology | 2008

Impact of transnasal ultrathin esophagogastroduodenoscopy (UT-EGD) in the evaluation of esophageal peristaltic function.

Takashi Kawai; Tetsuya Yamagishi; Kenji Yagi; Mikinori Kataoka; Kohei Kawakami; Atsushi Sofuni; Takao Itoi; Yoshihiro Sakai; Fuminori Moriyasu; Yoshiaki Osaka; Yu Takagi; Tatsuya Aoki

Background:  We used transnasal ultrathin esophagogastroduodenoscopy (UT‐EGD) to simultaneously perform realtime esophageal manometry and observe esophageal peristalsis.


Journal of Gastroenterology and Hepatology | 2015

Surveillance of short-segment Barrett's esophagus using ultrathin transnasal endoscopy

Hiroko Sugimoto; Takashi Kawai; Sakiko Naito; Kyosuke Yanagizawa; Tetsuya Yamagishi; Masakatsu Fukuzawa; Kenji Yagi; Jun Matsubayashi; Toshitaka Nagao; Hirofumi Tomiyama; Sumito Hoshino; Akihiko Tsuchida; Fuminori Moriyasu

Newly developed ultrathin transnasal endoscope, the GIF‐XP290N, makes possible a resolving power similar to the GIF‐H260 at a distance of 3 mm. We conducted surveillance of subjects with Barretts esophagus using this ultrathin transnasal endoscopy. In Japan the lower margin of the lower esophageal palisade vessels is defined the gastroesophageal junction in deep inspiration. We diagnose Barretts esophagus if columnar epithelium is present on the oral side of the gastroesophageal junction.


World Journal of Gastroenterology | 2015

Clinical impact of endoscopy position detecting unit (UPD-3) for a non-sedated colonoscopy.

Masakatsu Fukuzawa; Junichi Uematsu; Shin Kono; Sho Suzuki; Takemasa Sato; Naoko Yagi; Yuichiro Tsuji; Kenji Yagi; Chika Kusano; Takuji Gotoda; Takashi Kawai; Fuminori Moriyasu

AIM To evaluate whether an endoscopy position detecting unit (UPD-3) can improve cecal intubation rates, cecal intubation times and visual analog scale (VAS) pain scores, regardless of the colonoscopists level of experience. METHODS A total of 260 patients (170 men and 90 women) who underwent a colonoscopy were divided into the UPD-3-guided group or the conventional group (no UPD-3 guidance). Colonoscopies were performed by experts (experience of more than 1000 colonoscopies) or trainees (experience of less than 100 colonoscopies). Cecal intubation rates, cecal intubation times, insertion methods (straight insertion: shortening the colonic fold through the bending technique; roping insertion: right turn shortening technique) and patient discomfort were assessed. Patient discomfort during the endoscope insertion was scored by the VAS that was divided into 6 degrees of pain. RESULTS The cecum intubation rates, cecal intubation times, number of cecal intubations that were performed in < 15 min and insertion methods were not significantly different between the conventional group and the UPD-3-guided group. The number of patients who experienced pain during the insertion was markedly less in the UPD-3-guided group than in the conventional group. Univariate and multivariate analysis showed that the following factors were associated with lower VAS pain scores during endoscope insertion: insertion method (straight insertion) and UPD-3 guidance in the trainee group. For the experts group, univariate analysis showed that only the insertion method (straight insertion) was associated with lower VAS pain scores. CONCLUSION Although UPD-3 guidance did not shorten intubation times, it resulted in less patient pain during endoscope insertion compared with conventional endoscopy for the procedures performed by trainees.


IDCases | 2017

Positive fecal occult blood test as a diagnostic cue for Schistosoma mansoni infection in a developed country

Itaru Nakamura; Kenji Yagi; Takashi Kumagai; Nobuo Ohta

The rise in eco-tourism and travel off the beaten track have increased numbers of tourists with schistosomiasis which is seldom seen in developed countries, although this disease is considered a neglected tropical disease especially in poor communities. A Guinean male living in Japan was seen complaining of severe constipation. He was positive for fecal occult blood (FOB) and underwent colonoscopy. Colonoscopy showed petechiae of the rectal mucosa, with pathologic examination of biopsy tissue showing calcified eggs of the genus Schistosoma. Direct examination of eggs in feces and antibody tests of serum confirmed the diagnosis of schistosomiasis. The patient was administered Praziquantel (400 mg/day for 2 days) and FOB and fecal ova tests were negative after treatment. FOB tests have been reported as a useful assessment of morbidities associated with intestinal schistosomiasis. In developed countries, positive FOB result, which is used as a main examination for bowel malignant disease, are not recognized as being due to schistosomiasis. As this tropical disease is rarely present in developed countries, it may be under-diagnosed. Schistosomiasis should be included in the differential diagnosis of patients with positive FOB tests.


Hepato-gastroenterology | 2007

Comparison of the effects on cardiopulmonary function of ultrathin transnasal versus normal diameter transoral esophagogastroduodenoscopy in Japan.

Takashi Kawai; Ikuko Miyazaki; Kenji Yagi; Mikinori Kataoka; Kohei Kawakami; Tetsuya Yamagishi; Atsushi Sofuni; Takao Itoi; Fuminori Moriyasu; Yoshiaki Osaka; Yuu Takagi; Tatsuya Aoki

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Takashi Kawai

Tokyo Medical University

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Takao Itoi

Tokyo Medical University

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Masaya Nonaka

Tokyo Medical University

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Kohei Kawakami

Tokyo Medical University

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