A three-step method for preparing cryopreserved samples of apheresis products for post-thaw analysis yields a high recovery of viable cells.

Flow cytometry protocols for counting fresh CD34+ cell samples are not ideal for cryopreserved products due to cryoprotectant cytotoxicity. For cryopreserved samples, often large volumes of hypotonic solutions, which can cause cell death, are used to remove the cryoprotectant with a post-thaw wash. We recently developed a novel multistep dilution method with subsequent flow cytometry analysis to allow for accurate and reproducible results. The previous method involved washing steps which invalidate the ability to enumerate cell recovery, and success had to be gauged solely on viability. The new method allows for assessment of total cell recovery and viable cell recovery. Apheresis products were cryopreserved in 10% DMSO at a target WBC concentration of 300 × 106/mL. Cryovials from these products were thawed at 37°C, and samples were diluted 1:2 by three additions of 1/3 sample volume using 1%-Human Albumin in Dextran 40 (10% Low Molecular Weight Dextran in 0.9% NaCl) separated by 5 min between each addition. A 1:10 dilution was performed to obtain the correct cell concentration for flow cytometric analysis resulting in a 1:20 dilution. End WBC concentrations were ~15 × 106/mL with DMSO diluted to 0.5%. Fifty-two samples were tested with this new method. Total and viable cell recoveries were calculated based on pre-cryopreservation data. Median total cell recoveries for CD34 and CD3 were >85%, while median viable cell recoveries were >75%. Cryopreserved samples can be reliably prepared for flow cytometric testing using a step-wise dilution to preserve cell integrity and robust recoveries.

被引量：- 发表：1970

High-frequency whole blood donation and its impact on mortality: Evidence from a data linkage study in Australia.

Previous reports suggest that blood donors have a lower mortality risk, which may partially reflect the "healthy donor effect" (HDE). HDE arises in donors due to selection bias and confounding if not appropriately addressed. Using the Sax Institute's 45 and Up Study data linked with blood donation history, we used a "5-year exposure window" method to select donors into regular high-frequency whole blood (WB)donors (at least two donations per exposure year) and low-frequency donors (remaining donors) with an active donation career of 5 years. To further reduce the confounding, we used statistical approaches like the inverse probability weighted (IPW) marginal structural model and the doubly robust targeted minimum loss-based estimator (TMLE), which incorporated machine learning algorithms and time-varying analyses. We selected 4750 (64.7%) low-frequency and 2588 (35.3%) high-frequency donors in the analyses. A total of 69 (1.5%) from the low-frequency and 45 (1.7%) donors from the regular high-frequency group died during the 7-year follow-up period. We did not find any statistically significant association between regular high-frequency blood donation and mortality (IPW RR = 0.98 95% CI 0.68, 1.28). TMLE model also showed similar results to IPW (RR = 0.97 95% CI 0.80, 1.16). Time-varying TMLE did not find any significant association between high-frequency donation and all-cause mortality either (RR = 0.98 95% 0.74, 1.29). We did not find a significant association between regular high-frequency WB donation and all-cause mortality when appropriate methods were employed to minimize the HDE.

被引量：- 发表：1970

Impact of elevated direct factor Xa inhibitor plasma levels on perioperative blood loss in patients undergoing urgent surgery.

被引量：- 发表：1970

The power of arts-based film interventions to encourage Black blood donors.

被引量：- 发表：1970

Challenges in reliable preoperative blood ordering: A qualitative interview study.

被引量：- 发表：1970