The Effect of Dietary Restriction on PhIP-Induced Mutation in the Distal Colon and B[a]P- and ENU-Induced Mutation in the Liver of the Rat
Bibliographic record
Abstract
A reduction in dietary intake has been shown to significantly increase the lifespan of rodents, lower the incidence of tumors, and reduce DNA damage. The objective of this study was to determine whether dietary restriction (DR) reduced the frequency of mutation induced by two environmentally relevant metabolically activated mutagens and one direct-acting mutagen in the lacI transgene of male and female Big BlueR rats. Both male and female rats were maintained on either an ad libitum (AL) or a 40%-reduced diet for 22 wk. The mutagenicity of a 100-mg/kg intraperitoneal injection with 2-amino-1-methyl-6-pheny-imidazo[4,5-b] pyridine (PhIP), benzo[a]pyrene (B[a]P), and N-ethyl-N- nitrosourea (ENU) was determined in the colon or liver. The results indicated that DR did not significantly alter the PhIP-induced mutant frequency in male or female colons. DR completely prevented mutagenicity induced by B[a]P in the female liver (2.6 +/- 0.6 10(-5) vs 10.9 +/- 5.8 10(-5) in AL females), yet increased the induced frequency in male livers (16.3 +/- 3.7 10(-5) vs 10.6 +/- 1.5 10(-5) in AL male livers). Although there was no difference in mutation frequency in the liver between AL and DR females treated with ENU, there was approximately a 40% decrease in induced frequency in DR males compared with AL males. These results indicate that a reduction in dietary intake has no preventive effect against PhIP-induced mutation in the colon, but has sex-dependent protective effects against B[a]P- and ENU-induced mutation in the liver.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.001 |
| 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".