Production of Lipid‐Derived Free Radicals in L1210 Murine Leukemia Cells Is an Early Oxidative Event in the Photodynamic Action of Photofrin

Photofrin photosensitization initiates a sequence of oxidative events that begins with singlet oxygen formation and ultimately leads to cell death. We hypothesize that membrane lipid-derived free radical formation is an early event in this process. In the presence of iron and ascorbate, lipid free radicals are generated during cellular photosensitization of L1210 cells as detected by electron paramagnetic resonance spin-trapping techniques....