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Background A new platelet (PLT) additive solution, bicarbonated Ringer's solution supplemented with acid-citrate-dextrose Formula A, termed BRS-A, as well as a new automated closed system cell processor for washing PLTs have recently been developed. This study evaluated the in vitro properties of PLTs with the automated system versus the manual method, using the BRS-A additive solution for washing and storage. Methods ABO-identical apheresis PLTs in 100% plasma were pooled and split equally for control (in 100% plasma or a manual method) and test (ACP215 automated system) units. In vitro characteristics of PLTs washed with the automated system were compared to those of PLTs in 100% plasma (Study 1) or washed with a manual method (Study 2) during the 7-day storage. Results In Study 1, hypotonic shock response, aggregation response, mitochondrial membrane potential, adenosine triphosphate, and CD42b mean fluorescence intensity were comparable in the control and test groups during the 7-day storage. CD62P expression was lower in the test group than controls on Days 3 and 7. The level of platelet-derived microparticles (PDMPs) in the test group on Days 1 and 2 were higher than those in controls. In contrast, the levels of soluble CD40 ligand (sCD40L) and regulated upon activation of normal T-cell expressed and secreted (RANTES) in the test units were lower than controls. In Study 2, no significant differences were found in all in vitro properties except for PLT count and the levels of PDMPs in the test units were higher than controls during storage. Conclusion Apheresis PLTs washed with the automated system using BRS-A additive solution maintained in vitro properties during storage. Washing methods influenced PDMP levels but not sCD40L and RANTES.

Background A new platelet (PLT) additive solution, bicarbonated Ringer's solution supplemented with acid-citrate-dextrose Formula A, termed BRS-A, as well as a new automated closed system cell processor for washing PLTs have recently been developed. This study evaluated the in vitro properties of PLTs with the automated system versus the manual method, using the BRS-A additive solution for washing and storage. Methods ABO-identical apheresis PLTs in 100% plasma were pooled and split equally for control (in 100% plasma or a manual method) and test (ACP215 automated system) units. In vitro characteristics of PLTs washed with the automated system were compared to those of PLTs in 100% plasma (Study 1) or washed with a manual method (Study 2) during the 7-day storage. Results In Study 1, hypotonic shock response, aggregation response, mitochondrial membrane potential, adenosine triphosphate, and CD42b mean fluorescence intensity were comparable in the control and test groups during the 7-day storage. CD62P expression was lower in the test group than controls on Days 3 and 7. The level of platelet-derived microparticles (PDMPs) in the test group on Days 1 and 2 were higher than those in controls. In contrast, the levels of soluble CD40 ligand (sCD40L) and regulated upon activation of normal T-cell expressed and secreted (RANTES) in the test units were lower than controls. In Study 2, no significant differences were found in all in vitro properties except for PLT count and the levels of PDMPs in the test units were higher than controls during storage. Conclusion Apheresis PLTs washed with the automated system using BRS-A additive solution maintained in vitro properties during storage. Washing methods influenced PDMP levels but not sCD40L and RANTES.

Washed platelet concentrates (WPC) have been used for patients with severe non-hemolytic febrile transfusion reaction (NHFTR) following ordinary PC transfusion. We studied three synthetic platelet storage solutions, namely Solution 1 containing saline including 0.1% citrate, Solution 2 based on acetate Ringer's solution with glucose and citrate, and Solution 3 being Seto solution designed for longer storage of PC. The pH of PC washed with Solution 1 rapidly decreased from 6.37 to 5.82 after 1 day storage, but remained at 6.8 throughout storage for 5 days with Solutions 2 and 3. On day 5, Pselectin concentrations in the supernatant of PC washed with Solution 3 were still lower than those washed with Solution 1 or Solution 2 and stored for 1 day or 3 days, respectively. The percent hypotonic shock response (%HSR) of Solution 1 was completely lost after 1 day storage, and Solution 2 reached about 20% after 3 day storage. %HSR and discoid shape were maintained at a high level, for 5 days by using Solution 3. These results suggest that Solution 3 is the most desirable solution for platelets. Owing to the rapid deterioration of platelet quality, we recommended that transfusion of WPC prepared with Solution 1 or Solution 2 be done within 6 hr or 1 day, respectively.

Two clones of the K562 human leukemic cell line were isolated according to hemoglobin (Hb) expression. One clone was expressed less than 5% (K562-L) and the other more than 90% (K562-H). The two clones did not exhibit any difference in cell growth or cell cycle. However, the Hb expression of K562-H cells was reduced by succinylacetone (S.A.). The above results suggested that the difference in the Hb production of K562-L and K562-H cells depended on the heme synthetic activity. On the other hand, glycophorin A was expressed to a greater extent on K562-L cells than on K562-H cells. These findings suggested that heme synthesis and the expression of glycophorin A on K562 cells were not always related. The CD11b and the CD61 were also expressed to a greater extent on K562-L cells than on K562-H cells, but the CD34 was not expressed on these cells.

Two subclones (K562-L and -H) were previously isolated from K562 human leukemic cells according to hemoglobin production : K562-L was expressed in less than 5% and K562-H in more than 90% of dianisidine positive cells. 12-O-Tetradecanoylphorbol-13-acetate (TPA) suppressed the expression of the erythrocytic (glycophorin A) and myelocytic (CD11b) antigens in K562-L, but increased the expression of these antigens in K562-H. TPA increased the megakaryocytic (CD61) antigens in both cells. These findings suggest that there are distinct TPA responsible factors in K562-L and -H on the expression of the erythrocytic and myelocytic antigens.