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Introduction During continuous renal replacement therapy (CRRT), preload-independent patients risk of becoming preload-dependent in case of excessive net ultrafiltration (UF NET ). We aimed to evaluate the ability of a UF NET challenge to identify de novo preload-dependence in preload-independent patients undergoing CRRT. Materials and methods We conducted a single-center, randomized, cross-over trial, enrolling adult patients with CRRT, calibrated continuous cardiac index (CCI) monitoring, and preload-independent at time of enrolment. The diagnostic test consisted of 250-ml UF NET removal over 15 (fast challenge) or 30 min (slow challenge), preceded and followed by a postural maneuver (PM) evaluating preload-dependence using CCI relative variations. Patients underwent both types of challenges, starting with either fast or slow challenges as determined by randomization, separated by a wash-out period of 24 h. We evaluated the performance of UF NET challenges to diagnose de novo preload-dependence using the area under the receiver operating curve (AUROC) of the relative change in calibrated cardiac index between before and after the challenge (∆CI UFC ), based on the result of the PM performed after the challenge (responder if positive, non-responder if negative). NCT05214729. Results We included 20 patients, comprising 36 UF NET challenges (19 fast and 17 slow challenges). In intention-to-treat (ITT), the rate of preload-dependence after the challenge was 33% (12/36, 95% confidence interval: 19% to 51%). In ITT, the AUROC of ∆CI UFC to identify de novo preload-dependence was 0.74 (95% confidence interval: 0.58–0.88), with the respective AUROCs of fast and slow challenges not reaching statistical significance. After exclusion of 5 challenges a posteriori identified as being preload-dependent before challenge start (modified intention-to-treat [mITT], N = 31), the AUROC of ∆CI UFC was 0.83 (0.66–0.99), with ∆CI UFC not significantly differing between fast and slow challenges. In mITT, CCI variation during the PM preceding the challenge predicted de novo preload-dependence with an AUROC of 0.82 (0.65–0.98), at an optimal threshold of + 5%. Conclusions A 250-ml UF NET challenge had acceptable diagnostic performance to identify preload-independent patients becoming preload-dependent during CRRT, with no detectable difference between fast and slow challenges. A CCI variation ≥ 5% during a PM in preload-independent patients may help identify those at risk of becoming preload-dependent.

Patients with decompensated heart failure and cardiorenal syndrome were randomly assigned to ultrafiltration or diuretic therapy. Ultrafiltration was inferior to diuretics with respect to the primary end point, a bivariate measure of change in creatinine and body weight. The acute cardiorenal syndrome (type 1) is defined as worsening renal function in patients with acute decompensated heart failure. 1 It occurs in 25 to 33% of patients with acute decompensated heart failure and is associated with poor outcomes. 1 , 2 Multiple processes contribute to the development of the acute cardiorenal syndrome, including extrarenal hemodynamic changes, neurohormonal activation, intrarenal microvascular and cellular dysregulation, and oxidative stress. 1 In some cases, intravenous diuretics, which are often administered in patients with acute decompensated heart failure, 3 may directly contribute to worsening renal function. 1 , 4 , 5 The use of diuretics to treat persistent congestion after the onset . . .

In asymmetrical flow field-flow fractionation (AF4), similar to other separation techniques, mass recovery and overloading require special attention in order to obtain quantitative results. We conducted a systematic study with five globular proteins of different molecular weight (36.7–669 kDa) and isoelectric point (4.0–6.5), and ultrafiltration membranes that are commonly used in aqueous AF4, regenerated cellulose (RC) and polyethersulfone (PES). Phosphate-buffered saline (PBS) with ionic strength 0.15 M and pH 7.2 was used as the carrier liquid in this study. The actual molecular weight cutoff (MWCO) was found to be higher than the nominal value and varied between membranes of different chemistry but the same nominal MWCO. Adsorption on the membrane was found to be dependent on the membrane chemistry (RC had lower adsorption compared to PES), and independent of the protein standard for the examined proteins. On the other hand, the mass overloading effects (i.e., higher retention times, peak broadening, and fronting peaks) were significantly more pronounced for γ-globulin than for the other proteins. The overloading effects could be rationalized with the increase of the local viscosity close to the membrane, depending on the properties of the proteins, and we derived theoretical equations that related the dependency of the migration velocity on the protein concentration through this non-ideal viscosity effect.

Background Carry Life UF is a novel peritoneal dialysis (PD) technology for improved fluid management using steady concentration PD (SCPD). The Carry Life UF treatment starts with a manual peritoneal fill of 1.36% glucose PD fluid, followed by a 5-hour treatment where small amounts of glucose are continuously added to maintain a stable intraperitoneal glucose concentration. A recent in-center clinical study using the Carry Life UF system demonstrated higher ultrafiltration (UF) rates, more efficient use of glucose (increased UF volume/gram of glucose absorbed), and greater sodium removal with the Carry Life UF treatments compared with a 2.27% glucose continuous ambulatory PD (CAPD) dwell. The aim of this study is to compare efficacy and safety of the Carry Life UF system with a standard CAPD prescription in the home setting. Methods A prospective, multicenter, randomized, crossover study of 19 adult subjects at up to 12 sites in Italy, Sweden and the UK will complete the investigation. End-stage kidney disease patients with a CAPD prescription of 2–4 exchanges per day, including at least one 2.27% glucose dwell, will be included. After a Carry Life UF glucose dose determination phase performed in-clinic, subjects will be randomized to start the home treatment part of the study with either the control arm (2.27% glucose CAPD dwell) or the Carry Life UF arm (11 or 15 g/h glucose dose), each for four weeks. The primary endpoint is UF volume comparing the control CAPD 2.27% glucose dwell with the Carry Life UF treatment. Secondary endpoints include adverse event rates, peritoneal sodium removal, glucose UF efficiency, and peak dialysate glucose concentration. Discussion This study will evaluate a novel PD technology in the home environment. Challenging aspects include the need to accurately measure UF volumes at home and to support subjects in using a novel technology. The study design considers important parameters for precise UF volume measurements and provides detailed weighing instructions to the study team to ensure consistency between study centers. Research nursing support will be provided for training of subjects and to support endpoint data collection in the subjects’ home. Due to the significant burden associated with the study, subjects will be offered a fair compensation, in accordance with local regulations. Trial registration ClinicalTrials.gov Identifier: NCT05874804 Registration date: 18th of April 2023.

Fluid overload is common after resuscitation in critically ill patients and is independently associated with unfavorable outcomes. Ultrafiltration (UF) during renal replacement therapy is a common strategy to reverse this condition. Nevertheless, the optimal timing, dose, and safety limits remain unclear. Observational studies suggest a U-shaped relationship between net UF rate and mortality, highlighting a narrow therapeutic window. Insufficient UF prolongs exposure to congestion, whereas excessive UF may precipitate hemodynamic instability and tissue hypoperfusion. This phenomenon, often labeled “UF intolerance”, lacks a standardized definition and is frequently attributed to intravascular volume depletion alone, overlooking broader cardiovascular and autonomic mechanisms. This perspective synthesizes the physiological effects and cardiovascular response to ultrafiltration and reframes “ultrafiltration intolerance” as a multidimensional construct determined by four compensatory axes: vascular refilling, cardiac response, venoconstriction/venous capacitance, and systemic arteriolar resistance. We delineate how renal replacement therapy-related factors interact with underlying critical illness to impair these axes and precipitate tissue hypoperfusion. Building on this framework, we (i) argue for proactive, individualized ultrafiltration prescriptions; (ii) propose dynamic predictors that emulate fluid removal to reveal physiologic reserve (iii) outline pragmatic, bedside endotypes of ultrafiltration intolerance: preload dependence, cardiac dysfunction, decreased vascular tone, autonomic dysfunction, and impaired vascular refilling. We propose a holistic framework that emphasizes prevention over rescue and guides tailored ultrafiltration prescription based on endotypes. Ultrafiltration intolerance in critically ill patients is multifactorial and not solely a problem of volume depletion. A physiology-based, preventive, and personalized ultrafiltration strategy (anchored in dynamic testing, ultrasound-based congestion profiling, and perfusion monitoring) may improve hemodynamic tolerance, decongestion efficacy, and patient-centered outcomes. Prospective studies should validate these concepts to establish evidence-based protocols for personalized ultrafiltration in critical care.

Ultrafiltration membranes are widely used in the treatment of surface water. However, membrane fouling is a core issue that needs to be addressed in its application. Magnetotactic bacteria (MTB) show early film-forming and magnetotactic behaviour in the presence of external magnetic fields. The objective of this study was to alleviate membrane fouling in ultrafiltration membranes using MTB, which can prioritise film formation and show directional movement under external magnetic fields. The concentration of Cr6+ in the water was 10 mg/L, and the dosage of MTB was 10 mg/L. Results show that the transmembrane pressure of the ultrafiltration membrane decreased by 5 kPa following the application of a magnetic field of 33.71 mT for a period of 90 min, and the membrane fouling could therefore be effectively controlled. With the addition of MTB, the average removal of Cr6+ from water by the ultrafiltration system was 20.10%, which was 14.56% higher than that of the conventional ultrafiltration system. The average removal of chromaticity was 20.13%, which was 10% higher than that achieved by the conventional ultrafiltration system. Furthermore, MTB progressively developed into the predominant flora during the operational phase, thereby enhancing the efficiency of the ultrafiltration system.

In patients treated with haemodiafiltration, high convection volumes are considered beneficial. However it leads to pressure instability and membrane fouling. We aimed to identify critical ultrafiltration fluxes based on different approaches including the maximal global ultrafiltration coefficient ( G K D−UF  max), and to test the influence of ultrafiltration on system stability and membrane fouling. Experiments of cross-flow filtration of a protein-containing fluid (cow milk) were performed. The ultrafiltration rate (Q UF ) was sequentially modified using a peristaltic pump and transmembrane pressure (TMP) was recorded. G K D−UF and TMP stability over time were assessed. Q UF critical values were estimated from the G K D−UF , critical flux, irreversible fouling and sustainable flux approaches. Membrane fouling was observed by microscopy. Proteins from the feed, ultrafiltrate and retained on membrane were assessed by protein assays and SDS-PAGE. The G K D−UF  max approach identified Q UF critical values close to the irreversible fouling and sustainable flux. When Q UF exceeded critical values, major increase in TMP over time was observed and more clogged dialyzer fibres were detected. Utilizing Q UF below the G K D−UF max critical value lead to stable TMP over time and fewer clogged fibres therefore G K D−UF  max is helpful to identify the critical ultrafiltration rate and can be used to optimize ultrafiltration flow that prevent membrane fouling.

Colloid-enhanced ultrafiltration (CEUF), i.e., micellar-enhanced ultrafiltration (MEUF) and polymer-enhanced ultrafiltration (PEUF), was investigated to remove sulfate ions from aqueous solution in batch experiments, using cetyltrimethylammonium (CTAB) and poly(diallydimethylammonium chloride) (PDADMAC) as colloids, respectively. Ultrafiltration performance was evaluated under different initial concentrations of sulfate (0–20 mM) and CTAB/PDADMAC (0–100 mM). The highest retention rate (> 99%) was found in dilute sulfate solutions. At high sulfate concentrations (e.g., 10 mM), a dosage of 50 mM CTAB or PDADMAC can retain approximately 90% of sulfate ions. Though concentration polarization behavior was observed, membrane characterization indicated that the fouling was reversible and membranes can be reused. Furthermore, adsorption equilibrium and kinetics studies show that Freundlich isotherm and pseudo-second-order kinetics can describe the sulfate-colloid interaction, indicating that the surface of absorbents are heterogeneous and the rate-controlling step is chemisorption. Both MEUF and PEUF show potential as effective separation techniques in removing sulfate from aqueous solutions. Under the same conditions examined, PEUF shows advantages over MEUF in its higher retention at lower polymer-to-sulfate ratios, cleaner effluent, and higher adsorption capacity, but compromises on severer flux decline and a tendency of membrane fouling. To overcome this disadvantage, membranes with higher molecular weight cut-off can be used.

The plant virus cowpea mosaic virus (CPMV) is being developed as a drug candidate for intratumoral immunotherapy for solid tumours. Data from preclinical studies in mice and rats as well as clinical studies in canine cancer patients demonstrate potent efficacy and an excellent safety profile. Toward Investigational New Drug (IND)‐enabling studies, a scalable and Good Manufacturing Practice (GMP)‐compatible manufacturing process must be developed. Therefore, here, we focused on the downstream process and developed a scalable purification process. We systematically screened the following processes: acidic extraction conditions making use of the virion pH stability, ultrafiltration making use of the nanoparticle character and the virion size, and finally ion exchange chromatography based on the virion's surface charge. The three processes were then combined into a 7‐step protocol, providing efficiency compared to the contemporary laboratory procedures involving various centrifugation steps (and a total of 15 steps to yield pure CPMV). Furthermore, we streamlined the removal of endotoxins by combining detergent‐based endotoxin removal with ion exchange chromatography. The new ultrafiltration‐based process reduced the number of unit operations by more than half and the processing time from ~20 to ~7 h compared to centrifugation‐based purification of CPMV. Importantly, toxic organic solvents, ultracentrifugation and isopycnic ultracentrifugation which are difficult to scale were omitted. We used a battery of characterisation methods to validate CPMV's structural integrity and biological activity.

Chronic kidney disease affects 10–15% of the global population, with hemodialysis causing significant thirst and xerostomia due to fluid restrictions. These symptoms impair quality of life and treatment adherence. While ultrafiltration (UF) and sodium profiling have been studied separately, their combined effect remains understudied, particularly in Middle Eastern populations. We conducted a randomized crossover trial with 20 ESRD patients comparing: (1) ascending/descending UF with linear sodium reduction (150→138 mmol/L) versus (2) conventional HD with constant UF/sodium (140 mmol/L). Participants completed 16 sessions per protocol with washout periods. Outcomes were measured using validated Thirst Questionnaire (5-item) and Xerostomia Inventory (11-item), both showing excellent reliability (Cronbach’s α > 0.7/>0.8). The intervention group showed significant improvements versus conventional HD: 44% reduction in thirst scores (36.5 vs. 64.5, p  < 0.001). 22% lower xerostomia (19.0 vs. 24.4, p  = 0.002). 73% fewer hypotension episodes (15% vs. 55%, p  < 0.05). These benefits are mechanistically linked to improved hemodynamic stability achieved through synergistic sodium and ultrafiltration profiling. This approach, which maintains plasma osmolality and intravascular volume, offers a practical, cost-neutral solution for symptom management. This approach significantly ameliorates patient-reported thirst and xerostomia and reduces intradialytic hypotension, offering a practical, cost-neutral strategy to enhance treatment tolerability. This approach should be adopted in routine practice, particularly for the growing ESRD population. Future studies should explore personalized strategies and long-term effects. Trial registration: This study was registered in the Iranian Registry of Clinical Trials (no. IRCT20180429039463N5) on 07/01/2023. https//irct.behdasht.gov.ir/trial/67,695.