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PubMed1983

Serum glycoconjugates in children with schizophrenia and conduct and adjustment disorders.

The serum glycoproteins represented by the individual protein-bound carbohydrate components and glycosaminoglycans represented by the hexuronic acid contents were determined in the sera of black and Caucasian normal children and children with diagnoses of schizophrenia, conduct disorder, and adjustment disorder. There were no race-related or sex-related differences in glycoproteins and glycosaminoglycans in the sera of normal children. Although the serum glycosaminogltents were determined in the sera of black and Caucasian normal children and children with diagnoses of schizophrenia, conduct disorder, and adjustment disorder. There were no race-related or sex-related differences in glycoproteins and glycosaminoglycans in the sera of normal children. Although the serum glycosaminogltents were determined in the sera of black and Caucasian normal children and children with diagnoses of schizophrenia, conduct disorder, and adjustment disorder. There were no race-related or sex-related differences in glycoproteins and glycosaminoglycans in the sera of normal children. Although the serum glycosaminoglycans were significantly elevated in children with a diagnosis of schizophrenia, the levels were in normal range in children with conduct and adjustment disorders. All of the protein-bound carbohydrates were elevated in schizophrenic children. However, only arabinose and galactosamine were significantly elevated in children with a diagnosis of conduct disorder, while only galactosamine was elevated in children with adjustment disorder. The presence of arabinose in serum glycoprotein was confirmed by chemical ionization-mass spectrometry. The possible causes of the differential elevation of the glycoconjugates in psychiatric disorders in relation to the effect of stress and environment are discussed.

Adjustment Disorders↗
PubMed1985

Differences in density and distribution of surface glycoconjugates between normal and dystrophic mouse Schwann cells detected by statistical analyses of lectin-ferritin binding.

Cultures of Schwann cells and neurons from dorsal root ganglia of normal (C57bl/6J +/+) and dystrophic (C57bl/6J dy2j/dy2j) mice were labeled with wheat germ agglutinin (WGA) and Ricinus communis agglutinin (RCA-I) conjugated to ferritin. Statistical methods were used to compare the regional densities and distribution characteristics of lectin binding in these two types of Schwann cells, which differ in their capacities to ensheath and myelinate axons in vivo and in cultures. Regional variations in lectin binding densities and distributions were observed in both types of Schwann cells. WGA-ferritin was bound at lower densities in dystrophic mouse Schwann cells than in corresponding regions of normal cells. In both normal and dystrophic cells, WGA-ferritin was distributed at greater densities on the free surfaces of Schwann cells than on the substrate-associated surfaces. WGA-ferritin was clustered in all regions of both normal and dystrophic mouse cells. RCA-ferritin densities did not differ significantly between corresponding regions of normal and dystrophic mouse Schwann cells. However, in normal mouse Schwann cells, the density of RCA-ferritin was significantly greater in the thinner, peripheral processes of Schwann cells than in thicker perinuclear regions of the cells. Differences in the degree of RCA-ferritin clustering were also detected between normal and dystrophic Schwann cells. These results indicate that regional differences in the density and distributions of cell surface glycoconjugates occur in Schwann cells of normal and dystrophic mice.

Animals↗
PubMed1986

Lectin affinity and PAGE analysis of soluble axonally transported glycoconjugates in the rat visual system.

Recent reports of the transsynaptic transfer of wheat germ agglutinin (WGA) in several systems are consistent with the hypothesis that WGA binds to endogenous glycoproteins(s) which undergo transsynaptic transfer. Such molecules might be involved in trophic interactions between neurons. Since these hypothetical glycoproteins must be soluble proteins (it is unlikely that integral membrane proteins are exchanged between neurons) this preliminary study of the soluble, axonally transported glycoconjugates of the visual system was undertaken. Soluble, tritium-labeled macromolecules which accumulated in the rat lateral geniculate nucleus (LGN) and visual cortex after intraocular injections of tritiated fucose were studied by lectin affinity chromatography and polyacrylamide gel electrophoresis (PAGE). After correction for hematogenously or cerebrospinal fluid transported label, 9.6% of the radioactivity in the LGN and 17.9% of the radioactivity in the visual cortex was found in the soluble fraction of a phosphate-buffered saline homogenate. In the LGN, 31.3% of the axonally transported soluble label was bound by concanavalin-A (Con-A) agarose. The corresponding figure in the visual cortex was 25.7%. Most (greater than 90%) of the label which did not bind Con-A was soluble in 10% trichloroacetic acid (TCA). Eighty-eight percent of the label which bound Con-A was precipitated by 10% TCA. On 7.5% polyacrylamide SDS reducing gels, the Con-A bound material from either the LGN or the visual cortex migrated as a single peak near the origin of the gel (apparent molecular weight greater than 300,000 Da).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Studies on the liver sequestration of lymphocytes bearing membrane-associated galactose-terminal glycoconjugates: reversal with agents that effectively compete for the asialoglycoprotein receptor.

The removal of "effete" glycoproteins from the circulation represents a proposed physiologic role for the hepatocyte asialoglycoprotein receptor. Our experiments support the hypothesis that this receptor may also be directly involved in the removal from the circulation of cells bearing asialoglycoconjugates. We report that the enhanced liver localization of neuraminidase-treated lymphocytes can be competitively inhibited by the coinjection of asialofetuin (ASF). Fetuin itself was without effect. Competitive inhibition of the liver receptor allowed normal localization to lymphoid tissues of the enzyme-treated lymphocytes, a condition which persisted as long as free ASF was present in the circulation. Our studies support the concept that cell surface carbohydrates play an important role in the tissue distribution of circulating lymphocytes. The process of thymocyte maturation, bone marrow transplantation, and the adoptive immunotherapy with continuous T-cell lines represent conditions where recirculation potential may be influenced by the presence of galactose terminal glycoconjugates.

Animals↗
PubMed1984

Lectin labeling of sprouting neurons. III. Type-specific glycoconjugates on growth cones of different origin.

Ferritin conjugates of various lectins were used to determine the densities of surface carbohydrates on nerve growth cones produced by different classes of neuron. These neurons, from superior cervical and dorsal root ganglia, spinal cord, olfactory bulb, and cerebellum of the fetal rat, were grown as explant cultures, labeled with the probes, and then processed for quantitative electron microscopic analysis. It has been observed that each type of growth cone carries a characteristic set of lectin receptors on its surface, a "surface carbohydrate signature." Neurons derived from the neural tube generally exhibit lower levels of lectin binding sites on their growth cones compared with those derived from the neural crest. However, after neuraminidase treatment, lectin labeling is consistently dense for all growth cone types. These findings suggest (i) that neurons are programmed, possibly at the time of neurulation, to generate high- or low-sialic-acid patterns of surface carbohydrates on their growth cones according to their origin, and (ii) that the specific glycoconjugate pattern found for each type of neuron may be involved in selective cell-cell interactions during nervous system development.

Animals↗
PubMed1983

Monensin does not prevent recycling of plasma membrane glycoconjugates.

Plasma membrane glycoconjugates, internalized during fluid-phase pinocytosis in the macrophage cell line, P388D1, were found to be rapidly recycled to the cell surface, also in the case where the cells had been treated with 25 microM monensin for 80 min which resulted in a reduction of the pinocytotic uptake rate to 30%. The result is discussed in terms of the intracellular pathway of internalized membrane.

Animals↗
PubMed1980

Histochemistry of glycoconjugates of pleomorphic adenomas of minor salivary glands, with special reference to glycocalyx of tubular areas.

Histochemical characterization of glycoconjugates elaborated by palatal pleomorphic adenomas showed that glycoproteins, glycosaminoglycans, and perhaps glycolipids were present in both the "epithelial" and "connective tissue" components of these tumors, as well as in the distinct glycocalyx present in the luminal surface of tubular and cystic areas.

Adenoma, Pleomorphic↗
PubMed1985

Specific antibodies to diphtheria toxin and type 6A pneumococcal capsular polysaccharide induced by a model of semi-synthetic glycoconjugate antigen.

A molecular model of a carbohydrate-protein conjugate is described, involving the non-toxic mutant protein CRM197, serologically related to the diphtheria toxin, covalently bound to a characterized oligosaccharide derived from the molecular structure of type 6A pneumococcal capsular polysaccharide. Physicochemical and immunochemical characteristics of this oligosaccharide-protein conjugate were consistent with a molecule showing a molar carbohydrate/protein ratio of 8, an av. mol. wt of 75,000, and retention of complete immunochemical identity when tested towards the homologous antisera. The immunological characteristics obtained after immunization of 2 animal models showed a high immunogenicity of the glycoconjugate specifically directed towards diphtheria toxin and the type 6A pneumococcal capsular polysaccharide.

Animals↗
PubMed1987

Demonstration of a keratan sulfate proteoglycan and a mannose-rich glycoconjugate in corpora amylacea of the brain by immunocytochemical and lectin-binding methods.

The aim of the present report is to call attention to the fact that corpora amylacea (CA) of the brain have similar biochemical and immunological characteristics as the connective tissue matrix. We have demonstrated that CA reacted positively toward a monoclonal antibody that specifically recognized the polysaccharide determinant on cartilage proteoglycans. Material strongly bound to concanavalin A was demonstrated in CA, blood vessel wall and cartilage and suggested high levels of mannose in these structures. These findings are in agreement with the known fact that both brain and cartilage contain keratan sulfate and high mannose glycoproteins. We propose that CA may result from accumulation of glycoconjugates normally present in the brain tissue matrix as the result of aging.

Aged↗
PubMed1985

Modifications involved in brain glycoconjugate metabolism induced by neonatal capsaicin treatment.

Neonatal capsaicin treatment induces significant changes in rat brain glycoconjugate metabolism. All glycosyltransferase activity involved either in glycoprotein or glycolipid biosynthesis was strongly enhanced. Higher enzymatic activities were obtained when capsaicin-treated rats (T1) had received an additional capsaicin dose (T2). In this case, the fucosyl and galactosyltransferase activities were markedly increased. However, the enhancement of sialyltransferase activity only affects the biosynthesis of glycoproteins and is not correlated with a significant change in ganglioside content. The present results suggest that the modulation of the microsomal glycosyltransferase activity, after capsaicin treatment, could not be stated up through a direct lipid interaction or a change in membrane properties because the phospholipid brain content is not significantly modified.

Animals↗
PubMed1983

Impairment of human brain development: glycoconjugate and lipid changes in congenital athyroidism.

The brain glycoconjugates, glycosidases and lipids have been studied in a case of human congenital athyroidism never treated with hormonal replacement. Increase of membrane-bound mucopolysaccharides has been found in the grey matter. Total lipids in the white matter, and phospholipids, and total glycolipids and cholesterol in both white and grey matter were reduced. Sialic acid (NeuNAc) and hexosamines in the cytosol grey matter were significantly raised, while they were reduced in the membrane-bound grey fraction. These biochemical findings confirm impairment of the myelination process in human hypothyroidism as is well established in experimental hypothyroidism. The significant changes in the carbohydrate moieties of the brain glycoproteins focus attention on complex alterations of structure and function of the cell plasma membranes.

Adolescent↗
PubMed2005

Candidacy of LPS-based glycoconjugates to prevent invasive meningococcal disease: developmental chemistry and investigation of immunological responses following immunization of mice and rabbits.

Glycoconjugates were prepared by covalently linking the immunogenic protein carrier CRM(197) to O-deacylated lipopolysaccharide (LPS) derived from Neisseria meningitidis (strain H44/76), immunotype L3 galE LPS. This mutant strain elaborates a truncated LPS structure that displays immunological epitopes characteristic of 76% of Group B meningococcal (NmB) strains. CRM(197) was covalently linked either to the reducing glucosamine residue of the lipid A region of the O-deacylated LPS or to a 2-keto-3-deoxy-octulosonic acid (Kdo) residue in the inner core region of the O-deacylated LPS. In both rabbits and mice a much stronger IgG response to the immunising antigen was generated in those animals that received conjugates linked via the lipid A region. Sera from mice that were immunized with these conjugates were assayed for their reactivity with LPS, both mutant and wild-type, of several homologous and heterologous NmB strains. Sera obtained from mice immunized with conjugates in which the carrier protein was linked via the Kdo moiety were only able to react with O-deacylated, but not fully acylated (native), LPS from the homologous strain. However, sera obtained from mice that were immunized with conjugates, in which the carrier protein was coupled to the lipid A region, reacted predominately with inner core epitopes that contained phosphoethanolamine at the same 3-position of the distal heptose residue (HepII) of the inner core LPS as was present on the immunising antigen. Additionally it was observed that sera from rabbits immunised with lipid A linked conjugates, unlike the mice responses, were generally not as specific for LPS antigens that contained phosphoethanolamine at the same 3-position as was present on the immunising antigen, but showed a broader inner core recognition, whereas those rabbits that received the Kdo-linked conjugates gave only a very weak non-specific response to all immunotypes. Finally, the sera from two out of six mice that had received lipid A linked conjugates had bactericidal activity against L3 wild-type NmB strain 8047 and one of these was able to passively protect against meningococcal infection in an infant rat model. This study demonstrates evidence towards the proof-in-principle that by using Nm inner core LPS conjugates coupled via the lipid A region with an intact phosphoethanolamine at the O-3 position of the HepII of the inner core LPS, it is possible to elicit functional and protective antibodies against meningococcal infection.

Animals↗
PubMed2001

Tryptophan glycoconjugate as a novel marker of renal function.

PURPOSE: Neither serum creatinine concentration nor creatinine clearance assess renal function accurately. Serum creatinine concentration is affected by muscle mass, and the creatinine clearance overestimates the glomerular filtration rate because of tubular secretion of creatinine. The present study was designed to determine whether serum concentrations of 2-(alpha-mannopyranosyl)-L-tryptophan (MPT), a tryptophan glycoconjugate, can be used as a marker of renal function. METHODS: Clearances of MPT and of inulin were compared in normal rats and in rats with cisplatin-induced acute renal failure. We also compared the clearances of MPT and of creatinine with inulin clearance in 25 patients with chronic renal disease. Serum concentrations of MPT and creatinine as a function of MPT clearance were determined in 108 patients with chronic renal disease. RESULTS: There was strong linear correlation between clearances of MPT and inulin in rats (r = 0.97) and humans (r = 0.87), indicating that renal handling of MPT is similar to that of inulin. In humans, linear regression analyses indicated that MPT was a better indicator of inulin clearance than was creatinine clearance. At the same level of renal function, serum creatinine concentrations tended to be lower in patients with less muscle mass (as indicated by a urinary creatinine excretion <1,000 mg in 24 hours) than in those who excreted >1,000 mg in 24 hours, whereas serum MPT concentrations were not affected by creatinine excretion. CONCLUSION: MPT clearance can replace inulin clearance in the clinical setting. The serum MPT concentration is an accurate measure of renal function even in patients with diminished muscle mass, and thus is a better indicator of renal function than is the serum creatinine concentration.

Acute Kidney Injury↗
PubMed1986

Study by X-ray diffraction of the geometrical shape of glycoprotein sugar chains in two model glycoconjugates, a liposaccharide and a phospholiposaccharide, having the same sugar chain.

Two amphipatic, model glycoconjugates having the same sugar chain but differing in their hydrophobic component were studied by X-ray diffraction in concentrated water solution and in the dry state. The liposaccharide 2, obtained by linking the NH2-4 group of the asparagine residue of the glycoaminoacid obtained from hen ovotransferrin with the activated carboxylic acid group of palmitic acid exhibited a cubic structure in which the sugar chain adopted a slightly deformed, "T-shaped conformation". The phospholiposaccharide 3, obtained by linking the NH2-4 group of the asparagine residue of the same glycoamino acid with the primary amine group of dipalmitoylphosphatidylethanolamine through a suberyl bridge exhibited a lamellar structure in which the sugar chain adopted a "Y-shaped conformation". Thus, it was possible to induce a conformational change of the hen ovotransferrin sugar chain by changing the "hydrophobic residue" to which it is linked.

Animals↗
PubMed2001

Expression of glycoconjugates bearing the Lewis X epitope during neural differentiation of P19 EC cells.

The Lewis X (Le(x)) bearing glycolipids were noticeably increased in amounts during the course of neural differentiation of P19 EC cells induced by retinoic acid (RA, all-trans form). Applying neoglycolipid technology and in situ TLC-LSIMS, the oligosaccharide chains of these scarce Le(x) bearing glycolipids were partially characterized after released by endoglycoceramidase and subsequent conversion into neoglycolipids. In order to understand the enzymatic basis for the expression of Le(x) bearing glycolipids, we measured glycolipid, glycoprotein and oligosaccharide fucosyltransferase (Fuc-T) activities using appropriate substrates in P19 EC cells with or without RA treatment. All three Fuc-Ts were increased after RA treatment and the highest activity was in the differentiated neural cells. We then investigated the two possible Fuc-T genes that might be responsible for these changes using RT-PCR analysis. Mouse Fuc-TIX (mFuc-TIX) transcript was detected in all cell types but it was only strongly expressed in RA-induced aggregates and neural cells. In the case of mouse Fuc-TIV (mFuc-TIV) gene, its transcript was only detectable in RA-induced aggregates and not found in either undifferentiated or RA-induced neural cells. These results strongly support that RA induces only a transient expression of the mFuc-TIV gene in cell aggregates but a more persistent expression of the mFuc-TIX gene at the transcription level throughout neural cell differentiation. The mFuc-TIX gene is probably the main cause for the increased expression of Le(x) glycoconjugates during neural differentiation of P19 EC cells.

Animals↗
PubMed1984

Fine localization of sulphated and non-sulphated glycoconjugates in the rabbit oviduct during the estrous cycle.

An ultrastructural histochemical investigation was carried out to ascertain the localization of the glucidie components and to verify the histochemical modifications during the physiological estrogenic cycle of rabbit oviduct. Stainings were performed with high iron diamine (HID), low iron diamine (LID), dialized iron (DI), tannic acid-uranyl acetate (TA-U), and periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) methods. The findings indicated that the secretory activity is more intense in the isthmus than in the ampulla. Neutral glycoconjugates are localized both in the secreting elements of the ampulla and in those of the isthmus, while carboxylated and sulphated glycosaminoglycans are localized only in the secretory granules of the secreting elements of the isthmus.

Animals↗
PubMed1986

Glycoconjugates in nervous tissue and small cell lung cancer share immunologically cross-reactive carbohydrate determinants.

Small cell lung cancer (SCLC) is a bronchogenic carcinoma of neuroectodermal origin that expresses a variety of nervous system markers characteristic of neuroendocrine cells. In addition, SCLC cell lines and biopsies have been shown immunocytochemically to express an antigen recognized by HNK-1, a mouse monoclonal antibody which recognizes a surface antigen on natural killer cells and on the myelin-associated glycoprotein (MAG) and other nervous system glycoconjugates. Immunoblot data are presented which identify 2 groups of HNK-1-reactive plasma membrane glycoproteins with Mrs of about 80 000 and 130 000, respectively, from several SCLC cell lines. Using antibodies to MAG carbohydrate and protein determinants as probes, it is shown that the SCLC glycoproteins reacting with HNK-1 do not appear to share structural similarity with MAG apart from carbohydrate determinants. Using similar techniques with a panel of polyclonal antibodies, data are shown indicating that there is no cross-reactivity of SCLC proteins with other myelin proteins including P0, P1, P2, proteolipid protein and myelin basic protein. A possible role of the carbohydrate antigen in mediating nervous system disease associated with SCLC is suggested.

Animals↗