Enhanced methods for needle biopsy and cryopreservation of skeletal muscle in older adults
Bibliographic record
Abstract
Abstract Background Human muscle biopsies are increasingly important for diagnosis, research, and to monitor therapeutic trials. We examined the use of a self-contained, vacuum-assisted biopsy system and a novel muscle freezing technique to improve, simplify, and standardize human muscle biopsy collection and cryopreservation in older adults. Methods The Vacora vacuum-assisted biopsy system was deployed in muscle biopsies of 12 individuals ranging in age from 57 to 80 years. This office-based approach was well tolerated as it is minimally invasive, uses only local anesthetic, and has a quick recovery. To maximize biopsy sample quality and reproducibility, we developed a novel muscle sample freezing protocol. Fresh human and mouse muscle biopsy samples were placed into readily available tissue cassettes followed by direct freezing in liquid nitrogen. After this modified snap freezing protocol, frozen muscle samples were enrobed in OCT for cryosectioning. We examined the effect of this freezing approach in histological sections of rodent and human muscle samples. ResultsThe Vacora Biopsy System provided as many as four skeletal muscle core samples from a single biopsy site. Biopsy samples from 12 older adults weighed an average of 147.5 ± 11 mg each and had a consistent size and shape. There were no complications, and the residual scar is less than 1cm. The freezing method using standard tissue cassettes with direct freezing in liquid nitrogen yielded high quality cryopreserved muscle tissue suitable for histological analysis without the need for isopentane and with little to no freeze-thaw damage. Conclusions These enhancements have streamlined and improved the consistency of our muscle biopsy protocol and provide sufficient high-quality sample for multi-dimensional downstream studies of human muscle in aging and disease.
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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 | 0.008 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| 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".