Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Horseradish peroxidase (HRP), a glycoprotein rich in mannose groups, was used as a ligand to detect receptors for glycoproteins in formalin-fixed, frozen sections of rat liver. Specific binding of HRP occurred to surface membranes of sinusoidal cells but not to those of parenchymal cells. The binding sites were visualized after the peroxidatic reaction in erythrocytes had been suppressed by methanol-H2O2 and phenylhydrazine, the latter reagent also decreasing the nonspecific background adsorption of HRP. Several factors influencing the reaction were studied systematically. The specific binding of HRP to sinusoidal cells was greatly decreased or abolished when tissue blocks were fixed for longer than 1-2 h in a cold 4% formaldehyde solution and the frozen sections subsequently treated for 30 min in cold methanol. The specific binding of HRP increased when the concentration of HRP in the medium was increased from 10 microgram/ml to 40 microgram/ml, when the time of incubation with HRP was increased from 1 h to 4 h, or when the temperature of incubation with HRP was increased from 4 degrees C to 22 degrees C, the pH of the incubation medium was increased from 7.0 to 10.0. Little or no specific binding of HRP was observed in the absence of added Ca++. The binding of HRP was suppressed by 10 mM mannose or 0.004% mannan whereas the suppression of the binding reaction by galactose or galactan required 30-40 ties higher concentrations.
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PMID:Cytochemical detection of mannose-specific receptors for glycoproteins with horseradish peroxidase as a ligand. 627 29

[3H]-acetate is rapidly incorporated as the acetyl moiety into synaptosomal protein and the apparent rate appears to decrease after approximately 1-2 minutes. A second dose of labeled acetate given 6 minutes after the first shows the same time dependent process suggesting that the protein substrate is not depleted. The apparent fall-off in the rate may represent the approach to a steady state of the mixing of the added acetate with internal cold acetate. Veratridine or batrachotoxin appears to stimulate a deacetylation process and tetrodotoxin blocks the effect of veratridine. Several proteins are acetylated at least one of which appears to be a glycoprotein of relatively low molecular weight. The presence of cold pyruvate or glucose competes with the incorporation of labeled acetate; the implication is that glucose and pyruvate can serve as a source of acetyl CoA for protein acetylation. The studies suggest that acetylation-deacetylation processes may be involved in membrane function, possibly in ion and/or transmitter channels.
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PMID:Is acetylation of protein involved in membrane function? 632 44

The reticulum cell sarcomas (RCS) of SJL/J mice are of particular interest since they readily induce the proliferation of syngeneic T-lymphocytes. Previous cellular studies examined the antigens on the RCS which stimulated this response and suggested that the tumor expressed allogeneic I-region-associated (Ia) antigens normally associated with the E alpha:E beta molecular complex (S. M. Wilbur and B. J. Bonavida, Exp. Med., 153: 501-513, 1981). These particular Ia glycoproteins are not expressed on normal SJL/J cells due to a defect in the E alpha polypeptide synthetic pathway. However, the E beta subunit is synthesized normally by these animals but remains intracellular. The SJL/J-derived RCS may circumvent this defect in E alpha subunit biosynthesis. The aberrant synthesis of this polypeptide is thought to allow membrane presentation of an intact pseudoallogeneic Ia glycoprotein which utilized the normally dormant E beta s polypeptide. In the present study, two monoclonal antibodies directed against the Ia.7 specificity of the E alpha chain (13/18, 14-4-4S) were used to examine more directly the expression of this polypeptide on the tumor. Surprisingly, neither antibody was effective against the RCS in a direct complement-mediated cytolysis assay. Nevertheless, the tumor was found to specifically adsorb lytic activity of both the monoclonal antibodies. In addition, both a cold-cell competition assay and indirect immunofluorescence corroborated the data and indicated that the RCS does express detectable levels of the Ia.7 antigen. Normal spleen cells and lipopolysaccharide B-derived blasts from SJL/J mice were found in all experiments to be devoid of any specific reactivity with these monoclonal antibodies. In addition, continued in vivo passage of transplantable RCS was found to cause down-modulation of the Ia.7 specificities on these tumors. Newer RCS transplantable lines, however, expressed demonstrable levels of this alloantigen in both cellular and serological assays. The observed down-modulation could explain the difficulties encountered in defining this specificity on long-term transplantable RCS. In conclusion, the present serological study corroborates the early cell-binding data. An Ia.7 antigen is shown to be expressed on the RCS, yet this specificity could not be detected on normal SJL/J cells.
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PMID:Serological demonstration of an allogeneic Ia.7 antigen on the cell surface of SJL/J-derived reticulum cell sarcomas. 634 68

The concentration of proteins, sialo-glycoproteins and gangliosides and the ganglioside composition of 8 brain regions from normothermic and hibernating fat dormice (Glis glis) and from laboratory mice being acclimated to 6, 22 and 28 degrees C were investigated. During hibernation the concentration of sialo-glycoproteins and gangliosides decreased significantly in brain of dormice; the protein content remained uninfluenced. Cold-exposure of laboratory mice yielded generally a slightly decreased sialo-glycoprotein concentration in brain; the data on ganglioside concentration in the CNS were not uniform. The ganglioside composition of brain of laboratory mice being kept at different environmental temperatures did not show any alterations. The brain gangliosides of hibernating dormice in contrast to their normothermic counterparts are more polar (higher amount of GTlb and GQlb.). Most striking is the complete absence of a distinct ganglioside fraction (O-acetylated-GTlb) during hibernation. Brain gangliosides of normothermic dormice were found to be more sensitive against neuraminidase treatment than those of hibernating animals. The results are discussed with regard to modulatory functions of neuronal gangliosides for the process of synaptic transmission during seasonal adaptation.
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PMID:Brain gangliosides in hibernating dormice (Glis glis) and cold-exposed laboratory mice. 646 99

We examined the effect of nonenzymatic glycosylation on the ability of fibronectin, an extracellular glycoprotein that interacts with cell surfaces and matrix components, to bind to collagen and heparin. Nonenzymatic glycosylation was accomplished by incubation of the protein with glucose, both cold and [14C]-labeled, and documented by measurement of ketoamine-bound carbohydrate with the thiobarbituric acid assay. Effect on binding was assessed with affinity chromatography on heparin-Sepharose and gelatin-Sepharose, and with an in vitro assay that detects complexation of fibronectin with [3H]-heparin. Glycosylated fibronectin did not bind to these immobilized matrix components, and in vitro binding of the glycosylated protein was reduced compared with that of nonglycosylated fibronectin. Inhibition of heparin binding in the in vitro assay was observed even with levels of glycosylation about threefold those of control, which is comparable to the degree of glycosylation determined in fibronectin isolated from plasma of two patients with uncontrolled diabetes. The findings indicate that nonenzymatic glycosylation of fibronectin inhibits its binding to connective tissue components, and suggest that this process contributes to faulty integrity of extracellular matrices in diabetes.
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PMID:Inhibition of fibronectin binding to matrix components by nonenzymatic glycosylation. 647 61

A lectin from early long pod var. of Vicia faba seed has been purified to homogeneity on chitin. The purified lectin is shown to be homogeneous in nature by Bio Gel P - 150 gel filtration, fast protein liquid chromatography and polyacrylamide gel electrophoresis. The lectin is a glycoprotein with molecular weight of 51,000. The lectin molecule is possibly composed of two types of subunits devoid of any covalent linking through sulfhydryl groups, with molecular weights 9,000 and 15,000 respectively in the ratio 2:2. The purified lectin shows a high affinity for N-acetyl-D-glucosamine (GlcNAc). Amino acid analyses show that cysteine and methionine are absent, and a high proportion of aspartic acid and glutamic acid are present in the protein molecule. The extinction coefficient of the purified lectin is 7.22. The lectin behaves as a 'cold agglutinin' displaying stronger agglutination than the naturally occurring ABO agglutinin in the cold.
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PMID:Isolation and characterization of Vicia faba lectin affinity purified on chitin column. 651 78

Various parameters of fibrinolysis inhibition and the plasma concentration of fibronectin (alpha 2-surface binding glycoprotein, cold insoluble globulin) were measured in patients at risk of developing acute progressive respiratory sufficiency following trauma or sepsis - the delayed microembolism syndrome (DMS). Most parameters measuring fibrinolysis inhibition were significantly higher in the five patients with DMS than in five patients who did not develop the syndrome. Thus, the primary fibrinolysis inhibitor (alpha 2-antiplasmin) was enhanced and the alpha-form of this inhibitor, with affinity to plasminogen, showed the greatest increment and might be of major importance for the delayed elimination of fibrin from the lungs occurring in these patients. The fibronectin concentrations were not lower in patients with DMS than in those who did not develop the syndrome.
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PMID:Fibrinolysis inhibition and fibronectin in the blood in patients with the delayed microembolism syndrome. 664 94

Amyloid P component (AP/SAP), a glycoprotein, precipitated with purified snail galactans from Helix pomatia and Arianta arbustorum in a dose-dependent manner. Radiolabelled AP binds to human peripheral blood mononuclear cells (PBMC), erythrocytes, and cells derived from human non-T, non-B acute lymphocytic leukaemia. The AP cell binding is specific in that it is dose-dependent and can be blocked both by excess cold AP and by Helix pomatia galactan, although it cannot be blocked by an equal amount of the monosaccharide galactose. In vitro studies of human PBMC immune responses demonstrated that AP inhibits PBMC proliferation responses to mycobacterial purified protein derivative and to phytohaemagglutinin and the humoral, antibody response to pokeweed mitogen. The AP-induced suppression of non-specific antibody production by human PBMC was dependent on the time at which AP was added to the culture. AP was suppressive if added in the first 48 h of the 7-day culture, and the suppression could not be reversed by washing the cells after the exposure to AP. The mechanism of AP-induced immunosuppression is still unclear, but human SAP circulates as a pair of pentameric rings, having ten identical subunits that bind to galactose polymers, and our present data suggest that AP affects the immune response through its properties as a lectin.
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PMID:Human amyloid P component: a circulating lectin that modulates immunological responses. 671 82

The serum of a patient with bronchogenic carcinoma was found to contain a monoclonal IgM lambda (IgMwoo) that precipitated with a precursor blood group glycoprotein containing I and i determinants. IgMwoo did not agglutinate O cells in the cold or at room temperature, and by quantitative precipitin and precipitin inhibition assay its specificity was shown not to be to the I and i determinants. IgMwoo reacted best with lacto-N-tetraose, DGal beta 1 leads to 3DGlcNAc beta 1 leads to 3DGal beta 1 leads to 4DGlc, and was specific for the non-I or non-i determinant dGal beta 1 leads to 3DGlcNAc beta 1 leads to 3DGal-moiety present as a distinct chain on precursor glycoproteins containing I and i determinants. Human ovarian cyst blood group A and B glycoproteins were inactive, but removal of the outer tier of sugars involved in A, B, and H specificity exposed this non-I or non-i determinant as well as the determinant reacting with anti-I Ma. IgMwoo was neither a cold agglutinin nor a cryoglobulin. It precipitated with precursor blood group glycoproteins somewhat less at 37 degrees C than at 0 degrees C, the differences being ascribable to solubility.
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PMID:A monoclonal IgM lambda macroglobulin with specificity for lacto-N-tetraose in a patient with bronchogenic carcinoma. 679 16

The monoclonal antibody 13.1 recognizes an epitope on the T-200 glycoprotein and blocks natural killer (NK) lysis of the erythroleukemia target K562, but not of the acute lymphoblastic leukemia T cell target Molt-4. The inhibitory effect is at the killer cell level and not the target cell level, which suggests that 13.1 may react with a receptor on NK cells. This hypothesis was tested in assays to delineate precisely where in the NK cytolytic reaction sequence 13.1 interferes with lysis; 13.1 did not block initial NK-target cell interaction as measured in a target binding cell assay. With the use of a Ca++ pulse technique, 13.1 did not block any events occurring during Ca++-dependent programming. If the antibody was added after conjugate formation but before the addition of CaCl2 to initiate programming, however, full inhibition of NK lysis occurred. Therefore, 13.1 antibody defines a distinct stage in the NK reaction sequence that links target binding to the initiation of calcium-dependent programming events. NK cell binding alone is not sufficient to trigger lytic events, and the presence of a second structure or a distinct portion on a single structure is required to trigger lysis. We show that 13.1 blocks the ability of K562 to inhibit NK killing of Molt-4 in a cold target inhibition assay. Therefore, despite the fact that 13.1 does not disrupt conjugate formation, NK specificity may exist at a post-binding site rather than at the initial NK-target binding interaction. Our data suggest that the T-200 glycoprotein on NK cells triggers the initiation of the lytic events.
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PMID:Definition of a "trigger" stage in the NK cytolytic reaction sequence by a monoclonal antibody to the glycoprotein T-200. 688 18


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