Are Abnormalities in Sarcoplasmic Reticulum Calcium Cycling Properties Involved in Trapezius Myalgia?
Bibliographic record
Abstract
OBJECTIVE: The aim of this study was to demonstrate the feasibility of using samples obtained through muscle biopsy to assess a wide range of cellular properties, some of which may be abnormal in myalgia. Given the recent emphasis on the role of excitation-contraction coupling in health and disease, special emphasis is given to the characterization of the properties involved in this process. DESIGN: Tissue samples were obtained from the upper portion of the descending trapezius muscle in three female patients (PAT) with clinically diagnosed myalgia and assessed for a spectrum of properties related to substrate use, energy production, and excitation-contraction coupling and were compared with samples from three healthy controls. RESULTS: At the level of organization of the metabolic pathways, all PAT generally displayed normal activities of enzymes representing the potential for oxidative phosphorylation, glucose phosphorylation, glycolysis, and lactate oxidation. In contrast, a reduced potential was observed in PAT for both fat oxidation (-20%) and high-energy phosphate transfer (-38%). For excitation-contraction coupling, PAT had a compromised sarcoplasmic reticulum maximal Ca-ATPase activity (-21%), Ca uptake (-44%), and sarcoplasmic endopleasmic reticulum (SERCA) expression for both SERCA1a (-16%) and SERCA2a (-17%), which were accompanied by a lower phase 2 Ca release (-45%). The Na-K-ATPase concentration, the enzyme-regulating membrane excitability via active Na and K seemed elevated (+25%) in PAT. CONCLUSIONS: These results demonstrate the feasibility of analyzing tissue samples for a wide range of properties and provide a rationale for studies examining the cellular basis of myalgia with particular emphasis on sarcoplasmic reticulum Ca cycling, given the latter's role in regulating a wide range of cellular functions.
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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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".