Search PubMed⌕ Search

Biomedical subjects

A Wasteson

Publications and source records attributed to A Wasteson.

87 records · Page 5Linked to original sources
PubMed1973

A novel assay for the biosynthesis of sulphated polysaccharide and its application to studies on the effects of somatomedin on cultured cells.

1. A simple method is described for the determination of small amounts of [(35)S]sulphated polysaccharide with 95-100% recovery in the range from 0.3 to 150mug of polysaccharide. 2. The method is based on precipitation with cetylpyridinium chloride of polysaccharide samples applied to filter paper. It is not significantly disturbed by the presence in the sample of a large excess of inorganic (35)SO(4) (2-). 3. Sulphated glucosamino- and galactosaminoglycans may be determined separately by treatment of the sample with chondroitinase ABC. 4. The method is applicable to the assay of [(35)S]sulphated polysaccharide biosynthesis in cell cultures. A stimulation of sulphate incorporation obeying a linear dose-response curve, was demonstrated in somatomedin-incubated fibroblast and glia cell cultures. 5. The described system provides a new assay method for somatomedin. 6. The stimulatory effect of somatomedin on the synthesis of [(35)S]sulphated polysaccharide appeared to be general, rather than specific, for a particular type of polysaccharide.

Cells, Cultured↗
PubMed1972

Mode of degradation of the chondroitin sulphate proteoglycan in rat costal cartilage.

1. Chondroitin sulphate was isolated from different regions of rat costal cartilage after extensive proteolysis of the tissues. The molecular weight, determined by gel chromatography, of the polysaccharide obtained from an actively growing region (lateral zone) near the osteochondral junction was higher than that of the polysaccharide isolated from the remaining portion of the costal cartilage (medial zone). 2. In both types of cartilage the molecular weight of chondroitin sulphate, labelled with [(35)S]sulphate, remained unchanged in vivo over a period of 10 days, approximately corresponding to the half-life of the chondroitin sulphate proteoglycan. The molecular-weight distribution of chondroitin [(35)S]sulphate, labelled in vivo or in vitro, was invariably identical with that of the bulk polysaccharide from the same tissue. It is concluded that the observed regional variations in molecular-weight distribution were established at the time of polysaccharide biosynthesis. 3. In tissue culture more than half of the (35)S-labelled polysaccharide-proteins of the two tissues was released into the medium within 10 days of incubation. The released materials were of smaller molecular size than were the corresponding native proteoglycans. In contrast, the molecular-weight distribution of the chondroitin [(35)S]sulphate (single polysaccharide chains) remained constant throughout the incubation period. 4. A portion (about 20%) of the total radioactive material released from (35)S-labelled cartilage in tissue culture was identified as inorganic [(35)S]sulphate. No corresponding decrease in the degree of sulphation of the labelled polysaccharide could be detected. These findings suggest that a limited fraction of the proteoglycan molecules had been extensively desulphated. 5. It is suggested that the initial phase of degradation involves proteolytic cleavage of the proteoglycan, but the constituent polysaccharide chains remain intact. The partially degraded proteoglycan may be eliminated from the cartilage by diffusion into the circulatory system. An additional degradative process, which may occur intracellularly, includes desulphation of the polysaccharide, probably in conjunction with a more extensive breakdown of the polymer.

Animals↗
PubMed1971

Nature of the interaction of chondroitin 4-sulphate and chondroitin sulphate-proteoglycan with collagen.

The electrostatic interaction of chondroitin sulphate and the chondroitin sulphate-proteoglycan with collagen was studied by chromatography of the glycosaminoglycan and the proteoglycan on a collagen gel. The observed binding between the macromolecules increased with decreasing pH and ionic strength, and was significant under physiological conditions. A study of the interaction between chondroitin sulphate and a preparation of soluble collagen, with a partition-equilibrium technique, afforded similar results.

Animals↗
PubMed1971

Properties of fractionated chondroitin sulphate from ox nasal septa.

1. Chondroitin sulphate was isolated from bovine nasal septa by precipitation with cetylpyridinium chloride after digestion of the tissue with papain. 2. The material was divided into two portions, one of which was partially degraded with testicular hyaluronidase. 3. Untreated and hyaluronidase-digested material were fractionated into a total of eleven subfractions by gel chromatography on Sephadex G-200 and Sephadex G-100 respectively. 4. Chemical analyses indicated that the composition of all the fractions was similar to that of chondroitin sulphate. However, electrophoresis revealed a charge-inhomogeneity in the low-molecular-weight fractions obtained after hyaluronidase digestion. 5. The physicochemical properties of the subfractions were investigated by sedimentation-velocity, diffusion and sedimentation-equilibrium studies, osmometry, viscometry and gel chromatography. The individual fractions were essentially monodisperse and showed molecular weights ranging from 2400 to 36000. 6. The relationship between the intrinsic viscosity and the molecular weight was [eta]=5.0x10(-6)xM(1.14), indicating that the chondroitin sulphate molecules assume a shape intermediate between that of a random coil and a stiff rod. 7. The relationship between the sedimentation constant and the molecular weight (>10(4)) was s(0) (20,w)=2.3x10(-2)xM(0.44).

Animals↗
PubMed1971

The distribution of sulphate residues in the chondroitin sulphate chain.

1. Electrophoresis of chondroitin sulphate, before and after partial degradation with testicular hyaluronidase, revealed charge heterogeneity of the degraded but not of the intact polymer. 2. Hyaluronidase-treated chondroitin sulphate was fractionated by gel chromatography. Two subfractions which were essentially monodisperse with regard to molecular weight (values of 8600 and 4800, respectively) were separated further by chromatography on Dowex 1. The resulting subfractions differed considerably with respect to their sulphate/disaccharide molar ratios. 3. Amino acid and neutral-sugar analyses of the Dowex 1 subfractions showed that the less sulphated fragments contained the carbohydrate-protein linkage region, whereas the high-sulphated fragments essentially lacked this constituent. It was concluded that chondroitin sulphate contains relatively less sulphate in the vicinity of the carbohydrate-protein linkage region than in the more peripheral portion of the polysaccharide chain.

Amino Acids↗
PubMedDate not supplied

Platelet-derived growth factor is structurally related to the putative transforming protein p28sis of simian sarcoma virus.

A partial amino acid sequence of human platelet-derived growth factor, the major mitogen in serum for cells of mesenchymal origin, has been determined. A region of 104 contiguous amino acids shows virtual identity with the predicted sequence of p28sis, the putative transforming protein of simian sarcoma virus (SSV). This similarity suggests a mechanism for transformation by SSV and other agents, involving expression of growth factors.

Amino Acid Sequence↗
PubMedDate not supplied

TGF-alpha and ErbB2 production in synovial joint tissue: increased expression in arthritic joints.

OBJECTIVE: Cell types present in synovial joint tissues and during synovitis are known to produce epidermal growth factor receptor (EGFR)/ErbB-1/HER-1 and the potent EGFR-ligand transforming growth factor-alpha (TGF-alpha) in vitro. Concomitant expression of TGF-alpha, EGFR, and ErbB2 gives a strong proliferative drive in vitro and in vivo. However, the presence of TGF-alpha and members of the EGFR/EGFR-ligand family has not been thoroughly investigated in joint tissue in vivo. We aimed to determine whether TGF-alpha, EGFR, and ErbB2 are present in human synovial joints, especially during rheumatoid arthritis (RA). METHODS: TGF-alpha protein was immunodetected in knee synovial fluid (SF) collected from 23 RA patients, eight patients with other arthritic conditions, two osteoarthritis (OA) patients, and six post-traumatic patients (control). TGF-alpha mRNA and TGF-alpha, ErbB2, EGFR, and CD68 immunoreactivity were detected in knee synovial biopsies (6 RA/2 OA/6 control) using in situ hybridization and immunohistochemistry. TGF-alpha mRNA was determined in SF cells by reverse transcription polymerase chain reaction (RT-PCR) and/or the Northern blot technique. RESULTS: TGF-alpha protein was found in the synovial membrane (SM) and in the majority of SF samples. TGF-alpha levels were significantly higher (p < 0.001) in SF of RA patients than controls, TGF-alpha protein and mRNA were increased and more widespread in SM of RA patients. In addition, white blood cells collected from RA SF expressed TGF-alpha mRNA. Immunoreactivity for ErbB2 was found in SM and was more widespread in RA patients than in controls. CONCLUSION: The presence of TGF-alpha in normal SF and SM may indicate a physiological maintenance function. The increased expression of TGF-alpha and ErbB2 in RA SF and SM may give rise to an abnormal growth pattern, contributing to inflammatory synovial hyperplasia.

Arthritis, Rheumatoid↗