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Biomedical subjects

M Wrann

Publications and source records attributed to M Wrann.

25 records · Page 2Linked to original sources
PubMed1979

Hormone-induced modification of EGF receptor proteolysis in the induction of EGF action.

A proposal that EGF action is mediated through enhanced internalization of EGF receptors is modified to account for more recent evidence. EGF receptors turn over at a rapid rate, and the maintenance of a steady state of EGF receptors on the cell surface is provided through a rapid synthesis of EGF receptors, balancing their removal. This rapid turnover of unoccupied receptors may arise through their internalization and proteolysis in the lysosomes, in much the same way as receptors are internalized and degraded when exposed to EGF, which enhances internalization. This provides a dilemmma for the endocytic activation concept, since slight enhancement of receptor internalization gives rise to a strong hormone response. This problem may be solved by the observation that EGF induces a change in its receptor, exposing an otherwise unavailable site for proteolytic cleavage. This hormone-dependent modification of receptors may be the critical step in the induction of responses to EGF and other hormones that are internalized with their receptors. Both platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) are shown to down-regulate EGF receptors, though transiently, placing still more stringent requirements on the specificity by which hormones might act through endocytic activation of their receptors.

Animals↗
PubMed1978

Isolation and characterization of the normal crossreacting antigen: homology of its NH2-terminal amino acid sequence with that of carcinoembryonic antigen.

The normal antigen, NCA, which crossreacts with the carcinoembryonic antigen, CEA, was purified from normal spleen tissue by an immunochemical purification method using insolubilized antibodies to either CEA or NCA. The highly purified NCA obtained was extensively characterized by immunological tests. The molecular weight of NCA determined by chromatography on Sephadex G-200 was approximately 100,000. The total amount of carbohydrate in NCA was 30%, compared to 60% in CEA. NCA and CEA also differed in sugar composition. The amino acid composition of NCA was nearly identical to that of CEA, except for the apparent presence of methionine in NCA but not in CEA. The sequence of the first 26 NH2-terminal amino acids in NCA was identical to that of CEA except at position 21, where alanine was found in NCA instead of valine in CEA.

Amino Acid Sequence↗
PubMed1978

Blood-group A and G specific structures in toad (Bufo) spawn. Comparative studies on three species (Bufo bufo, Bufo viridis, Bufo calamita).

Permethylation analyses of the spawn material of three toad (Bufo) species allow the conclusion that the serologically determinant group in Bufo bufo spawn is identical with that found in human and hog blood-group A substances (i.e. GalNAc(alpha1,3) [Fuc(alpha1,2)] Gal -), and the serologically determinant group in Bufo viridis and Bufo calamita spawn is identical with that found in blood-group H substances (i.e. Fuc(alpha1,2) Gal -).

ABO Blood-Group System↗