Browsing by Subject "Appendix"

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    Histochemical study of expression of lectin-reactive carbohydrate epitopes and glycoligand-binding sites in normal human appendix vermiformis, colonic mucosa, acute appendicitis and colonic adenoma
    (Murcia : F. Hernández, 1996) Brinck, U.; Bosbach, R.; Korabiowska, M.; Schauer, A.; Gabius, H.J.
    In a glycohistochemical analysis of human appendix vermiformis we report the assessment of lectin binding in cells of the Gut Associated Lymphoid Tissue of normal samples and in acute appendicitis using a panel of plant, invertebrate and mammalian lectins with specificity for a-L-Fuc (UEA-I), a-D-Gluc and a-DMan (Con A), a-D-GalNAc (DBA), GalNAc (SBA, HPA), B-Gal (RCA-I, 14 kDa=galectin-l) and a-, B-Gal (VAA). Moreover, we initiate the study of expression of carbohydrate-binding sites in this tissue and in colonic mucosa, employing several types of carrier-immobilized carbohydrate ligands as suitable probes for this purpose. Within the three populations of macrophages intralsubepithelial macrophages of the dome region, the lamina propria of the intercryptal region and the follicleassociated epithelium were apparently reactive with most of the lectins and also with mannose and fucose residues of the tested neoglycoproteins. Distinguishing features of germinal center macrophages in relation to intra-/subepithelia1 phagocytes were the lack of binding of UEA-I and DBA. In comparison to all other types of phagocytes, macrophages of the T-region displayed a rather restricted binding capacity only to Con A and RCA-I. Labeling of macrophages with SBA, HPA and VAA in this location was only rarely found. With respect to dendritic cells no consistently positive reaction was seen for follicular cells, whereas interdigitating cells of the T-region bound Con A, HPA and RCA-I, and, less frequently, SBA. Lymphocytes in all anatomical subsites of the Gut Associated Lymphoid Tissue, centrocytes, centroblasts and plasma cells had binding sites for Con A and RCA-I in common. Notably, a small number of lymphocytes mostly in the T-region but also in B-cell-rich areas expressed intranuclear binding sites for fucose and mannose residues. Intraepithelial lymphocytes and lymphatic cells of the T-region differed from lymphocytes in other regions by a more frequent expression of VAA-binding sites. The epithelium of appendix vermiformis and colonic mucosa not only presents lectin binding sites, but also has the capacity to bind carbohydrate structures, as shown by labeled glycoligand-exposing neoglycoproteins. In normal mucosa the extent of binding appeared to be associated with maturation of cells, the surface epithelium showing the most intense staining reaction. This pattern is not detectable in colonic adenoma which reveal increased intensity, when compared to normal mucosa. In contrast to development of hyperplasia, acute inflammation in appendicitis caused no detectable changes of neoglycoprotein binding. Taking our previous assessment on lectin binding in appendicitis into account, we conclude that glycosylation of goblet cell mucus, but not the capacity to bind certain sugar epitopes responds to inflammatory processes, whereas tumorigenesis of colonic adenoma can also affect the binding of neoglycoproteins.
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    Lectin-binding sites in the epithelium of normal
    (Murcia : F. Hernández, 1995) Brinck, U.; Bosbach, R.; Korabiowska, M.; Schauer, A.; Gabius, H.J.
    By using histochemical methods, the binding pattern of various lectins in the epithelium of normal human appendix vermiformis was assessed. In addition to plant and invertebrate sugar receptors with nominal monosaccharide specificity for a-L-Fuc (UEA-1), a-DMan and a-D-Gluc (Con A), a-D-GalNAc (DBA), DGalNAc (SBA, HPA) B-D-Gal (RCA-I) and D-Gal (VAA), a mammalian B-galactoside-specific lectin (MW, 14 kDa) was included in the applied panel. The apical surface of enterocytes presented binding sites for RCA-1 on al1 cells, binding sites of UEA-1, DBA, SBA, HPA and VAA heterogeneously and no binding sites of Con A and 14 kDa. Binding sites of DBA, SBA, HPA, VAA and RCA-1 within enterocytes were located primarily focally in a supranuclear position, whereas Con A and 14 kDa bound to the cytoplasm both in apical and basa1 cell parts. In the follicle-associated epithelium more enterocytes expressed SBA- and VAA-binding sites than in the crypt epithelium. No differences between the lectin-binding pattern of M-cells and enterocytes were found in the follicle-associated epithelium. Intraepithelial macrophages were heterogeneously positive for the full panel of applied lectins. In contrast, intraepithelial lymphatic cells expressed binding sites only for RCA-1 and less prominently for Con A, VAA and 14 kDa. Goblet cell mucus contained lectin-binding sites in a heterogeneous manner: binding sites for Con A were not detected in goblet cells for DBA, SBA, VAA and 14 kDa in less than 20%, for UEA-1 in 20-40%, for HPA in 40-60% and for RCA-1 in 60-100% of the goblet cells. Secreted mucus differed in its lectin-binding capacity from intracellular goblet cell mucus selectively by an increase of UEA-1, SBA- and RCA-1-binding sites and a lack of 14 kDa-binding sites. Comparative study of lectin binding to goblet cell mucin in another region of the large intestine, namely the rectosigmoid, demonstrated that DBA, SBA and 14 kDa bound mainly to the dista1 colon, while UEA-1 and VAA labelling was selectively found in Oífprint reguests lo: Dr. Ulrich Brinck, M.D., Department of Pathology, University of Gottingen, Robert-Koch-Str. 40, D-37075 Gottingen, Germany apendiceal goblet cell mucin. Comparing the lectin-binding pattern in normal appendix epithelium and in appendicitis, the percentage of goblet cells expressing DBA- and SBA-binding sites in mucus globules was found to be about 4 times higher in appendicitis than in normal appendix. These results demonstrate that the expression of lectin-binding sites in appendiceal goblet mucin is specifically altered in appendicitis, indicating that there are selective changes of glycosylation of mucin in goblet cells mainly of the lower and middle crypt segment. Changes of lectinbinding pattern in appendicitis are discussed in connection with histochernical findings in inflammatory bowel disease.