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Dive into the research topics where Atsushi Toyonaga is active.

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Featured researches published by Atsushi Toyonaga.


Clinical and Experimental Immunology | 2008

IL-8 as an important chemoattractant for neutrophils in ulcerative colitis and Crohn's disease.

Keiichi Mitsuyama; Atsushi Toyonaga; Ei Sasaki; K. Watanabe; Hideo Tateishi; T. Nishiyama; T. Saiki; Hideo Ikeda; Osamu Tsuruta; Kyuichi Tanikawa

IL‐8 is generating increasing interest as a powerful neutrophil chemoattractant and activator. To elucidate the mechanisms of neutrophil infiltration in inflammatory bowel disease, we examined 33 patients with ulcerative colitis (UC),18 with Crohns disease (CD), eight with some other type of colitis, and 18 normal control subjects for measurement of IL‐8 in homogenates of colonic biopsy specimens. The affected colonic mucosa was found lo contain significantly more IL‐8 in patients with active inflammatory bowel disease than in patients with inactive disease (UC, P<0.001: CD, P<0.001), in patients with other types of colitis (UC, P<0.05; CD, P<0.01), or in normal control subjects (UC. P<0.001; CD. P<0.001). Colonic IL‐8 levels correlated significantly with the macroscopic grade of local inflammation, especially in patients with UC (P< 0.001). Colonic lL‐8 levels also correlated well with the neutrophil numbers in mucosal tissue (UC, r = 0.950, P<0.001; CD. r=0‐940, P<0.001), and with colonic IL‐1β (r=0.911, P<0.001) and tumour necrosis factor‐alpha (TNF‐a) levels (r=0‐604. P < 0001) in patients with these two conditions. These data suggest a potential role for IL‐8 and its regulatory cytokines IL‐I and TNF‐a in mediating neutrophil infiltration of the gut wall in inflammatory bowel disease.


World Journal of Surgery | 2001

Optimum Treatment Strategy for Superficial Esophageal Cancer: Endoscopic Mucosal Resection versus Radical Esophagectomy

Hiromasa Fujita; Susumu Sueyoshi; Hideaki Yamana; Koji Shinozaki; Uhi Toh; Yuichi Tanaka; Takashi Mine; Masahiro Kubota; Atsushi Toyonaga; Hiroshi Harada; Sigeki Ban; Masahide Watanabe; Yukihiko Toda; Emi Tabuchi; Naofumi Hayabuchi; Hiroki Inutsuka

This study was designed to determine the optimum treatment for a superficial esophageal cancer involving the mucosal or submucosal layer of the esophagus. The subjects were 150 patients with a superficial esophageal cancer who underwent endoscopic mucosal resection (EMR) or esophagectomy in Kurume University Hospital from 1981 to 1997. The mortality and morbidity rates, survival rate, and recurrence rate were retrospectively compared for (1) 35 patients who underwent EMR and 37 patients who underwent esophagectomy for a mucosal esophageal cancer and (2) 45 patients who underwent extended radical esophagectomy and 33 patients who underwent less radical esophagectomy for a submucosal esophageal cancer. Among the 72 patients with a mucosal cancer, lymph node metastasis/recurrence was observed in only one (1%); whereas of 78 patients with a submucosal cancer it was observed in 30 (38%). Among patients with a mucosal cancer the mortality and morbidity rates after EMR were lower than for those after esophagectomy. The survival rate after EMR was the same as that after esophagectomy. No recurrence was observed after either treatment modality. Among the patients with a submucosal cancer, the survival rate was higher and the recurrence rate lower after extended radical esophagectomy; than after less radical esophagectomy; the mortality and morbidity rates after extended radical esophagectomy were the same as those after less radical esophagectomy. Multivariate analysis demonstrated that the treatment modality (EMR versus esophagectomy) did not influence the survival of patients with a mucosal esophageal cancer, whereas it strongly influenced the survival of patients with a submucosal esophageal cancer. We concluded that EMR was the mainstay of treatment for a mucosal esophageal cancer, and extended radical esophagectomy was the mainstay of treatment for a submucosal esophageal cancer.


Gut | 1995

Soluble interleukin-6 receptors in inflammatory bowel disease: relation to circulating interleukin-6.

Keiichi Mitsuyama; Atsushi Toyonaga; E Sasaki; O Ishida; H Ikeda; Osamu Tsuruta; K Harada; H Tateishi; T Nishiyama; K Tanikawa

The in vivo appearance of soluble interleukin (IL)-6 receptor (sIL-6R) in serum from patients with inflammatory bowel disease was examined using an enzyme linked immunosorbent assay (ELISA). The serum sIL-6R concentrations in patients with active disease (ulcerative colitis, 148.4 (5.1); Crohns disease, 142.3 (9.3) ng/ml; mean (SEM)) were significantly raised compared with those in patients with inactive disease (ulcerative colitis, 116.2 (7.2); Crohns disease, 114.3 (7.1) ng/ml), some other type of colitis (104.8 (11.6) ng/ml), or in normal subjects (107.3 (2.4) ng/ml). These differences were also seen in paired samples examined during both active and inactive phases. Additionally, serum sIL-6R and IL-6 concentrations correlated significantly with C-reactive protein levels in both ulcerative colitis and Crohns disease patients (r = 0.23 and 0.56, respectively; p < 0.05 for both). Furthermore, gel filtration analysis of serum from these patients showed two major peaks of immunoreactive IL-6-one peak corresponding to free IL-6 and another peak to sIL-6R-bound IL-6-this was further confirmed by a luminescence sandwich ELISA. These results, together with its in vitro effects, indicate that natural sIL-6R may function as a powerful enhancer of the IL-6-dependent immune processes observed in inflammatory bowel disease.


Scandinavian Journal of Infectious Diseases | 1999

Helicobacter pylori in the Natural Environment

Kanae Sasaki; Yoshito Tajiri; Michio Sata; Yasuhiro Fujii; Futoshi Matsubara; Mangen Zhao; Seiichi Shimizu; Atsushi Toyonaga; Kyuichi Tanikawa

The presence of Helicobacter pylori (H. pylori) in the natural environment has been demonstrated in a number of studies. However, its route of infection into humans is unknown. To study this further, we attempted to detect H. pylori in the natural environment in a region of Japan with a high infection rate. Tap and well water and field soil samples were collected from around the residences of subjects who had participated in an epidemiological survey in 1996. Samples of water from rivers and ponds, and specimens of flies and cow faeces were collected in the region. DNA was extracted from the water, field soil and faecal samples after selective collection of H. pylori by the immunomagnetic-bead separation technique. H. pylori-specific DNA was detected in water, field soil, flies and cow faeces by nested polymerase chain reaction (PCR), and the ureA partial sequences of the PCR products were aligned. The nucleotide sequences of the samples amplified by PCR were highly homologous (96-100%) with the H. pylori sequence in the GenBank database and the H. pylori-specific DNA sequences were highly homologous with each other. These findings suggest the existence of H. pylori in the natural environment and a possible transmission route.


Gut | 2006

STAT3 activation via interleukin 6 trans-signalling contributes to ileitis in SAMP1/Yit mice

Keiichi Mitsuyama; Satoshi Matsumoto; Stefan Rose-John; Asuka Suzuki; Taeko Hara; Nobuo Tomiyasu; Kazuyo Handa; Osamu Tsuruta; Hideyuki Funabashi; Jürgen Scheller; Atsushi Toyonaga; Michio Sata

Background and aim: SAMP1/Yit mice spontaneously develops intestinal inflammation. Previously, we demonstrated that the signal transducer and activator of transcription (STAT)-3/suppressor of cytokine signalling (SOCS)-3 pathway is pivotal in human inflammatory bowel disease. In our studies in SAMP1/Yit mice, the aim was to investigate whether STAT3 activation contributes to ileitis and to examine the therapeutic effects of this signal blockade. Methods: Intestinal expression of phospho-STAT3 in SAMP1/Yit mice and control AKR/J mice was examined by western blotting and immunohistochemistry. SOCS3 and interleukin 6 (IL-6) mRNA were determined by northern blotting and reverse transcription-polymerase chain reaction, respectively. We also examined the effects of intravenously injected hyper-IL-6, an IL-6/soluble IL-6 receptor fusion protein, and of soluble gp130-Fc, a specific inhibitor of soluble IL-6 receptor signalling, on STAT3 phosphorylation and disease severity in SAMP1/Yit mice. Results: Phospho-STAT3 was expressed strongly during the disease course in SAMP1/Yit mice but only transiently in AKR/J mice. Phospho-STAT3 was localised to epithelial and mononuclear cells in the diseased intestine of SAMP1/Yit mice. SOCS3 as well as IL-6 mRNAs were expressed in affected intestine. Administration of hyper-IL-6 caused disease exacerbation and enhancement of STAT3 phosphorylation. In contrast, soluble gp130-Fc administration ameliorated the disease and suppressed STAT3 phosphorylation. Conclusion: STAT3 signalling is critical in the development of intestinal inflammation in SAMP1/Yit mice. Blockade of this signalling pathway by soluble gp130-Fc may have therapeutic effects in inflammatory bowel disease.


Digestion | 1991

Colonic Mucosal Interleukin-6 in Inflammatory Bowel Disease

Keiichi Mitsuyama; Ei Sasaki; Atsushi Toyonaga; Hideo Ikeda; Osamu Tsuruta; Akira Irie; Nobuyuki Arima; Tetsuharu Oriishi; Kazunori Harada; Kazuhiro Fujisaki; Michio Sata; Kyuichi Tanikawa

Interleukin-6, a cytokine produced by various cell types, has a major role in inflammatory and immunological reactions. To define its potential role in inflammatory bowel disease, its concentrations in endoscopic biopsy samples from patients with ulcerative colitis and Crohns disease were measured. The involved colonic mucosa from active disease was found to contain significantly larger amounts of interleukin-6 than that from inactive disease or normal controls. Colonic mucosal interleukin-6 levels correlated well with the grade of macroscopic inflammation, especially in patients with ulcerative colitis. The levels of interleukin-6 decreased in parallel with clinical improvement following the start of therapy in patients with both forms of inflammatory bowel disease. Mucosal interleukin-6 is thus concluded to accurately reflect the degree of colonic inflammation and may be importantly associated with inflammatory and immunological phenomena seen in inflammatory bowel disease.


Journal of Gastroenterology | 2003

Germinated barley foodstuff, a prebiotic product, ameliorates inflammation of colitis through modulation of the enteric environment

Osamu Kanauchi; Isao Serizawa; Yoshio Araki; Asuka Suzuki; Akira Andoh; Yoshihide Fujiyama; Keiichi Mitsuyama; Kosuke Takaki; Atsushi Toyonaga; Michio Sata; Tadao Bamba

Background: Germinated barley foodstuff (GBF), which contains glutamine-rich protein and hemicellulose-rich fiber, exhibits therapeutic effects in ulcerative colitis; however, its mechanism is still under investigation. The aim of this study was to evaluate the anti-inflammatory effects of GBF on colitis in terms of the epithelial inflammatory response. Methods: Mice with dextran sulfate sodium-induced colitis were used. The effects of GBF on the colitis were evaluated by measuring the body weight; disease activity; mucosal damage (histology, mucosal inflammatory parameters, nuclear factor kappa B [NFkB] activation, and signal transducer and activator of transcription 3 [STAT3]); serum interleukin 6 (IL-6) level; cecal short-chain fatty acids (SCFAs); and bile acid contents. Results: GBF significantly prevented disease activity and body weight loss after induction of colitis. Serum IL-6 level and mucosal STAT3 expression were also significantly attenuated, with a conspicuous reduction of mucosal damage; NFkB activity showed the same tendency. Cecal butyrate content was significantly higher and, interestingly, GBF mice had lower bile acid concentrations than the control group. Conclusions: GBF has the potential to reduce the epithelial inflammatory response by depressing STAT-3 expression and inhibiting NFkB binding activity. These effects may be brought about by an increase of butyrate production and adsorption of bile acids.


Scandinavian Journal of Gastroenterology | 1998

Detection of Pro- and Anti-Inflammatory Cytokines in Stools of Patients with Inflammatory Bowel Disease

T. Saiki; Keiichi Mitsuyama; Atsushi Toyonaga; H. Ishida; Kyuichi Tanikawa

BACKGROUND Cytokines play a predominant role in immune and inflammatory reactions in inflammatory bowel disease. Any cytokine that is produced locally as a result of gut inflammation may leak into the bowel lumen and appear in the stools. We examined the usefulness of determining cytokine profiles in the stools of patients with ulcerative colitis or Crohns disease. METHODS Cytokine concentrations in stool extracts were measured in 36 patients with ulcerative colitis, 32 patients with Crohns disease, 9 controls with inflammatory disease, and 18 normal controls by means of enzyme-linked immunosorbent assays. RESULTS Stool concentrations of interleukin-1beta and interleukin-1 receptor antagonist in patients with active inflammatory bowel disease increased significantly and correlated with various inflammatory factors and stool concentrations of polymorphonuclear cell elastase. The ratio of interleukin-1 receptor antagonist to interleukin-1beta in active disease was reduced significantly compared with that in inactive disease or in normal controls. Paired analysis showed a decrease in tumor necrosis factor-alpha and interleukin-1beta and interleukin-1 receptor antagonist and an increase in interleukin-4 and interleukin-10 concentrations after the resolution of disease exacerbation. CONCLUSIONS Measurement of cytokines in stools may be a useful and noninvasive means of understanding pathophysiology and clinical monitoring in inflammatory bowel disease.


Scandinavian Journal of Gastroenterology | 1998

Role of interleukin-10 in a murine model of dextran sulfate sodium-induced colitis

M. Tomoyose; Keiichi Mitsuyama; H. Ishida; Atsushi Toyonaga; Kyuichi Tanikawa

Background: Increased production of proinflammatory cytokines is characteristic of both animal models of experimental colitis and human inflammatory bowel disease. This study was designed to characterize the functional role of interleukin (IL)-10 in a murine model of experimental colitis. Methods: Cytokine profiles were analyzed in animals with dextran sulfate sodium-induced colitis. The effect of treatment with IL-10 or anti-IL-10 antibodies on colonic cytokine production in vitro and tissue damage in vivo were evaluated. Results


Journal of Gastroenterology and Hepatology | 2003

Balloon-occluded retrograde transvenous obliteration improves liver function in patients with cirrhosis and portal hypertension

Yasunao Miyamoto; Kazuhiko Oho; Masafumi Kumamoto; Atsushi Toyonaga; Michio Sata

Background and Aim:  Balloon‐occluded retrograde transvenous obliteration (B‐RTO) is a novel therapeutic method for the treatment of large gastric fundal varices with spontaneous splenorenal shunt (SRS). However, the effects of B‐RTO on liver function remain unknown.

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