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M Jeltsch A Kaipainen V Joukov X Meng M Lakso H Rauvala M Swartz D Fukumura RK Jain K Alitalo 《Canadian Metallurgical Quarterly》1997,276(5317):1423-1425
No growth factors specific for the lymphatic vascular system have yet been described. Vascular endothelial growth factor (VEGF) regulates vascular permeability and angiogenesis, but does not promote lymphangiogenesis. Overexpression of VEGF-C, a ligand of the VEGF receptors VEGFR-3 and VEGFR-2, in the skin of transgenic mice resulted in lymphatic, but not vascular, endothelial proliferation and vessel enlargement. Thus, VEGF-C induces selective hyperplasia of the lymphatic vasculature, which is involved in the draining of interstitial fluid and in immune function, inflammation, and tumor metastasis. VEGF-C may play a role in disorders involving the lymphatic system and may be of potential use in therapeutic lymphangiogenesis. 相似文献
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Taicatoxin, isolated from the venom of the Australian taipan snake Oxyuranus scutellatus, has been previously regarded as a specific blocker of high threshold Ca2+ channels in heart. Here we show that taicatoxin (in contrast to a range of other Ca2+ channel blockers) interacts with apamin-sensitive, small conductance, Ca2+-activated potassium channels on both chromaffin cells and in the brain. Taicatoxin displays high affinity recognition of 125I-apamin acceptor-binding sites, present on rat synaptosomal membranes (Ki = 1.45 +/- 0.22 nM) and also specifically blocks affinity-labeling of a 33-kDa 125I-apamin-binding polypeptide on rat brain membranes. Taicatoxin (50 nM) completely blocks apamin-sensitive after-hyperpolarizing slow tail K+ currents generated in rat chromaffin cells (mean block 97 +/- 3%, n = 12) while only partially reducing total voltage-dependent Ca2+ currents (mean block 12 +/- 4%, n = 6). In view of these findings, the use of taicatoxin as a specific ligand for Ca2+ channels should now be reconsidered. 相似文献
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In vitro experiments that characterize DNA-protein interactions by artificial selection, such as SELEX,are often performed with the assumption that the experimental conditions are equivalent to natural ones. To test whether SELEX gives natural results, we compared sequence logos composed from naturally occurring leucine-responsive regulatory protein (Lrp) binding sites with those composed from SELEX-generated binding sites. The sequence logos were significantly different, indicating that the binding conditions are disparate. A likely explanation is that the SELEX experiment selected for a dimeric or trimeric Lrp complex bound to DNA. In contrast, natural sites appear to be bound by a monomer. This discrepancy suggests that in vitro selections do not necessarily give binding site sets comparable with the natural binding sites. 相似文献
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