IC50 of NaNO
. L. (V.) braziliensis isolated from antimony-refractory patients were more resistant to the NO-generating compound NaNO2 than L. (V.) braziliensis isolated from responsive patients. Eight isolates each from refractory or responsive subject were tested for susceptibility or resistance to NaNO2 using the MTT assay. Lines mean median (* = p = 0.038, Mann-Whitney test). Lb = L. (V.) braziliensis.