Impact of shifting epithelial Na <sup>+</sup> transport on renal medullary oxygen tension: Modeling and analysis
Bibliographic record
Abstract
The mammalian kidney is particularly vulnerable to hypoperfusion, because O 2 supply to the renal medulla barely exceeds its O 2 requirements. Renal O 2 consumption is mainly driven by the metabolic work of tubular Na + reabsorption. In this study, we examined the impact of shifting the Na + transport site on medullary oxygen tension (P O2 ) of the rat kidney. To accomplish that goal, we extended our published model of renal epithelial transport to include renal vasculature and to simulate the crosstalk among nephron segments and vasculature. The model represents the complex structural organization of the medulla, which is believed to have a significant impact on medullary O 2 distribution. The transport of red blood cells, hemoglobin, and O 2 was explicitly represented. We considered basal cellular O 2 consumption and O 2 consumption for Na + /K + ‐ATPase‐mediated transport. Our model predicts that the structural organization of the outer medulla results in significant Po 2 gradients in the axial and radial directions. The segregation of descending vasa recta, the main supply of O 2 , at the center and immediate periphery of the vascular bundles gives rise to large radial differences in Po 2 , limits O 2 reabsorption from long descending vasa recta, and helps preserve O 2 delivery to the inner medulla. When Na + delivery to the S3 and thick ascending limb segments is elevated (e.g., by pharmacological manipulation), local interstitial P O2 may decrease significantly, a result that indicates elevated risk of hypoxia. Support or Funding Information This research was supported by the Canada 150 Research Chair program and by the National Institutes of Health: National Institute of Diabetes and Digestive and Kidney Diseases, grant R01DK106102. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 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".