Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The oligosaccharides of the mucus glycoproteins of the human rectum are important for the lubricant and protective role suggested for the rectal mucus. Changes in oligosaccharide composition are observed in several colon diseases, and some of these changes could be used as diagnostic and prognostic indicators. Thus, a previous knowledge of the normal mucus glycoproteins is necessary. The aim of the present study is the characterization of the oligosaccharides of the goblet cells and enterocytes of the human rectum. For this, a battery of 15 lectins, in combination with chemical and enzymatic deglycosylation procedures, was used. Our results suggest the presence of N-acetylglucosamine (GlcNAc), Man, Glc, N-acetylneuraminic acid (Neu5Ac)(alpha2-6)- and Neu5Ac(alpha2-3)-linked, N-acetylgalactosamine (GalNAc) and Gal(beta1-3)GalNAc in the oligosaccharides of the goblet cells. Moreover, N-linked oligosaccharides specifically contained Gal(beta1-4)GlcNAc, while AAA-positive Fuc was only detected in O-linked oligosaccharides. Some of these carbohydrates were only visualized after removal of N- or O-linked oligosaccharides, suggesting a high level of approximation between the oligosaccharide chains, that render the carbohydrate inaccessible to the lectins. Differences in the labelling pattern between the goblet cells of the surface epithelium and the upper half of the crypts, and those of the lower half of the crypts suggests a maturation process for the goblet cells, which modifies the oligosaccharide composition of the secreted glycoproteins, as they ascend throughout the crypts. This maturation process includes the incorporation of new carbohydrates (GlcNAc), and the masking (Neu5Ac(alpha2-3)-linked) or unmasking (Glc and GalNAc) of others.
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PMID:Lectin cytochemical characterization of the N- and O-linked oligosaccharides in the human rectum. 1093 15

The aim of this work is the characterization of the glycoconjugates of the spermatids during the spermiogenesis of the testis of an urodele amphibian, Pleurodeles waltl, by means of lectins in combination with several chemical and enzymatic procedures, in order to establish the distribution of N- and O-linked oligosaccharides in these cells. The acrosome was the most relevant lectin-labeled structure. The O-linked oligosaccharides contained DBA- and SBA-positive GalNAc, AAA-positive Fuc and PNA-positive Gal beta1,3GalNAc. Sialic acid was scarcely observed, the Neu5Ac alpha2,3Gal beta1,4GlcNAc sequence was found in N-linked oligosaccharides. Additionally, N-linked oligosaccharides containing HPA-positive GalNAc and AAA-positive Fuc were found. Moreover, with some lectins the acrosome showed a variable composition of the oligosaccharides in the different steps of the sperm maturation. Some residues were found only in the early steps in maturating acrosome, while others were in the later steps, showing that acrosomal glycoconjugates are modified during acrosome development in spermiogenesis. The changes observed during acrosome maturation suggest the existence of a predetermined pattern of storage of the acrosome components and a progressive compression of them.
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PMID:Lectin histochemical localization of N- and O-linked oligosaccharides during the spermiogenesis of the urodele amphibian Pleurodeles waltl. 1097 42