Fig. 4— a) Nitrate/nitrite, b) methyl guanidine (MG), c) tumour necrosis factor (TNF)-α, and d) interleukin (IL)-1β in lung perfusate. Ischaemia/reperfusion (I/R) significantly elevated these factors. Post-treatment with nicotinamide (NCA) attenuated the effects of I/R on the nitric oxide metabolites, hydroxyl radical and pro-inflammatory cytokines. □: vehicle (n = 10); ▒: I/R alone (n = 10); ░: I/R and NCA (n = 10). *: p<0.05 versus vehicle group; #: p<0.05 versus I/R group.