| 1. |
- Huang, Z. L., et al.
(author)
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Novel heterocycle-based organic molecules with two-photon induced blue fluorescent emission
- 2003
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In: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 13:4, s. 708-711
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Journal article (peer-reviewed)abstract
- Two-photon absorption and two-photon induced blue emission characteristics of a series of heterocycle-based organic molecules are investigated experimentally and by quantum-chemical computations. The molecules consist of a typical A-pi-A' structure, where heterocycle, styryl and formyl groups are employed as A, pi-conjugated and A' moieties, respectively. Experimental results indicate that significant enhancements in the blue emission efficiency and two-photon absorption cross-sections can be achieved by replacing S and O atoms with an N atom in the heterocycle acceptor moiety, which is also supported by the quantum-chemical computations. Additionally, larger two-photon absorption cross-sections can be obtained by choosing appropriate solvents, as indicated by the computations.
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| 2. |
- Lundberg, G, et al.
(author)
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A rat model for severe limb ischemia at rest
- 2003
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In: European surgical research. Europaische chirurgische Forschung. Recherches chirurgicales europeennes. - : S. Karger AG. - 0014-312X. ; 35:5, s. 430-438
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Journal article (peer-reviewed)abstract
- We sought an animal model able to discriminate metabolic and angiogenic processes in limb ischemia. For that we modified and evaluated a rat model of severe unilateral limb ischemia at rest. A two-stage surgical procedure entailing left femoral artery ligation preceded by interruption of collateral vessels originating from the infra-renal aorta and left iliac arteries was performed in Sprague-Dawley rats. The model was evaluated for up to 8 weeks with a transit-time flow meter, a laser Doppler perfusion imager, microspheres, arteriography and histology. It was found to be well tolerated with low mortality and perfusion in the foot skin was reduced up to 8 weeks, while collaterals were visible after 2 weeks. Histologic signs of ischemia were seen for up to 4 weeks. This rat model of severe limb ischemia at rest lasts up to 8 weeks and seems well suited for longitudinal studies of the pathophysiology of limb ischemia and healing mechanisms like angio- and arteriogenesis.
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| 3. |
- Svensson, Mik, et al.
(author)
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Roles of the plasminogen activator streptokinase and the plasminogen-associated M protein in an experimental model for streptococcal impetigo
- 2002
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In: Microbiology. - 1465-2080. ; 148:12, s. 3933-3945
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Journal article (peer-reviewed)abstract
- Primary infection by group A streptococci (GAS) takes place at either the throat or skin of the human host, often leading to pharyngitis or impetigo, respectively. Many GAS strains differ in their preference for throat and skin tissue sites. Previous epidemiological findings show that many of the strains displaying strong tropism for the skin have a high-affinity binding site for plasminogen, located within M protein (PAM), a prominent surface fibril. Plasminogen bound by PAM interacts with streptokinase, a plasminogen activator secreted by GAS, to yield bacterial-bound plasmin activity. In this study, PAM and streptokinase were tested for their roles in infection using an experimental model that closely mimics human impetigo. Inactivation of genes encoding either PAM or streptokinase led to a partial, but significant, loss of virulence in vivo, as measured by net growth of the bacteria and pathological alterations. The relative loss in virulence in vivo was greater for the streptokinase mutant than for the PAM mutant. However, the PAM mutant, but not the streptokinase mutant, displayed a partial loss in resistance to phagocytosis in vitro. The combined experimental and epidemiological data provide evidence that PAM and streptokinase play a key role in mediating skin-specific infection by GAS. In addition, secreted cysteine proteinase activity due to SpeB leads to degradation of streptokinase in stationary phase broth cultures. Since SpeB is also a determinant of tissue-specific GAS infection at the skin, direct interactions between these two proteolytic pathways may constitute an important pathogenic mechanism. An integrated model for superficial infection at the skin is presented.
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