- Combined inhibition of indoleamine 2,3-dioxygenase and nitric oxide synthase modulates neurotoxin release by interferon-gamma-activated macrophages. Chiarugi, A., Dello Sbarba, P., Paccagnini, A., Donnini, S., Filippi, S., Moroni, F. J. Leukoc. Biol. (2000)