Table 2. Classification of muscle fibres with mitochondrial alterations according to histochemical quantification.
| fibre type | mitochondrial alteration | SDH activity (%) | COX activity (%) | SDH/COX | N |
|---|---|---|---|---|---|
| I | normal | 56.9–143.9 | 53.1–161.1 | 0.6–1.5 | 477 |
| RRF/COX+ | >143.9 | >53.1 | 0.6–1.5 | 48 | |
| RRF/COXdef | >143.9 | 53.1-161.1 | >1.5 | 119 | |
| RRF/COX− | >143.9 | <53.1 | 322 | ||
| COX− | 56.9–143.9 | <53.1 | 168 | ||
| II | Normal | 55.1–161.1 | 47.5–152.9 | 0.6–1.7 | 365 |
| RRF/COX+ | >161.1 | >47.5 | 0.6–1.7 | 49 | |
| RRF/COXdef | >161.1 | 47.5–152.9 | >1.7 | 56 | |
| RRF/COX− | >161.1 | <47.5 | 150 | ||
| COX− | 55.1–161.1 | <47.5 | 223 |
RRF: ragged red fibres; COX+: normal COX activity; COXdef: partial COX deficiency; COX−: total COX deficiency; N: number of fibres.