Attenuation of hypoxic pulmonary vasoconstriction by acetazolamide and methazolamide : a randomized crossover study.
Bibliographic record
Abstract
Context: Acetazolmaide (AZ) is used in the prophylactic treatment of altitude illnesses. AZ is also known to attenuate HPV and increase alveolar ventilation. Methazolamide (MZ) is an analog to AZ and its effects on ventilation and HPV are unknown. Objective. To determine if MZ can improve oxygenation and attenuate HPV to a similar extent as AZ in healthy humans exposed to poikilocapnic hypoxia. Design, Setting, Participants and Interventions: A randomized, placebo controlled, double-blinded trial was performed in healthy participants at the Cardiopulmonary Lab for Experimental and Applied Physiology. Prior to each of the three experimentation days, participants were administered one of three treatments (AZ, MZ, & placebo) at random for two days. Each treatment was separated by a 10-day washout period to avoid contamination from previous trials. During each trial, participants were exposed to poikilocapnic hypoxia (FIO2 ≈ 0.12) for 60 minutes. Primary Outcome Measures: Partial pressure of alveolar O₂ (PAO₂) represented oxygenation while pulmonary artery systolic pressure (PASP) and total pulmonary resistance (TPR) were chosen to represent the HPV response. Results: All participants (n = 11) completed all three trials. Change in Q̇ from baseline to hypoxia was not different between treatments. Change in PASP was significantly lower with the AZ (8.0 ± 0.7 mmHg) and MZ (9.0 ± 0.9 mmHg) treatments compared to placebo (PASP: 14.1 ± 1.3 mmHgP < 0.05). Change in PAO₂ was also decreased with both drug treatments (AZ: 54.8 ± 1.3 mmHg; MZ: 53.9 ± 1.3 mmHg) compared to placebo (48.5 ± 1.6 mmHg; P < 0.05). Conclusion: MZ attenuated HPV to the same degree as AZ. MZ also resulted in a similar improvement in PAO₂ as AZ during hypoxia compared to placebo. Trial Registration: This study was registered with the U.S. National Institutes of Health: NCT02760121 Funding: This project was funded by the Canadian Foundation for Innovation and by the Natural Science and Engineering Council of Canada.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.004 | 0.003 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.008 | 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".