PubMed · 3607123
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
A Amdisen. 1987. Pearson's correlation coefficient, p-value, and lithium therapy.. https://doi.org/10.1016/0006-3223(87)90094-1
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Increased numbers of platelet-derived growth factor beta receptors betaPPDGFRs) on neovascular endothelial cells is a common occurrence in several pathological conditions including wound healing, inflammation, and glioma tumorigenesis. Here we sought to test the biological significance of this by determining whether expression of wild-type betaPDGFR by normal aortic endothelial cells affected the expression of the vascular endothelial growth factor (VEGF), a critical angiogenesis regulator and mitogen for such cells. The results showed that PDGF could increase transcription and secretion of VEGF by betaPDGFR-expressing endothelial cells. Moreover, we further demonstrated a requirement for the activation of phosphatidylinositol 3-kinase (PI3K) in this response by using chemical inhibitors of PI3K, mutant PDGFR, and dominant-negative PI3K. These studies suggest a novel mechanism by which PDGF induces VEGF expression in endothelial cells, define VEGF as a downstream target for PI3K, and invoke a role for PI3K in angiogenesis.
In this paper we discuss how to make meaningful use of a dose response study. It is argued that concepts like the minimal effective dose are not clinically meaningful and that the purpose of a dose response study should be to identify the drug potency in relation to a known active control. We also discuss various ways of carrying out the analysis.
Different pteridine derivatives were investigated for their inhibitory action on xanthine oxidase. From 27 investigated compounds, 13 showed concentration-dependent inhibition of the enzyme. Concentrations necessary for 50% inhibition ranged from <0.1 up to >100 microM. Different types of inhibition were found concerning xanthine and pterin as substrates: competitive, noncompetitive and mixed type. Out of 18 aromatic compounds tested, 12 were inhibitors. Only one out of nine reduced derivatives served as inhibitor. A simple regression model was used to specify the structural requirements for a pteridine to be an inhibitor. The most characteristic features of an inhibitor are aromaticity and no substitution at position 7 of the pteridine ring.