Publications by authors named "MacDermot J"

An inherited deficiency of the enzyme alpha-galactosidase A is manifest clinically as Anderson-Fabry disease. Most affected patients present with severe peripheral pain in childhood or early adult life, and frequently progress to multi-organ failure by the 4th or 5th decades. The present review examines the probable mechanisms that contribute to pain in these patients, and outlines some of the treatment options that are currently used.

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1. Arginine-specific ADP-ribosyltransferase (ART1) is expressed on the surface of a number of cell types, and catalyses the transfer of ADP-ribose from NAD(+) to target proteins. We investigated whether extracellular proteins such as growth factors may serve as substrates for this enzyme, with subsequent alteration in their biological activity.

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Full length cDNA encoding ADP-ribosyltransferase-1 (ART1) was generated from human skeletal muscle. A single base variation from the published sequence was observed (C770-->T), and was established as a polymorphism by the screening of a population of 50 Caucasians. The base variation predicted a nonconservative substitution of Leu for Pro at codon 257.

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mRNA from human polymorphonuclear neutrophil leucocytes (PMNs) was probed with cDNA encoding human skeletal muscle arginine-specific ADP-ribosyltransferase (ART1). A single 2.6-kb transcript was identified, which was similar in size to that observed in human skeletal muscle RNA.

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1. Arginine-specific ADP-ribosyltransferase (ART) activity has been implicated in white cell chemotaxis. In this study, we examined the capacity of a panel of structurally unrelated inhibitors and pseudosubstrates of ART to inhibit chemotaxis of A7r5 rat vascular smooth muscle cells in response to PDGF-BB.

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The posttranslational modification of proteins by the addition of an ADP-ribose group is mediated by ADP-ribosyltransferases, which are expressed widely in many eukaryotic tissues, including leukocytes. DNA encoding arginine-specific ADP-ribosyltransferases has been cloned from both polymorphonuclear neutrophil leukocytes and lymphocytes, and their primary structures are widely conserved, particularly in those domains of the enzyme implicated in NAD+ binding and catalysis. In most cases the enzymes are tethered to the outer aspect of the cell surface or are released directly from the cell surface.

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Mono(ADP-ribosyl)transferase activity has been detected on the external surface of human polymorphonuclear neutrophil leucocytes (PMNs). The corresponding cDNA has been cloned and shown to be identical to that derived from human skeletal muscle. Our results suggest that mono(ADP-ribosyl)transferase is involved in the transduction pathway mediating (i) receptor-dependent re-alignment of cytoskeletal actin and (ii) chemotaxis of PMNs.

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1. Mono(ADP-ribosyl)transferase activity has been identified on the external surface of human polymorphonuclear neutrophil leucocytes (PMNs). The enzyme is released from the plasma membrane by phosphoinositide-specific phospholipase C, suggesting a glycosylphosphatidylinositol (GPI) linkage of the enzyme to the plasma membrane.

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An Arg-specific mono(ADP-ribosyl)transferase activity on the surface of human polymorphonuclear neutrophil leucocytes (PMNs) was confirmed by the use of diethylamino-(benzylidineamino)guanidine (DEA-BAG) as an ADP-ribose acceptor. Two separate HPLC systems were used to separate ADP-ribosyl-DEA-BAG from reaction mixtures, and its presence was confirmed by electrospray mass spectrometry. ADP-ribosyl-DEA-BAG was produced in the presence of PMNs, but not in their absence.

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Exposure of NG108-15 cells to 50 mM nicotinamide [an inhibitor of mono(ADP-ribosyl)transferase] for 18 hr led to an increase in membrane associated Gs alpha measured either as cholera toxin substrate or by immunoblotting with a specific antiserum. Prolonged exposure of NG108-15 cells to iloprost is followed by homologous loss of iloprost sensitivity, and heterologous loss of fluoride-dependent activation of adenylate cyclase. Nicotinamide reversed the loss of fluoride sensitivity, but failed to restore iloprost-dependent activation of adenylate cyclase.

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The effect on insulin release of efaroxan, an alpha 2-adrenoceptor antagonist and a highly potent drug at imidazoline I1 receptors, and the effects of seven other imidazoline compounds selective for the imidazoline I1 or I2 receptors, were studied in the rat insulinoma cell line RIN-5AH. The cells released insulin in response to glucose (0.3-10 mM), and efaroxan (100 microM) potentiated glucose-induced insulin release.

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1. Structural analogues of a sulphated polysaccharide, dextrin sulphate, were synthesized and tested for their ability to block infection by HIV-1. Using the T-cell lines, C8166 and HPB-ALL, and the laboratory adapted strains of HIV-1.

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Treatment of NCB-20 neuronal hybrid cells in culture with 100 microM ATP, 100 microM carbachol or 1 microM bradykinin is followed by a transient rise in intracellular calcium ion concentration ([Ca2+]i). Exposure of these cells to any one of these three agonists (ATP, carbachol or bradykinin) is also followed by heterologous desensitization of responses mediated by either of the other two classes of agonist. The heterologous desensitization is not inhibited by Ro-31-2880 (a selective protein kinase C inhibitor), neither is it accompanied by a reduction in the receptor-dependent increase in inositol trisphosphate.

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Pretreatment of NG108-15 cells with 0.03-25 microM prostaglandin E1 (PGE1) produced decreases in the maximal stimulation of adenylate cyclase activity produced by iloprost, N-ethylcarboxamidoadenosine and sodium fluoride. The rate of desensitization to all three agents was dependent on the concentration of PGE1 used, but at each concentration of PGE1 the rate of loss of responsiveness to each agent was the same, suggesting that the decreases in responsiveness may be mediated by a single process.

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Endothelial cells possess beta-adrenoceptors linked to adenylate cyclase which may regulate several aspects of endothelial cell function. The potential for this second messenger system to be modulated by protein kinase C activity was investigated. Bovine aortic endothelial cells (BAECs) were cultured in the absence or presence of phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C.

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A 116 kDa protein in NG108-15 homogenates is labelled in the presence of [32P]NAD+. This protein was found to be poly(ADP-ribosyl)ated and appears to be a poly(ADP-ribosyl)transferase which has poly(ADP-ribosyl)ated itself. Sodium nitroprusside, an NO generating agent, also stimulates the labelling of this protein by [32P]NAD+, but this can only be seen in the presence of thymidine, which inhibits poly(ADP-ribosyl)transferase activity.

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