Table of Contents
Washington University Experience | MUSCLE | Autophagic myopathy | 11K1 HCG (Case 11) COX 20X 3
11K series ---- Cytochrome c oxidase (COX) is a mitochondrial (Complex IV) stain in which key subunits of the COX enzyme are encoded by mitochondrial DNA. Type I fibers (which are highly oxidative) contain a high volume of mitochondria and stain dark brown. Type II fibers (glycolytic) have fewer mitochondria and stain light brown. Mitochondrial disease (i.e., mitochondrial myopathy) results in random completely colorless (COX-negative) fibers. In this case there are very rare fibers with completely absent staining. A single muscle fiber can have a mix of healthy and mutated mitochondria due to heteroplasmy. ---- 11K1 In this area there are dark and light brown stained fibers likely reflecting the fiber type grouping seen in the section of ATPase pH 9.4. (COX)
