BACKGROUND Transitioning from whole blood (WB) to components developed from efforts to maximize donor yield. Components are advantageous for specific derangements, but treating hemorrhage with components requires significantly more volume to provide similar effects to WB. Because storage lesion and waste remain problematic, this study examined hemostatic function of refrigerated WB stored for 35 days in anticoagulants citrate–phosphate‐dextrose‐adenosine (CPDA‐1), citrate–phosphate‐dextrose (CPD), or citrate–phosphate‐double dextrose (CP2D). METHODS Refrigerated WB units from healthy donors were sampled over 35 days. Global hemostatic parameters were measured by thromboelastometry, thrombogram, platelet aggregometry, and platelet adhesion to collagen under shear conditions. The effects of transfusion filtration and mixing 35‐day stored product with fresh WB were evaluated. RESULTS Countable platelets declined as aggregation clusters appeared in microscopy. While gross platelet agonist‐induced aggregation declined over time, normalization revealed aggregation responses in remaining platelets. Peak thrombin generation increased over time. Clot strength diminished over storage in tissue factor–activated samples (normalized by filtration of aggregates). Functional fibrinogen responses remained consistent throughout. Filtration was necessary to maintain consistent platelet adhesion to collagen beyond collection day. Few differences were observed between anticoagulants, and stored/fresh mixing studies normalized coagulation parameters. CONCLUSIONS WB is easier to collect, store, and transfuse. WB provides platelets, an oft‐neglected, critical resuscitation component, but their individual numbers decline as aggregates appear, resulting in diminished coagulation response. WB has better performance in these assays when examined at earlier time points, but expirations designated to specific anticoagulants appear arbitrary for hemostatic functionality, as little changes beyond 21 days regardless of anticoagulant.

The infection of Escherichia coli cells by bacteriophage lambda results in bifurcated means of propagation, where the phage decides between the lytic and lysogenic pathways. Although traditionally thought to be mutually exclusive, increasing evidence suggests that this lysis‐lysogeny decision is more complex than once believed, but exploring its intricacies requires an improved resolution of study. Here, with a newly developed fluorescent reporter system labeling single phage and E. coli DNAs, these two distinct pathways can be visualized by following the DNA movements in vivo. Surprisingly, we frequently observed an interesting “lyso‐lysis” phenomenon in lytic cells, where phage integrates its DNA into the host, a characteristic event of the lysogenic pathway, followed by cell lysis. Furthermore, the frequency of lyso‐lysis increases with the number of infecting phages, and specifically, with CII activity. Moreover, in lytic cells, the integration site attB on the E. coli genome migrates toward the polar region over time, leading to more spatial overlap with the phage DNA and frequent colocalization/collision of attB and phage DNA, possibly contributing to a higher chance for DNA integration.

Background: Platelets pose the greatest transfusion-transmitted infectious risk among blood products. Refrigeration of platelets can mitigate bacterial contamination and extend platelet shelf life. Implementation of pathogen reduction technologies (PRTs) at blood banks has become increasingly popular to protect against emerging and reemerging infectious diseases. In this study, we sought to evaluate the effects of Intercept PRT on platelets collected on different platforms and cold-stored for up to 21 days in plasma and platelet additive solution (PAS). Methods: Double-dose apheresis platelets were collected with use of a Trima or Amicus system into either 100% plasma or 65% InterSol PAS/35% plasma and split equally between two bags. One bag served as control, while the other received Intercept PRT treatment. Bags were stored unagitated in the cold and evaluated on Days 1, 7, 14, and 21 to assess platelet metabolism, activation, aggregation, and clot formation and retraction. Results: By Day 14 of storage, lactate levels reached approximately 13 mmol/L for all samples irrespective of Intercept treatment. Mean clot firmness dropped from the 62.2-to 67.5-mm range (Day 1) to the 28.4-to 51.3-mm range (Day 21), with no differences observed between groups. Clot weights of Intercepttreated Trima/plasma samples were significantly higher than control by Day 14 of storage (P = .004), indicating a reduced clot retraction function. Intercept treatment caused a higher incidence of plasma membrane breakdown in plasma-stored platelets (P = .0013; Trima/plasma Day 14 Control vs Intercept). Conclusions: Intercept treatment of platelets and subsequent cold storage, in plasma or PAS, results in comparable platelet metabolism platelets for up to 14 days of storage but altered clotting dynamics. Pathogen-reduced platelets with an extended shelf life would be beneficial for the deployed setting and would greatly impact transfusion practice among civilian transfusion centers.

Diagnostic test, level III.

BACKGROUND Cryoprecipitate's shelf life is limited due to concerns over decreased clotting factor activity and contamination with extended storage. Hemostatic characteristics of thawed cryoprecipitate stored up to 35 days at refrigerated and room temperatures were assessed. STUDY DESIGN AND METHODS Pooled cryoprecipitate was thawed and aliquoted for storage at 1–6°C or 21–24°C. Samples were tested immediately after thawing and at 4 h, 24 h, 72 h, and weekly for 35 days. At each time point fibrinogen, factor VIII (FVIII), and von Willebrand factor (vWF) were assessed. Thrombin generation and rotational thromboelastometry (ROTEM) were also performed. Further, packed red cells, platelet concentrates, frozen plasma, and stored cryoprecipitate were combined (1:1:1:1) to simulate massive transfusion and analyzed by ROTEM. Day 35 samples were cultured for bacterial contamination. RESULTS Precipitation was observed in refrigerated samples; however, these aggregates were easily resuspended upon warming in a 37°C water bath. No significant changes were observed in fibrinogen concentration or ROTEM at either temperature. FVIII and vWF declined significantly during storage. vWF, clot time, and thrombin generation were significantly better preserved with refrigeration. With simulated massive transfusion, fibrinogen function remained at or above the established range for whole blood at both storage temperatures. Bacterial contamination was not observed in cold stored or room temperature cryoprecipitate. CONCLUSION The fibrinogen concentration and function of cryoprecipitate at extended storage durations are adequate for fibrinogen replacement in critical bleeding. These results support extension of the shelf life of cryoprecipitate when used for fibrinogen replacement.

BACKGROUND Current limitations of platelet shelf life to 5 days have led to an increasingly greater demand for hemostatic agents with greater longevity. The objective of this study was to evaluate the function of a lyophilized platelet‐derived hemostatic product (thrombosome [TS]) as a potential alternative to fresh platelets. METHODS Platelets were collected from whole blood from healthy donors. TSs were reconstituted with water and added to various configurations of reassembled whole blood (platelets, plasma, and RBCs); measures included rotational thromboelastometry (ROTEM), optical aggregometry, mitochondrial function, calibrated automated thrombogram, collagen adhesion under flow (shear flow assay), and flow cytometry. RESULTS In ROTEM, no differences were observed between maximum clot formation values for contact pathway activation thromboelastometry tests with TSs or platelet samples. Significantly decreased aggregation was observed in the TSs versus platelets (p < 0.001 for all agonists). Flow cytometry measures demonstrated significant decreases in glycoprotein Ib expression and increases in phosphatidylserine expression in the TS group (p < 0.01). The calibrated automated thrombogram assay was suggestive (lag time and peak thrombin) that the TSs might have some thrombogenic properties. Measurements of mitochondrial function revealed that TSs had no functional mitochondria. CONCLUSION In this study, TSs were shown to have nonfunctional mitochondria. ROTEM measures revealed that the TSs had no impact on clot strength. Likewise, compared to platelets, the TSs displayed minimal aggregation, had significantly more phosphatidylserine (measure of activation status), but had the ability to adhere to a collagen surface under flow conditions and contribute to clot formation and induced greater thrombin generation.

BACKGROUND: Dried plasmas can overcome logistical barriers that prevent fresh frozen plasma (FFP) usage in acute resuscitation, but processing of these products can detrimentally alter the composition. Spraydried plasma (SpDP) from single units is deficient in high-molecular-weight multimers of von Willebrand factor (vWF), a critical facilitator of platelet adhesion and thrombus formation. We hypothesized that converting high-molecular-weight multimers to smaller-molecularweight multimers would retain vWF's capacity to mediate platelet adhesion.STUDY DESIGN AND METHODS: SpDP obtained from untreated FFP was reconstituted with glycinehydrochloric acid (HCl) and glycine (20 mM:50 mM) or pretreated with glycine-HCl (20 mM) or glycine-glycine-HCl (20 mM:50 mM) and reconstituted with water. In vitro hemostatic potential of SpDPs versus FFP or FFP spiked with 70 mM of glycine was evaluated, leading to a more detailed in vitro study of glycine-HCl-glycine (20 mM:50 mM) pretreated SpDP. Plasmas were combined with RBCs and platelets to observe global coagulation response. RESULTS:While vWF-ristocetin cofactor activity is significantly decreased (−41.13%; p < .0001) in SpDP, a model of vWF-mediated platelet adhesion to collagen under flow showed enhanced function (+13%; p < .01). Fewer microparticles, particularly of platelet origin, were observed in SpDP versus FFP (p < .0001). Small but significant differences in thromboelastography results were observed, although SpDP and FFP were within normal ranges. CONCLUSION: Comparable coagulability wasobserved in FFP and SpDP. The apparent paradox between vWF-ristocetin cofactor assay and vWF-mediated platelet adhesion may be explained by the increase in smaller multimers of vWF in SpDP, producing different outcomes in these assays.

Background Never frozen liquid plasma (LP) has limited shelf life versus fresh frozen plasma (FFP) or plasma frozen within 24 h (PF24). Previous studies showed decreasing factor activities after Day (D)14 in thawed FFP but no differences between LP and FFP until D10. This study examined LP function through D40. Study design and methods FFP and PF24 were stored at −20°C until assaying. LP was assayed on D5 then stored (4°C) for testing through D40. A clinical coagulation analyzer measured Factor (F)V, FVIII, fibrinogen, prothrombin time (PT), and activated partial thromboplastin time (aPTT). Thromboelastography (TEG) and thrombogram measured functional coagulation. Ristocetin cofactor assay quantified von Willebrand factor (vWF) activity. Residual platelets were counted. Results FV/FVIII showed diminished activity over time in LP, while PT and aPTT both increased over time. LP vWF declined significantly by D7. Fibrinogen remained high through D40. Thrombin lagtime was delayed in LP but consistent to D40, while peak thrombin was significantly lower in LP but did not significantly decline over time. TEG R‐time and angle remained constant. LP and PF24 (with residual platelets) had initially higher TEG maximum amplitudes (MA), but by D14 LP was similar to FFP. Conclusion Despite significant declines in some factors in D40 LP, fibrinogen concentration and TEG MA were stable suggesting stored LP provides fibrinogen similarly to frozen plasmas even at D40. LP is easier to store and prepare for prehospital transfusion, important benefits when the alternative is crystalloid.