Figure 3.
A. Maximum specific force (force normalized per cross-sectional area) in single type-identified DIAm fibers expressing MyHC isoforms slow and 2A from patients with (black bars) and without (white bars) chronic obstructive pulmonary disease (COPD). Specific force is reduced across DIAm fiber types in COPD patients. B. In single DIAm fibers, MyHC content per half-sarcomere was determined from the volume of a half-sarcomere and electrophoretically-determined MyHC concentration. MyHC content per half-sarcomere is reduced across DIAm fiber types in COPD patients. C. Maximum specific force normalized by the MyHC content per half-sarcomere no longer differs across fiber types in the DIAm of patients with and without COPD. Data are mean ± SE; *p < 0.05, different from non-COPD group. Data from Ottenheijm et al. (2005).