No Improvement of Hepatitis B Vaccination Response in Patients Dialysed with a Polymethylmethacrylate Membrane Compared to High-Flux Polysulfone: Results of the HEPADIAL Study.

BACKGROUND: An altered immune response and decreased vaccine response are observed in patients with chronic renal failure. A preliminary study of 15 non-immunised patients, despite appropriate previous hepatitis B vaccination, showed a 60% seroconversion rate after 3 months of dialysis with a polymethylmethacrylate (PMMA) membrane. This response was associated with circulating soluble CD40 (CD40s) decrease, a natural inhibitor of the humoral immune response. The aim of the study is to confirm these results in a randomised study. METHODS: We conducted a multicentre randomised intention-to-treat superiority clinical trial comparing polysulfone and a PMMA membrane in 2 parallel patient groups. The primary end point was the vaccine response rate, as defined by an anti-HBs antibodies titre of >10 IU/L, 1 month after the last vaccination with a double dose of Engerix B20®, performed at weeks 12, 16, 20, and 36. RESULTS: Twenty-five patients were randomised and included in an intention-to-treat analysis. They were dialysed on polysulfone (n = 11) or PMMA (n = 14) for 40 weeks. Fifty percent of the PMMA patients versus 54.5% of the polysulfone patients achieved seroconversion (p = 1.00). The median anti-HBs antibody titre in responders at week 40 was 496 (92-750) versus 395 (43-572) UI/mL for PMMA and polysulfone, respectively (p = 0.46). The median CD40s titre at week 12 was 306 (193-448) versus 491 (281-515) pg/mL (p = 0.21). The CD40s median variation between week 0 and week 12 was 5 (-105 to 90) versus 64 (-63 to 123) pg/mL (p = 0.55). The CD40s level at week 12 in non-responders was slightly inferior to that of the responders: median 193 (168-331) versus 413 (281-512) pg/mL (p = 0.08). CONCLUSION: We did not observe a better vaccine response with the PMMA membrane compared to high-flux polysulfone. The PMMA membrane did not decrease the CD40s more than the polysulfone membrane probably because the titre was previously low in the 2 groups.

Vitamin E as a functional and biocompatibility modifier of synthetic hemodialyzer membranes: an overview of the literature on vitamin E-modified hemodialyzer membranes.

Along with one century of history, research has provided many solutions for hemodialysis (HD) biomaterials, encompassing several generations of copolymers that have found wide application in the development of hollow-fiber dialyzer membranes. Polysulfone-based biomaterials have gained increasing consideration and are now the gold standard in the production of biocompatible hemodialyzers. However, even the highest biocompatibility now available cannot exclude that dialyzer membranes and the overall extracorporeal circulation may produce at the subclinical level immunoinflammatory reactions and thus an increased cardiovascular risk of patients on regular HD therapy. The lipophilic antioxidant and radical scavenger vitamin E has been used (as α-tocopherol) to modify cellulosic and synthetic hollow-fiber membranes with the ultimate goal to neutralize harmful reactive species and to mimic lipid structures of blood cell plasmalemma and lipoprotein particles. Besides filtration and biocompatibility, this modifier has introduced a third function of dialyzer membranes, namely 'antioxidant bioactivity'. Vitamin E can also serve as a template molecule to produce synthetic redox-active and -silent (non-antioxidant) modifiers for future generations of dialyzer membranes. This mini-review article describes the evolution of vitamin E-derived copolymers as a generation of biomaterials that has offered a clinical challenge and still represents a chance to further improving the quality of HD therapy.

Low Fouling, Peptoid-Coated Polysulfone Hollow Fiber Membranes-the Effect of Grafting Density and Number of Side Chains.

The development of low fouling membranes to minimize protein adsorption has relevance in various biomedical applications. Here, electrically neutral peptoids containing 2-methoxyethyl glycine (NMEG) side chains were attached to polysulfone hollow fiber membranes via polydopamine. The number of side chains and grafting density were varied to determine the effect on coating properties and the ability to prevent fouling. NMEG peptoid coatings have high hydrophilicity compared to unmodified polysulfone membranes. The extent of biofouling was evaluated using bovine serum albumin, as well as platelet adhesion. The results suggest that both the number of side chains and grafting density play a role in the surface properties that drive biofouling. Protein adsorption decreased with increasing peptoid grafting density and is lowest above a critical grafting density specific to peptoid chain length. Our findings show that the optimization of grafting density and hydration of the surface are important factors for achieving the desired antifouling performance.

A highly permeable zinc-based MOF/polyphenylsulfone composite membrane with elevated antifouling properties.

In this study, for the first time, a highly permeable composite membrane was constructed by incorporating a zinc-based metal-organic framework (Zn-MOF) in a polyphenylsulfone matrix for the elevation of antifouling properties. Owing to the hydrophilic nature and high surface charge, this membrane demonstrated effective bovine serum albumin (a model protein) rejection and antifouling characteristics.

Renewable antibacterial and antifouling polysulfone membranes incorporating a PEO-grafted amphiphilic polymer and N-chloramine functional groups.

Functionalized polysulfone (PSf) membranes with combined antibacterial and antifouling properties were fabricated by incorporating a poly(ethyleneoxide)-grafted (PEO-grafted) amphiliic polymer. Both antifouling and antibacterial groups were easily introduced onto the membrane surfaces through non-solvent induced phase separon process and a simple chlorination process. It was observed that the functionalized membranes were effectivatie in resisting both protein absorption and bacterial adhesion. Furthermore, the functionalized membrane (M3-Cl) showed mostly suppressed irreversible flux decline and a 97% flux recovery ratio after simple washing during the separation process, indicating excellent antifouling properties. Meanwhile, the functionalized PSf membrane exhibited efficient biocidal activity against E. coli and S. aureus. These modified functionalized PSf membranes also displayed outstanding properties in inhibiting the formation of biofilm. Moreover, the antibacterial feature was renewable by a simple process.

Improved antifouling potential of polyether sulfone polymeric membrane containing silver nanoparticles: self-cleaning membranes.

A new strategy to enhance the antifouling potential of polyether sulfone (PES) membrane is presented. Chemically synthesized silver nanoparticles (AgNPs) were used to prepare a mixed-matrix PES membrane by the phase inversion technique. Primarily, AgNPs synthesis was confirmed by surface plasmon resonance at 410-430 nm using UV-Visible spectroscopy. X-ray diffraction analysis revealed that AgNPs were crystalline with a diameter of 21 ± 2 nm. Furthermore, PES membranes were characterized by energy dispersive X-ray spectroscopy to confirm the incorporation of AgNPs in membranes. Hydrophilicity of the membranes was enhanced, whereas roughness, mechanical strength and biofouling were relatively reduced after embedding the AgNPs. Antibacterial potential of AgNPs was evaluated for E. coli in the disc diffusion and colony-forming unit (CFU) count method. All of the membranes were assessed for antifouling activity by filtering a control dilution (106 CFU/ml) of E. coli and by counting CFU. Anti-biofouling activity of the membrane was observed with different concentrations of AgNPs. Maximum reduction (66%) was observed in membrane containing 1.5% of AgNPs. The addition of antibiotic ceftriaxone enhanced the antibacterial effect of AgNPs in PES membranes. Our practicable antifouling strategy may be applied to other polymeric membranes which may pave the new way to achieve sustainable and self-cleaning membrane reactors on large scale.

A synergetic analysis method for antifouling behavior investigation on PES ultrafiltration membrane with self-assembled TiO2 nanoparticles.

Fouling of ultrafiltration (UF) membranes is a major impediment for their use in drinking water production. Mixed matrix membranes (MMMs) may have great opportunities in dealing with this challenge due to their hierarchical structures and multiple functionalities. In this study, a synergetic analysis method based on intermolecular adhesion force measurement and fouling process simulation was applied to investigate the fouling mechanism of polyethersulfone (PES) UF membranes containing in situ self-assembled TiO2 nanoparticles (NPs). The fouling resistance behavior and antifouling mechanism of the newly developed composite membranes were investigated with sodium alginate (SA), bovine serum albumin (BSA) and humic acid (HA) as model organic foulants. An improved antifouling effect was conspicuously observed for the composite membranes, expressed by a lower flux decline and significantly better cleaning efficiency. A strong correlation between the self-assembled structure of TiO2 NPs and the antifouling behavior of the composite membrane was observed. A lower magnitude and a narrower distribution of adhesion forces for the composite membrane suggest the effective suppression of foulants adsorption on the clean or fouled membrane. The simulation analysis indicates that the main fouling mechanism was standard blocking and cake filtration, further confirming the superiority of the NPs self-assembled structure in mitigating membrane fouling. This dual analysis method may provide a promising technological support for the application of modified UF membranes with self-assembled NPs in drinking water production.

Synthesis and Characterization of Silver Nanoparticles-Filled Polyethersulfone Membranes for Antibacterial and Anti-Biofouling Application.

BACKGROUND: The membrane processes are interesting and economical techniques for reuse of municipal and industrial wastewater as well as seawater desalination. However their drawbacks can be resumed in the fouling and biofouling due to the deposition and adsorption phenomenon of the components and the development of biofilm on membrane surface. Several studies have focused on the effect of the incorporation of nanoparticles in polymeric membrane matrix on the biofouling properties. Few relevant patents to the topic have been reviewed and cited. METHODS: Polyethersulfone (PES) membranes filled with silver nanoparticles (AgNPs) were prepared by non-solvent induced phase separation (NIPS) process using polyvinylpyrrolidone (PVP) as additive and N-Methyl-2-pyrrolidone (NMP) as solvent. Dope solution compositions, coagulation bath (CB) compositions, time before immersion in CB and casting speed were systematically studied. Membrane structure was characterized by scanning electron microscopy, contact angle, streaming potential measurement and X-ray diffraction (XRD). RESULTS: Membrane performance was assessed by pure water permeability, antifouling property, porosity and mechanical property. Silver nanoparticles (AgNPs) were prepared by the chemical reduction of silver nitrate solution with freshly prepared fructose solution, using PVP as capping agent and NaOH as accelerant and settled using acetone. The synthesized AgNPs were firstly characterized by Dynamic light scattering (DLS) technique, UV-visible spectrophotometer and X-ray diffraction spectroscopy (XRD). Then, we have selected a 15% PES mixed with 15% of PVP dope solution to prepare PESAgNPs blended membranes. CONCLUSION: All the nanocomposite membranes showed superb antibacterial and anti-biofouling performances, indicating that AgNPs in the PES membranes could be an effective approach to minimize membrane biofouling.

Effect of focal adhesion kinase inhibition on osteoblastic cells grown on titanium with different topographies

Abstract Objective The present study aimed to investigate the participation of focal adhesion kinases (FAK) in interactions between osteoblastic cells and titanium (Ti) surfaces with three different topographies, namely, untreated (US), microstructured (MS), and nanostructured (NS). Methodology Osteoblasts harvested from the calvarial bones of 3-day-old rats were cultured on US, MS and NS discs in the presence of PF-573228 (FAK inhibitor) to evaluate osteoblastic differentiation. After 24 h, we evaluated osteoblast morphology and vinculin expression, and on day 10, the following parameters: gene expression of osteoblastic markers and integrin signaling components, FAK protein expression and alkaline phosphatase (ALP) activity. A smooth surface, porosities at the microscale level, and nanocavities were observed in US, MS, and NS, respectively. Results FAK inhibition decreased the number of filopodia in cells grown on US and MS compared with that in NS. FAK inhibition decreased the gene expression of Alp, bone sialoprotein, osteocalcin, and ALP activity in cells grown on all evaluated surfaces. FAK inhibition did not affect the gene expression of Fak, integrin alpha 1 ( Itga1 ) and integrin beta 1 ( Itgb1 ) in cells grown on MS, increased the gene expression of Fak in cells grown on NS, and increased the gene expression of Itga1 and Itgb1 in cells grown on US and NS. Moreover, FAK protein expression decreased in cells cultured on US but increased in cells cultured on MS and NS after FAK inhibition; no difference in the expression of vinculin was observed among cells grown on all surfaces. Conclusions Our data demonstrate the relevance of FAK in the interactions between osteoblastic cells and Ti surfaces regardless of surface topography. Nanotopography positively regulated FAK expression and integrin signaling pathway components during osteoblast differentiation. In this context, the development of Ti surfaces with the ability to upregulate FAK activity could positively impact the process of implant osseointegration.

Inhibition of tobacco bacterial wilt with sulfone derivatives containing an 1,3,4-oxadiazole moiety.

A series of new sulfone compounds containing the 1,3,4-oxadiazole moiety were designed and synthesized. Their structures were identified by (1)H and (13)C nuclear magnetic resonance and elemental analyses. Antibacterial bioassays indicated that most compounds exhibited promising in vitro antibacterial bioactivities against tobacco bacterial wilt at 200 µg/mL. The relationship between structure and antibacterial activity was also discussed. Among the title compounds, 5'c, 5'h, 5'i, and 5'j could inhibit mycelia growth of Ralstonia solanacearum in vitro by approximately 50% (EC(50)) at 39.8, 60.3, 47.9, and 32.1 µg/mL, respectively. Among them, compound 5'j was identified as the most promising candidate due to its stronger effect than that of Kocide 3000 [Cu(OH)(2)] within the same concentration range. Field trials demonstrated that the control effect of compound 5'j against tobacco bacterial wilt was better than that of the commercial bactericide Saisentong. For the first time, the present work demonstrated that sulfone derivatives containing 1,3,4-oxadiazole can be used to develop potential bactericides for plants.

Chromosomal aberrations in leucocyte metaphases of leprosy patients under dapsone therapy

Chromosome analyses were made on leukocyte metaphases of 18 leprosy patients who were ingesting daily doses of 50 mg or 100 mg of DDS and of 40 healthy individuals used for control. These analyses have shown that the proportion of numerical chromosomal aberrations in the leukocyte metaphases of the leprosy patients did not differ significantly from that observed in the cells of the controls. In contrast, the frequency of cells with chromatid or chromosome breaks and gaps was significantly increased in the leukocytesof leprosy patients. Multiple regression analysis applied to the data recorded has shown that the increase of breaks and gaps in the chromosomes of leprosy patients can not be attributed to age, years under sulfonetherapy or to concentration of DDS in blood.

Lepra tuberculóide reacional. Localização pouco comum de amiotrafias. Regressão das manifestações cutâneas após tratamento com sulfa-metoxipiridina

O A. estudou um caso de lepra tuberculóide reacional que apresentava predominância de manifestações de nevrite do antebraço direito, com posterior aparecimento da máculas na articulação do punho e dorso da mão do mesmo lado, com edema acentuado da mão. Na região infra-escapular esquerda apresentava lesão idêntica à do punho. O caso foi tratado com sulfametoxipiridazina durante 15 dias; o resultado favorável pode ser apreciado pelas fotos que ilustram o trabalho.