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Biomedical subjects

G Strecker

Publications and source records attributed to G Strecker.

At least 127 records · Page 7Linked to original sources
PubMed1986

Induction of a protective immune IgE response in rats by injection of defined antigens of schistosomulum-released products: immunochemical properties of the target antigens.

Brown Norway rats were injected without adjuvant with the soluble products liberated in a 16-hour culture by schistosomula (schistosomula-released products, SRP-A). A strong cytotoxic and protective IgE response was elicited, mainly directed against 22- and 26-kilodalton (kDa) SRP-A molecules. In the present study, we have attempted to characterize further those molecules. Metaperiodate denaturing treatment of the SRP-A glycans before injection into rats did not modify the immunogenicity of the SRP-A antigens. Results obtained by lectin affinity suggested that the 22- and 26-kDa molecules were glycoconjugates binding to ConA. Preparative sodium dodecylsulfate electrophoresis has allowed the separation of enriched fractions of 22- and 26-kDa molecules which have been injected separately into rats. The corresponding sera were tested in antibody-dependent cell cytotoxicity and displayed a significant cytotoxic IgE response (65 and 53%, respectively) towards the larvae. These results lend further support to the view that the 22- and 26-kDa antigens are the major targets of the protective IgE response and thus appear as potentially protective antigens.

Animals↗
PubMed1985

Structure of two new oligosaccharides isolated from human milk: sialylated lacto-N-fucopentaoses I and II.

The structures of two minor oligosaccharides isolated from human milk have been investigated. By using f.a.b.-mass spectrometry, methylation analysis, and partial formolysis as the principal methods of structural investigation, these oligosaccharides were identified as IV2-alpha-Fuc-III6-alpha-NeuAc-LcOse4 and IV3-alpha-NeuAc-III4-alpha-Fuc-LcOse4. This latter oligosaccharide has been recently found to be the carbohydrate moiety of a ganglioside isolated from a colorectal carcinoma cell-line (see ref. 12).

Chromatography, Paper↗
PubMed1985

[Genetic disorders of N-acetylneuraminic acid metabolism: sialurias and sialidoses].

Sialuria and sialidosis represent the two known types of genetic errors of sialic acid metabolism. Sialuria type I (or "massive Sialuria") remains a very rare disease, characterized by the daily excretion of 10 g of N-acetylneuraminic acid. Although the primary defect has not been established, the absence of a feedback inhibition of the anabolic reactions is probably involved in the massive production of free sialic acid. Sialuria type II (Salla disease) and type III are lysosomal storage diseases and the patients have shown to have a 10 to 15 fold increase in the amount of free sialic acid in urine. These sialurias probably involve a defect in translocation of sialic acid from lysosomes to the site of biosynthesis. The sialidase deficiency has been found to be responsible of a number of storage diseases previously unclassified or described as "lipomucopolysaccharidosis" or "mucolipidosis I". The sialidase deficiency, or Sialidosis, is characterized by and increased urinary excretion of sialyloligosaccharides and storage of sialylated compounds. A third type of genetic error, the combined beta-galactosidase-sialidase deficiency, is due to the genetic deficiency of a 32 KD "protective protein" which is part of the complex formed between multimeric beta-galactosidase and sialidase.

Carbohydrate Conformation↗
PubMed1985

[Primary structure of the glycan chains of normal C 1 esterase inhibitor (C 1-INH) after NMR analysis at 400 MHz].

The primary structural analysis of O- and N-linked carbohydrate chains of the C-1-esterase inhibitor purified from normal serum was carried out by 400-MHz 1H-NMR spectroscopy. C-1-esterase inhibitor protein of a molecular weight of 116,000 daltons contains 24 O-glycans: NeuAc (alpha 2-3) Gal (beta 1-3) GalNAc, 4 N-glycans: NeuAc (alpha 2-6) Gal (beta 1-4) (GlcNAc (beta 1-2) Man (alpha 1-3) [NeuAc (alpha 2-6) Gal (beta 1-4) GlcNAc (beta 1-2) Man (alpha 1-6)] Man (beta 1-4) GlcNAc (beta 1-4) GlcNAc and 2 N-glycans: NeuAc (alpha 2-3) Gal (beta 1-4) GlcNAc (beta 1-2) Man (alpha 1-3) [NeuAc (alpha 2-3) Gal (beta 1-4) GlcNAc (beta 1-2) Man (alpha 1-6)] Man (beta 1-4) GlcNAc (beta 1-4) GlcNAc. 30% of the N-glycans are fucosylated.

Carbohydrate Conformation↗
PubMed1984

Binaural interaction effects on the auditory brainstem response of the cat and kitten.

The auditory brainstem response (ABR) is a series of volume conducted potentials that can be recorded from the scalp within 10 ms following auditory stimulation. Differences between ABRs evoked with binaural stimulation and those constructed by summing equivalent numbers of monaural stimulation to each ear indicate the presence of binaural interaction for some ABR potentials but not for others. In the present study, ABR binaural interactions were studied in both cats and kittens. Binaural interactions were not seen for waves 1-3 but were present at the latencies of waves 4, 5 and, in most cases, 6. The sound intensities used were selected to insure that acoustic cross-over, i.e. sound presented monaurally to one ear stimulating the other, did not influence binaural interaction effects. Experiments with cats that had been monaurally deafened confirmed that the effects observed were not due to acoustic cross-over. Systematic manipulation of stimulus rate and intensity produced marked changes in the level of binaural interaction. Increases in stimulation rate from 10 to 100 clicks/s reduced binaural interaction for wave 4 and reversed the direction of binaural interaction for wave 5. Wave 6 was not generally present at rates above 10 clicks/s. Reduction of stimulus intensity reduced binaural interaction for wave 4. Binaural interaction effects were at adult levels in kittens of 20 days for waves 4 and 5. Wave 6 was not present until 30 days of age. These data suggest a possible model of the physiological processes producing binaural interaction which is based on occlusion as seen in other areas of the nervous system. In such a model, convergent input becomes more important in driving the generators of some ABR potentials when the system is stressed (as, for example, by increased stimulus rate), than it is when the system is not stressed.

Age Factors↗
PubMed1984

Preliminary investigation of the structure of the carbohydrate component of Vicia graminea lectin, a plant glycoprotein.

Purified Vicia graminea lectin, isolated from seeds, was found to contain D-mannose, 2-acetamido-2-deoxy-D-glucose, L-fucose, D-galactose, and D-xylose in the molar ratios approximately 3.9:1.5:1.2:1.1:1.0. The oligosaccharides, obtained after hydrazinolysis of Vg-lectin, were N-reacetylated, reduced with sodium borohydride, and fractionated into two peaks. The first peak contained D-galactose, D-mannose, 2-acetamido-2-deoxy-D-glucose, and 2-acetamido-2-deoxy-D-glucitol in the molar ratios 6:3:2:0.7. After h.p.l.c. fractionation into five oligosaccharides, the second peak contained D-mannose, D-xylose, L-fucose, 2-acetamido-2-deoxy-D-glucose, and 2-acetamido-2-deoxy-D-glucitol. Methylation analysis suggested the following general structure for these oligosaccharides: (formula; see text).

Carbohydrate Conformation↗
PubMed1984

Abnormal galactoside excretion in urine of a patient with early myoclonic epileptic encephalopathy.

An abnormal carbohydrate pattern was found in urine of a patient with early myoclonic epileptic encephalopathy. Three major oligosaccharides have been isolated from the urine; structural studies including sugar analyses, methylation procedure and enzymatic hydrolysis allow us to propose the following structures: beta-Gal-(1 leads to 3)-Gal beta-Gal-(1 leads to 3)-beta-Gal-(1 leads to 3)-Glc beta-Gal-(1 leads to 3)-beta-Gal-(1 leads to 3)-Gal Such oligosaccharide structures have not previously been described in any biological fluid. The origin of these compounds, and the possibility of a specific metabolic defect are discussed.

Chemical Phenomena↗
PubMed1984

[Hereditary angioneurotic edema: a molecular disease caused by a defect in the O-glycosylation of C1 esterase inhibitor (C1-INH)].

A quantitative and qualitative study of neutral and aminosaccharides in C 1-esterase inhibitor (C 1-INH), protein of the complement system, was performed. We observe a mixed glycosylation of the molecule with an N-glycosylated: O-glycosylated chain ratio of 1: 4. The loss of the inhibitory activity of the molecule in hereditary angioedema (O ANH) is associated with an O-glycosylation deficiency which differs according to the two molecular variants: C 1-INH (1 A) and C 1-INH (II) previously described.

Angioedema↗
PubMed1983

Structure determination of the carbohydrate chains of rat alpha-fetoprotein.

By affinity chromatography on concanavalin A (ConA) linked to Sepharose, S-carboxymethylated rat alpha-fetoprotein could be separated into two molecular variants: a ConA-reactive and a ConA-nonreactive fraction. The carbohydrate chains were quantitatively released from the protein by hydrazinolysis. Based on methylation analysis and high-resolution 1H-NMR spectroscopy of the re-N-acetylated hydrazinolysates, the carbohydrate structures of the two ConA-molecular variants of alpha-fetoprotein were established. The ConA-reactive species contains two N-glycosidic carbohydrate units per molecule, both having the following structure: (formula; see text) The ConA-nonreactive species possesses also two N-glycosidically linked oligosaccharide chains per molecule; each of these has the following structure: (formula; see text)

Animals↗
PubMed1983

Carbohydrate structures of hen ovomucoid. A mass spectrometric analysis.

The apparently homogenous N-glycosidically-linked glycans 1, 7, 11 and 14 released by hydrazinolysis from hen ovomucoid were analysed by fast atom bombardment and electron-impact mass spectrometry after reduction and permethylation. The spectra support the primary structures established independently [FEBS Letters (1983) 152, 145-152] using methylation analysis, partial acid hydrolysis and 500 MHz 1H NMR spectroscopy. In addition to the major constituents present in fractions 1, 7, 11 and 14, four minor components not detected by other methods could be characterized with the aid of the mass spectrometry data as: Man2GlcNAcGlcNAc-o1, GlcNAc4Man3GlcNAc-o1, GlcNAc6Man3GlcNAc-o1 and GalGlcNAc6-Man3GlcNAc-o1. Our results show that the physical techniques used provide valuable data on the structure of complex glycans. In addition they can be employed to ascertain the homogeneity of the compounds examined as well as to detect trace amounts of homologs that might not be noticed by other methods.

Animals↗
PubMed1983

Primary structure of a novel N-glycosidic carbohydrate unit, derived from hen ovomucoid. A 500-MHz 1H-NMR study.

The N-glycosidic carbohydrate chains of hen beta-ovomucoid were released from the protein by hydrazinolysis, and separated by HPLC. Primary structural analysis of 3 major fractions was conducted by applying 500-MHz 1H-NMR spectroscopy in combination with methylation analysis. One of the fractions investigated appeared to consist of an intersected penta-antennary structure extended with one Gal residue. The location of the latter in a certain branch could be established unambiguously by NMR. This structure is a novel member of the family of N-glycosidic carbohydrates of glycoproteins.

Animals↗
PubMed1983

Structural studies of glycans isolated from rat plasma hemopexin.

After exhaustive pronase digestion, purification by gel filtration and affinity chromatography on concanavalin A, three glycopeptide fractions were obtained from rat hemopexin. Two fractions (I and II) were concanavalin A non-reactive and one (III) was concanavalin A reactive. On the basis of carbohydrate composition, methylation analysis and proton nuclear magnetic resonance spectroscopy, the primary structure of the glycan in fraction III is proposed as being a mixture of mono- and di-sialo-diantennae of the N-glycosidic, N- acetyllactosamine type. Hydrazinolysis of glycopeptides not binding to concanavalin A yielded mixtures of oligosaccharides for both fractions. These oligosaccharides were separated by HPLC; the molar composition of each of them is given. These data suggest that rat hemopexin contains, among others, a diantennary structure bearing three sialic acid residues.

Animals↗
PubMed1983

Study of carbohydrate material isolated from ultrafiltrates in patients with chronic renal failure.

We have isolated substances of molecular weight ranging between 350 and 2,000 daltons from ultrafiltrates of 3 patients treated by maintenance haemodialysis for chronic renal failure. Such substances might have a role in the genesis of uraemic toxicity. We have chiefly studied their carbohydrate content. Material was fractionated according to a procedure previously used to urine in healthy controls. Consecutive ion exchange, charcoal Celite and paper chromatography lead to the isolation and purification of oligosaccharides, glycopeptides, glucuronoconjugates and peptides. The different classes of carbohydrate material present in dialysis fluids from uraemic patients are close to those formed in normal urines. All the oligosaccharides in renal failure urine had have identified in normal urine. In a previous studies we have demonstrated that the levels of glucuronoconjugates are higher in the blood of uraemic patients. The glucuronoconjugates and their aglycones could have a toxic effect but a great part of them is removed by hemodialysis.

Carbohydrates↗
PubMed1982

A novel type of carbohydrate structure present in hen ovomucoid.

Hen ovomucoid is characterized by a high degree of microheterogeneity of its carbohydrate moieties, as was recently demonstrated by hydrazinolysis in combination with high performance liquid chromatography (Paz Parente, J., Strecker, G., Leroy, Y., Montreuil, J., and Fournet, B. (1982) J. Chromatogr., in press). This approach resulted in 17 oligosaccharide-alditol fractions; the major one could be purified to homogeneity. Primary structural analysis of this fraction was carried out by methylation analysis, partial acid hydrolysis, and 500-MHz 1H NMR spectroscopy. Combination of these techniques enabled the unambiguous determination of a novel type of asparagine-bound carbohydrate chain: (formula, see text).

Animals↗