SOD1 and susceptibility to pneumonia measurement: We recently reported that mice with a double knockout (DKO) of Sod1 encoding superoxide dismutase 1 (SOD1) and Akr1a encoding aldehyde reductase survived more than one year when supplemented with ascorbic acid (Asc) (1.5 mg/ml in drinking water), and that the withdrawal of Asc resulted in premature death in only two weeks due to oxidative damage-associated pneumonia.