Reactive oxygen species production and mitochondrial dysfunction in white blood cells are not valid biomarkers of ageing in the very old. oleh Laura Wiley, Deepthi Ashok, Carmen Martin-Ruiz, Duncan C S Talbot, Joanna Collerton, Andrew Kingston, Karen Davies, Patrick F Chinnery, Michael Catt, Carol Jagger, Thomas B L Kirkwood, Thomas von Zglinicki