Simple and efficient ultrafiltration method for purification of rotavirus VP6 oligomeric proteins.

Bacterial endotoxins, DNA, live viruses, and viral proteins derived from bacterial and baculovirus (BV) expression vectors employed in recombinant protein production contaminate the final product. Density gradient centrifugation is commonly used to partially purify oligomeric proteins, but impurities from the expression system still remain. We describe a simple and rapid ultrafiltration method for final purification of rotavirus VP6 oligomeric nanotubes and nanospheres. Contamination originating from the BV vector used in VP6 production was undetectable. The method is highly efficient, fast and inexpensive and can be used for a small-scale laboratory purification of VP6 protein to replace technically demanding multi-step chromatographic procedures.

Triple bottom line assessment of raw water treatment: methodology and application to a case study in the municipality of Oppegård in south-eastern Norway.

There could be several options a water treatment plant (WTP) can select from, if an improvement in treated water quality (WQ) is desired. This paper outlines a methodology to test a variety of approaches to accomplish pre-set goals as regards WQ, while adopting a triple bottom line approach. This approach, in a nutshell, takes into consideration economic, environmental and social aspects in decision-making. The methodology has been applied to the Stangasen WTP in the town of Oppegård in south-eastern Norway. Among the seven alternative approaches compared were the use, as coagulant, of five different dosages of granulated aluminium sulphate, liquid aluminium sulphate (48%) and liquid ferric chloride (40%). Using the set of weighting factors obtained from experts, it was determined that increasing the dosage of granulated aluminium sulphate by 20% over the current one would be the most sustainable option from a triple bottom line point of view.

Extracorporeal versus peritoneal ultrafiltration in diuretic-resistant congestive heart failure--a review.

Diuretic-resistant congestive heart failure in the form of type 2 cardiorenal syndrome is a problem of growing significance in everyday clinical practice because of high morbidity and mortality. There has been scant progress in the treatment of overhydration, the main cause of symptoms in this group of patients. The aim of our review is to present recent advances in the ultrafiltration therapy of congestive heart failure, with special attention to the new dedicated device for extracorporeal isolated ultrafiltration, as well as modifications of peritoneal dialysis in the form of peritoneal ultrafiltration with icodextrin solution and incremental peritoneal dialysis. Technical and clinical features, costs and potential risks of available devices for isolated ultrafiltration are presented. This method should be reserved for patients with true diuretic resistance as part of a more complex strategy aiming at the adequate control of fluid retention. Peritoneal ultrafiltration is presented as a viable alternative to extracorporeal ultrafiltration because of medical and psychosocial benefits of home-based therapy, lower costs and more effective daily ultrafiltration. In conclusion, large, properly randomized and controlled clinical trials with long-term follow-up will be essential in assessing the logistics and cost-effectiveness of both methods. Most importantly, however, they should be able to evaluate the impact of both methods on preservation of renal function and delaying the progression of heart failure by interrupting the vicious circle of cardiorenal syndrome. Our review is supplemented with the case report of the use of peritoneal ultrafiltration with a single 12-hour nighttime icodextrin exchange as a life-saving procedure in a patient with congestive heart failure resistant to pharmacological treatment.

The path to wearable ultrafiltration and dialysis devices.

Wearable blood processing devices offer an attractive solution to problems inherent in clinic-based, intermittent end-stage renal disease therapies. What is involved in transitioning even a part of the current clinic-based population to ambulatory therapy has not been clearly enumerated. This paper addresses what a first-generation wearable device might accomplish, how issues of safety will need to be addressed, and what will make the device attractive to, and manageable by, the patient. Medical, technological, and economic issues are identified.

The substitution of sand filtration by immersed-UF for surface water treatment: pilot-scale studies.

The newly issued National Drinking Water Standard required that turbidity should be lower than 1 NTU, and the substitution of sand filtration by immersed ultrafiltration (immersed-UF) is feasible to achieve the standard. This study aimed to optimise the operational processes (i.e. aeration, backwashing) through pilot scale studies, to control membrane fouling while treating the sedimentation effluent. Results indicated that the immersed-UF was promising to treat the sedimentation effluent. The turbidity was below 0.10 NTU, bacteria and E. coli were not detected in the permeate water. The intermittent filtration with aeration is beneficial to inhibit membrane fouling. The critical aeration intensity is observed to be 60.0 m(3) m(-2) h(-1). At this aeration intensity, the decline rate of permeate flux in one period of backwashing was 1.94% and 7.03% for intermittent filtration and sustained filtration respectively. The different membrane backwashing methods (i.e. aeration 1.5 min, synchronous aeration and water backwashing 2 min, water backwashing 1.5 min; synchronous aeration and water backwashing 3 min, water backwashing 2 min; aeration 3 min, single water backwashing 2 min; synchronous aeration and water backwashing 5 min; single water backwashing 5 min) on the recovery of permeate flux were compared, indicating that the synchronous aeration and water backwashing exhibited best potential for permeate flux recovery. The optimal intensity of water backwashing is shown to be 90.0 L m(-2) h(-1). When the actual water intensity was below or exceeded the value, the recovery rate of permeate flux would be reduced. Additionally, the average operating cost for the immersed UF membrane, including the power, the chemical cleaning reagents, and membrane modules replacement, was about 0.31 RMB/m(3).

Reclamation of the wastewater from an industrial park using hollow-fibre and spiral-wound membranes: 50 m3 d(-1) pilot testing and cost evaluation.

The feasibility of reclaiming effluent from industrial park wastewater treatment plants through a membrane process was evaluated in three phases. In phase 1 we selected nine wastewater treatment plants (WWTPs), each with a design capacity exceeding 10,000 m3 d(-1), and analyzed the corresponding effluent composition. 'Potential recycling percentage', R, ranged from 50% to 80% for the industrial park WWTPs, indicating a high feasibility for the reuse of effluent. In phase 2, a 50 m3 d(-1) pilot plant was installed in one of the selected WWTPs and underwent testing for one year. The quality of the reclaimed water was suitable for general-purpose industrial use. In the two ultrafiltration (UF) modules tested, the hydrophilic polyethersulfone hollow-fibre module was more tolerant to variable properties, and had higher recycling percentages than those of backwashable hydrophobic polyvinylidene difluoride spiral-wound module. Using the spiral-wound UF module helped reduce the cost for producing 1 m3 of reclaimed water (US$0.80) compared with a hollow-fibre module (US$0.88). In phase 3, we evaluated the negative effects of refluxing the reverse osmosis retentate, containing high total dissolved solids and non-biodegradable organics, with the biological treatment unit of the upstream WWTP. Biological compactibility tests showed that the refluxed retentate ratio should be reduced to maintain the conductivity of mixed liquor in the aeration tank at less than 110% of the original value.

Ultrafiltration versus diuretics for the treatment of fluid overload in patients with heart failure: a hospital cost analysis.

Background: Heart failure (HF) is a common, serious disease in the US and Europe. Patients with HF often require treatment for fluid overload, resulting in costly inpatient visits; however, limited evidence exists on the costs of alternative treatments. This study performed a cost-analysis of ultrafiltration (UF) vs diuretic therapy (DIUR-T) for patients with HF from the hospital perspective. Methods: The model used clinical data from the literature and hospital data from the Healthcare Cost and Utilization Project to follow a decision-analytic framework reflecting treatment decisions, probabilistic outcomes, and associated costs for treating patients with HF and hypervolemia with veno-venous UF or intravenous DIUR-T. A 90-day timeframe was considered to account for hospital readmissions beyond 30 days. Sensitivity and scenario analyses were performed to gauge the robustness of the results. Results: Although initial hospitalization costs were higher, fluid removal by UF reduced hospital readmission days, leading to cost savings of $3,975 (14.4%) at the 90-day follow-up (UF costs, $23,633; DIUR-T costs, $27,608). Conclusions: UF is a viable alternative to DIUR-T when treating fluid overload in HF patients because it reduces hospital readmission rates and durations, which substantially lowers costs over a 90-day period compared to DIUR-T.

Ultrafiltration Therapy for Heart Failure: Balancing Likely Benefits against Possible Risks.

Heart failure remains a major public health concern because of its high prevalence, morbidity, mortality, and financial burden. The poor clinical outcomes associated with acute decompensated heart failure, suboptimal efficacy and safety profile of conventional treatment regimens, and unsatisfactory experiences with the newer classes of pharmacologic therapy underlie the interest in the use of extracorporeal isolated ultrafiltration in this setting. In this article, selected mechanistic aspects of ultrafiltration therapy are briefly reviewed followed by a critical overview of the largest trials in this field. I will discuss the clinical relevance of renal dysfunction and decongestion as two commonly used end points of safety and efficacy in the ultrafiltration trials, with emphasis on the emerging pertinent notions that could challenge our conventional thinking. Finally, a number of practical recommendations (e.g., customization of ultrafiltration rates) are provided for ultrafiltration therapy in the setting of acute decompensated heart failure. Because of a paucity of evidence, universally accepted consensus guidelines cannot yet be generated. As such, when considering ultrafiltration therapy for acute decompensated heart failure, the likely benefits should be carefully balanced against the potential risks for an individual patient. A conceivable implication of the ultrafiltration trials is that collaborative heart failure programs benefiting from nephrology expertise and resources could improve the outcomes and reduce the cost.

Enzyme recovery and recycling following hydrolysis of ammonia fiber explosion-treated corn stover.

Both cellulase and cellobiase can be effectively recovered from hydrolyzed biomass using an ultrafiltration recovery method. Recovery of cellulase ranged from 60 to 66.6% and for cellobiase from 76.4 to 88%. Economic analysis shows that cost savings gained by enzyme recycling are sensitive to enzyme pricing and loading. At the demonstrated recovery of 60% and current loading of 15 Filter paper units of cellulase/g of glucan, enzyme recycling is expected to generate a cost savings of approx 15%. If recovery efficiency can be improved to 70%, the savings will increase to >25%, and at 90% recovery the savings will be 50%.

Membrane bio-reactor for textile wastewater treatment plant upgrading.

Textile industries carry out several fiber treatments using variable quantities of water, from five to forty times the fiber weight, and consequently generate large volumes of wastewater to be disposed of. Membrane Bio-reactors (MBRs) combine membrane technology with biological reactors for the treatment of wastewater: micro or ultrafiltration membranes are used for solid-liquid separation replacing the secondary settling of the traditional activated sludge system. This paper deals with the possibility of realizing a new section of one existing WWTP (activated sludge + clariflocculation + ozonation) for the treatment of treating textile wastewater to be recycled, equipped with an MBR (76 l/s as design capacity) and running in parallel with the existing one. During a 4-month experimental period, a pilot-scale MBR proved to be very effective for wastewater reclamation. On average, removal efficiency of the pilot plant (93% for COD, and over 99% for total suspended solids) was higher than the WWTP ones. Color was removed as in the WWTP. Anionic surfactants removal of pilot plant was lower than that of the WWTP (90.5 and 93.2% respectively), while the BiAS removal was higher in the pilot plant (98.2 vs. 97.1). At the end cost analysis of the proposed upgrade is reported.

Evaluation of Membrane Ultrafiltration and Residual Chlorination as a Decentralized Water Treatment Strategy for Ten Rural Healthcare Facilities in Rwanda.

There is a critical need for safe water in healthcare facilities (HCF) in low-income countries. HCF rely on water supplies that may require additional on-site treatment, and need sustainable technologies that can deliver sufficient quantities of water. Water treatment systems (WTS) that utilize ultrafiltration membranes for water treatment can be a useful technology in low-income countries, but studies have not systematically examined the feasibility of this technology in low-income settings. We monitored 22 months of operation of 10 WTS, including pre-filtration, membrane ultrafiltration, and chlorine residual disinfection that were donated to and operated by rural HCF in Rwanda. The systems were fully operational for 74% of the observation period. The most frequent reasons for interruption were water shortage (8%) and failure of the chlorination mechanism (7%). When systems were operational, 98% of water samples collected from the HCF taps met World Health Organization (WHO) guidelines for microbiological water quality. Water quality deteriorated during treatment interruptions and when water was stored in containers. Sustained performance of the systems depended primarily on organizational factors: the ability of the HCF technician to perform routine servicing and repairs, and environmental factors: water and power availability and procurement of materials, including chlorine and replacement parts in Rwanda.

Multiple ligand detection and affinity measurement by ultrafiltration and mass spectrometry analysis applied to fragment mixture screening.

Binding affinity of a small molecule drug candidate to a therapeutically relevant biomolecular target is regarded the first determinant of the candidate's efficacy. Although the ultrafiltration-LC/MS (UF-LC/MS) assay enables efficient ligand discovery for a specific target from a mixed pool of compounds, most previous analysis allowed for relative affinity ranking of different ligands. Moreover, the reliability of affinity measurement for multiple ligands with UF-LC/MS has hardly been strictly evaluated. In this study, we examined the accuracy of K(d) determination through UF-LC/MS by comparison with classical ITC measurement. A single-point K(d) calculation method was found to be suitable for affinity measurement of multiple ligands bound to the same target when binding competition is minimized. A second workflow based on analysis of the unbound fraction of compounds was then developed, which simplified sample preparation as well as warranted reliable ligand discovery. The new workflow implemented in a fragment mixture screen afforded rapid and sensitive detection of low-affinity ligands selectively bound to the RNA polymerase NS5B of hepatitis C virus. More importantly, ligand identification and affinity measurement for mixture-based fragment screens by UF-LC/MS were in good accordance with single ligand evaluation by conventional SPR analysis. This new approach is expected to become a valuable addition to the arsenal of high-throughput screening techniques for fragment-based drug discovery.

Dialysis modalities in the intensive care unit.

Acute renal failure in the ICU is a clinically diverse entity. Consequently, the indications for initiation of dialysis therapy are varied. In general, the indications are solute control, volume control, or both. A variety of dialysis modalities are available; however, there is no consensus as to the optimal modality for any particular group of patients. A careful understanding of the particular benefits, limitations, and potential complications of each modality coupled with a thorough assessment of the individual patient's need formulate the basis for dialysis modality selection. In certain circumstances, the more conventional intermittent therapies are sufficient, whereas in other settings, CRRT techniques are advantageous. The impact of modality selection on outcome remains an area of significant controversy. Future studies in which more uniformity within specific subgroups of patients with ARF is sought may shed light on the optimal modality for a particular patient group. Newer therapies aimed at more optimal and more specific blood purification may prove promising in the management of complex critically ill patients with ARF and other comorbid conditions.

Performance of the biosorptive activated sludge (BAS) as pre-treatment to UF for decentralized wastewater reuse.

A biosorptive activated sludge (BAS) was operated at lab-scale with diluted and concentrated municipal wastewater to study the efficiency of removal of organics (particulate and soluble COD) and recovery of nutrients (TKN, ammonia, phosphorus). The system performed significantly better with concentrated wastewater, where COD removal efficiency was 80% at organic loading rates between 10 and 20kg m(-3)d(-1). Supplementation of ferrous iron at 20mg L(-1), significantly improved both the removal of particulate, soluble COD and phosphorus. The effluent from the BAS was further treated using an ultrafiltration process with backwashing. The average permeate flux (at constant TMP=0.3bar) increased from 23 to 28 and 34L m(-2)h(-1) when raw sewage, BAS without iron, and iron respectively were tested. The proposed technology is compact, efficient and suitable for decentralized water reuse, while the capital and operational expenses were calculated as 0.64 and 0.43€ m(-3), respectively.

Cardiorenal syndrome: ultrafiltration therapy for heart failure--trials and tribulations.

Heart failure remains the leading cause of hospitalization in older patients and is considered a growing public health problem with a significant financial burden on the health care system. The suboptimal efficacy and safety profile of diuretic-based therapeutic regimens coupled with unsatisfactory results of the studies on novel pharmacologic agents have positioned ultrafiltration on the forefront as an appealing therapeutic option for patients with acute decompensated heart failure (ADHF). In recent years, substantial interest in the use of ultrafiltration has been generated due to the advent of dedicated portable devices and promising results of trials focusing both on mechanistic and clinical aspects of this therapeutic modality. This article briefly reviews the proposed benefits of ultrafiltration therapy in the setting of ADHF and summarizes the major findings of the currently available studies in this field. The results of more recent trials on cardiorenal syndrome that present a counterpoint to previous observations and highlight certain limitations of ultrafiltration therapy are then discussed, followed by identification of major challenges and unanswered questions that could potentially hinder its more widespread use. Future studies are warranted to shed light on less well characterized aspects of ultrafiltration therapy and to further define its role in ADHF and cardiorenal syndrome.

Styrene process condensate treatment with a combination process of UF and NF for reuse.

Aiming at reusing the SPC to save water resource and heat energy, a combination treatment process of UF/NF was applied to remove inorganic irons, suspended particles and little amount of organic contaminants in this article. To achieve the indexes of CODM≤5.00 mg L(-1), oil≤2.00 mg L(-1), conductivity≤10.00 µs cm(-1), pH of 6.0-8.0, the NF membrane process was adopted. It was necessary to employ a pretreatment process to reduce NF membrane fouling. Hence UF membrane as an efficient pretreatment unit was proposed to remove the inorganic particles, such as iron oxide catalyst, to meet the influent demands of NF. The effluent of UF, which was less than 0.02 mg L(-1) of total iron, went into a security filter and then was pumped into the NF process unit. High removal efficiencies of CODM, oil and conductivity were achieved by using NF process. The ABS grafting copolymerization experiment showed that the effluent of the combination process met the criteria of ABS production process, meanwhile the process could alleviate the environment pollution. It was shown that this combination process concept was feasible and successful in treating the SPC.

Phosphorus recovery from sewage sludge with a hybrid process of low pressure wet oxidation and nanofiltration.

Phosphorus recovery from sewage sludge will become increasingly important within the next decades due to depletion of mineral phosphorus resources. In this work a new process concept was investigated, which aims at realising phosphorus recovery in a synergistic way with the overall sewage sludge treatment scheme. This process combines a low pressure wet oxidation for sewage sludge decomposition as well as phosphorus dissolution and a nanofiltration process to separate phosphorus from heavy metals and obtain a clean diluted phosphoric acid, from which phosphorus can be recovered as clean fertiliser. It was shown that this process concept is feasible for sewage sludge for wastewater treatment plants that apply enhanced biological removal or precipitation with alumina salts for phosphorus removal. The critical parameter for phosphorus dissolution in the low pressure wet oxidation process is the iron concentration, while in the nanofiltration multi-valent cations play a predominant role. In total, a phosphorus recovery of 54% was obtained for an exemplary wastewater treatment plant. Costs of the entire process are in the same range as conventional sewage sludge disposal, with the benefit being phosphorus recovery and reduced emission of greenhouse gases due to avoidance of sludge incineration.

Integrated downstream processing of lactoperoxidase from milk whey involving aqueous two-phase extraction and ultrasound-assisted ultrafiltration.

The present work involves the adoption of an integrated approach for the purification of lactoperoxidase from milk whey by coupling aqueous two-phase extraction (ATPE) with ultrasound-assisted ultrafiltration. The effect of system parameters of ATPE such as type of phase system, polyethylene glycol (PEG) molecular mass, system pH, tie line length and phase volume ratio was evaluated so as to obtain differential partitioning of contaminant proteins and lactoperoxidase in top and bottom phases, respectively. PEG 6000-potassium phosphate system was found to be suitable for the maximum activity recovery of lactoperoxidase 150.70% leading to 2.31-fold purity. Further, concentration and purification of enzyme was attempted using ultrafiltration. The activity recovery and purification factor achieved after ultrafiltration were 149.85% and 3.53-fold, respectively. To optimise productivity and cost-effectiveness of integrated process, influence of ultrasound for the enhancement of permeate flux during ultrafiltration was also investigated. Intermittent use of ultrasound along with stirring (2 min acoustic and 2 min stirring) resulted in increased permeate flux from 0.94 to 2.18 l/m(2) h in comparison to the ultrafiltration without ultrasound. The use of ultrasound during ultrafiltration resulted in increase in flux, but there was no significant change in activity recovery and purification factor. The integrated approach involving ATPE and ultrafiltration may prove to be a feasible method for the downstream processing of lactoperoxidase from milk whey.

Ultrafiltration for acute decompensated heart failure: cost, reimbursement, and financial impact.

In addition to the proposed pathophysiologic mechanisms whereby ultrafiltration (UF) can be advantageous over diuretics in the treatment of heart failure, there can also be financial and resource-utilization reasons for pursuing this extracorporeal strategy. In those cases in which the clinical outcomes would be equivalent, however, the decision whether to pursue UF will depend greatly on the anticipated hospitalization length of stay (LOS), the patient population's pay or mix, the needs and costs for high-acuity (eg, intensive care unit) care, and widely varying expenses for the equipment and disposable supplies. From a fiscal perspective, the financial viability of UF programs revolves around how improvements in LOS, resource utilization, and readmissions relate to the typical diagnosis-driven (eg, diagnosis-related group) reimbursement. We analyzed the impact of these various factors so as to better understand how the intensity (and expense) of pharmaceutical and extracorporeal therapies impacts a single admission, as well as to serve as the basis for developing strategies for optimizing long-term care.

Beneficios del descanso peritoneal / Benefits of peritoneal rest

Introducción: Valorar si el descanso peritoneal, de al menos un día semanal, ha supuesto mejoras en la rehabilitación de los pacientes y el impacto clínico que puede suponer. Nos planteamos además cuantificar el beneficio económico. Material y Método: Se realizó un estudio longitudinal, retrospectivo, descriptivo. De los pacientes atendidos en nuestra unidad desde el 1 de enero de 2014 al 31 de diciembre de 2014, se estudiaron los pacientes que cumplieran todo el año de seguimiento y que no procedieran de otras técnicas de depuración como la hemodiálisis o trasplante renal. La muestra de estudio estuvo compuesta por 40 pacientes, de los que 21 tuvieron prescrito al menos 1 día semanal de descanso peritoneal y 19 pacientes sin descanso. Se recogieron las siguientes variables al inicio del periodo de estudio y a los 12 meses: Variables demográficas, variables relacionadas con el estado de volumen, datos clínicos relacionados con la técnica, se pasó una encuesta de satisfacción a todos los pacientes estudiados, y se recogieron los importes del coste mensual de cada tipo de tratamiento. Resultados: Las diferencias iniciales entre los grupos, eran esperables ya que son los valores en los cuales se ha basado la prescripción del día de descanso. La exposición a la glucosa, al comienzo y al final fue menor en el grupo con descanso. Al año, no se encontró diferencias en los parámetros estudiados. Una encuesta de satisfacción nos reveló a que dedican los pacientes el día de descanso y los que no lo tienen a que lo dedicarían. Conclusiones: El descanso peritoneal no ha supuesto una peor evolución de los parámetros clínicos estudiados al año de seguimiento, cumpliendo las recomendaciones de adecuación de diálisis de las guías clínicas. La exposición a la glucosa, aun sin llegar a ser significativa por la duración del estudio, ha sido menor en el grupo con descanso. El día de descanso ha facilitado a los pacientes mejorar su rehabilitación social principalmente. Los días de descanso han supuesto un ahorro de al menos 13,33% en la factura mensual (AU)

Introduction: To assess whether the peritoneal rest at least one day a week has led to improvements in the rehabilitation of patients, and the clinical impact that can be achieved. We also propose to quantify the economic benefit. Material and methods: A longitudinal, retrospective, descriptive study was conducted. Of those patients seen in our unit from 1 January 2014 to 31 December 2014, patients who fulfilled all the monitoring year and that at the same time they were not subjected to other purification techniques such as dialysis or transplantation kidney were studied. The study sample was composed of 40 patients, of whom 21 had prescribed at least 1 weekly day of peritoneal rest, and 19 patients without rest. The following variables at baseline and 12 months of the study period were recorded: Demographic variables, variables related to volume status, clinical data related to the technique and data related to a satisfaction survey, as well as the amounts of the monthly cost of each type of treatment. Resultados: The initial differences between the groups were expected since they are the values on which is based the prescription of the rest day. Exposure to glucose at the beginning and the end was lower in the group with rest. At one year, no differences in the studied parameters were found. A satisfaction survey revealed to us the activity that patients spend the rest day, as well as the activity that would perform those who not rest. Conclusiones: The peritoneal rest has not meant a worse outcome of the clinical parameters studied at one year, fulfilling the recommendations of dialysis adequacy of the guidelines. Although not statistically significant for the duration of the study, exposure to glucose was lower in the group with rest. The rest day has mainly provided to patients to improve their social rehabilitation. Rest days have generated savings on the monthly bill of 13.33% (AU)