Tetrahydrobiopterin attenuates cholesterol induced coronary hyperreactivity to endothelin
Bibliographic record
Abstract
The vascular endothelium has emerged as a critical determinant of cardiovascular health and disease. Through the release of endothelium derived contracting and relaxing factors, the endothelium modulates vascular tone/reactivity acutely, and in the long term influences the process of vascular remodelling and mitogenesis.1 Hypercholesterolaemia is an important risk factor for coronary endothelial dysfunction. Although a variety of mechanisms have been proposed to link raised cholesterol to diminished endothelial function, recent studies suggest that hypercholesterolaemia may impair vascular function through augmenting the actions of the potent vasoactive peptide endothelin-1.2 Endothelin-1 elicits potent and protracted vasoconstriction; this effect is mediated directly via interaction with endothelin-A and endothelin-B receptors and indirectly via quenching of nitric oxide. Diminished production/availability of nitric oxide is a universal finding in patients with cardiovascular disease. Tetrahydrobiopterin (BH4) is a cofactor for various enzymatic processes and has been implicated in the pathogenesis of hyperphenylalaninaemia, neurological disorders, Alzheimer's disease, depression, Parkinson's disease, autism, and recently cardiovascular pathology and endothelial dysfunction.3 The balance of published information suggests that in the endothelial cell, BH4 is a critical cofactor for nitric oxide synthase activation, and hence nitric oxide production is dependent upon the presence of adequate amounts of this cofactor. BH4 exerts this action through serving as an electron donor for the hydroxylation of l-arginine. Diminished concentrations of this cofactor, as observed in states of cardiovascular disease, led to an uncoupling of endothelial nitric oxide synthase with diminished nitric oxide and exaggerated …
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".