Biochemical comparison of 8 h haemodialysis and 4 h haemodiafiltration, and two dialysis membranes, in a randomized cross-over trial.

AIM: Extended-hours haemodialysis has long been regarded as the optimal form of dialysis for solute clearance. With emerging benefits of haemodiafiltration, we wanted to compare these two head-to-head. METHODS: In this randomized cross-over trial, we recruited existing nocturnal haemodialysis patients, who had not been hospitalized in the prior 3 months. After a baseline 8 h haemodialysis session, subjects were randomized to either 2 weeks of 8 h haemodialysis or 4 h haemodiafiltration with cross-over to the alternative treatment after a 2-week washout period. Subjects were additionally randomized to the Fresenius FX80 or Nipro Elisio in a parallel design. Blood and dialysate samples were collected at baseline and at the end of both study periods. RESULTS: Twelve patients completed the study. Mean (SD) age and body mass index were 55.1 ± 11.5 years and 36.4 ± 10.8, respectively. Urea and creatinine reduction ratios were higher with extended-hours haemodialysis compared to haemodiafiltration (difference 14.0%, 95% CI = 10.6, 17.3; P < 0.001 and 9.1%, 95% CI = 11.0, 7.2; P < 0.001). Fibroblast growth factor 23 (FGF23) clearance was superior with haemodiafiltration (difference 20.1%, 95% CI = 8.7, 31.6; P = 0.001). No difference was seen in reduction ratios for phosphate, retinol binding protein, alpha-1-microglobulin, beta-2-microglobulin and fetuin with both modalities. Compared to Nipro Elisio, Fresenius FX80 dialyser achieved higher beta-2-microglobulin clearance (Period 1: difference 7.8%, 95% CI = 1.3, 14.4; P = 0.02, Period 2:7.5%, 95% CI = 1.0, 14.1; P = 0.02). CONCLUSIONS: Small solute clearance was superior with extended-hours haemodialysis while haemodiafiltration enhanced FGF23 clearance. Beta-2-microglobulin clearance was improved with Fresenius FX80 dialyser, but this difference is unlikely to be clinically significant.

Cations induce shape remodeling of negatively charged phospholipid membranes.

The divalent cation Ca2+ is a key component in many cell signaling and membrane trafficking pathways. Ca2+ signal transduction commonly occurs through interaction with protein partners. However, in this study we show a novel mechanism by which Ca2+ may impact membrane structure. We find an asymmetric concentration of Ca2+ across the membrane triggers deformation of membranes containing negatively charged lipids such as phosphatidylserine (PS) and phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2). Membrane invaginations in vesicles were observed forming away from the leaflet with higher Ca2+ concentration, showing that Ca2+ induces negative curvature. We hypothesize that the negative curvature is produced by Ca2+-induced clustering of PS and PI(4,5)P2. In support of this notion, we find that Ca2+-induced membrane deformation is stronger for membranes containing PI(4,5)P2, which is known to more readily cluster in the presence of Ca2+. The observed Ca2+-induced membrane deformation is strongly influenced by Na+ ions. A high symmetric [Na+] across the membrane reduces Ca2+ binding by electrostatic shielding, inhibiting Ca2+-induced membrane deformation. An asymmetric [Na+] across the membrane, however, can either oppose or support Ca2+-induced deformation, depending on the direction of the gradient in [Na+]. At a sufficiently high asymmetric Na+ concentration it can impact membrane structure in the absence of Ca2+. We propose that Ca2+ works in concert with curvature generating proteins to modulate membrane curvature and shape transitions. This novel structural impact of Ca2+ could be important for Ca2+-dependent cellular processes that involve the creation of membrane curvature, including exocytosis, invadopodia, and cell motility.

Effects of self-ligating brackets on oral hygiene and discomfort: a systematic review and meta-analysis of randomized controlled clinical trials.

BACKGROUND: Self-ligating brackets (SLBs) are widely adopted in clinic owing to their claimed superiorities. Here, we collected and analysed all randomized controlled clinical trials (RCTs) comparing SLBs with conventional brackets (CBs) and thereby investigated whether SLBs can relieve discomfort or promote oral hygiene. METHODS: Electronic databases including MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, World Health Organization International Clinical Trials Registry Platform, Chinese BioMedical Literature Database and the China National Knowledge Infrastructure were searched to find out RCTs comparing active or passive SLBs with CBs. Two reviewers extracted the data and assessed risks of bias independently. Any disagreement between them was resolved through discussion with a third reviewer. Meta-analysis was conducted on Review Manager 5.3. RESULTS: A total of 12 RCTs with 575 participants were included, and eight of the trials were synthesized quantitatively. Two trials were assessed as low risk of bias, whereas others as unclear risk of bias. Passive SLBs and CBs are not significantly different in plaque control. SLBs and CBs are not significantly different in discomfort reduction at any of four time points (4 h, 24 h, 3 days and 7 days). CONCLUSIONS: Clinical evidences from existing RCTs suggest that SLBs do not outperform CBs in reliving discomfort or promoting oral health in clinic.

Influence of the chloride ion concentration on the corrosion of high-purity Mg, ZE41 and AZ91 in buffered Hank's solution.

This research studied the influence of the chloride ion concentration on the corrosion behaviour of high-purity magnesium (Mg) and two Mg alloys in Hank's solution, using hydrogen evolution and weight loss. A buffer based on CO2 and NaHCO3 was used to maintain the pH constant. The corrosion behaviour was governed by a partially protective surface film, and film breakdown by the chloride ions. The carbonated calcium phosphate layer that formed in Hank's solution was important in determining the protective properties of the surface film.

New Monomer Capable of Dual Chemical Binding with Dentin to Improve Bonding Durability.

The water-rich nature of the dentin bonding microenvironment, coupled with the stresses on the bonding interface, contributes to the hydrolytic degradation of the hybrid layer, resulting in a decline in bonding durability and, ultimately, restoration failure. Currently, the 3-step etch-and-rinse technique remains the gold standard for dentin bonding, and the bonding mechanism mainly involves a physical interaction with little chemical bonding. In this study, we have developed a siloxane-modified polyurethane monomer (SPU) with acrylate and siloxane modifications that chemically binds to both collagen and hydroxyapatite in dentin. Formulated as a bisphenol A-glycidyl methacrylate alternative, the SPU monomer-based adhesive was designed to improve dentin bonding quality and durability. Attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscope, and hydroxyproline release assays were performed on SPU-treated collagen, hydroxyapatite, and acid-etched dentin slices to dentin. The physicochemical properties of the configured SPU adhesives were profiled for polymerization behavior, water contact angle, and tensile strain and strength. The bonding effectiveness was assessed through micro-tensile strength, nano-leakage tests conducted on the bonded samples before and after thermal cycle aging. Finally, we further conducted in vivo and in vitro experiments to assess the biocompatibility of adhesives. The results showed that the siloxane groups of SPU monomer could covalently bind to dentin collagen and hydroxyapatite. The incorporation of SPU in the adhesive led to a significant increase in adhesive polymerization (P < 0.05) and tensile strain at break up to 134.11%. Furthermore, the SPU adhesive significantly improved dentin bond strength (P < 0.05), reduced interfacial nano-leakage (P < 0.05), and displayed good biocompatibility. In conclusion, the application of SPU, which achieves dual chemical bonding with dentin, can improve the quality of the hybrid layer, buffer the interfacial stresses, enhance the interfacial resistance to hydrolysis, and provide a feasible strategy to extend the service life of adhesive restorations.

Effect of Collagen-Reactive Functional Monomer on Etch-and-Rinse Adhesives.

In this study, we evaluated a novel functional monomer (4-formylphenyl acrylate [FA]) that can specifically and covalently bind to the dentin collagen matrix as a potential alternative hydrophobic diluent-like monomer for improving the durability of dentin bonding. Experimental adhesives with different FA contents (0%, 10%, 20%, and 30%) were evaluated as partial substituents for the hydrophilic monomer 2-hydroxyethyl methacrylate, with the commercial adhesive One-Step (Bisco, Inc.) employed as the positive control. Their degree of conversion, viscosity, hydrophobicity, mechanical properties, and water absorption/solubility were measured as the comprehensive characterization. In situ zymographic assays were performed to determine the extent to which FA inhibits the endogenous hydrolytic activity of dentin. Finally, the bonding performances of the novel adhesives were evaluated with microtensile strength tests and scanning electron microscopy. The results showed that the incorporation of FA significantly improved the mobility of experimental adhesives attributable to the dilution property of FA. In contrast to the possible compromised rate of polymerization by hydroxyethyl methacrylate, FA exhibited typical characteristics of favorable copolymerization with polymerizable monomers in adhesives and improved the degree of conversion of experimental adhesives. The rigidity and hydrophobic properties of the phenyl framework of the FA molecule conferred superior mechanical properties and hydrolysis resistance to the novel experimental adhesives. An inhibitory effect on gelatinolytic activities within the hybrid layer was also observed in the in situ zymographic assays, even at a low FA concentration (10%). In conjunction with the significantly improved infiltration found via scanning electron microscopy, the experimental adhesives containing FA possessed significantly better-maintained microtensile strength, even after aging. Thus, the incorporation of this novel monomer endowed the experimental adhesives with multiple enhanced functionalities. These remarkable advantages highlight the suitability of the monomer for further applications in clinical practice.

A Novel Chemical Binding Primer to Improve Dentin Bonding Durability.

The dentin collagen matrix that is not completely enveloped by resin adhesive is vulnerable to degradation by intrinsic collagenases during the etch-and-rinse process, which contributes to the deterioration of the bonding interface. Current commercial adhesives have no functional components that can form covalent bonds to the dentin collagen matrix. In this study, a photocurable aldehyde, 4-formylphenyl acrylate (FA), was synthesized and for the first time applied as a primer in adhesive dentistry to covalently bind to collagen. Experimental groups with different concentrations of FA (1%, 3%, 5%, 7%, 9%) were prepared as primers. The cytotoxicity was evaluated by live/dead-cell staining and thiazolyl blue tetrazolium bromide assay. The interaction of FA with collagen was examined by attenuated total reflection Fourier transform infrared spectroscopy, hydroxyproline release under the degradation of type I collagenase, and thermogravimetric analysis. An optimal group was selected based on the degree of conversion of 2 universal adhesives and further divided depending on the treatment time (20 s, 30 s, 1 min, 2 min). The bonding performances were evaluated by microtensile strength before and after aging. Finally, the bonding interface was observed under confocal laser scanning microscopy and scanning electron microscope. The results indicated that FA demonstrated good biocompatibility, dentin modification capability, and infiltration. It not only effectively cross-linked dentin collagen to improve its stability against enzymatic hydrolysis and modify the adhesive interface but also potentially acted as a diluting monomer to induce deep penetration of adhesive resin monomers into the dentin. The bonding strength after aging was improved without jeopardizing the degree of conversion of 2 commercial adhesives. Such prominent advantages of using FA to improve the bonding performance promotes its further application in adhesive dentistry.

Submicrometer intracellular chemical optical fiber sensors.

A thousandfold miniaturization of immobilized optical fiber sensors, a millionfold or more sample reduction, and at least a hundredfold shorter response time, all simultaneously, were achieved by combining nanofabricated optical fiber tips with near-field photopolymerization. Specifically, pH optical fiber sensors were prepared with internal calibration, making use of the differences in both fluorescence and absorption of the acidic and basic dye species. The submicrometer sensors have excellent detection limits, as well as photostability, reversibility, and millisecond response times. Successful applications include intracellular and intraembryonic measurements. Potential applications include spatially and temporally resolved chemical analysis and kinetics inside single biological cells and their substructures.

Bioactive titanium implant surfaces with bacterial inhibition and osteoblast function enhancement properties.

Infection in orthopedic implant surgery is a serious complication and a major cause of implant failure. Upon implant insertion, a contest between microbial colonization and tissue integration of the implant surface ensues. This race for the surface determines the probability of tissue integration or infection, and the surface properties of the substrate have an important role to play in determining the outcome. A number of strategies have been developed for the modification of implant surfaces to promote bone cell (osteoblast) functions and inhibit bacterial adhesion and growth. In this article, a review is given of these surface modification strategies, in particular those which can achieve the dual aim of bacterial inhibition and simultaneous enhancement of osteoblast functions.Surfaces of these types can be expected to have excellent potential for orthopedic applications.

Mechanical properties, in vitro corrosion resistance and biocompatibility of metal injection molded Ti-12Mo alloy for dental applications.

A biocompatible Ti-12Mo alloy was fabricated by metal injection moulding (MIM) using non-spherical titanium, molybdenum powders and a purposely designed binder. The density, microstructure and tensile properties were characterized. This was followed by a detailed assessment of its in vitro corrosion and biocompatibility performances, compared with that of two commonly used titanium-based materials extra low interstitial (ELI) Ti-6Al-4V and commercially pure (CP) titanium. The MIM-fabricated Ti-12Mo alloy can achieve a wide range of mechanical properties through controlling sintering process. Specimens sintered at 1400 °C are characterized by fairly uniform near-ß microstructure and high relative density of 97.6%, leading to the highest tensile strength of 845.3 ±â€¯21 MPa and elongation of 4.15 ±â€¯0.2% while the highest elastic modulus of 73.2 ±â€¯5.1 GPa. Owing to the formation of protective TiO2-MoO3 passive film, the MIM-fabricated Ti-12Mo alloy exhibits the highest corrosion resistance including the noblest corrosion potential, the lowest corrosion current density and the highest pitting potential in four different electrolytes. The in vitro cytotoxicity test suggests that the MIM-fabricated Ti-12Mo alloy displays no adverse effect on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6Al-4V or CP Ti. These properties together with its easy net-shape manufacturability make Ti-12Mo an attractive new dental implant alloy.

In vitro antibacterial and cytotoxicity assay of multilayered polyelectrolyte-functionalized stainless steel.

Infection of implanted materials by bacteria constitutes one of the most serious complications following prosthetic and implant surgery. In the present study, a new strategy for confering stainless steel with antibacterial property via the alternate deposition of quaternized polyethylenimine (PEI) or quaternized polyethylenimine-silver complex and poly(acrylic acid) (PAA) was investigated. The success of the deposition of the polyelectrolyte multilayers (PEM) and its chemical nature was investigated by static water contact angle and X-ray photoelectron spectroscopy (XPS), respectively. The antibacterial activity was assessed using Escherichia coli (E. coli, a gram-negative bacterium) and Staphylococcus aureus (S. aureus, a gram-positive bacterium). The inhibition of E. coli and S aureus growth on the surface of functionalized films was clearly shown using the LIVE/DEAD Baclight bacterial viability kits and fluorescence microscopy. The cytotoxicity of the PEM to mammalian cells, evaluated by the MTT assay, was shown to be minimal and long-term antibacterial efficacy can be maintained. These results indicate new possibilities for the use of such easily built and functionalized architectures for the functionalization of surfaces of implanted medical devices.

Two-stage operation to treat destructive midfoot tuberculosis: 14 cases experience.

INTRODUCTION: Tuberculosis (TB) in midfoot is often secondary to tuberculosis elsewhere in the body. The experience and literatures to treat midfoot tuberculosis are rare. Up until now, no successful method is reported to treat midfoot tuberculosis. HYPOTHESIS: Stage surgery is an effective method to treat midfoot bone TB. MATERIAL AND METHODS: Between January 2008 to January 2011, 14 patients who were diagnosed midfoot tuberculosis and suffered stage operation were enrolled. All the patients had been diagnosed definitely relying on imaging examination and laboratory tests preoperatively. Two-stage operation was performed to all patients. At the first stage, TB tissue and infective tissue were completely removed and replaced by antibiotic bone cement. Normal foot length and arch would be restored and maintained by K-wires and external fixators. At the second stage, autologous iliac and allogeneic bone graft were used to replace bone cement and by fixed by locking plates. American Orthopaedic Foot and Ankle Society (AOFAS), SF-36 and visual analogue scale (VAS) pain score were recorded at the last follow-up. RESULTS: The average bone union time was 3.8 (range 3-6) months. There is no case of local recurrence or skin sinus. Neither implant broken nor screw loosen was present in this study. The AOFAS score was increased from 51.7±6.8 (range 43-61) preoperatively to 82.9±3.9 (range 76-90) postoperatively (P<0.001). The SF-36 score increased from 46.1±6.1 preoperatively to 83.1±5.4 postoperatively (P<0.001). The VAS score decreased from 6.1±1.1 preoperatively to 1.4±0.9 points postoperatively (P<0.001). DISCUSSION: Stage operation is an effective treatment to stage III, IV midfoot tuberculosis. LEVELS OF EVIDENCE: Level IV, retrospective.

[Effects of high fluoride intake on the fluoride of femora, teeth and some biochemical indexes in rats].

In order to approach practicable indexes for assessing the effects of the products which are intended to be used to prevent endemic fluorosis, Wistar rats were fed with fluoridated water(50 mg/L) for four weeks. After only one week treated with fluoride, a higher activity of NAG(N-acetyl-beta-D-glucosaminidase) in urine, ChE(cholinesterase) in blood and increased urinary excretion of fluoride (compared with the control, P < 0.01) were observed, and these changes were lasted to the end of the fourth week of the study, but hydroxyproline in serum and urine had not been changed in both groups. After four weeks, the fluoride levels in the femora and teeth of fluoride treated group were ten times higher than that of the control group. According to the results, fluoride in bones and teeth must be taken as key indexes, the activities of NAG in urine and ChE in blood should be taken into consideration for assessing the effects of fluoride protagonist.

[Vitrectomy for pseudophakic retinal detachment].

OBJECTIVE: To study the method of vitrectomy for treatment of pseudophakic retinal detachment. METHODS: 32 pseudophakic retinal detachment eyes were treated with vitrectomy, primary vitrectomy in 11 eyes (34.4%), vitrectomy after conventional buckling failure in 21 eyes (65.6%), combined with silicone oil 10 eyes (31.3%), removal of intraocular lens 12 eyes (37.5%). All eyes had passed the 6 months to 5 years of follow-up examination. RESULTS: Intra-operative new retinal breaks were identified in 7 eyes (21.9%). The retinal total reattachment was in 25 eyes (78.1%); part reattachment was in 4 eyes (12.5%), and their visual acuity was improved than that before the operation. Due to severe proliferative vitreoretinopathy (PVR), failure occurred in 3 eyes. CONCLUSIONS: The main advantage of vitrectomy is the better intra-operative sight to the peripheral retinal breaks, removal of retinal traction and the low rate of PVR after vitrectomy. Vitrectomy for complicated type of pseudophakic retinal detachment can improve the success rate of the retinal detachment surgery and the visual acuity outcome.

Synthetic optimization of air turbine for dental handpieces.

A synthetic optimization of Pelton air turbine in dental handpieces concerning the power output, compressed air consumption and rotation speed in the mean time is implemented by employing a standard design procedure and variable limitation from practical dentistry. The Pareto optimal solution sets acquired by using the Normalized Normal Constraint method are mainly comprised of two piecewise continuous parts. On the Pareto frontier, the supply air stagnation pressure stalls at the lower boundary of the design space, the rotation speed is a constant value within the recommended range from literature, the blade tip clearance insensitive to while the nozzle radius increases with power output and mass flow rate of compressed air to which the residual geometric dimensions are showing an opposite trend within their respective "pieces" compared to the nozzle radius.

Receptor modelling of airborne particulate matter in the vicinity of a major steelworks site.

In this study, the Multilinear Engine (ME-2) receptor model was applied to speciated particulate matter concentration data collected with two different measuring instruments upwind and downwind of a steelworks complex in Port Talbot, South Wales, United Kingdom. Hourly and daily PM samples were collected with Streaker and Partisol samplers, respectively, during a one month sampling campaign between April 18 and May 16, 2012. Daily samples (PM10, PM2.5, PM2.5-10) were analysed for trace metals and water-soluble ions using standard procedures. Hourly samples (PM2.5 and PM2.5-10) were assayed for 22 elements by Particle Induced X-ray Emission (PIXE). PM10 data analysis using ME-2 resolved 6 factors from both datasets identifying different steel processing units including emissions from the blast furnaces (BF), the basic oxygen furnace steelmaking plant (BOS), the coke-making plant, and the sinter plant. Steelworks emissions were the main contributors to PM10 accounting for 45% of the mass when including also secondary aerosol. The blast furnaces were the largest emitter of primary PM10 in the study area, explaining about one-fifth of the mass. Other source contributions to PM10 were from marine aerosol (28%), traffic (16%), and background aerosol (11%). ME-2 analysis was also performed on daily PM2.5 and PM2.5-10 data resolving 7 and 6 factors, respectively. The largest contributions to PM2.5-10 were from marine aerosol (30%) and blast furnace emissions (28%). Secondary components explained one-half of PM2.5 mass. The influence of steelworks sources on ambient particulate matter at Port Talbot was distinguishable for several separate processing sections within the steelworks in all PM fractions.

Effect of growth phase on harvesting characteristics, autoflocculation and lipid content of Ettlia texensis for microalgal biodiesel production.

The effect of growth phase on the recovery of the autoflocculating microalgae Ettlia texensis was studied. In the stationary phase, 90% recovery was achieved after 3h settling. Scanning electron microscopic pictures revealed that extracellular polymeric substances (EPS) on the cell surface were involved in autoflocculation. During the stationary phase an increase of the protein fraction in the EPS was observed while the total fatty acids content increased. The autoflocculating properties of E. texensis combined with favourite fatty acid content and composition make this microalgae an excellent candidate for biodiesel production if harvested at the end of the stationary phase.

Angiopoietin-2 inhibits the growth of tongue carcinoma without affecting expression of vascular endothelial growth factor.

Angiopoietin-2 (Ang-2) has been identified as an important factor in tumour angiogenesis through its action in blocking the stabilizing actions of Ang-2 and leading to new tumour vessel growth in the presence of vascular endothelial growth factor (VEGF). In the authors' previous study, over-expression of Ang-2 in Tca8113 tongue tumour cells inhibited growth. The current study aims to clarify the mechanisms of Ang-2-mediated tumour growth inhibition and its role in the regulation of VEGF expression. These studies used tumours derived from Ang-2-transfected Tca8113 cells injected into nude mice. The results showed that Ang-2-transfected tumours displayed aberrant angiogenic vessels with few associated smooth muscle cells. No detectable differences in VEGF expression were observed between Ang-2-transfected and parental tumours. Tumours produced by the Ang-2 transfection also had a higher apoptosis index and lower tumour cell proliferative index than tumours in the control groups. These observations suggest that enhanced expression of Ang-2 has no effect on VEGF expression and results in tumour vessel regression and inhibition of tumour growth.

Structural stability and bioapplicability assessment of hyaluronic acid-chitosan polyelectrolyte multilayers on titanium substrates.

Since bacterial infections associated with implants remain a major cause of their failure, this study investigated the use of polyelectrolyte multilayers (PEMs) comprising hyaluronic acid (HA) and chitosan (CH) to confer antibacterial properties on titanium (Ti). HA and CH were deposited on Ti using the layer-by-layer deposition method. The antibacterial efficacy of the functionalized Ti substrates was assessed using Escherichia coli and Staphylococcus aureus. The number of adherent bacteria on Ti functionalized with HA and CH PEMs was up to an order of magnitude lower than that on the pristine Ti. The effects of chemical crosslinking of the PEMs on the structural stability and antibacterial efficacy were investigated. The chemical crosslinking of the PEMs imparts greater structural stability and preserves the antibacterial properties even after the prolonged immersion in phosphate-buffered saline. The cytotoxicity of the PEMs to osteoblasts was evaluated using the MTT assay. The results showed that the biocompatible and long-lasting antibacterial nature of the functionalized Ti substrates offers great potential for reducing implant-associated infections.