Transient Warming Events in Cord Blood Units and the Impact on Product Quality
Bibliographic record
Abstract
Transient warming events (TWE) are brief exposures of a cryopreserved product to temperatures above the critical storage temperature. Cord blood units (CBUs) are routinely stored in liquid nitrogen at –196°C. The viability and potency of CBUs may be reduced because of TWEs during operational activities. Ultimately, this loss of viability and potency may affect the clinical effectiveness of CBU transplants. A TWE study was conducted that consisted of three phases; first, the kinetics of transient warming to 0°C were studied using temperature probes on CBU bags. Second, the processing time to reach an allowable (−135°C) and deviant (−120°C) temperature in the CBU was determined based on (a) phase I kinetic data and (b) an assessment of ambient room temperature and exposure durations during operational activities. Third, a pool and split study was performed to assess the effect of TWE scenarios in CBU post-thaw quality criteria (CD45+ and CD34+ cell viability and recovery, colony-forming unit [CFU] growth). Kinetic and operational data supported our selections for the warming scenarios; the 5-ml compartment warmed faster than the 20-ml compartment, taking a minimum of 130 seconds to reach –135°C and a minimum of 176 seconds to reach −120°C. The post-thaw data showed that warming events can affect the quality of the CBU, with several significant differences between the control and either the typical TWE scenario (5 ml bag CD45+ viability [p = .0469], CD45+ yield [p = .0406], and CFU-GM [p = .0388]) or worst case TWE scenario (20 ml CFU-total yield [p = .0205], 5 ml CFU-GM yield [p = .0388]). All segment samples met CD34+ and CFU potency criteria but several segment samples failed to meet requirements for CD45+ viability. Transient warming events were shown to affect product quality, but the effects were small for the scenarios tested and, while in some cases the segments failed to meet quality thresholds, the results in the 5 ml and 20 ml bag compartments met our post-thaw acceptance criteria. Therefore, efforts should be taken to establish critical processing constraints for CBB to minimize the impact of TWE on product quality.
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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 | 0.001 | 0.002 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".