Physiological concentrations of nicotine do not affect prostacyclin, thromboxane or PGE production from perfused human umbilical veins
Bibliographic record
Abstract
Abstract Smoking during pregnancy is associated with a number of maternal and fetal complications. The mechanisms underlying the effects of nicotine on fetal growth and development are not known, but may involve decreases in umbilical–placental blood flow. Prostaglandins are vasoactive mediators that regulate umbilical–placental blood flow and there is evidence that nicotine may alter prostaglandin production. Thus, alterations in vasoactive prostaglandins from the human umbilical vein may explain nicotine‐induced decreases in vessel blood flow and may underlie some of the negative effects of nicotine on the fetus. This study was designed to determine the relationship between nicotine and human umbilical vein prostaglandin production. Prostacyclin, thromboxane and prostaglandin E were measured from human umbilical veins collected from women at the time of cesarean section. Vessels were perfused with either vehicle (Dulbecco's modified Eagle's media), 5 mM, 10 mM or 20 mM nicotine for 60 minutes. Samples were collected from the perfusate after 5, 15, 30 and 60 minutes of perfusion, and prostaglandins were measured by radioimmunoassay. Data were analyzed by ANOVA. Perfusion with 10 mM or 20 mm significantly reduced prostacyclin production by the human umbilical veins, but nicotine did not affect prostaglandin E. The effects of nicotine on thromboxane were less clear. However, nicotine concentrations required to illicit an effect on prostacyclin production were much larger than circulating levels associated with smoking, so it is only pharmacological concentrations that have a significant effect. Thus, nicotine‐induced alterations in umbilical vein prostaglandin production does not appear to be a mechanism by which nicotine adversely affects fetal growth and development.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.017 | 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 teacher head, 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".