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  • Articles: DFG German National Licenses  (4)
  • Ito cell  (2)
  • Immunoelectron microscopy  (1)
  • Key words Biliary epithelial cells  (1)
  • 1
    ISSN: 1432-2307
    Keywords: Adult human liver ; Ito cell ; Myofibroblast ; Immunocytochemistry ; α-Smooth muscle actin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To identify Ito cells in normal and pathological adult human livers, immunohistochemical studies were performed by the avidin-biotin-peroxidase complex method using monoclonal antibodies for α-smooth muscle actin (ASMA), desmin, and vimentin. Fifty one needle biopsies, 7 surgically resected specimens, and 5 autopsy specimens were studied. In the normal adult liver vascular smooth muscle cells and pericytes, together with perisinusoidal cells with thin cytoplasmic processes were positive for ASMA. These latter cells formed a loose and discontinuous layer along the sinusoidal walls. Immunoelectron microscopy showed that the ASMA-positive perisinusoidal cells were Ito cells containing fat droplets. The other sinusoidal lining cells were negative for ASMA. In chronic liver disease, ASMA-positive Ito cells showed an increase in number, size, and the intensity of immunostaining in areas of piecemeal necrosis), and formed a continuous cellular network. These cells were dendritic in shape with irregularly elongated cytoplasmic processes and contained an increased amount of microfilaments, in association with loss of the characteristic fat droplets. Thus, their ultrastructural features corresponded to those of myofibroblastic cells. Ito cells showed no staining for desmin in both normal and pathological livers. These results indicate that immunohistochemistry using an anti-ASMA antibody is a sensitive and reliable method for the identification of both normal and transformed Ito cells in adult human livers.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2307
    Keywords: Natural killer cells ; Pit cells ; Large granular lymphocytes ; Immunoelectron microscopy ; Leu-7
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the liver biopsies of 78 patients with hepatitis virus-related chronic liver diseases (B type; 14 patients, C type; 64 patients) by immunoelectron microscopy with the Leu-7 monoclonal antibody in order to determine the association of NK/K cells in virus-related chronic liver diseases. Most Leu-7 positive cells in the liver had the Pit cell morphology but a few Pit cells were Leu-7 negative. A few Leu-7 positive cells had neither Pit cell nor typical T cell morphology. No ultrastructural difference was observed in Leu-7 positive cells between hepatitis B virus- and hepatitis C virus-related chronic liver diseases. Regardless of virus type and hepatitis activity, the fine morphology of extravascular Leu-7 positive cells differed considerably from intravascular cells. Leu-7 positive cells were regularly seen in the cellular infiltrates but the ratio of Leu-7 positive cells/whole infiltrates was low. There was no correlation between the inflammatory activity of the disease and the level of Leu-7 positive cell infiltration. A virus aetiology (hepatitis-C or hepatitis-B) did not affect Leu-7 positive cell infiltration. We conclude that NK cells play only a small role in the pathogenesis of hepatitis B virus or hepatitis C virus-related hepatocytolysis, during the chronic stage.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2307
    Keywords: Ito cell ; Fulminant hepatitis ; Postnecrotic fibrosis ; α-Smooth muscle actin ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To examine the relationship of Ito cells to postnecrotic liver fibrosis, liver specimens, obtained at autopsy from 17 patients with acute massive necrosis (AMN) and acute submassive hepatic necrosis (ASMN), were examined immunohistochemically. In normal adult livers, Ito cells positive for α-smooth muscle actin isoform (ASMA) were rarely seen, scattered along hepatic sinusoids. In contrast, in AMN the Ito cells in necrotic areas became strongly positive for ASMA. They were swollen with elongated cytoplasmic processes along collapsed sinusoidal walls. Around these ASMA-positive Ito cells, there were numerous infiltrated macrophages and lymphocytes present. There was no significant alteration of fibroblasts in the portal tracts. In the middle and late stages of ASMN, the spindle-shaped ASMA-positive Ito cells formed a continuous cellular network. New fibre formation was predominantly around them. In this immediate postnecrotic fibrosis, ASMA-positive stromal cells of Ito cell origin were distributed irregularly and were closely associated with reticulin and newly-formed collagen fibres. Regenerative nodules were surrounded by dense layers of ASMA-positive stromal cells. Throughout the stages of ASMN, portal fibroblasts remained negative for ASMA. We believe that Ito cells in necrotic areas show myofibroblastic transformation and play a central role in the postnecrotic liver fibrosis. Portal fibroblasts play no significant part in this type of fibrosis.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2277
    Keywords: Key words Biliary epithelial cells ; TGF-β1 rat ; Mixed lymphocyte reaction ; CTL
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immune response to liver allografts may be different from that to other organ transplants since immunological manipulation easily attenuates immune-response to liver allografts. Numerous studies on the alloantigen-specific immune response have been carried out, however, the precise mechanisms involved in this attenuation are not clear yet. Here we suggest the attenuation of alloantigen-specific immune response by TGF-β1 derived from biliary epithelial cells. The transforming growth factor-β1 (TGF-β1) expression in rat liver was examined immunohistologically. Rat biliary epithelial cells (BEC) were purified from the perfused liver and added to allogeneic mixed lymphocyte reaction (allo-MLR) to assess their attenuating potential on allo-MLR and alloantigen-specific cytotoxic T lymphocyte (allo-CTL) induction. Immunohistological investigation revealed the expression of TGF-β1 in biliary epithelial cells. Both purified biliary epithelial cells and TGF-β1 attenuated allo-MLR and allo-CTL induction in a dose-dependent manner, and anti-TGF-β1 antibody partially relieved this attenuation. This study reveals that biliary epithelial cells, the major target cells of allo-antigen specific immune response, contain TGF-β1 and that they have a capacity to attenuate allo-MLR and allo-CTL induction.
    Type of Medium: Electronic Resource
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