TNF and depressive symptom measurement: There is evidence that patients with diabetes or depression have significantly increased levels of oxidative stress markers including malondialdehyde (MDA), F2-isoprostanes, and 8-OH 2-deoxyguanosine (8-OHdG), as well as proinflammatory cytokines, such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α).