Renal Calcification in Mice Homozygous for the Disrupted Type IIa Na/Pi Cotransporter Gene <i>Npt2</i>
Bibliographic record
Abstract
Mice homozygous for the disrupted renal type IIa sodium/phosphate (Na/Pi) cotransporter gene (Npt2-/-) exhibit renal Pi wasting, hypophosphatemia, and an adaptive increase in the serum concentration of 1,25-dihydroxyvitamin D with associated hypercalcemia and hypercalciuria. Because hypercalciuria is a risk factor for nephrocalcinosis, we determined whether Npt2-/- mice form renal stones. Analysis of renal sections by von Kossa staining and intact kidneys by microcomputed tomography revealed renal calcification in adult Npt2-/- mice but not in Npt2+/+ littermates. Energy-dispersive spectroscopy and selected-area electron diffraction indicated that the calcifications are comprised of calcium and Pi with an apatitic mineral phase. To determine the age of onset of nephrocalcinosis, we examined renal sections of newborn and weanling mice. At both ages, mutant but not wild-type mice display renal calcification, which is associated with renal Pi wasting and hypercalciuria. Immunohistochemistry revealed that osteopontin co-localizes with the calcifications. Furthermore, renal osteopontin messenger RNA abundance is significantly elevated in Npt2-/- mice compared with Npt2+/+ mice. The onset of renal stones correlated developmentally with the absence of Npt2 expression and the expression of the genes responsible for the renal production (1alpha-hydroxylase) and catabolism (24-hydroxylase) of 1,25-dihydroxyvitamin D. In summary, we show that Npt2 gene ablation is associated with renal calcification and suggest that mutations in the NPT2 gene may contribute to nephrocalcinosis in a subset of patients with familial hypercalciuria.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".