Notice of RetractionDynamics of Protein Permeability of Filter Membranes during Artificial Kidney Therapy

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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In hemofiltration, performance of blood filters can be evaluated by the analysis of sieving coefficients and clearances. Mainly for higher molecular weight uremic toxins (middle molecules) a decrease of dialyzer clearance may be expected depending on the duration of the extracorporeal renal replacement therapy. This study was designed to validate protein permeability of different blood filters at different times of treatment. Methods: Three hemodialysis filters (dialyzers) with different membranes (FX-60^® polysulfone, Fresenius Medical Care), (Diacap HI PS 15^® polysulfone, BBraun) and (BK-1.6P^® polymethlmethacrylate, Toray Industries) were examined during the first hour of a hemofiltration treatment. Filtrate samples were collected every 15 min applying different blood flow rates (125, 250, 300 ml/min). The ultrafiltration rate (UFR) was kept at 1000 ml/h. Protein permeability of the membranes was evaluated by measurement of concentration of total protein, P2 microglobulin (β₂M) and Sodium dodecyl sulfate-Polyacrylamide gelelectrophoresis (SDS-PAGE) patterns in the filtrate. Additionally, blood reduction ratios of β₂M from the beginning to the end of hemofiltration were calculated. Results: Mean total protein concentration in filtrate is 0.09 g/1 in FX-60^®, 0.08 g/1 in HI PS 15^® and 1.0 g/1 in BK-1.6P^®. With progression of time, total protein concentration in the - iltrate of FX-60^® and HI PS 15^® is decreasing whereas in BK-1.6P® total protein concentration is increasing. From the beginning to the end of hemofiltration, the sieving coefficients (SC) of β2M increase from 0.733 to 0.825 for FX-60^® and from 0.217 to 0.370 for HI PS 15®. In BK-1.6P® sieving coefficients are always <; 0.01. In contrary, blood β2M reduction- ratio is lowest in FX-60^® (4.7%), compared with HI PS 15^® (14.7%) and highest in BK-1.6P^® (16.7%). Conclusion: Protein permeability of membranes is dynamically changing during therapy, depending on time and flow dynamics. In protein absorbing membranes, such as BK-1.6P^® even high blood β₂M reduction ratios can be achieved although sieving coefficients are nearly zero. It is concluded that when measuring in-vivo performance data of blood filters not only membrane polymers and flow rates but also the sampling time after initiation of treatment should be defined.