Effects of Prostaglandins and Indomethacin on Cerebral BloodFlow and Cerebral Oxygen Consumption of Conscious Newborn Piglets
Bibliographic record
Abstract
The effects of the prostaglandins (PG) PGE1, PGE2, PGF2 alpha and PGI2, and of indomethacin on cerebral blood flow (CBF) and cerebral metabolic rate for O2 (CMRO2) were studied in 60 1- to 3-day-old conscious piglets. Effects of PGs in indomethacin-treated animals were also measured. CBF was measured by radiolabelled microspheres prior to and 45 s after intracarotid bolus injections of 0.1-10 micrograms/kg PGE1 and 0.01-1 micrograms/kg PGE2, PGF2 alpha and PGI2. PGE1 decreased CBF by 30% at the dose of 0.1 micrograms/kg and increased it by 39.5% (n = 6) at the higher dose of 10 micrograms/kg. PGE2 (n = 6) increased CBF at all doses administered. PGF2 alpha (0.01 micrograms/kg, n = 8), which is a potent cerebral vasoconstrictor in adults, and PGI2 (0.1 micrograms/kg, n = 6) significantly increased CBF in newborn piglets (p less than 0.05). CMRO2 correlated with CBF in all groups of animals, except for those injected with PGI2. Indomethacin (3 mg/kg i.v.) decreased CBF by 39% (p less than 0.01, n = 6). This effect was partially reversed by PGI2, but not by PGE1 and PGF2 alpha. Sagittal venous blood and arterial-sagittal venous blood differences in concentrations of PGF2 alpha, but not of PGE and 6-keto-PGF1 alpha, correlated weakly but positively (r = 0.4, p less than 0.05) with CBF in indomethacin-treated piglets. These data indicate that PGs exert significant effects on cerebral circulation in the newborn. Primary PGs are principally cerebral vasodilators and are devoid of vasoconstrictive effects in the newborn, except for PGE1 which produces vasoconstriction at low dose (0.1 micrograms/kg). Thus, we speculate that a relative deficiency in cerebral vasoconstrictor effect of PGs may contribute to the reduced upper limit of the CBF autoregulatory range of the newborn.
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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 | 0.000 |
| 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 | 0.001 |
| 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".