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  • 1
    Electronic Resource
    Electronic Resource
    Changes in the fucose content of haptoglobin in breast and ovarian cancer: Association with disease progression (1994)
    Springer
    Glycoconjugate journal 1 (1994), S. 37-43 
    Details
    ISSN: 1573-4986
    Keywords: breast cancer ; fucose ; haptoglobin ; ovarian cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract There is increasing evidence for changes in fucosylation in cancer. Previously, we showed that the fucose-specific lectin,Lotus tetragonolobus, extracts an abnormal form of haptoglobin (Hp) from cancer sera. This study investigates the monosaccharide content of Hp obtained from women with ovarian and breast cancer at different stages of their disease. In both cancers, Hp fucose was low when the disease was benign or in remission and much higher when the disease was progressive. This occurred whether the data was expressed per mole of protein or per three mannose residues. Changes in other monosaccharides were minor compared with fucose. There were small increases in theN-acetylglucosamine and galactose content (per three mannoses) in ovarian cancer, suggesting that some glycan chains have increased branching. The latter was independent of disease activity which may be due to some indirect cause such as cytotoxic therapy or an inflammatory response. When ovarian cancer patients were in remission, the number of glycosylation sites on Hp was reduced. Hp isolated from patients with early, but not advanced breast cancer also appeared to have increased glycan branching. The increased fucosylated Hp may interfere with fucose-mediated adhesion reactions of cancer cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00917467
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Glycosylation of alpha-1-proteinase inhibitor and haptoglobin in ovarian cancer: evidence for two different mechanisms (1995)
    Springer
    Glycoconjugate journal 12 (1995), S. 211-218 
    Details
    ISSN: 1573-4986
    Keywords: Glycosylation ; alpha-1-proteinase-inhibitor ; haptoglobin ; ovarian cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The change in glycosylation of the two acute-phase proteins, alpha-1-proteinase inhibitor (API) and haptoglobin (Hp), in progressive ovarian cancer is different. This has been shown by monosaccharide analysis and lectin-binding studies of proteins purified from serum. In the glycan chains of API, there is decreased branching (more biantennary chains), less branches ending in alpha 2-3 sialic acid, more branches ending in alpha 2-6 sialic acid and more fucose, probably linked alpha 1-6 to the core region. On the other hand, Hp shows increased branching (more triantennary chains), more branches ending in alpha 2-3 sialic acid, less branches ending in alpha 2-6 sialic acid, and more fucose, probably in the alpha 1-3 linkage at the end of the chains. This is surprising because API and Hp are thought to be glycosylated by a common pathway in the liver. We have also shown that the fucose-specific lectin,lotus tetragonolobus, extracts abnormal forms of both Hp and API in ovarian cancer, but the expression of this Hp is related to tumour burden and the expression of this API is related to lack of response to therapy. It is suggested that this difference in the behaviour of API and Hp in ovarian cancer may be associated with the different changes in their glycosylation. Of the many mechanisms that could explain these findings, a likely one is that a pathological process is removing API with triantennary chains from the circulation. In addition to their normal roles (API-enzyme inhibitor and Hp-transport protein) these proteins are reported to have many other effects in biological systems, such as immunosuppression. As correct glycosylation of API and Hp is required for their normal stability/activity, changes in glycosylation could affect their functions in ovarian cancer and these modifications could alter the course of the disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00731322
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    An improved ELISA for the determination of sialyl Lewisx structures on purified glycoconjugates (1996)
    Springer
    Glycoconjugate journal 13 (1996), S. 1043-1047 
    Details
    ISSN: 1573-4986
    Keywords: sialyl Lewisx ; haptoglobin ; synthetic glycoconjugates ; ELISA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The membrane carbohydrate antigen, sialyl Lewis x (sLex), is involved in cellular adhesive interactions in many diseases, such as cancer, inflammation and thrombosis. This antigen is also found on soluble macromolecules, such as serum glycoproteins, but the precise role of soluble sLex in modifying disease processes, or reflecting the pathological changes is still unclear. Although methods were previously reported for the measurement of soluble sLex, many of these were not well characterised, measurements were mainly made on mixtures of molecules, and the anti-sLex antibodies were used at concentrations that made the assay expensive. In this study an ELISA has been devised that detects sLex in purified soluble glycoconjugates using the anti-sLex antibody, CSLEX 1. Commercially-available haptoglobin (Hp) and synthetic complexes of Lewis antigens with polyacrylamide were used as model substances in developing the procedure. Key steps were washing the antibody/antigen complex with ten times diluted salt solution to prevent dissociation of the complex and the use of bovine serum albumin for blocking non-specific interactions. The assay was shown to be very specific, its precision was in the range 6–12%, and it could detect less than a pmol of sLex. It could also distinguish between different densities of sLex on the same amount of glycoconjugate. Determination of sLex in Hp isolated from small groups of healthy individuals, cancer patients, and rheumatoid arthritis sufferers suggested that the antigen expression is increased in disease. This method, which is an improvement on those previously described, will be useful for determining sLex in many different types of soluble glycoconjugate, and used in combination with synthetic carbohydrate polyacrylamide complexes, will help to standardize measurements of soluble sLex in the future.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01053200
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    A general method for the complete deglycosylation of a wide variety of serum glycoproteins using peptide-N-glycosidase-F (1994)
    Springer
    Glycoconjugate journal 1 (1994), S. 253-261 
    Details
    ISSN: 1573-4986
    Keywords: deglycosylation ; glycoproteins ; haptoglobin ; PNGase-F
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Many indirect serum studies show changes in protein glycosylation in disease, but further progress will require direct investigation of oligosaccharide composition. Current methods of deglycosylation using PNGase-F often result in incomplete removal of oligosaccharides. This is an unsatisfactory situation because only small quantities of material are often available in clinical studies, glycosylation changes may occur in only a small proportion of the molecules and quantification of the released oligosaccharides may be unreliable. The ability of PNGase-F to deglycosylate haptoglobin (Hp) under different conditions has been investigated. Oligosaccharides were completely removed from 50μg of Hp by treatment for 24 h with PNGase-F in 50 mmol/l ammonium formate buffer, pH 8.6, in combination with sodium dodecyl sulphate, mercaptoethanol and Nonidet P40. This modified procedure was equally effective at removing oligosaccharides from other serum glycoproteins (α1 glycoprotein, α1, transferrin) and fetuin, and its efficiency was independent of the polymeric structure of the molecule or the amount of glycosylation. The method has the additional advantage of using 20% less enzyme than previous methods, which substantially reduces costs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00919333
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    Paper (German National Licenses)
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