MDH2 and amyotrophic lateral sclerosis: The activity of mitochondrial malate dehydrogenase (mMDH) increased in the ALS I and ALS I SWIM groups (4.685 ± 0.20 and 3.904 ± 0.17 μmol/min/mg of protein, respectively) vs. the ALS 0 group (3.265 ± 0.11 μmol/min/mg of protein) and corresponding WT group of mice.