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I Axelsson

Publications and source records attributed to I Axelsson.

49 records · Page 3Linked to original sources
PubMed1984

Heterogeneity, polydispersity, and physiologic role of corneal proteoglycans.

Gel chromatography, affinity chromatography, ultracentrifugation, enzymic fragmentation, and analysis of amino acids, hexosamines and neutral sugars were used to characterize a heterogeneous fraction of proteoglycans from bovine corneal stroma. The results indicate that the fraction largely consists of a mixture of the 2 main types of corneal proteoglycans described earlier, namely keratan sulfate proteoglycans and chondroitin sulfate-rich proteoglycans with covalently bound oligosaccharides. Models for the structure of proteoglycans are suggested, an it is concluded that the molecular size of corneal proteoglycans makes them appropriate as 'spacers' between the collagen fibrils, a property important for corneal transparency. Cornea is softer than cartilage because corneal proteoglycans are less underhydrated than cartilage proteoglycans.

Amino Acid Sequence↗
PubMed1983

Proteoglycans from rabbit articular and growth plate cartilage. Ultracentrifugation, gel chromatography, and electron microscopy.

Proteoglycans are considered to be important for the mechanical properties of articular cartilage and growth plate and for the regulation of calcification of growth plate. We have used ultracentrifugation, gel chromatography, and electron microscopy to characterize and compare proteoglycans isolated from rabbit articular cartilage, uncalcified growth plate, and calcified cartilage. We found that proteoglycans from articular cartilage were more resistant to extraction than were proteoglycans from uncalcified growth plate and calcified cartilage. Long term neutral decalcification of calcified cartilage resulted in degraded proteoglycans. The chondroitin sulfate chains from all three tissues had similar size distribution. Gel chromatography and electron microscopy of proteoglycan monomers suggested that those from uncalcified growth plate were largest, those from articular cartilage intermediate, and those from calcified cartilage smallest. Proteoglycan aggregates from articular cartilage were longer than those from uncalcified growth plate. Both biochemical and quantitative electron microscopic data suggested the existence in mineralizing cartilage of at least two different sized populations of proteoglycan aggregates.

Animals↗
PubMed1983

Biosynthesis of rat growth plate proteoglycans in diabetes and malnutrition.

Insulin is an important growth factor in man and mammals. In the present investigation, we have studied the incorporation of (35S)-sulfate into growth plate proteoglycans in normal, diabetic, insulin-treated diabetic, and marasmic rats. We found that diabetes leads to an all-but-total stop in the synthesis of sulfated glycosaminoglycans. The glycosaminoglycan chains actually synthesized were shorter than in normal rats. The proteoglycan monomers were smaller and did not form large aggregates in vitro. Marasmic rats and insulin-treated diabetic rats were intermediate between normal and diabetic rats with respect to sulfate uptake by cartilage, incorporation of cartilage sulfate into glycosaminoglycans, and the chain length of glycosaminoglycans. We conclude that insulin and nutrition play important but different roles in the biosynthesis of growth plate proteoglycans and thus for the longitudinal growth of skeletal bones.

Animals↗
PubMed1983

Prenatal diagnosis of Potter's syndrome by ultrasound.

A variety of fetal anomalies can be diagnosed by ultrasonographic examinations during the antepartum period. This report describes the first Scandinavian case of Potter's syndrome detected prenatally. The syndrome must be suspected whenever the combination of intrauterine growth retardation and severe oligohydramnios is seen. It is then essential to scan for the presence of fetal kidneys to establish that bilateral agenesis is not occurring.

Abnormalities, Multiple↗
PubMed1979

Skeletal keratan sulfate from different tissues. Characterization and alkaline degradation.

Keratan sulfate-rich peptides were isolated after digestion of proteoglycans from bovine nasal cartilage and bovine nucleus pulposus with chondroitinase ABC, trypsin and chymotrypsin. The keratan sulfate enriched peptides from nucleus pulposus were larger than those from nasal cartilage. Keratan sulfate chains were isolated after treatment of the keratan sulfate-rich peptides under alkaline, reductive conditions. Proteoglycans from nucleus pulposus contain longer keratan sulfate chains, as is shown primarily by gel chromatography of the keratan sulfate-rich peptides and the keratan sulfate chains, but also from end-group analyses of the keratan sulfate chains.

Animals↗
PubMed1979

Proteoglycan structure of bovine articular cartilage. Variation with age and in osteoarthrosis.

Proteoglycan subunits (PGS) were isolated from bovine articular cartilage of calves and from cows, 18 months and 8 years old respectively. From the latter cartilage of osteoarthrotic and of non-osteoarthrotic sites was taken. PGS were characterized by gel-chromatography on Sepharose 2B columns and subjected to digestion with chondroitinase ABC and with papain. The isolated keratan sulphate-protein cores obtained from chondroitinase digestion were characterized on Sepharose 4B and the chondroitin sulphate chains on Sephadex G-200 gels. A larger molecular size of PGS was found in calf cartilage than in the other samples. This was attributed to the larger molecular size of chondroitin, whereas no change was observed in the keratan sulphate-protein cores. No change was observed in molecular size of PGS, isolated chondroitin sulphates or keratan sulphate-protein cores in osteoarthrosis in comparison with non-osteoarthrotic cartilage from the same joint or from younger adult animals.

Age Factors↗
PubMed1978

Characterization of the keratan sulphate proteoglycans from bovine corneal stroma.

The keratan sulphate proteoglycans that can be prepared from bovine corneal stroma [Axelsson & Heinegård (1975) Biochem. J. 145, 491-500] were characterized by gel chromatography, gel electrophoresis and analytical ultracentrifugation in associative (0.6 M-NaCl) and dissociative (6M-guanidinum chloride) solvents. The proteoglycans aggreagated at low salt concentrations and pH. The weight-average molecular weight of the monomer proteoglycans was established. Keratan sulphate peptides and oligosaccharide peptides were isolated after proteolysis. Their composition indicated that both are linked to protein via asparagine residues. A tentative model for corneal keratan sulphate proteoglycans is suggested.

Amino Acids↗
PubMed1977

Distribution of keratan sulfate in cartilage proteoglycans.

After chondroitinase digestion of bovine nasal and tracheal cartilage proteoglycans, subsequent treatment with trypsin or trypsin followed by chymotrypsin yielded two major types of polypeptide-glycosaminoglycan fragments which could be separated by Sepharose 6B chromatography. One fragment, located close to the hyaluronic acid-binding region of the protein core, had a high relative keratan sulfate content. This fragment contained about 60% of the total keratan sulfate, but less than 10% of the total chondroitin sulfate present in the original proteoglycan preparation. The weight average molecular weight of the keratan sulfate-enriched fragment was 122,000, as determined by sedimentation equilibrium centrifugation. The chemical and physical data indicate that this fragment contains an average of 10 to 15 keratan sulfate chains, if the average molecular weight of individual chains is assumed to be about 8,000, and about 5 chondroitin sulfate chains attached to a peptide of about 20,000 daltons. The other population of fragments was derived from the other end of the proteoglycan molecule, the chondroitin sulfate-enriched region, and contained mainly chondroitin sulfate chains. About 90% of the total chondroitin sulfate, but only 20 to 30% of the total keratan sulfate was recovered in these fragments. On the average, approximately 5 chondroitin sulfate chains and 1 keratan sulfate chain could be linked to the same peptide. Another 10 to 20% of the total keratan sulfate, originally found in or near the hyaluronic acid-binding region, was not separated from the chondroitin sulfate-enriched fragments. Hydroxylamine could be used to liberate a large molecular size, chondroitin sulfate-enriched fragment (Kav 0.54 on Sepharose 2B) from the proteoglycan aggregates. The remainder of the protein core, containing the keratan sulfate-enriched region, was bound to hyaluronic acid with the link proteins and recovered in the void volume on the Sepharose 2B column.

Amino Acids↗
PubMed1975

Fractionation of proteoglycans from bovine corneal stroma.

Proteoglycans were extracted from bovine corneal stroma with 4M-guanidinum chloride, purified by DEAE-dellulose chromatography (Antonopoulos et al., 1974) and fractionated by precipitation with ethanol into three fractions of approximately equal weight. One of these fractions consisted of a proteoglycan that contained keratan sulphate as the only glycosaminoglycan. In the othertwo fractions proteoglycans that contained chondroitin sulphate, dermatan sulphate and keratan sulphate were present. Proteoglycans which had a more than tenfold excess of galactosaminoglycans over keratan sulphate could be obtianed by further subfractionation. The gel-chromatographic patterns of the glucosaminoglycans before and after digestion with chondroitinase AC differed for the fractions. The individual chondroitin sulphate chains seemed to be larger in cornea than in cartilage. Oligosaccharides, possibly covalently linked to the protein core of the proteoglycans, could be isolated from all fractions. The corneal proteoglycans were shown to have higher protein contents and to be of smaller molecular size than cartilage proteoglycans.

Animals↗