Different Contribution of Endothelial Nitric Oxide in the Relaxation of Human Coronary Arteries of Ischemic and Dilated Cardiomyopathic Hearts
Bibliographic record
Abstract
Coronary artery disease and congestive heart failure (CHF) have been associated with a reduction in nitric oxide (NO) release or bioavailability from the vascular endothelium. The objectives of this study were to compare the role of NO in human coronary vessels isolated from nonischemic dilated (DCM) (n = 10) and ischemic (ICM) (n = 12) cardiomyopathic hearts. Segments were mounted on a wire myograph to record changes in isometric tension. All experiments were performed in the presence of indomethacin (10 microM). Contractions induced by angiotensin II (0.1 microM) or a depolarizing physiologic solution containing 40 mM KCl, were of similar amplitude in DCM and ICM. In vessels precontracted with angiotensin II, acetylcholine (1 microM) caused an endothelium-dependent relaxation of rings from DCM but a paradoxical contraction of rings from ICM; NO synthase inhibition with Nomega-nitro-L-arginine (L-NNA, 100 microM) did not affect acetylcholine-induced relaxation or contraction of DCM or ICM vessels, respectively. By contrast, substance P (0.1 microM) induced an endothelium-dependent relaxation in both groups of vessels; this relaxation was prevented (p < 0.05) by L-NNA in vessels from ICM hearts but only reduced (p < 0.05) by L-NNA in vessels from DCM hearts. In depolarized conditions, acetylcholine contracted (p < 0.05) whereas substance P induced a complete relaxation (p < 0.05) of vessels from both groups: substance P-induced relaxation was abolished (p < 0.05) by L-NNA. Our data suggest that in the presence of indomethacin, NO does not contribute to acetylcholine-induced relaxation of human epicardial coronary arteries isolated from DCM hearts. Furthermore, whereas NO and a secondary endothelium-derived relaxing factor sensitive to high K+ contribute to substance P-induced relaxation of rings from DCM hearts, only NO is involved in ICM hearts.
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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".