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Biomedical subjects

G C Hansson

Publications and source records attributed to G C Hansson.

At least 73 records · Page 4Linked to original sources
PubMed1991

Purification and characterization of a membrane-bound and a secreted mucin-type glycoprotein carrying the carcinoma-associated sialyl-Lea epitope on distinct core proteins.

Two mucin-type glycoproteins detected by the monoclonal antibody C50, which reacts with the carcinoma-associated sialyl-Lewis a and sialyl-lactotetraose epitopes, were found in secreted and solubilized materials from the colon carcinoma cell line COLO 205. The larger glycoprotein (H-CanAg; heavy cancer antigen) was predominantly found in extracts of cells grown in vitro or as nude mice xenografts whereas the smaller species (L-CanAg; light cancer antigen) was the major component in spent culture medium and serum from grafted mice. Using detergent in the extraction buffer doubled the yield of H-CanAg, suggesting that this glycoprotein is membrane bound whereas the yield of L-CanAg was relatively unaffected. The two glycoproteins were purified from xenograft extracts and spent culture medium using perchloric acid precipitation, monoclonal antibody affinity purification, ion exchange chromatography, and gel filtration. Both glycoproteins were unaffected by reduction and alkylation in guanidine HCl. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, relative molecular masses were estimated to be 600-800 kDa for H-CanAg and 150-300 kDa for L-CanAg. Carbohydrate analysis revealed that the CanAg glycoproteins were highly glycosylated (81-89% carbohydrate by weight), carrying carbohydrate chains with average lengths of 13-18 sugars which were rich in fucose and sialic acid (2-3 residues/chain for each sugar). L-CanAg isolated from spent medium was glycosylated to a higher degree than its counterpart from xenograft extract. Immunochemical studies of the intact glycoproteins showed that both H-CanAg and L-CanAg expressed the monoclonal antibody-defined, sialic acid-containing carbohydrate epitopes CA203 and CA242 as well as the Lewis a blood group antigen whereas only H-CanAg appeared to carry the sialyl-Lewis x epitope. The amino acid compositions were typical of mucins, containing high amounts of serine, threonine (more than 25% together), and proline (11-18%). Significant differences in amino acid composition between H-CanAg and L-CanAg were found. A rabbit antiserum against the cytoplasmic C-terminal part of the MUC1 gene product, core protein of the carcinoma-associated polymorphic epithelial mucin (PEM) and DU-PAN-2, reacted with H-CanAg. After deglycosylation with trifluoromethanesulfonic acid, H-CanAg but not L-CanAg was recognized by the monoclonal antibodies SM-3 and HMFG-2, directed to the tandem repeat of the PEM apoprotein. However, these antibodies which react with PEM from mammary carcinomas without prior deglycosylation were unable to recognize intact H-CanAg, probably as a consequence of a more extensive glycosylation of this glycoprotein.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1991

Characterization of a novel A-active octaglycosylceramide with type 1 chain repeat inherited as a recessive trait in the epithelial cells of the small intestine of inbred rats.

Three strains of inbred rats, AVN, DA and LOU/M, were found to express human blood group A-active glycosphingolipids in the small intestine. Two A phenotypes were detected by immunostaining of thin layer chromatograms with monoclonal anti-blood group A antibody. One phenotype (DA and LOU/M) displayed a novel glycolipid which was characterized as an A-active octaglycosylceramide with a type 1 chain repeat by methylation analysis, electron-impact mass spectrometry of the permethylated and permethylated LiAlH4-reduced molecule, and 1H NMR spectroscopy. It was designated A-8. GalNAc alpha 1-3Gal beta 1-(3GlcNAc beta 1-3Gal beta 1)2-4Glc beta 1-Cer 2 Fuc alpha 1 It is the first description of a type 1 chain repeat in a linear glycolipid. Calculation of minimum energy conformations showed that the orientations of the oligosaccharide chain and A determinant of A-8 differ from those of the homologous structure with a type 2 chain repeat present in human erythrocytes (Hakomori, S., Stellner, K., and Watanabe, K. (1972) Biochem. Biophys. Res. Commun. 49, 1061-1068). Genetic analysis demonstrated that A-8 is inherited as an autosomal recessive trait.

ABO Blood-Group System↗
PubMed1991

Is there an intestinal natriuretic factor?

Intestinal tissue from cats was homogenized and fractionated by ultrafiltration to a molecular range of about 500-10,000 and separated by gel chromatography. The fractions from the gel filtrations were tested with regard to their ability to inhibit Na,K-ATPase as assayed with p-nitrophenylphosphate. The fractions that inhibited Na,K-ATPase were pooled and named pooled fraction 2. Pooled fraction 1 contained molecules larger, and pooled fraction 3 and 4 the molecules smaller, than pooled fraction 2. The four fractions were assayed for natriuretic 'activity' on anaesthetized rats. Administering pooled fraction 3 (no Na,K-ATPase-inhibiting activity) i.v. augmented renal excretion of sodium and water, whereas the other pooled fractions did not exhibit any consistent natriuretic effect. Cardiac ventricular tissue from cats was fractionated in the same manner as was done for the intestine. None of the cardiac fractions contained any natriuretic material. It is proposed that the cat small intestine contains a natriuretic factor.

Administration, Oral↗
PubMed1990

A novel sialidase which releases 2,7-anhydro-alpha-N-acetylneuraminic acid from sialoglycoconjugates.

The leech (Macrobdella decora) was found to contain two sialic acid-cleaving enzymes: an ordinary sialidase and a novel sialic acid-cleaving enzyme. This novel enzyme released 2,7-anhydro-alpha-N-acetylneuraminic acid (Neu2,7-anhydro5Ac) instead of alpha-N-acetylneuraminic acid (Neu5Ac) from 4-methylumbelliferyl-Neu5Ac, glycoproteins, and gangliosides. We have partially purified this novel sialidase from M. decora. We have also isolated Neu2,7-anhydro5Ac released from 4-methylumelliferyl-Neu5Ac and whale nasal keratan sulfate in pure form. The novel sialidase produced Neu2,7-anhydro5Ac only from sialoglycoconjugates, but not from free Neu5Ac. The structure of Neu2,7-anhydro5Ac produced by the novel sialidase was established by chemical analysis, mass spectrometry, and NMR spectroscopy. NMR analysis showed that instead of the original 2C5 conformation, the pyranose ring of Neu2,7-anhydro5Ac was in the 5C2 conformation, which makes the formation of the 2,7-anhydro bridge possible.

Animals↗
PubMed1990

Transient expression of type 2 chain in A-active hexaglycosylceramide of rat small intestine at weaning time. Demonstration by affinity chromatography and ceramide glycanase hydrolysis of A-active glycosphingolipids followed by gas chromatography and mass spectrometry of permethylated hexasaccharides.

The small intestine of 15- to 23-day-old rats was cut into four segments from the duodenum to the ileum. Neutral glycosphingolipids were purified from each segment and submitted to thin-layer chromatography and immunostaining with the A005 monoclonal anti-A antibody. This antibody detected an hexaglycosylceramide located mainly in the duodenum during the postnatal development. In order to characterize hexaglycosylceramides, blood group A-active glycolipids were purified by affinity chromatography on immobilized Helix pomatia lectin in organic solvent. Hexaglycosylceramides (A-6) were subsequently isolated by preparative thin-layer chromatography and hydrolyzed with ceramide glycanase. The free hexasaccharides were permethylated and analyzed by gas chromatography. Two peaks were detected in varying ratios during development, corresponding to type 1 and type 2 chain A hexasaccharides. Gas chromatography clearly demonstrated that type 2 A-6 occurred in the duodenum of developing rats, and that a shift from type 2 to type 1 A-6 occurred with growing age. The change from type 2 to type 1 chain was also assessed by methylation analysis, and by the variation of the characteristic fragmentations of type 1 and type 2 chain hexasaccharides upon mass spectometry of the permethylated A-6 oligosaccharides from the duodenum of 19-day-old and adult rats.

Aging↗
PubMed1990

Regional differences in the appearance of adult-type glycosphingolipids in the small intestine of inbred rats at weaning time.

The small intestine of 15- to 33-day-old rats was cut into four segments: duodenum, proximal jejunum, distal jejunum, and ileum. Neutral glycosphingolipids and gangliosides were purified from each segment and analyzed by thin-layer chromatography in order to study the developmental appearance of adult-type glycolipids at each level of the small intestine. Type 1 A-6 glycolipid was first detected in the ileum at 15 days and subsequently in the jejunum and duodenum at 19 days of age. N-Glycolylneuraminic acid was expressed first in the ileum at 17 days, then in the proximal jejunum at 21 days, but only after 29 days in the duodenum. In each region, 6-8 days were required between first detection and full expression of N-glycolylneuraminic acid. The presence of 2-hydroxylated fatty acids in glucosylceramide was found first in the ileum at 19 days, 2-3 days before appearing in the duodenum and proximal jejunum. A period of 2-3 days was necessary to reach full adult-type level of 2-hydroxylated fatty acids in glucosylceramide. These results show that adult-type glycolipids appear earlier in the distal than in the proximal region of the rat small intestine, and that different glycolipids appear at different times and at different rates. The finding that the biochemical differentiation of the whole small intestine expands over a period of 3 days to 2 weeks, depending on the region and the glycolipid, before being fully completed indicates that, in addition to the time lag observed between the distal and the proximal region, the new cells arising from the crypt of Lieberkhün after 15 days of age are not at once fully differentiated.

ABO Blood-Group System↗
PubMed1990

Glycosphingolipid receptors for Pseudomonas aeruginosa.

The binding of Pseudomonas aeruginosa to glycosphingolipids and to buccal and bronchial epithelial cells was analyzed. Three independently expressed specificities were found by bacterial binding to glycosphingolipids separated by thin-layer chromatography. All strains bound gangliotria- and gangliotetrasylceramide. All but one of the strains bound sialic acid-containing glycosphingolipids and lactosylceramide. The latter two specificities could be separated in that the lactosylceramide binding was retained and the sialic acid binding was suppressed when bovine serum albumin was used as a blocking agent in the thin-layer chromatography assay. The attachment to buccal epithelial cells, like the binding to sialylated compounds and lactosylceramide, was abolished by Formalin treatment of the bacteria, suggesting the importance of these specificities for cell adherence. In contrast, the binding to gangliotria- and gangliotetraosylceramide was retained by nonattaching Formalin-treated bacteria.

Antigens, CD↗
PubMed1989

The use of gas chromatography and gas chromatography-mass spectrometry for the characterization of permethylated oligosaccharides with molecular mass up to 2300.

Gas chromatography and gas chromatography-mass spectrometry were adapted for the analysis of large permethylated oligosaccharides of different types. Permethylated isomaltooligosaccharides with up to 11 sugar residues and a mass of 2291 Da and two branched blood group H-type decasaccharides derived from the corresponding glycosphingolipids with masses of 2150 Da were successfully analyzed. The capillary columns used have extremely good resolution exemplified by the separation of the two decasaccharides which only differed by one internal linkage position and by the separation of four isomeric tetrasaccharides. The combined information of retention times and mass spectra gave detailed information of 22 neutral oligosaccharides from porcine intestinal mucin and the approach thus allow quick screening of O-linked-type glycans. The procedure for permethylation of oligosaccharides using solid NaOH has been investigated and adapted for structures having a glucose alditol as in reduced oligosaccharides derived from milk and glycosphingolipids.

Animals↗
PubMed1989

Characterization of glycosphingolipid mixtures with up to ten sugars by gas chromatography and gas chromatography-mass spectrometry as permethylated oligosaccharides and ceramides released by ceramide glycanase.

A novel, effective method for structural characterization of glycosphingolipids has been devised. It employs ceramide glycanase to release intact oligosaccharides followed by analysis using high-mass gas chromatography-mass spectrometry. The oligosaccharides and ceramides released by the glycanase were permethylated and analyzed. The capillary gas chromatography gave excellent resolution and separated, for example, two isomeric 10-sugar oligosaccharides with a molecular mass of 2150 daltons differing only by a Gal1-3GlcNAc and a Gal1-4GlcNAc linkage. The oligosaccharides released from sialic acid containing glycosphingolipids (gangliosides) were also analyzed for monosialo compounds. This analytical approach is simple, is quick, and can readily allow quantitation of individual glycosphingolipids.

Ceramides↗
PubMed1989

Novel polyfucosylated N-linked glycopeptides with blood group A, H, X, and Y determinants from human small intestinal epithelial cells.

A novel type of N-linked glycopeptides representing a major part of the glycans in human small intestinal epithelial cells from blood group A and O individuals were isolated by gel filtrations and affinity chromatography on concanavalin A-Sepharose and Bandeiraea simplicifolia lectin I-Sepharose. Sugar composition, methylation analysis, 1H NMR spectroscopy of the underivatized glycopeptides and FAB-mass spectrometry and electron impact-mass spectrometry of the permethylated glycopeptides indicated a tri- and tetra-antennary structure containing an intersecting N-acetylglucosamine and an alpha (1----6)-linked fucose residue in the core unit for the majority of the glycans. In contrast to most glycopeptides of other sources, the intestinal glycopeptides were devoid of sialic acid, but contained 6-7 residues of fucose. The outer branches contained the following structures: Fuc alpha 1-2Gal beta 1-3GleNAc beta 1- (H type 1) Fuc alpha 1-2Gal beta 1-4GleNAc beta 1- (H type 2) Gal beta 1-4 (Fuc alpha 1-3)GlcNAc beta 1- (X) Fuc alpha 1-2Gal beta 1-4(Fuc alpha 1-3)GleNAc beta 1- (Y) GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-3GleNAc beta 1- (A type 1) GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-4GleNAc beta 1- (monofucosyl A type 2) GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-4 (Fuc alpha 1-3)GlcNAc beta 1- (trifucosyl A type 2) The blood group determinant structures were mainly of type 2, whereas glycolipids from the same cells contained mainly type 1 determinants. The polyfucosylated glycans represent a novel type of blood group active glycopeptides. The unique properties of the small intestinal glycopeptides as compared with glycopeptides of other tissue sources may be correlated with the specialized functional properties of the small intestinal epithelial cells.

ABO Blood-Group System↗
PubMed1988

A polarized epithelial cell mutant deficient in translocation of UDP-galactose into the Golgi complex.

Two lectin-resistant mutants derived from a polarized epithelial cell line have been described (Meiss, H.K., Green, R.F., and Rodriguez-Boulan, E.J. (1982) Mol. Cell. Biol. 2, 1287-1294). One of these mutants, the Madin-Darby canine kidney strain II cell line resistant to Ricinus communis agglutinin (MDCKII-RCAr), has been further characterized, and the biochemical defect leading to its altered phenotype has been determined. MDCKII-RCAr cells are shown to be enriched in cell-surface glycoconjugates bearing terminal N-acetylglucosamine residues by in vitro exogalactosylation and by labeling with fluorescent lectins. Binding assays with a sialic acid-specific lectin reveal a 70-75% reduction in sialylation of cell-surface glycoconjugates. The defect is pleiotropic in nature, affecting glycoproteins as well as glycosphingolipids. Analysis of glycosphingolipids shows a strong reduction of galactose-containing glycosphingolipids. Almost 90% of the glycosphingolipids are identified as glucosyl-ceramide. The mutant is not deficient in galactosyl- and sialytransferase activities. However, Golgi vesicles isolated from MDCKII-RCAr cells translocate UDP-galactose at only 2% of the rate observed for vesicles from wild-type MDCKII cells. The deficiency is specific, because translocation rates of UDP-N-acetylglucosamine and CMP-sialic acid are comparable for vesicles isolated from MDCKII-RCAr cells and wild-type cells. Despite the inability to translocate UDP-galactose into the lumen of the Golgi apparatus, MDCKII-RCAr cells are able to form monolayers with normal apical and basolateral polarity as shown by plasma membrane domain-restricted exogalactosylation.

Animals↗
PubMed1988

A blood group B-like pentaglycosylceramide is the major complex glycosphingolipid of the Madin-Darby canine kidney epithelial cell line I (MDCK I).

Two sublines of the epithelial cell line MDCK differ in glycosphingolipid composition (Hansson, G.C. et al. (1986) EMBO J. 5, 483-489). The Forssman pentaglycosylceramide was an abundant glycolipid in the MDCK II subline, but was absent in the MDCK I subline. The MDCK I line instead contained another five-sugar glycolipid in relatively large amounts. This component has now been isolated and characterized with mass spectrometry, methylation analysis, exoglycosidase digestion, and proton NMR spectroscopy. The structure was concluded to be Gal alpha 1----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1 Cer. This is a blood group B-like glycolipid lacking fucose, earlier found in rabbit and bovine erythrocytes.

ABO Blood-Group System↗
PubMed1988

Receptor analogs and monoclonal antibodies that inhibit adherence of Bordetella pertussis to human ciliated respiratory epithelial cells.

The adherence of Bordetella pertussis to human respiratory cilia is critical to the pathogenesis of whooping cough. To explore the development of agents that could interrupt adherence, the structure of the receptor on the ciliary surface was investigated. Using an in vitro adherence assay to human ciliated epithelial cells, galactose, lactose, and complex carbohydrates containing lactose eliminated adherence when preincubated with the bacteria. 10(-2) M galactose eluted adherent bacteria from cilia. B. pertussis and its two purified adhesins bound specifically to natural lactose-containing glycolipids in a TLC assay. mAbs to eukaryotic glycoconjugates with specificity for substituted galactose-glucose moieties blocked adherence when preincubated with ciliated cells. The carbohydrates that serve as receptors for B. pertussis on human cilia are galactose-glucose-containing glycolipids. Receptor analogs and anti-receptor antibodies effectively block adherence of B. pertussis to cilia and thus should be considered candidates for therapeutic intervention against disease.

Antibodies, Monoclonal↗
PubMed1988

Structural aspects of blood group glycosphingolipids in the gastrointestinal tract.

The epithelial cells of the gastrointestinal tract from different species show a very variable expression of blood group active glycosphingolipids. The core saccharide sequences are typical for the species as, for example, type 1 chains (Gal beta 1----3GlcNAc) are found in the small intestine of man, rat, and pig and type 2 chains (Gal beta 1----4GlcNAc) are found in the small intestine of dog, rabbit, and cat. The mouse is atypical with the ganglioseries as the major core saccharide of the small intestine. Blood group A determinants can be found in the small intestine of man, rat, dog, rabbit, and cat, and the blood group B determinant in man and rabbit. Studies on the blood group active glycosphingolipids along the gastrointestinal tract of rat have revealed a complex distribution. The glandular cells of the stomach and epithelial cells of the large intestine express blood group B active glycosphingolipids. The cores of these are the ganglioseries, and the isogloboseries in the stomach and the lacto- (type 1) and neolactoseries (type 2) in the large intestine. The type 2 component is only expressed as a difucosyl and the type 1 as a monofucosyl compound. The epithelial cells of the small intestine are devoid of blood group B glycolipids, but express blood group H structures of which some has a branched core saccharide. One rat strain is lacking blood group A structures in the small intestine, but another is converting the H precursors to blood group A compounds. Both these strains always express blood group A structures in the large intestine. The expression of blood group A glycosphingolipids in the small intestine is inherited as a dominant trait.

Animals↗
PubMed1988

The chemical basis for expression of the sialyl-Le(a) antigen.

The SLe(a) antigen, originally defined by monoclonal antibody 19-9, is a complex carbohydrate epitope that differs from the normal human blood group Lea antigen only by the presence of an additional sialic acid residue. SLe(a)-active oligosaccharides occur in both gangliosides and mucin-like glycoproteins in developing embryonic gut, as well as in many normal adult glandular tissues and secretions, but the antigen is virtually absent from normal adult gastrointestinal lumenal epithelial cells. Following malignant transformation of adult gastrointestinal lining epithelium and many other endodermally-derived glandular epithelia, SLe(a)-active mucins released from the ensuing tumor appear in blood plasma. The level of circulating SLe(a) antigen is currently being investigated as a means of following tumor recurrence, progression, and therapy. Recent studies on the biosynthesis of SLe(a) explain the observations that, 1) the antigen does not occur in individuals of Le(a-b-) blood group, and 2) individuals that belong to the Le(a+b-) blood group express SLe(a) more strongly than Le(a-b+) individuals. Further, the biosynthetic studies predict a new tumor antigen, NeuAc alpha 2-3Gal beta 1-3GlcNAc beta 1.... (the immediate precursor to SLe(a)) that should be expressed in Le(a-b-) individuals in nearly the same tissue distribution as found for the SLe(a) antigen in Le(a+b-) and Le(a-b+) individuals. Based upon studies of SLe(a) expression in normal saliva and the pathway for biosynthesis of SLe(a), it seems likely that future clinical studies could be profitably directed towards improving the predictive value of the plasma SLe(a) level by adjusting the quantitative results according to the Lewis blood group and ABH secretor phenotype of the individual patient.

ABO Blood-Group System↗
PubMed1988

Only trace amounts of fatty acids are found in pure mucus glycoproteins.

The presence of noncovalently associated lipids and covalently bound fatty acids was investigated in preparations of mucus glycoproteins obtained by using density-gradient centrifugation in CsCl/guanidinium chloride. No phospholipids, glycolipids, cholesterol, or triglycerides could be detected. However, small amounts of extractable fatty acids were consistently found, the sum of which ranged from 0.3 to 0.9 micrograms/mg of glycoprotein. The amount of fatty acid released after subsequent treatment with KOH ranged from 0 to 27 ng/mg of glycoprotein. We conclude that density-gradient centrifugation in CsCl/guanidinium chloride is very efficient in removing noncovalently associated lipids from mucus glycoproteins and that covalently bound fatty acids are probably not present in the macromolecules.

Animals↗