Diagnosis of defects in oxidative muscle metabolism by non-invasive tissue oximetry.
The dynamics of oxygen delivery and utilization are examined in a variety of mitochondrial disorders during rest, exercise and post exercise. We used a non-invasive optical technique to measure the oxygen consumption in the exercising limb in normal subjects and 5 patients with cytochrome c oxidase deficiency. We also examined 6 patients with MELAS and MERRF syndrome. We measured near-infrared spectra of hemoglobin in the gastrocnemius muscle during treadmill exercise. Normal subjects demonstrated a sustained deoxygenation during exercise, indicating an efficient utilization of delivered oxygen. Patients with cytochrome c oxidase deficiency demonstrated consistent oxygenation during exercise indicating an under utilization of delivered oxygen. Patients with MELAS and MERRF syndrome showed similar under utilization of oxygen during exercise. Non-invasive tissue oximetry during exercise demonstrates specific abnormalities in a variety of mitochondrial disorders, indicating abnormal oxygen utilization, and will be a useful addition to the clinical investigation of such disorders.
Bank
W
W
Department of Neurology, University of Pennsylvania, Philadelphia 19104, USA.
Chance
B
B
D030401:Cytochrome-c Oxidase Deficiency; D006801:Humans; D017241:MELAS Syndrome / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D017243:MERRF Syndrome / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*
D010100:Oxygen