Preparation Of Platelet Concentrates Research Articles

Recovery and survival in vivo of platelet concentrates prepared with prostaglandin E1.

In follow-up to previous studies showing that stimulators of adenylate cyclase inhibit the activation of platelets in platelet concentrates (PC), the posttransfusion recovery and survival of autologous platelets prepared and stored after the addition of prostaglandin E1 (PGE1) to platelet-rich plasma at a concentration of 1.3 X 10(-8) M were investigated. Six normal subjects were studied on the two occasions, using PC stored with and without PGE1 and radiolabeling with 51Cr. The mean recovery of platelets prepared with PGE1 (35.2 +/- 8.1%) was significantly lower (p less than 0.013) than that of routinely prepared platelet concentrates (46.3 +/- 9.4%). The mean life-spans of platelets prepared with and without PGE1 were 7.1 +/- 0.4 and 6.2 +/- 1.0 days, respectively (p = NS). Despite its ability to inhibit the activation of platelets during concentration and storage, prostaglandin E1 appears to reduce posttransfusion recovery of platelets significantly in this experimental model and cannot be recommended at this time as an adjunct for PC preparation.

Analysis of platelet factor 3 in platelet concentrates stored for transfusion.

The amount of platelet factor 3 (PF3) activity expressed in stored platelet concentrates (PC) was measured in conjunction with extracellular LDH levels. Standard manual techniques for preparation of PC resulted in PF3 and LDH levels remarkably higher than those observed in PC prepared by apheresis or special manual plateletpheresis. During storage of PC, PF3 activity rose 2- to 10-fold, while LDH levels rose less than 2-fold over starting values. Loss of LDH and appearance of PF3 expressed as a percent of total per platelet were significantly correlated only in standard, manual PC. Approximately half of the PF3 activity observed in any type of PC remained in the supernatant plasma after centrifugation. Upon gel filtration, the supernatant PF3 activity eluted in a high molecular weight peak containing phosphate and light-scattering material. Our findings indicate that platelets in standard, citrated PC express PF3 in amounts that approach that of frozen-thawed (lysed) platelets; however, the manner in which the PF3 activity appears suggests that stored platelets undergo a combination of activation and damage processes.

In vitro effect on stored red blood cells and platelets after a 15-hour delayed refrigeration of whole blood prior to component preparation in CPD-AD.

We extended the time of keeping whole blood at 20-24 degrees C to 15 h (overnight) after phlebotomy for preparing platelet concentrates. We have evaluated the in vitro characteristics of platelets and blood cells prepared from whole blood drawn into CPD-AD, an anticoagulant containing 0.4 mM adenine and 1.5 times more dextrose than CPD. We studied in vitro red cell and platelet function of blood cooled either within 4 h after collection or after a 15-hour delay. In vitro platelet function measured as hypotonic shock reaction, aggregation response to ADP and collagen and 14C-serotonin uptake were not significantly different after preparation and after a 5-day storage period. Units held at room temperature for 15 h after blood collection exhibited a level of 2,3-DPG that was 45% of that exhibited by red cells held for 15 h at 1-6 degrees C. All other in vitro parameters of red cell concentrates measured during 35 days of storage were not significantly different. Based on these in vitro data blood drawn into CPD-AD might be kept up to 15 h at room temperature prior to refrigeration in order to prepare platelet concentrates.

The effect of temperature and mode of agitation on the resuspension of platelets during preparation of platelet concentrates

A problem arose in a blood bank in which about 10 percent of platelet concentrates (PC) observed at day 1 had a large number of macroscopic aggregates. The aggregates were clumps of platelets that did not go into suspension during preparation of PC. These units were set aside for observation. A maximum of 25 percent were stored on a circular rotator; the remainder were stored on either an elliptical rotator or horizontal shaker. By the end of storage, 6 percent of the units still had a large number of clumps. This percentage was reduced to 2.4 percent, when all clumped units were stored on a circular rotator. The number of clumped units observed at day 1 and at the end of storage were reduced dramatically when the temperature of the laboratory (18-19 degrees C), centrifuge (20 degrees C) and storage environmental chamber (22 degrees C) were increased to 24 degrees C. The units with clumps at day 5 were reduced from 225 (out of 8316) to 25 (out of 7137).

Rapid Preparation of Fresh Platelet Concentrates from CPD-Blood by (Mild) Acidification

Two methods of preparation of platelet concentrates (PC) derived from citrate-phosphate-dextrose (CPD) whole blood have been compared: (1) resuspension after having left the PC undisturbed at room temperature for 1 h (according to Mourad), and (2) immediate resuspension of the PC after the centrifugation of a platelet-rich plasma which has been acidified beforehand by the addition of ACD. In vitro platelet yield in acidified (CPD/ACD-)PC was at least equal to and, in cases with a particularly strong postcentrifugal tendency for clumping of platelets, clearly better (p<0.05) than in the ‘Mourad platelets’. The results show that it is possible to produce PC from fresh CPD whole blood without delay. This may be helpful in clinical situations where freshly prepared PC should be available immediately. A special double bag (Fenwal DFX 733) containing CPD-A in the primary bag and 10 ml of ACD in the satellite bag, allows preparation of PC under these conditions in a closed system.

Simple method of improving the quality of platelet concentrates and the importance of production control.

Some technical improvements of the method to prepare platelet concentrates (PC) have been developed. The contamination of the PC with red blood cells (RBC) and white blood cells (WBC) is thereby kept at a low level. A majority of routinely prepared PC did not show any visible RBC contamination which means that they contained less than 0.4 X 10(9) RBC per PC unit. None of the tested examples contained more than 1 X 10(9) RBC per PC unit. The WBC contamination was less than 0.1 X 10(9) cells per PC unit in 75 per cent of tested examples and did not exceed 0.6 X 10(9) cells per PC unit. Routine platelet counting by thrombocounter applied on samples from all PRPs was found to be a reasonably simple way to make routine PC quality control. By sufficient supervision of the details of the procedure the main yield can be maintained at about 100 X 10(9) cells per unit. By follow-up of the weekly yield any deterioration of production efficiency can easily be detected.