O<sub>2</sub>affinity of cross-linked hemoglobins modifies O<sub>2</sub>metabolism in proximal tubules
Bibliographic record
Abstract
Previous experiments using cross-linked tetrameric hemoglobins (XLHb) to perfuse isolated rat kidneys showed that high-O2-affinity XLHb improved proximal tubule function more effectively than low-O2-affinity XLHb. To determine how function was improved, proximal tubule fragments were incubated with albumin, Hb34[half-saturation point (P50) 34 Torr], or Hb13(P5013 Torr) with Po2values ranging from 22 to 147 Torr. ATP content reflected O2delivery to mitochondria. Both XLHb increased ATP, Hb34with Po2≥ 47 Torr and Hb13with Po2≤ 47 Torr. XLHb increased Na-K-ATPase activity (86Rb uptake) in similar Po2-dependent patterns. O2consumption (Q̇o2) was measured in a closed, well-stirred chamber. Ouabain- and oligomycin-inhibited Q̇o2, reflecting Na-K-ATPase activity and oxidative phosphorylation, respectively, mirrored the Po2-dependent patterns of ATP and86Rb uptake. As Po2fell below the midpoint of XLHb desaturation, Q̇o2, uncoupled from oxidative phosphorylation, transiently increased. The increase was most pronounced with Hb34. Nitro-l-arginine methyl ester had no effect on Q̇o2. Inhibitors of NAD(P)H oxidases and diamine oxidase partially prevented the Q̇o2surge with Hb34. In conclusion, facilitated diffusion accounts for Po2-dependent XLHb effects on ATP content and Na-K-ATPase and for Hb13's effectiveness in hypoxic perfused kidneys. NO scavenging was not a factor. O2-binding characteristics influence XLHb effects on mitochondria and O2-sensitive enzymes such as oxidases.
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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 | 0.000 |
| 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 | 0.000 |
| 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".