Greater frequency and concentration of satellite cells at the ends of developing skeletal muscle fibers
Bibliographic record
Abstract
Satellite cells (SCs) are mononuclear myogenic stem cells located immediately beneath the basal laminae of skeletal muscle fibers. Once activated, SCs fuse to the fibers as new myonuclei. Since myonuclei are more concentrated in tapered fiber ends, this study tests the hypothesis that there is a greater frequency (number of SC nuclei over all nuclei within the basal laminae) and a higher concentration of SCs at the ends of skeletal muscle fibers. Chicken pectoralis was used as the experimental model because of its overlapping fibers and the presence of neonatal myosin in the fiber ends. Samples were excised from birds ranging in age from nine to 115 days. Antibodies against Pax7 were used to identify SC nuclei. Applying immunocytochemical techniques and computer image analyses, the frequency of SCs was quantified for different types of fiber profiles (neonatal, transforming and adult) and with regards to fiber size. While the frequency of SCs decreased significantly (P<0.01) with age from about 20% to less than 5%, along the fiber lengths the ends retained the highest frequency ranging between 20‐13%. Also, the area of plasmalemma per SC was calculated for each type of fiber profile. There was significantly (P<0.05) less plasmalemma per SC at the ends of the fibers. This study demonstrates that throughout development there is a higher frequency and concentration of SCs at the tapered ends of skeletal muscle fibers. Funds for this study were provided by the Natural Sciences and Engineering Research Council 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 | 0.001 | 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) | 0.002 | 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".