Endothelial ultrastructural alterations of intramuscular capillaries in infantile mitochondrial cytopathies: “Mitochondrial angiopathy”
Bibliographic record
Abstract
Electron microscopy (EM) is a reliable method for diagnosing mitochondrial diseases in striated muscle biopsy in infancy. Ultrastructural alterations in mitochondria of myofibers are well documented, but there are few studies of endothelial involvement in intramuscular capillaries. Quadriceps femoris biopsies of five representative infants and toddlers, ages neonate to 3.5 years, were performed because of clinical and laboratory data consistent with mitochondrial disease without mitochondrial DNA (mtDNA) mutations and likely with nuclear DNA mutations. Pathological studies included histochemistry, EM, respiratory chain enzymatic assay and mtDNA sequencing and deletion/duplication analysis. EM demonstrated frequent and severe alterations of mitochondria in capillary endothelium. The most constant changes included: either too few or fragmented cristae; stacked and whorled cristae; paracrystallin structures that often were large and spheroid with stress fractures; closely apposed membranes of granular endoplasmic reticulum surrounding mitochondria with loss of the normal intervening layer of cytoplasm; long narrow, thin looped microvilli extending into the lumen; and thick microvilli containing large, abnormal mitochondria. We conclude that mitochondrial cytopathies in early life exhibit more severe ultrastructural alterations in the endothelium than in myofibers and that paracrystallin body structure differs, perhaps due to less rigid surrounding structures. This distribution may explain the frequent lack of prominent histochemical and biochemical abnormalities in muscle biopsies of young patients. Endothelial changes do not distinguish the genetic defects. Vascular involvement in brain contributes to cerebral lesions and neuronal death by impairment of molecular and nutrient transport and ischemia; endothelium in muscle may reflect similar changes.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".