Oxidative stress, free radical-mediated diseases, and biomarkers. Abbreviations: BPD: bronchopulmonary dysplasia, ROP: retinopathy of prematurity, NEC: necrotizing enterocolitis, IVH: intraventricular hemorrhage, PVL: periventricular leukomalacia, RDS: respiratory distress syndrome, PDA: patent ductus arteriosus, AGE: advanced glycated end product, AOPP: advanced oxidation protein products, TH: total hydroperoxide, IsoPs: isoprostanes, IsoFs: isofurans, NeuroPr: neuroprostanes, MDA: malondialdehyde, 4-HNE: 4-hydroxy-2-nonenal, SOD: superoxide dismutase, CAT: catalase, GPX: glutathione peroxidase, GSH: glutathione, GSSG: glutathione disulfide, NPBI: non protein-bound iron, 8-OHdG: 8-hydroxy-2’-deoxyguanosine, XO: xanthine oxidase, MPO: myeloperoxidase, TAC: total antioxidant capacity, TOS: total antioxidant status, OSI: oxidative stress index. Image created in BioRender.com.