Accumulation of dMHC positive fibers contributes to sarcopenia
Bibliographic record
Abstract
Sarcopenia is associated with accumulation of very small fibers amongst fibers of normal size. Previously, it was observed that some of these fibers in soleus muscle expressed a marker of regenerating muscle, developmental myosin heavy chain (dMHC). The purpose of this study was to determine the incidence of dMHC positive fibers across the range of muscle phenotypes from slow oxidative (soleus muscle; Sol), to fast oxidative (red region of gastrocnemius muscle; Gr) to fast glycolytic (white region of gastrocnemius muscle; Gw) muscle in senescent rats. Mean fiber size was 54% smaller in Sol, 43% smaller in Gr, and 67% smaller in Gw versus young adult rats. Whereas the fraction of dMHC positive fibers in Sol (12.6 +/− 2.8%) and Gas (8.5 +/− 1.5%) was similar, Gr (19.4 +/− 6.4%) had a higher dMHC expression than Gw (4.4 +/− 1.4%). In all muscle regions, the fiber cross‐sectional area of dMHC positive fibers was smaller than dMHC negative fibers. These results show that dMHC positive fibers are present across the range of metabolic and contractile phenotypes in aged muscles, and their small size shows that the accumulation of these fibers contributes to the decline in muscle mass with aging.
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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 | 0.001 | 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".