Tadalafil‐sensitive impairment in muscle blood flow during exercise in Duchenne Muscular Dystrophy
Bibliographic record
Abstract
Out‐of‐frame mutations in the dystrophin gene cause Duchenne muscular dystrophy (DMD)—a devastating X‐linked muscle wasting disease for which there is no treatment other than corticosteroids. In DMD, loss of the cytoskeletal protein dystrophin impairs sarcoelmmal targeting of nNOS, which is the main source of skeletal muscle‐derived nitric oxide (NO). We previously showed that loss of nNOS impairs the normal exercise‐induced attenuation of reflex vasoconstriction in dystrophic skeletal muscle, thus implicating a putative vascular component to the pathogenesis of DMD. Here we present data on a second phenotype, that muscle blood flow (BF, measured by Doppler ultrasound of the brachial artery) fails to increase normally during mild rhythmic handgrip exercise in 6 boys with DMD (7–13 years of age) compared with 8 age‐matched male controls (Ctrls): ΔBF:+13±5% vs. +81±10%, respectively (p<.05). Moreover, we show that the phosphodiesterase 5 inhibitor Tadalafil, restores active hyperemia in boys with DMD in a dose‐dependent manner: 0.5 mg/kg, +56±13%; 1.0 mg/kg, +72+18% These data significantly advance the vascular hypothesis of DMD and implicate PDE5 inhibition as a putative therapeutic treatment option. Support: Parent Project Muscular Dystrophy, Heart and Stroke Foundation of Canada (MN)
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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".