Surfactant as an Airway Smooth Muscle Relaxant
Bibliographic record
Abstract
A variety of clinical and experimental evidence indicates that surfactant may be important in the pathogenesis and treatment of asthma. The purpose of this study was to determine the pharmacologic effect of pulmonary surfactant and its major lipid and protein constituents on bronchial smooth muscle. First-generation bronchi from male Sprague-Dawley rats were contracted with methacholine and exposed to two kinds of surfactant: whole rat surfactant and two bovine surfactant extracts in clinical use. The latter lack the hydrophilic surfactant-associated proteins (SP)-A and SP-D. All the surfactants relaxed the rat bronchi in a concentration-dependent manner; however, whole rat surfactant was more potent than the bovine extracts. Both surfactant lipids and SP-A contributed to the bronchial relaxation. The relaxation response produced by the highest concentration (0.5 mg/ml) of whole rat surfactant was equivalent to that caused by substance P (5 microM) and approximately half of that caused by 1 microM isoproterenol. The relaxation response was epithelium-dependent and blocked by indomethacin but not by N-omega-nitro-L-arginine methyl ester. We conclude that surfactant can relax airway smooth muscle directly via a prostanoid-mediated, epithelium-dependent process that does not involve nitric oxide synthase.
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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".