Platelet concentrates from buffy coats: improved conditions for preparation and evaluation in routine clinical use

Since 1990, platelet concentrates prepared by soft centrifugation of buffy-coat pools diluted with a glucose-free, commercially available crystalloid solution (BC-PC) are the first choice product for all platelet recipients in our institution. Numerous in vitro and in vivo observations from our own and other laboratories indicate that BC-PC compare favorably to PC prepared from platelet-rich plasma (PRP). In the present in vitro study we evaluated traditional and bottom-and-top bags and modified centrifugation conditions with the aim of increasing in vitro platelet yield in BC-PC. This was 14-18% higher compared with our previous protocol when prolonged centrifugation and bottom-and-top bags were used. In addition, we evaluated post-transfusion platelet count increments in 42 unselected adult hematological patients routinely transfused with 703 1-5 day-old BC-PC pools. Transfusion data were managed with PLATELET, an MS-DOS compatible program which includes automated calculation of transfusion efficacy and periodic patient reports. Mean pre-, 1 h and 24 h post-transfusion platelet counts were 16, 38 and 28x10 9/L, respectively. Mean 1 h and 24 h post-transfusion platelet count increments, expressed as percentage of expected, were 40 and 24%, respectively. These data were similar to those obtained previously in 189 unselected hematological patients given 2432 PRP-PC transfusions (mean 1 h post-transfusion increment 46% of expected). The present in vitro study confirms that similar platelet yields can be obtained with the BC and PRP methods. In vivo findings show that also in routine conditions post-transfusion increments of PRP-PC and BC-PC are similar.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hormonal changes during surgical stress. Comparison of isoflurane anesthesia, neuroleptanalgesia, propofol]

Our purpose is to verify if different techniques of general anaesthesia can modify the patient's hormonal response to surgical stress. For this extent 35 patients, undergoing Cottle's septoplasty, were randomly divided into three groups, treated using different anaesthesiological techniques (forane, NLA and propofol). No variation was noted between the three groups regarding cortisol increments, while the patients, in whom forane was used for anaesthesia maintenance, manifested less significant variations in prolactin levels. This may be indicative of good forane protection for surgical stress.

Role of acetate during platelet storage in a synthetic medium

It has previously been shown that buffy coat platelet concentrates (BC-PCs) stored in a medium made up of approximately 70 percent platelet storage medium (Plasma-Lyte A, PL) and 30 percent plasma (BC-PC-P) are effective in vivo after 9 to 12 days of storage. In addition to sodium, potassium, magnesium, and chloride, PL contains 27 mM (27 mmol/L) sodium acetate and 23 mM (23 mmol/L) sodium gluconate. This study investigated the effect of acetate and gluconate on platelet metabolism. Identical BC-PCs were stored at 22 +/- 2 degrees C in PL (BC-PC-P); PL with gluconate but without acetate, termed PL-A (BC-PC-A); or PL with acetate but without gluconate, termed PL-G (BC-PC-G). On Day 1 of storage, no significant differences were seen between the three groups of BC-PCs. In both BC-PC-P and BC-PC-G, pH and bicarbonate were stable at 7.0 +/- 0.03 and 8.4 +/- 0.9 mEq per L throughout 10 days of storage, whereas in BC-PC-A, they fell to 6.7 +/- 0.05 and 5.5 +/- 0.8 mEq per L on Day 5 (p less than 0.01 vs. Day 1) and to 6.1 +/- 0.1 and 1.2 +/- 0.4 mEq per L, respectively, on Day 10. The buffering capacities of 70 percent PL, PL-A, or PL-G and 30 percent plasma were similar in a platelet-free setting when incremental additions of lactic acid were made. The role of acetate was further studied by adding 14C- or 3H-labeled acetate to BC-PC-P.(ABSTRACT TRUNCATED AT 250 WORDS)

Platelet quality after 15-day storage of platelet concentrates prepared from buffy coats and stored in a glucose-free crystalloid medium

It has been reported previously that platelet concentrates (PCs) prepared from buffy coat pools diluted in a simple, glucose-free medium (BC-PCs) are effective in thrombocytopenic patients after 4 to 12 days of storage. Such preparations produce platelet increments similar to those of traditional PCs prepared from platelet-rich plasma (PRP-PCs) stored for 1 to 3 days. The purpose of this study was to obtain a series of in vitro measurements during storage to allow a more detailed characterization of BC-PCs and a more detailed comparison of BC-PCs with PRP-PCs. At the beginning of storage, the level of (alpha granule membrane protein-140 (GMP-140), a marker of platelet activation, was significantly higher on PRP-PC platelets, and BC-PCs were superior in measurements reflecting platelet function, such as osmotic reversal, ATP release, and aggregation with collagen. Compared to PRP-PCs, BC-PCs were superior in the percentage of discs, total ATP, and glycoprotein lb expression by Day 7. This superiority became more striking on Day 11. Overall, 15-day-old BC-PCs compared favorably to 7-day old PRP-PCs: BC-PCs were superior in ATP release and aggregation with collagen, but they were not significantly different for all other measurements reflecting platelet quality and function. Thus, the quality of platelets in BC-PCs was superior on Day 1, and this superiority progressed as storage continued. In addition, the metabolism of BC-PCs was favorable.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of platelet activation and membrane glycoprotein Ib and IIb-IIIa expression after filtration through three different leukocyte removal filters

We evaluated three filters used for leukocyte removal from platelet concentrates: Imugard IG 500, Pall PL100 and Sepacell PL-10A. Filter performance, platelet activation and expression of membrane glycoproteins Ib and IIb-IIIa were evaluated. Imugard, Pall and Sepacell showed median postfiltration in vitro platelet recoveries of 88, 84 and 80%, and total residual leukocyte counts of 16.1, 7.5 and 0.6 x 10(6)/pool of 8 platelet concentrates, respectively. Mean platelet volume was reduced after filtration with all filters. Postfiltration values of glycoproteins Ib and IIb-IIIa, and of activation markers GMP 140 and gp 53 were not significantly different from prefiltration values. Filtration through Imugard, Pall and Sepacell did not induce significant platelet activation or modifications of platelet membrane glycoproteins Ib and IIb-IIIa.

Removal of white cells from red cells by transfusion through a new filter

The effectiveness of a new filter (RC100) for the preparation of white cell-depleted red cells (RBCs) at the bedside was evaluated in vitro and in vivo using three RBC products: standard RBC concentrate (CPDA units), RBCs suspended in saline-adenine-glucose-mannitol additive solution after the removal of plasma (SAGM units), and RBCs suspended in SAGM after the removal of plasma and buffy coat (SAGM-BC units). Median RBC recovery was at least 92 percent when 2 units were administered through one filter; median values for residual white cells and platelets were less than or equal to 20 x 10(6) and less than or equal to 2.5 x 10(9) per 2 units, respectively. The in vivo study was carried out in 80 multiply transfused patients with thalassemia, 35 of whom had experienced frequent nonhemolytic transfusion reactions when given standard or buffy coat-free RBCs. During the 6-month study, each patient was given two transfusions of each type of RBC product One febrile nonhemolytic transfusion reaction occurred in each of two patients receiving SAGM-BC units, but in no other case. If the flow rate is not reduced, the median transfusion time is 35 minutes per CPDA unit and 15 minutes per SAGM and SAGM-BC unit. It is concluded that the transfusion of RBCs through the RC100 is a simple and effective procedure to administer white cell-depleted RBCs prepared at the bedside.

Evaluation of platelet concentrates prepared from buffy coats and stored in a glucose-free crystalloid medium

Comparison was made between platelet concentrates prepared from pools of buffy coats removed from standard blood donations and stored in a glucose-free, commercially available crystalloid solution (BC-PCs) and standard platelet concentrates prepared from platelet-rich plasma (PRP-PCs). Platelet yield in BC-PCs and PRP-PCs was 59 and 75 percent of donated platelets, respectively. The number of total white cells in 1 BC-PC unit, prepared from a pool of 7 buffy coats, was 21 x 10(6), i.e., 50 times lower than that of 7 units of PRP-PCs. The in vitro values of adequate platelet quality were maintained for 10 days in BC-PCs stored in 1000-mL polyolefin bags. Prolonged bleeding times were reduced or corrected in three of three thrombocytopenic leukemic patients evaluated before and after transfusion of stored BC-PCs. Pretransfusion and 1- and 24-hour posttransfusion median platelet counts in 57 leukemic recipients during 4 months of routine transfusion of BC-PCs (n = 93) were 14, 35, and 27 x 10(9) per L, while those of PRP-PCs (n = 246) were 13, 37, and 31 x 10(9) per L, respectively. No reactions to BC-PCs were reported, but a 1.3 percent rate of reaction to PRP-PC transfusions was reported. This study indicates that BC-PCs are a good alternative to PRP-PCs for platelet support of thrombocytopenic patients.

Leukocyte depletion of red cell units at the bedside by transfusion through a new filter

Standard packed red cell (PRC) units can be depleted of leukocytes and platelets if they are transfused through a blood administration set in which the usual 170-mu filter has been replaced by a leukocyte removal filter (Sepacell R-500). During a 6-month period, 1550 PRC units were transfused through this filter in 611 transfusions to 80 multitransfused patients with thalassemia who had had a patient reaction rate (PRR) of 63 percent and a transfusion reaction rate (TRR) of 13 percent when given standard PRC or buffy-coat-depleted PRC. When given filtered PRC, PRR and TRR became 3.7 percent and 0.5 percent, respectively. The effectiveness of the filter was also evaluated in vitro. By filtering 2 standard PRC units through the same filter, median values (and ranges) for red cell recovery and for residual leukocytes and platelets were 87 percent (83-92), 6.1 X 10(6) (0-100), and 2.7 X 10(9) (0.6-9.7), respectively. Although refinements are needed to improve standardization of the filter and to increase red cell recovery (which is low when 1 unit is filtered through one filter) and blood administration rate, the ability to provide leukocyte-free red cells prepared at the bedside for virtually all recipients appears to be a realistic goal.

Prolidase deficiency in two siblings with chronic leg ulcerations. Clinical, biochemical, and morphologic aspects

Prolidase deficiency occurred in two sisters suffering from recurrent leg ulcers that appeared in early childhood. The patients presented the typical clinical symptoms of the disease, including characteristic facies, dermatologic manifestations of the lower extremities, splenomegaly, and hematologic anomalies. Large amounts of iminodipeptides were excreted into the urine, and prolidase activity in their erythrocytes was virtually absent. Changes associated with a connective-tissue disorder were demonstrated by light and electron microscopic studies of the patients' apparently normal skin. Collagen fibers were smaller than in controls and were irregularly packed; the fibrils had normal aspect but were significantly smaller than in one age-matched control. Elastin fibers appeared altered both in size and structure.

Preparation of leukocyte-free platelets for transfusion by filtration through cotton wool

Filtration through Imugard filters of random platelet concentrates or platelets obtained by plateletpheresis allow the preparation of leukocyte-free platelets for transfusion. The procedure is simple and determines only a small platelet loss (less than 10%). Filtered platelets seem to function normally in vivo. The use of leukocyte-free red cell and platelet transfusions for the support of patients suffering from leukemia or aplastic anemia could prevent major complications, such as refractoriness to platelet transfusion and to bone marrow transplantation.