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- Dixelius, Johan, 1958-
(författare)
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Endothelial differentiation and angiogenesis regulation
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Angiogenesis can be defined as the formation of new blood vessels from pre-existing ones. Angiogenesis is required for development and maintenance of our vascular system and thus of fundamental importance to our existence. The endothelial cells that line the inside of the vessels de-differentiate, migrate, proliferate and re-differentiate during angiogenesis. Angiogenesis is tightly regulated, controlled by several angiogenic factors of various classes that promote angiogenesis but also by anti-angiogenic factors that counteract the effect of the pro-angiogenic factors. We have examined three factors involved in angiogenesis regulation, Vascular endotelial growth factor (VEGFR) -3, the matrix protein laminin-1 and the collagen XVIII derived fragment endostatin. Five tyrosine phosphorylation sites in the cytoplasmic tail of VEGFR-3 were identified by phosphopeptide mapping (PPM). The data was confirmed by PPM using point-mutated receptors generated by site-directed mutagenesis.Laminin-1 was found to promote angiogenesis in the chicken chorioallantoic membrane assay and in a synergistic fashion together with suboptimal levels of fibroblast growth factor 2 (FGF-2) in embryoid bodies. Laminin-1 also promoted endothelial tubular morphogenesis in vitro, and upregulated the expression of the endothelial differentiation marker Jagged-1. Endostatin was shown to affect endothelial FGF-2-induced cell survival and morphogenesis. This was a result of direct binding to endothelial cells and induction of tyrosine phosphorylation of many proteins including the adaptor protein Shb. The apoptotic and morphogenic responses induced by endostatin was shown to be dependent on Shb. Further, endostatin inhibited endothelial migration and affected molecules implicated in migration. In particular, FGF-2 induced actin reorganization, and β-catenin regulation was modulated by endostatin.
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| 2. |
- Palmgren, Helena, 1955-, et al.
(författare)
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Salmonella Aamager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter found in free-flying peregrine falcons (Falco peregrinus) in Sweden
- 2004
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Ingår i: Journal of Wildlife Diseases. - : Wildlife Disease Association. - 0090-3558 .- 1943-3700. ; 40:3, s. 583-587
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Tidskriftsartikel (refereegranskat)abstract
- Rare species with small population sizes are vulnerable to perturbations such as disease, inbreeding, or random events. The threat arising from microbial pathogens could be large and other species could act as reservoirs for pathogens. We report finding three enteric bacterial species, Salmonella Amager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter, in nestling free-flying peregrine falcons (Falco peregrinus) in Sweden in 2000. Cainpylobacterfied inarked genetic similarities to an isolate froin a human, providing a possible association between a human-associated strain of this bacterinin and peregrine falcons.
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| 3. |
- Palmgren, Helena, 1955-, et al.
(författare)
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Salmonella in sub-Antarctica : low heterogeneity in salmonella serotypes in South Georgian seals and birds
- 2000
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Ingår i: Epidemiology and Infection. - : Cambridge University Press. - 0950-2688 .- 1469-4409. ; 125:2, s. 257-262
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Tidskriftsartikel (refereegranskat)abstract
- The number of human visitors to Antarctica is increasing rapidly, and with it a risk of introducing infectious organisms to native animals. To study the occurrence of salmonella serotypes in sub- Antarctic wildlife, faecal samples were collected from gentoo penguins, macaroni penguins, gray-headed albatrosses, black-browed albatrosses and Antarctic fur seals on Bird Island in the South Georgian archipelago during the austral summer of 1996 and 1998. In 1996, S. havana, S. typhimurium and S. enteritidis were isolated from 7% of gentoo penguins and 4% of fur seals. In 1998, however, 22% of fur seals were found to be infected with S. havana, S. enteritidis and S. newport. All isolates, except one, showed identical pulsed-field gel electrophoresis-patterns within each serotype, irrespective of sampling year and animal reservoir. No significant antibiotic resistance was found. The very low heterogeneity in the salmonella isolates found could either indicate a high genetic adaptation of the bacteria to the environment or a recent introduction of salmonella into the area.
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