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Biomedical subjects

A Lundblad

Publications and source records attributed to A Lundblad.

At least 109 records · Page 6Linked to original sources
PubMed1976

Quantitation of a urinary tetrasaccharide by gas chromatography and mass spectrometry.

A gas chromatographic mass spectrometric method has been developed for the rapid determination of a urinary tetrasaccharide (alpha-D-Glc-(1 leads to 6)-alpha-D-Glc-(1 leads to 4)-alpha-D-Glc-(1 leads to 4)-D-Glc). The urine sample is first fractionated by gel chromatography. An appropriate internal standard is added to the pooled tri-pentasaccharide fraction, which is then reduced, methylated and fractionated by g.c. The identification of the tetrasaccharide derivative is based on the g.c. relative retention time and the mass spectrum of the reduced permethylated tetrasaccharide. The normal excretion rate was in the range of 0.1-2.5 mg per 24 hours. Greatly increased amounts (9.4-89.6 mg 24 h-1) were found in the urine of patients with glycogen storage disease type II and type III and in one patient with unclassified muscular disease. A moderate increase (3.6m6 mg 24 h-1) was observed in one patient with glycogen storage disease type VI, in two patients with Duchenne muscular dystrophy and in two other patients with unclassified muscular disease.

Adolescent↗
PubMed1975

Specificity studies on alpha-mannosidases using oligosaccharides from mannosidosis urine as substrates.

Oligosaccharides containing terminal non-reducing alpha(1 leads to 2)-, alpha(1 leads to 3)-, and alpha(1 leads to 6)-linked mannose residues, isolated from human and bovine mannosidosis urines were used as substrates to test the specificities of acidic alpha-mannosidases isolated from human and bovine liver. The enzymes released all the alpha-linked mannose residues from each oligosaccharide and were most effective on the smallest substrate. Enzyme A in each case was less active on the oligosaccharides than alpha-mannosidase B2, even though the apparent Km value for the substrates was the same with each enzyme. The human acidic alpha-mannosidases were also found to be more active on substrates isolated from human rather than bovine mannosidosis urine. Human alpha-mannosidase C, which has a neutral pH optimum when assayed with a synthetic substrate, did not hydrolyse any of the oligosaccharides at neutral pH, but was found to be active at an acidic pH.

Animals↗
PubMed1975

A urinary pentasaccharide in bovine mannosidosis.

Abnormally high amounts of low molecular weight mannose-rich carbohydrate material were found in the urine of an Angus calf with mannosidosis. At least five oligosaccharide fractions were detected by paper chromatography. The most abundant compound was purified by gel chromatography, zone electrophoresis, and two consecutive preparative paper chromatographic steps. The yield was 10 mg/liter of urine. From structural studies including nuclear magnetic resonance spectroscopy, optical rotation, sugar analysis, methylation analysis, and partial enzymatic degradation the following structure was deduced: alpha-D-Manp-(1 leads to 6)-beta-D-Manp-(1 leads to 4)-beta-D-GlcNAcp-(1 leads to 4)-beta-D-GlcNAcp-(1 leads to 4)-D-GlcNAc. This oligosaccharide is distinct from all the oligosaccharides previously described which are excreted by patients with mannosidosis.

Acetylglucosamine↗
PubMed1975

A new type of carbohydrate-protein linkage in a glycopeptide from normal human urine.

A glycopeptide, 3-O-beta-D-glucopyranosyl-alpha-L-fucopyranosyl-L-threonine, has been isolated from normal human urine. The glycopeptide was isolated by gel chromatography, preparative zone electrophoresis, paper chromatography, and high voltage electrophoresis. The average yield of the glycopeptide was in the range of 0.2 to 0.3 mg/liter of urine. Sugar analysis and amino acid analysis gave equimolar amounts of glucose, fucose, and threonine. Linkages and sequential order were established by methylation analysis of the glycopeptide after degradation of the amino acid residue with ninhydrin. The permethylated product was analyzed on gas liquid chromatography and mass spectrometry. Anomeric configuration was deduced from optical rotation.

Chromatography, Gas↗
PubMed1975

The relationship between different forms of human alpha-mannosidase.

The tissue distribution and some properties of human alpha-mannosidase (alpha-D-mannoside mannohydrolase EC 3.2.1.24) have been studied. The acidic forms of the enzyme were fairly stable, whereas the neutral forms easily lost enzymic activity. The acidic forms were sensitive to neuraminidase but the neutral forms were unaffected. The experiments indicate that the acidic components are closely related to each other, differing only in sialic acid content and possibly conformation. The neutral forms of the enzyme are probably quite different from the acidic forms both in structure and cellular function.

Brain↗
PubMed1971

Immunochemical studies on blood groups. LI. A comparative study of the reaction of A 1 and A 2 blood group glycoproteins with human anti-A.

The immunochemical properties of purified A(1) and A(2) glycoproteins have been compared to ascertain whether their antigenic determinants differ. Quantitative precipitin and complement-fixation studies using several anti-A sera as well as purified gammaG anti-A antibodies clearly showed a specificity difference. This was also supported by absorption studies: A(2) substance specifically removed antibodies reacting with A(2) substance leaving anti-A(1) activity. A(1) substance was more effective than A(2) substance in dissolving an A(1) anti-A(1)-specific precipitate. Purified gammaM anti-A hemolyzed A(1) cells more readily than A(2) cells. Inhibition studies using mono- and difucosyl type 2 A-active oligosaccharides showed that type 2 difucosyl receptors are present in A(2) substance. The structural basis for the specificity difference between A(1) and A(2) would appear to be that A(2) substances lack type 1 A determinants; this would account for the observed higher H and Le(b) activity in A(2) substances.

ABO Blood-Group System↗