Endothelial nitric oxide synthase activation by tumor necrosis factor alpha through neutral sphingomyelinase 2, sphingosine kinase 1, and sphingosine 1 phosphate receptors: a novel pathway relevant to the pathophysiology of endothelium - De Palma,C.; Meacci,E.; Perrotta,C.; Bruni,P.; Clementi,E. (Arterioscler Thromb Vasc Biol, 2006)