Brachial artery flow‐mediated constriction and dilation in response to a cardiovascular stress: potential influence of age (LB683)
Bibliographic record
Abstract
Low‐flow mediated constriction (L‐FMC) is a measure of vascular function complementary to flow‐mediated dilation (FMD). L‐FMC is commonly observed in the radial artery, however its presence in the brachial artery is equivocal. Furthermore, the effects of age and an acute cardiovascular stress on L‐FMC are unknown. We measured brachial L‐FMC and FMD (% change) during and following 5‐min of distal forearm occlusion in healthy young (n=7; 29±6 years [mean ± SD]) and old (n=5; 64±5 years) women before and after acute isometric handgrip exercise (IHG; 4, 2‐min unilateral contractions, each separated by 4‐min of rest, at 30% maximal voluntary contraction). Baseline L‐FMC and FMD were similar between groups (Both P >0.05). Acute IHG increased FMD in young (6.7±2.2% to 10.4±3.9%, P <0.05), but not old (7.3±5.4% to 9.7±9.6%, P >0.05) women, while L‐FMC was unchanged ( P >0.05) in both groups (young: ‐3.5±6.3% to ‐3.7±4.5%; old: ‐5.5±9.5% to ‐4.0±9.0%). In young women, brachial L‐FMC and FMD were correlated before ( r = 0.90; P <0.05) and after IHG ( r = 0.97; P <0.05). In older women, L‐FMC and FMD were unrelated before ( r = ‐0.20; P =0.74) but trended towards a correlation after IHG ( r = 0.82 ; P =0.09). In conclusion, L‐FMC is observed in the brachial artery of healthy young and old women. Acute IHG appears to restore the relationship between constriction and dilation in old women. Grant Funding Source : Supported by the University of Windsor
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".