Prednisone prevents atrial fibrillation promotion by atrial tachycardia remodeling in dogs
Bibliographic record
Abstract
BACKGROUND: There is evidence suggesting involvement of oxidative stress, inflammation, and calcineurin/nuclear factor of activated T cell pathways in atrial fibrillation. This study evaluated the efficacy of anti-inflammatory and calcineurin-inhibitory drugs on promotion of atrial fibrillation by atrial tachycardia-induced remodeling in dogs. METHODS AND RESULTS: Dogs were subjected to atrial tachypacing at 400 bpm in the absence and presence of treatment with prednisone (15 or 50 mg/day) or ibuprofen (anti-inflammatory) or cyclosporine-A (calcineurin inhibitor). Serial closed-chest electrophysiological studies were performed in each dog at baseline and 2, 4, and 7 days after tachypacing onset. A final open-chest study was performed on day 8. Serum C-reactive protein was measured by ELISA and nitric oxide synthase by Western blotting. The mean duration of induced atrial fibrillation was markedly increased by tachypacing alone, from 26+/-8 to 962+/-317 s (p<0.01), and the atrial effective refractory period was decreased from 117+/-4 to 73+/-7 ms (p<0.001; cycle-length 300 ms). Tachypacing-induced effective refractory period shortening and atrial fibrillation promotion were unaffected by ibuprofen or cyclosporine-A; however, both doses of prednisone suppressed tachypacing-remodeling effects (atrial fibrillation duration to 96+/-60 s and 28+/-11 s at higher and lower doses, respectively; effective refractory period to 101+/-6 ms for higher-dose and 105+/-3 ms for lower-dose group). In addition, prednisone (but not ibuprofen or cyclosporine) significantly decreased C-reactive protein concentrations and attenuated the increase in endothelial nitric oxide synthase expression caused by atrial tachypacing. CONCLUSIONS: Prednisone prevents the electrophysiological and atrial fibrillation-promoting effects of atrial tachycardia-remodeling, possibly by an anti-inflammatory action, whereas the less potent anti-inflammatory ibuprofen and the calcineurin inhibitor cyclosporine-A are without effect.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".