A Posteromedial Approach to a Complex Multifragmentary Avulsion Fracture of the Posterior Cruciate Ligament: A Case ReportEx-vivo Evaluation of 99mTc Labeled Glucosamine Sulfate(99mTcGS) in Articular Cartilage. Relevance for Osteoarthritis Imaging
Bibliographic record
Abstract
Background: Glucosamine sulfate (GS) is widely used in the treatment of osteoarthritis, but no data concerning the local uptake of GS in articular cartilage exist.For this reason we performed radiolabeling of GS (Rottapharm, Monza, Italy) using the 99m TcO 4 -/ tin method and investigated its uptake in articular cartilage.Methods: Radiolabeling of GS is difficult, because of the small MW of GS (450 Da) and of 99m TcO 4 -for separation after radiolabeling.For uptake studies, articular surgery tissue from patients (n=6, 68-79a) undergoing knee arthroplasty (pieces of ~3 mg wet weight), or frozen tissue sections (10 µ) for autoradiography (10 µCi) were used.The uptake of 99m TcGS was monitored from 0.5 to 72 h of incubation to achieve saturation, by quantitation of radioactivity with a Gammacounter or autoradiography.To mimic in-vivo treatment, tissue pieces were preincubated with cold GS (80 µg/ml) for 16 weeks prior to incubation with 99m TcGS.The incubation was performed with tissues with different degree of degeneration.Results: The best radiolabeling results were obtained using 25 mg of GS, 120-150 MBq of 99m Tc, separation on G10 column, specific activity of 162.2-202.8mCi/mM, n=6.The uptake was time-dependent and amounted to a maximum of 77.4.-71.7% at 48 h versus 72 h, at saturation.Saturation was achieved already after 24 h of incubation.When the tissue was preincubated with cold GS the subsequent uptake of 99m TcGS was strongly reduced by 52.3-71.8%,proving the chondrotropic effects of GS during preincubation.The reduction of 99m TcGS uptake was observed also in areas of different grades of degeneration from the same patient by 27.8-35.8%,proving the specificity of uptake.Autoradiographic studies paralleled the uptake in tissue pieces.We performed a statistical evaluation of differences between all investigated OA patients with different degree of cartilage degeneration.For these patients we evaluated the autoradiographic uptake at all experimental points of incubation times (1 h, 3 h, 6 h, 24 h, 48 h).99m TcGS uptake in tissues of different extent of degeneration varied significantly during the whole time of incubation, the more degenerated regions showing a significantly higher 99m TcGS uptake.The non-specific uptake in the presence of 50-fold excess of cold GS was increasing with time up to a maximum of about 10%, at saturation. Conclusions: 99mTcGS could be a suitable tracer to quantify degeneration in articular cartilage, because of its high uptake and specificity.It could be a potential candidate for imaging osteoarthritis in cartilage and possibly for monitoring therapeutic effects.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.005 | 0.004 |
| Meta-epidemiology (broad) | 0.003 | 0.004 |
| Bibliometrics | 0.006 | 0.004 |
| Science and technology studies | 0.005 | 0.005 |
| Scholarly communication | 0.003 | 0.005 |
| Open science | 0.003 | 0.004 |
| Research integrity | 0.018 | 0.010 |
| Insufficient payload (model declined to judge) | 0.008 | 0.003 |
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".