Cross-sectional areas of diaphragm muscle. Cross-sections of diaphragm muscle from biopsy specimens of a representative organ donor subject ((a), (c), (e)) and from a control ((b), (d), (f)). (a) and (b) Muscle fibers in the organ donor subject are in general smaller than those in the control diaphragm. No inflammatory infiltrate or necrosis is seen. Stained with hematoxylin and eosin. (c) and (d) Stained with antibody specific for slow myosin, heavy chain. (e) and (f) Stained with antibody specific for fast myosin, heavy chain. In (c) to (f), fibers reacting with the antibody appear orange-red, whereas fibers not reacting with the antibody appear black; open circle, slow-twitch fibers; open square, fast-twitch fibers. In addition, all fibers in each section are outlined by an antibody reactive to laminin. Reproduced with permission from . Copyright © 2008 Massachusetts Medical Society. All rights reserved.