The mutagenic activity of select azo compounds in MutaMouse target tissues in vivo and primary hepatocytes in vitro
Bibliographic record
Abstract
The mutagenicity of Direct Black 38, Sudan I, and Para Red were evaluated in the in vivo MutaMouse assay and the in vitro MutaMouse primary hepatocyte (PH) assay. Direct Black 38 is an International Agency for Research on Cancer (IARC) Group 1 carcinogen and a prototypical benzidine-based azo compound that requires azo-reduction to yield a DNA-reactive metabolite. Sudan I and Para Red are structurally related azo compounds that have been detected as illegal contaminants in foods. Sudan I is an in vivo mutagen, and both it and Para Red are known to be mutagenic in vitro. Sudan I is oxidized by hepatic and/or bladder enzymes to yield a mutagenic metabolite, but little is known about Para Red. In the present study, Direct Black 38 elicited a significant mutagenic response in the bone marrow, glandular stomach, small intestine and colon in vivo, and in PHs in vitro. Sudan I elicited a weak positive response in the bone marrow and a marginally significant treatment effect in the bladder (p = 0.059); it did not elicit a significant response in PHs in vitro. Para Red elicited a positive response in the colon, as well as in PHs in vitro, albeit at a cytotoxic concentration. The findings are well aligned with the known mechanisms of action of Direct Black 38 and Sudan I; they suggest that intestinal azo-reduction plays an important role in the activation of Para Red. The MutaMouse pH results illustrate the ability of this assay to detect chemicals requiring azo-reduction; however, they also demonstrate a gap in applicability domain, as MutaMouse PHs elicit a negative response following exposure to Sudan I. Elucidation of the mechanisms underlying this gap will require further study.
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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) | 0.002 | 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".