Effects of gene transfer on cell death in primary neuronal cultures. Effects of gene transfer of constitutively active Akt1 (cAkt1), constitutively active Akt3 (cAkt3), and dominant-negative Akt (AktDN) on neuronal death as measured by lactate dehydrogenase (LDH) release. Cultured mixed neurons were transfected with vectors containing cAkt1, cAkt3, and AktDN; cultures transfected with GFP vectors or treated with vehicle solution served as controls. Cultures were subjected to 6 hours of oxygen glucose deprivation (OGD) 2 days after transfection. LHD release was measured at 16 hours after OGD. All data after OGD were normalized to the values of control, nonOGD samples transfected with the corresponding vectors. n=18 to 24/group. *, **, P<0.05, 0.001, respectively, versus GFP control vector receiving OGD treatment. Φ, ΦΦ, P<0.05, 0.01, respectively, between the two indicated groups.