Isometric pressure myography enables measurement of maximal vascular vasoconstriction and authentic EC <sub>50</sub>
Bibliographic record
Abstract
Both isometric wire and isobaric pressure myography have limitations. Wire myography distorts the vessel, may damage the endothelium, and limits intraluminal perfusion. On the other hand, occlusion of the vessel lumen may preclude measurement of maximal responses in the pressure myograph. We developed a system whereby the response of pressurized vessels could be measured under isometric conditions. We used the video dimension analyzer and servo controller of a classical pressure myograph (Living Systems Instrumentation) to maintain mesenteric and tail artery segments at a constant diameter by changing the intraluminal pressure. Concentration‐response curves for phenylephrine showed a classical sigmoidal form (pressure vs concentration), from which we were able to determine maximal response and EC 50 . The EC 50 for the mesenteric arteries was significantly lower by isometric pressure myography (4.5±0.7x10 −7 M, n=5) than by wire myography (Kent Scientific) (20.4±2.0x10 −6 M, n=7). On the isometric pressure myograph system, there was a rightward shift of the curve in the presence of prazosin. We propose that isometric pressure myography, which may be readily achieved with minimal modification of existing equipment, offers significant advantages over classical isobaric pressure myography. It allows for estimation of a true maximal constrictive response, and calculation of an authentic EC 50 . CIHR
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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 | 0.001 | 0.001 |
| 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) | 0.003 | 0.001 |
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".