Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of complex carbohydrates has been investigated cytochemically at the light and electron microscope levels in collecting ducts of the guinea pig kidney. The dialyzed iron method demonstrated acidic complex carbohydrate ultrastructurally on the outer surface of the apical and the basolateral plasmalemma of the principal cells and in their maturing Golgi cisternae and secretory granules. Glycoconjugate in these sites stained for sulfate esters with the high iron diamine method but lacked reactivity toward the periodic acid-thiocarbohydrazide-silver proteinate (PA-T-SP) sequence for visualizing vic glycol-containing glycoprotein. Lability to testicular hyaluronidase and resistance to sialidase identified the Glycosaminoglycan (GAG) in principal cell granules and the plasmalemmae as a chondroitin sulfate. In contrast, intercalated cells of the collecting ducts failed to stain with the cationic reagents, but showed light PA-T-SP reactivity demonstrative of neutral glycoprotein in the glycocalyx of the apical plasmalemma. Immunostaining with the immunoglobulin-enzyme bridge procedure localized carbonic anhydrase selectively to the intercalated cells. The ultrastructural and cytochemical observations on the guinea pig collecting ducts implicate intercalated cells in fluid and electrolyte transport and principal cells in secretion of a chondroitin sulfate to the tubule lumen and intercellular space.
Anat Rec 1982 Apr
PMID:Cell specialization in collecting tubules of the guinea pig kidney: carbonic anhydrase activity and glycosaminoglycan production in different cells. 680 16

Developing methods for in vitro synthesis of the carbohydrate structure Galalpha1-3Galbeta1-4GlcNAc-R (termed the alpha-galactosyl epitope) on human tumour cells may be of potential clinical significance in cancer immunotherapy. Tumour vaccines with this epitope would be opsonized in vivo by the natural anti-Gal antibody, which is present in large amounts in humans, and which interacts specifically with alpha-galactosyl epitopes. Binding of anti-Gal to alpha-galactosyl epitopes on tumour cell membranes is likely to increase uptake of the cell membranes by antigen-presenting cells, such as macrophages, via the adhesion of the Fc portion of anti-Gal to Fc receptors on these cells. This, in turn, may increase processing and presentation of tumour-associated antigens by antigen-presenting cells, and induce an effective immune response against tumour cells with these antigens. The present study describes a method for the synthesis of alpha-galactosyl epitopes on human cells (red cells used as a model) by recombinant alpha1,3galactosyltransferase (rec. alpha1,3GT) expressed in bacteria. Escherichia coli was transformed with cDNA of the luminal portion of New World monkey rec. alpha1,3GT linked to six histidines (His)6 at the N-terminus. The enzyme produced by the bacteria was isolated from bacterial lysates on a nickel-Sepharose column and eluted with imidazole. This recombinant enzyme displayed acceptor specificity similar to that of rec. alpha1,3GT produced in COS cells. Red cells were pre-treated with sialidase for exposure of N-acetyllactosamine acceptors, then subjected to rec. alpha1,3GT activity. This enzyme synthesized at least 4 x 10(4) alpha-galactosyl epitopes/red cell. These epitopes were found to be accessible for binding of anti-Gal, as well as Bandeiraea simplicifolia IB4 lectin. It is argued that the method presented can be used for the synthesis of alpha-galactosyl epitopes on membranes of autologous tumour vaccines in humans.
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PMID:alpha-galactosyl (Galalpha1-3Galbeta1-4GlcNAc-R) epitopes on human cells: synthesis of the epitope on human red cells by recombinant primate alpha1,3galactosyltransferase expressed in E.coli. 872 75

Type II pneumocytes were found to be preferentially located on thick elastic fibers which formed the main structural framework of the alveoli in humans. Eight lobes resected from eight patients with adenocarcinoma or atypical adenomatous hyperplasia and two lobes from two necropsies were examined. Four small specimens of normal lung tissue were obtained from each lobe fixed in a buffered formalin. Thick sections (200-300 microm) were stained with hematoxylin to contrast nuclei or with elastica staining to demonstrate elastic fibers and immunostained with an antibody against Thomsen-Friedenreich antigen after pretreatment with sialidase to visualize type II pneumocytes. Alveolar structure and the distribution of type II pneumocytes were examined in 3D reconstructions generated using a standard microscope, a personal computer and NIH-Image software. Nuclei including those of type I and type II pneumocytes and endothelial cells were distributed diffusely throughout the alveolar wall. Thick elastic fibers constructed the main structural framework of the alveoli and formed the sides of the polygonal alveoli. Type II pneumocytes were found to be linearly located along these thick elastic fibers. This previously undisclosed distribution of type II pneumocytes may be concerned with alveolar rapid movement.
Anat Rec 2000 01 01
PMID:Type II pneumocytes are preferentially located along thick elastic fibers forming the framework of human alveoli. 1060 46

Feed particle size effects on morphology and glycoconjugate pattern was investigated in the rabbit intestine. Rabbits fed with fine particles (2 mm) displayed more irregularly shaped, higher duodenal villi and deeper crypts in distal colon as well as higher number of goblet cells than coarse (8 mm) fed ones. Brush border expressed: (i) in duodenum, neutral/sulfated glycoconjugates and glycans binding MAL II, SNA, Con A than KOH-sialidase-PNA and DBA reactivity in fine and coarse fed rabbits, respectively, (ii) in cecum, mainly sulfoglycans in coarse fed rabbits, MAL II and PNA staining in all samples, and (iii) in distal colon few sulfoglycans and MAL II reactivity. Enterocytes bound MAL II in duodenum, Con A in cecum, DBA, and Con A in distal colon of all rabbits, SNA in distal colon of coarse fed ones. Brunner's glands displayed high presence of acidic/sulfated mucins in fine fed rabbits, neutral glycoconjugates and reactivity with MAL II, SNA, PNA, KOH-sialidase-PNA, and Con A in all rabbits. Goblet cells exhibited: (i) in duodenum neutral and sulfomucins as well as MAL II and KOH-sialidase-PNA staining, than SNA and DBA in fine and coarse fed rabbits, respectively, (ii) in cecum sulfated glycans, MAL II, SNA, KOH-sialidase-PNA, DBA reactivity, and (iii) in distal colon acidic/sulfomucins, MAL II and SNA staining, and DBA reactivity in fine fed specimens. Crypt cells exhibited neutral and PNA reactive glycoconjugates in the cecum. In the distal colon also acidic/sulfated glycans, and MAL II, KOH-sialidase-PNA, DBA; SNA staining showed weaker reactivity in fine fed rabbits, which bound Con A.
Anat Rec (Hoboken) 2011 Nov
PMID:Morphometric features and glycoconjugate pattern of rabbit intestine are affected by particle size of pelleted diets. 2196 45