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- Title
Muscle fatigue, lactate, and pyruvate in mitochondrial myopathy with progressive external ophthalmoplegia.
- Authors
Dengler, Reinhard; Wohlfarth, Kai; Zierz, Stephan; Jöbges, Michael; Schubert, Margot; Dengler, R; Wohlfarth, K; Zierz, S; Jobges, M; Schubert, M
- Abstract
We studied muscle fatigue and serum lactate and pyruvate levels in 20 patients with mitochondrial myopathy with progressive external ophthalmoplegia (PEO). Fatigue was assessed in the adductor pollicis muscle (AP) using a low-intensity exercise protocol (20 min). Forces (TFs) and relaxation times of ulnar nerve evoked twitches, compound muscle action potentials (CMAPs), and maximal voluntary contractions (MVCs) were monitored. Serum lactate and pyruvate levels were independently measured at rest and after exercise on a bicycle (15 min, 30 W). Most patients showed abnormal fatigue of the AP with a reduction of TFs and MVCs and normal CMAPs. The reduced TFs were significantly correlated with lactate levels at rest (r= - 0.60, P<0.05) and less so with those after exercise (r=- 0.47,P<0.05). Pyruvate levels revealed a similar correlation although they were widely scattered. We conclude that abnormal fatigue in PEO is metabolic, is localized beyond the muscle fiber membrane, and involves the electrome-chanical coupling and the contractile apparatus. Serum lactate levels at rest are good predictors of fatigue in PEO.
- Subjects
ACTION potentials; CARBOXYLIC acids; COMPARATIVE studies; EXERCISE tests; LACTATES; LACTIC acid; RESEARCH methodology; MEDICAL cooperation; MUSCLE contraction; MUSCLE diseases; RESEARCH; EVALUATION research; MITOCHONDRIAL myopathy; MUSCLE fatigue; CHRONIC progressive external opthalmoplegia; DISEASE complications
- Publication
Muscle & Nerve, 1996, Vol 19, Issue 4, p456
- ISSN
0148-639X
- Publication type
journal article
- DOI
10.1002/(SICI)1097-4598(199604)19:4<456::AID-MUS5>3.0.CO;2-B