Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 ultrastructural cytochemistry of the alveolar-capillary "membrane" has been investigated. Dialyzed iron and high iron diamine staining demonstrated a layer containing sulfated mucosubstance at the basal surface of the membranous pneumocytes. In the same layer, fixation with an osmium tetroxide-potassium pyroantimonate solution yielded abundant fine precipitates which were abolished by inclusion of ehtylene glycol bis-N,N'-tetraacetic acid (EGTA) in the fixative. This cation-retaining layer could be interpreted as providing a mechanism for retarding cation transport from the basement membrane to the alveolar space. High iron diamine staining also demonstrated a layer of sulfated mucosubstance on the microvilli of the granular pneumocytes. This layer corresponded with a sialidase-resistant, dialyzed iron-reactive stratum which overlaid the sialomucin-rich cell coat.
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PMID:A cation-retaining layer in the alveolar-capillary membrane. 6 17

Using a modified colloidal iron reaction two positively reacting components in neutrophil leukocytes are discernible: 1. In neutrophils of unfixed smears the outer membrane or surface coat is stained. 2. After fixation with buffered formalin, formalin-sublimate or Helly's fluid a strongly reacting cytoplasmic component is demonstrable. After fixation with formalin-sublimate or Helly's fluid the latter has been proven to be sensitive against treatment with sialidase thus indicating the presence of sialic acid residues in neutrophil granulocytes.
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PMID:[Demonstration of neutrophil leukocytes on blood smears by a modified colloidal iron reaction (author's transl)]. 43 52

An autopsy case of diffuse malignant peritoneal mesothelioma in a young woman who showed a high serum level of CA125 is reported. Autopsy revealed extensive tumor involvement of the visceral and parietal peritoneum. The liver, spleen and other abdominal viscera were encased by tumor nodules. Histologically, the polygonal tumor cells were arranged mostly in a sheet-like fashion with a few tubular or papillary forms. No PAS reaction-positive mucin was recognized, but there was a strongly positive colloidal iron reaction. The colloidal iron positivity was effaced after combined treatment with hyaluronidase and sialidase. Immunohistochemically the tumor cells showed strongly positive reactions for CA125, epithelial membrane antigen (EMA) and cytokeratin, weak positivity for carcinoembryonic antigen (CEA) and focal positivity for vimentin. Ultrastructurally, the most characteristic feature was the expression of numerous long microvilli projecting from the tumor cell surfaces and abundant long desmosomes between the tumor cells. We consider that pretreatment using a combination of hyaluronidase and sialidase might be useful for the diagnosis of malignant mesothelioma. CA125 staining should be performed routinely in cases where this tumor is suspected.
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PMID:Diffuse malignant peritoneal mesothelioma in a young woman with a high serum level of CA125. 171 Apr 13

Lectin-horseradish peroxidase conjugates were used to study glycoconjugates in paraffin sections of dorsal roots of the rat spinal cord. Griffonia simplicifolia-B4 isolectin (GSA I-B4) and peanut agglutinin (PNA) stained strongly the nodes of Ranvier, localizing, respectively, terminal alpha- and beta-D-galactose. Sialidase digestion did not increase staining with PNA at the node of Ranvier, suggesting the presence of a neutral glycoconjugate. Staining of the nodal but not the internodal axolemma was observed with PNA. The outer surface of the myelin sheath in axons of the dorsal root stained strongly with GSA I-B4 but only weakly with PNA, demonstrating an abundance of terminal alpha-galactose. PNA staining was enhanced in this site by sialidase digestion, showing terminal sialic acid-beta-galactose dimers. The presence of sialic acid here was further evidenced by labeling of these membranes with the lectin derived from the slug, Limax flavus (LFA). Affinity for a high iron diamine-Alcian blue (pH 2.5) sequence demonstrated, in addition, the presence of sulfate esters in glycoconjugates on the outer myelin membrane. GSA I-B4 imparted strong reactivity to nonmyelinated fibers in the dorsal root and the spinal nerve. The present findings appear to reflect several localizations of biochemically described nervous system glycoproteins containing O-glycosidically linked side chains terminated by alpha- and beta-D-galactose.
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PMID:Histochemical localization of galactose-containing glycoconjugate at peripheral nodes of Ranvier in the rat. 257 43

Surgically obtained rectosigmoid mucosa ("transitional" mucosa, TM) adjacent to eight primary carcinomas was compared with diseased mucosa (DM) from eight patients without primary carcinoma and mucosa from two normal control subjects by mucin histochemical and morphologic techniques. No differences were found between TM and DM that might have suggested premalignant changes unique to TM. An excess of sialidase-susceptible sialomucins was found in both TM and DM, as was loss of the sulfomucin-sialomucin gradient usually found between normal crypts and surface cells. Increased sialic acid in TM and DM may represent a nonspecific response to injury or inflammation and has been found in other epithelia under similar circumstances. Sialidase also induced substantial reduction of periodic acid-Schiff (PAS) staining, probably due to loss of sialic acid since no other sugars were released during sialidase digestion, as determined by thin-layer chromatography analysis of post-digestion supernatants. Carcinomas generally showed more staining with PAS than with basic dyes; PAS staining was minimally reduced by diastase and sialidase but markedly reduced by phenylhydrazine interposition, suggesting that some type of neutral glycoprotein was responsible. Finally, it was found that overreliance on the high-iron diamine-Alcian blue technique as a single procedure is unwise; this procedure should be accompanied by the use of singly applied dyes, especially high-iron diamine, together with other enzymatic and staining procedures.
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PMID:Histochemical and morphologic studies of mucosa bordering rectosigmoid carcinomas: comparisons with normal, diseased, and malignant colonic epithelium. 257 14

Experiments were carried out to assess the susceptibility of normal and inflammatory bowel disease rectal mucus to desulphation and desialation by faecal extracts and by bacterial sialidase. The effects were assessed histochemically using a combined high iron diamine (HID) and alcian blue (AB) stain for sulphomucins and sialomucins. Rectal mucus in biopsies from controls (irritable bowel syndrome) and patients with ulcerative colitis or Crohn's disease was resistant to desialation by Clostridium perfringens sialidase, but susceptible to desialation and desulphation by bacteria-free extracts of normal faeces. Periodic acid-Schiff (PAS) staining of adjacent sections similarly treated showed retention of neutral mucus. One faecal extract selectively desulphated all 42 biopsies, causing the goblet cells to change from HID positive to AB positive, suggesting that most, or all HID positive cells also contain sialomucins. This alters the interpretation of previous histochemical studies. Faecal extracts from patients with active ulcerative colitis (n = 6) had desialating and desulphating effects similar to faecal extracts from normal subjects (n = 6). Ulcerative colitis (n = 21), Crohn's disease (n = 18), and control (irritable bowel syndrome) (n = 17) rectal biopsies all showed similar susceptibility to desulphation by a pooled normal faecal extract, but rectal biopsies from patients with Crohn's disease proved more resistant to desialation than control or ulcerative colitis biopsies (p less than 0.02). These studies imply that colonic mucus undergoes continual desulphation and desialation in vivo as a result of faecal enzyme activity that is probably mainly of bacterial origin. Altered susceptibility of colonic mucus to this may be important in the pathogenesis of colonic disease.
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PMID:Histochemical demonstration of desialation and desulphation of normal and inflammatory bowel disease rectal mucus by faecal extracts. 286 55

Mutants of Actinomyces viscosus T14V lacking type 1 or type 2 fimbriae or both were selected by their failure to react with rabbit antibodies against either or both fimbrial antigens. Immunospecific double labeling with iron dextran and ferritin-conjugated antibodies showed two types of fimbriae on individual cells of the parent organism, a single type on mutant strains with type 1+2- and type 1-2+ fimbriae and no labeled or unlabeled fimbriae on a type 1-2- fimbria-deficient strain. The mutational loss of one fimbrial antigen did not appear to affect expression of the other, since bacteria with one or two types of fimbriae bound similar amounts of a monoclonal antibody directed against the fimbrial antigen present on both bacterial phenotypes. The strong adsorption of strains with type 1+2+ or 1+2- fimbriae to saliva-treated hydroxyapatite and weak adsorption of those with type 1-2+ or no fimbriae was consistent with the known involvement of type 1 fimbriae in this attachment process. Similarly, the A. viscosus lectin was clearly associated with the expression of type 2 fimbriae, since only the strains with type 1+2+ or 1-2+ fimbriae participated in lactose-sensitive coaggregations with Streptococcus sanguis 34. Further studies using the fimbria-deficient mutant strains showed that aggregation of A. viscosus T14V in the presence of sialidase-treated human saliva involved both types of fimbriae, whereas neither type was required for the lactose-resistant coaggregation of the organism with certain streptococcal strains.
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PMID:Mutants of Actinomyces viscosus T14V lacking type 1, type 2, or both types of fimbriae. 290 12

The ultrastructure and histochemistry of the human urethral mucosa was studied. By scanning electronmicroscopy (SEM) the cover cell of the urethra was found to be polygonal and with a surface topography characterized by numerous microvilli and micro-ridges. By transmission electronmicroscopy (TEM) the cover cells were shown to be interconnected with tight junctions but to lack the asymmetric luminal membrane and the fusiform vacuoles that characterize urothelium above the bladder neck. Histochemical analyses showed the human urethral cells to harbour large amounts of glycogen, and the glycocalyx facing the urethral lumen displayed high affinity for alcian blue and colloidal iron, indicating the presence of acid mucopolysaccharides. The reactivity with alcian blue appeared at pH 2.5, but was abolished by pre-treatment with sialidase. Studies with TEM or using SEM with energy-dispersive X-ray spectrometry (EDX) confirmed the high content of acid mucopolysaccharides in the luminal glycocalyx of the cover cells by demonstrating high binding capacity for ruthenium red. The quantitative binding of ruthenium red was not influenced by pH shifts between 4.5 and 7.5. Utilizing the SEM + EDX technique, small variations in quantity of negative charge (i.e. of bound ruthenium red) were detected within individual cover cells, but considerable variations were found between cells. The significance of these physicochemical properties of the human urethral lining is discussed with special reference to the previously demonstrated liability of this mucosal surface to interact with microorganisms such as Escherichia coli, Staphylococcus saprophyticus and Neisseria gonorrhoeae.
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PMID:A histochemical and ultrastructural study of human urethral uroepithelium. 621 Oct 27

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.
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PMID:Cell specialization in collecting tubules of the guinea pig kidney: carbonic anhydrase activity and glycosaminoglycan production in different cells. 680 16

Transferrin is N-glycosylated glycoprotein and plays an important role in iron transport from sites of absorption and storage to sites of utilization. Chronic ethanol alters the normal microheterogeneity pattern of transferrin as a consequence of changes in the sialic acid content. However the underlying basis of this change in sialic acid contents of transferrin in alcohol abuse remains unclear. We have undertaken this study in order to investigate the effects of chronic ethanol in rats with respect to the hepatic rate of (i) transferrin synthesis based on labeled leucine incorporation, (ii) the incorporation of labeled N-acetyl mannosamine (NAM) into sialic acid residues of transferrin, and (iii) roles of specific sialyltransferase and sialidase at hepatic subcellular level. The results showed no significant difference in the incorporation of labeled leucine into transferrin at all levels between the control and ethanol group, whereas the incorporation of NAM into transferrin was significantly decreased by 84% (p < 0.001) both at the whole cell and Golgi level. Thus, the incorporation of labeled NAM relative to the incorporation of labeled leucine into hepatic transferrin was significantly decreased by 86% (p < 0.001) in chronic ethanol-treated animals as compared with the controls both at the whole cell golgi levels. These data are further supported by our finding of concomitant decrease in the activity of beta-galactoside alpha 2,6-sialyltransferase by 58% (p < 0.01) in ethanol-treated rats as compared with control animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of chronic ethanol on enzymes regulating sialylation and desialylation of transferrin in rats. 833 87


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