DEVELOPMENT AND RAMAN SPECTROSCOPIC CHARACTERIZATION OF AN IN VITRO MODEL OF CALCIFIED CARTILAGE
Bibliographic record
Abstract
Osteoarthritis is a disease that affects millions of Canadians and for which there is no cure or disease-modifying drug to halt or reverse progression. While one of the primary characteristics of osteoarthritis is the degeneration of articular cartilage, histological evidence has pointed to thickening of the zone of calcified cartilage as a hallmark of its progression, the result of mechanisms which are not yet fully elucidated. It is the purpose of this work to develop an in vitro model of articular cartilage with a calcified zone, to be used in characterizing the effects of various stimuli on the mineralization process in cartilage. In this work, we aim to identify culture conditions that lead to the formation of a stable calcified layer. Deep zone cartilage was extracted from bovine metacarpophalangeal joints within 24h of death. Tissue was digested enzymatically to yield a suspension of deep zone chondrocytes, which was seeded at high density onto tissue culture membranes. Cultures were kept for up to eight weeks in media containing 10mM β-glycerophosphate (βGP), with select samples’ supplementation reduced to 0 or 3mM βGP after four weeks. In vitro-grown tissues were harvested for analysis at four-week intervals. Tissues harvested for quantification of mineral were digested in hydrochloric acid and assayed for calcium and phosphate content. Additional harvested tissues were fixed in formalin for 72 hours and histologically stained for mineral and matrix (von Kossa with hematoxylin counterstain) or mounted on plastic for Raman microspectroscopic analysis. Raman maps were collected using a 532 nm laser from a 200x200µm region in the deepest aspect of tissues, and peak masks for bands corresponding to relevant organic (Amide I at 1650cm-1) and inorganic (ν1(PO43-) at 960cm-1, ν1(CO32-) at 1060cm-1) vibrational modes were used to discriminate the zonal distribution of mineral. Calcium content of tissues revealed that mineral deposits steadily up to 8 weeks when maintained at 10mM βGP. Deposition of mineral slows significantly when supplementation is reduced to 3mM and when it is removed entirely. Von Kossa staining indicated that mineral deposits form a relatively uniform calcified layer in close proximity with the substrate and restricted to the deeper aspect of the tissues. While Raman spectroscopic analysis of tissues is ongoing, preliminary peak quantification shows that the mineral-to-matrix ratio (ν1(PO43-)/Amide I) is comparable to that in native tissue. Raman mappings indicate that removal or reduction of βGP supplementation results in reorganization of mineral visible at four weeks into a clearly-delimited uniform layer at eight weeks. The results summarized here demonstrate that a stable mineral zone may be achievable by tuning the supplementation of βGP at 4 weeks, after a contiguous layer has formed. Raman spectral mappings proved a useful tool in determining the structure and physicochemical properties of the zonal distribution in the model. Further studies with the model will include quantifying responses in the mineral layer to compressive forces, as well as inflammatory cytokine signaling.
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".