Prothrombin gene expression in articular cartilage with a putative role in cartilage degeneration secondary to joint immobility.
Bibliographic record
Abstract
OBJECTIVE: To test the hypothesis that thrombin is expressed by chondrocytes from human and animal articular cartilage and to monitor its levels of expression during cartilage degeneration induced by joint immobility in a rat model. METHODS: Rat knees were immobilized for periods of 2 or 4 weeks, after which the articular cartilage was harvested, total RNA extracted, and the differential display (ddPCR) protocol applied to identify differentially expressed genes. One differentially expressed fragment showed 100% homology with the prothrombin gene. Results were verified by RT-PCR, Northern and Western blot analysis, and immunohistochemistry in human, rat, and rabbit articular cartilage. RESULTS: In our rat model of cartilage degeneration induced by joint immobilization, increases in the levels of prothrombin mRNA, thrombin protein, and fibrin deposition were observed. Expression of the prothrombin gene by chondrocytes was confirmed by ddPCR (rat), RT-PCR (rat and human), and by Northern blot analysis (rabbit). In addition, thrombin-like immunoreactivity was increased in chondrocytes after a 4 week immobilization period compared with rat knees receiving sham surgery. Thrombin activity was reflected by the presence of fibrin immunoreactivity in operated rat knee joints. CONCLUSION: Articular chondrocytes express the prothrombin gene and its local expression in joints is translated into thrombin protein. Prothrombin expression is increased in response to joint immobility. Our results support generation of thrombin locally in joints and an upregulation of thrombin expression in cartilage degeneration secondary to immobility. These results may provide information on the source of increased thrombin activity in various animal models and in clinical forms of arthritis.
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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".