The role of C‐3 α epimer of 25‐hydroxyvitamin D on maintenance of bone mineral density
Bibliographic record
Abstract
The function of C‐3 α epimer (C‐3 Epi) of 25‐hydroxyvitamin D (25(OH)D) in vivo is unknown. In in vitro studies, C‐3 Epi is less potent in stimulating calcium transport but equivalent in suppressing parathyroid hormone. The objective was to compare C‐3 Epi to 25(OH)D and cholecalciferol in maintaining bone mineral density (BMD). Adult Sprague Dawley rats (12 weeks, n=36 female n=36 male) were randomized to: control AIN93‐M diet (2 IU vitamin D3/g food) or experimental diets for 8 weeks: C‐3 Epi at 0.5 and 1 IU/g food and a 25(OH)D group (0.5 IU/g food) reference group. Body weights and food consumption were measured weekly. Blood samples were collected at week 0, 4 and 8 as well as whole body dual‐energy X‐ray absorptiometry (DXA; QDR 4500A, Hologic). Differences were tested using a mixed model ANOVA. There were no differences among groups for weight or dietary intake. In females, the 1 IU C‐3 Epi group had higher whole body BMD compared to the cholecalciferol and 25(OH)D groups (Table 1); similar differences were observed in males (data not shown). These preliminary data suggest that C‐3 Epi is not detrimental to growth or bone. Future analyses including regional DXA and micro computed tomography plus biomarkers of bone metabolism are required to clarify the physiological responses. Research supported by NSERC and Dairy Farmers of Canada.
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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".