176 resultados para Stable Vector-Bundles

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


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We present an algebro-geometric approach to a theorem on finite domination of chain complexes over a Laurent polynomial ring. The approach uses extension of chain complexes to sheaves on the projective line, which is governed by a K-theoretical obstruction.

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Stable bisubstrate ligands of phosphoglycerate kinase (PGK) have been synthesised with AMP or ADP conjugated to hydrolytically-stable, symmetrical analogues of 1,3-bisphosphoglycerate and their binding to yeast PGK evaluated. Their Kds decrease with net negative charge, with a penta-anionic analogue 7 showing highest affinity - in accordance with its approximation to the transition state for the reaction catalysed by PGK.

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Background Childhood asthma is characterized by inflammation of the airways. Structural changes of the airway wall may also be seen in some children early in the course of the disease. Matrix metalloproteinases (MMPs) are key mediators in the metabolism of the extracellular matrix (ECM). Objective To investigate the balance of MMP-8, MMP-9 and tissue inhibitor of metalloproteinases (TIMP)-1 in the airways of children with asthma. Methods One hundred and twenty-four children undergoing elective surgical procedures also underwent non-bronchoscopic bronchoalveolar lavage (BAL). MMP-8, MMP-9 and TIMP-1 were measured by ELISA. Results There was a significant reduction in MMP-9 in atopic asthmatic children (n=31) compared with normal children (n=30) [median difference: 0.57 ng/mL (95% confidence interval: 0.18–1.1 ng/mL)]. The ratio of MMP-9 to TIMP-1 was also reduced in asthmatic children. Levels of all three proteins were significantly correlated to each other and to the relative proportions of particular inflammatory cells in BAL fluid (BALF). Both MMP-8 and MMP-9 were moderately strongly correlated to the percentage neutrophil count (r=0.40 and 0.47, respectively, P

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Glucagon-like peptide-1(7-36)amide (GLP-1) possesses several unique and beneficial effects for the potential treatment of type 2 diabetes. However, the rapid in-activation of GLP-1 by dipeptidyl peptidase IV (DPP IV) results in a short half-life in vivo (less than 2 min) hindering therapeutic development. In the present study, a novel His(7)-modified analogue of GLP-1, N-pyroglutamyl-GLP-1, as well as N-acetyl-GLP-1 were synthesised and tested for DPP IV stability and biological activity. Incubation of GLP-1 with either DPP IV or human plasma resulted in rapid degradation of native GLP-1 to GLP-1 (9-36),amide, while N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 were completely resistant to degradation. N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 bound to the GLP-1 receptor but had reduced affinities (IC50 values 32(.)9 and 6(.)7 nM, respectively) compared with native GLP-1 (IC50 0(.)37 nM). Similarly, both analogues stimulated cAMP production with EC50 values of 16(.)3 and 27 nM respectively compared with GLP-1 (EC50 4(.)7 nM). However, N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 exhibited potent insulinotropic activity in vitro at 5(.)6 mM glucose (P