Congenital fiber-type disproportion presenting with type II respiratory failure after delivery: A case report

Figure 5 Biopsy of the left biceps brachia (100 ×). A: Hematoxylin and eosin staining: muscle fiber size differed with a dominant type I muscle fiber atrophy; B: Adenosine triphosphate staining (pH, 4.3): type I muscle fiber enzyme activity was well preserved and seen as dark stains; unstained Type II muscle fiber demonstrated a loss of enzyme activity; C: Adenosine triphosphate staining (pH, 10.4): Enzyme activity of type I muscle fiber was partially lost, which can be seen as light stains; type II muscle fiber enzyme activity was well preserved and can be seen as dark stains. Panel A, B, C revealed that the diameters of type I muscle fibers were < type II muscle fibers.