Biomedical subjects

M Müller-Steinhardt

Publications and source records attributed to M Müller-Steinhardt.

22 records · Page 2Linked to original sources

PubMed1995

Cytokines in platelet concentrates prepared from pooled buffy coats.

Platelet concentrates (PC) prepared from pooled buffy coat (BC-PC) contain a variable number of leukocytes from different donors. We questioned whether storage of BC-PC can lead to a lymphocyte activation in the sense of a mixed lymphocyte reaction. BC-PC were prepared from four ABO-identical buffy coats and we undertook leukocyte analyses and measurement of different cytokines on days 1, 3 and 5 of PC storage (n = 72). Cytokine content was also determined in freshly prepared plasma (n = 48) and PC prepared by thrombapheresis (SD-PC) (n = 12). As control, we studied lymphoproliferation of pooled peripheral blood mononuclear cells from four individuals in 10 mixed lymphocyte cultures (MLCs) under optimal conditions. In the BC-PC, whole blood count and lymphocyte analysis showed a mean leukocyte contamination of 64 +/- 28 x 10(6) per unit with a proportion of lymphocytes of 66.7 +/- 13%. In the MLC, levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were increased on day 3 and 5 of storage (p < 0.001). In a proportion of BC-PC, tumor necrosis factor-alpha (72.2%) and IL-2 (43.1%) were detectable immediately after preparation, whereas IFN-gamma (4.2%), interleukin-1 beta (4.2%) and interleukin-8 (11.1%) were only found in some BC-PC. In all cases, initial values of cytokines did not increase during storage. Cytokine measurement in FFP and SD-PC showed similar results. The study demonstrates that cytokines are detectable in a variety of blood products immediately after preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗

PubMed1994

[Lymphocyte interactions in platelet concentrates from buffy coats. Determination of proliferating cells using Ki-67 antibodies].

The preparation of platelet concentrates (PC) from pooled buffy coats has raised concern as to whether activation of lymphocytes may take place during the period of storage. Lymphocytes and HLA-DR-positive cells are of particular relevance, as they may induce a mixed lymphocyte reaction (MLR). Therefore we investigated the degree of leukocyte contamination and determined the quantity of proliferating leukocytes using the monoclonal antibody KI-67. The content of total leukocytes was (0.07 +/- 0.05) x 10(9). Immunostaining of KI-67-positive cells proved that, directly after preparation, only single leukocytes were activated. On days 1, 3 and 5 after preparation the results were identical. Isolated cells were found to be KI-67-positive but there was no significant increase in proliferating cells as would have been expected in an MLR. We conclude that there is no allogenic activation of lymphocytes taking place in these PC during storage. Therefore transfusion of activated lymphocytes seems to be extremely unlikely.

Antibodies↗

PubMed1992

[Differentiation of leukocytes in thrombocyte concentrates by APAAP staining].

The preparation of platelet concentrates (PC) from pooled buffy coats has raised concern as to whether activation of lymphocytes might take place during the period of storage. Therefore it appears to be essential to investigate the degree of leukocyte contamination and identify the subtypes of these cells. Especially lymphocytes are of relevance as they may induce either a mixed lymphocyte reaction (MLR), the production of cytokines or a graft-versus-host reaction. As the number of leukocytes is very low we adopted the alkaline phosphatase-antialkaline phosphatase (APAAP) technique to determine the composition of leukocytes. We used mouse monoclonal antibodies to specifically stain T lymphocytes, B lymphocytes, monocytes, HLA-DR-positive cells and NK cells. All subtypes could easily be identified and their relative amounts were determined. In samples from 15 PCs the percentages of T lymphocytes, B lymphocytes, monocytes, NK cells and HLA-DR-positive cells was 40.3, 6.4, 18.9, 7.2 and 17.1% of total leukocytes, respectively. The standard deviation ranged between 2 and 5%. We highly recommend this technique, which is a very sensitive method to determine leukocyte contamination in PC.

B-Lymphocytes↗

PubMedDate not supplied

Impact of various red cell concentrate preparation methods on the efficiency of prestorage white cell filtration and on red cells during storage for 42 days.

BACKGROUND: White cell (WBC) reduction prior to storage of red cell (RBC) concentrates may reduce the incidence of HLA alloimmunization and may improve the quality of stored RBCs. STUDY DESIGN AND METHODS: An integrated WBC-reduction filter system was tested after various RBC preparation procedures (from whole blood), and the influence of filtration on RBCs during storage for 42 days was investigated. Four additive system RBC preparation protocols were used. Units prepared from conventional triple blood bags were held for 4 to 6 hours at 22 degrees C, and then the RBCs were separated via a hard spin and filtration, performed immediately (Group 1) or after 18 hours' storage at 4 degrees C (Group 2). Units prepared from a top-and-bottom collection system were held at 22 degrees C for 4 to 6 or 22 to 24 hours; the centrifuged RBCs were filtered immediately after preparation (Groups 3 and 4, respectively, by holding time). WBC reduction and filtration time were analyzed. The impact of WBC filtration on pH, hemolysis rate, hemoglobin content, ATP, potassium glucose, and lactate was investigated weekly during storage for 42 days. RESULTS: Filtration reduced the mean WBC count by 3 to 4 log10, to 0.19 +/- 0.25 x 10(6), regardless of the RBC preparation method. Mean filtration times differed significantly between the groups and were longest for Group 1. Besides hemolysis and pH values, which were greater in all filtered units, no major differences were found in filtered and unfiltered RBCs during the storage interval. CONCLUSION: The efficiency of prestorage WBC filtration of RBCs was unaffected by the preparation procedure. However, the filtration time for RBCs freshly prepared in the conventional triple blood bag system without buffy-coat depletion was unacceptable. No major metabolic differences between filtered and unfiltered RBCs during 42 days of storage were found.

Blood Preservation↗