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P F van der Meer

Publications and source records attributed to P F van der Meer.

At least 19 recordsLinked to original sources
PubMed2007

Sterilization method of platelet storage containers affects in vitro parameters.

BACKGROUND AND AIM: Four butyryl trihexyl phthalate plasticized polyvinyl chloride (BTHC-PVC) containers were compared for storage of leukoreduced platelet concentrates (LR-PC): three ethylene oxide (EtO) sterilized (Gambro, Haemonetics, Fresenius), and one steam-sterilized (Fresenius). METHODS: LR-PCs were made from 5 buffy coats and 300 ml Composol additive solution, and leukoreduced by filtration. Four LR-PCs were pooled and subsequently divided over the 4 BTHC-PVC bags to prevent donor-dependent differences, and sampled for in vitro analysis on day 1, 2, 5, 7 and 9. RESULTS: The pH values on day 9 were (mean +/- SD, n = 10): 7.12 +/- 0.03 (Gambro), 7.12 +/- 0.04 (Haemonetics), and 7.07 +/- 0.09 (Fresenius, EtO-sterilized) (not significantly different), vs. 6.91 +/- 0.12 (Fresenius, steam-sterilized; P < 0.001 vs. all EtO-sterilized bags). LR-PCs stored in the steam-sterilized bag exhibited significantly higher glucose consumption and lactate production (P < 0.001 vs. all EtO-sterilized bags). CONCLUSION: All BTHC-PVC containers allow storage of LR-PCs for up to 9 days with good in vitro parameters. However, the method of sterilization affects the storage conditions of the LR-PCs in these bags.

Blood Platelets↗
PubMed2006

An evaluation of automated blood collection mixers.

BACKGROUND AND OBJECTIVES: We investigated the mixing capacity of two whole blood (WB) collection mixers. MATERIALS AND METHODS: WB was simulated by using a 25% glycerol solution warmed to 35 degrees C. Citrate-phosphate-dextrose (CPD) anticoagulant of a collection system was stained with toluidine blue, and simulated WB was added at 30, 60 or 90 ml/min, respectively (n = 3 per flow speed). The optical density (OD) of 10-ml fractions was measured, and results are expressed as percentage of a well-mixed '100%-sample'. RESULTS: CompoGuard showed adequate mixing at all three flow speeds (average ODs 96-103%). HemoLight showed good mixing at 60 and 90 ml/min (ODs from 97 to 101%). At 30 ml/min, mixing appeared suboptimal, but still conformed to our requirements with ODs from 96% to 104%. CONCLUSION: Both mixers give sufficient mixing of whole blood with anticoagulant.

Anticoagulants↗
PubMed2005

Interruption of agitation of platelet concentrates: effects on in vitro parameters.

BACKGROUND AND OBJECTIVES: When platelet concentrates (PCs) are shipped from one centre to another, they may remain unagitated for a considerable period of time. It was therefore our aim to study the effects of interruption of agitation on the in vitro parameters of PCs stored in platelet additive solutions. MATERIALS AND METHODS: In this multicentre study, PCs were prepared either by apheresis or from pooled buffy coats, paired to minimize donor-dependent differences, and aliquoted into 3 units with a 'low concentration' (approximately 1 x 10(9) platelets/ml; groups A, B and C) and 3 units with a 'high concentration' (approximately 2 x 10(9) platelets/ml; groups D, E and F). The final composition of the storage medium was 30% plasma and 70% additive solution in all PCs. Either PASIIIM or Composol was used as the additive solution. Agitation was interrupted for 2 days (between days 3 and 5, groups A and D), or for 4 days (between days 1 and 5, groups B and E), and continuous agitation served as the reference (groups C and F). A number of in vitro parameters were used for testing on days 1, 5 and 7. RESULTS: On day 7, reference units C and F in PASIIIM had significantly higher pH values than the study units in PASIIIM, but all retained a pH of > 6.5 at 37 degrees C. Hypotonic shock response (HSR) results were significantly lower in the high concentration/4-day interruption group (E) than in the other groups. The low-concentration groups in PASIIIM, with agitation interrupted for either 2 days (group A) or 4 days (group B), did not have HSR values significantly different from the respective references. Study groups A, B, D and E in Composol, a solution lacking phosphate, had a pH of approximately 6.5 on day 7, which was significantly lower than that of the references and of the corresponding units in PASIIIM. The pH values were > 7.0 in reference groups C and F in Composol, not significantly different from those in PASIIIM. HSR values were also significantly lower in the Composol study groups. On the other hand, the reference Composol groups showed results similar to units in PASIIIM. CONCLUSIONS: PCs in PASIIIM additive solution with a platelet concentration of approximately 1 x 10(9)/ml can sustain 4 days without agitation. Phosphate may be of importance in maintaining good in vitro characteristics during interruption of agitation.

Blood Platelets↗
PubMed2005

Interlaboratory comparison of red-cell ATP, 2,3-diphosphoglycerate and haemolysis measurements.

BACKGROUND AND OBJECTIVES: Red blood cell (RBC) storage systems are licensed based on their ability to prevent haemolysis and maintain RBC 24-h in vivo recovery. Preclinical testing includes measurement of RBC ATP as a surrogate for recovery, 2,3-diphosphoglycerate (DPG) as a surrogate for oxygen affinity, and free haemoglobin, which is indicative of red cell lysis. The reproducibility of RBC ATP, DPG and haemolysis measurements between centres was investigated. MATERIALS AND METHODS: Five, 4-day-old leucoreduced AS-1 RBC units were pooled, aliquotted and shipped on ice to 14 laboratories in the USA and European Union (EU). Each laboratory was to sample the bag twice on day 7 and measure RBC ATP, DPG, haemoglobin and haemolysis levels in triplicate on each sample. The variability of results was assessed by using coefficients of variation (CV) and analysis of variance. RESULTS: Measurements were highly reproducible at the individual sites. Between sites, the CV was 16% for ATP, 35% for DPG, 2% for total haemoglobin and 54% for haemolysis. For ATP and total haemoglobin, 94 and 80% of the variance in measurements was contributed by differences between sites, and more than 80% of the variance for DPG and haemolysis measurements came from markedly discordant results from three sites and one site, respectively. In descending order, mathematical errors, unvalidated analytical methods, a lack of shared standards and fluid handling errors contributed to the variability in measurements from different sites. CONCLUSIONS: While the methods used by laboratories engaged in RBC storage system clinical trials demonstrated good precision, differences in results between laboratories may hinder comparative analysis. Efforts to improve performance should focus on developing robust methods, especially for measuring RBC ATP.

2,3-Diphosphoglycerate↗
PubMed2005

Gamma irradiation does not affect 7-day storage of platelet concentrates.

BACKGROUND AND OBJECTIVES: Extension of storage of leucocyte-reduced platelet concentrates (LR-PCs) to 7 days has recently been introduced, but the effect of gamma irradiation on in vitro parameters was unknown. MATERIALS AND METHODS: A paired experiment was carried out, with gamma irradiation on day 1 or day 5 with 25 Gy, and no irradiation served as a reference. RESULTS: Measurements during storage up to 8 days after blood collection showed no significant differences of irradiated LR-PCs vs. the control. CONCLUSIONS: Irradiation, either on day 1 or day 5, had no effect on platelet quality during a 7-day storage period.

Blood Platelets↗
PubMed2004

Development of white blood cell fragments, during the preparation and storage of platelet concentrates, as measured by using real-time polymerase chain reaction.

BACKGROUND AND OBJECTIVES: White blood cell (WBC) fragments may cause human leucocyte antigen (HLA) immunization in recipients. We investigated the occurrence and production of WBC fragments in platelet concentrates (PCs) and plasma units, during storage and filtration, by using real-time polymerase chain reaction (PCR) and flow cytometry. MATERIALS AND METHODS: To study the occurrence of WBC fragments, 'male' WBCs were spiked into double-filtered 'female' PCs in a concentration series of 0.03-100 WBCs/microl (n = 4 per level). To study the production of WBC fragments, 'male' WBCs were spiked into 'female' plasma units to 4 x 10(9) WBCs/l and stored at room temperature prior to filtration (n = 4 per storage time; t = 0, 24 or 48 h). DNA was measured by both albumin real-time PCR and Y real-time PCR. Intact WBCs were counted by using flow cytometry. The number of WBC fragments was calculated by subtracting cell-free DNA (real-time PCR on supernatant) and intact WBCs (flow cytometry) from the total DNA amount (real-time PCR). RESULTS: Spiking of 'male' WBCs into 'female' PCs showed that the Y real-time PCR is linear and has a reproducible quantitative range down to 0.03 WBC/microl, but that the albumin-PCR, in unspiked samples, revealed a total of 6-10 WBC equivalents/microl (eq/microl). After centrifugation, half of this was observed as cell-free DNA in the supernatant, suggesting that the remaining DNA is derived from WBC fragments. The number of intact WBCs, amount of cell-free DNA and number of WBC fragments after filtration increased significantly when filtration was delayed for up to 48 h, from 0.1 WBC/microl, 1.3 WBC eq/microl and 0.6 WBC eq/microl at t = 0 h to 25 WBC/microl, 38 WBC eq/microl and 57 WBC eq/microl at t = 48 h, respectively. CONCLUSIONS: WBC fragments occur in WBC-reduced PCs and increase when products are stored, prior to filtration, up to levels that are equivalent to the amounts of intact WBCs that induce HLA immunization (i.e. > 5 x 10(6)/unit).

Blood Preservation↗
PubMed2003

Crossover study of three methods for low-level white blood cell counting on two types of flow cytometer.

BACKGROUND: Flow cytometric methods were previously shown to be preferable to microscopic and volumetric methods for counting residual white blood cells (WBCs). In this study, three flow cytometric, low-level WBC counting methods were cross compared using two flow cytometers. METHODS: Double-filtered red cell and platelet concentrates were spiked with different amounts of WBC to obtain panels of unspiked and 0.3, 1.0, 3.3, and 10.0 WBC/microl. The methods of BD Biosciences (BDB), Beckman-Coulter (BC), and an in-house method were performed on flow cytometers from BDB and BC. Samples were measured in ninefold. We required that (a) r(2) be at least 0.98 (linearity), (b) at least 80% of observations fell within 20% of expected values (accuracy), and (c) the coefficients of variation be at least 20% (precision) for samples containing at least 3.3 WBC/microl. RESULTS: For the red cell panel, our requirements were met by the BDB method on both flow cytometers and by the BC and in-house methods on the BDB flow cytometer only. For the platelet panel, our requirements were met on all combinations of methods and flow cytometers, except for the in-house method on the BDB flow cytometer. Intra-assay variation was lowest for the BDB method, irrespective of the type of flow cytometer used. CONCLUSION: Based on accuracy and precision, the BDB method on the BDB flow cytometer produced the best results for counting low-level WBCs.

Cell Separation↗
PubMed2003

Storage of platelets in additive solutions: a multicentre study of the in vitro effects of potassium and magnesium.

BACKGROUND AND OBJECTIVES: In a preliminary study, the presence of potassium and magnesium in a modified synthetic medium (PAS-III) was found to have a significant influence on platelet metabolism (using apheresis-derived, as well as buffy-coat-derived platelets) when compared with standard PAS-III. The differences included reduced glycolysis, as evidenced by lower consumption of glucose and lower production of lactate, but also better preservation of pH and hypotonic shock response reactivity. The results suggested that storage in modified PAS-III containing 20% plasma was comparable to storage in standard PAS-III containing 30% plasma. To confirm the preliminary results and to evaluate the effects of different preparation protocols, an international multicentre study, which included 11 different sites, was conducted. MATERIALS AND METHODS: Platelets from 30 pools of approximately 20 buffy coat (BC) units each and 24 pooled apheresis platelet units were aliquoted for storage in plasma (reference) or synthetic medium using either a specific additive solution (PAS-III) containing 30% plasma or a modification of PAS-III containing 5.0 mm potassium and 1.5 mm magnesium (PAS-IIIM) and either 30% or 20% plasma. Units were stored at room temperature with agitation for 7 days during which in vitro testing was carried out for biochemical, haematological and functional parameters. RESULTS: Storage of platelets in PAS-IIIM resulted in a reduction in the rate of glycolysis and better retention of pH and hypotonic shock response reactivity. Storage in PAS-IIIM containing 20% plasma appeared to result in the retention of in vitro properties, similar to those observed during storage in standard PAS-III containing 30% plasma. CONCLUSIONS: The results of this study confirm the preliminary results. Similar results were seen with platelets prepared by BC and apheresis methods, despite differences in equipment, the preparation technique and in the final platelet contents achieved in the platelet units. Storage of platelets in PAS-IIIM should be considered to improve platelet function and allow plasma reduction to 20%.

Blood Component Removal↗
PubMed2003

Comparison of various dimethylsulphoxide-containing solutions for cryopreservation of leucoreduced platelet concentrates.

BACKGROUND AND OBJECTIVES: Leucoreduced platelet concentrates (LR-PCs) can be stored at 20-24 degrees C for 5-7 days. When LR-PCs are cryopreserved they can be stored for several years. For cryopreservation to become applicable in blood-bank practice, an off-the-shelf cryoprotectant is needed that can be added to the LR-PC in a sterile manner. For this, we varied the composition of the cryopreservation medium and studied various parameters of cryopreserved LR-PCs for up to 24 h after thawing at room temperature. MATERIALS AND METHODS: LR-PCs in plasma or Composol were concentrated and divided into 2 units. To each unit, an equal part of 10% dimethylsulfoxide (DMSO) in plasma, Composol with or without 5% albumin, or GPO (pasteurized plasma-protein solution) was added. Freezing occurred at 1 degrees C/min and LR-PCs were placed in the vapour phase of nitrogen. LR-PCs were thawed at 37 degrees C and stored at room temperature. LR-PCs were tested for morphology, platelet recovery, swirling effect, and activation antigens at various time-points thereafter. RESULTS: LR-PCs in 100%, 65% and 50% plasma supplemented with Composol showed good morphology scores (>250), limited CD62P expression (<35%), low CD63 expression (<20%) and a swirling effect of about 2, at 24 h after thawing. At the same time-point, platelet recovery was >80% under all conditions and CD42b expression varied between 70 and 85%. Results of LR-PCs in 15% plasma and Composol, with or without plasma substitutes, were not acceptable at 24 h after thawing, i.e. the morphology score was <200 and the CD62P expression was >40%. CONCLUSIONS: A minimum of 50% plasma in the cryopreserved LR-PC is necessary to maintain an acceptable in vitro quality of platelets up to 24 h after thawing. Composol is a good candidate for using to prepare an off-the-shelf cryoprotectant.

Blood Platelets↗
PubMed2001

Comparison of five platforms for enumeration of residual leucocytes in leucoreduced blood components.

The need for quality control of leucoreduction of blood products has led to the development of various methods to count low levels of residual leucocytes. We compared five platforms side-by-side: the Nageotte haemocytometer and four based on fluorescent staining of nuclei: two flowcytometers (Beckman Coulter, BD Biosciences) with methods based on counting beads, a volumetric flow cytometer (Partec) and the microvolumic fluorimeter ImagN2000 (BD Biosciences), all according to their manufacturers' recommended methods. Analysis of double-filtered red cell concentrates (RCCs) and platelet concentrates (PCs), spiked with various numbers of leucocytes, revealed good linearity for all methods over the range of 1.6-32.7 leucocytes/microl, all with r(2) > 0.99. At the rejection level of leucocyte-reduced blood components, i.e. 1 x 10(6) per unit corresponding with approximately 3.3 leucocytes/microl, the Nageotte haemocytometer had low accuracy (0% for RCCs, 56% for PCs), and was relatively imprecise [coefficient of variance (CV) of 34% and 30% respectively]. The Partec flow cytometer gave good results for RCCs (accuracy 67%, CV 22%), but not for PCs (accuracy 0%, CV 25%). The ImagN2000 had an accuracy of 44% for RCCs and 89% for PCs, but the precision was variable (CV 32% for RCCs, 15% for PCs). The best results were obtained with the Beckman Coulter (RCCs: accuracy 86%, CV 13%, PCs: accuracy 67%, CV 16%), and BD Biosciences platforms (RCCs: accuracy 100%, CV 10%; PCs: accuracy 89%, CV 11%). We conclude that, at the rejection level of 1 x 10(6) leucocytes per unit, the widely used Nageotte haemocytometer performs poorly in terms of inaccuracy and imprecision, and that both counting-bead-based, flow cytometric methods performed best.

Flow Cytometry↗
PubMed2001

Variation of pH-measurement in platelet concentrates.

To measure pH in platelet concentrates, blood gas analysers with different calibration principles may be used. In this study, variances observed in pH measurements with two types of blood gas analysers were investigated. pH was measured in crystalloid solutions (platelet additive solution (PAS-II), phosphate-buffered solutions) and two types of platelet concentrates (containing 100% plasma, or 65% PAS-II/35% plasma) with two blood gas analysers: either using liquid and gas calibration (AVL 945), or only liquid calibration (AVL OMNI). These measurements were compared with a reference method. Especially for PAS-II, large variation in pH was observed between AVL 945, AVL OMNI and the reference method: 6.91 +/- 0.02, 7.35 +/- 0.02 and 7.188 +/- 0.010, respectively (mean +/- SD; n = 12, P < 0.0001, paired t-test). A significant difference in pH was also found for platelet concentrates in 65% PAS/35% plasma (6.88 +/- 0.09 on AVL 945 and 7.02 +/- 0.09 on AVL OMNI, n = 134, P < 0.0001). Comparison with the reference method revealed minor differences with AVL 945, whereas AVL OMNI gave a mean difference in pH of + 0.17. Platelets in 100% plasma revealed smaller differences (6.93 +/- 0.13 for AVL 945 and 6.99 +/- 0.13 for AVL OMNI, n = 95, P < 0.0001). We conclude that different blood gas analysers can yield different pH values, especially in weak buffered solutions such as platelet concentrates in PAS-II. Validation of blood gas analysers for pH measurement of these solutions is therefore mandatory.

Blood Gas Analysis↗
PubMed2001

Comparison of two platelet additive solutions.

The use of an additive solution for substitution of plasma for storage of leukodepleted platelet concentrates can have many advantages. In this study, a comparison was made between two platelet additive solutions: one containing citrate and acetate (PAS-II), the other also supplemented with additional salts such as magnesium, and with gluconate (Composol-PS). Donor-dependent differences were avoided by applying a paired experimental design (n = 10). The platelet concentrates were prepared by pooling five buffy coats and the additive solution, and prestorage filtration was utilized to remove leucocytes to well below 1 x 106. Storage of platelet concentrates up to 9 days after blood collection revealed that platelet concentrates in Composol-PS maintained an almost constant pH of on average 6.93 from day 2 through day 7, and at 6.90 at day 9. This was in contrast to PAS-II, which showed a gradually decreasing pH from on average 6.97 at day 1 to 6.86 at day 9. In all units stored in both solutions the swirling effect was present during 9 days of storage. In conclusion, both additive solutions allow storage of platelets, derived from pooled buffy coats, for up to 9 days after collection of the whole blood, with maintenance of good quality in vitro. Composol-PS has a slightly better buffering capacity, reflected as a more constant pH throughout the storage period.

Acetates↗
PubMed2001

Influence of temperature, filter wettability, and timing of filtration on the removal of WBCs from RBC concentrates.

BACKGROUND: The efficacy of the removal of WBCs from buffy coat-reduced RBC concentrates by filtration is determined by many variables. The aim of this study was to investigate the influence of the filtration temperature, the wettability of the filter material, and the timing of the filtration after collection. STUDY DESIGN AND METHODS: The investigation used commercially available filters: 3 dry "online" filters (Cellselect FR, Fresenius Hemocare; BioR-01-max, Fresenius; Leucoflex LCG1, MacoPharma) and one wet "inline" filter (Leucoflex LCR4, MacoPharma) that contained saline-adenine-glucose-mannitol additive solution for RBCs and differed from the online version only in wettability. After buffy coat removal and suspension in saline-adenine-glucose-mannitol, filtrations were performed immediately at room temperature (RT) and after 2 hours' storage of the RBC concentrates at 4 degrees C, while the Leucoflex LCR4 was also tested after 24 hours' storage of the RBC concentrates at 4 degrees C. Sets of 12 pooled experiments were performed to prevent donor-dependent differences. RESULTS: The Cellselect FR gave significantly better WBC removal from RBC concentrates at 4 degrees C than at RT, with residual WBCs of 1.44 +/- 0.58 x 10(6) and 2.78 +/- 1.23 x 10(6), respectively (p<0.001). The BioR-01-max gave no significant difference: 0.62 +/- 0.27 x 10(6) WBCs (at 4 degrees C) versus 0.61 +/- 0.25 x 10(6) WBCs (at RT). Filtration with the Leucoflex LCG1 resulted in 0.06 +/- 0.03 x 10(6) and 0.07 +/- 0.07 x 10(6) WBCs at 4 degrees C and RT, respectively, which is not a significant difference. The Leucoflex LCR4, however, gave 2.08 +/- 0.84 x 10(6) WBCs at RT, 0.52 +/- 0.44 x 10(6) WBCs at 4 degrees C after 2 hours' cooling, and 0.05 +/- 0.10 x 10(6) WBCs at 4 degrees C after 24 hours' cooling (all p<0.001). CONCLUSION: Temperature, filter wettability, and timing of filtration after collection influence the efficacy of a filter for RBC concentrates. These variables need to be established, validated, and controlled before a filter can be selected for routine use.

Blood Component Removal↗
PubMed2001

WBC-reduced platelet concentrates from pooled buffy coats in additive solution: an evaluation of in vitro and in vivo measures.

BACKGROUND: The use of a platelet additive solution (PAS-II, Baxter) may have benefits over plasma for storage of platelets. It was the aim of this study to develop a method to produce WBC-reduced platelet concentrates (PCs) in PAS-II with >240 x 10(9) platelets and <1 x 10(6) WBCs per unit, which can be stored for 5 days at pH >6.8 and that will give sufficient platelet increments after transfusion: a 1-hour CCI of >7.5 and a 20-hour CCI of >2.5. STUDY DESIGN AND METHODS: PCs were made from five pooled buffy coats and 250 g of PAS-II. After centrifugation the PCs were WBC-reduced with a filter (Autostop BC, Pall Biomedical) and stored in a 1000-mL polyolefin container. CCIs were assessed in stable hemato-oncologic patients after 5-day old PCs were transfused. RESULTS: Routinely produced PCs contained a median of 310 x 10(9) platelets (n = 5,363) with 3.5 percent containing <240 x 10(9) platelets, in a median volume of 320 mL (n = 11,834). The median number of WBCs was <0.03 x 10(6) (n = 694). The WBC count exceeded 1 x 10(6) in three PCs, but it was always <5 x 10(6), giving 99-percent confidence that more than 99.5 percent of the units will contain <1 x 10(6) WBCs. The pH remained >6.8 on Day 8, provided the concentration was below 1.1 x 10(9) platelets per mL (n = 32). After 28 transfusions in 28 patients, the 1-hour CCI was 12.6 +/- 4.3 (mean +/- SD, with 2/28 CCIs <7.5) and the 20-hour CCI was 8.9 +/- 5.6 (with 4/28 CCIs <2.5). Limitations of this study include the absence of a control group of patients receiving platelets stored in plasma and of in vivo radiolabeled survival studies, but a comparison of these data with previously published data suggested that the in vivo survival of platelets stored in PAS-II is less than that of platelets stored in plasma. CONCLUSION: The WBC-reduced PCs conformed to specifications. These WBC-reduced PCs could be stored at least 5 days with maintenance of pH, and they gave sufficient increments after transfusion to patients.

Adenine↗
PubMed2000

Leukoreduction of platelet concentrates using a 'polishing' filter.

BACKGROUND AND OBJECTIVES: Filters for removal of leukocytes from platelet concentrates (PCs) usually have a large volume to guarantee sufficient leukoreduction. In this study, a small filter, with a volume of only 8 ml and therefore minimal platelet loss, for leukoreduction of PCs was investigated. This filter has a 'limited' leukoreducing capacity, hence the filter is called a 'polishing' filter. MATERIALS AND METHODS: PCs were made from 5 pooled buffy coats in either plasma or additive solution (PAS-II). After centrifugation, the platelet-rich supernatant was expressed on an automated separator (Compomat G4) to an empty transfer bag. The content of this transfer bag was filtered into the platelet storage bag, either by expression by lowering the top press of the Compomat G4, or by gravity by hanging it on a filtration rack. RESULTS: Leukocyte counts before and after filtration revealed a mean leukoreducing capacity for the filter of 2.67 log(10) and a platelet loss of only 2% for PCs in PAS-II (n = 50), and for PCs in plasma a 3.43 log(10) leukoreduction with 3% platelet loss (n = 30). Expression of the PCs both in plasma and PAS-II through the filter using the Compomat G4 resulted in 10/10 units containing <5x10(6) leukocytes, but 1/10 PCs contained >1x10(6) leukocytes for both solutions. Filtration by gravity resultet in 40/40 units with <1x10(6) leukocytes for PCs in plasma, and 60/60 units with <1x10(6) for PCs in PAS-II. CONCLUSION: The 'polishing' filter allows reliable, standardized and automated production of PCs, both in plasma and additive solution with minimal platelet loss, and containing uniformly <1x10(6) leukocytes, provided the filtration procedure is performed by gravity.

Filtration↗
PubMed1999

Six filters for the removal of white cells from red cell concentrates, evaluated at 4 degrees C and/or at room temperature.

BACKGROUND: Six filters were tested for their ability to remove white cells from buffy coat-depleted red cell concentrates at various temperatures. STUDY DESIGN AND METHODS: Cellselect FR, BPF4, and Sepacell filters were tested at both room temperature (RT) and 4 degrees C. The Leucoflex filter was tested only at 4 degrees C, while the Cellselect Optima Plus and Imugard filters were tested only at RT. Donor-dependent differences were excluded by pooling and subsequently dividing 9 red cell concentrates; 12 sets of experiments were performed. RESULTS: With all filters, red cell concentrates containing <5 x 10(6) white cells per unit were obtained. The lowest numbers of residual white cells were achieved with the Leucoflex (at 4 degrees C, 0.15 +/- 0.11 x 10(6), the Sepacell (at 4 degrees C, 0.23 +/- 0.14 x 10(6), the Imugard (at RT, 0.24 +/- 0.14 x 10(6), and the BPF4 (at 4 degrees C, 0.25 +/- 0.24 x 10(6); differences not significant). With the Cellselect FR, filtration at 4 degrees C resulted in 0.86 +/- 0.37 x 10(6) white cells per unit, a level not significantly different from that obtained with the BPF4 and Sepacell filters at RT (1.16 +/- 0.43 x 10(6) and 0.80 +/- 0.36 x 10(6) white cells, respectively). Filtration at RT with the Cellselect FR and Cellselect Optima Plus resulted in red cell concentrates with 1.79 +/- 0.69 x 10(6) and 2.29 +/- 0.69 x 10(6) white cells, respectively (p<0.01). CONCLUSION: All filters conformed to the current standards for white cell reduction; the process was less efficient at RT than at 4 degrees C. For routine application, the composition of the red cell concentrate, the temperature, and logistic preferences should be taken into account in the final choice of filter; before implementation, the chosen filter must be validated under routine conditions.

Blood Cell Count↗
PubMed1999

Preparation of leukodepleted platelet concentrates from pooled buffy coats: prestorage filtration with Autostop BC.

BACKGROUND AND OBJECTIVES: Our requirements for leukocyte-depleted platelet concentrates (LD-PC) for an adult patient are: platelets >240x10(9), leukocytes <5x10(6), volume of 150-400 ml; and at the end of storage a pH between 6.8 and 7.4 and presence of the swirling effect. Our aim was to develop a standardized, semiautomated method for the production of LD-PC, by pooling of buffy coats (BC), and prestorage leukoreduction by filtration. MATERIALS AND METHODS: Whole blood was collected in Top and Bottom systems, and separated automatically with the Compomattrade mark G3 equipment into a red cell concentrate, a plasma and a BC. Subsequently, a pool of 5 BC was made, and 200 g plasma from one of the donors was added. Then, after soft spin centrifugation, the platelet rich plasma was leukocyte depleted by filtration using the Autostoptrade markBC filter, and stored in a 1,000 ml polyolefin platelet storage bag. RESULTS: BC (n = 60) had a volume of 51+/-2 ml (mean +/- SD) with a hematocrit of 0.44+/-0.03 l/l and contained 80+/-5% of the platelets and 74+/-12% of the leukocytes of the whole blood. Routinely prepared LD-PC (n = 15,037) contained a median of 341x10(9) platelets (range 49-599x10(9)), with only 104/15,037 (0.7%) containing fewer than 240x10(9) platelets; the median volume was 263 ml (range 134-373 ml). In 118/917 (13%) LD-PC leukocytes were observed in the Nageotte hemocytometer, but only twice exceeding 1x10(6) leukocytes per unit, and none exceeding 5x10(6) (median <0. 6x10(6); range <0.6-1.41x10(6)). Storage experiments of the LD-PC (n = 12) revealed adequate oxygenation and maintenance of pH and swirling effect up to 9 days. CONCLUSIONS: This method warrants with 99% confidence that LD-PC contain more than 240x10(9) platelets; with 97.5% confidence that 100% of the LD-PC contain <5x10(6) leukocytes, and with 95% confidence that more than 99% of the LD-PC contain fewer than 1x10(6) leukocytes; these LD-PC can be stored satisfactorily for up to 9 days.

Automation↗