Semi-quantitative evaluation of staining for AP activity of LPS-stimulated vs. non stimulated endothelial cells, a, and TNFα-stimulated vs. non-stimulated mesangium cells, b. Columns represent arithmetic means of ratios expressed as indexes, i.e. relative number of positive cells, from stimulated (solid column) vs. control cultures (open columns). It is shown that significantly higher numbers of cells stain positive for AP in stimulated vs. non-stimulated cultures (*P ≤ 0.05; Wilcoxon). n = number of endothelial or mesangial cell cultures per group. Bars represent standard deviation.