Flow induces dilatation in the femoral artery of uraemic rats but constriction in control rats
Bibliographic record
Abstract
BACKGROUND: Pressure and flow are recognized as important modulators of vascular tone. In mildly uraemic rats, myogenic tone is increased in the femoral artery in the absence of hypertension compared with healthy control rats, but the effect of flow in the same experimental model remains unknown. SUBJECTS AND METHODS: Twelve male Wistar rats were rendered uraemic (U) by 5/6th nephrectomy or were concurrently sham operated as controls (C). After 8 weeks, isolated femoral arteries were mounted on a flow myograph, pressurized at 80 mmHg, and constricted by 40-50% of the lumen internal diameter (i.d.) by L-phenylephrine (1-10 micromol/l). Flow was initiated (0-207 microl/min) in six steps every 5 min and changes in i.d. recorded. N-nitro-L-arginine methyl ester hydrochloride (L-NAME) (0.1 mmol/l) and 1H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) (1 micromol/l) were applied extraluminally and the flow protocol repeated. RESULTS: The baseline pre-constricted at 80 mmHg i.d. was significantly smaller in the U (U 255+/-21 microm vs C 365+/-36 microm, P<0.03). At all steps, flow elicited a dilatation in the U and a constriction in the C (U+ 24+/-8% vs C-17+/-5%, P<0.01). When L-NAME and ODQ were applied, a significant basal reduction in i.d. was observed in the C only (C 365+/-36 microm vs C+ L-NAME & ODQ 182+/-18 microm, P<0.01; U 255+/- 21 microm vs U+L-NAME & ODQ 240+/-11 microm, P=n.s.). Furthermore, in the U there was no significant blunting to dilatation during flow (+9+/-4%). CONCLUSIONS: Flow elicited a constriction in controls, but a marked dilatation in uraemic roots which was not entirely nitric oxide dependent. These results suggest that other mediators such as prostacyclin or endothelium-dependent hyperpolarizing factor, or changes in the vascular smooth muscle may contribute to flow-induced dilatation in mild experimental uraemia.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.003 | 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".