Use of Plasma with High Levels of lonised Calcium in the Production of Model Scale Goagulation Factor Concentrates

Farrugia, Albert; Douglas, S.; James, J.; Whyte, Gordon; Herrington, R.W.

doi:10.1055/s-0038-1647322

Cited by 10 publications

(10 citation statements)

References 12 publications

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“…It is important to note that citrate chelates Ca 2+ and Mg 2+ equally and incompletely, and that, at the citrate concentration used here, ≈30–70 μmol/l Ca 2+ should remain (Farrugia et al , 1990; Rebello et al , 2000) and, thus, about 25 μmol/l Mg 2+ . Binding to P‐selectin is Ca 2+ ‐dependent and optimal around 100 μmol/l for isolated leucocytes (Geng et al , 1992).…”

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confidence: 84%

Characteristics of leucocyte adhesion directly observed in flowing whole blood in vitro

Abbitt

Nash

2001

Br J Haematol

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Use of whole blood in adhesion assays allows analysis of the rheological and haematological factors that may influence adhesion, and avoids the need for isolation procedures that may modify the properties of leucocytes. We have adapted an in vitro flow model to allow videomicroscopy of leucocytes fluorescently labelled with rhodamine 6G (20 microg/ml) in anticoagulated whole blood. Blood was perfused at a range of wall shear rates (35-280/s) through a vertical glass capillary with a rectangular cross-section (microslide) that had been coated with P-selectin (10 microg/ml). Nearly all adherent cells were rolling in blood that had been anticoagulated with buffered citrate, but 40-50% became immobilized when heparin or thrombin inhibitor (PPACK) were used. The efficiency of leucocyte adhesion decreased steadily during 1-4 h of blood storage. Smaller fluorescent cells (lymphocytes) adhered less efficiently than larger cells (granulocytes) and rolled faster. Adhesion decreased monotonically with increasing wall shear rate or stress, but the velocity of rolling varied little. Among healthy volunteer donors, adhesion correlated with blood leucocyte count, but did not vary significantly with natural variation in haematocrit, blood viscosity or red cell aggregation. In conclusion, we have characterized adhesion of leucocytes in flowing whole blood, identified key experimental variables and demonstrated that physical environmental factors can markedly influence adhesive behaviour.

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confidence: 84%

Characteristics of leucocyte adhesion directly observed in flowing whole blood in vitro

Abbitt

Nash

2001

Br J Haematol

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“…enhancement in FVIII recovery is attributed to the fact that heparin maintains physiologic levels of calcium, which is an integral part of the FVIII molecule and important for its stability (Rock et al, 1979(Rock et al, , 1983Morgenthaler, Zuber & Friedli, 1985). Chelation of the calcium decreases the activity of FVIII that is not bound to vWF (Mikaelsson, Forsman & Oswaldsson, 1983;Rock et al, 1983;Farrugia et al, 1990). Also, in the presence of citrate, FVIII coagulant activity decreases during storage in a biphasic manner (Mikaelsson, Forsman & Oswaldsson, 1983) while collection of blood in heparin renders FVIII coagulant activity noticeably stable for at least 24 h (Krachmalnicoff & Thomas, 1983;Smit Sibinga et al, 1984;Morgenthaler, Zuber & Friedli, 1985;Cumming, Wensley & Delamore, 1986).…”

Section: Discussionmentioning

confidence: 99%

Cryoprecipitate production: the use of additives to enhance the yield

Yousef

Neurath

Freedman

et al. 2006

Clinical &Amp; Laboratory Haematology

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Cryoprecipitate is still widely used to treat hemophilia A in developing countries. However, the yield of factor VIII is relatively low averaging, i.e. only 50%. We have attempted to enhance the yield by adding sodium citrate to the plasma following the method of Shanbrom and Owens (Blood 98, 2001, 60a). Fresh-frozen plasma (FFP) units were processed either as control plasma or after the addition of 10% sodium citrate. Cryoprecipitate was produced from both. After resuspension, calcium chloride was added to the citrated cryoprecipitate to correct for excess citrate prior to testing. The levels of FVIII and fibrinogen were determined in both preparations. The citrated cryoprecipitates had varying yields of fibrinogen and FVIII in the cryoprecipitate. The FVIII levels varied from 34% to 215% recovery. Fibrinogen ranged from 55.5% to 121.4%. We found that the addition of increasing amounts of CaCl2 to normal plasma raised the FVIII values from 1.0 to 4 U/ml. To determine the possibility of assay influence we added different quantities of CaCl2 to control plasma and measured the FVIII and activated partial thromboplastin time levels. Addition of citrate to plasma resulted in an increased total amount of cryoprecipitate much of which was citrate. Assays showed considerable ranges in the quantity of FVIII and fibrinogen. Activation of FVIII can be caused by addition of excess calcium.

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“…Factor VIII recoveries in cryoprecipitates prepared by fast-thaw and thaw siphon techniques or combined fast-thaw/thaw siphon techniques were improved by 20, 83 and 52%, re spectively, in 18-but not 3-hour old plasmas compared to standard citrate anticoagulated plasma. In studies by Farrugia et al [18], plasma recovered from full-and half strength CPD anticoagulant was initially frozen in liquid nitrogen and stored at -30 °C until cryoprecipitated using a stirred and heated vessel maintained at 0-2 °C. Factor VIITC yields were approximately 20% higher in half strength CPD plasma stored up to 6 h prior to freezing.…”

Section: Discussionmentioning

confidence: 99%

“…The absence of fibrinopeptide-A generation [21,22] and the lack of effect of the thrombin inhibitors PPACK [23] and hirudin [24] on SP formation indicated that the process was thrombin-independent. However, SP forma tion was found to be associated with a reduction in the fibrinogen concentration of the thawed plasmas and the Palmer/Rosborough/Perkins/Bolton/ Rock/Ganz Heparinized Plasma Storage 268 [3,18,[57][58][59][60] used in order to preserve or restore and stabilize factor VIII activity. This study suggests that inhi bition of the generation of activated factor XIII or its effects on fibrinogen cross-linking has the potential for further improving factor VIII yields in such plasmas even under commercial freezing and storage conditions.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Factors Affecting the Stability of Frozen Heparinized Plasma

Palmer¹,

Rosborough²,

Perkins³

et al. 1993

Vox Sanguinis

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The use of heparin rather than citrate as primary anticoagulant has been shown to significantly improve the initial activity, stability and recovery of factor VIII:C from human plasma, cryoprecipitates or factor VIII concentrates if the plasma was initially frozen at -80°C and subsequently stored at this temperature. If frozen and stored at progressively warmer temperatures however, increasing amounts of insoluble protein aggregates, termed storage precipitates (SPs), were recovered in the thawed plasma and cryoprecipitate fractions. Plasma recovery by centrifugation at 7,000 g for 7 min [Method I (MI)], 2 x 10 min (MII) or 15 min (MIII) had little effect on SP formation after 1 month at any storage temperature. After 4 months at -20°C, more SP was recovered from MI plasma whereas at -40°C, more SP was recovered from MI plasma. Also, the preparation method had little or no effect on factor VIII:C activity at equivalent storage times or temperatures. A trend towards improved factor VIII recoveries was noted at lower freezing and storage temperatures however. SP formation was associated with reduced fibrinogen levels in the recovered plasma without loss of antithrombin-III or increased fibrinopeptide-A. Western blots showed polymerization of Aa or y-chains of fibrinogen. SP formation was reduced or eliminated with factor XIII inhibitors , antibody to the active factor XIII a subunit or adjustment of heparinized plasma to 5-10 mM sodium citrate before initial freezing and storage. Although plasma factor VIII:C recoveries were only slightly affected at these citrate concentrations under most conditions, its recovery in cryoprecipitates was substantially improved owing to the reduction or absence of SPs.

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Use of Plasma with High Levels of lonised Calcium in the Production of Model Scale Goagulation Factor Concentrates

Cited by 10 publications

References 12 publications

Characteristics of leucocyte adhesion directly observed in flowing whole blood in vitro

Characteristics of leucocyte adhesion directly observed in flowing whole blood in vitro

Cryoprecipitate production: the use of additives to enhance the yield

Characterization of Factors Affecting the Stability of Frozen Heparinized Plasma

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