The role of Vitamin D metabolic enzymes in bone development and repair /
Bibliographic record
Abstract
The CYP27B1 enzyme that synthesizes 1alpha,25-(OH) 2D, is expressed in chondrocytes, suggesting that local production of 1alpha,25-(OH)2D could play an autocrine or paracrine role in the differentiation of these cells. To test this hypothesis, we have engineered mutant mice that do not express the Cyp27b1 gene in chondrocytes. This led to increased width of the hypertrophic zone of the growth plate at E15.5, increased bone mass in neonatal long bones, and increased expression of the chondrocytic differentiation markers Indian Hedgehog and PTH/PTHrP receptor. VEGF mRNA levels were decreased, accompanied by decreased PECAM-1 immunostaining, suggesting a delay in vascularization. We have also engineered mice overexpressing a Cyp27b1 transgene in chondrocytes. The transgenic mice showed a partial mirror image phenotype compared to the tissue-specific inactivation model. These results support an autocrine/paracrine role of 1alpha,25-(OH) 2D in endochondral ossification and chondrocyte development in vivo.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".