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Biomedical subjects

B Westermark

Publications and source records attributed to B Westermark.

At least 271 records · Page 15Linked 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↗
PubMedDate not supplied

High affinity receptors for vasoactive intestinal peptide on a human glioma cell line.

Vasoactive intestinal peptide (VIP) bound with high affinity (Kd 0.13 nmol/l) to receptors on the human glioma cell line U-343 MG Cl 2:6. The receptors bound the related peptides helodermin, PHM and secretin with 10, 400 and 5000 times lower affinity, respectively. Deamidated VIP (VIP-COOH) and [des-His1]VIP bound with 10 and 100 times lower affinity. The fragment VIP(7-28) displaced 25% of the receptor-bound 125I-VIP whereas VIP(16-28) and VIP(1-22-NH2) were inactive. The binding of 125I-VIP could be completely inhibited by 10 mumol/l of the antagonists [N-Ac-Tyr1,D-Phe2]GRF(1-29)-NH2, [pCl-D-Phe6,Leu17]VIP and VIP(10-28); in contrast, the antagonist L-8-K was inactive. Affinity labeling showed that VIP bound to proteins with Mr's of 75 kDa, 66 kDa and 50 kDa, respectively. Following binding, the peptide was rapidly internalized, and at steady-state only 20% of cell-associated 125I-VIP was bound to receptors on the cell surface. The internalized 125I-VIP was completely degraded to 125I-tyrosine which was released from the cells. Degradation of internalized 125I-VIP was significantly reduced by chloroquine phenanthroline and pepstatin-A. Surface binding and internalization of 125I-VIP was increased 3 times by phenanthroline, and pepstatin-A caused a 5 times increase in surface binding. Chloroquine reduced surface-bound 125I-VIP, but caused retention of internalized 125I-VIP.

Glioma↗
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↗