Cord Blood Storage Following Collection: Impact on Volume Reduction and Cryopreservation
Bibliographic record
Abstract
Delays from cord blood (CB) collection to processing and cryopreservation vary among CB banks and optimal CB storage length and conditions are still poorly defined. Only about 25% of the collected CB units contain a total nucleated cell (TNC) content ≥1 × 109, providing enough cells to transplant a 40 kg recipient. Our preliminary results suggest that CB is best stored at 4°C for up to 3 days without significant losses in cell numbers and viability. We tested whether pre-cryopreservation CB storage conditions impact cell recovery and viability after processing and cryopreservation. CB units were collected and processed and cryopreserved either on the day of collection (day 0) or after a 3-day storage at 4°C or room temperature (RT). They were volume-reduced by buffy coat separation (Optipress II) or red cell sedimentation (Hespan). Processed CB units were cryopreserved and stored for 1 month before thawing and washing, and were assessed for TNC, mononucleated cell (MNC) and CD34+ cell recovery, and CD45+ and CD34+ cell viability. Storage at RT for 3 days induced a significant loss in TNC and MNC after processing whereas storage at 4°C did not induce a significant change compared to units processed on day 0. Both Optipress II- and Hespan-processed CB units showed low CD45+ cell viabilities when stored at RT (e.g. 64 ± 10% at RT and 82 ± 8% at 4°C vs 98 ± 2% on day 0, p<0.002 vs day 0 for the Optipress group). Interestingly, CB units stored at RT for 3 days showed reduced TNC, MNC and CD34+ cell recoveries and reduced CD34+ cell viability upon thawing and washing compared to units cryopreserved on day 0 or stored at 4°C for 3 days (e.g. CD34+ cell viability in the Optipress group: 70 ± 14% at RT, 87 ± 10% at 4°C vs 84 ± 5% on day 0, p<0,03 vs day 0). These results indicate that prolonged storage at RT prior to cryopreservation can negatively impact CB cell recovery and viability after processing and upon thawing and washing of cryopreserved units.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".