In comparison to progenitor platelets, microparticles are deficient in GpIb, GpIb-derived carbohydrates, glycerophospholipids, glycosphingolipids, and ceramides.

Activated blood platelets shed microparticles with procoagulant activity that probably participate in normal hemostasis. We have isolated spontaneously formed microparticles from human blood and analysed them for ultrastructure, antigenic profile, and biochemical composition. In transmission electron microscopy microparticles appeared as regular vesicles with a mean diameter of 300 nm (50-600 nm). In flow cytometry almost all microparticles reacted with fluorescein isothiocyanate (FITC) labeled antibody to platelet glycoprotein complex IIb-IIIa (GpIIb-IIIa) and with FITC-annexin V but only 40-50% of microparticles reacted with FITC-antibody to platelet glycoprotein Ib (GpIb). The latter result was confirmed by double labeling of microparticles with FITC-antibody to GpIIb-IIIa and phycoerythrin (PE) labeled antibody to GpIb. Large microparticles reacted better with anti-GpIb than the small ones. A decreased level of GpIb was also demonstrated by SDS/polyacrylamide gel electrophoresis of microparticles. Compositional studies indicated, that in terms of cholesterol and protein contents, microparticles resembled platelets rather than platelet membranes as previously thought. They are, however, deficient in certain components. Thus, in comparison to platelets, microparticles had reduced contents of sialic acid (by 56.4%), galactosamine (by 48.2%), glucosamine (by 22.4%), galactose by (11.8%) and fucose (by 21.6%). Mannose content was increased by 11.8%. Total phospholipids in microplatelets were lower by 17.8%. Glycerophospholipids only were affected with phosphatidylserine being decreased as much as by 43.2%. Neutral glycosphingolipids, gangliosides and ceramides in microparticles were reduced by half.

[Comparison of platelet and leukocyte content in platelet concentrates obtained from CS-3000 and third generation (CS-3000 plus and Cobe-Spectra) cell separators]. / Porównanie zawartosci plytek krwi i leukocytów w koncentratach krwinek plytkowych, otrzymanych przy uzyciu separatora CS-3000 oraz separatorów III generacji (CS-3000 plus i Cobe-Spectra).

Platelet concentrates (PCs) obtained using old generation of cell separators contain high number of leukocytes. White cell (WBC) contamination and platelet (Plts) number in PCs obtained from separator II-nd generation CS-3000 and separators III-rd generations CS-3000 plus and Cobe-Spectra have been determined. PCs from new separators contain the same Plts number as PCs from CS-3000. The average leukocyte count in PCs obtained from CS-3000 was 171.26 x 10(6), whereas WBC number in PCs from CS-3000 plus and Cobe-Spectra were 2.87 and 2.54 x 10(6) respectively. In about 85% of PCs obtained from III-rd generation cell separators the leukocyte count did not exceed 5 x 10(6). This count is considered sufficient to prevent alloimmunization of HLA antigens. The determination of WBC count in every PCs allows to select PCs with fewer than 5 x 10(6) leukocytes and to transfuse them without the necessity of using expensive filters for leukocyte removing.

[Comparison of platelet concentrates obtained using blood cell separators with continuous flow: CS-3000 and Cobe-Spectra]. / Porównanie jakosci koncentratów plytkowych otrzymanych przy uzyciu separatorów z przeplywem ciaglym: CS-3000 i Cobe-Spectra.

During a platelet apheresis procedure on CS-3000 the platelet concentrate (Pc) is centrifugated for about 1.5 h. In the Cobe system Pc is gradually collected in a container located outside the machine. Influence of both techniques on platelet viability and function was examined in vitro. MPV, hypotonic stress response (HSR), aggregation using ADP, activity and percent leakage of lactic dehydrogenase (LDH) were similar in both groups. ATP contents in platelets (Plts) obtained on CS-3000 reached 5.18 +/- 0.75 mumol/10(11) Plts and was significantly lower than in Plts collected on Cobe-Spectra: 7.26 +/- 1.00 mumol/10(11) Plts. The functions of Plts obtained on both blood cell separators, immediately after collection, appeared to be correct. ATP level reduction in Plts from CS-3000 suggests that prolonged centrifugation leads to Plts activation which can affect cells during storage.

[Evaluation of platelet quality obtained using conventional methods or from buffy-coat and stored at room temperature]. / Ocena jakosci plytek krwi uzyskanych metoda konwencjonalna oraz z kozuszka leukocytarno-plytkowego przechowywanych w temperaturze pokojowej.

A comparison has been made between platelet concentrates (Pcs) obtained from buffy coat (Bc) and from platelet rich plasma. The method of preparation proves to have an platelet properties in vitro. Both types of Pcs were investigated immediately after isolation as well as during the 5 day period of storage. It has been confirmed that due to the new technique the number of white cells in Pcs could be reduced 25 fold (to 2.79 +/- 1.68 x 10(6)/unit). It has also been showed that traditional way of obtaining Pcs provokes a greater platelet activation than the new technique. The storage conditions of Pcs obtained from Bc must however be practically defined because when CLX containers are used, afer 5 days an excessive pH increase (to 7.59), aggregation decline and HSR weakening are observed.

[Platelet transfusion from HPA typed donors in alloimmune thrombocytopenia of newborns and fetuses]. / Przetaczanie plytek krwi od dawców z oznaczonymi antygenami HPA w alloimmunologicznej maloplytkowosci noworodków lub plodów.

The registry of donors typed for HPA-1 and HPA-3 antigens is presented. Three cases of fetal/neonatal alloimmune thrombocytopenia (F/NAIT) transfused with typed platelets either from mother or from registered donors are discussed. All children were transfused just after delivery, one in addition in utero: they survived not having any haemorrhagic complications in central nervous system inspite of such complications in previous born siblings. In the paper the general rules of platelet transfusions in F/NAIT are discussed.

[Sialic acid level in blood platelets after cryopreservation with DMSO]. / Poziom kwasów sialowych krwinek plytkowych przechowywanych po kriopreparatyce z DMSO.

Plasma platelet concentrates of man were subjected to preparatory procedures with dimethylsulphoxide (DMSO) as a cryoprotective agent. It was demonstrated that DMSO acting directly on the platelets in concentrations used in routine preparation had no effect decreasing the level of sialic acids in the platelets. Cryopreservation of platelets in presence of DMSO caused the loss of 30% of the sialic acids from the platelets. Further storage at room temperature of defrosted platelet concentrates caused no further decrease of sialic acid level in these cells. ++Cryopreservation decreased also the aggregation ability of the platelets after induction with ADP but simultaneous action of ADP and succinate increased the aggregation of ++cryopreserved platelets.