Effect of intermittent umbilical cord occlusion on fetal respiratory activity and brain adenosine in late-gestation sheep
Why this work is in the frame
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Bibliographic record
Abstract
It was hypothesized that intermittent umbilical cord occlusion (UCO) would inhibit ovine fetal breathing movements (FBM) in association with increased cerebral adenosine levels. To test this hypothesis, on two successive days during late gestation (133-134 days; term = 146 days), microdialysis samples were collected from the brains of 10 chronically instrumented fetal sheep during 2-h periods of complete UCO induced every 30 min (Day 1: 2-min UCOs; Day 2: 4-min UCOs). Control fetuses (n = 10) underwent no UCO. Tracheal pressure was measured throughout. This regimen resulted in a decrease in fetal arterial PO2 (PaO2) during each UCO to 7.3 +/- 0.8 mmHg (P<0.01; Day 1) and 8.4 +/- 1.1 mmHg (P<0.01; Day 2). Throughout each UCO period, fetal arterial pH (pHa) decreased to 7.28 +/- 0.02 (P<0.01; Day 1) and 7.11 +/- 0.07 (P<0.01; Day 2). The hourly incidence of FBM decreased significantly only on Day 2, from 38.6 +/- 4.1% to 4.1 +/- 1.6% (P<0.01). The frequency of deep isolated inspiratory efforts increased from 4.7 +/- 2.0 h(-1) to 17.6 +/- 6.1 h(-1) (P<0.05; Day 1) and from 2.2 +/- 0.9 h(-1) to 33.6 +/- 4 h(-1) (P<0.01; Day 2). The amplitude of both FBM and deep isolated inspiratory efforts increased during the UCO periods on both days. The concentration of cerebral extracellular fluid (ECF) adenosine during UCO increased by 219 +/- 215% (P<0.05; Day 1) and 172 +/- 107% (P<0.05; Day 2) over the baseline periods. In conclusion, the severity of the inhibitory effect of repeated UCO on FBM depends, in part, on the length of the occlusions. The inhibition of FBM during intermittent UCO may be mediated by the increase in ECF adenosine in the fetal brain. Furthermore, FBM and deep isolated inspiratory efforts appear to be regulated by different mechanisms.
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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 | 0.001 | 0.002 |
| 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 it