Oxidative capacity interacts with oxygen delivery to determine maximal O<sub>2</sub> uptake in rat skeletal muscles <i>in situ</i>
Bibliographic record
Abstract
Based on proportional changes in V(O(2))(,max) with alterations in O(2) delivery, it is widely held that O(2) availability limits V(O(2))(,max). In contrast, reductions in V(O(2))(,max) are also seen when mitochondrial oxidative capacity is reduced. Taken collectively, these prior results are consistent with the notion that there is not a single-step limitation to V(O(2))(,max). We used a pump-perfused rat hindlimb model to test the hypothesis that combining moderate reductions in O(2) delivery and mitochondrial oxidative capacity would yield a greater reduction in V(O(2))(,max) than seen when performing each intervention independently, demonstrating an interaction between O(2) supply and mitochondrial oxidative capacity in determining V(O(2))(,max). Four groups of animals were studied: two in high O(2) delivery conditions (hindlimb O(2) delivery: 88 +/- 1 micromol O(2) min(-1); mean +/- S.E.M.) and two in moderately reduced O(2) delivery conditions (66 +/- 2 micromol O(2) min(-1)). One group at each level of O(2) delivery was treated with 0.1 microM myxothiazol to reduce mitochondrial oxidative capacity via competitive inhibition of NADH cytochrome c reductase. V(O(2))(,max) in control animals (no myxothiazol) was 29 % lower in the moderately reduced O(2) delivery group (592 +/- 24 mmol O(2) min(-1) (100 g)(-1)); P < 0.05) than in the high O(2) delivery group (833 +/- 63 micromol O(2) min(-1) (100 g)(-1)). Similarly, V(O(2))(,max) was reduced by 29 % (594 +/- 22 micromol O(2) min(-1) (100 g)(-1)); P < 0.05) in myxothiazol-treated animals in high O(2) delivery conditions compared to control animals in high O(2) delivery conditions. When myxothiazol treatment was combined with moderately reduced O(2) delivery, V(O(2))(,max) was reduced by an additional 18 % (484 +/- 21 micromol O(2) min(-1) (100 g)(-1)); P < 0.05) compared to either intervention performed independently. These results show that O(2) supply and mitochondrial oxidative capacity interact to determine V(O(2))(,max).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".