Plasma-accessible carbonic anhydrase at the tissue of a teleost fish may greatly enhance oxygen delivery:<i>in vitro</i>evidence in rainbow trout,<i>Oncorhynchus mykiss</i>
Bibliographic record
Abstract
During a generalized acidosis in rainbow trout, catecholamines are released into the blood, activating red blood cell (RBC) Na(+)/H(+) exchange (βNHE), thus protecting RBC intracellular pH (pH(i)) and subsequent O(2) binding at the gill. Because of the presence of a Root effect (a reduction in oxygen carrying capacity of the blood with a reduction in pH), the latter could otherwise be impaired. However, plasma-accessible carbonic anhydrase (CA) at the tissues (and absence at the gills) may result in selective short-circuiting of RBC βNHE pH regulation. This would acidify the RBCs and greatly enhance O(2) delivery by exploitation of the combined Bohr-Root effect, a mechanism not previously proposed. As proof-of-principle, an in vitro closed system was developed to continuously monitor extracellular pH (pH(e)) and O(2) tension (P(O(2))) of rainbow trout blood. In this closed system, adding CA to acidified, adrenergically stimulated RBCs short-circuited βNHE pH regulation, resulting in an increase in P(O(2)) by >30 mmHg, depending on the starting Hb-O(2) saturation and degree of initial acidification. Interestingly, in the absence of adrenergic stimulation, addition of CA still elevated P(O(2)), albeit to a lesser extent, a response that was absent during general NHE inhibition. If plasma-accessible CA-mediated short-circuiting is operational in vivo, the combined Bohr-Root effect system unique to teleost fishes could markedly enhance tissue O(2) delivery far in excess of that in vertebrates possessing a Bohr effect alone and may lead to insights about the early evolution of the Root effect.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 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".