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Dive into the research topics where Yasushi Iwao is active.

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Featured researches published by Yasushi Iwao.


Journal of Clinical Investigation | 1995

Interleukin 7 is produced by human intestinal epithelial cells and regulates the proliferation of intestinal mucosal lymphocytes.

Mamoru Watanabe; Yoshitaka Ueno; Tomoharu Yajima; Yasushi Iwao; Masaharu Tsuchiya; Hiromichi Ishikawa; Sadakazu Aiso; Toshifumi Hibi; Hiromasa Ishii

The interaction of mucosal lymphocytes and intestinal epithelial cells is thought to be important in regulating immune response in the intestinal mucosa, but conclusive evidence is limited. Here we demonstrate the expression of IL-7 mRNA in human intestinal mucosa by combined reverse transcription PCR and Southern blot hybridization. Immunohistochemistry and in situ hybridization confirm the presence of IL-7 in intestinal epithelial cells, especially in epithelial goblet cells. Moreover, IL-7 receptor expression in mucosal lymphocytes is demonstrated by immunohistochemistry and in situ hybridization, as well as by Southern blot and flow cytometric analysis of freshly isolated lamina propria lymphocytes. In contrast, IL-7 receptor could not be detected in the cell surface of freshly isolated PBLs. The functional activity of IL-7 receptor is demonstrated by the utility of recombinant IL-7 to stimulate the growth of lamina propria lymphocytes, and conversely inhibit CD3-dependent proliferation of these cells. In contrast, IL-7 caused no significant increase in DNA synthesis and cell numbers when added to PBLs. These findings suggest that human intestinal epithelial cells and epithelial goblet cells produce IL-7, and locally produced IL-7 may serve as a potent regulatory factor for intestinal mucosal lymphocytes.


The American Journal of Gastroenterology | 2007

Cytomegalovirus is frequently reactivated and disappears without antiviral agents in ulcerative colitis patients

Katsuyoshi Matsuoka; Yasushi Iwao; Takeshi Mori; Atsushi Sakuraba; Tomoharu Yajima; Tadakazu Hisamatsu; Susumu Okamoto; Yuichi Morohoshi; Motoko Izumiya; Hitoshi Ichikawa; Toshiro Sato; Nagamu Inoue; Haruhiko Ogata; Toshifumi Hibi

OBJECTIVE: The clinical significance of cytomegalovirus (CMV) reactivation complicating ulcerative colitis (UC) patients has been uncertain. It has therefore remained undetermined whether or not CMV reactivation should be treated in UC patients under immunosuppression. The aim of the study was to clarify the natural history of CMV reactivation in UC patients.METHODS: Sixty-nine UC patients with moderate to severe activity were enrolled in the study. All of the patients were treated with prednisolone, and/or immunosuppressants such as cyclosporine A. We sequentially monitored CMV reactivation every 2 wk up until 8 wk using the CMV antigenemia (Ag) assay and plasma quantitative real-time polymerase chain reaction (PCR) assay for CMV.RESULTS: Immunoglobulin (Ig) G for CMV was positive in 48 patients (69.6%) and negative in 21 patients (30.4%). CMV was reactivated in 25 patients out of the 48 seropositive patients (52.1%) during the study period. The CMV Ag and PCR values were low and none of the patients showed any evidence of CMV infection on biopsy specimens by hematoxylin and eosin staining. While gancylovir (GCV) was not used except in two patients, clinical outcomes including rates of remission and colectomy were not significantly different among the CMV reactivation-positive, -negative, and CMV IgG negative groups. Furthermore, CMV disappeared without GCV in most of the CMV reactivation-positive patients.CONCLUSIONS: CMV is frequently reactivated in active UC patients; however, it disappears without antiviral agents. Therefore, antiviral therapies should not be necessary for most UC patients with only CMV reactivation as long as CMV Ag values are low.


Inflammatory Bowel Diseases | 2004

Granulocytapheresis is useful as an alternative therapy in patients with steroid-refractory or -dependent ulcerative colitis

Makoto Naganuma; Shinsuke Funakoshi; Atsushi Sakuraba; Hanae Takagi; Nagamu Inoue; Haruhiko Ogata; Yasushi Iwao; Hiromasa Ishi; Toshifumi Hibi

Background:Recently, granulocyte and monocyte adsorption apheresis (GCAP) has been shown to be safe and effective for active ulcerative colitis (UC). We analyzed the safety and efficacy of GCAP (G-1 Adacolumn) in patients with steroid-refractory and -dependent UC. G-1 Adacolumn is filled with cellulose acetate carriers that selectively adsorb granulocytes and monocytes/macrophages. Methods:Forty-four patients with UC were treated with GCAP. These patients received 5 apheresis sessions over 4 weeks. Twenty patients had steroid-refractory UC (group 1) and 10 had steroid-dependent UC (group 2). Fourteen patients who did not want re-administration of steroids were treated with GCAP at the time of relapse, just after discontinuation of steroid therapy (group 3). Results:Of 44 patients treated with GCAP, 24 (55%) obtained remission (CAI ≤ 4), 9 (20%) showed a clinical response, and 11 (25%) remained unchanged. Only 2 of 10 patients (20%) with severe steroid-refractory UC (CAI ≥ 12) achieved remission, whereas 7 of 10 patients (70%) with moderate steroid-refractory UC achieved remission (p < 0.05). The dose of corticosteroids was tapered in 9 of 10 (90%) patients with steroid-dependent UC after GCAP therapy. Twelve (86%) of 14 patients in group 3 showed an improvement in symptoms and could avoid re-administration of steroids after GCAP. No severe adverse effects occurred. Conclusions:The findings of this study suggest that GCAP may be a useful alternative therapy for patients with moderate steroid-refractory or -dependent UC, although cyclosporin A or colectomy is necessary in patients with severe UC. GCAP may also be useful for avoiding re-administration of steroids at the time of relapse. Randomized, controlled clinical trials are needed to confirm these findings.


Bone Marrow Transplantation | 2000

Risk-adapted pre-emptive therapy for cytomegalovirus disease in patients undergoing allogeneic bone marrow transplantation.

Taisuke Mori; Shinichiro Okamoto; S. Matsuoka; Tomoharu Yajima; Masatoshi Wakui; Reiko Watanabe; Akaru Ishida; Yasushi Iwao; Makio Mukai; Toshifumi Hibi; Y. Ikeda

We prospectively evaluated a risk-adapted pre-emptive treatment with ganciclovir for CMV diseases in patients undergoing allogeneic bone marrow transplantation (BMT). High-level CMV antigenemia (10 or more positive cells on two slides) or CMV antigenemia at any level in patients with grade II–IV acute graft-versus-host disease (aGVHD) were chosen as risk factors. We also retrospectively evaluated virus reactivation in plasma using quantitative real-time polymerase chain reaction (PCR). Fifty patients were evaluable. None of the 27 patients with or without grade I aGVHD developed high-level CMV antigenemia or CMV disease. Among the 23 patients with grade II–IV aGVHD, 12 patients (52%) developed CMV antigenemia and were treated pre-emptively, of whom two developed CMV gastroenteritis or retinitis in spite of therapy. Six of the remaining 11 patients developed CMV gastroenteritis before CMV antigenemia was detectable. All of the eight patients with CMV diseases were successfully treated with ganciclovir and no deaths directly related to CMV disease occurred. In four of the seven evaluable patients with CMV gastroenteritis, real-time PCR was able to detect virus reactivation earlier than CMV antigenemia. Although our risk-adapted pre-emptive therapy effectively reduced CMV-related mortality, further refinements of this approach, particularly in the prevention of CMV gastroenteritis, may be achieved by incorporating real-time PCR. Bone Marrow Transplantation (2000) 25, 765–769.


Journal of Gastroenterology | 2007

Development of consensus statements for the diagnosis and management of intestinal Behçet's disease using a modified Delphi approach

Kenji Kobayashi; Fumiaki Ueno; Seiji Bito; Yasushi Iwao; Tsuneo Fukushima; Nobuo Hiwatashi; Masahiro Igarashi; Bun Ei Iizuka; Takahide Matsuda; Toshiyuki Matsui; Takayuki Matsumoto; Akira Sugita; Mitsuhiro Takeno; Toshifumi Hibi

BackgroundAlthough intestinal Behçets disease has been treated anecdotally with various therapeutic modalities, clinical evidence regarding management of intestinal Behçets disease is lacking. The objective of this study was to develop consensus-based practice guidelines for diagnosis and treatment of intestinal Behçets disease by using a modified Delphi approach.MethodsThree groups of Japanese gastroenterology specialists were involved in the study: moderators, an expert panel, and a professional group. Clinical statements for ratings were extracted from relevant literature, a survey of the professional group, and by discussion among the expert panel. The expert panel rated the clinical statements according to a nine point scale. After the first round of ratings, a panelist meeting was held to discuss areas of disagreement and to clarify areas of uncertainty. The list of clinical statements was revised after the panelist meeting, and a second round of rating was conducted.ResultsThirty-two relevant articles were selected in a literature search, and 35 clinical statements were extracted. An additional 209 clinical statements were developed from the survey and discussion among gastroenterology specialists. In the first and second rounds, 56% and 60% of statements, respectively, received median scores ≥7. The range of scores decreased considerably from the first to the second round.Conclusions5-Aminosalycylic acid, corticosteroids, immunosuppressants, enteral nutrition, total parenteral nutrition, and surgical therapy were considered standard therapy for intestinal Behçets disease. Infliximab, colchicines, thalidomide, other pharmacological therapy, endoscopic therapy, and leukocytapheresis were deemed experimental therapy. Based on a two-round modified Delphi approach, practice guidelines for diagnosis and treatment of intestinal Behçets disease were developed.


Journal of Gastroenterology | 2008

Reactivation of hepatitis B in a patient with Crohn’s disease treated using infliximab

Keisuke Ojiro; Makoto Naganuma; Hirotoshi Ebinuma; Hiroyoshi Kunimoto; Shinichiro Tada; Haruhiko Ogata; Yasushi Iwao; Hidetsugu Saito; Toshifumi Hibi

We encountered a case of reactivation of hepatitis B virus after administration of infliximab for Crohn’s disease. The use of infliximab was considered because the patient displayed abdominal symptoms and perianal lesions. Transaminases were normal, and hepatitis B virus (HBV) DNA was undetectable before treatment, so no antiviral treatment was used, and infliximab and low-dose 6-mercaptopurine were administered. This treatment was effective, but liver dysfunction and reactivation of HBV were observed after the fourth injection of infliximab. This is the first report of Crohn’s disease for which infliximab use was continued even after reactivation of HBV was observed. However, liver dysfunction was not improved by lamivudine. Antiviral treatment should be considered before administration of infliximab for patients with HBV.


European Journal of Gastroenterology & Hepatology | 2003

Dietary fat attenuates the benefits of an elemental diet in active Crohn's disease: a randomized, controlled trial.

Tadao Bamba; Takashi Shimoyama; Masaya Sasaki; Tomoyuki Tsujikawa; Yoshihiro Fukuda; Kazutaka Koganei; Toshifumi Hibi; Yasushi Iwao; Akihiro Munakata; Shinsaku Fukuda; Takayuki Matsumoto; Nobuhide Oshitani; Nobuo Hiwatashi; Tatsuo Oriuchi; Tetsuji Kitahora; Toshinori Utsunomiya; Yasushi Saitoh; Yasuo Suzuki; Mitsuyoshi Nakajima

Objectives Although an elemental diet has been established as the primary treatment for patients with Crohns disease, the influence of dietary fat on the elemental diet remains unclear. We have designed the first randomized, controlled trial for elemental diets containing different fat percentages in patients with active Crohns disease. Methods Each patient was randomized to receive one of three dose levels of fat in an elemental diet (Elental) for 4 weeks: 10 patients received low fat (3.06 g/day), 10 patients received medium fat (16.56 g/day) and eight patients received high fat (30.06 g/day). The additional fat was composed of long-chain fatty acids. All patients were evaluated using the International Organization of Inflammatory Bowel Disease rating, plus C-reactive protein level and erythrocyte sedimentation rate, which were measured at weekly intervals. Results Although the International Organization of Inflammatory Bowel Disease rating, C-reactive protein level and erythrocyte sedimentation rate in the low-fat group decreased, the values in the medium- and high-fat groups fluctuated during the study. The remission rate after 4 weeks in each group was 80%, 40% and 25% for patients in the low-, medium- and high-fat groups, respectively. Conclusions When the fat consisted of long-chain triglycerides, a high amount of this fat in the elemental diet formula decreased its therapeutic effect against active Crohns disease.


PLOS ONE | 2012

Novel, Objective, Multivariate Biomarkers Composed of Plasma Amino Acid Profiles for the Diagnosis and Assessment of Inflammatory Bowel Disease

Tadakazu Hisamatsu; Susumu Okamoto; Masaki Hashimoto; Takahiko Muramatsu; Ayatoshi Andou; Michihide Uo; Mina T. Kitazume; Katsuyoshi Matsuoka; Tomoharu Yajima; Nagamu Inoue; Takanori Kanai; Haruhiko Ogata; Yasushi Iwao; Minoru Yamakado; Ryosei Sakai; Nobukazu Ono; Toshihiko Ando; Manabu Suzuki; Toshifumi Hibi

Background Inflammatory bowel disease (IBD) is a chronic intestinal disorder that is associated with a limited number of clinical biomarkers. In order to facilitate the diagnosis of IBD and assess its disease activity, we investigated the potential of novel multivariate indexes using statistical modeling of plasma amino acid concentrations (aminogram). Methodology and Principal Findings We measured fasting plasma aminograms in 387 IBD patients (Crohns disease (CD), n = 165; ulcerative colitis (UC), n = 222) and 210 healthy controls. Based on Fisher linear classifiers, multivariate indexes were developed from the aminogram in discovery samples (CD, n = 102; UC, n = 102; age and sex-matched healthy controls, n = 102) and internally validated. The indexes were used to discriminate between CD or UC patients and healthy controls, as well as between patients with active disease and those in remission. We assessed index performances using the area under the curve of the receiver operating characteristic (ROC AUC). We observed significant alterations to the plasma aminogram, including histidine and tryptophan. The multivariate indexes established from plasma aminograms were able to distinguish CD or UC patients from healthy controls with ROC AUCs of 0.940 (95% confidence interval (CI): 0.898–0.983) and 0.894 (95%CI: 0.853–0.935), respectively in validation samples (CD, n = 63; UC, n = 120; healthy controls, n = 108). In addition, other indexes appeared to be a measure of disease activity. These indexes distinguished active CD or UC patients from each remission patients with ROC AUCs of 0.894 (95%CI: 0.853–0.935) and 0.849 (95%CI: 0.770–0.928), and correlated with clinical disease activity indexes for CD (rs = 0.592, 95%CI: 0.385–0.742, p<0.001) or UC (rs = 0.598, 95%CI: 0.452–0.713, p<0.001), respectively. Conclusions and Significance In this study, we demonstrated that established multivariate indexes composed of plasma amino acid profiles can serve as novel, non-invasive, objective biomarkers for the diagnosis and monitoring of IBD, providing us with new insights into the pathophysiology of the disease.


Inflammatory Bowel Diseases | 2008

Efficacy of infliximab for induction and maintenance of remission in intestinal Behçet's disease

Makoto Naganuma; Atsushi Sakuraba; Tadakazu Hisamatsu; Hiroki Ochiai; Hirotoshi Hasegawa; Haruhiko Ogata; Yasushi Iwao; Toshifumi Hibi

Background: Intestinal Behçet disease (BD) is characterized by intestinal inflammation with round and oval ulcers associated with gastrointestinal symptoms. Although several cases have been reported that infliximab is effective for induction of remission, the efficacy of infliximab for maintaining remission is unknown. Methods: Six cases with fulminant intestinal BD were treated with infliximab. All patients were steroid‐dependent and refractory to immunosuppressants; 3 patients were treated with 6‐mercaptopurine, 1 patient with azathioprine, 1 patient with cyclosporine A, and 1 patient with methotrexate. Results: Four patients achieved remission by infliximab and all of these patients maintained remission with scheduled treatments of infliximab, with the longest duration of remission being about 3 years. Another 2 patients with ileal ulceration required surgery; however, 1 patient has maintained remission by scheduled treatment of infliximab for 2 years after surgery. Conclusions: Infliximab appears to offer an option for fulminant intestinal BD to induce and maintain remission, although a randomized control trial is needed.


Inflammatory Bowel Diseases | 2001

Measurement of colonic mucosal concentrations of 5-aminosalicylic acid is useful for estimating its therapeutic efficacy in distal ulcerative colitis: comparison of orally administered mesalamine and sulfasalazine.

Makoto Naganuma; Yasushi Iwao; Haruhiko Ogata; Nagamu Inoue; Shinsuke Funakoshi; Shojirou Yamamoto; Yuji Nakamura; Hiromasa Ishii; Toshifumi Hibi

ObjectivesOral 5-aminosalicylic acid (5-ASA) preparations have been used frequently in the treatment of ulcerative colitis. However, there have been few reports investigating the relationship between colonic mucosal concentrations of 5-ASA and its clinical efficacy when oral sulfasalazine or 5-ASA compounds were administered. The aim of this study is to compare the mucosal concentrations of 5-ASA ensured by sulfasalazine or mesalamine, and to define the clinical significance of the measurement of 5-ASA concentrations in the treatment of distal ulcerative colitis. Materials and MethodsBiopsies were taken from the rectum and sigmoid colon of the oral sulfasalazine group (n = 13) and the slow-release 5-ASA (mesalamine) group with (n = 5) or without (n = 11) rectal administration of 5-ASA. High-pressure liquid chromatography was used to measure the tissue concentrations of 5-ASA and its metabolites. We compared the 5-ASA concentrations of the sulfasalazine group with the mesalamine group. Furthermore, we analyzed the relationship between tissue 5-ASA concentrations and the Disease Activity Index (DAI). ResultsThe concentrations of 5-ASA and acetyl-5-ASA in the sulfasalazine group were higher than those in the group taking oral mesalamine alone (p < 0.01). The concentration of 5-ASA was much higher in the patients who received oral and rectal mesalamine in an enema than in the patients who had oral mesalamine alone. There was a significant inverse correlation between the DAI and concentrations of 5-ASA in the rectum (r = 0.712, p < 0.001). ConclusionsWe demonstrated that the colonic mucosal concentration of 5-ASA was significantly higher in the sulfasalazine group than in the mesalamine group. Furthermore, the concentrations of mucosal 5-ASA may be a good marker for the estimation of its efficacy in the treatment of ulcerative colitis.

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Katsuyoshi Matsuoka

Tokyo Medical and Dental University

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