Nitric oxide is an irreversible human diamine oxidase inhibitor
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Diamine oxidase (DAO) histamine-degradation rates are compromised in plasma of mastocytosis patients during severe mast cell activation events. Mast cell-liberated histamine induces the release of nitric oxide (NO) close to DAO extracellular storage sites. We hypothesized that NO inhibits DAO activity. Recombinant human DAO activity was measured after incubation with NO-releasing NONOates (R1R2N−(NO−)−N = O). Topaquinone reactivity was quantified by absorption measurements and by mass spectrometry. Several murine models of NO-production were assessed for DAO activity inhibition in vivo. Nitric oxide released from NONOates dose dependently and irreversibly inhibited DAO activity. The NO scavengers Trolox (Vitamin E derivative) and 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (C-PTIO), the reversible DAO inhibitors diminazene and ciproxifan, the substrates histamine (EC50 = 32 µM) and putrescine (EC50 = 39 µM), heparin whole blood and plasma protected DAO from inhibition. Nitric oxide reduced the reactivity of topaquinone to phenylhydrazine by 90%. None of the NO producing in vivo models showed DAO inhibition in plasma or tissue. Nitric oxide is a potent irreversible DAO inhibitor in vitro representing the first discovered natural inhibitor for this enzyme. Endogenous mouse DAO inhibition in vivo could not be demonstrated. The true nature of human DAO activity inhibition during severe mastocytosis events remains unknown.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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 it