FLC removal with adsorbent resins represents an effective therapeutic strategy that does not require replacement with albumin .

Chronic renal failure patients accumulate in the blood molecules that are normally excreted into the urine. p-Cresol Sulphate (pCS), the most representative retained toxin, shows a high level of toxicity. Therefore, its quantification could represent a prediction factor to determine the risk of endothelial dysfunction and cardiovascular complication and response to the haemodialysis treatment. The aim of this study was to evaluate the suitability of the multiple reaction monitoring (MRM) technique in order to improve the sensibility, the selectivity and the timing of pCS detection in a small amount of plasma. Deproteinized plasma of uremic patients was concentrated and dissolved in liquid chromatography (LC) mobile phase solution. pCS was quantified by LC coupled to tandem mass spectrometry (LC-MS/MS) on a triple-quadrupole mass spectrometer. Selective and sensitive detection of pCS was achieved by selecting the specific parent ion and monitoring two specific fragment ions. The MRM assay was carried out using the following transitions: m/z 187 → 80.00 and m/z 187 → 107.00. A good linearity was observed for each calibration curve. The intra-day and inter-day results showed a good precision and repeatability. The percentage recoveries indicate an optimal selectivity of the analytical method. The MRM assay to quantify pCS in a small amount of human plasma is rapid, highly sensitive, selective and with a good repeatability.

The uremic syndrome is attributed to the progressive retention of a large number of toxins, which under normal conditions are excreted by the healthy kidneys. Standard dialytic membranes do not purify middle-high molecular weight toxins. Haemodiafiltration with endogenous reinfusion coupled with a highly permeable membrane could break the limit of the 'albumin wall' improving the dialytic depuration without loss of important nutrients. The aim of this study was to evaluate the performance of a new polysulfone membrane, Synclear 0.2, to remove uremic molecules. Surface Enhanced Laser Desorption Ionization-Time of Flight was employed to evaluate the proteomic profile of ultrafiltrate and Electrospray Ionization-Quadruple-ToF coupled with on-chip elution was used for proteins identification. A high and specific permeability for middle-high molecular weight molecules was revealed by mass spectrometry for the investigated membrane. The identified proteins are mostly uremic toxins: their relative abundance, estimated in the ultrafiltrate by exponentially modified protein abundance index, showed a high purification efficiency of the new membrane when compared with conventional ones. In conclusion, Synclear 0.2, used as convective membrane in hemodiafiltration with endogenous reinfusion treatment, permits to break the 'albumin wall', clearing middle-high molecular weight uremic toxins, improving the dialytic treatment purification efficiency.

We have devised a supramolecular edifice involving His-tagged protein A and antibodies to yield surface immobilized, uniformly oriented, IgG-type, antibody layers with Fab fragments exposed off an electrode surface. We demonstrate here that we can affect the conformation of IgGs, likely pushing/pulling electrostatically Fab fragments towards/from the electrode surface. A potential difference between electrode and solution acts on IgGs’ charged aminoacids modulating the accessibility of the specific recognition regions of Fab fragments by antigens in solution. Consequently, antibody-antigen affinity is affected by the sign of the applied potential: a positive potential enables an effective capture of antigens; a negative one pulls the fragments towards the electrode, where steric hindrance caused by neighboring molecules largely hampers the capture of antigens. Different experimental techniques (electrochemical quartz crystal microbalance, electrochemical impedance spectroscopy, fluorescence confocal microscopy and electrochemical atomic force spectroscopy) were used to evaluate binding kinetics, surface coverage, effect of the applied electric field on IgGs, and role of charged residues on the phenomenon described. These findings expand the concept of electrical control of biological reactions and can be used to gate electrically specific recognition reactions with impact in biosensors, bioactuators, smart biodevices, nanomedicine, and fundamental studies related to chemical reaction kinetics.