Figure 3From: Elevated serum fibroblast growth factor 21 levels correlate with immune recovery but not mitochondrial dysfunction in HIV infectionCOX histochemistry. Example of mitochondrial COX/SDH (cytochrome c oxidase/succinate dehydrogenase) histochemistry on lower limb skeletal muscle biopsy of an anti-retroviral treated HIV-infected patient. Normal (COX positive) fibres stain brown, whereas COX deficient fibres counterstain blue due to preserved SDH activity.Back to article page