Figure 4.

Growth capacity measurement. Six and 26 months represent 24 and 25 cybrids per age group, respectively. Cells were grown in glucose-containing DMEM for 24 h, then in glucose medium (A) or in galactose medium (B) for another 72 h. Doubling times were calculated as: 72 h × Log (2)/[Log (total cell number at the end)-Log (total cell number when media were changed)]. Three determinations were made for each cybrid. Growth index was calculated as the ratio of doubling time in galactose-containing medium to that in glucose medium (C).