PMC3570393_01
A-D: Skeletal muscle biopsy showing one ragged red fiber with histological methods (A-B: H&E, 10X ; B: GT, 40X). Histochemical reactions for COX (C, 10X) and COX-SDH (D, 10X) in cross serial sections show lack of COX activity in several skeletal muscle fibers (C), many of which also show increased SDH activity (D).E-H: Axial T2-weighted cerebral MRI sequences showing a cortico-subcortical fronto-parietal hyperintensity with restricted diffusion (not shown) consistent with acute ischaemic lesion and bilateral old ischaemic lesions in the right occipital and left temporal lobe.
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F1
Other bilateral focal hyperintensities, mostly in the posterior circulation territory (cerebellar bilateral, left temporo-occipital and frontal) consistent with stabilized ischaemic lesions, were also found (Figure 1). CT scan performed in the acute phase was unmodified in comparison to the previous ones. Cerebral MRI at day 3 demonstrated a small cortical-subcortical left temporo-occipital lesion with DWI restriction (Figure 1). Histochemically, several fibers were Cytochrome c Oxidase (COX)-negative, many of these fibers were also intensely SDH-positive (Figure 1).
Molecular analysis of muscle-derived mitochondrial DNA. Southern blot (A) and PCR assay (B) showing the accumulation of multiple deletions in patient's tissue.
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F2
Southern blot analysis of muscle mtDNA revealed the presence of several bands compatible with mtDNA multiple deletions (Figure 2).