Contractile function in vitro of slow-twitch skeletal muscle from weanling mice subjected to wasting malnutrition
Bibliographic record
Abstract
Our hypothesis was that malnutrition sufficient to produce weight loss in weanling mice would decrease the ability of slow-twitch skeletal muscle to develop and maintain force. We isolated muscles from 3 groups (n = 5) of weanling C57BL/6J mice of both sexes (i) mice at 19 days of age serving as zero-time or baseline controls (CONT) (ii) mice fed for the next 14 days with a low-protein diet that produces features of incipient kwashiorkor (LPD) and (iii) mice fed for the next 14 days with a complete diet (NORM). Muscles were also obtained from 5 adult mice 79 months of age (MAT). We stimulated the soleus at 50 Hz for 500 ms at 0.6 tetanic contractions per min (tet·min1), 6 tet·min1, and 30 tet·min1in Krebs-Henseleit bicarbonate buffer at 27°C gassed with 95% O2and 5% CO2. The initial developed force (mN·mm2) at 0.6 tet·min1did not differ across groups (CONT 211.7 ± 16.0, LPD 274.2 ± 41.6, NORM 246.8 ± 38.0, MAT 210.8 ± 10.6). The fatigue rate (mN·mm2·min1) at 6 tet·min1was significantly slower in muscles from CONT (0.6 ± 0.3) and LPD (0.6 ± 0.4) than in NORM (2.4 ± 0.6) and MAT (2.3 ± 0.2). At 30 tet·min1, the fatigue rate (mN·mm2·min1) did not differ across groups (CONT 2.4 ± 0.5, LPD 2.7 ± 0.5, NORM 2.5 ± 0.4, MAT 2.0 ± 0.2). After stimulation at 6 tet· min1and 30 tet·min1, only muscles from CONT and LPD recovered to 100%. Because muscles from LPD mice developed equal force, fatigued less, and recovered from fatigue to a greater extent than muscles from NORM mice, we rejected the hypothesis. The function of the tissue remaining in the muscles from LPD mice approximated that of muscles from mice at 19 days of age rather than muscles from either mice of the same age fed a complete diet or adult mice.Key words: developed force, fatigue, recovery from fatigue.
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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 | 0.001 |
| 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".