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- Dixelius, J, et al.
(author)
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Laminin-1 promotes angiogenesis in synergy with fibroblast growth factor by distinct regulation of the gene and protein expression profile in endothelial cells
- 2004
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In: Journal of Biological Chemistry. - 1083-351X. ; 279:22, s. 23766-23772
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Journal article (peer-reviewed)abstract
- Laminins are widely distributed extracellular matrix proteins. Certain laminin isoforms are predominant in vascular basement membranes and may be critical in maintaining the stability of the mature vessel. On the other hand, formation of new vessels during angiogenesis requires degradation of the basement membrane, exposing the endothelial cells to other laminin isoforms in the surrounding extracellular matrix. We studied the effects of laminin-1 (LN-1) in different in vitro and in vivo models for angiogenesis. LN-1 induced angiogenesis in the chicken chorioallantoic membrane to the same extent as fibroblast growth factor-2 (FGF-2), and vascular development in embryoid bodies was stimulated in a synergistic manner by FGF-2 and LN-1. LN-1 promoted differentiation of endothelial cells in three-dimensional collagen gels, both in the absence and presence of FGF-2. Formation of tubular structures induced by LN-1 was accompanied by increased expression of Jagged-1, a marker of endothelial differentiation, and increased levels of FGF-2 and FGFR-1 transcripts. LN-1 did not regulate signal transduction pathways known to operate down stream of FGF-2. Thus, phosphorylation of ERK was detected in FGF-2- but not in LN-1-treated cells. Taken together, this suggests that laminins may play a fundamental role in angiogenesis by directly affecting gene and protein expression profiles in endothelial cells.
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- Nyberg, S, et al.
(author)
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Assessing camouflage methods using textural features
- 2001
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In: Optical Engineering. - 0091-3286 .- 1560-2303. ; 40:9, s. 1869-1876
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Journal article (peer-reviewed)abstract
- Developments in the area of signature suppression make it progressively more difficult to recognize targets. The emphasis has been on the reduction of distinct features, like hot spots in the infrared band. Thus, to obtain a low false alarm rate, threat sensors have to utilize more information, i.e., spatial and spectral properties. The purpose of our work is to develop a general tool for camouflage assessment. The approach proposed applies texture descriptors to quantify the similarity between different parts of an image. In addition, other descriptors are used to distinguish man-made object characteristics. The selection of an appropriate set of features is discussed. The assumption is that an area containing observable targets has different statistics than other areas. Statistical properties along with detected target specific features have to be combined with methods used in data fusion. An experiment with a dataset of 44 reference images has been carried out, using a recently developed computer program called Terrtex. High correlation with perception experiments is achieved using only one or two texture features. The importance of a careful selection of background area size is finally discussed. (C) 2001 Society of Photo-optical instrumentation Engineers.
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