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- Smith, C.A., et al.
(författare)
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A simplified assay for the arylamine N-acetyltransferase 2 polymorphism validated by phenotyping with isoniazid
- 1997
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 34:9, s. 758-60
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Tidskriftsartikel (refereegranskat)abstract
- Human arylamine N-acetyltransferase (NAT) activity is determined by two distinct genes, NAT1 and NAT2, and the classical acetylation polymorphism in NAT2 has been associated with a variety of disorders, including lupus erythematosus and arylamine induced cancers. Over 50% of the white population exhibit a slow acetylator phenotype. The genetic basis of the defect has been identified and several DNA based assays are available for genotyping studies. We present here a simplified, rapid PCR based assay for the identification of the major slow acetylator genotypes and validate it using isoniazid as probe drug. This assay was 100% predictive of phenotype. The three genotypes (homozygous mutated, heterozygous, and homozygous rapid) corresponded to a trimodal distribution of Ac-INH/INH metabolic ratios (slow, intermediate, and rapid) without overlapping.
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- Andersson, K, et al.
(författare)
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YopH of Yersinia pseudotuberculosis interrupts early phosphotyrosine signalling associated with phagocytosis.
- 1996
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Ingår i: Molecular Microbiology. - 0950-382X .- 1365-2958. ; 20:5, s. 1057-69
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Tidskriftsartikel (refereegranskat)abstract
- The PTPase YopH of Yersinia is essential to the ability of these bacteria to block phagocytosis. Wild-type Yersinia pseudotuberculosis, but not the yopH mutant strain, resisted phagocytosis by J774 cells. Ingestion of a yopH mutant was dependent on tyrosine kinase activity. Transcomplementation with wild-type yopH restored the anti-phagocytic effect, whereas introduction of the gene encoding the catalytically inactive yopHC403A was without effect. The PTPase inhibitor orthovanadate impaired the anti-phagocytic effect of the wild-type strain, further demonstrating the importance of bacteria-derived PTPase activity for this event. The ability to resist phagocytosis indicates that the effect of the bacterium is immediately exerted when it becomes associated with the phagocyte. Within 30 s after the onset of infection, wild-type Y. pseudotuberculosis caused a YopH-dependent dephosphorylation of phosphotyrosine proteins in J774 cells. Furthermore, interaction of the cells with phagocytosable strains led to a rapid and transient increase in tyrosine phosphorylation of paxillin and some other proteins, an event dependent on the presence of the bacterial surface-located protein invasin. Co-infection with the phagocytosable strain and the wild-type strain abolished the induction of tyrosine phosphorylation. Taken together, the present findings demonstrate an immediate YopH-mediated dephosphorylation of macrophage phosphotyrosine proteins, suggesting that this PTPase acts by preventing early phagocytosis-linked signalling in the phagocyte.
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- Arencibia, I, et al.
(författare)
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Yersinia invasin, a bacterial beta1-integrin ligand, is a potent inducer of lymphocyte motility and migration to collagen type IV and fibronectin.
- 1997
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 159:4, s. 1853-9
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Tidskriftsartikel (refereegranskat)abstract
- The Yersinia pseudotuberculosis invasin protein was found to be a potent inducer of pseudopodia formation and chemotactic and haptotactic migration in human T lymphocytes. Checkerboard analysis confirmed that migration was directional. The Yersinia invasin triggered migration of otherwise poorly migratory normal T cells on fibronectin and in particular on collagen type IV, and augmented the migration of leukemic T cell lines on these components. Invasin-induced lymphocyte migration was inhibited by staurosporin that selectively prevented pseudopodia formation but, noteworthy, augmented adhesion. The motogenic and attractant properties of invasin (Inv) were mediated via beta1-integrins, as shown by lack of effect of Inv on the motility of a beta1-integrin-negative lymphoid cell line and inhibition of invasin-induced lymphocyte motility by anti-beta1 Abs. Inv was markedly more effective than the extracellular matrix components fibronectin, collagen type IV, and laminin, which also interact with lymphocyte beta1-integrins, with respect to induction of pseudopodia, chemotaxis, and haptotaxis. Thus, Yersinia invasin is a model ligand for induction of lymphocyte motility via beta1-integrins. The extraordinary capacity of Inv to trigger and guide T lymphocyte motility and potentiate lymphocyte migration to extracellular matrix components may be of pathogenetic significance for the movement of lymphocytes to extraintestinal sites secondary to Yersinia infection.
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