Blood Flow during Handgrip Exercise in COPD
Bibliographic record
Abstract
PURPOSE: Chronic obstructive pulmonary disease (COPD) is associated with vascular dysfunction, possibly related to increased oxidative stress. Exercise hyperemia may similarly be impaired, which could have implications for exercise limitations in COPD. We tested if brachial blood flow (BBF) was reduced during handgrip exercise in COPD and if this response would be improved after vitamin C infusion. METHODS: Doppler ultrasound was used to measure brachial blood flow and vascular conductance (BBF and BVC, respectively) during mild, rhythmic handgrip exercise (EX) under conditions of sham-saline and vitamin C. Measures of flow-mediated dilation (FMD) and nitroglycerine-mediated dilation were used to assess endothelial-dependent and independent dilation, respectively. Biomarkers of antioxidants (vitamin C, superoxide dismutase [SOD], catalase), oxidative stress (malondialdehyde [MDA], advanced oxidation protein products [AOPP]), and nitric oxide metabolism (NOx) were measured in blood plasma. RESULTS: Ten COPD patients with moderate COPD and 10 healthy age-matched controls participated. COPD patients had similar increases in BBF and BVC during EX, compared with controls. Vitamin C was not found to have an effect on blood flow parameters during exercise (P > 0.05). Markers of endothelial-dependent dilation (FMD) and nitroglycerin-mediated dilation were similar between groups at baseline; FMD improved similarly in both groups after vitamin C. CONCLUSIONS: Moderate COPD patients have a preserved BBF response during handgrip exercise and do not exhibit endothelial dysfunction. Despite an increase in endothelial-dependent dilation after vitamin C, BBF remained unchanged, suggesting a limited impact of endothelial-derived NO in determining the blood flow response to handgrip exercise in older individuals. COPD patients of moderate severity, screened for cardiovascular disease, do not exhibit endothelial dysfunction and have similar exercise blood flow responses to healthy controls.
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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 | 0.001 |
| 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 | 0.000 |
| 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".