[Appreciative calamity investigation].

Calamity investigations often lead to recommendations that are difficult to implement and that are of little relevance, because the analysis is carried out according to a cause and effect system. The complexity of care provision requires a different method that respects the complexity of day-to-day care and is able to assess it correctly. Research according to the Safety-II philosophy clearly shows the variable interactions and dependencies present in daily work.

Preparation of leukodepleted platelet concentrates from pooled buffy coats: prestorage filtration with Autostop BC.

Background And Objectives: Our requirements for leukocyte-depleted platelet concentrates (LD-PC) for an adult patient are: platelets >240x10(9), leukocytes <5x10(6), volume of 150-400 ml; and at the end of storage a pH between 6.8 and 7.4 and presence of the swirling effect.

Leukocyte filtration mechanisms. Factors influencing the removal of infectious agents from red cell concentrates.

The purpose of the present overview was to determine the factors influencing the removal of infectious agents from red cell concentrates by filtration. In general, the efficacy of the filtration method depends on the physical as well as the functional properties of blood cells. These properties are highly influenced by the changes exerted on the blood cells during blood collection, processing and storage and the filtration method itself.

In vitro evaluation of platelet concentrates, prepared from pooled buffy coats, stored for 8 days after filtration.

Background: Posttransfusion complications can be prevented by pretransfusion removal of donor white cells from platelet concentrate. The filtration used for this removal seems to have little effect on platelet function and activation, but more information is needed on its effect on function during subsequent long-term storage of concentrate.

Study Design And Methods: The effect of prestorage filtration of buffy coat-prepared platelet concentrates (PCs) on platelet function, metabolism, and activation was investigated.

Effect of filtration on subsequently stored platelet concentrates.

The effect of filtration on the quality of platelet concentrates (PC) during storage was investigated. Two leukocyte depletion filters (Pall PL50HF and Sepacell PL-10A) were applied to filter PC made from a pool of 4 buffy coats. For each experiment 3 PC were pooled and divided into 3 identical PC to eliminate differences between the PC.

Poly(ethyleneimine) modified filters for the removal of leukocytes from blood.

Polyurethane membrane filters and filters coated with poly(ethyleneimine) were used to investigate the influence of leukocyte adhesion during filtration. Treatment of the filters with an aqueous solution of 1% (w/v) poly(ethyleneimine) (PEI) led to the introduction of amine groups at the filter surfaces, as was confirmed by X-ray photoelectron spectroscopy. The modification procedure did not significantly change the porous structure in the filters, as was demonstrated by SEM and porometry.

Mechanisms of white cell reduction in red cell concentrates by filtration: the effect of the cellular composition of the red cell concentrates.

The effect of platelets on the removal of white cells (WBCs) from 16 to 24-hour-old red cell (RBC) concentrates by filtration was studied. RBC concentrates with various concentrations of platelets and WBCs were filtered on a cellulose acetate column filter and on three polyester flatbed filters. The microscopic study revealed that lymphocytes and most monocytes were captured in the smaller pores of the fiber network, irrespective of the brand of filter, the type of filter material, or the prefiltration platelet amount in the RBC concentrates.

Electronmicroscopic examination of white cell reduction by four white cell-reduction filters.

The mechanisms of white cell (WBC) reduction in 16-hour-old CPDA-1 red cell (RBC) concentrates by filtration on a column filter and on three different flatbed filters were studied by electron microscopy, with special emphasis on cell-to-cell interaction, cell damage, and interaction of blood cells with the material. Generally, lymphocytes were removed by mechanical sieving and monocytes by adherence and mechanical sieving. Granulocyte depletion occurred by mechanical sieving, direct adhesion to the fibers, and indirect adhesion to activated and spread platelets.

Comparison of five different filters for the removal of leukocytes from red cell concentrates.

The leukocyte depletion capacity and performance of 5 filters designed for filtration of red cell concentrates (RCC) were compared by counting leukocytes, measuring red cell volumes and by histological examination of the filters after use. To eliminate interdonor differences, 5 buffy-coat-poor RCC were pooled (in each of 10 experiments) and subsequently split up into the original bags. The RCC were passed over the Cellselect filter, a column filled with cellulose acetate, and over flat-bed polyester filters: the Cellselect Optima, the Pall RC 50, the Leukostop and the Sepacell R-500.

Asymmetric membrane filters for the removal of leukocytes from blood.

As part of a study on the mechanisms of leukocyte filtration, the influence of pore size distribution on filter efficiency was investigated. Conventional leukocyte filters are not suitable for model studies, as these filters are composed of tightly packed synthetic fibers, with a poorly defined porous structure. Therefore, open cellular polyurethane membranes with pore size distributions varying from approximately 15 to 65 microns were prepared.

Histologic and immunohistochemical studies on the preparation of white cell-poor red cell concentrates: the filtration process using three different polyester filters.

Three third-generation white cell (WBC)-depletion filters based on polyester layers with decreasing pore size were investigated. In the coarse layers, unaggregated granulocytes, monocytes, and platelets and aggregates of these cells were captured in close contact with the fibers. This indicates that the depletion of granulocytes, monocytes, and platelets in the coarse layers of the filters is due in part to activation and adhesion with the formation of cell clusters on the fibers.

Histological and immunohistochemical studies on the preparation of leukocyte-poor red cell concentrates by filtration: the filtration process on cellulose acetate fibers.

A histological and immunohistochemical investigation of slices from the Cellselect leukocyte filter showed that the capture of lymphocytes within these filters depended on trapping of the cells in the cellulose acetate fiber network more than on adherence. Probably, additional mechanisms played a role in granulocyte removal. Microaggregates of granulocytes and platelets were found at the top of the Cellselect leukocyte filter.

Binding of human IgA1 and IgA1 fragments to jacalin.

Interaction of jacalin, an N-terminal galactose specific lectin, with human IgA1 and IgA1 fragments was investigated. IgA1 and all galactose containing fragments bound to jacalin-Sepharose, including Fab fragments containing only the galNac linked to serine-224 and Fc fragments containing four gal-galNac sequences. These data indicate that both the galNac and gal-galNac sequences can interact with jacalin.

Effect of serum albumin on the recovery of human IgA1 from immobilized jacalin.

Published methods for affinity purification of human IgA1 on immobilized jacalin are based on binding through galNac residues in the IgA1 hinge region. The present study shows that in addition to this galNac-dependent binding an 'alternative' binding mechanism, involving protein-protein interactions, is operative. Moreover, human (HSA) and bovine (BSA) serum albumins were also observed to interact with jacalin through the 'alternative' mechanism, though much more weakly than IgA1.