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Publications (5)43.71 Total impact

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    ABSTRACT: Few models have described a chronic food allergy with morphological changes in the intestinal mucosa. Here we established an ovalbumin (OVA)-induced, cell-mediated, allergic rat model and examined lymphocyte migration in the gut. Brown Norway rats were intraperitoneally sensitized to OVA and then given 10 mg OVA/day by gastric intubation for 6 wk. Lymphocyte subsets and adhesion molecules were examined immunohistochemically, and the migration of T lymphocytes to microvessels of Peyer's patches and villus mucosa was observed by using an intravital microscope. Serum OVA-specific IgG and IgE levels were increased in animals repeatedly exposed to OVA. Significant villus atrophy and increased crypt depth was accompanied by increased infiltration of T lymphocytes in the small intestinal mucosa of the group given OVA. Expression of rat mast cell protease II and of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) was also increased in these groups. The administration of anti-MAdCAM-1 antibody significantly attenuated the OVA-induced changes in the mucosal architecture and in CD4 T lymphocyte infiltration. Intravital observation demonstrated that in rats with a chronic allergy, T lymphocytes significantly accumulated in villus microvessels as well as in Peyer's patches via a MAdCAM-1-dependent process. Our model of chronic food allergy revealed that lymphocyte migration was increased with MAdCAM-1 upregulation.
    AJP Gastrointestinal and Liver Physiology 06/2004; 286(5):G702-10. DOI:10.1152/ajpgi.00183.2003 · 3.80 Impact Factor
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    ABSTRACT: Alterations in immunological defense in the gut may lead to the bacterial infection that is frequently associated with cirrhosis of the liver. The aim of this study was to investigate the changes in distribution and function of intestinal intraepithelial lymphocytes (IELs) in relation to intestinal barrier dysfunction in experimental cirrhosis. Cirrhosis was induced in mice by treatment with carbon tetrachloride (CCl4) intraperitoneally with 5% alcohol in drinking water for 12 weeks. Bacterial translocation was assessed in mesenteric lymph nodes (MLNs) by the transport of fluorescence-labeled latex beads and by bacteriological cultures. The lymphocyte subpopulation was compared in three groups (cirrhosis, alcohol alone and controls). IFN-gamma production from isolated IELs was determined by ELISA after stimulation with anti-CD3 or IL-12/IL-18. The total number of IELs significantly increased in the cirrhosis and alcohol groups. There was a preferential increase in TCRgammadelta+CD8+ population in the alcohol group, but no change in cirrhosis. Bacterial translocation was negative in the control group, and a small number was noted in the alcohol group, whereas it was significantly noted in the cirrhosis group. Although the number of IEL was significantly increased in the cirrhosis group, their proliferative response was decreased, and IFN-gamma production from each IEL was markedly diminished in either stimulation by anti-CD3 or IL-12/IL-18. These changes were more remarkable in the cirrhosis group than in the alcohol group. In conclusion, bacterial translocation due to intestinal barrier dysfunction in cirrhosis may be closely correlated with the alteration of the immune function in IELs.
    Immunology Letters 12/2003; 90(1):3-11. DOI:10.1016/j.imlet.2003.05.002 · 2.51 Impact Factor
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    ABSTRACT: Ceramides have emerged as key participants in the signaling pathway of cytokines and apoptosis. We previously revealed that phorbol 12-myristate 13-acetate (PMA) induced experimental ulcers in rat gastric mucosa. In this study, we investigated the role of ceramide in ulcer formation and its relation to the activation of transcription factors and apoptosis. PMA was subserosally injected to rat glandular stomach. Fumonisin B1 (FB1), an inhibitor of ceramide synthase, was administered together with the PMA. The time course of ceramide content was quantified using thin layer chromatography and the number of apoptotic cells was determined by immunohistochemistry. The activation of transcription factor nuclear factor-kappaB (NF-kappaB) or activator protein-1 (AP-1) was evaluated using an electrophoretic mobility shift assay. The administration of FB1 attenuated PMA-induced gastric ulcer formation in a dose-dependent manner. Before the ulcers became obvious, the ceramide content (C18 and C24 ceramide) increased significantly in the gastric wall. The activation of NF-kappaB and AP-1 and an increase in the number of apoptotic cells were also observed. Both of these were significantly inhibited by the coadministration of FB1. However, NF-kappaB inhibitors attenuated gastric ulcer formation without affecting the ceramide content or the number of apoptotic cells. Ceramide formation in the stomach significantly contributes to PMA-induced tissue damage, possibly via the activation of transcription factors and an increase in apoptosis in the gastric mucosa. However, after the increase in ceramide levels, the NF-kappaB and apoptosis pathways may be separately involved in ulcer formation.
    Journal of Pharmacology and Experimental Therapeutics 05/2003; 305(1):232-9. DOI:10.1124/jpet.102.045195 · 3.97 Impact Factor
  • Gastroenterology 04/2003; 124(4). DOI:10.1016/S0016-5085(03)82466-6 · 16.72 Impact Factor
  • Gastroenterology 04/2003; 124(4). DOI:10.1016/S0016-5085(03)80761-8 · 16.72 Impact Factor