A NEW ENDOTHELIAL FUNCTION TEST REDUCES TRIAL TO TRIAL STIMULUS AND RESPONSE VARIABILITY
Bibliographic record
Abstract
Non-invasive tests to quantify endothelium dependent flow-mediated dilation (EDFMD) have important clinical and basic research applications. With the current EDFMD test which employs reactive hyperemia (RH) as a shear stress stimulus, there is considerable stimulus and response variability. PURPOSE To develop an EDFMD test that achieves reduced trial-to-trial shear stress-stimulus and EDFMD-response variability vs. the current test. METHODS Brachial artery diameter (BAD) and mean blood velocity (MBV) were measured beat-by-beat (Doppler ultrasound) in 6 healthy young males. The new test individualizes target MBV increases based on subject BAD in order to to achieve common shear rates (SR; estimate of shear stress = MBV/BAD) across subjects. Therefore we report MBV values. RH test: a transient SR stimulus was evoked via release of 5 min of forearm occlusion. NEW test: a controlled SR of 8−1 was maintained with brachial artery compression during 30 min of forearm heating. Controlled compression release created a step increase is SR to 50−1 maintained for 5 min. Re-establishment of SR at 8−1 allowed BAD to return to baseline. For both tests, two trials were performed. RESULTS All data are mean ±SD. The coefficient of variation (CV) between trials for total MBV in the 1 st min was significantly less for the NEW test vs. the RH test (4.3 ± 4.2% vs. 9.3 ± 3.8%, P = 0.02). Difference between target and actual MBV over 5 min for the NEW test was minimal and not different between trials (Trial1 0.07 ± 0.79 cm/s vs. Trial2 0.20 ± 0.3 cm/s, P = 0.86). The CV between trials for peak % Δ in diameter was significantly less for the NEW vs. RH test (3.2 ± 4.1% vs. 18.3 ± 15.1%, P = 0.03), although as expected, the magnitude of diameter changes was greater with the RH vs. NEW test (6.8 ± 3.0% vs. 3.3 ± 0.9%, P < 0.01). CONCLUSION The new test achieves a controlled, sustained stimulus for EDFMD and significantly reduced trial-to-trial stimulus and EDFMD response variability. Supported by NSERC; CFI New Opportunities Fund
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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 | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".