Search Results
Results 401 - 450 of 2012
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Tertov V V - - 2002
Earlier we have isolated from human plasma desialylated low density lipoproteins (dLDL) and showed that, first, dLDL induce cholesterol esters accumulation--the main process accompanying atherosclerosis development. Second, the process of lipoprotein desialylation took place in plasma, and, finally, sialic acids removed from LDL are transferred to other serum glycoconjugates. In ...
Ozen Naile - - 2002
In this study, we determined curcumin's anticancer and chemopreventive effects in mice bearing Ehrlich ascites tumor by evaluation of cancer biomarkers, sialic acid level and sialidase activity. Both plasma sialic acid level and sialidase activity increased significantly in the mice group with Ehrlich ascites tumor. When the tumor groups fed ...
Kohla Guido - - 2002
Gangliosides, carrying an O-acetylated sialic acid in their carbohydrate moiety, are often found in growing and developing tissues, especially of neuro-ectodermal origin. The most prominent one is 9-O-Ac-GD3, which is considered as an oncofetal marker in animal and human tumors like neuronal tumors, melanoma, basalioma or breast cancer, as well ...
Haas Wilfried - - 2002
During its normal life cycle, Diplostomum spathaceum cercariae attach to and invade fish intermediate hosts. They are also known to attach to various other aquatic animals in response to water currents, touch and carbon dioxide. The purpose of this study was to identify the specific stimuli used by D. spathaceum ...
Karwaski Marie-France - - 2002
The CMP-sialic acid synthetase (CMP-Neu5Ac, synthetase) is responsible for the synthesis of CMP-Neu5Ac, which is the donor used by sialyltransferases to attach sialic acid to acceptor hydroxyl groups in various polysaccharides, glycolipids, and glycoproteins. Since CMP-Neu5Ac is unstable and relatively expensive, the CMP-Neu5Ac synthetase is valuable for the preparative enzymatic ...
Bulai Tatiana - - 2002
Sialate pyruvate-lyases, also known as sialate aldolases (EC 4.1.3.3), reversibly catalyse the cleavage of free N-acetylneuraminic acids to form pyruvate and N-acetylmannosamine. These enzymes are widely distributed and are present in numerous pro- and eukaryotic cells, in which they are localized only in the cytosol. They play an important role ...
Blume Astrid - - 2002
Sialic acids comprise a family of terminal sugars essential for a variety of biological recognition systems. UDP-N-acetylglucosamine 2-epimerase catalyzes the first step of their biosynthesis. Periodate-oxidized UDP-N-acetylglucosamine, namely 2',3'-dialdehydo-UDP-alpha-D-N-acetylglucosamine, was found to be an effective inhibitor of this enzyme, compared with the periodate oxidation products of compounds such as UDP, ...
Martin Laura T - - 2002
Glycan chains on glycoconjugates traversing the Golgi apparatus are often terminated by sialic acid residues, which can also be 9-O-acetylated. This process involves competition between multiple Golgi enzymes. Expression levels of Golgi enzyme mRNAs do not always correlate with enzyme activity, which in turn cannot accurately predict glycan sequences found ...
Vimr Eric - - 2002
Most oropharyngeal pathogens express sialic acid units on their surfaces, mimicking the sialyl-rich mucin layer coating epithelial cells and the glycoconjugates present on virtually all host cell surfaces and serum proteins. Unlike the host's cells, which synthesize sialic acids endogenously, several microbial pathogens use truncated sialylation pathways. How microorganisms regulate ...
Ueda Haruko - - 2002
A lectin from the fruiting body of the Psathyrella velutina mushroom (PVL) was found to bind specifically to N-acetylneuraminic acid, as well as to GlcNAc (Ueda, H., Kojima, K., Saitoh, T., and Ogawa, H. (1999) FEBS Lett. 448, 75-80). In this study, the glycan sequences that PVL recognizes with high ...
Nicol B M - - 2002
Sialic acid changes in Dalton's lymphoma cells and other tissues of 10-12-week-old Swiss albino mice were investigated in relation to tumour growth in vivo and following cyclophosphamide (ip, 200 mg/kg body weight) or cisplatin (ip, 8 mg/kg body weight) treatment. Three to four animals of both sexes were used in ...
Benavides Sebastián H - - 2002
The typical and most consistent physico-histochemical properties of lipofuscin granules, such as autofluorescence, sudanophilia, acid-fastness, PAS-reactivity, and lectin reactivities for diverse saccharide moieties have been generally detected in tissue specimens of old humans and animals. The purpose of this study was, therefore, to explore possible sequential variations of each of ...
Scarfe G B - - 2002
1. The relationship between the in vivo metabolism of substituted anilines, in particular N-acetylation and subsequent formation of oxanilic acids, and their molecular physico-chemical properties has been investigated using computational chemistry and pattern-recognition methods. The methods revealed that the physico-chemical properties most important for N-acetylation and subsequent oxanilic acid formation ...
Uslu Ezel - - 2002
BACKGROUND: Significant elevations of serum sialic acid level have been documented in various diseases including in a variety of central nervous system disorders. But, in head injury, there is no any study on the serum and brain tissue sialic acid levels. So, we planned an experimental study to evaluate serum ...
Silva-Hernandez Eryck R - - 2002
Glycomacropeptide (GMP) was purified from goat sweet whey by anion-exchange and hydrophobic interaction chromatography. Approximately 0.06% (w/v) of sweet whey was recovered as GMP. Amino acid analysis of the GMP preparation showed that the content of phenylalanine (an amino acid that does not occur in goat GMP) was negligible, indicating ...
Alonso Edurne - - 2002
Glycoconjugates could play a role in cell adhesion and migration mechanisms, including the locomotive movements of the primordial germ cells (PGCs) during the development of the embryo. In the present work, we have studied by lectin histochemistry the presence of N-acetylgalactosamine (GalNAc) in the glycans of the Xenopus PGCs, as ...
Munster Anja-K - - 2002
5-N-Acetylneuraminic acid (Neu5Ac) is the major sialic acid derivative found in animal cells. As a component of cell surface glycoconjugates, Neu5Ac is pivotal to numerous cellular recognition and communication processes including host-parasite interactions. A prerequisite for the synthesis of sialylated glycoconjugates is the activation of Neu5Ac to cytidine-monophosphate N-acetylneuraminic acid ...
Sonnenburg Justin L - - 2002
The glycosidic linkage of sialic acids is much more sensitive to acid hydrolysis than those of other monosaccharides in vertebrates. The commonest sialic acids in nature are neuraminic acid (Neu)-based and are typically N-acylated at the C5 position. Unsubstituted Neu is thought to occur on native gangliosides of certain tumors ...
Rodrigues Marcio L - - 2002
Cryptococcus neoformans is a fungal pathogen associated with systemic mycoses in up to 10% of AIDS patients. C. neoformans yeasts express sialic acids on the cell wall, where they play an anti-phagocytic role, and may represent a virulence factor at the initial phase of infection. Since the nature of the ...
Compère Philippe - - 2002
The protein and glycoprotein content of four different neutral or acidic solvent extracts (0.5 M KCl, 10% EDTA, 0.1 N HCl, or 2% acetic acid) from the mineralized exoskeleton of a decapod crustacean, the Atlantic shore crab Carcinus maenas, were characterized by quantitative analysis of proteins, SDS-PAGE analysis, and probing ...
Bennett Eric S - - 2002
The isoform specific role of sialic acid in human voltage-gated sodium channel gating was investigated through expression and chimeric analysis of two human isoforms, Na(v1.4) (hSkM1), and Na(v1.5) (hH1) in Chinese hamster ovary (CHO) cell lines. Immunoblot analyses indicate that both hSkM1 and hH1 are glycosylated and that hSkM1 is ...
Ito Masaki - - 2002
An improved fluorometric HPLC method for sialic acid determination was developed by employing synthetic N-propionylneuraminic acid (NPNA) as an internal standard. A fixed amount of NPNA was added to a sialoglycoconjugate sample. After hydrolyzing sialioglycoconjugates with diluted sulfuric acid, the released sialic acids and NPNA were derivatized with a fluorogenic ...
Charter Neil W - - 2002
In this study we have examined how unnatural sialic acids can alter polysialic acid expression and influence the adhesive properties of the neural cell adhesion molecule (NCAM). Unnatural sialic acids are generated by metabolic conversion of synthetic N-acyl mannosamines and are typically incorporated into cell-surface glycoconjugates. However, N-butanoylmannosamine and N-pentanoylmannosamine ...
Maru Isafumi - - 2002
N-Acetylneuraminic acid (NeuAc), the representative of the family of sialic acids, is an important molecule in biological recognition systems. Currently, NeuAc-based novel pharmaceutical agents and diagnostic reagents for influenza viruses are highly required in medical fields, and larger amounts of NeuAc are in demand worldwide. NeuAc had been prepared either ...
Cerná Andrea - - 2002
Sialic acid is a component of glycoproteins that influences enzymatic and receptor functions of cells. During proliferation and differentiation of tissues, sialic acid can serve as a recognition determinant in intercellular communication and interactions of cells with the extracellular matrix. In the present study, sialic acid expression in relation to ...
Janega Pavol - - 2002
Autoimmune diseases of the thyroid gland are among the most frequent endocrine disorders. The present study analyzes expression patterns of sialic acids in these diseases. Three lectins specific for sialic acids were used for the histochemical analysis of surgical specimens of the thyroid gland: Tritrichomonas mobilensis lectin that stains all ...
Leung Joseph C K - - 2002
The mechanism of mesangial IgA deposition is poorly understood in IgA nephropathy (IgAN). Abnormal glycosylation of carbohydrate moieties in the hinge region of the IgA molecule has recently attracted much attention. In this report, we studied galactosylation and sialylation profiles in kappa- and lambda-IgA1 from patients with IgAN. Total serum ...
Sarasquete C - - 2002
Histology and histochemistry are useful tools to study reproductive mechanisms in fish and they have been applied in this study. In the bluefin tuna, Thunnus thymus L., oocyte development can be divided into 4 principal phases based on the morphological features of developing oocytes and follicles. The primary growth phase ...
Hermentin P - - 2002
A new in vitro potency assay for erythropoietin has been developed and compared to the exhypoxic polycythemic mouse bioassay for rhuEPO batch release, required according to Ph. Eur. 2001. Evaluation of 14 batches of EPO has shown that the new assay is highly sensitive and able to reveal subtle changes ...
Konya E - - 2002
Using seed crystal method, whole-urine method, and scanning electron microscopy, the inhibitory effects of sialic acid and osteopontin (OPN) on aggregation/growth of CaOx crystals were investigated. Using the seed crystal method, sialic acid showed an inhibitory effect on CaOx crystal aggregation/growth in a concentration-dependent manner, but almost no effect was ...
Parillo Francesco - - 2002
Glycoconjugates present in the various parts of the digestive apparatus (oesophagus, stomach, intestine) of 27, 34 and 44 days-old Umbrina cirrosa (L.) fries were characterised by means of lectin histochemistry in conjunction with sialidase digestion and KOH treatment. High amounts of carbohydrates were detected especially in goblet cells of the ...
Oetke Cornelia - - 2002
Sialic acids are critical components of many glycoconjugates involved in biologically important ligand-receptor interactions. Quantitative and structural variations of sialic acid residues can profoundly affect specific cell-cell, pathogen-cell, or drug-cell interactions, but manipulation of sialic acids in mammalian cells has been technically limited. We describe the finding of a previously ...
Kugimiya A - - 2001
A surface plasmon resonance (SPR) sensor using a molecularly imprinted polymer-coated sensor chip for the detection of sialic acid was developed. The thinly coated polymer was prepared by co-polymerizing N,N,N-trimethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate and ethyleneglycol dimethacrylate in the presence of p-vinylbenzeneboronic acid ester with sialic acid. The sensor showed a ...
Morimoto N - - 2001
Simultaneous analysis of sialic acids has been a challenging target, because sialic acids having N- or O-acetyl, glycolyl, and sulfonic acid ester groups are labile during their release from carbohydrate chains and analytical procedures. In the present paper, we propose a method using high-performance liquid chromatography coupled with eletrospray ionization ...
Bürgmayr S - - 2001
The occurrence of N-acetylneuraminic acid and N-glycolylneuraminic acid residues in preparations of the slug Arion lusitanicus (Gastropoda) was determined by sodium dodecyl sulphate electrophoresis of the proteins followed by lectin blots stained with the sialic acid specific lectin from Maackia amurensis, by the sensitivity of this binding to sialidase from ...
Ghosh P - - 2001
Although plasma carbohydrate-deficient transferrin (CDT) is considered a viable biochemical marker for chronic alcohol consumption, it is valid only when an individual's daily alcohol consumption exceeds 60 g. In addition, it is less sensitive in women drinkers than in men drinkers. We have established that chronic alcohol consumption impairs the ...
Vural P - - 2001
OBJECTIVE: Sialic acid, a terminal component of glycoproteins and glycolipids, is found to be elevated in many pathologic conditions, including preterm deliveries and uterine dysfunction. Along with increased lipid peroxides, it is one of the indices of oxidative stress seen in recurrent abortion. This article investigates whether changes in plasma ...
Tertov V V - - 2001
In earlier studies we have found that incubation of low density lipoprotein (LDL) with autologous blood plasma-derived serum leads to a loss of sialic acid from lipoprotein particles. In this study we demonstrated that sialic acid removed from LDL was transferred to glycoconjugates of lipoproteins, glycoproteins and sphingolipids of human ...
Jacobs C L - - 2001
Unnatural analogues of sialic acid can be delivered to mammalian cell surfaces through the metabolic transformation of unnatural N-acetylmannosamine (ManNAc) derivatives. In previous studies, mannosamine analogues bearing simple N-acyl groups up to five carbon atoms in length were recognized as substrates by the biosynthetic machinery and transformed into cell surface ...
Schilling B - - 2001
Haemophilus ducreyi is a Gram-negative bacterium that causes chancroid, a sexually transmitted disease. Cell surface lipooligosaccharides (LOS) of H. ducreyi are thought to play important biological roles in host infection. The vast majority of H. ducreyi strains contain high levels of sialic acid (N-acetylneuraminic acid, NeuAc) in their LOS. Here ...
Yohe H C - - 2001
Sialoglycosphingolipids (gangliosides) are membrane components of eukaryotic cells that modulate cell signal transduction events. Discrepancies exist in the published descriptions of the gangliosides present in the human peripheral monocyte/macrophage. Macrophages were isolated from healthy human volunteers by two different methods. Their ganglioside fractions were isolated and examined by 2D thin-layer ...
Mielnik G - - 2001
Sialic acids, that are important constituents of animal tissue glycoconjugates, are also present in antigens of some bacterial strains. Capsular polysaccharides with sialic acid have been extensively studied whereas little is known on lipopolysaccharides which contain sialic acid. The susceptibility of Gram-negative strains with sialic acid-containing lipopolysaccharides to the bactericidal ...
Shimizu T - - 2001
To examine the differential properties of mucous glycoproteins, we produced hypertrophic and metaplastic changes in goblet cells of rat nasal epithelium by intranasal instillation of ovalbumin (OVA) in OVA-sensitized rats, and by intranasal lipopolysaccharide (LPS) instillation. The epithelial mucosubstance was quantitatively examined by alcian blue-periodic acid-Schiff (AB-PAS) and lectin histochemistry. ...
Graves I L - - 2001
Red blood cells (RBC) become sensitized following the elution of strain 575 Newcastle disease virus (NDV). The neuraminidase (NA) in the haemagglutinin (HA)-sialic acid configuration is inactive. The HA on sensitized RBC agglutinates normal RBC. The sialic acid on normal RBC initiated reactivation of the NA-a newly described function. Then ...
Albani J R - - 2001
Calcofluor White is a fluorescent probe that interacts with polysaccharides and is commonly used in clinical studies. Interaction between Calcofluor White and carbohydrate residues of alpha1-acid glycoprotein (orosomucoid) was previously studied at low and high concentrations of Calcofluor compared to that of the protein. alpha1-Acid glycoprotein contains 40% carbohydrate by ...
Angata T - - 2001
Siglecs are immunoglobulin superfamily member lectins that selectively recognize different types and linkages of sialic acids, which are major components of cell surface and secreted glycoconjugates. We report here a human Siglec-like molecule (Siglec-L1) that lacks a conserved arginine residue known to be essential for optimal sialic acid recognition by ...
Meo C D - - 2001
A highly efficient synthesis of the human melanoma associated antigen GD(3) derivative has been described. A key feature of the synthetic approach was the use of sialyl donors that were protected with a C-5 trifluoroacetamide moiety. These sialyl donors gave high yields and excellent alpha-anomeric selectivities in direct glycosylations with ...
Mantey L R - - 2001
Sialic acids comprise a family of terminal sugars essential for a variety of biological recognition systems. N-Propanoylmannosamine, an unphysiological sialic acid precursor, is taken up and metabolized by mammalian cells resulting in oligosaccharide-bound N-propanoylneuraminic acid. N-Propanoylmannosamine, applied to endogenously hyposialylated subclones of the myeloid leukemia HL60 and of the B-cell ...
Lederkremer R M - - 2001
The most important glycoproteins of trypanosomatids are anchored by glycoinositolphospholipids (GIPLs) to their plasma membrane. In addition, free GIPLs have been described, for instance the lipopeptidophosphoglycan (LPPG) which is a major component of the surface of T. cruzi epimastigotes. An inositolphosphoceramide (IPC) is part of the LPPG and of glycoproteins ...
McGowen M M - - 2001
We have chosen E. coli K92, which produces the alternating structure alpha(2-8)neuNAc alpha(2-9)neuNAc as a model system for studying bacterial polysaccharide biosynthesis. We have shown that the polysialyltransferase encoded by the K92 neuS gene can synthesize both alpha(2-8) and alpha(2-9) neuNAc linkages in vivo by 13C-nuclear magnetic resonance analysis of ...
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