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Dive into the research topics where Atsushi Kohyama is active.

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Featured researches published by Atsushi Kohyama.


Journal of Gastroenterology | 2006

Assessment of the Japanese Inflammatory Bowel Disease Questionnaire in patients after ileal pouch anal anastomosis for ulcerative colitis

Kazuhiro Watanabe; Yuji Funayama; Kouhei Fukushima; Chikashi Shibata; Kenichi Takahashi; Hitoshi Ogawa; Sho Haneda; Katsuyoshi Kudo; Atsushi Kohyama; Iwao Sasaki

BackgroundThe Inflammatory Bowel Disease Questionnaire (IBDQ) is the most widely used disease-specific health-related quality of life questionnaire for patients with inflammatory bowel disease. However, little has been reported about the validation of IBDQ for patients with ulcerative colitis after surgery. The aim of this study was to assess the validity and reliability of the Japanese version of IBDQ in patients with ulcerative colitis after total proctocolectomy and ileal pouch anal anastomosis (IPAA).MethodsThe validity and reliability of the Japanese IBDQ were assessed in patients with ulcerative colitis who had received IPAA in our hospital. We mailed them the Japanese IBDQ and a supplemental questionnaire on bowel function, which was developed at our institution. Internal consistency, discriminative validity, and factor validity were assessed.ResultsOf the 121 patients to whom we sent the questionnaires, 64 patients (53%) participated in this study. The Japanese IBDQ scores correlated well with Cronbach’s alpha value (0.800 to 0.923) and daily life satisfaction score (Pearson’s r, 0.492 to 0.700). The total IBDQ score and two subscale scores of the IBDQ, “bowel symptoms” and “systemic symptoms,” correlated well with daily bowel-movement frequency (Pearson’s r, −0.256 to −0.329). Factor analysis revealed a four-factor structure, and all correlations among factors were moderately positive (0.337 to 0.465). Although the factor distribution was not clearly divided into the four IBDQ subscales, these four factors showed a marked tendency to represent the IBDQ subscales independently.ConclusionsThe Japanese IBDQ is a valid and reliable instrument for the assessment of Japanese patients with ulcerative colitis after IPAA.


Digestive Diseases and Sciences | 2012

A Shift from Colon- to Ileum-Predominant Bacteria in Ileal-Pouch Feces Following Total Proctocolectomy

Manami Hinata; Atsushi Kohyama; Hitoshi Ogawa; Sho Haneda; Kazuhiro Watanabe; Hideyuki Suzuki; Chikashi Shibata; Yuji Funayama; Kenichi Takahashi; Iwao Sasaki; Kouhei Fukushima

BackgroundWe previously investigated fecal flora of the pouch after total proctocolectomy using terminal restriction fragment polymorphism analysis. Although the results of the cluster analysis demonstrated clearly that bacterial populations, including an unidentified bacteria generating a 213-bp PCR fragment, moved toward a colon-like community in the pouch, it did not track changes in the individual species of fecal bacteria.AimsThe aim of the present study was to estimate genome copy number of ten bacterial species, clusters, groups, or subgroups (including the bacteria generating 213-bp fragment in the previous study) in feces samples from pouches at various times following ileostomy closure.MethodsA total of 117 stool samples were collected from patients with ulcerative colitis after surgery as well as healthy volunteers. We used real-time polymerase chain reaction of the 16S rRNA gene to estimate genome copy numbers for the nine bacterial populations and the bacteria generating 213-bp fragment after identification by DNA sequencing.ResultsWe demonstrated a time-dependent increase in the number of anaerobic and colon-predominant bacteria (such as Clostridium coccoides, C. leptum, Bacteroides fragilis and Atopobium) present in proctocolectomy patients after stoma closure. In contrast, numbers of ileum-predominant bacterial species (such as Lactobacillus and Enterococcus faecalis) declined.ConclusionsOur data confirm previous findings that fecal flora in the pouch after total proctocolectomy changes significantly, and further demonstrate that the number and diversity of ileal bacteria decreases while a more colon-like community develops. The present data are essential for the future analysis of pathological conditions in the ileal pouch.


Journal of Gastrointestinal Surgery | 2008

The glucagon provocative test for the diagnosis and treatment of Zollinger-Ellison syndrome.

Chikashi Shibata; Yuji Funayama; Kouhei Fukushima; Tatsuya Ueno; Atsushi Kohyama; Kennichi Satoh; Tooru Shimosegawa; Tetsuya Yamagiwa; Iwao Sasaki

ObjectiveOur aim was to determine whether the glucagon provocative test could be used in place of secretin test in patients with gastrinoma.MethodsThree patients with gastrinoma underwent the following examinations: (1) preoperative intravenous glucagon test to enable a definitive diagnosis, (2) intra-arterial glucagon injection test to localize the tumor, and (3) intraoperative and postoperative intravenous glucagon test to confirm the completeness of the resection.ResultsSerum gastrin levels increased in response to intravenous glucagon in all three patients preoperatively. Computed tomography scans revealed a tumor in the lesser omentum, pancreatic head, and the pancreatic uncinate in cases 1, 2, and 3, respectively. Intra-arterial glucagon test revealed that the feeding artery for the tumor was the left gastric artery in case 1 and the superior mesenteric artery in case 3. Resection of the remnant stomach with tumor, pancreaticoduodenectomy with portal vein resection, and enucleation of the tumor were performed in cases 1, 2, and 3, respectively. Serum gastrin levels did not increase in response to intravenous glucagon intraoperatively and postoperatively in cases 1 and 3. Although intravenous glucagon caused a slight increase in serum gastrin in case 2, no recurrent tumors were evident.ConclusionThese results indicate that the glucagon provocative test is a suitable alternative to testing with secretin, which is not commercially available in Japan.


Journal of Gastrointestinal Surgery | 2006

Factors Affecting the Bowel Function after Proctocolectomy and Ileal J Pouch–Anal Anastomosis for Ulcerative Colitis

Chikashi Shibata; Yuji Funayama; Kouhei Fukushima; Kenichi Takahashi; Fumito Saijo; Munenori Nagao; Sho Haneda; Kazuhiro Watanabe; Katsuyoshi Kudoh; Atsushi Kohyama; Iwao Sasaki

The aim was to study determinants of postoperative bowel function after restorative proctocolectomy for ulcerative colitis. Medical records of patients who underwent proctocolectomy with ileal J pouch-anal anastomosis (IPAA) in two- or three-stage operations and whose status of defecation was known via a questionnaire were retrospectively reviewed. Bowel function, including stool frequency, stool consistency, and degree of nighttime soiling, was correlated with age at the time of surgery, time after ileostomy closure, mean resting anal pressure, longitudinal length of ileal J pouch, and duration of fecal diversion by using univariate and multivariate analyses. Stool frequency decreased significantly with time after ileostomy closure in both univariate and multivariate analyses. Stool frequency tended to be less in patients having a long J pouch, but the correlation was not significant (P=0.071) in univariate analysis. Nighttime soiling ameliorated with time after ileostomy closure in multivariate, but not univariate, analysis. Deterioration of nighttime soiling was seen in patients whose duration for fecal diversion was long, both in univariate (P=0.068) and multivariate (P=0.052) analyses. Stool consistency was related to none of the five factors investigated. These results indicate that as the time after surgery increases, stool frequency decreases and nighttime soiling ameliorates. Delaying ileostomy closure because of anticipated postoperative incontinence does not significantly alter postoperative continence.


Cancer Research | 2014

Abstract 2832: Single nucleotide polymorphisms of DPYD and MTHFR predict adverse events associated with 5-fluorouracil in patients with gastrointestinal cancer

Masahide Toshima; Shinobu Ohnuma; Michiiro Tanaka; Koh Miura; Wataru Fujibuchi; Taiki Kajiwara; Toshihiro Komura; Hiroaki Musha; Sho Haneda; Katsuyoshi Kudoh; Atsushi Kohyama; Takeshi Naitoh; Michiaki Unno

Purpose The aim of this study was to investigate the association between 5-fluorouracil (5-FU)-related adverse events (AEs) in Japanese patients with gastrointestinal cancer treated with 5-FU and the patient genotypes DPYD, MTHFR, OPRT, and TYMS. Methods Sequence analyses of 33 gene polymorphisms in four genes were performed using genomic DNA extracted from peripheral blood mononuclear cells of 103 patients with gastric (n = 34) or colorectal (n = 69) cancer. The 5-FU-related AEs of 157 regimens in these 103 patients were evaluated based on the medical records of patients in each of three groups: the intravenous administration group (i.v. group, n = 51), oral administration group (p.o. group, n = 106), and all-regimens group (both i.v. and p.o. group, n = 157). The associations between the incidence of AEs and each genotype were statistically analyzed. Results Six single-nucleotide polymorphisms (SNPs) were identified (three SNPs in DPYD: c.496A>G, c.1905+1G>A, and c.2303C>A; two SNPs in MTHFR: c.677C>T and c.1298A>C; and one SNP in OPRT: c.638G>C). Among them, the patients in the all-regimens group carrying any one of three DPYD SNPs showed statistically significant associations with the incidence of AEs of any type and fatigue. Furthermore, the MTHFR SNP c.1298A>C was significantly associated with the incidence of neutropenia. A similar trend was observed in the p.o. group, but not in the i.v. group. Conclusion These findings suggest that the DPYD SNPs c.496A>G, c.1905+1G>A, and c.2303C>A and the MTHFR SNP c.1298A>C may be predictive factors for the occurrence of severe 5-FU-related AEs. Citation Format: Masahide Toshima, Shinobu Ohnuma, Michiiro Tanaka, Koh Miura, Wataru Fujibuchi, Taiki Kajiwara, Toshihiro Komura, Hiroaki Musha, Sho Haneda, Katsuyoshi Kudoh, Atsushi Kohyama, Takeshi Naitoh, Michiaki Unno. Single nucleotide polymorphisms of DPYD and MTHFR predict adverse events associated with 5-fluorouracil in patients with gastrointestinal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2832. doi:10.1158/1538-7445.AM2014-2832


Cancer Research | 2014

Abstract 631: Gastrointestinal toxicities of 5-FU increase the proportion of regulatory T cells in murine intestinal tract: Advantages of alternate-day S-1 administration

Taiki Kajiwara; Koh Miura; Shinobu Ohnuma; Tetsuhiko Shirasaka; Toshihiro Komura; Masahide Toshima; Atsushi Kohyama; Katsuyoshi Kudoh; Sho Haneda; Hiroaki Musha; Fuyuhiko Motoi; Yu Katayose; Takeshi Naitoh; Michiaki Unno

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA [Introduction] 5-fluorouracil (5-FU), a core anticancer agent used for various malignancies, induces gastrointestinal (GI) toxicities. The tegafur-based oral 5-FU prodrug S-1 is recognized to be a key drug for GI and other malignancies in Japan and some Asian countries. S-1 was developed to potentiate antitumor activity of 5-FU and to reduce gastrointestinal toxicities. However, S-1 also causes GI toxicities by the standard daily regimen. On the other hand, the alternate-day administration of S-1 has been proposed to minimize toxicities without reducing the anticancer efficacy of 5-FU. Recently, tumor immunology has greatly advanced, and the role of T cells in antitumor immunity has been well investigated. However, it remains unknown how GI toxicities of 5-FU affect T cell subsets related to antitumor immunity. [Purpose] The purpose of this study is to clarify the influence of 5-FU mediated GI toxicities on T cell subsets related to antitumor immunity. [Methods] Two regimens of S-1 were compared to evaluate the impact of GI toxicities of 5-FU on T cells using Balb/c mice. The first regimen consisted of the daily administration of S-1 (daily group) as a 5-FU GI toxicity model, and the second regimen consisted of the alternate-day administration of S-1 (alternate-day group) as a 5-FU non-GI toxicity model. S-1 was orally administered at a dose of 12 mg/kg as tegafur. We then investigated the degree of GI toxicities and T cell subsets in intra-abdominal lymphoid tissues (spleen, mesenteric lymph node and gut-associated lymphoid tissue). [Results] Only the daily group exhibited body weight loss and GI toxicities. Flow cytometric analyses demonstrated that the proportion of regulatory T cells in the intestinal tissue was 6-fold higher in the daily group than that in the control group, and the proportions of Th1 cells in the daily group showed a decreasing trend. However, the alternate-day group exhibited almost no changes in the proportions of T cell subsets. [Conclusions] GI toxicities of 5-FU increase the proportion of regulatory T cells in intestinal tissue and decrease the proportions of Th1 cells systemically, which suggests that GI toxicities of 5-FU have a negative influence on T cell-dependent antitumor immunity, and the alternate-day administration of S-1 has neither GI toxicities nor the influence on T cell subsets, which suggests that 5-FU regimens without GI toxicities are more useful than those with GI toxicities from the viewpoint of antitumor immunity. Citation Format: Taiki Kajiwara, Koh Miura, Shinobu Ohnuma, Tetsuhiko Shirasaka, Toshihiro Komura, Masahide Toshima, Atsushi Kohyama, Katsuyoshi Kudoh, Sho Haneda, Hiroaki Musha, Fuyuhiko Motoi, Yu Katayose, Takeshi Naitoh, Michiaki Unno. Gastrointestinal toxicities of 5-FU increase the proportion of regulatory T cells in murine intestinal tract: Advantages of alternate-day S-1 administration. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 631. doi:10.1158/1538-7445.AM2014-631


Cancer Research | 2014

Abstract 792: Usefulness of alternate-day administration of S-1 and leucovorin in a xenograft mouse model of colorectal cancer: A shorter drug-free interval leads to more efficient antitumor effects

Toshihiro Komura; Shinobu Ohnuma; Koh Miura; Tetsuhiko Shirasaka; Taiki Kajiwara; Katsuyoshi Kudoh; Sho Haneda; Masahide Toshima; Atsushi Kohyama; Hiroaki Musha; Takeshi Naitoh; Yu Katayose; Michiaki Unno

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA [Background] A clinical trial of S-1 with leucovorin (S-1/LV) in metastatic colorectal cancer (CRC) patients demonstrated promising efficacy; however, the gastrointestinal toxicities were so severe that it has not been applied in the clinical setting. On the other hand, alternate-day administration of S-1 has been proposed to attenuate the adverse events without reducing its anticancer activity. The aim of this study was to confirm the feasibility of alternate-day administration of S-1/LV in in vivo xenograft tumor models. [Methods] Mice were treated with S-1/LV either in a daily group (two weeks of administration followed by two weeks of withdrawal) or an alternate-day group (administration on alternate days for four weeks), then the mice of both groups were sacrificed and the xenograft tumors were resected. To assess the adverse reactions, the body weight changes, the condition of feces, mucosal injury of small intestine and myelosuppression were compared between both groups. Furthermore, tumor volume, tumor growth inhibition (TGI) and the expression of Ki67, TUNEL, cIAP2 and XIAP were analyzed to evaluate the antitumor activity and tumor apoptosis. [Results] Severe weight loss, diarrhea, mucosal injury and myelosuppression were observed only in the daily group; however, no adverse reactions were observed in the alternate-day group, except slight myelosuppression. The TGI in the alternate-day group was better than that in the daily group, possibly resulting from apoptosis of tumor cells due to the suppression of cIAP2. [Conclusion] Our findings suggest that alternate-day administration of S-1/LV for CRC treatment can achieve higher antitumor activity without severe adverse reactions. Therefore, we propose that clinical trials with this regimen should be conducted in CRC patients. Citation Format: Toshihiro Komura, Shinobu Ohnuma, Koh Miura, Tetsuhiko Shirasaka, Taiki Kajiwara, Katsuyoshi Kudoh, Sho Haneda, Masahide Toshima, Atsushi Kohyama, Hiroaki Musha, Takeshi Naitoh, Yu Katayose, Michiaki Unno. Usefulness of alternate-day administration of S-1 and leucovorin in a xenograft mouse model of colorectal cancer: A shorter drug-free interval leads to more efficient antitumor effects. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 792. doi:10.1158/1538-7445.AM2014-792


Surgery | 2009

Bacterial population moves toward a colon-like community in the pouch after total proctocolectomy.

Atsushi Kohyama; Hitoshi Ogawa; Yuji Funayama; Kenichi Takahashi; Yoshimi Benno; Katsunori Nagasawa; Shinichi Tomita; Iwao Sasaki; Kouhei Fukushima


Anticancer Research | 2013

Adenocarcinoma Associated with Perianal Fistulas in Crohn's Disease

Hitoshi Ogawa; Sho Haneda; Chikashi Shibata; Koh Miura; Munenori Nagao; Shinobu Ohnuma; Atsushi Kohyama; Michiaki Unno


Digestive Diseases and Sciences | 2007

Effect of Calcium Polycarbophil on Bowel Function After Restorative Proctocolectomy for Ulcerative Colitis: A Randomized Controlled Trial

Chikashi Shibata; Yuji Funayama; Kouhei Fukushima; Kenichi Takahashi; Hitoshi Ogawa; Sho Haneda; Kazuhiro Watanabe; Katsuyoshi Kudoh; Atsushi Kohyama; Keiichi Hayashi; Iwao Sasaki

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Chikashi Shibata

Tohoku Pharmaceutical University

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