Detection of Endocrine-Disrupting Chemicals in Samples of Second Trimester Human Amniotic Fluid
Bibliographic record
Abstract
Man-made chemicals that have been shown to modulate endocrine function in animal models, so-called "endocrine disrupters", are suspected to play a role in the development of male reproductive tract abnormalities and neurobehaviroal deficits in children. However in utero exposure to environmental contaminants has not been documented previously. The present study was performed to test our hypothesis that man-made chemicals can be quantified in human amniotic fluid during the second trimester. Gas chromatographic/mass spectrometric (GC/MS) analysis was performed on amniotic fluid samples (n=53) from women (n=51) undergoing routine amniocentesis with a mean (+/- SEM) age of 36.5 +/- 0.5 years and between 15 and 23 weeks of gestation. Analytes included common PCB congeners, the DDT metabolites p,p'-DDE, and o,p'-DDE as well as the pesticides: hexachlorobenzene (HCB); and the three isomers of hexachlorocyclohexane (alpha,beta and gamma-HCH). The limit of quantitation (LOQ) for PCBs was 0.01 ng/ml and for the other organochlorines contaminants is was 0.1 ng/ml. The contaminants alpha-HCH with a mean (+/- SD) concentration of 0.15 +/- 0.06 (ng/ml) and p,p'-DDE with a mean (+/- SD) concentration of 0.21 +/- 0.18 ng/ml were detected in the amniotic fluid. PCB specific congeners were detected with a much lower frequency and levels were in the range of the LOQ. Overall one in three amniotic fluid samples tested positive for at least one environmental contaminant. Therefore, we conclude that approximately one in three fetuses in the Los Angeles area are exposed to endocrine modulatory environmental contaminants in utero the consequences of which remain unknown at this time.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".