Environmental exposure to polychlorinated biphenyls and placental CYP1A1 activity in Inuit women from northern Québec.
Bibliographic record
Abstract
Some polychlorinated biphenyl (PCB) congeners are CYP1A1 inducers, and induction of this enzyme in the placenta has been linked to adverse effects on fetal development. The objective of this study was to determine if the body burden of PCBs is related to placental CYP1A1 activity in Inuit women from Nunavik (northern Québec), a population highly exposed to organochlorines. Placenta and cord blood samples were obtained from 35 Inuit women and 30 women from a southern Québec community exposed to background levels of organochlorines. We measured PCB concentrations in all cord plasma samples and in a subset of placenta samples from the Nunavik group and assessed CYP1A1 activity (ethoxyresorufin-O-deethylase; EROD) in placental microsomes from all participants. Concentrations of PCBs in cord plasma were strongly correlated to those in placenta (Pearson's r) = 0.77-0.97, p < 0.001) and were on average 4-fold higher in Inuit women than in southern Québec women [for PCB 153, the geometric means (geometric SDs) were 83.3 (1.9) ng/g lipid vs. 16.9 (1.6) ng/g lipid, respectively]. Despite this difference in PCB body burden, both study groups had similar EROD activities when data were stratified according to tobacco smoking. Although simple correlation analysis first showed that placental EROD activity was correlated with PCB 153 plasma concentration in the Nunavik group, a multivariate analysis failed to demonstrate a significant contribution of PCBs to EROD activity when tobacco smoking was included in the analysis. We conclude that dietary exposure to PCBs in Inuit women from Nunavik does not significantly influence EROD activity in the placenta, implicating tobacco smoking as the major modulating factor.
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How this classification was reachedexpand
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.022 | 0.002 |
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; both teacher heads agree on what is shown here.
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".