Adaptation of cardiovascular responses to repetitive umbilical cord occlusion in the late gestation ovine fetus
Bibliographic record
Abstract
1. The impact of repeated umbilical cord occlusion on the normal maturation of fetal heart rate (FHR) and mean arterial pressure (MAP) and the cardiovascular responses to successive umbilical cord occlusion was investigated over a 21 day period in the latter part of gestation. 2. Fifteen chronically instrumented sheep (control group n = 6; occlusion group n = 9) were studied for 21 days (113-133 days of gestation, term = 145 days) with umbilical cord occlusions (90 s duration) performed every 30 min for 1-4 h each day. On days 1, 9 and 18, FHR, FHR variation and MAP were monitored continuously and fetal arterial blood gases, pH and metabolites were measured at predetermined intervals. The baroreflex response to 75-100 microg phenylephrine (I.V.) was tested on days 1 and 18. 3. Basal FHR decreased (DeltaFHR: control, 34.6 +/- 3.6 beats x min(-1); occlusion, 36.9 +/- 2.7 beats x min(-1)) and MAP increased (DeltaMAP: control, 3.1 +/- 1.7 mmHg; occlusion, 5.2 +/- 2.1 mmHg) to a similar extent in control and occlusion groups between days 1 and 21 of the study. There was a small decline in FHR variation over the 21 day study in occlusion, but not control, group fetuses. 4. The magnitude of the fall in FHR decreased and the rise in MAP increased, despite similar changes in blood gases in response to umbilical cord occlusion, over the course of the 21 day study. Despite a significant decline in the ratio of DeltaFHR to DeltaMAP on days 9 and 18 compared to day 1, there was no difference between control and occlusion groups in baroreflex sensitivity. However DeltaFHR/DeltaPO2, an index of chemoreceptor sensitivity, had decreased by day 9 and 18 compared to day 1. 5. The cardiovascular responses to umbilical cord occlusion are altered with repetitive occlusions during the latter part of gestation, with a decrease in DeltaFHR/DeltaMAP, which does not involve changes in baroreflex sensitivity, but may involve changes in chemoreceptor sensitivity. However, repeated umbilical cord occlusion appears to have no impact on baseline cardiovascular control since there was no change in the normal maturational decrease in FHR and rise in MAP.
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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 | 0.002 | 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) | 0.000 | 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".