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Sample records for isocratic elution utilizing

  1. Performance of HPLC/MS microchips in isocratic and gradient elution modes.

    PubMed

    Ehlert, Steffen; Trojer, Lukas; Vollmer, Martin; van de Goor, Tom; Tallarek, Ulrich

    2010-03-01

    We analyzed the chromatographic performance of particle-packed, all-polyimide high-performance liquid chromatography/mass spectrometry (HPLC/MS) microchips in terms of their hydraulic permeabilities and separation efficiency under isocratic and gradient elution conditions. The separation channels of the chips (with ca 50 microm x 75 microm trapezoidal cross-section and a length of 43 mm) were slurry packed with either 3.5 or 5 microm spherical porous C18-silica particles. A custom-built holder enveloped the chip during packing to prevent channel deformation and delamination from high pressures. It is shown that the packing conditions significantly impact the packing density of the HPLC/MS chips, which determines their performance in both, isocratic and gradient elution modes. Even with steep solvent gradients, peak shape and chromatographic resolution for the densely packed HPLC/MS chips are much improved. Our data show that the analytical power of the HPLC/MS chip is limited by the quality of the chromatographic separation. PMID:20209581

  2. Thermodynamic modeling of protein retention in mixed-mode chromatography: An extended model for isocratic and dual gradient elution chromatography.

    PubMed

    Lee, Yi Feng; Graalfs, Heiner; Frech, Christian

    2016-09-16

    An extended model is developed to describe protein retention in mixed-mode chromatography based on thermodynamic principles. Special features are the incorporation of pH dependence of the ionic interaction on a mixed-mode resin and the addition of a water term into the model which enables one to describe the total number of water molecules released at the hydrophobic interfaces upon protein-ligand binding. Examples are presented on how to determine the model parameters using isocratic elution chromatography. Four mixed-mode anion-exchanger prototype resins with different surface chemistries and ligand densities were tested using isocratic elution of two monoclonal antibodies at different pH values (7-10) and encompassed a wide range of NaCl concentrations (0-5M). U-shape mixed-mode retention curves were observed for all four resins. By taking into account of the deprotonation and protonation of the weak cationic functional groups in these mixed-mode anion-exchanger prototype resins, conditions which favor protein-ligand binding via mixed-mode strong cationic ligands as well as conditions which favor protein-ligand binding via both mixed-mode strong cationic ligands and non-hydrophobic weak cationic ligands were identified. The changes in the retention curves with pH, salt, protein, and ligand can be described very well by the extended model using meaningful thermodynamic parameters like Gibbs energy, number of ionic and hydrophobic interactions, total number of released water molecules as well as modulator interaction constant. Furthermore, the fitted model parameters based on isocratic elution data can also be used to predict protein retention in dual salt-pH gradient elution chromatography. PMID:27554024

  3. Isocratic and gradient elution in micellar liquid chromatography with Brij-35.

    PubMed

    Peris-García, Ester; Ortiz-Bolsico, Casandra; Baeza-Baeza, Juan José; García-Alvarez-Coque, María Celia

    2015-06-01

    Polyoxyethylene(23)lauryl ether (known as Brij-35) is a nonionic surfactant, which has been considered as an alternative to the extensively used in micellar liquid chromatography anionic surfactant sodium lauryl (dodecyl) sulfate, for the analysis of drugs and other types of compounds. Brij-35 is the most suitable nonionic surfactant for micellar liquid chromatography, owing to its commercial availability, low cost, low toxicity, high cloud temperature, and low background absorbance. However, it has had minor use. In this work, we gather and discuss some results obtained in our laboratory with several β-blockers, sulfonamides, and flavonoids, concerning the use of Brij-35 as mobile phase modifier in the isocratic and gradient modes. The chromatographic performance for purely micellar eluents (with only surfactant) and hybrid eluents (with surfactant and acetonitrile) is compared. Brij-35 increases the polarity of the alkyl-bonded stationary phase and its polyoxyethylene chain with the hydroxyl end group allows hydrogen-bond interactions, especially for phenolic compounds. This offers the possibility of using aqueous solutions of Brij-35 as mobile phases with sufficiently short retention times. The use of gradients of acetonitrile to keep the concentration of Brij-35 constant is another interesting strategy that yields a significant reduction in the peak widths, which guarantee high resolution. PMID:25866292

  4. Simultaneous determination of various bioactive redox components in Shuang-Huang-Lian preparations using a novel three-channel isocratic elution liquid chromatography with electrochemical detection system.

    PubMed

    Chen, Liangmian; Hakamata, Hideki; Kusu, Fumiyo; Wang, Zhimin; Gao, Huimin; Kotani, Akira

    2014-07-01

    A novel three-channel isocratic elution high performance liquid chromatography with electrochemical detection (3LC-ECD) system was developed for the simultaneous determination of various bioactive redox components in Shuang-Huang-Lian (SHL) preparations. This 3LC-ECD system consists of three isocratic elution flow ways, two switching valves, four columns, and three electrochemical detectors. Through alternately rotating switching valves to change the elution flow way, six caffeoylquinic acids, four flavonoids, and one phenylethanoid glycoside compound were simultaneously determined within 70 min by the present 3LC-ECD method, in which three compounds of protocatechuic aldehyde, propyl gallate, and kaempferol were used as internal standards. The results demonstrated that the present 3LC-ECD method has achieved desired linearity (r>0.999), precision (relative standard deviation <2.5%), accuracy (recovery, 95.6-103.6%), and high sensitivity (limit of detection, 0.11-0.90 ng/mL). In addition, we successfully determined the contents of these 11 bioactive redox components in 14 batches of SHL oral liquid and 12 batches of SHL lyophilized powder for injection produced by different manufacturers in China. PMID:24657677

  5. Normalized Elution Time Prediction Utility

    Energy Science and Technology Software Center (ESTSC)

    2011-02-17

    This program is used to compute the predicted normalized elution time (NET) for a list of peptide sequences. It includes the Kangas/Petritis neural network trained model, the Krokhin hydrophobicity model, and the Mant hydrophobicity model. In addition, it can compute the predicted strong cation exchange (SCX) fraction (on a 0 to 1 scale) in which a given peptide will appear.

  6. The utility of accurate mass and LC elution time information in the analysis of complex proteomes

    SciTech Connect

    Norbeck, Angela D.; Monroe, Matthew E.; Adkins, Joshua N.; Anderson, Kevin K.; Daly, Don S.; Smith, Richard D.

    2005-08-01

    Theoretical tryptic digests of all predicted proteins from the genomes of three organisms of varying complexity were evaluated for specificity and possible utility of combined peptide accurate mass and predicted LC normalized elution time (NET) information. The uniqueness of each peptide was evaluated using its combined mass (+/- 5 ppm and 1 ppm) and NET value (no constraint, +/- 0.05 and 0.01 on a 0-1 NET scale). The set of peptides both underestimates actual biological complexity due to the lack of specific modifications, and overestimates the expected complexity since many proteins will not be present in the sample or observable on the mass spectrometer because of dynamic range limitations. Once a peptide is identified from an LCMS/MS experiment, its mass and elution time is representative of a unique fingerprint for that peptide. The uniqueness of that fingerprint in comparison to that for the other peptides present is indicative of the ability to confidently identify that peptide based on accurate mass and NET measurements. These measurements can be made using HPLC coupled with high resolution MS in a high-throughput manner. Results show that for organisms with comparatively small proteomes, such as Deinococcus radiodurans, modest mass and elution time accuracies are generally adequate for peptide identifications. For more complex proteomes, increasingly accurate easurements are required. However, the majority of proteins should be uniquely identifiable by using LC-MS with mass accuracies within +/- 1 ppm and elution time easurements within +/- 0.01 NET.

  7. Cost effectiveness of drug eluting coronary artery stenting in a UK setting: cost–utility study

    PubMed Central

    Bagust, A; Grayson, A D; Palmer, N D; Perry, R A; Walley, T

    2006-01-01

    Objective To assess the cost effectiveness of drug eluting stents (DES) compared with conventional stents for treatment of symptomatic coronary artery disease in the UK. Design Cost–utility analysis of audit based patient subgroups by means of a simple economic model. Setting Tertiary care. Participants 12 month audit data for 2884 patients receiving percutaneous coronary intervention with stenting at the Cardiothoracic Centre Liverpool between January 2000 and December 2002. Main outcome measures Risk of repeat revascularisation within 12 months of index procedure and reduction in risk from use of DES. Economic modelling was used to estimate the cost–utility ratio and threshold price premium. Results Four factors were identified for patients undergoing elective surgery (n  =  1951) and two for non‐elective surgery (n  =  933) to predict risk of repeat revascularisation within 12 months. Most patients fell within the subgroup with lowest risk (57% of the elective surgery group with 5.6% risk and 91% of the non‐elective surgery group with 9.9% risk). Modelled cost–utility ratios were acceptable for only one group of high risk patients undergoing non‐elective surgery (only one patient in audit data). Restricting the number of DES for each patient improved results marginally: 4% of stents could then be drug eluting on economic grounds. The threshold price premium justifying 90% substitution of conventional stents was estimated to be £112 (US$212, [euro ]162) (sirolimus stents) or £89 (US$167, [euro ]130) (paclitaxel stents). Conclusions At current UK prices, DES are not cost effective compared with conventional stents except for a small minority of patients. Although the technology is clearly effective, general substitution is not justified unless the price premium falls substantially. PMID:15831599

  8. Hydrogen sulfide production by sulfate-reducing bacteria utilizing additives eluted from plastic resins.

    PubMed

    Tsuchida, Daisuke; Kajihara, Yusuke; Shimidzu, Nobuhiro; Hamamura, Kengo; Nagase, Makoto

    2011-06-01

    In the present study it was demonstrated that organic additives eluted from plastic resins could be utilized as substrates by sulfate-reducing bacteria. Two laboratory-scale experiments, a microcosm experiment and a leaching experiment, were conducted using polyvinyl chloride (PVC) as a model plastic resin. In the former experiment, the conversion of sulfate to sulfide was evident in microcosms that received plasticized PVC as the sole carbon source, but not in those that received PVC homopolymer. Additionally, dissolved organic carbon accumulated only in microcosms that received plasticized PVC, indicating that the dissolved organic carbon originated from additives. In the leaching experiment, phenol and bisphenol A were found in the leached solutions. These results suggest that the disposal of waste plastics in inert waste landfills may result in the production of H(2)S. PMID:21135024

  9. Fatty acids in erythrocytes measured by isocratic HPLC.

    PubMed

    Abushufa, R; Reed, P; Weinkove, C

    1994-09-01

    We developed an isocratic reversed-phase HPLC method to measure arachidonic, palmitoleic, linoleic, eicosatrienoic, oleic, palmitic, and stearic acids from hydrolyzed erythrocytes. Washed erythrocytes were heated in methanol:HCl and the fatty acids extracted into hexane:amyl alcohol. After derivatization with 4-bromomethyl-7-methoxycoumarin, samples diluted in mobile phase (acetonitrile:water, 85:15 by vol) were injected onto a 250 x 4.6 mm C18 column, and the eluted fatty acids were detected fluorometrically. For all analytes, the mean within-batch CV was 8.2% (5.5-10.8%), the mean limit of detection was 7.0 mumol/L, a linear response was maintained up to 400 mumol/L, and results agreed well with those by gas chromatography. The addition of antioxidant (butylated hydroxytoluene) was essential for sample stability. We discuss hydrolysis and extraction times, derivatization temperature, critical steps in chromatography, and concentration units. PMID:8070079

  10. Simple isocratic method for simultaneous determination of caffeine and catechins in tea products by HPLC.

    PubMed

    Fernando, Chamira Dilanka; Soysa, Preethi

    2016-01-01

    Tea is a popular beverage almost all over the world. Many studies show that tea consumption is closely associated with positive health impact. Most of the HPLC methods used for the determination of tea constituents include gradient elution systems which involve expensive instrumentation. The objective of this study was to develop a simple, rapid precise and low cost HPLC method for the separation and quantification of catechins and caffeine in tea (Camellia sinensis). The method utilizes a phenyl column (2.1 × 150 mm) with a UV-detector (280 nm) where excellent chromatographic separation of tea components i.e. gallic acid (GA), caffeine (Caf), epicatechin (EC) and (-)-epigallocatechin gallate (EGCG) was achieved. The isocratic elution system of acetonitrile, glacial acetic acid and deionized water (8:1:91 v/v/v) at a flow rate of 0.5 mL/min was involved. This method produced excellent accuracy and precision. Within run and between run precision was less than 7.5 %. The equations for calibration curves were y = 0.117 (±0.010)x + 0.173 (±0.024), y = 0.100 (±0.003)x + 0.045 (±0.019), y = 0.016 (±0.001)x + 0.006 (±0.004), y = 0.025 (±0.001)x-0.025 (±0.007) for GA, Caf, EC and EGCG respectively. The method validation parameters prove that the method is efficient, a simple and adequate for the quantitative determination of principal components in tea samples. PMID:27429880

  11. Simultaneous analysis of heparosan oligosaccharides by isocratic liquid chromatography with charged aerosol detection/mass spectrometry.

    PubMed

    Ji, Xiaohu; Hu, Guixin; Zhang, Qiongyan; Wang, Fengshan; Liu, Chunhui

    2016-11-01

    Uncovering the biological roles of heparosan oligosaccharides requires a simple and robust method for their separation and identification. We reported on systematic investigations of the retention behaviors of synthetic heparosan oligosaccharides on porous graphitic carbon (PGC) column by HPLC with charged aerosol detection. Oligosaccharides were strongly retained by PGC material in water-acetonitrile mobile phase, and eluted by trifluoroacetic acid occurring as narrow peaks. Addition of small fraction of methanol led to better selectivity of PGC to oligosaccharides than acetonitrile modifier alone, presumably, resulting from displacement of methanol to give different chemical environment at the PGC surface. Van't-Hoff plots demonstrated that retention behaviors highly depended on the column temperature and oligosaccharide moieties. By implementing the optimal MeOH content and temperature, a novel isocratic elution method was successfully developed for baseline resolution and identification of seven heparosan oligosaccharides using PGC-HPLC-CAD/MS. This approach allows for rapid analysis of heparosan oligosaccharides from various sources. PMID:27516280

  12. Refractive index-based detection of gradient elution liquid chromatography using chip-integrated microring resonator arrays.

    PubMed

    Wade, James H; Bailey, Ryan C

    2014-01-01

    Refractive index-based sensors offer attractive characteristics as nondestructive and universal detectors for liquid chromatographic separations, but a small dynamic range and sensitivity to minor thermal perturbations limit the utility of commercial RI detectors for many potential applications, especially those requiring the use of gradient elutions. As such, RI detectors find use almost exclusively in sample abundant, isocratic separations when interfaced with high-performance liquid chromatography. Silicon photonic microring resonators are refractive index-sensitive optical devices that feature good sensitivity and tremendous dynamic range. The large dynamic range of microring resonators allows the sensors to function across a wide spectrum of refractive indices, such as that encountered when moving from an aqueous to organic mobile phase during a gradient elution, a key analytical advantage not supported in commercial RI detectors. Microrings are easily configured into sensor arrays, and chip-integrated control microrings enable real-time corrections of thermal drift. Thermal controls allow for analyses at any temperature and, in the absence of rigorous temperature control, obviates extended detector equilibration wait times. Herein, proof of concept isocratic and gradient elution separations were performed using well-characterized model analytes (e.g., caffeine, ibuprofen) in both neat buffer and more complex sample matrices. These experiments demonstrate the ability of microring arrays to perform isocratic and gradient elutions under ambient conditions, avoiding two major limitations of commercial RI-based detectors and maintaining comparable bulk RI sensitivity. Further benefit may be realized in the future through selective surface functionalization to impart degrees of postcolumn (bio)molecular specificity at the detection phase of a separation. The chip-based and microscale nature of microring resonators also make it an attractive potential detection

  13. Refractive Index-Based Detection of Gradient Elution Liquid Chromatography using Chip-Integrated Microring Resonator Arrays

    PubMed Central

    Wade, James H.; Bailey, Ryan C.

    2014-01-01

    Refractive index-based sensors offer attractive characteristics as non-destructive and universal detectors for liquid chromatographic separations, but a small dynamic range and sensitivity to minor thermal perturbations limit the utility of commercial RI detectors for many potential applications, especially those requiring the use of gradient elutions. As such, RI detectors find use almost exclusively in sample abundant, isocratic separations when interfaced with HPLC. Silicon photonic microring resonators are refractive index-sensitive optical devices that feature good sensitivity and tremendous dynamic range. The large dynamic range of microring resonators allows the sensors to function across a wide spectrum of refractive indices, such as that encountered when moving from an aqueous to organic mobile phase during a gradient elution – a key analytical advantage not supported in commercial RI detectors. Microrings are easily configured into sensor arrays, and chip-integrated control microrings enable real-time corrections of thermal drift. Thermal controls allow for analyses at any temperature and in the absence of rigorous temperature control, obviating extended detector equilibration wait times. Herein, proof of concept isocratic and gradient elution separations were performed using well characterized model analytes (e.g., caffeine, ibuprofen) in both neat buffer and more complex sample matrices. These experiments demonstrate the ability of microring arrays to perform isocratic and gradient elutions under ambient conditions, avoiding two major limitations of commercial RI-based detectors and maintaining comparable bulk RI sensitivity. Further benefit may be realized in the future through selective surface functionalization to impart degrees of post-column (bio)molecular specificity at the detection phase of a separation. The chip-based and microscale nature of microring resonators also makes it an attractive potential detection technology that could be

  14. Elution strategies for reversed-phase high-performance liquid chromatography analysis of sucrose alkanoate regioisomers with charged aerosol detection.

    PubMed

    Lie, Aleksander; Pedersen, Lars Haastrup

    2013-10-11

    A broad range of elution strategies for RP-HPLC analysis of sucrose alkanoate regioisomers with CAD was systematically evaluated. The HPLC analyses were investigated using design-of-experiments methodology and analysed by analysis of variance (ANOVA) and regression modelling. Isocratic elutions, isocratic elutions with increased flow, and gradient elutions with step-down profiles and step-up profiles were performed and the chromatographic parameters of the different elution strategies were described by suitable variables. Based on peak resolutions general resolution deviation for multiple peaks (RDm) was developed for sample-independent evaluation of separation of any number of peaks in chromatographic analysis. Isocratic elutions of sucrose alkanoates showed similar relationships between eluent acetonitrile concentration and retention time for all regioisomers of sucrose caprate and sucrose laurate, as confirmed by evaluation of the curvatures using approximate second derivatives and Kendall rank correlation coefficients. Regression modelling and statistical analysis showed that acetonitrile concentration and flow rate were highly significant for both average adjusted retention time and RDm for sucrose laurate. For both responses the effect of changes in acetonitrile concentration was larger than the effect of changes in flow rate, over the ranges studied. Regression modelling of the step-down gradient profiles for the sucrose alkanoates showed that the eluent acetonitrile concentrations were the overall most significant variables for retention time and separation. The models for average adjusted retention time of sucrose caprate and sucrose laurate showed only a few differences in the significance levels of terms, while the models for RDm showed larger differences between the sucrose alkanoates, in both the number of terms and their significance. Efficiency evaluation of elution strategies, in terms of RDm and analysis time, showed that the best results were

  15. Stochastic approach for an unbiased estimation of the probability of a successful separation in conventional chromatography and sequential elution liquid chromatography.

    PubMed

    Ennis, Erin J; Foley, Joe P

    2016-07-15

    A stochastic approach was utilized to estimate the probability of a successful isocratic or gradient separation in conventional chromatography for numbers of sample components, peak capacities, and saturation factors ranging from 2 to 30, 20-300, and 0.017-1, respectively. The stochastic probabilities were obtained under conditions of (i) constant peak width ("gradient" conditions) and (ii) peak width increasing linearly with time ("isocratic/constant N" conditions). The isocratic and gradient probabilities obtained stochastically were compared with the probabilities predicted by Martin et al. [Anal. Chem., 58 (1986) 2200-2207] and Davis and Stoll [J. Chromatogr. A, (2014) 128-142]; for a given number of components and peak capacity the same trend is always observed: probability obtained with the isocratic stochastic approachisocratic simulations compared to the gradient simulations with the same peak capacity. When the stochastic results are applied to conventional HPLC and sequential elution liquid chromatography (SE-LC), the latter is shown to provide much greater probabilities of success for moderately complex samples (e.g., PHPLC=31.2% versus PSE-LC=69.1% for 12 components and the same analysis time). For a given number of components, the density of probability data provided over the range of peak capacities is sufficient to allow accurate interpolation of probabilities for peak capacities not reported, <1.5% error for saturation factors <0.20. Additional applications for the stochastic approach include isothermal and programmed-temperature gas chromatography. PMID:27286646

  16. Effect of pre- and post-column band broadening on the performance of high-speed chromatography columns under isocratic and gradient conditions.

    PubMed

    Vanderlinden, Kim; Broeckhoven, Ken; Vanderheyden, Yoachim; Desmet, Gert

    2016-04-15

    We report on the results of an experimental and theoretical study of the effect of the extra-column band broadening (ECBB) on the performance of narrow-bore columns filled with the smallest particles that are currently commercially available. Emphasis is on the difference between the effect of ECBB under gradient and isocratic conditions, as well as on the ability to model and predict the ECBB effects using well-established band broadening expressions available from the theory of chromatography. The fine details and assumptions that need to be taken into account when using these expressions are discussed. The experiments showed that, the steeper the gradient, the more pronounced the extra-column band broadening losses become. Whereas the pre-column band broadening can in both isocratic and gradient elution be avoided by playing on the possibilities to focus the analytes on top of the column (e.g. by using the POISe injection method when running isocratic separations), the post-column extra-column band broadening is inescapable in both cases. Inducing extra-column band broadening by changing the inner diameter of the post-column tubing from 65 to 250 μm, we found that all peaks in the chromatogram are strongly affected (around a factor of 1.9 increase in relative peak width) when running steep gradients, while usually only the first eluting peak was affected in the isocratic mode or when running shallow gradients (factor 1.6-1.8 increase in relative peak width for the first eluting analyte). PMID:26987413

  17. Simple Isocratic HPLC Method for Determination of Enantiomeric Impurity in Besifloxacin Hydrochloride.

    PubMed

    Kumar, G Pradeep; Srivastava, Vishal; Khandelwal, Kiran; Kumar, Rajesh; Hiriyanna, S G; Kumar, Ajay; Kumar, Pramod

    2016-09-01

    Besifloxacin is a unique chiral broad-spectrum flouroquinolone used in the treatment of bacterial conjunctivitis. R-form of besifloxacin hydrochloride shows higher antibacterial activity as compared to the S-isomer. Therefore, it is necessary to establish chiral purity. To establish chiral purity a high-performance liquid chromatography (HPLC) method for determination of R-besifloxacin and S-besifloxacin (BES impurity A) was developed and validated for in-process quality control and stability studies. The analytical performance parameters such as linearity, precision, accuracy, specificity, limit of detection (LOD), and lower limit of quantification (LOQ) were determined according to International Council for Harmonization ICH Q2(R1) guidelines. HPLC separation was achieved on Chiralpak AD-H (250 x 4.6 mm, 5 μm) column using n-heptane: ethanol: ethylenediamine: acetic acid (800:200:0.5:0.5) (v/v/v/v) as the mobile phase in an isocratic elution. The eluents were monitored by UV/Visible detector at 290 nm. The resolution between S-isomer and besifloxacin hydrochloride was more than 2.0. Based on a signal-to-noise ratio of 3 and 10 the LOD of besifloxacin was 0.30 μg/mL, while the LOQ was 0.90 μg/mL. The calibration curves were linear in the range of 0.9-7.5 μg/mL. Precision of the method was established within the acceptable range. The method was suitable for the quality control enantiomeric impurity in besifloxacin hydrochloride. Chirality 28:628-632, 2016. © 2016 Wiley Periodicals, Inc. PMID:27563753

  18. Fractionating power and outlet stream polydispersity in asymmetrical flow field-flow fractionation. Part I: isocratic operation.

    PubMed

    Williams, P Stephen

    2016-05-01

    Asymmetrical flow field-flow fractionation (As-FlFFF) has become the most commonly used of the field-flow fractionation techniques. However, because of the interdependence of the channel flow and the cross flow through the accumulation wall, it is the most difficult of the techniques to optimize, particularly for programmed cross flow operation. For the analysis of polydisperse samples, the optimization should ideally be guided by the predicted fractionating power. Many experimentalists, however, neglect fractionating power and rely on light scattering detection simply to confirm apparent selectivity across the breadth of the eluted peak. The size information returned by the light scattering software is assumed to dispense with any reliance on theory to predict retention, and any departure of theoretical predictions from experimental observations is therefore considered of no importance. Separation depends on efficiency as well as selectivity, however, and efficiency can be a strong function of retention. The fractionation of a polydisperse sample by field-flow fractionation never provides a perfectly separated series of monodisperse fractions at the channel outlet. The outlet stream has some residual polydispersity, and it will be shown in this manuscript that the residual polydispersity is inversely related to the fractionating power. Due to the strong dependence of light scattering intensity and its angular distribution on the size of the scattering species, the outlet polydispersity must be minimized if reliable size data are to be obtained from the light scattering detector signal. It is shown that light scattering detection should be used with careful control of fractionating power to obtain optimized analysis of polydisperse samples. Part I is concerned with isocratic operation of As-FlFFF, and part II with programmed operation. Graphical abstract The dash-dotted blue curve describes an assumed log-normal sample molecular weight distribution (right axis

  19. Quest for organic polymer-based monolithic columns affording enhanced efficiency in high performance liquid chromatography separations of small molecules in isocratic mode

    PubMed Central

    Svec, Frantisek

    2011-01-01

    The separations of small molecules using columns containing porous polymer monoliths invented two decades ago went a long way from the very modest beginnings to the current capillary columns with efficiencies approaching those featured by their silica-based counterparts. This review article presents a variety of techniques that have been used to form capillary formats of monolithic columns with enhanced separation performance in isocratic elutions. The following text first describes the traditional approaches used for the preparation of efficient monoliths comprising variations in polymerization conditions including temperature as well as composition of monomers and porogenic solvents. Encouraging results of these experiments fueled research of completely new preparation methods such as polymerization to an incomplete conversion, use of single crosslinker, hypercrosslinking, and incorporation of carbon nanotubes that are described in the second part of the text. PMID:21816401

  20. Sequential elution process

    DOEpatents

    Kingsley, Ilse S.

    1987-01-01

    A process and apparatus for the separation of complex mixtures of carbonaceous material by sequential elution with successively stronger solvents. In the process, a column containing glass beads is maintained in a fluidized state by a rapidly flowing stream of a weak solvent, and the sample is injected into this flowing stream such that a portion of the sample is dissolved therein and the remainder of the sample is precipitated therein and collected as a uniform deposit on the glass beads. Successively stronger solvents are then passed through the column to sequentially elute less soluble materials.

  1. Sequential elution process

    DOEpatents

    Kingsley, I.S.

    1987-01-06

    A process and apparatus are disclosed for the separation of complex mixtures of carbonaceous material by sequential elution with successively stronger solvents. In the process, a column containing glass beads is maintained in a fluidized state by a rapidly flowing stream of a weak solvent, and the sample is injected into this flowing stream such that a portion of the sample is dissolved therein and the remainder of the sample is precipitated therein and collected as a uniform deposit on the glass beads. Successively stronger solvents are then passed through the column to sequentially elute less soluble materials. 1 fig.

  2. Innovative Elution Processes for Recovering Uranium from Seawater

    SciTech Connect

    Wai, Chien; Tian, Guoxin; Janke, Christopher

    2014-05-29

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium

  3. Drug-eluting medical implants.

    PubMed

    Zilberman, Meital; Kraitzer, Amir; Grinberg, Orly; Elsner, Jonathan J

    2010-01-01

    Drug-eluting medical implants are actually active implants that induce healing effects, in addition to their regular task of support. This effect is achieved by controlled release of active pharmaceutical ingredients (API) into the surrounding tissue. In this chapter we focus on three types of drug-eluting devices: drug-eluting vascular stents, drug-eluting wound dressings and protein-eluting scaffolds for tissue regeneration, thus describing both internal and external implants. Each of these drug-eluting devices also presents an approach for solving the drug release issue. Most drug-eluting vascular stents are loaded with water-insoluble antiproliferative agents, and their diffusion from the device to the surrounding tissue is relatively slow. In contrast, most drug-eluting wound dressings are loaded with highly water-soluble antibacterial agents and the issue of fast release must therefore be addressed. Growth factor release from scaffolds for tissue regeneration offers a new approach of incorporating high-molecular-weight bioactive agents which are very sensitive to process conditions and preserve their activity during the preparation stage. The drug-eluting medical implants are described here in terms of matrix formats and polymers, incorporated drugs and their release profiles from the implants, and implant functioning. Basic elements, such as new composite core/shell fibers and structured films, can be used to build new antibiotic-eluting devices. As presented in this chapter, the effect of the processing parameters on the microstructure and the resulting drug release profiles, mechanical and physical properties, and other relevant properties, must be elucidated in order to achieve the desired properties. Newly developed implants and novel modifications of previously developed approaches have enhanced the tools available for creating clinically important biomedical applications. PMID:20217535

  4. Expressions of the fundamental equation of gradient elution and a numerical solution of these equations under any gradient profile.

    PubMed

    Nikitas, P; Pappa-Louisi, A

    2005-09-01

    The original work carried out by Freiling and Drake in gradient liquid chromatography is rewritten in the current language of reversed-phase liquid chromatography. This allows for the rigorous derivation of the fundamental equation for gradient elution and the development of two alternative expressions of this equation, one of which is free from the constraint that the holdup time must be constant. In addition, the above derivation results in a very simple numerical solution of the various equations of gradient elution under any gradient profile. The theory was tested using eight catechol-related solutes in mobile phases modified with methanol, acetonitrile, or 2-propanol. It was found to be a satisfactory prediction of solute gradient retention behavior even if we used a simple linear description for the isocratic elution of these solutes. PMID:16131080

  5. Simultaneous quantification of flavonoids and phenolic acids in plant materials by a newly developed isocratic high-performance liquid chromatography approach.

    PubMed

    Haghi, Ghasem; Hatami, Alireza

    2010-10-27

    A simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method based on isocratic elution has been developed and validated for the simultaneous quantitation of flavonols (myricetin, quercetin, kaempferol, and isorhamnetin), flavones (luteolin and apigenin), and phenolic acids (chlorogenic, caffeic, ellagic, and rosmarinic acids) as important constituents in fruits, vegetables, and medicinal plants. Analysis was achieved on a C18 column at ambient temperature. The wavelengths used for the detection of flavonols, flavones, and phenolic acids were 370, 350, and 325 nm, respectively. After acid hydrolysis, the flavonoid aglycones were quantified straightforwardly in 20 dry herbal samples. The plants with the highest flavonoids were Rosa damascena, Solidago virgaurea, Ginkgo biloba, and Camellia sinensis. The contents of flavonoids aglycons ranged from 0.54 to 11.10 mg/g, from 0.03 to 14.80 mg/g, from 0.19 to 2.76 mg/g, from 0.15 to 2.36 mg/g, from 0.27 to 2.05 mg/g, and from 0.42 to 1.82 mg/g for quercetin, kaempferol, isorhamnetin, luteolin, apigenin, and myricetin in dry plant samples, respectively. PMID:20919719

  6. Rapid determination of vitamin B2 and B12 in human urine by isocratic liquid chromatography.

    PubMed

    Mandal, Santi M; Mandal, Mahitosh; Ghosh, Ananta K; Dey, Satyahari

    2009-04-27

    A simple and rapid method for the identification and quantification of vitamin B(2) and B(12) in human urine has been developed using reverse phase high performance liquid chromatography (HPLC) and the peaks identity were confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). HPLC separation was performed in single wavelength detector (lambda(365)) mode and separated isocratically using mobile phase methanol: 1mM aqueous TFA (1:4) in C18 column. The calibration graphs plotted with different concentrations of vitamin B(2) and B(12) was linear with a correlation coefficients (r(2))=0.9975 and 0.9985, respectively. The recoveries of vitamin B(2) and B(12) were above 87% and 90%, respectively. The results of this present study suggest that the proposed method may be simple and convenient way of identifying and quantifying vitamin B(2) and B(12) from human urine. PMID:19362629

  7. Elution profiles of lanthanides with α-hydroxyisobutyric acid by ion exchange chromatography using fine resin.

    PubMed

    Trikha, Rahul; Sharma, Bal Krishan; Sabharwal, Kanwal Nain; Prabhu, Krishan

    2015-11-01

    Experiments were carried out using a strong acid cation exchange resin with a particle size of 75-150 μm, termed as "fine resin" in hydrogen ion form for the elution of individual lanthanides Sm, Eu, Gd, Tb, and Dy that are produced as fission products in the spent nuclear fuel and generated in the effluent during reprocessing of spent nuclear fuel. Batch experiments were carried out to study the effect of concentration of nitric acid on distribution coefficient. The distribution coefficient values for these individual lanthanides were determined in nitric acid medium in the concentration range of 0.01-4.0 N. Uptake of each individual lanthanide by resin was increased with increased nitric acid concentration from 0.01 to 0.5 N and remained similar from 0.5 to 1.0 N and decreased thereafter up to 4.0 N. Column experiments were also carried out using the same resin to study the parameters like pH of the eluent, flow rate, and resin bed height under isocratic elution conditions for eluting lanthanide elements using α-hydroxyisobutyric acid as eluent. The results of this study have indicated the possibility for the elution of individual lanthanides. PMID:26333182

  8. ELUTION OF URANIUM FROM RESIN

    DOEpatents

    McLEan, D.C.

    1959-03-10

    A method is described for eluting uranium from anion exchange resins so as to decrease vanadium and iron contamination and permit recycle of the major portion of the eluats after recovery of the uranium. Diminution of vanadium and iron contamination of the major portion of the uranium is accomplished by treating the anion exchange resin, which is saturated with uranium complex by adsorption from a sulfuric acid leach liquor from an ore bearing uranium, vanadium and iron, with one column volume of eluant prepared by passing chlorine into ammonium hydroxide until the chloride content is about 1 N and the pH is about 1. The resin is then eluted with 8 to 9 column volumes of 0.9 N ammonium chloride--0.1 N hydrochloric acid solution. The eluants are collected separately and treated with ammonia to precipitate ammonium diuranate which is filtered therefrom. The uranium salt from the first eluant is contaminated with the major portion of ths vanadium and iron and is reworked, while the uranium recovered from the second eluant is relatively free of the undesirable vanadium and irons. The filtrate from the first eluant portion is discarded. The filtrate from the second eluant portion may be recycled after adding hydrochloric acid to increase the chloride ion concentration and adjust the pH to about 1.

  9. Optimization of IC Separation Based on Isocratic-to-Gradient Retention Modeling in Combination with Sequential Searching or Evolutionary Algorithm

    PubMed Central

    Rogošić, Marko; Šimović, Ena; Tišler, Vesna; Bolanča, Tomislav

    2013-01-01

    Gradient ion chromatography was used for the separation of eight sugars: arabitol, cellobiose, fructose, fucose, lactulose, melibiose, N-acetyl-D-glucosamine, and raffinose. The separation method was optimized using a combination of simplex or genetic algorithm with the isocratic-to-gradient retention modeling. Both the simplex and genetic algorithms provided well separated chromatograms in a similar analysis time. However, the simplex methodology showed severe drawbacks when dealing with local minima. Thus the genetic algorithm methodology proved as a method of choice for gradient optimization in this case. All the calculated/predicted chromatograms were compared with the real sample data, showing more than a satisfactory agreement. PMID:24349824

  10. Instrument parameters controlling retention precision in gradient elution reversed-phase liquid.

    PubMed

    Beyaza, Ayse; Fana, Wenzhe; Carr, Peter W; Schellinger, Adam P

    2014-12-01

    The precision of retention time in RPLC is important for compound identification, for setting peak integration time windows and in fundamental studies of retention. In this work, we studied the effect of temperature (T), initial (ϕo) and final mobile phase (ϕf) composition, gradient time (tG), and flow rate (F) on the retention time precision under gradient elution conditions for various types of low MW solutes. We determined the retention factor in pure water ( [Formula: see text] ) and the solute-dependent solvent strength (S) parameters of Snyder's linear solvent strength theory (LSST) as a function of temperature for three different groups of solutes. The effect of small changes in the chromatographic variables (T, ϕo, ϕf, tG and F) by use of the LSST gradient retention equation were estimated. Peaks at different positions in the chromatogram have different sensitivities to changes in these instrument parameters. In general, absolute fluctuations in retention time are larger at longer gradient times. Drugs showed less sensitivity to changes in temperature compared to relatively less polar solutes, non-ionogenic solutes. Surprisingly we observed that fluctuations in temperature, mobile phase composition and flow rate had less effect on retention time under gradient conditions as compared to isocratic conditions. Overall temperature and the initial mobile phase composition are the most important variables affecting retention reproducibility in gradient elution chromatography. PMID:25459648

  11. Effect of ionic additives on the elution of sodium aryl sulfonates in supercritical fluid chromatography.

    PubMed

    Zheng, J; Taylor, L T; Pinkston, J David; Mangels, M L

    2005-08-01

    Addition of a small amount of polar solvent (i.e., modifier) to CO2 in packed column supercritical fluid chromatography (SFC) has shown major improvements in both polar analyte solubility and interaction of the polar analyte with the stationary phase. Recently, the addition of an ionic component (i.e., additive) to the primary modifier by one of us has been shown to extend even further the application of SFC to polar analytes. In this work, the effect of various ionic additives on the elution of ionic compounds, such as sodium 4-dodecylbenzene sulfonate and sodium 4-octylbenene sulfonate, has been studied. The additives were lithium acetate, ammonium acetate, tetramethylammonium acetate, tetrabutylammonium acetate, and ammonium chloride dissolved in methanol. Three stationary phases with different degrees of deactivation were considered: conventional cyanopropyl, deltabond cyanopropyl, and bare silica. The effect of additive concentration and additive functionality on analyte retention was investigated. Sodium 4-dodecylbenzene sulfonate was successfully eluted using all the additives with good peak shape under isocratic/isobaric/isothermal conditions. Different additives, however, yielded different retention times and in some cases different peak shapes. PMID:16035365

  12. Instrument Parameters Controlling Retention Precision in Gradient Elution Reversed-Phase Liquid Chromatography

    PubMed Central

    Beyaz, Ayse; Fan, Wenzhe; Carr, Peter W.; Schellinger, Adam P.

    2014-01-01

    The precision of retention time in RPLC is important for compound identification, for setting peak integration time windows and in fundamental studies of retention. In this work, we studied the effect of temperature (T), initial (ϕ0) and final mobile phase (ϕf)composition, gradient time (tG), and flow rate (F) on the retention time precision under gradient elution conditions for various types of low MW solutes. We determined the retention factor in pure water (k′w) and the solute-dependent solvent strength (S) parameters of Snyder's linear solvent strength theory (LSST) as a function of temperature for three different groups of solutes. The effect of small changes in the chromatographic variables (T, ϕ0, ϕf, tG and F) by use of the LSST gradient retention equation were estimated. Peaks at different positions in the chromatogram have different sensitivities to changes in these instrument parameters. In general, absolute fluctuations in retention time are larger at longer gradient times. Drugs showed less sensitivity to changes in temperature compared to relatively less polar solutes, non-ionogenic solutes. Surprisingly we observed that fluctuations in temperature, mobile phase composition and flow rate had less effect on retention time under gradient conditions as compared to isocratic conditions. Overall temperature and the initial mobile phase composition are the more important variables affecting retention reproducibility in gradient elution chromatography. PMID:25459648

  13. Gradient elution in capillary electrochromatography

    SciTech Connect

    Anex, D.; Rakestraw, D.J.; Yan, Chao; Dadoo, R.; Zare, R.N.

    1997-08-01

    In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically-driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with sub-mL/min flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-mm reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled programmable high-voltage power supplies (0-50 kV)--one providing an increasing ramp and the other providing a decreasing ramp--are used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically-driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons (PAHs) was separated in less than 90 minutes. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC, but also other types of gradients such as pH- and ionic-strength gradients in capillary electrokinetic separations and analyses.

  14. An isocratic HPLC method for the determination of sorbitol and glycerol in pharmaceutical formulations.

    PubMed

    Simonzadeh, Ninus; Ronsen, Bruce

    2012-08-01

    Sorbitol and glycerol, along with other inactive ingredients such as preservatives and dyes, are commonly used in various pharmaceutical and personal care products. To accurately assess the effectiveness of various formulations containing sorbitol and/or glycerol, their quantitative determination is essential. In the current study, two types of detectors (a Varian evaporative light scattering detector and an Agilent ultraviolet-visible detector) are evaluated for the assay of working sample solutions. The two detection techniques are complimentary, and a comparison of the results obtained using the two detectors is presented here. The current method is shown to be stability-indicating and free from interference from any of the formulation excipients and potential degradation products. The method is reproducible, accurate, sensitive and selective. It provides enhanced detection sensitivity for sorbitol and comparable sensitivity for glycerol versus similar methods reported in the literature that utilize a refractive index detector for the analysis of either of the two polyols. PMID:22565491

  15. Evaluation of electrochemical ion exchange for cesium elution

    SciTech Connect

    Bontha, J.D.; Kurath, D.E.; Surma, J.E.; Buehler, M.F.

    1996-04-01

    Electrochemical elution was investigated as an alternative method to acid elution for the desorption of cesium from loaded ion exchange resins. The approach was found to have several potential advantages over existing technologies, in particular, electrochemical elution eliminates the need for addition of chemicals to elute cesium from the ion exchange resin. Also, since, in the electrochemical elution process the eluting solution is not in direct contact with the ion exchange material, very small volumes of the eluting solution can be used in a complete recycle mode in order to minimize the total volume of the cesium elute. In addition, the cesium is eluted as an alkaline solution that does not require neutralization with caustic to meet the tank farm specifications. Other advantages include easy incorporation of the electrochemical elution process into the present cesium recovery schemes.

  16. Paclitaxel-Eluting versus Everolimus-Eluting Coronary Stents in Diabetes.

    PubMed

    2016-07-28

    Paclitaxel-Eluting versus Everolimus-Eluting Coronary Stents in Diabetes Original Article, N Engl J Med 2015;373:1709-1719. In the list of authors (page 1709), the surname Abhaychand should have been Abhaichand. The article is correct at NEJM.org. PMID:27464221

  17. Fractionated elution using the TEKCIS technetium-99m generator.

    PubMed

    Vigne, Jonathan; De Mil, Rémy; Peyronnet, Damien; Hecquard, Claudine; Agostini, Denis; Lemonnier, Françoise

    2016-06-01

    The TEKCIS technetium-99m (Tc) generator was designed to allow dry column shipment and automatized conception. A high Tc radioactive concentration is required in a subset of radiopharmacy procedures. Fractionated elution can be a useful tool to meet this requirement, especially when current elution is close to the generator expiration date. The aim of our study was to assess TEKCIS generator elution kinetics and to determine the optimal fractionated elution time to fit with procedures requiring the highest Tc radioactive concentration in clinical use. After duplicate elution at several predetermined elution times, the volume and activity of each eluate were measured. Two optimal time points were selected to perform fractionated elution and repeatability (n=34 and 33) assessed on TEKCIS generators calibrated at 6 or 8 GBq. The complete eluate volume (5 ml) was collected after 60 s of elution. A logarithmic equation was established between eluate volume (v, ml) from elapsed elution time (t, s): v=1.8335ln(t)-2.5965. Using the reciprocal equation, elution times required to obtain some commonly eluted volumes were calculated. Fractionated elutions during 15 and 20 s were selected and an average elution volume from 2.74 to 3.27 ml was collected, with an average elution yield of approximately 90 and 100%, respectively. Our work provides a simple and reliable methodology for the use of fractionated elution with the new TEKCIS generator. PMID:26945284

  18. Highly porous drug-eluting structures

    PubMed Central

    Elsner, Jonathan J.; Kraitzer, Amir; Grinberg, Orly; Zilberman, Meital

    2012-01-01

    For many biomedical applications, there is need for porous implant materials. The current article focuses on a method for preparation of drug-eluting porous structures for various biomedical applications, based on freeze drying of inverted emulsions. This fabrication process enables the incorporation of any drug, to obtain an “active implant” that releases drugs to the surrounding tissue in a controlled desired manner. Examples for porous implants based on this technique are antibiotic-eluting mesh/matrix structures used for wound healing applications, antiproliferative drug-eluting composite fibers for stent applications and local cancer treatment, and protein-eluting films for tissue regeneration applications. In the current review we focus on these systems. We show that the release profiles of both types of drugs, water-soluble and water-insoluble, are affected by the emulsion's formulation parameters. The former's release profile is affected mainly through the emulsion stability and the resulting porous microstructure, whereas the latter's release mechanism occurs via water uptake and degradation of the host polymer. Hence, appropriate selection of the formulation parameters enables to obtain desired controllable release profile of any bioactive agent, water-soluble or water-insoluble, and also fit its physical properties to the application. PMID:23507890

  19. Cost-Effectiveness Analysis of Infrapopliteal Drug-Eluting Stents

    SciTech Connect

    Katsanos, Konstantinos Karnabatidis, Dimitris; Diamantopoulos, Athanasios; Spiliopoulos, Stavros; Siablis, Dimitris

    2013-02-15

    IntroductionThere are no cost-utility data about below-the-knee placement of drug-eluting stents. The authors determined the cost-effectiveness of infrapopliteal drug-eluting stents for critical limb ischemia (CLI) treatment. The event-free individual survival outcomes defined by the absence of any major events, including death, major amputation, and target limb repeat procedures, were reconstructed on the basis of two published infrapopliteal series. The first included spot Bail-out use of Sirolimus-eluting stents versus bare metal stents after suboptimal balloon angioplasty (Bail-out SES).The second was full-lesion Primary Everolimus-eluting stenting versus plain balloon angioplasty and bail-out bare metal stenting as necessary (primary EES). The number-needed-to-treat (NNT) to avoid one major event and incremental cost-effectiveness ratios (ICERs) were calculated for a 3-year postprocedural period for both strategies. Overall event-free survival was significantly improved in both strategies (hazard ratio (HR) [confidence interval (CI)]: 0.68 [0.41-1.12] in Bail-out SES and HR [CI]: 0.53 [0.29-0.99] in Primary EES). Event-free survival gain per patient was 0.89 (range, 0.11-3.0) years in Bail-out SES with an NNT of 4.6 (CI: 2.5-25.6) and a corresponding ICER of 6,518 Euro-Sign (range 1,685-10,112 Euro-Sign ). Survival gain was 0.91 (range 0.25-3.0) years in Primary EES with an NNT of 2.7 (CI: 1.7-5.8) and an ICER of 11,581 Euro-Sign (range, 4,945-21,428 Euro-Sign ) per event-free life-year gained. Two-way sensitivity analysis showed that stented lesion length >10 cm and/or DES list price >1000 Euro-Sign were associated with the least economically favorable scenario in both strategies. Both strategies of bail-out SES and primary EES placement in the infrapopliteal arteries for CLI treatment exhibit single-digit NNT and relatively low corresponding ICERs.

  20. Coronary vasomotion dysfunction after everolimus-eluting stent implantation.

    PubMed

    Giudice, Pietro; Attisano, Tiziana; Di Maio, Marco; Bellino, Elisabetta M; Polito, Maria V; Baldi, Cesare; Vigorito, Francesco; Di Muro, Michele R; Tomasello, Salvatore D; Galassi, Alfredo R; Piscione, Federico

    2014-12-01

    First generation drug-eluting stent can cause a paradoxical "in-segment" coronary vasoconstriction. This phenomenon was seen with sirolimus, paclitaxel, and, more recently, also with zotarolimus-eluting stent. For the first time, we describe a case of coronary-induced vasoconstriction by everolimus-eluting stents (EES). PMID:25598992

  1. ELUTION OF URANIUM VALUES FROM ION EXCHANGE RESINS

    DOEpatents

    Kennedy, R.H.

    1959-11-24

    A process is described for eluting complex uranium ions absorbed on ion exchange resins. The resin is subjected to the action of an aqueous eluting solution contuining sulfuric acid and an alkali metal, ammonium, or magnesium chloride or nitrate, the elution being carried out until the desired amount of the uranium is removed from the resin.

  2. Recent Advances in Drug Eluting Stents

    PubMed Central

    Puranik, Amey S.; Dawson, Eileen R.; Peppas, Nicholas A.

    2013-01-01

    One of the most common medical interventions to reopen an occluded vessel is the implantation of a coronary stent. While this method of treatment is effective initially, restenosis, or the re-narrowing of the artery frequently occurs largely due to neointimal hyperplasia of smooth muscle cells. Drug eluting stents were developed in order to provide local, site-specific, controlled release of drugs that can inhibit neointima formation. By implementing a controlled release delivery system it may be possible to control the time release of the pharmacological factors and thus be able to bypass some of the critical events associated with stent hyperplasia and prevent the need for subsequent intervention. However, since the advent of first-generation drug eluting stents, long-term adverse effects have raised concerns regarding their safety. These limitations in safety and efficacy have triggered considerable research in developing biodegradable stents and more potent drug delivery systems. In this review, we shed light on the current state-of-the-art in drug eluting stents, problems related to them and highlight some of the ongoing research in this area. PMID:23117022

  3. The Supralimus sirolimus-eluting stent.

    PubMed

    Lemos, Pedro A; Bienert, Igor

    2013-05-01

    The use of biodegradable polymeric coatings has emerged as a potential bioengineering target to improve the vascular compatibility of coronary drug-eluting stents (DESs). This review summarizes the main features and scientific facts about the Supralimus sirolimus-eluting stent (Sahajanand Medical Technologies Ltd, Surat, India), which is a biodegradable polymer-based, sirolimus-eluting metallic stent that was recently introduced for routine use in Europe. The novel stent is built on a stainless steel platform, coated with a blend of biodegradable polymers (poly-l-lactide, poly-dl-lactide-co-glycolide and polyvinyl pyrrolidone; coating thickness is 4-5 µm). The active agent is the antiproliferative sirolimus in a dose load of 1.4 µg/mm(2), which is released within 48 days. The Supralimus stent was initially evaluated in the single-arm SERIES-I study, which showed binary angiographic restenosis rates of 0% (in-stent) and 1.7% (in-segment) and an in-stent late lumen loss of 0.09 ± 0.28 mm. The multicenter randomized PAINT trial compared two DESs with identical metallic platforms and biodegradable polymer carriers, but different agents (Infinnium [Sahajanand Medical Technologies Pvt Ltd] paclitaxel-eluting stent or Supralimus sirolimus-eluting stent) against bare stents. After 3 years, the pooled DES population had similar rates of cardiac death or myocardial infarction (9 vs 7.1%; p = 0.6), but a lower risk of repeat interventions (10 vs 29.9%; p < 0.01) than controls with bare stents. The incidence of definite or probable stent thrombosis in the pooled DES group was 2.3% (1st year: 1.8%; 2nd year: 0.4% and 3rd year: 0%). These results demonstrate that the novel Supralimus stents are effective in reducing reintervention, while potentially improving the safety profile by decreasing the risk of late-term thrombosis, even though further studies would be necessary to confirm these findings. PMID:23597097

  4. [Drug-eluting stents: long-term safety].

    PubMed

    Karpov, Iu A; Samko, A N; Buza, V V

    2009-01-01

    The review concerns the problem of late thromboses of drug-eluting stents and their influence on late prognosis of the patients; presents long-term results of the trial of sirolimus-eluting stents implanted to patients with coronary heart disease; analyses mechanisms of development of late stent thrombosis, data from different meta-analyses and registers comparing long-term outcomes in patients with implanted sirolimus-eluting stents and metallic stents; suggests risk factors of late thromboses of drug-eluting stents; presents original evidence on 3.5-year follow-up of patients with implanted sirolimus-eluting stents and metallic stents. PMID:19537584

  5. Prediction of Neutral Salt Elution Profiles for Affinity Chromatography

    NASA Astrophysics Data System (ADS)

    Robinson, Jack B.; Strottmann, James M.; Stellwagen, Earle

    1981-04-01

    Neutral salts exhibit very marked differences as eluants of proteins from affinity columns. We observe: (i) that the relative potencies of neutral salts as eluants are independent of the protein or the affinity ligand in the systems studied, (ii) that the absolute salt concentration necessary to elute any given protein bound to the affinity matrix is proportional to the algebraic sum of a set of elution coefficients defined herein for the separate ions present in the solution, and (iii) that the proportionality between elution potency and elution coefficient is a function of the affinity of the protein for the immobilized ligand. Given the concentration of one neutral salt required for elution of a protein of interest from an affinity column, the elution capability of any neutral salt at any temperature can be quantitatively predicted for that protein. Accordingly, application and elution protocols for affinity chromatography can be designed to optimize the yield and fold purification of proteins.

  6. Second generation drug-eluting stents: a review of the everolimus-eluting platform.

    PubMed

    Whitbeck, Matthew G; Applegate, Robert J

    2013-01-01

    Everolimus-eluting stents (EES) represent the next generation of drug-eluting stents (DES). Important design modifications include thin strut stent backbones, less inflammatory and more biocompatible polymers, and lower drug dosing. The cobalt chromium EES fluoropolymer XIENCE V stent has been the most extensively studied of such stents. In animal models, this stent demonstrated minimal vessel inflammation, a biologically active endothelium with strut coverage similar to a bare metal stent, and inhibition of intimal hyperplasia comparable to that seen with sirolimus-eluting stents. The SPIRIT family of clinical trials demonstrated low rates of late loss, and clinical restenosis, as well as low rates of very late stent thrombosis. These excellent clinical outcomes addressed limitations of the 1st generation DES, and substantiated widespread clinical use of the EES platform. PMID:23926441

  7. Modelling Simple Experimental Platform for In Vitro Study of Drug Elution from Drug Eluting Stents (DES)

    NASA Astrophysics Data System (ADS)

    Kalachev, L. V.

    2016-06-01

    We present a simple model of experimental setup for in vitro study of drug release from drug eluting stents and drug propagation in artificial tissue samples representing blood vessels. The model is further reduced using the assumption on vastly different characteristic diffusion times in the stent coating and in the artificial tissue. The model is used to derive a relationship between the times at which the measurements have to be taken for two experimental platforms, with corresponding artificial tissue samples made of different materials with different drug diffusion coefficients, to properly compare the drug release characteristics of drug eluting stents.

  8. The future of drug eluting stents

    PubMed Central

    Anis, R R; Karsch, K R

    2006-01-01

    In‐stent restenosis (ISR) is the major drawback of percutaneous coronary interventions, occurring in 10–40% of patients. Drug eluting stents (DES) are successful in a large majority of patients in preventing restenosis for the first year after implantation. Recently, new stents have emerged that are loaded with anti‐inflammatory, antimigratory, antiproliferative, or pro‐healing drugs. These drugs are supposed to inhibit inflammation and neointimal growth and subsequently ISR. The future of DES lies in the development of better stents with new stent designs, better polymers including biological polymers and biological biodissolvable stent coatings, and new, better drugs. PMID:16216857

  9. Mixed-mode ion-exchangers and their comparative chromatographic characterization in reversed-phase and hydrophilic interaction chromatography elution modes.

    PubMed

    Lämmerhofer, Michael; Richter, Martin; Wu, Junyan; Nogueira, Raquel; Bicker, Wolfgang; Lindner, Wolfgang

    2008-08-01

    A set of particulate silica-supported mixed-mode RP/weak anion-exchangers (RP/WAX) (obtained by bonding of N-undecenoylated 3-aminoquinuclidine, 3-aminotropane and 2-dimethylaminoethylamine as well as of N-butenoyl-(2S,4S,5R)-2-aminomethyl-5-[(2-octylthio)ethyl]-quinuclidine to thiol-modified silica) were chromatographically characterized in comparison to selected commercially available columns using two distinct isocratic elution modes, viz. an aqueous-rich RP-type elution mode (with 40% ACN and 60% buffer) as well as an organic solvent-rich hydrophilic interaction chromatography (HILIC)-type elution mode (95 and 90% ACN). The mixed-mode RP/WAX phases showed multimodal applicability, unlike a polar embedded RP material (Synergi Fusion RP), amino phases (Luna NH(2), BioBasic AX) or typical HILIC packings (ZIC-HILIC, TSKGel Amide-80). Principal component analysis (PCA) of the RP test data confirmed that the in-house developed RP/WAX columns as well as the Acclaim Mixed-Mode WAX-1 phase resemble each other in their chromatographic characteristics having slightly lower hydrophobic selectivity (alpha(CH2) of 1.5) than the tested Synergi Fusion RP (alpha(CH2) approximately 1.8). In contrast, a decrease in mixed-mode character due to lowered ion-exchange capacity and concomitantly increased RP-like behavior could be identified for other mixed-mode phases in the order of Obelisc R > Primesep B2 > Uptisphere MM3. PCA on HILIC data revealed that the RP/WAX phases behave dissimilar to TSKGel Amide-80, ZIC-HILIC and polysulfoethyl A under the chosen elution conditions. Hence, they may be regarded as complementary to these commercial stationary phases with applicability profiles for hydrophilic but also hydrophobic solutes. PMID:18693304

  10. Evaluation of Elution Parameters for Cesium Ion Exchange Resins

    SciTech Connect

    Burgeson, Ingrid E.; Deschane, Jaquetta R.; Cook, Bryan J.; Blanchard, David L.; Weier, Dennis R.

    2006-08-28

    Cesium ion exchange is one of the planned processes for treating and disposing of waste at the U.S. Department of Energy Hanford Site. Radioactive supernatant liquids from the waste tanks will undergo ultrafiltration, followed by cesium ion exchange using a regenerable organic ion exchange resin. Two resins, SuperLig?644 and a Resorcinol-formaldehyde resin are being evaluated for cesium removal and cesium elution characteristics. The main purpose of this study is to optimize the cesium elution to provide a resin which after undergoing elution would meet the U.S. Department of Energy/Office of River Protection Project-Waste Treatment Plant processing and resin disposal criteria. Columns of each resin type were loaded to greater or equal to 90% breakthrough with a Hanford waste stimulant and eluted with nitric acid. The temperature, flow rate and nitric acid concentration were varied to determine the optimal elution conditions. Temperature and eluant flow rate were the most important elution parameters. As would be predicted based upon kinetic consideration alone, decreasing the eluant flow rate and increasing the temperature provided the optimal elution conditions. Varying the nitric acid concentration did not have a significant effect on the elution; however, elutions performed using both high acid concentration (1M) and elevated temperature (45 C) resulted in resin degradation, causing gas generation and resin bed disruption.

  11. Determination of six kavalactones in dietary supplements and selected functional foods containing Piper methysticum by isocratic liquid chromatography with internal standard.

    PubMed

    Hu, Lihong; Jhoo, Jin-Woo; Ang, Catharina Y W; Dinovi, Michael; Mattia, Antonia

    2005-01-01

    Kava (Piper methysticum) dietary products have been sold worldwide for treatment of nervous anxiety, tension, and restlessness. Recent reports showed potential association of kava usage and liver injuries. This study was conducted to develop simple and reliable methodologies for the extraction and determination of 6 major kavalactones: (+)-methysticin, (+)-dihydromethysticin, (+)-kavain, (+)-dihydrokavain, yangonin, and desmethoxyyangonin. Ultrasonic extraction techniques and isocratic reversed-phase liquid chromatography (LC) were optimized for different types of samples, including capsules containing kava root extract or root powder, raw root material, tea bags, and snack bar. A suitable internal standard, 5,7-dihydroxyflavone, was used for LC calibration. Kavalactones were completely separated in 30 min using a Luna C18-2 column at 60 degrees C with an isocratic mobile phase consisting of 2-propanol-acetonitrile-water-acetic acid (16 + 16 + 68 + 0.1, v/v/v/v). Within-laboratory, intraday, and interday method variation (% relative standard deviation) for most samples extracted by methanol or methanol-water mixture were <5%. Lower levels of kavalactone contents and higher variations were observed for tea bags from water extraction or infusion as compared to methanol extraction. Labeling information of tea bags based on methanol extraction could be misleading to consumers. Analytical recoveries of snack bar fortified at 10 and 20 microg/g were >84% with RSD values <8%. Methods developed in this study offer a simple and reproducible means for analysis of kavalactones in various matrixes of dietary products. PMID:15759721

  12. Elution-Extrusion Countercurrent Chromatography: Theory and Concepts in Metabolic Analysis

    PubMed Central

    Berthod, Alain; Friesen, J. Brent; Inui, Taichi; Pauli, Guido F.

    2008-01-01

    Elution-extrusion countercurrent chromatography (EECCC) takes full advantage of the liquid nature of the stationary phase in CCC by combining regular chromatographic elution with stationary phase extrusion. EECCC is shown to be a three-stage process consisting of classical elution (I), sweeping elution (II), and extrusion (III). After only two column volumes of solvent, it rapidly yields a high-resolution chromatogram that covers an extended polarity range of solutes. As hydrophilicity/lipophilicity balance is a crucial discriminatory property of analytes in highly complex mixtures such as metabolomic samples, the precise determination of CCC distribution constants (KD) is vital to the analysis of metabolomes and other complex biological matrices. This work builds the EECCC concept by performing a full theoretical treatment and providing equations for retention volumes, peak widths, resolution factors, and distribution constants. Experimental validation utilizes natural products standards that resemble the zero to infinity range of the polarity continuum. EECCC extends the “sweet spot” of high-resolution in CCC, and provides access to the otherwise practically unapproachable high-KD portion of the high-resolution chromatograms in CCC. Its improved capabilities of KD-targeting make EECCC a promising tool for the specific analysis of “small” molecules in complex samples such as in metabolomic fingerprinting and footprinting. PMID:17408244

  13. [Recent developments of drug eluting stent coatings].

    PubMed

    Chen, Wen-ping; Zhan, Hong-bing

    2011-11-01

    Drug eluting stents (DESs) have revolutionized the interventional cardiology over the past decade since the first DES became commercially available in Europe in 2002. Compared to bare metal stents that are deployed to keep the vessel open by mechanical force, DESs have an additional function of reducing restenosis by the action of the drug on the target site. Coatings on the stent surface which ensure the maximum delivery of therapeutic agents to the target site with minimal systematic toxicity, also play an important role in adjusting the drug release profile. Coating material and technology not only affect the surface biocompatibility and the integrity maintenance during the implanting process, but also decide the way of drug delivering and transmitting from the coating. This paper reviews the basic principles of DES coating design, the categories of DES coatings, the commonly used clinical DES coatings and their efficiency in reducing restenosis, and finally provides the future perspectives for DES coatings. PMID:22260019

  14. Native Elution of Yeast Protein Complexes Obtained by Affinity Capture.

    PubMed

    LaCava, John; Fernandez-Martinez, Javier; Rout, Michael P

    2016-01-01

    This protocol describes two options for the native (nondenaturing) elution of protein complexes obtained by affinity capture. The first approach involves the elution of complexes purified through a tag that includes a human rhinovirus 3C protease (PreScission protease) cleavage site sequence between the protein of interest and the tag. Incubation with the protease cleaves immobilized complexes from the affinity medium. The second approach involves the release of protein A-tagged protein complexes using a competitive elution reagent called PEGylOx. The degree of purity of the native assemblies eluted is sample dependent and strongly influenced by the affinity capture. It should be noted that the efficiency of native elution is commonly lower than that of elution by a denaturing agent (e.g., SDS) and the release of the complex will be limited by the activity of the protease or the inhibition constant (Ki) of the competitive release agent. However, an advantage of native release is that some nonspecifically bound materials tend to stay adsorbed to the affinity medium, providing an eluted fraction of higher purity. Finally, keep in mind that the presence of the protease or elution peptide could potentially affect downstream applications; thus, their removal should be considered. PMID:27371597

  15. Simultaneous determination of eight biologically active thiol compounds using gradient elution-liquid chromatography with Coul-Array detection.

    PubMed

    Petrlova, Jitka; Mikelova, Radka; Stejskal, Karel; Kleckerova, Andrea; Zitka, Ondrej; Petrek, Jiri; Havel, Ladislav; Zehnalek, Josef; Vojtech, Adam; Trnkova, Libuse; Kizek, Rene

    2006-05-01

    The most active form of sulfur in biomolecules is the thiol group, present in a number of biologically active compounds. Here we present a comprehensive study of thiol analysis using flow injection analysis/HPLC with electrochemical detection. The effect of different potentials of working electrodes, of organic solvent contents in the mobile phase, and of isocratic and gradient elution on simultaneous determination of thiol compounds (cysteine, cystine, N-acetylcysteine, homocysteine, reduced and oxidised glutathione, desglycinephytochelatin, and phytochelatins) are described and discussed. These thiol compounds were well separated and detected under optimised HPLC-electrochemical detection conditions (mobile phase: 80 mM trifluoroacetic acid and methanol with a gradient profile starting at 97:3 (TFA:methanol), kept constant for the first 8 min, then decreasing to 85:15 during one minute, kept constant for 8 min, and finally increasing linearly up to 97:3 from 17 to 18 min; the flow rate was 0.8 mL/min, column and detector temperature 25 degrees C, and the electrode potential 900 mV). We were able to determine tens of femtomoles (3 S/N) of the thiols per injection (5 microL), except for phytochelatin5 whose detection limit was 2.1 pmole. This technique was consequently used for simultaneous determination of compounds of interest in biological samples (maize tissue and human blood serum). PMID:16830732

  16. Array tomography: immunostaining and antibody elution.

    PubMed

    Micheva, Kristina D; O'Rourke, Nancy; Busse, Brad; Smith, Stephen J

    2010-11-01

    Array tomography is a volumetric microscopy method based on physical serial sectioning. Ultrathin sections of a plastic-embedded tissue are cut using an ultramicrotome, bonded in an ordered array to a glass coverslip, stained as desired, and imaged. The resulting two-dimensional image tiles can then be reconstructed computationally into three-dimensional volume images for visualization and quantitative analysis. The minimal thickness of individual sections permits high-quality rapid staining and imaging, whereas the array format allows reliable and convenient section handling, staining, and automated imaging. Also, the physical stability of the arrays permits images to be acquired and registered from repeated cycles of staining, imaging, and stain elution, as well as from imaging using multiple modalities (e.g., fluorescence and electron microscopy). Array tomography makes it possible to visualize and quantify previously inaccessible features of tissue structure and molecular architecture. However, careful preparation of the tissue is essential for successful array tomography; these steps can be time-consuming and require some practice to perfect. In this protocol, tissue arrays are prepared for imaging by tagging with primary antibodies against specific cellular targets, followed by labeling with fluorescent secondary antibodies. Alternatively, fluorescent proteins that have been introduced into the tissue before dissection can be used. PMID:21041398

  17. Purification of the seven tetranortriterpenoids in neem (Azadirachta indica) seed by counter-current chromatography sequentially followed by isocratic preparative reversed-phase high-performance liquid chromatography.

    PubMed

    Silva, Júlio César T; Jham, Gulab N; Oliveira, Rosângela D'arc L; Brown, Leslie

    2007-06-01

    Counter-current chromatography (CCC) sequentially followed by isocratic preparative reversed-phase high-performance liquid chromatography was used to isolate the seven bio-actives (azadirachtin A, azadirachtin B, azadirachtin H, desacetylnimbin, desacetylsalannin, nimbin and salannin) from the seed concentrate (NSC) of the neem tree (Azadirachta indica A. Juss). Reproducible, narrow polarity range, high purity fractions were obtained from repeated injections of the NSC (700 mg loadings/injection), on to a relatively small volume CCC coil (116 mL). The CCC biphasic solvent system chosen was hexane:butanol:methanol:water (1:0.9:1:0.9, v/v). A mass balance of injected material showed that 95+% were recovered. PMID:17428489

  18. [Elution of urinary proteins preserved on nitrocellulose membrane with heating].

    PubMed

    Qin, Weiwei; Gao, Youhe

    2015-09-01

    The preservation of urinary proteins on a membrane plays a vital role in biomarker research, and the efficient elution of proteins preserved on nitrocellulose membrane (NC membrane) determines the application of this method. During the heating elution procedure, we raised the temperature to reduce the intense vortexing time, and kept gentle rotating while precipitation to prevent nitrocellulose reformation. We also used SDS-PAGE and LC-MS/MS to analyze the urinary proteins prepared by heating elution procedure, intense vortexing elution procedure and acetone precipitation method. There was no degradation of proteins prepared by heating elution procedure. Compared with proteins prepared by heating elution method and acetone precipitation method, the overlapping rates of the proteins was almost the same (92.6% versus 96.8%) and the ratios of CV values (< 20%) of the proteins were both high (85.2% and 94.4%). The heating elution procedure achieved good technical reproducibility, and was much simpler and more efficient than the previous one. It can facilitate the application of the preservation of urinary proteins on membrane. PMID:26955716

  19. Comparisons of Aluminum and Silica Elution from Various Glass Vials.

    PubMed

    Ogawa, Toru; Miyajima, Makoto; Nishimoto, Norihiro; Minami, Hidemi; Terada, Katsuhide

    2016-01-01

    To understand the risk of particle formation in glass vials, we investigated the correlation between vial surface condition and alminum (Al) or silicon (Si) elution using various suppliers' vials with or without surface treatment. The elution of Si, which can also be an indicator of Al elution, consists of two phases; the first phase is influenced by roughness of the glass surface at the time of filling, and the second phase is dependent on the fundamental elution rate from the glass tube. When vials were filled with citrate buffer at pH 7, vials with varied surface conditions showed the most obvious differences in Al and Si elution. Sulfur-treated vials showed slightly lower Al and Si elution than the non-treated vials. It is considered that this effect of the sulfur treatment on elution is due to the surface being smoothed during heat treatment after the washing process. Different from the sulfur treatment, silicon dioxide (SiO2)-coated vials hardly showed any Al elution as long as the surface was fully coated with the SiO2 layer. It was found that the protective effect of the SiO2 layer against Al elution is more effective in a vial filled with a solution having a lower pH, due to the lower Si dissolving rate occurring at a lower pH. As shown above, pre-measuring the Si and Al present in a citrate buffer at pH 7 placed within a glass container can be a useful tool for selecting the appropriate container for liquid drugs. PMID:26656229

  20. Elution of Ti during solvent extraction of coal and the transformation of eluted Ti upon combustion

    SciTech Connect

    Zhang, L.A.; Takanohashi, T.; Saito, I.; Wang, Q.Y.; Ninomiya, Y.

    2008-06-15

    Solvent extraction of coal is an effective method for removing coal ash, thereby generating the ultraclean fuel that can be directly combusted in gas turbine. Due to their organic affinity, a few inorganic elements can be extracted as well. Ti in coal extract, its elution from raw coal as well as the transformation of eluted Ti during coal extract combustion, have been investigated. Two coals of the U.S. and their acid-washed samples were extracted under 1 MPa N{sub 2} (cold) at 360{sup o}C. The solvents used include nonpolar 1-methylnaphthalene and its mixtures with polar indole. The results indicate that, Ti in coal extracts is mainly composed of nanoparticles including TiO{sub 2} (anatase) and Ti associated with quartz. These particles are insoluble in any acids, having a fine dispersion into coal matrix. Upon coal fragmentation at 360{sup o}C, they could be liberated, and, hence, traversed the filter for isolating coal extracts. The organo-Ti was preferentially extracted as well, which is most likely in a form of Ti porphyrin or Ti chelated with phenol-oxygen. These findings also have implications for revealing the modes of occurrence of Ti in the raw coals. Combustion of coal extract at 1,000{sup o}C resulted in the formation of nanometric TiO{sub 2} polymorphs and complex compounds like FeZnTiO{sub 4}. The former species could be mainly formed by the phase change of TiO{sub 2} (anatase) at high-temperatures, while formation of the latter one could involve the capture of metallic vapors like Zn on TiO{sub 2} polymorphs.

  1. Comparison of everolimus-eluting and biolimus-eluting coronary stents with everolimus-eluting bioresorbable scaffold: study protocol of the randomized controlled EVERBIO II trial

    PubMed Central

    2014-01-01

    Background Second-generation everolimus-eluting stents (EES) and third generation biolimus-eluting stents (BES) have been shown to be superior to first-generation paclitaxel-eluting stents (PES) and second-generation sirolimus-eluting stents (SES). However, neointimal proliferation and very late stent thrombosis is still an unresolved issue of drug-eluting stent (DES) implantation overall. The Absorb™ (Abbott Vascular, Abbott Park, IL, USA) is the first CE approved DES with a bioresorbable vascular scaffold (BVS) thought to reduce long-term complication rates. The EVERBIO II trial was set up to compare the BVS safety and efficacy with both EES and BES in all patients viable for inclusion. Methods/Design The EVERBIO II trial is a single-center, assessor-blinded, randomized trial. The study population consists of all patients aged ≥18 years old undergoing percutaneous coronary intervention. Exclusion criterion is where the lesion cannot be treated with BVS (reference vessel diameter >4.0 mm). A total of 240 patients will be enrolled and randomly assigned into 3 groups of 80 with either BVS, EES or BES implantation. All patients will undergo a follow-up angiography study at 9 months. Clinical follow-up for up to 5 years will be conducted by telephone. The primary endpoint is in-segment late lumen loss at 9 months measured by quantitative coronary angiography. Secondary endpoints are patient-oriented major adverse cardiac event (MACE) (death, myocardial infarction and target-vessel revascularization), device-oriented MACE (cardiac death, myocardial infarction and target-lesion revascularization), stent thrombosis according to ARC and binary restenosis at follow-up 12 months angiography. Discussion EVERBIO II is an independent, randomized study, aiming to compare the clinical efficacy, angiographic outcomes and safety of BVS, EES and BES in all comer patients. Trial registration The trial listed in clinicaltrials.gov as NCT01711931. PMID:24398143

  2. Liquid chromatography at critical conditions in ternary mobile phases: gradient elution along the critical line.

    PubMed

    Trathnigg, Bernd; Malik, Muhammad Imran; Pircher, Nicole; Hayden, Stephan

    2010-07-01

    In ternary mobile phases consisting of acetone, methanol, and water, the retention of PEG on reversed-phase columns is independent on molar mass at certain compositions of the mobile phase. Along this critical adsorption line, the retention of polypropylene glycol varies quite strongly, which can be utilized in the separation of block copolymers. Gradient elution along the critical line allows a baseline separation of all oligomers in polypropylene glycol up to approximately 25 propylene oxide units. The same resolution can be achieved in the separation of ethylene oxide-propylene oxide block copolymers, regardless of the length of the ethylene oxide block. PMID:20535754

  3. The simultaneous determination of active ingredients in cough-cold mixtures by isocratic reversed-phase ion-pair high-performance liquid chromatography.

    PubMed

    Lau, O W; Chan, K; Lau, Y K; Wong, W C

    1989-01-01

    A simple, rapid and accurate method for the simultaneous determination of active ingredients in cough-cold mixtures using isocratic reversed-phase ion-pair high-performance liquid chromatography has been developed. It involves the use of an octadecylsilane column as the stationary phase with methanol, water, tetrahydrofuran, phosphoric acid mixtures as mobile phase including sodium dioctylsulphosuccinate as the ion-pair agent. The pH of the mobile phase was adjusted to 4.6 by means of phosphoric acid and ammonium hydroxide solutions. The proposed method involves the simple dilution of the samples with the mobile phase and the addition of metoclopramide hydrochloride as the internal standard. The active ingredients under investigation were chlorpheniramine, codeine, diphenhydramine, ephedrine, ethylmorphine, phenylephrine, phenylpropanolamine and pholcodine, which exist as various combinations in cough-cold mixtures. The optimum composition of the mobile phase and the optimum flow rate were determined and are reported. The method was applied to the determination of active ingredients in seven commercially available cough-cold mixtures. PMID:2577452

  4. Fluid mechanics of DNA double-strand filter elution.

    PubMed Central

    Rudinger, George; Blazek, Ed Robert

    2002-01-01

    Measurement of infrequent DNA double-strand breaks (DSB) in mammalian cells is essential for the understanding of cell damage by ionizing radiation and many DNA-reactive drugs. One of the most important assays for measuring DSB in cellular DNA is filter elution. This study is an attempt to determine whether standard concepts of fluid mechanics can yield a self-consistent model of this process. Major assumptions of the analysis are reptation through a channel formed by surrounding strands, with only strand ends captured by filter pores. Both viscosity and entanglement with surrounding strands are considered to determine the resistance to this motion. One important result is that the average elution time of a strand depends not only on its length, but also on the size distribution of the surrounding strands. This model is consistent with experimental observations, such as the dependence of elution kinetics upon radiation dose, but independence from the size of the DNA sample up to a critical filter loading, and possible overlap of elution times for strands of different length. It indicates how the dependence of elution time on the flow rate could reveal the relative importance of viscous and entanglement resistance, and also predicts the consequences of using different filters. PMID:11751292

  5. Enhancement of diabetic wound repair using biodegradable nanofibrous metformin-eluting membranes: in vitro and in vivo.

    PubMed

    Lee, Cheng-Hung; Hsieh, Ming-Jer; Chang, Shang-Hung; Lin, Yu-Huang; Liu, Shih-Jung; Lin, Tzu-Yu; Hung, Kuo-Chun; Pang, Jong-Hwei S; Juang, Jyuhn-Huarng

    2014-03-26

    This work developed biodegradable nanofibrous drug-eluting membranes that provided sustained release of metformin for repairing wounds associated with diabetes. To prepare the biodegradable membranes, poly-d-l-lactide-glycolide (PLGA) and metformin were first dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and were spun into nanofibrous membranes by electrospinning. An elution method and an HPLC assay were utilized to characterize the in vivo and in vitro release rates of the pharmaceuticals from the membranes. The biodegradable nanofibrous membranes released high concentrations of metformin for more than three weeks. Moreover, nanofibrous metformin-eluting PLGA membranes were more hydrophilic and had a greater water-containing capacity than virgin PLGA fibers. The membranes also improved wound healing and re-epithelialization in diabetic rats relative to the control. The experimental results in this work suggest that nanofibrous metformin-eluting membranes were functionally active in the treatment of diabetic wounds and very effective as accelerators in the early stage of healing of such wounds. PMID:24568239

  6. Coronary vasomotion one year after drug-eluting stent implantation: comparison of everolimus-eluting and paclitaxel-eluting coronary stents.

    PubMed

    Hamilos, Michalis; Ribichini, Flavio; Ostojic, Miodrag C; Ferrero, Valeria; Orlic, Dejan; Vassanelli, Corrado; Karanovic, Nevena; Sarno, Giovanna; Cuisset, Thomas; Vardas, Panos E; Wijns, William

    2014-06-01

    First-generation drug-eluting stents (DES) have been associated with impaired localized coronary vasomotion and delayed endothelialization. We aimed to compare coronary vasomotion after implantation of a newer-generation everolimus-eluting stent (EES), with a first-generation paclitaxel-eluting stent (PES). Coronary vasomotion was studied in 19 patients with EES and 13 with PES. Vasomotor response was measured proximally and distally to the stent and in a remote vessel (reference segment). Quantitative coronary angiography was performed offline. Endothelium independent vasomotion did not differ significantly between the two groups. EES showed significant vasodilatation while PES showed vasoconstriction at both proximal (+4.5 ± 3.6 vs -4.2 ± 6.9, p < 0.001) and distal (+4.6 ± 7.9 vs -4.8 ± 9.3, p = 0.003) segments. The reference segment did not show any significant difference in vasodilatation between the two groups (+9.8 ± 6.4 vs +7.2 ± 5.2, p = 0.17). Endothelium-dependent vasomotion at adjacent stent segments is relatively preserved after EES implantation while vasoconstriction was observed after PES implantation. PMID:24794876

  7. Early definite stent thrombosis with everolimus-eluting stents

    PubMed Central

    Naito, Ryo; Miyauchi, Katsumi; Konishi, Hirokazu; Tsuboi, Shuta; Okazaki, Shinya; Daida, Hiroyuki

    2015-01-01

    Key Clinical Message Stent thrombosis (ST) is a serious complication of percutaneous coronary intervention. Several factors are associated with ST, and combination of these factors increase the risk, even in everolimus-eluting stents, which have low risk of ST. We experienced a case of ST caused by limited coronary flow and resistance to antiplatelet agent. PMID:26509023

  8. Development of a pheromone elution rate physical model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A first principle modeling approach is applied to available data describing the elution of semiochemicals from pheromone dispensers. These data include field data for 27 products developed by several manufacturers, including homemade devices, as well as laboratory data collected on three semiochemi...

  9. Stent fracture and restenosis of a paclitaxel-eluting stent.

    PubMed

    Hamilos, Michalis I; Papafaklis, Michail I; Ligthart, Jurgen M; Serruys, Patrick W; Sianos, Georgios

    2005-01-01

    We describe the case of a patient with restenosis six months after stent implantation, at two points where stent fracture had occurred. Fracture is an unusual and probably underestimated cause of restenosis, which acquires special significance in this era of drug-eluting stents. PMID:16422133

  10. Quantitative structure-retention relationships applied to liquid chromatography gradient elution method for the determination of carbonyl-2,4-dinitrophenylhydrazone compounds.

    PubMed

    Cirera-Domènech, Elisenda; Estrada-Tejedor, Roger; Broto-Puig, Francesc; Teixidó, Jordi; Gassiot-Matas, Miquel; Comellas, Lluís; Lliberia, Josep Lluís; Méndez, Alberto; Paz-Estivill, Susanna; Delgado-Ortiz, Maria Rosa

    2013-02-01

    A usual method for the determination of aldehydes and ketones in different matrices consists of a derivatization with 2,4-dinitrophenylhydrazine (DNPH) followed by HPLC-UV analysis. In the present work, a HPLC-UV gradient elution method has been applied to the analysis of 13 aldehydes and ketones-DNPH in automotive emission samples. In addition to these 13 compounds-DNPH, several carbonyl-DNPH compounds (linear, ramified and cyclic, saturated and unsaturated compounds) have been analyzed by HPLC-UV. Quantitative structure-retention relationships (QSRR) methods have been applied to predict the logarithm of capacity factor (logk') of carbonyl-DNPH compounds. According to its physicochemical meaning, combinations of 2 and 3 molecular descriptors have been proposed in order to achieve higher correlation with logk'. Using linear and non-linear QSRR methodologies, the resulting prediction models allowed the screening of the most probable carbonyl-DNPH derivative candidates that correspond to unknown compounds detected in automotive emission samples. This information has been useful for their identification by UPLC(®)-MS/MS. In addition, the chromatographic retention of different carbonyl-DNPH compound families was studied using two HPLC isocratic methods working with two orthogonal stationary phases (octadecylpolyethoxysilane and cyanopropyl). Differences between the retention indexes obtained for each column were used for classifying carbonyl-DNPH into compounds families. PMID:23298845

  11. Ligand-assisted elution chromatography for separation of lanthanides.

    PubMed

    Ling, Lei; Wang, Nien-Hwa Linda

    2015-04-10

    Lanthanides (Ln's) are the major components of rare earth elements, which are critical components of many high-value products. The ions of adjacent Ln's have the same valence and very similar ionic radii. They cannot be separated using conventional adsorption or ion exchange processes. Current production of high-purity Ln's is based on multiple sequential and parallel solvent extraction processes, which require large amounts of toxic solvents and result in serious negative impact on the environment. In this study, a ligand-assisted elution chromatography process for the separation of Ln's was developed for the first time for titania, which is a robust and inexpensive inorganic sorbent. A selective ligand for Ln's, ethylenediaminetetraacetic acid (EDTA), was found to adsorb on the sorbent. The adsorbed EDTA became strong adsorption sites for the Ln's. Desorption of Ln's was driven by reversible reactions of Ln's with EDTA in the mobile phase. The overall sorbent selectivity for the reaction and adsorption process was approximately equal to the ratio of the sorbent selectivity to the ligand selectivity. The separation mechanisms were tested and verified using rate model simulations and experimental data for the separation of praseodymium (Pr), neodymium (Nd), and samarium (Sm). Simulations based on the model were used to design efficient linear gradient elution and stepwise elution processes. The purity and yield of all three Ln's were found to be above 95% in the designed processes. Stepwise elution can be implemented in a continuous process for increasing sorbent productivity and reducing costs for large-scale separation. Ligand assisted elution processes are much simpler and more environmentally friendly than the conventional solvent extraction processes. PMID:25746756

  12. Nanoporous Titanium Surfaces for Sustained Elution of Proteins and Antibiotics

    PubMed Central

    Cassani, Davide A. D.; Variola, Fabio

    2014-01-01

    Current medically relevant metals for prosthetic reconstructions enjoy a relatively good success rate, but their performance drops significantly in patients with compromised health status, and post-surgical infections still remain an important challenge. To address these problems, different nanotechnology-based strategies have been exploited to create implantable metals with an enhanced bioactivity and antibacterial capacities. Among these, oxidative nanopatterning has emerged as a very effective approach to engender nanoporous surfaces that stimulate and guide the activity of adhering cells. The resulting nanoporosity is also attractive because it offers nanoconfined volumes that can be exploited to load bioactive compounds and modulate their release over time. Such extended elution is needed since a single exposure to growth factors and/or antibiotics, for instance, may not be adequate to further sustain bone regeneration and/or to counteract bacterial colonization. In this article, we assessed the capacities of nanoporous titanium surfaces generated by oxidative nanopatterning to provide controlled and sustained elution of proteins and antibiotic molecules. To this end, we have selected bovine serum albumin (BSA) and vancomycin to reflect commonly used compounds, and investigated their adsorption and elution by Fourier-transform infrared (FT-IR) and ultraviolet–visible (UV-VIS) spectroscopy. Our results demonstrate that while the elution of albumin is not significantly affected by the nanoporosity, in the case of vancomycin, nanoporous surfaces provided an extended release. These findings were successively correlated to the establishment of interactions with the surface and physical-entrapment effects exerted by the nanopores, ultimately highlighting their synergistic contribution to the release profiles and thus their importance in the design of nanostructured eluting platforms for applications in medicine. PMID:24633020

  13. Nanoparticles and drug eluting stents for disease detection and treatment

    NASA Astrophysics Data System (ADS)

    Meng, Juan

    This thesis presents the results of experimental and theoretical studies of nanoparticle entry/adhesion to breast cancer cells and adhesion in drug-eluting stents. Atomic Force Microscopy (AFM) techniques are used to quantify the adhesion. The thermodynamics and kinetics concepts are presented for the modeling of nanoparticle entry into breast cancer cells. In the case of the drug-eluting stents studies, a combination of adhesion theory and fracture mechanics concepts is used to estimate the adhesion energies. To investigate the specific accumulation of the functionalized super-paramagnetic iron oxide nanoparticles (SPIONs) in breast cancer cells, a combination of transmission electron microscopy (TEM) and spectrophotometric analysis was used. It is shown that SPIONs conjugated to luteinizing hormone releasing hormone (LHRH) (LHRH-SPIONs), can be used to specifically target breast cancer cells. They also act as contrast enhancement agents during the magnetic resonance imaging (MRI) of breast cancer xenografts. The adhesion between LHRH and breast cancer cells is an important factor for LHRH-SPIONs to target breast cancer cells. AFM techniques were used to quantify adhesion between LHRH peptides and their receptors on breast cancer cells. The adhesion force between LHRH-coated AFM tips and human breast cancer cells is shown to be about five times greater than that between LHRH-coated AFM tips and normal breast cells. This result also suggests that force microscopy can be used for the specific detection of breast cancer cells. Adhesion and fracture mechanics techniques were used to study the adhesion between the drug eluting layer and Parylene C layer coated onto a model drug-eluting stent. AFM force--displacement measurements were used to quantify the adhesion between the parylene C primer and the drug-eluting layer and the cohesion between the three constituents of the drug-eluting layer. Adhesion theories were then used to relate the measured forces to adhesion

  14. Influence of cell disruption and elution on cellulase release of Clostridium straminisolvens (CSK1).

    PubMed

    Wang, Jungang; Li, Jiajia; Liu, Jinhuan; Hua, Binbin; Wang, Xiaofen; Lv, Yucai; Cao, Yanzhuan; Cui, Zongjun

    2014-05-01

    Clostridium straminisolvens (CSK1) is a novel cellulolytic bacterium isolated from a cellulose-degrading bacterial community MC1. In this study, the influence of the following cell disruption and elution methods on CSK1cellulase release was investigated: (1) freezing-thawing, (2) ultrasonication, (3) elution, (4) freezing-thawing following elution, (5) ultrasonication following elution, and lastly (6) high-pressure homogenization following elution. The activity of the cellulases CMCase, β-glucosidase, Avicelase, FPase, and xylanase in crude extracts increased 81.5, 23.8, 87.7, 46.3, and 51.7 %, respectively, with an observed optimal treatment method for each cellulase type. The release of protein from CSK1 cells increased following either cell disruption or elution and was highest at 88.3 % in the homogenization high pressure following elution treatment. A newly observed protein was present following cell elution. The performance of cell elution as determined by real time-PCR indicated that the first time cell elution removed more than 90 % of the CSK1 cells from the substrate. These findings demonstrate that cell disruption and elution are effective methods for inducing cellulase release, and elution is the key step for CSK1. To our knowledge, this study presents the first evidence of optimal treatments for induction of cellulase release of Clostridium straminisolvens. This information will be of great value for use in subsequent efforts to better understand the cellulase characteristics of CSK1 and cellulose degradation mechanisms of the MC1 community. PMID:24728761

  15. A case of early drug-eluting stent fracture.

    PubMed

    Smaldone, Costantino; Bacà, Marco; Niccoli, Giampaolo

    2010-10-01

    Although stent fracture following femoro-popliteal intervention is well recognized, coronary stent fracture represents an underrecognized entity. Its incidence is low but it represents an important clinical entity as it may complicate with stent thrombosis causing acute coronary syndromes, or may predispose to instent restenosis. Although coronary stent fracture may involve both bare metal stents (BMS) and drug-eluting stents (DES), a recent analysis of the literature indicates that reports of stent fracture have increased since DES was introduced. Furthermore, chronic stretch at specific vessel sites as bends may lead to late occurrence of fracture. We present the case of a patient with a non-ST-segment elevation acute coronary syndrome caused by the early fracture of an everolimus-eluting stent (Xience®) implanted only three days before. PMID:20944195

  16. [Coronary aneurysm after drug-eluting stent implantation].

    PubMed

    Paulista, Paulo Paredes; Paulista, Paulo Henrique Dágola; Centemero, Marinella Patrizia; Feres, Fausto

    2008-01-01

    The use of drug-eluting stents aiming at by-pass the disadvantage of stainless steel stents have been associated to late thrombosis after withdrawal of anti-platelet agents. We report a case with another complication, the development of a coronary aneurysm in the stent area more than three years after index procedure. Late chronic local inflammatory responses may be responsible for the weakening, erosion and aneusrysm formation. PMID:18719840

  17. Suppression of scarring in peripheral nerve implants by drug elution

    NASA Astrophysics Data System (ADS)

    FitzGerald, James J.

    2016-04-01

    Objective. Medical implants made of non-biological materials provoke a chronic inflammatory response, resulting in the deposition of a collagenous scar tissue (ST) layer on their surface, that gradually thickens over time. This is a critical problem for neural interfaces. Scar build-up on electrodes results in a progressive decline in signal level because the scar tissue gradually separates axons away from the recording contacts. In regenerative sieves and microchannel electrodes, progressive scar deposition will constrict and may eventually choke off the sieve hole or channel lumen. Interface designs need to address this issue if they are to be fit for long term use. This study examines a novel method of inhibiting the formation and thickening of the fibrous scar. Approach. Research to date has mainly focused on methods of preventing stimulation of the foreign body response by implant surface modification. In this paper a pharmacological approach using drug elution to suppress chronic inflammation is introduced. Microchannel implants made of silicone doped with the steroid drug dexamethasone were implanted in the rat sciatic nerve for periods of up to a year. Tissue from within the microchannels was compared to that from control devices that did not release any drug. Main results. In the drug eluting implants the scar layer was significantly thinner at all timepoints, and unlike the controls it did not continue to thicken after 6 months. Control implants supported axon regeneration well initially, but axon counts fell rapidly at later timepoints as scar thickened. Axon counts in drug eluting devices were initially much lower, but increased rather than declined and by one year were significantly higher than in controls. Significance. Drug elution offers a potential long term solution to the problem of performance degradation due to scarring around neural implants.

  18. Fully bioresorbable drug-eluting coronary scaffolds: A review.

    PubMed

    Charpentier, Emmanuel; Barna, Alexandre; Guillevin, Loïc; Juliard, Jean-Michel

    2015-01-01

    Following the development of stents, then drug-eluting stents (DES), bioresorbable scaffolds are proposed as a third evolution in coronary angioplasty, aiming to reduce the incidence of restenosis and stent thrombosis and to restore vascular physiology. At least 16 such devices are currently under development, but published clinical data were available for only three of them in September 2014. The first device is Abbott's BVS(®), a poly-L-lactic acid (PLLA)-based everolimus-eluting device, which has been tested in a registry and two non-randomized trials. Clinical results seem close to what is expected from a modern DES, but possibly with more post-procedural side-effects. Two randomized trials versus DES are underway. This device is already marketed in many European countries. The second device is Elixir's DESolve(®), a PLLA-based novolimus-eluting device, which has been evaluated in two single-arm trials. Results are not widely different from those expected from a DES. The third device is Biotronik's DREAMS(®), a metallic magnesium-based paclitaxel-eluting device, which has been assessed in an encouraging single-arm trial; its second version is currently undergoing evaluation in a single-arm trial. The available results suggest that the technological and clinical development of bioresorbable scaffolds is not yet complete: their possible clinical benefits are still unclear compared with third-generation DES; the impact of arterial physiology restoration has to be assessed over the long term; and their cost-effectiveness has to be established. From the perspective of a health technology assessment, there is no compelling reason to hasten the clinical use of these devices before the results of ongoing randomized controlled trials become available. PMID:26113479

  19. Advances with polymer-free amphilimus-eluting stents.

    PubMed

    CARRIé, Didier

    2016-06-01

    Despite the improved clinical outcomes following the availability of second generation drug eluting stents (DES), percutaneous coronary intervention (PCI) is associated with worse clinical and angiographic outcomes among the patients with diabetes mellitus (DM) than among non-diabetics. The Cre8 Amphilimus-eluting DES is polymer-free, resulting in a reduced inflammatory response and lower risk of stent thrombosis. In a clinical study, it showed equivalent efficacy and safety in diabetic and non-diabetic populations, a unique finding among DES studies. These findings were confirmed in a real-world study, Investig8, and another real-world study, Particip8, is ongoing. The RESERVOIR Clinical Trial recruited patients with DM and showed noninferiority of the Cre8 DES compared to an everolimus eluting DES (EES) in the overall group but showed a statistical superiority of Cre8 in diabetic patients with higher metabolic dysfunctions. The Cre8 DES is therefore a valuable option for this important patient population. PMID:26934663

  20. Metal elution from Ni- and Fe-based alloy reactors under hydrothermal conditions.

    PubMed

    Faisal, Muhammad; Quitain, Armando T; Urano, Shin-Ya; Daimon, Hiroyuki; Fujie, Koichi

    2004-05-20

    Elution of metals from Ni- and Fe-based alloy (i.e. Inconel 625 and SUS 316) under hydrothermal conditions was investigated. Results showed that metals could be eluted even in a short contact time. At subcritical conditions, a significant amount of Cr was extracted from SUS 316, while only traces of Ni, Fe, Mo, and Mn were eluted. In contrast, Ni was removed in significant amounts compared to Cr when Inconel 625 was tested. Several factors including temperature and contact time were found to affect elution behavior. The presence of air in the fluid even promoted elution under subcritical conditions. PMID:15120875

  1. Experimental characterization of the transport phenomena, adsorption, and elution in a protein A affinity monolithic medium.

    PubMed

    Herigstad, M Omon; Dimartino, Simone; Boi, Cristiana; Sarti, Giulio C

    2015-08-14

    A commercially available convective interaction media (CIM) Protein A monolithic column was fully characterized in view of its application for the affinity capture of IgG in monoclonal antibody production processes. By means of moment analysis, the interstitial porosity and axial dispersion coefficient were determined. The frontal analysis method of characteristic points was employed, for the first time with monolithic media, to determine the dynamic binding capacity. The effects of the flow rate and pH on the total recovery of polyclonal IgG and elution profile were evaluated. A comparison with literature data for Protein A chromatography beads demonstrate the superior bed utilization of monolithic media, which gave better performance at lower residence times. PMID:26143608

  2. WE-G-BRE-08: Radiosensitization by Olaparib Eluting Nanospheres

    SciTech Connect

    Tangutoori, S; Kumar, R; Sridhar, S; Korideck, H; Makrigiorgos, G; Cormack, R

    2014-06-15

    Purpose: Permanent prostate brachytherapy often uses inert bio-absorbable spacers to achieve the desired geometric distribution of sources within the prostate. Transforming these spacers into implantable nanoplatforms for chemo-radiation therapy (INCeRT) provides a means of providing sustained in-situ release of radiosensitizers in the prostate to enhance the therapeutic ratio of the procedure. Olaparib, a PARP inhibitor, suppresses DNA repair processes present during low dose rate continuous irradiation. This work investigates the radiosensitizing/DNA damage repair inhibition by NanoOlaparib eluting nanospheres. Methods: Human cell line PC3 (from ATCC), was maintained in F12-k medium supplemented with fetal bovine serum. Clonogenic assay kit (from Fischer Scientific) was used to fix and stain the cells to determine the long term effects of irradiation. Nanoparticle size and zeta potential of nanospheres were determined using a Zeta particle size analyzer. The incorporation of Olaparib in nanospheres was evaluated by HPLC. Irradiation was performed in a small animal irradiator operating at 220 KeV.The long term effects of radio-sensitization with olaparib and nanoolaparib was determined using the clonogenic assay at 2 Gy and 4 Gy doses. The cells were allowed to grow for around 10 doubling cycles, The colonies were fixed and stained using clonogenic assay kit. The excess stain was washed off using DI water and the images were taken using a digital camera. Results: Radiosensitization studies were carried out in prostate cancer cell line, PC3 radiation at 0, 2 and 4Gy doses. Strongest dose response was observed with nanoolaparib treated cells compared to untreated cells. Conclusion: A two stage drug release of drug eluting nanospheres from a biodegradable spacer has been suggested for sustained in-situ release of Olaparib to suppress DNA repair processes during prostate brachytherapy. The Olaparib eluting nanospheres had the same in-vitro radiosensitizing effect as

  3. Optimization of Drug Delivery by Drug-Eluting Stents

    PubMed Central

    Bozsak, Franz; Gonzalez-Rodriguez, David; Sternberger, Zachary; Belitz, Paul; Bewley, Thomas; Chomaz, Jean-Marc; Barakat, Abdul I.

    2015-01-01

    Drug-eluting stents (DES), which release anti-proliferative drugs into the arterial wall in a controlled manner, have drastically reduced the rate of in-stent restenosis and revolutionized the treatment of atherosclerosis. However, late stent thrombosis remains a safety concern in DES, mainly due to delayed healing of the endothelial wound inflicted during DES implantation. We present a framework to optimize DES design such that restenosis is inhibited without affecting the endothelial healing process. To this end, we have developed a computational model of fluid flow and drug transport in stented arteries and have used this model to establish a metric for quantifying DES performance. The model takes into account the multi-layered structure of the arterial wall and incorporates a reversible binding model to describe drug interaction with the cells of the arterial wall. The model is coupled to a novel optimization algorithm that allows identification of optimal DES designs. We show that optimizing the period of drug release from DES and the initial drug concentration within the coating has a drastic effect on DES performance. Paclitaxel-eluting stents perform optimally by releasing their drug either very rapidly (within a few hours) or very slowly (over periods of several months up to one year) at concentrations considerably lower than current DES. In contrast, sirolimus-eluting stents perform optimally only when drug release is slow. The results offer explanations for recent trends in the development of DES and demonstrate the potential for large improvements in DES design relative to the current state of commercial devices. PMID:26083626

  4. A fractured sirolimus-eluting stent with a coronary aneurysm.

    PubMed

    Kim, Sung Hea; Kim, Hyun Joong; Han, Seong Woo; Jung, Sang Man; Kim, Jun Suk; Chee, Hyun Keun; Ryu, Kyu Hyung

    2009-08-01

    A 55-year-old man had undergone successful percutaneous intervention with a sirolimus-eluting stent, placed in the right coronary artery (2.5 x 33 mm) and distal left circumflex artery (3.0 x 28 mm) without high pressure ballooning. Twelve months later he presented with unstable angina. Angiography revealed two fracture sites on the right coronary artery-deployed stent, with a large aneurysm and an aneurysmal dilatation of the left circumflex artery without stent fracture. Due to the potential risk of aneurysmal rupture, he underwent coronary artery bypass grafting and ligation of the aneurysm. PMID:19632438

  5. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study.

    PubMed

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza; Kassaian, Seyed Ebrahim

    2016-04-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent. PMID:27127426

  6. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study

    PubMed Central

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza

    2016-01-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421–1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent. PMID:27127426

  7. Mathematical modeling of cross-linking monomer elution from resin-based dental composites.

    PubMed

    Manojlovic, Dragica; Radisic, Marina; Lausevic, Mila; Zivkovic, Slavoljub; Miletic, Vesna

    2013-01-01

    Elution of potentially toxic substances, including monomers, from resin-based dental composites may affect the biocompatibility of these materials in clinical conditions. In addition to the amounts of eluted monomers, mathematical modeling of elution kinetics reveals composite restorations as potential chronic sources of leachable monomers. The aim of this work was to experimentally quantify elution of main cross-linking monomers from four commercial composites and offer a mathematical model of elution kinetics. Composite samples (n = 7 per group) of Filtek Supreme XT (3M ESPE), Tetric EvoCeram (Ivoclar Vivadent), Admira (Voco), and Filtek Z250 (3M ESPE) were prepared in 2-mm thick Teflon moulds and cured with halogen or light-emitting diode light. Monomer elution in ethanol and water was analyzed using high-performance liquid chromatography up to 28 days postimmersion. The mathematical model was expressed as a sum of two exponential regression functions representing the first-order kinetics law. Elution kinetics in all cases followed the same mathematical model though differences in rate constants as well as the extent of monomer elution were material-, LCU-, medium-dependent. The proposed mechanisms of elution indicate fast elution from surface and subsurface layers and up to 100 times slower monomer extraction from the bulk polymer. PMID:22997145

  8. Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry.

    PubMed

    Elmongy, Hatem; Ahmed, Hytham; Wahbi, Abdel-Aziz; Amini, Ahmad; Colmsjö, Anders; Abdel-Rehim, Mohamed

    2016-08-01

    A sensitive, accurate and reliable bioanalytical method for the enantioselective determination of metoprolol in plasma and saliva samples utilizing liquid chromatography-electrospray ionization tandem mass spectrometry was developed and validated. Human plasma and saliva samples were pretreated by microextraction by packed sorbent (MEPS) prior to analysis. A new MEPS syringe form with two inputs was used. Metoprolol enantiomers and internal standard pentycaine (IS) were eluted from MEPS sorbent using isopropanol after removal of matrix interferences using aliquots of 5% methanol in water. Complete separation of metoprolol enantiomers was achieved on a Cellulose-SB column (150 × 4.6 mm, 5 μm) using isocratic elution with mobile phase 0.1% ammonium hydroxide in hexane-isopropanol (80:20, v/v) with a flow rate of 0.8 mL/min. A post-column solvent-assisted ionization was applied to enhance metoprolol ionization signal in positive mode monitoring (+ES) using 0.5% formic acid in isopropanol at a flow rate of 0.2 mL/min. The total chromatographic run time was 10 min for each injection. The detection of metoprolol in plasma and saliva samples was performed using triple quadrupole tandem mass spectrometer in +ES under the following mass transitions: m/z 268.08 → 72.09 for metoprolol and m/z 303.3 → 154.3 for IS. The linearity range was 2.5-500 ng/mL for both R- and S-metoprolol in plasma and saliva. The limits of detection and quantitation for both enantiomers were 0.5 and 2.5 ng/mL respectively, in both matrices (plasma and saliva). The intra- and inter-day precisions were presented in terms of RSD values for replicate analysis of quality control samples and were <5%; the accuracy of determinations varied from 96 to 99%. The method was able to determine the therapeutic levels of metoprolol enantiomers in both human plasma and saliva samples successfully, which can aid in therapeutic drug monitoring in clinical laboratories. Copyright © 2016

  9. Numerical modeling of elution peak profiles in supercritical fluid chromatography. Part I-Elution of an unretained tracer

    SciTech Connect

    Kaczmarski, Krzysztof; Guiochon, Georges A

    2010-01-01

    When chromatography is carried out with high-density carbon dioxide as the main component of the mobile phase (a method generally known as 'supercritical fluid chromatography' or SFC), the required pressure gradient along the column is moderate. However, this mobile phase is highly compressible and, under certain experimental conditions, its density may decrease significantly along the column. Such an expansion absorbs heat, cooling the column, which absorbs heat from the outside. The resulting heat transfer causes the formation of axial and radial gradients of temperature that may become large under certain conditions. Due to these gradients, the mobile phase velocity and most physico-chemical parameters of the system (viscosity, diffusion coefficients, etc.) are no longer constant throughout the column, resulting in a loss of column efficiency, even at low flow rates. At high flow rates and in serious cases, systematic variations of the retention factors and the separation factors with increasing flow rates and important deformations of the elution profiles of all sample components may occur. The model previously used to account satisfactorily for the effects of the viscous friction heating of the mobile phase in HPLC is adapted here to account for the expansion cooling of the mobile phase in SFC and is applied to the modeling of the elution peak profiles of an unretained compound in SFC. The numerical solution of the combined heat and mass balance equations provides temperature and pressure profiles inside the column, and values of the retention time and efficiency for elution of this unretained compound that are in excellent agreement with independent experimental data.

  10. Corrosion of mild steel in simulated cesium elution process solutions

    SciTech Connect

    Elmore, M.R.

    1996-09-01

    The West Valley Support Project is being conducted to meet technology needs for the West Valley Demonstration Project and to provide support to the site cleanup and stabilization activities, which involves removing residual Cs in Tank 8D-1 after waste retrieval. In-tank oxalic acid elution of Cs-loaded zeolite is being evaluated. The work reported here involved evaluating the potential for increased corrosion of Tank 8D-1 during Cs elution, because oxalic acid is corrosive to carbon steel. This included corrosion tests with mild steel (A516 Grade 55) at 27-50 C with 4 and 8 wt% oxalic acid, for 2, 4, and 6 days. Results agreed with Sept. 1995 tests at 50 C for 1-3 weeks. Corrosion rate of A516 Grade 55 mild steel in oxalic acid is quite high (about 150 mils/y or 3.8 mm/y). Corrosion increased three- or fourfold going from 27 to 50 C. Although the tests resulted in a very rough surface appearance, indicating potential for localized corrosion, eg, pitting and crevice corrosion, the exposure times used were apparently too short to initiate pitting.

  11. Drug-Eluting Fibers for HIV-1 Inhibition and Contraception

    PubMed Central

    Ball, Cameron; Krogstad, Emily; Chaowanachan, Thanyanan; Woodrow, Kim A.

    2012-01-01

    Multipurpose prevention technologies (MPTs) that simultaneously prevent sexually transmitted infections (STIs) and unintended pregnancy are a global health priority. Combining chemical and physical barriers offers the greatest potential to design effective MPTs, but integrating both functional modalities into a single device has been challenging. Here we show that drug-eluting fiber meshes designed for topical drug delivery can function as a combination chemical and physical barrier MPT. Using FDA-approved polymers, we fabricated nanofiber meshes with tunable fiber size and controlled degradation kinetics that facilitate simultaneous release of multiple agents against HIV-1, HSV-2, and sperm. We observed that drug-loaded meshes inhibited HIV-1 infection in vitro and physically obstructed sperm penetration. Furthermore, we report on a previously unknown activity of glycerol monolaurate (GML) to potently inhibit sperm motility and viability. The application of drug-eluting nanofibers for HIV-1 prevention and sperm inhibition may serve as an innovative platform technology for drug delivery to the lower female reproductive tract. PMID:23209601

  12. Drug-eluting fibers for HIV-1 inhibition and contraception.

    PubMed

    Ball, Cameron; Krogstad, Emily; Chaowanachan, Thanyanan; Woodrow, Kim A

    2012-01-01

    Multipurpose prevention technologies (MPTs) that simultaneously prevent sexually transmitted infections (STIs) and unintended pregnancy are a global health priority. Combining chemical and physical barriers offers the greatest potential to design effective MPTs, but integrating both functional modalities into a single device has been challenging. Here we show that drug-eluting fiber meshes designed for topical drug delivery can function as a combination chemical and physical barrier MPT. Using FDA-approved polymers, we fabricated nanofiber meshes with tunable fiber size and controlled degradation kinetics that facilitate simultaneous release of multiple agents against HIV-1, HSV-2, and sperm. We observed that drug-loaded meshes inhibited HIV-1 infection in vitro and physically obstructed sperm penetration. Furthermore, we report on a previously unknown activity of glycerol monolaurate (GML) to potently inhibit sperm motility and viability. The application of drug-eluting nanofibers for HIV-1 prevention and sperm inhibition may serve as an innovative platform technology for drug delivery to the lower female reproductive tract. PMID:23209601

  13. Precision control of eluted activity from a Sr/Rb generator for cardiac positron emission tomography.

    PubMed

    Klein, R; Adler, A; Beanlands, R S; deKemp, R A

    2004-01-01

    A rubidium-82 (/sup 82/Rb) elution system is described for use with clinical positron emission tomography. The system is self-calibrating with 1.4% repeatability, independent of generator activity and elution flow rate. Saline flow is switched between a /sup 82/Sr//sup 82/Rb generator and a bypass line to achieve a constant activity elution of /sup 82/Rb. In the present study, pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control algorithm is developed which produces a constant activity elution within the constraints of long feedback delay and short elution time. Accurate constant-activity elutions of 10-70% of the total generator activity were demonstrated using the threshold comparison control. The adaptive-corrective control of the PWM valve provided a substantial improvement in precision of the steady-state output. PMID:17271953

  14. Multiple Stent Fractures After Everolimus-Eluting Stent Implantation Causing Acute Myocardial Infarction

    PubMed Central

    Ji, Eun Young; Park, Gyung-Min; Kim, Dae Won; Kim, Tae-Seok; Kim, Chan Joon; Cho, Jung Sun; Park, Mahn-Won; Her, Sung Ho

    2016-01-01

    Abstract Stent fracture is an uncommon complication of drug-eluting stent implantation, but it has a clinical significance because of its potential association with adverse cardiac events such as in-stent restenosis, target lesion revascularization, and stent thrombosis. Multiple stent fractures account for a small proportion, but they may lead to more serious complications. Newer generation drug-eluting stents are designed for improved safety and efficacy compared with early generation drug-eluting stents. Multiple stent fractures after newer generation drug-eluting stent implantation are a rare case. We report a case of 25-year-old male who presented with acute myocardial infarction caused by multiple stent fractures after everolimus-eluting stents implantation and was treated by balloon angioplasty. Physicians should be aware of the possibility of multiple stent fractures even after newer generation drug-eluting stent implantation. PMID:26871806

  15. Comparison of DNA extraction kits and modification of DNA elution procedure for the quantitation of subdominant bacteria from piggery effluents with real-time PCR

    PubMed Central

    Desneux, Jérémy; Pourcher, Anne-Marie

    2014-01-01

    Four commercial DNA extraction kits and a minor modification in the DNA elution procedure were evaluated for the quantitation of bacteria in pig manure samples. The PowerSoil®, PowerFecal®, NucleoSpin® Soil kits and QIAamp® DNA Stool Mini kit were tested on raw manure samples and on lagoon effluents for their ability to quantify total bacteria and a subdominant bacteria specific of pig manure contamination: Lactobacillus amylovorus. The NucleoSpin® Soil kit (NS kit), and to a lesser extent the PowerFecal® kit were the most efficient methods. Regardless of the kit utilized, the modified elution procedure increased DNA yield in the lagoon effluent by a factor of 1.4 to 1.8. When tested on 10 piggery effluent samples, compared to the QIAamp kit, the NS kit combined with the modified elution step, increased by a factor up to 1.7 log10 the values of the concentration of L. amylovorus. Regardless of the type of manure, the best DNA quality and the highest concentrations of bacteria were obtained using the NS kit combined with the modification of the elution procedure. The method recommended here significantly improved quantitation of subdominant bacteria in manure. PMID:24838631

  16. Comparison of DNA extraction kits and modification of DNA elution procedure for the quantitation of subdominant bacteria from piggery effluents with real-time PCR.

    PubMed

    Desneux, Jérémy; Pourcher, Anne-Marie

    2014-08-01

    Four commercial DNA extraction kits and a minor modification in the DNA elution procedure were evaluated for the quantitation of bacteria in pig manure samples. The PowerSoil(®), PowerFecal(®), NucleoSpin(®) Soil kits and QIAamp(®) DNA Stool Mini kit were tested on raw manure samples and on lagoon effluents for their ability to quantify total bacteria and a subdominant bacteria specific of pig manure contamination: Lactobacillus amylovorus. The NucleoSpin(®) Soil kit (NS kit), and to a lesser extent the PowerFecal(®) kit were the most efficient methods. Regardless of the kit utilized, the modified elution procedure increased DNA yield in the lagoon effluent by a factor of 1.4 to 1.8. When tested on 10 piggery effluent samples, compared to the QIAamp kit, the NS kit combined with the modified elution step, increased by a factor up to 1.7 log10 the values of the concentration of L. amylovorus. Regardless of the type of manure, the best DNA quality and the highest concentrations of bacteria were obtained using the NS kit combined with the modification of the elution procedure. The method recommended here significantly improved quantitation of subdominant bacteria in manure. PMID:24838631

  17. Microfluidic Fabrication of MEAN-Eluting Magnetic Microspheres

    PubMed Central

    Kim, Dong-Hyun; Choy, Terence; Huang, Sui; Green, Richard M; Omary, Reed A.; Larson, Andrew C.

    2014-01-01

    Recently, 6-methoxyethylamino numonafide (MEAN) exhibited potent inhibition of hepatocellular carcinoma (HCC) cell growth and less systemic toxicity than amonafide. MEAN may serve as an ideal candidate for the treatment of HCC; however, liver-directed, selective infusion methods may be critical to maximize MEAN dose delivered to the targeted tumors. Our study describes the microfluidic fabrication of MEAN-eluting ultrasmall superparamagnetic iron oxide (USPIO) nanocluster-containing alginate microspheres (MEAN-magnetic microspheres) intended for selective transcatheter delivery to hepatocellular carcinoma. The resulting drug delivery platform was mono-disperse, microsphere sizes were readily controlled based upon channel flow rates during synthesis procedures, and drug release rates from the microspheres could be readily controlled with the introduction of USPIO nanoclusters. The MR relaxivity properties of the microspheres suggest the feasibility of in vivo imaging after administration and these microspheres exhibited potent therapeutic effects significantly inhibiting cell growth inducing apoptosis in hepatoma cells. PMID:24161384

  18. Drug-eluting stents to prevent stent thrombosis and restenosis.

    PubMed

    Im, Eui; Hong, Myeong-Ki

    2016-01-01

    Although first-generation drug-eluting stents (DES) have significantly reduced the risk of in-stent restenosis, they have also increased the long-term risk of stent thrombosis. This safety concern directly triggered the development of new generation DES, with innovations in stent platforms, polymers, and anti-proliferative drugs. Stent platform materials have evolved from stainless steel to cobalt or platinum-chromium alloys with an improved strut design. Drug-carrying polymers have become biocompatible or biodegradable and even polymer-free DES were introduced. New limus-family drugs (such as everolimus, zotarolimus or biolimus) were adopted to enhance stent performances. As a result, these new DES demonstrated superior vascular healing responses on intracoronary imaging studies and lower stent thrombotic events in actual patients. Recently, fully-bioresorbable stents (scaffolds) have been introduced, and expanding their applications. In this article, the important concepts and clinical results of new generation DES and bioresorbable scaffolds are described. PMID:26567863

  19. Drug-eluting stents to prevent reblockage of coronary arteries.

    PubMed

    Schwertz, Dorie W; Vaitkus, Paul

    2003-01-01

    Restenosis limits the success of percutaneous transluminal coronary interventions. Coronary artery stenting decreases restenosis, improves outcomes, and is currently the most commonly used percutaneous coronary intervention in the United States. However, in-stent restenosis continues to occur at an unacceptable rate. In-stent restenosis is a neointimal hyperplastic response resulting primarily from vascular smooth muscle cell proliferation. Treatment with anti-proliferative agents presents a logical approach to eradicating restenosis, however, these drugs are highly toxic. Coating stents with anti-proliferative agents allows local delivery of high doses and avoids systemic side effects. In 2001, the results of two clinical trials, RAVEL and ELUTES, using sirolimus- and paclitaxil-coated stents demonstrated nearly complete elimination of in-stent restenosis. These dramatic results represent a tremendous advance in the treatment of coronary heart disease. PMID:12537084

  20. Neoatherosclerosis after Drug-Eluting Stent Implantation: Roles and Mechanisms

    PubMed Central

    Cui, Yuanyuan; Shi, Dazhuo; Chen, Keji

    2016-01-01

    In-stent neoatherosclerosis (NA), characterized by a relatively thin fibrous cap and large volume of yellow-lipid accumulation after drug-eluting stents (DES) implantation, has attracted much attention owing to its close relationship with late complications, such as revascularization and late stent thrombosis (ST). Accumulating evidence has demonstrated that more than one-third of patients with first-generation DES present with NA. Even in the advent of second-generation DES, NA still occurs. It is indicated that endothelial dysfunction induced by DES plays a critical role in neoatherosclerotic development. Upregulation of reactive oxygen species (ROS) induced by DES implantation significantly affects endothelial cells healing and functioning, therefore rendering NA formation. In light of the role of ROS in suppression of endothelial healing, combining antioxidant therapies with stenting technology may facilitate reestablishing a functioning endothelium to improve clinical outcome for patients with stenting.

  1. In vivo Evaluation of Cenderitide-Eluting Stent (CES) II.

    PubMed

    Huang, Yingying; Ng, Xu Wen; Lim, Soon Ghim; Chen, Horng Haur; Burnett, John C; Boey, Yin Chiang Freddy; Venkatraman, Subbu S

    2016-02-01

    The use of drug-eluting coronary stents has led to significant reduction in in-stent restenosis (ISR), but led to delayed endothelialization, necessitating the prolonged use of expensive anti-thrombotic drugs with their side-effects. Cenderitide (CD-NP) is a novel anti-proliferative chimeric peptide of semi-endothelial origin. Our previous work in vitro has demonstrated; that the smooth muscle cells were inhibited significantly more than endothelial cells which is the desirable feature of an anti-restenosis drug. This work reports the effects of implantation of a centeritide-eluting stent (CES) on ISR and endothelialization in an in vivo model. CESs were produced by coating bare metallic stents with CD-NP entrapped in biodegradable poly(ε-caprolactone) using an ultrasonic spray coater. A total of 32 stents were successfully implanted into 16 pigs, and all animal survived for 28 days. The plasma levels of CD-NP were significantly higher in the CES group than in the control group (bare metal stents and polymer-coated stent) at post-stenting, indicating the successful release of CD-NP from the stent in vivo. Furthermore, SEM analysis results showed the greater endothelial coverage of the stent struts, as well as between the struts in CES group. Moreover, histological results showed mild inflammation, and low fibrin score at 28 days. However, plasma cGMP (second messenger, cyclic 3',5' guanosine monophosphate) does not show a significant difference, and the CES is also unable to show significant difference in terms on neointimal area and stenosis, in comparison to BMS at 28 days. PMID:26178873

  2. Determinants of protein elution rates from preparative ion-exchange adsorbents.

    PubMed

    Angelo, James M; Lenhoff, Abraham M

    2016-04-01

    The rate processes involved in elution in preparative chromatography can affect both peak resolution and hence selectivity as well as practical factors such as facility fit. These processes depend on the physical structure of the adsorbent particles, the amount of bound solute, the solution conditions for operation or some combination of these factors. Ion-exchange adsorbents modified with covalently attached or grafted polymer layers have become widely used in preparative chromatography. Their often easily accessible microstructures offer substantial binding capacities for biomolecules, but elution has sometimes been observed to be undesirably slow. In order to determine which physicochemical phenomena control elution behavior, commercially available cellulosic, dextran-grafted and unmodified agarose materials were characterized here by their elution profiles at various conditions, including different degrees of loading. Elution data were analyzed under the assumption of purely diffusion-limited control, including the role of pore structure properties such as porosity and tortuosity. In general, effective elution rates decreased with the reduction of accessible pore volume, but differences among different proteins indicated the roles of additional factors. Additional measurements and analysis, including the use of confocal laser scanning microscopy to observe elution within single chromatographic particles, indicated the importance of protein association within the particle during elution. The use of protein stabilizing agents was explored in systems presenting atypical elution behavior, and l-arginine and disaccharide excipients were shown to alleviate the effects for one protein, lysozyme, in the presence of sodium chloride. Incorporation of these excipients into eluent buffer gave rise to faster elution and significantly lower pool volumes in elution from polymer-modified adsorbents. PMID:26948763

  3. Zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost.

    PubMed

    Arat Ozkan, Alev; Sinan, Umit Yasar; Gurmen, Aziz T

    2016-01-01

    Stent fracture is a rare complication of drug-eluting stent implantation with a reported rate of 0.84%-3.2% in various clinical studies with first-generation drug-eluting stents and 29% in autopsy studies. Sirolimus-eluting stents with their closed cell design were reported to be more prone to fracture compared to paclitaxel-eluting stents. Other risk factors for stent fracture are multiple stenting, longer stent length, chronic renal failure, right coronary artery intervention, and a higher maximal inflation pressure. The role of angiography in diagnosing stent fracture is limited, a fact also questioning the reliability of angiographic data. Image enhancement techniques like StentBoost are widely available in new-generation angiography systems and are used to assess stent expansion, overlap size, or to localize the postdilation balloon. Here, we report a case of zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost. PMID:27489714

  4. Zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost

    PubMed Central

    Arat Ozkan, Alev; Sinan, Umit Yasar; Gurmen, Aziz T

    2016-01-01

    Stent fracture is a rare complication of drug-eluting stent implantation with a reported rate of 0.84%–3.2% in various clinical studies with first-generation drug-eluting stents and 29% in autopsy studies. Sirolimus-eluting stents with their closed cell design were reported to be more prone to fracture compared to paclitaxel-eluting stents. Other risk factors for stent fracture are multiple stenting, longer stent length, chronic renal failure, right coronary artery intervention, and a higher maximal inflation pressure. The role of angiography in diagnosing stent fracture is limited, a fact also questioning the reliability of angiographic data. Image enhancement techniques like StentBoost are widely available in new-generation angiography systems and are used to assess stent expansion, overlap size, or to localize the postdilation balloon. Here, we report a case of zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost. PMID:27489714

  5. From drug eluting stents to bioresorbable scaffolds; to new horizons in PCI.

    PubMed

    Tenekecioglu, Erhan; Bourantas, Christos; Abdelghani, Mohammad; Zeng, Yaping; Silva, Rafael Cavalcante; Tateishi, Hiroki; Sotomi, Yohei; Onuma, Yoshinobu; Yılmaz, Mustafa; Serruys, Patrick W

    2016-03-01

    Drug eluting stents and particularly the fully bioresorbable drug-eluting scaffolds herald a new era in percutaneous treatment of coronary artery disease. There has been tremendous progress in drug eluting stents with fully biodegradable coating polymers and polymer-free devices with reservoir technology planting the anti-proliferative drug. Despite significant decreases in in-stent restenosis rates with drug eluting stents, limitations still remain before we are able to develop fully bioresorbable scaffolds. Enhanced mechanical flexibility that provides superior conformability to the vessel wall, resumption of the vasoreactivity in the follow-up period and improving visualization on non-invasive imaging modalities are some of the supremacies of the fully bioresorbable scaffolds. In this review, we aim to give a general view on the latest developments in metallic drug eluting stents and fully bioresorbable scaffolds. PMID:26782080

  6. Selective elution of HLA antigens and beta 2-microglobulin from human platelets by chloroquine diphosphate

    SciTech Connect

    Kao, K.J.

    1988-01-01

    To determine whether chloroquine can specifically elute HLA antigens and beta 2-microglobulin (beta 2-M) from the platelet surface, quantitative immunofluorescence flow cytometry and monoclonal antibodies were used to show that HLA antigens and beta 2-M were proportionally eluted from the platelet surface without affecting the membrane glycoproteins IIb and IIIa. Second, an autoradiogram of electrophoresed I-125-labeled platelets showed that only beta 2-M but not other I-125-labeled membrane proteins could be eluted. Although HLA antigens were poorly labeled by I-125 and could not be detected on the autoradiogram, the eluted HLA antigens could be detected by anti-HLA monoclonal antibody and immunoblotting techniques. No loss of plasma membrane integrity was observed by transmission electron microscopy after chloroquine treatment of platelets. The results indicate that chloroquine selectively elutes HLA antigens and their noncovalently associated beta 2-M without affecting other integral platelet membrane proteins.

  7. Spatiotemporal dynamics of doxorubicin elution from embolic beads within a microfluidic network.

    PubMed

    Carugo, Dario; Capretto, Lorenzo; Roy, Bibhas; Carboni, Michele; Caine, Marcus; Lewis, Andrew L; Hill, Martyn; Chakraborty, Suman; Zhang, Xunli

    2015-09-28

    Anticancer treatment using embolic drug-eluting beads (DEBs) has shown multifarious advantages compared to systemic chemotherapy. However, there is a growing need for a better understanding of the physical parameters governing drug-elution from embolic devices under physiologically relevant fluidic conditions. In the present study, we investigated the spatiotemporal dynamics of doxorubicin hydrochloride elution from drug-loaded hydrogel embolic beads within a microfluidic device consisting of a network of interconnected microchannels which replicates the architectural properties of microvascular systems. Drug-elution has been investigated experimentally at a single-bead level, using in-house developed microscopy- and spectrofluorimetry-based methods. Results demonstrated that the kinetics of drug-elution and the amount of eluted drug strongly depended on the location of the embolic event within the embolised channel (e.g. fractional amount of eluted drug after 3h was equal to ~0.2 and ~0.6 for completely-confined and partially-confined bead, respectively). Drug-elution from partially-confined bead showed a counterintuitive dependence on the local Reynolds number (and thus on the mean fluid velocity), as a result of dynamic changes in bead compressibility causing the displacement of the bead from the primary embolic site. Conversely, the kinetics of drug-elution from fully-confined bead was less affected by the local Reynolds number and bead displayed faster elution from the surface area exposed to the systemic flow, which was associated with the formation of fluid eddies nearby the bead post embolisation. PMID:26160306

  8. Prognostic Significance of Polymer Coatings in Zotarolimus-Eluting Stents.

    PubMed

    Iqbal, M Bilal; Nadra, Imad J; Din, Jehangir N; Hendry, Cara; Ding, Lillian; Fung, Anthony; Aymong, Eve; Chan, Albert W; Hodge, Steven; Robinson, Simon D; Della Siega, Anthony

    2016-03-01

    Polymer coatings on drug-eluting stents (DES) serve as a vehicle for delivery of antirestenotic drugs. Whether they influence outcomes for contemporary DES is unknown. The evolution of polymer coatings for zotarolimus-eluting stents (ZES) provides a natural experiment that facilitates such analysis. The Resolute ZES (R-ZES) uses the same antirestenotic drug as the Endeavor ZES (E-ZES) but has a more biocompatible polymer with enhanced drug release kinetics. However, there are limited data on the real-world comparative efficacy of R-ZES and the preceding E-ZES. Thus, we analyzed 17,643 patients who received either E-ZES or R-ZES from 2008 to 2014 from the British Columbia Cardiac Registry. A total of 9,869 patients (56%) received E-ZES and 7,774 patients (44%) received R-ZES. Compared with E-ZES, R-ZES was associated with lower 2-year mortality (4.1% vs 6.4%, p <0.001) and 2-year target vessel revascularization (TVR; 6.8% vs 10.7%, p <0.001). R-ZES use was an independent predictor of lower mortality rate and TVR. This was confirmed in propensity-matched analyses for 2-year mortality (hazard ratio [HR] 0.59, 95% CI 0.49 to 0.71, p <0.001) and 2-year TVR (HR 0.86, 95% CI 0.75 to 0.98, p = 0.032). Instrumental variable analyses demonstrated R-ZES to be associated with lower 2-year mortality (Δ = -2.2%, 95% CI -4.3% to -0.2%, p = 0.032) and 2-year TVR (Δ = -3.3% to 95% CI -6.1% to -0.7%, p = 0.015). Acknowledging the limitations of observational analyses, this study has shown that R-ZES was associated with lower long-term TVR and mortality. These data are reassuring for the newer R-ZES and demonstrate how polymer coatings may influence the clinical performance of DES with wider implications for future DES development and design. PMID:26796194

  9. Sequential Elution Interactome Analysis of the Mind Bomb 1 Ubiquitin Ligase Reveals a Novel Role in Dendritic Spine Outgrowth*

    PubMed Central

    Mertz, Joseph; Tan, Haiyan; Pagala, Vishwajeeth; Bai, Bing; Chen, Ping-Chung; Li, Yuxin; Cho, Ji-Hoon; Shaw, Timothy; Wang, Xusheng; Peng, Junmin

    2015-01-01

    The mind bomb 1 (Mib1) ubiquitin ligase is essential for controlling metazoan development by Notch signaling and possibly the Wnt pathway. It is also expressed in postmitotic neurons and regulates neuronal morphogenesis and synaptic activity by mechanisms that are largely unknown. We sought to comprehensively characterize the Mib1 interactome and study its potential function in neuron development utilizing a novel sequential elution strategy for affinity purification, in which Mib1 binding proteins were eluted under different stringency and then quantified by the isobaric labeling method. The strategy identified the Mib1 interactome with both deep coverage and the ability to distinguish high-affinity partners from low-affinity partners. A total of 817 proteins were identified during the Mib1 affinity purification, including 56 high-affinity partners and 335 low-affinity partners, whereas the remaining 426 proteins are likely copurified contaminants or extremely weak binding proteins. The analysis detected all previously known Mib1-interacting proteins and revealed a large number of novel components involved in Notch and Wnt pathways, endocytosis and vesicle transport, the ubiquitin-proteasome system, cellular morphogenesis, and synaptic activities. Immunofluorescence studies further showed colocalization of Mib1 with five selected proteins: the Usp9x (FAM) deubiquitinating enzyme, alpha-, beta-, and delta-catenins, and CDKL5. Mutations of CDKL5 are associated with early infantile epileptic encephalopathy-2 (EIEE2), a severe form of mental retardation. We found that the expression of Mib1 down-regulated the protein level of CDKL5 by ubiquitination, and antagonized CDKL5 function during the formation of dendritic spines. Thus, the sequential elution strategy enables biochemical characterization of protein interactomes; and Mib1 analysis provides a comprehensive interactome for investigating its role in signaling networks and neuronal development. PMID:25931508

  10. Silver ions eluted from partially protected silver nanoparticles.

    PubMed

    Heidari Zare, Hamideh; Düttmann, Oliver; Vass, Attila; Franz, Gerhard; Jocham, Dieter

    2016-01-01

    The most prominent character of a new type of antibacterial urological catheters is the zebra-stripe pattern of a silver film, which is plated electroless on their interior wall and capped by a very thin semipermeable layer of parylene. This design effectively controls the release rate of Ag(+) ions in artificial urine, which has been measured as function of time with optical emission spectroscopy. By evaluating the minimum inhibitory concentration against certain strains of bacteria with solutions of AgNO3 of known concentration with the method of optical density and applying this analysis to the silver-eluting catheters, it was shown that this moderation prolongs the period of their application significantly. But to act as antibacterial agent in chlorine-containing solutions, as in urine, the presence of urea is required to avoid precipitation of AgCl and to meet or even exceed the minimum inhibitory concentration of Ag(+). The quality of the silver depot layer was further determined by the deposition rate and its morphology, which revealed that the film consisted of grains with a mean size of 150 nm. PMID:27400747

  11. Antiplatelet therapy after drug-eluting stent implantation.

    PubMed

    Warren, Josephine; Baber, Usman; Mehran, Roxana

    2015-02-01

    Dual antiplatelet therapy (DAPT), which is the combination of aspirin and a platelet P2Y12 inhibitor, is the cornerstone of secondary prevention in ischemic heart disease requiring intracoronary stenting. Although the efficacy of DAPT in the reduction of ischemic events has been well validated, the optimal duration, and indeed combination, of therapy is yet to be established. This area continues to attract debate with new developments in stent design and antiplatelet agents, as well as evolving clinical skill levels. Presently, clinical guidelines advocate the use of DAPT for 6-12 months following drug-eluting stent (DES) implantation, but this can vary according to clinical indication, bleeding risk, and country of practice. Concerns have arisen that unnecessary prolongation of DAPT may be associated with increased bleeding events, as well as cost. Whether these guidelines effectively cater to current stenting techniques, devices, and antiplatelet agents remains to be determined. This review analyzes contemporary issues surrounding DAPT following DES implantation, as researchers continue to seek to strike the optimal balance between bleeding and thrombotic risk. Although reduced DAPT durations continue to show promising results in preventing ischemic events while also mitigating bleeding risk, ultimately the consideration of clinical presentation as well as medical and social history is paramount to guiding the optimal duration and cessation of DAPT. PMID:25467922

  12. The ultimate band compression factor in gradient elution chromatography

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2008-01-01

    The equations predicting the ultimate time band compression factor, G = (t{sub R}-t{sub F})/t{sub p} in linear gradient elution chromatography, for an infinitely narrow injection (injection time t{sub p} {yields} 0) were derived for an ideal-model column (dispersionless chromatography, H = 0) assuming the Linear Solvent Strength Model for the retention behavior of the analyte. Numerical solutions can readily be obtained when the LSSM model does not apply. The results can be generalized to any retained organic modifier (k'{sub A}) in the mobile phase. The stronger the retention of the organic modifier, the more effective the band compression. Dispersion in real chromatographic column (H {ne} 0) affects the limits that can be reached in linear gradients but poorly in step gradients. Examples based on a conventional HETP of about 12 {micro}m using a 5 {micro}m particle packed column reveal that the best time compression factor that could be expected is twice the one predicted with an ideal column.

  13. Bone healing by sterilizable calcium phosphate tetrapods eluting osteogenic molecules.

    PubMed

    Maeda, Yujiro; Hojo, Hironori; Shimohata, Nobuyuki; Choi, Sungjin; Yamamoto, Kenichi; Takato, Tsuyoshi; Chung, Ung-il; Ohba, Shinsuke

    2013-07-01

    Although bone grafts and prosthetic implants have shown some clinical success in the treatment of bone defects, the graft availability, biocompatibility, function, and longevity still remain to be improved. One possible solution to these problems is to develop bone implants acting on host cells to induce rapid bone regeneration. Here, we demonstrate bone healing by means of a sterilizable and osteogenic molecule-eluting implant system in which two small molecules, a smoothened agonist (SAG) and a helioxanthin derivative (TH), are loaded onto tetrapod-shaped calcium phosphate granules (Tetrabone). We succeeded in directing progenitor cells toward mature osteoblasts with the combined application of the two small molecules acting on different stages of osteogenesis. Tetrabone released SAG and TH for prolonged periods when loaded with these molecules. EOG sterilization did not affect the osteogenic activity of the SAG- and TH-loaded Tetrabones. The combinatorial use of SAG- and TH-loaded Tetrabones achieved bone healing without cell transplantation in a rat femur bone defect model within two weeks. This system will allow us to vary the combination rate of implants loaded with different osteogenic factors depending on the types and sizes of defects, potentially allowing full temporal and spatial control of the bone regeneration. PMID:23623228

  14. Drug-Eluting Stent: A Review and Update

    PubMed Central

    Htay, Thein; Liu, Ming W

    2005-01-01

    The development of stent has been a major advance in the treatment of obstructive coronary artery disease since the introduction of balloon angioplasty. However, neointimal hyperplasia occurring within the stent leading to in-stent restenosis is a main obstacle in the long-term success of percutaneous coronary intervention (PCI). The recent introduction of drug-eluting stents (DES) contributes a major breakthrough to interventional cardiology. Many large randomized clinical trials using DES have shown a remarkable reduction in angiographic restenosis and target vessel revascularization when compared with bare metal stents. The results of these trials also appear to be supported by evidence from everyday practice and noncontrolled clinical trials. However, the expanded applications of DES, especially in treating complex lesions such as left main trunk, bifurcation, saphenous vein graft lesions, or in-stent restenosis, are still under evaluation with ongoing studies. With the availability of different types of DES in the market, the issue of cost should not be a deterrent and DES will eventually be an economically viable option for all patients. The adoption of DES in all percutaneous coronary intervention may become a reality in the near future. In this review article, we summarize the recent development and progress of DES as well as compare and update the results of clinical trials. PMID:17315599

  15. EVALUATION OF POTENTIAL ELUANTS FOR NON-ACID ELUTION OF CESIUM FROM SPHERICAL RESORCINOL-FORMALDEHYDE RESIN

    SciTech Connect

    Adu-Wusu, K.; Nash, C.; Pennebaker, F.

    2011-10-23

    Ion Exchange column loading and elution of cesium from spherical resorcinol-formaldehyde resin have been conducted for two potential non-acid eluants -(NH{sub 4}){sub 2}CO{sub 3} and CH{sub 3}COONH{sub 4}. The results revealed encouraging cesium elution performance. 100% elution was achieved in at most 22 hours ({approx}28 bed volumes) of elution. Elution performance was fairly high at 6 hours ({approx}8 bed volumes) of elution for some of the eluants and also practically comparable to the benchmark acid eluant (HNO{sub 3}). Hence, it is quite possible 100% percent elution will be closer to the 6th hour than the 22nd hour. Elution is generally enhanced by increasing the concentration and pH of the eluants, and combining the eluants.

  16. Characterization of drug-eluting stent (DES) materials with cluster secondary ion mass spectrometry (SIMS)

    NASA Astrophysics Data System (ADS)

    Mahoney, Christine M.; Patwardhan, Dinesh V.; Ken McDermott, M.

    2006-07-01

    Secondary ion mass spectrometry (SIMS) employing an SF 5+ polyatomic primary ion source was utilized to analyze several materials commonly used in drug-eluting stents (DES). Poly(ethylene- co-vinyl acetate) (PEVA), poly(lactic- co-glycolic acid) (PLGA) and various poly(urethanes) were successfully depth profiled using SF 5+ bombardment. The resultant molecular depth profiles obtained from these polymeric films showed very little degradation in molecular signal as a function of increasing SF 5+ primary ion dose when experiments were performed at low temperatures (signal was maintained for doses up to ˜5 × 10 15 ions/cm 2). Temperature was determined to be an important parameter in both the success of the depth profiles and the mass spectral analysis of the polymers. In addition to the pristine polymer films, paclitaxel (drug released in Taxus™ stent) containing PLGA films were also characterized, where it was confirmed that both drug and polymer signals could be monitored as a function of depth at lower paclitaxel concentrations (10 wt%).

  17. Total protein quantitation using the bicinchoninic acid assay and gradient elution moving boundary electrophoresis.

    PubMed

    Kralj, Jason G; Munson, Matthew S; Ross, David

    2014-07-01

    We investigated the ability of gradient elution moving boundary electrophoresis (GEMBE) with capacitively coupled contactless conductivity detection (C(4) D) to assay total protein concentration using the bicinchoninic acid (BCA) reaction. We chose this format because GEMBE-C(4) D behaves as a concentration dependent detection system, unlike optical methods that also rely on pathlength (due to Beer's law). This system tolerates proteins well compared with other capillary electrophoretic methods, allowing the capillary to be reused without coatings or additional hydroxide wash steps. The typical reaction protocol was modified by reducing the pH slightly from 11.25 to 9.4, which enabled elimination of tartrate from the reagents. We estimated that copper (I) could be detected at approximately 3.0 μmol/L, which agrees with similar GEMBE and CZE systems utilizing C(4) D. Under conditions similar to the BCA "micro method" assay, we determined the LOD for three common proteins (insulin, BSA, and bovine gamma globulin) and found that they agree well with the existing spectroscopic detection methods. Further, we investigated how long reaction times impact the LOD and found that the conversion was proportional to log(time). This indicated that little sensitivity is gained by extending the reaction past 1 h. Hence, GEMBE provides an alternative platform for total protein assays while maintaining the excellent sensitivity of the optical-based methods. PMID:24648165

  18. Drug-eluting bead therapy in primary and metastatic disease of the liver

    PubMed Central

    Carter, Stewart; Martin II, Robert C G

    2009-01-01

    studies reported length of hospital stay, which averaged 2.3 days per procedure. Mortality was reported as occurring in 10 of 456 (2%) procedures, or 10 of 214 (5%) patients. Conclusions: Drug-eluting bead TACE is becoming more widely utilized in primary and liver-dominant metastatic disease of the liver. Outcomes of success must be expanded beyond response rates because these are not a reliable surrogate for progression-free survival or overall survival. Ongoing clinical trials will further clarify the optimal timing and strategy of this technology. PMID:20495705

  19. Drug-eluting stents and acute myocardial infarction: A lethal combination or friends?

    PubMed Central

    Otsuki, Shuji; Sabaté, Manel

    2014-01-01

    Primary percutaneous coronary intervention is the preferred reperfusion strategy for patients presenting with ST-segment elevation myocardial infarction (STEMI). First generation drug-eluting stents (DES), (sirolimus drug-eluting stents and paclitaxel drug-eluting stents), reduce the risk of restenosis and target vessel revascularization compared to bare metal stents. However, stent thrombosis emerged as a major safety concern with first generation DES. In response to these safety issues, second generation DES were developed with different drugs, improved stent platforms and more biocompatible durable or bioabsorbable polymeric coating. This article presents an overview of safety and efficacy of the first and second generation DES in STEMI. PMID:25276295

  20. Drug eluting biliary stents to decrease stent failure rates: A review of the literature

    PubMed Central

    Shatzel, Joseph; Kim, Jisoo; Sampath, Kartik; Syed, Sharjeel; Saad, Jennifer; Hussain, Zilla H; Mody, Kabir; Pipas, J Marc; Gordon, Stuart; Gardner, Timothy; Rothstein, Richard I

    2016-01-01

    Biliary stenting is clinically effective in relieving both malignant and non-malignant obstructions. However, there are high failure rates associated with tumor ingrowth and epithelial overgrowth as well as internally from biofilm development and subsequent clogging. Within the last decade, the use of prophylactic drug eluting stents as a means to reduce stent failure has been investigated. In this review we provide an overview of the current research on drug eluting biliary stents. While there is limited human trial data regarding the clinical benefit of drug eluting biliary stents in preventing stent obstruction, recent research suggests promise regarding their safety and potential efficacy. PMID:26839648

  1. Drug eluting biliary stents to decrease stent failure rates: A review of the literature.

    PubMed

    Shatzel, Joseph; Kim, Jisoo; Sampath, Kartik; Syed, Sharjeel; Saad, Jennifer; Hussain, Zilla H; Mody, Kabir; Pipas, J Marc; Gordon, Stuart; Gardner, Timothy; Rothstein, Richard I

    2016-01-25

    Biliary stenting is clinically effective in relieving both malignant and non-malignant obstructions. However, there are high failure rates associated with tumor ingrowth and epithelial overgrowth as well as internally from biofilm development and subsequent clogging. Within the last decade, the use of prophylactic drug eluting stents as a means to reduce stent failure has been investigated. In this review we provide an overview of the current research on drug eluting biliary stents. While there is limited human trial data regarding the clinical benefit of drug eluting biliary stents in preventing stent obstruction, recent research suggests promise regarding their safety and potential efficacy. PMID:26839648

  2. A new polymer-free drug-eluting stent with nanocarriers eluting sirolimus from stent-plus-balloon compared with bare-metal stent and with biolimus A9 eluting stent in porcine coronary arteries

    PubMed Central

    Galon, Micheli Z.; Gutierrez, Paulo S.; Sojitra, Prakash; Vyas, Ashwin; Doshi, Manish; Lemos, Pedro A.

    2015-01-01

    Background Permanent polymers in first generation drug-eluting stent (DES) have been imputed to be a possible cause of persistent inflammation, remodeling, malapposition and late stent thrombosis. We aim to describe the in vivo experimental result of a new polymer-free DES eluting sirolimus from stent-plus-balloon (Focus np stent, Envision Scientific) compared with a bare-metal stent (BMS) (Amazonia CroCo, Minvasys) and with a biolimus A9 eluting stent (Biomatrix, Biosensors). Methods In 10 juvenile pigs, 23 coronary stents were implanted in the coronary arteries (8 Amazonia CroCo, 8 Focus np, and 7 Biomatrix). At 28-day follow-up, optical coherence tomography (OCT) and histology were used to evaluate neointimal hyperplasia and healing response. Results According to OCT analysis, Focus np stents had a greater lumen area and less neointimal hyperplasia response than BMS and Biomatrix had. Histomorphometry results showed less neointimal hyperplasia in Focus np than in BMS. Histology showed a higher fibrin deposition in Biomatrix stent compared to Focus np and BMS. Conclusions The new polymer-free DES with sirolimus eluted from stent-plus-balloon demonstrated safety and reduced neointimal proliferation compared with the BMS and Biomatrix stents at 28-day follow-up in this porcine coronary model. This new polymer-free DES is promising and warrants further clinical studies. PMID:25984451

  3. A completely fractured zotarolimus-eluting stent in an aortocoronary saphenous vein bypass graft.

    PubMed

    Venero, Carmelo V; Aligeti, Venkata R; Wortham, Dale C

    2013-01-01

    Drug-eluting stents (DES) have significantly improved the rate of target vessel revascularization in comparison with bare metal stents. DES fracture was not reported in multicenter randomized clinical trials, but several case reports of DES fracture have been published, mostly with sirolimus-eluting stents. DES fracture is associated with stent restenosis and thrombosis. We report a zotarolimus-eluting stent fracture in an aortocoronary saphenous vein graft (SVG) bypass. The patient presented with chest pain and a non-ST-elevation myocardial infarction. He underwent cardiac catheterization that showed a complete fracture of a zotarolimus-eluting stent in the ostium of a sequential SVG to the diagonal and obtuse coronary arteries. His management included coronary angioplasty and retrieval of the proximal fractured segment. We discuss the potential causes for this stent fracture and suggest caution when using a DES in an ostial location of a SVG bypass, especially in a highly mobile vessel. PMID:22553171

  4. Inflammation and impaired wound healing after zotarolimus-eluting stent implantation.

    PubMed

    Yoneda, Shuichi; Abe, Shichiro; Taguchi, Isao; Masawa, Nobuhide; Inoue, Katsumi; Inoue, Teruo

    2012-01-01

    An 86-year-old man died suddenly 5 months after implantation of a zotarolimus-eluting stent. Two zotarolimus-eluting stents were placed to treat a highly calcified diffuse lesion in the proximal-to-mid right coronary artery. The lesion was fully covered by the two stents, and intravascular ultrasound showed complete stent apposition. However, an X-ray at autopsy showed that the proximal stent was fractured. Although we thought that thrombotic occlusion at the fracture site might have caused his sudden death, no thrombus was present. In addition, in the other sites where the stents were optimally dilated, there was stent malapposition and peri-strut inflammation including macrophage infiltration, giant cells, polymer phagocytosis, and neovascularization in the neointima. Even with a second-generation drug-eluting stent, such as the zotarolimus-eluting stent, wound healing may be impaired at the stent-injured vessel site. PMID:22356902

  5. EVALUATION OF POTENTIAL ELUANTS FOR NON-ACID ELUTION OF CESIUM FROM RESORCINOL-FORMALDEHYDE RESIN

    SciTech Connect

    Adu-Wusu, K.; Pennebaker, F.

    2010-12-22

    Small-column ion exchange (SCIX) units installed in high-level waste tanks to remove Cs-137 from highly alkaline salt solutions are among the waste treatment plans in the DOE-complex. Spherical Resorcinol-Formaldehyde (sRF) is the ion exchange resin selected for use in the Hanford Waste Treatment and Immobilization Plant (WTP). It is also the primary ion exchange material under consideration for SCIX at the Hanford site. The elution step of the multi-step ion exchange process is typically done with 0.5 M nitric acid. An acid eluant is a potential hazard in the event of a spill, leak, etc. because the high-level waste tanks are made of carbon steel. Corrosion and associated structural damage may ensue. A study has been conducted to explore non-acid elution as an alternative. Batch contact sorption equilibrium screening tests have been conducted with 36 potential non-acid eluants. The sorption tests involve equilibrating each cesium-containing eluant solution with the sRF resin for 48 hours at 25 C in a shaker oven. In the sorption tests, an eluant is deemed to have a high cesium elution potential if it minimizes cesium sorption onto the sRF resin. The top candidates (based on lowest cesium sorption distribution coefficients) include ammonium carbonate, ammonium carbonate/ammonium hydroxide, ammonium bicarbonate, rubidium carbonate, ammonium acetate, ammonium acetate/ammonium hydroxide, ammonium bicarbonate/ammonium hydroxide, calcium chloride, and magnesium chloride. A select few of the top candidate eluants from the screening tests were subjected to actual sorption (loading) and elution tests to confirm their elution ability. The actual sorption (loading) and elution tests mimicked the typical sRF-cesium ion exchange process (i.e., sorption or loading, caustic wash, water rinse, and elution) via batch contact sorption and quasi column caustic wash/water rinse/elution. The eluants tested included ammonium carbonate, ammonium acetate, calcium acetate, magnesium

  6. Oral Factors Affecting Titanium Elution and Corrosion: An In Vitro Study Using Simulated Body Fluid

    PubMed Central

    Suito, Hideki; Iwawaki, Yuki; Goto, Takaharu; Tomotake, Yoritoki; Ichikawa, Tetsuo

    2013-01-01

    Objectives Ti, which is biocompatible and resistant to corrosion, is widely used for dental implants, particularly in patients allergic to other materials. However, numerous studies have reported on Ti allergy and the in vitro corrosion of Ti. This study investigated the conditions that promote the elution of Ti ions from Ti implants. Methods Specimens of commercially pure Ti, pure nickel, a magnetic alloy, and a gold alloy were tested. Each specimen was immersed in a simulated body fluid (SBF) whose pH value was controlled (2.0, 3.0, 5.0, 7.4, and 9.0) using either hydrochloric or lactic acid. The parameters investigated were the following: duration of immersion, pH of the SBF, contact with a dissimilar metal, and mechanical stimulus. The amounts of Ti ions eluted were measured using a polarized Zeeman atomic absorption spectrophotometer. Results Eluted Ti ions were detected after 24 h (pH of 2.0 and 3.0) and after 48 h (pH of 9.0). However, even after 4 weeks, eluted Ti ions were not detected in SBF solutions with pH values of 5.0 and 7.4. Ti elution was affected by immersion time, pH, acid type, mechanical stimulus, and contact with a dissimilar metal. Elution of Ti ions in a Candida albicans culture medium was observed after 72 h. Significance Elution of Ti ions in the SBF was influenced by its pH and by crevice corrosion. The results of this study elucidate the conditions that lead to the elution of Ti ions in humans, which results in implant corrosion and Ti allergy. PMID:23762461

  7. Effects of ageing on elution behaviour of nitrogenous compounds in disposed wastes from landfill sites.

    PubMed

    Nishio, Takayuki

    2014-01-01

    Comparative studies of elution and cation exchange capacity (CEC) tests were applied to aged and fresh municipal and industrial solid wastes to examine the effects of ageing on the long-term elution behaviour of nitrogen on leachate in municipal and industrial solid waste landfill sites. Nitrogen in the leachate gradually eluted as organic nitrogen, but not upon transformation of organic nitrogen to elutable inorganic nitrogen compounds in the solid waste. Ammonium in the solid waste, retained similar to its interaction with clay minerals in soil, elutes when exposed to leachate by being replaced with highly concentrated cations or loses its positive charge in high pH in the leachate, which percolates down from the upper layer of the disposed waste. The quantity of ammonium adsorbed into the aged wastes through CEC measurement process by replacement with ammonium acetate was higher than that onto the fresh wastes. That difference in quantities can serve as an index of the ability of the solid waste to withhold ammonium in the leachate that percolates down the landfill layer. Those results demonstrate that ammonification of organic nitrogen in the waste is not the crucial step of the elution of nitrogenous compounds into leachate. PMID:25145199

  8. Multiple enzyme purifications from muscle extracts by using affinity-elution-chromatographic procedures.

    PubMed Central

    Scopes, R K

    1977-01-01

    1. Starting with (NH4)2SO4 fractions of muscle extracts, procedures for purifying four to six separate enzymes from each fraction by using affinity-elution-chromatographic techniques are described. 2. Schemes for purifying 12 separate enzymes from rabbit muscle, and eight from chicken muscle extracts, are included. In nearly all cases the overall procedure involves three steps: the initial (NH4)2SO4 fractionation, the ion-exchange chromatography with affinity elution of the enzyme, and gel filtration. The specific activities of the enzymes so purified are comparable with the highest values in the literature. 3. The five schemes described include illustrations of affinity elution of the separate enzymes at different pH values, at different ionic strengths and in combination with conventional gradient elution. They also include stepwise adsorption on columns at different pH values. 4. Separation of two electrophoretically differing forms of phosphoglycerate kinase was achieved by gradient affinity elution from CM-cellulose. The lower-pI form was eluted by a lower concentration of substrate than the higher-pI form. PMID:849261

  9. Nonspecific native elution of proteins and mumps virus in immunoaffinity chromatography.

    PubMed

    Brgles, Marija; Sviben, Dora; Forčić, Dubravko; Halassy, Beata

    2016-05-20

    Immunoaffinity chromatography, based on the antigen-antibody recognition, enables specific purification of any antigen (protein, virus) by its antibody. The problem with immunoaffinity chromatography is the harsh elution conditions required for disrupting strong antigen-antibody interactions, such as low pH buffers, which are often deleterious for the immobilized protein and the protein to be isolated since they can also disrupt the intramolecular forces. Therefore, immunoaffinity chromatography can only be partially used for protein and virus purification. Here we report on a nonspecific elution in immunoaffinity chromatography using native conditions by elution with amino acid solution at physiological pH for which we suppose possible competing mechanism of action. Elution potential of various amino acid solutions was tested using immunoaffinity columns specific for ovalbumin and mumps virus, and protein G affinity column. Results have shown that the most successful elution solutions were those containing imidazole and arginine of high molarity. Imidazole represents aromatic residues readily found at the antigen-antibody interaction surface and arginine is most frequently found on protein surface in general. Therefore, results on their eluting power in immunoaffinity chromatography, which increases with increasing molarity, are in line with the competing mechanism of action. Virus immunoaffinity chromatography resulted in removal on nonviable virus particles, which is important for research and biotechnology purposes. In addition, amino acids are proven stabilizers for proteins and viruses making approach presented in this work a very convenient purification method. PMID:27090389

  10. Size and composition of synthetic calcium sulfate beads influence dissolution and elution rates in vitro.

    PubMed

    Roberts, Randy; McConoughey, Stephen J; Calhoun, Jason H

    2014-05-01

    Treatments of osteomyelitis lag behind bacterial resistance to antibiotics. We tested different-sized calcium sulfate beads and their ability to elute multiple antibiotics in vitro as a possible method to improve the therapeutic delivery in patients. Two sizes of calcium sulfate beads (4.8 and 3.0 mm diameter) that contained vancomycin, tobramycin, or both were dissolved in phosphate-buffered saline, and the rate of dissolution by weight and antibiotic elution by the disc diffusion assay and high-pressure liquid chromatography were measured. The 4.8 mm beads showed significantly higher dissolution rates relative to the 3.0 mm beads (2.3 mg/day vs. 1.3 mg/day). While the vancomycin-loaded 4.8 mm beads eluted for a longer time relative to the 3.0 mm beads (20 days vs. 10 days), the smaller beads had threefold higher elution for the first 2 days, before dropping to near zero elution by day 4. The presence of tobramycin extended the elution of the vancomycin to day 40, which closely matches the recommended 6 weeks to treat orthopedic staphylococcus infections. These data suggest that size and content of the bead are variables that could affect their clinical success, and both could be exploited to tailor treatments of specific infections and injuries. PMID:24155136

  11. Quantitative determination of abacavir (1592U89), a novel nucleoside reverse transcriptase inhibitor, in human plasma using isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection.

    PubMed

    Veldkamp, A I; Sparidans, R W; Hoetelmans, R M; Beijnen, J H

    1999-12-24

    Abacavir is a novel nucleoside reverse transcriptase inhibitor for the treatment of HIV-1 infection. A simple and rapid high-performance liquid chromatographic method for the quantification of abacavir in human plasma suitable for pharmacokinetic research purposes is described. Sample pretreatment consists of protein precipitation with perchloric acid. The supernatant is injected directly into the chromatographic system after centrifugation. The drug is separated from endogenous compounds by isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection at 285 nm. The method has been validated over the range of 20-2000 ng/ml using a volume of 300 microl of plasma. The assay is linear over this concentration range as indicated by the F-test for lack-of-fit. Within- and between-day precisions are less than 7.5% for all quality control samples. The lower limit of quantitation is 20 ng/ml and the recovery of abacavir is 88.1% (+/-1.3%). Frequently coadministered drugs did not interfere with the described methodology. Abacavir is stable in human plasma under various relevant storage conditions, for example when stored for 51 days at -20 degrees C. This validated assay is suited for use in pharmacokinetic studies with abacavir in human plasma and can readily be implemented in the setting of a hospital laboratory for the monitoring of abacavir concentrations. PMID:10676991

  12. Proteome Analyses Using Accurate Mass and Elution Time Peptide Tags with Capillary LC Time-of-Flight Mass Spectrometry

    SciTech Connect

    Strittmatter, Eric F.; Ferguson, Patrick L.; Tang, Keqi; Smith, Richard D.

    2003-09-01

    We describe the application of capillary liquid chromatography (LC) time-of-flight (TOF) mass spectrometric instrumentation for the rapid characterization of microbial proteomes. Previously (Lipton et al. Proc. Natl Acad. Sci. USA, 99, 2002, 11049) the peptides from a series of growth conditions of Deinococcus radiodurans have been characterized using capillary LC MS/MS and accurate mass measurements which are logged in an accurate mass and time (AMT) tag database. Using this AMT tag database, detected peptides can be assigned using measurements obtained on a TOF due to the additional use of elution time data as a constraint. When peptide matches are obtained using AMT tags (i.e. using both constraints) unique matches of a mass spectral peak occurs 88% of the time. Not only are AMT tag matches unique in most cases, the coverage of the proteome is high; {approx}3500 unique peptide AMT tags are found on average per capillary LC run. From the results of the AMT tag database search, {approx}900 ORFs detected using LC-TOFMS, with {approx}500 ORFs covered by at least two AMT tags. These results indicate that AMT databases searches with modest mass and elution time criteria can provide proteomic information for approximately one thousand proteins in a single run of <3 hours. The advantage of this method over using MS/MS based techniques is the large number of identifications that occur in a single experiment as well as the basis for improved quantitation. For MS/MS experiments, the number of peptide identifications is severely restricted because of the time required to dissociate the peptides individually. These results demonstrate the utility of the AMT tag approach using capillary LC-TOF MS instruments, and also show that AMT tags developed using other instrumentation can be effectively utilized.

  13. Simulation of elution profiles in liquid chromatography-I: Gradient elution conditions, and with mismatched injection and mobile phase solvents.

    PubMed

    Jeong, Lena N; Sajulga, Ray; Forte, Steven G; Stoll, Dwight R; Rutan, Sarah C

    2016-07-29

    High-performance liquid chromatography (HPLC) simulators are effective method development tools. The goal of the present work was to design and implement a simple algorithm for simulation of liquid chromatographic separations that allows for characterization of the effect of injection solvent mismatch and injection solvent volume overload. The simulations yield full analyte profiles during solute migration and at elution, which enable a thorough physical understanding of the effects of method variables on chromatographic performance. The Craig counter-current distribution model (the plate model) is used as the basis for simulation, where a local retention factor is assigned for each spatial and temporal element within the simulation. The algorithm, which is an adaptation of an approach originally described by Czok and Guiochon (Ref. [10]), is sufficiently flexible to allow the use of either linear (e.g., Linear Solvent Strength Theory) or non-linear models of solute retention (e.g., Neue-Kuss (Ref. [36])). In this study, both types of models were used, one for simulating separations of a homologous series of alkylbenzenes, and the other for separations of selected amphetamines. The simulation program was validated first by comparison of simulated retention times and peak widths for five amphetamines to predictions obtained using linear solvent strength (LSS) theory, and to results from experimental separations of these compounds. The simulated retention times for the amphetamines agreed within 0.02% and 2.5% compared to theory and experiment, respectively. Secondly, the program was evaluated for simulating the case where there is a compositional mismatch between the mobile phase at the column inlet and the injection solvent (i.e., the sample matrix). This work involved alkylbenzenes, and retention time and peak width predictions from simulations were within 1.5 and 6.0% of experimental values, respectively, even without correction for extra-column dispersion. The

  14. Osmolarity effects on red blood cell elution in sedimentation field-flow fractionation.

    PubMed

    Assidjo, N E; Chianéa, T; Clarot, I; Dreyfuss, M F; Cardot, P J

    1999-07-01

    Field-flow fractionation (FFF) is an analytical technique particularly suitable for the separation, isolation, and characterization of macromolecules and micrometer- or submicrometer-sized particles. This chromatographic-like methodology can modulate the retention of micron-sized species according to an elution mode described to date as "steric hyperlayer". In such a model, differences in sample species size, density, or other physical parameters make particle selective elution possible depending on the configuration and the operating conditions of the FFF system. Elution characteristics of micron-sized particles of biological origin, such as cells, can be modified using media and carrier phases of different osmolarities. In these media, a cells average size, density, and shape are modified. Therefore, systematic studies of a single reference cell population, red blood cells (RBCs), are performed with 2 sedimentation FFF systems using either gravity (GrFFF) or a centrifugational field (SdFFF). However, in all cases, normal erythrocyte in isotonic suspension elutes as a single peak when fractionated in these systems. With carrier phases of different osmolarities, FFF elution characteristics of RBCs are modified. Retention modifications are qualitatively consistent with the "steric-hyperlayer" model. Such systematic studies confirm the key role of size, density, and shape in the elution mode of RBCs in sedimentation FFF for living, micronsized biological species. Using polymers as an analogy, the RBC population is described as highly "polydisperse". However, this definition must be reconsidered depending on the parameters under concern, leading to a matricial concept: multipolydispersity. It is observed that multipolydispersity modifications of a given RBC population are qualitatively correlated to the eluted sample band width. PMID:10422264

  15. An in-vitro evaluation of three types of drug-eluting microspheres loaded with irinotecan.

    PubMed

    Pereira, Philippe L; Plotkin, Stephen; Yu, Renee; Sutter, Allison; Wu, Yue; Sommer, Christof M; Cruise, Gregory M

    2016-10-01

    To compare the mechanical and chemical properties of three commercially available microspheres loaded with irinotecan. LifePearl (200 µm), DC Bead (100-300 µm), and Tandem (100 µm) microspheres were loaded with irinotecan. For loading, elution, and stability determinations, irinotecan concentrations were quantified using validated high-performance liquid chromatography methods. In-vitro elution was performed over 24 h using a USP 4 dissolution apparatus. Diameter measurements were performed using light microscopy. Time in suspension was considered as the time required for the microspheres to vacate 1/3 of the volume. All three microsphere types rapidly loaded irinotecan, with more than 95% loading at 1 h. In-vitro elution of irinotecan was rapid for LifePearl and DC Bead microspheres, with more than 98% elution at 1 h, and delayed for Tandem microspheres, with about 70% elution at 6 h. After loading with irinotecan, the average diameter of LifePearl and DC Bead microspheres was reduced by 9 and 18%, respectively, and was unchanged for Tandem microspheres. All three microsphere types lost 4-6% of the loaded irinotecan almost immediately upon placement in contrast: water and contrast: 5% dextrose, but further losses were minimal over 2 weeks. LifePearl microspheres remained longer in suspension (392±23 s) compared with DC Bead (154±13 s, P<0.001) and Tandem (198±19 s, P<0.001) microspheres. All three microsphere types load irinotecan rapidly. LifePearl and DC Bead microspheres elute irinotecan rapidly. Elution is delayed with Tandem microspheres. LifePearl microspheres show the longest time in suspension. PMID:27416270

  16. The Influence of Irradiation Time and Layer Thickness on Elution of Triethylene Glycol Dimethacrylate from SDR® Bulk-Fill Composite

    PubMed Central

    Jakubowska, Katarzyna; Chlubek, Dariusz; Buczkowska-Radlińska, Jadwiga

    2016-01-01

    Objective. This study aimed to evaluate triethylene glycol dimethacrylate (TEGDMA) elution from SDR bulk-fill composite. Methods. Three groups of samples were prepared, including samples polymerized in a 4 mm layer for 20 s, in a 4 mm layer for 40 s, and in a 2 mm layer for 20 s. Elution of TEGDMA into 100% ethanol, a 75% ethanol/water solution, and distilled water was studied. The TEGDMA concentration was measured using HPLC. Results. The TEGDMA concentration decreased in the following order: 100% ethanol > 75% ethanol > distilled water. Doubling the energy delivered to the 4 mm thick sample caused decrease (p < 0.05) in TEGDMA elution to distilled water. In ethanol solutions, the energy increase had no influence on TEGDMA elution. Decreasing the sample thickness resulted in decrease (p < 0.05) in TEGDMA elution for all the solutions. Conclusions. The concentration of eluted TEGDMA and the elution time were both strongly affected by the hydrophobicity of the solvent. Doubling the energy delivered to the 4 mm thick sample did not decrease the elution of TEGDMA but did decrease the amount of the monomer available to less aggressive solvents. Elution of TEGDMA was also correlated with the exposed sample surface area. Clinical Relevance. Decreasing the SDR layer thickness decreases TEGDMA elution. PMID:27366742

  17. Precision-controlled elution of a 82Sr/82Rb generator for cardiac perfusion imaging with positron emission tomography.

    PubMed

    Klein, R; Adler, A; Beanlands, R S; Dekemp, R A

    2007-02-01

    A rubidium-82 ((82)Rb) elution system is described for use with positron emission tomography. Due to the short half-life of (82)Rb (76 s), the system physics must be modelled precisely to account for transport delay and the associated activity decay and dispersion. Saline flow is switched between a (82)Sr/(82)Rb generator and a bypass line to achieve a constant-activity elution of (82)Rb. Pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control (PCC) algorithm is developed which produces a constant-activity elution within the constraints of long feedback delay and short elution time. The system model parameters are adjusted through a self-tuning algorithm to minimize error versus the requested time-activity profile. The system is self-calibrating with 2.5% repeatability, independent of generator activity and elution flow rate. Accurate 30 s constant-activity elutions of 10-70% of the total generator activity are achieved using both control methods. The combined PWM-PCC method provides significant improvement in precision and accuracy of the requested elution profiles. The (82)Rb elution system produces accurate and reproducible constant-activity elution profiles of (82)Rb activity, independent of parent (82)Sr activity in the generator. More reproducible elution profiles may improve the quality of clinical and research PET perfusion studies using (82)Rb. PMID:17228112

  18. Impact of ultrasonic time on hot water elution of severely biodegraded heavy oil from weathered soils.

    PubMed

    Ji, Guodong; Sui, Xin

    2010-07-15

    An ultrasound-enhanced elution system employing water at a temperature of 70 degrees C was used to remedy weathered soils contaminated with severely biodegraded heavy oil (SBHO). The effect of varying the ultrasonic irradiation time from 0 to 1800 s on the elution of SBHO and three characteristic biomarkers (C(26-34) 17alpha 25-norhopanes, C(26-28) TAS, and C(27-29) MTAS) was analyzed using GC/MS, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Elution of the three biomarkers was closely related to the carbon number of the marker. C(26-34) 17alpha 25-norhopanes and C(26-28) TAS species with higher carbon numbers and C(27-29) MTAS species with lower carbon numbers were more readily eluted using sonication times of 1080-1800 s, while smaller TAS homologs were more readily eluted after sonication times of 0-360 s. SEM images of samples treated for longer periods revealed larger "bare patches" on the soil surface. The results of XRD and energy spectroscopy experiments indicated that ultrasound irradiation for 1080 s negatively affected the deposition of CaCO(3), but overall improved the mineral and chemical compositions of treated soils and removal of SBHO. PMID:20347521

  19. Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

    PubMed

    Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

    2015-02-01

    Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions. PMID:24261406

  20. Establishing conditions for the storage and elution of rabies virus RNA using FTA® cards

    PubMed Central

    SAKAI, Takeo; ISHII, Ayako; SEGAWA, Takao; TAKAGI, Yukihiko; KOBAYASHI, Yuki; ITOU, Takuya

    2014-01-01

    The Flinders Technology Associates filter paper cards (FTA® cards) can be used to store nucleic acid from various samples and are easily portable. However, RNA is physicochemically unstable compared with DNA, and appropriate methods have not been established for storage and extraction of RNA from FTA® cards. The present study investigated the optimum conditions for storage and elution of viral RNA (vRNA) using rabies virus (RABV) applied to FTA® cards. When TE buffer was used, the elution rates of vRNA increased with the length of the elution time. When the cards were stored at −80°C or −20°C, vRNA was stable over 3 months. Degradation of vRNAs occurred following storage at 4°C and room temperature, suggesting that RNA should be extracted from cards as soon as possible if no freezer is available. When we tried to amplify vRNA from RABV-infected animal brains applied to FTA® cards and stored at −80°C for 6 months, we did not detect any amplified products with the primer set for 964 bp of RABV N gene. However, we were able to detect amplified products by increasing the elution time of vRNA from FTA® cards from 30 min to 24 hr or by changing the primer sets to amplify 290 bp of N gene. Thus, we recommend extending the elution time for damaged or low concentration samples in FTA® cards. PMID:25648208

  1. Contrasting Effects of Physical Wear on Elution of Two Antibiotics from Orthopedic Cement

    PubMed Central

    Dodds, S.; Akid, R.; Stephenson, J.; Nichol, T.; Banerjee, R. D.; Stockley, I.; Townsend, R.

    2012-01-01

    The use of antibiotics as a supplement to bone cement for the purposes of providing a local release of antibiotics is common practice in arthroplasty surgery and the kinetics of elution of the antibiotics in such systems have been investigated previously. However, in these previous studies no account was taken of the potential effects that wear may have on the elution kinetics of the antibiotic. Here, we have modified an existing wear testing rig to allow the simultaneous study of the elution kinetics of bone cement samples containing antibiotics being subjected to immersion only and immersion and conjoint wear. The results show contrasting effects with two commonly used antibiotics. Bone cement containing daptomycin showed no substantial change in antibiotic elution due to wear, while cement containing gentamicin (the most commonly used antibiotic in this application) in contrast demonstrated a substantial reduction in the rate of antibiotic elution when wear was applied. Scanning electron microscopy revealed a possible explanation for these diverse results, due to wear-induced “sealing” of the surface in conjunction with the crystal morphology of the antibiotic. PMID:22155831

  2. Comparison between sirolimus- and paclitaxel-eluting stent in T-cell subsets redistribution.

    PubMed

    Sardella, Gennaro; De Luca, Leonardo; Di Roma, Angelo; De Persio, Giovanni; Conti, Giulia; Paroli, Marino; Fedele, Francesco

    2006-02-15

    We sought to investigate the effects of 2 different coronary drug-eluting stents on the distribution of central or effector memory T cells circulating in the coronary sinus of patients with coronary artery disease who underwent percutaneous coronary revascularization. We randomly assigned 43 patients (mean age 65.4 +/- 4.3 years; 34 men) presenting with stable coronary disease and angiographically proved stenosis of the left anterior descending artery to treatment with sirolimus- or paclitaxel-eluting stents. Heparinized blood samples were obtained from the coronary sinus before and 20 minutes after stent implantation. Analysis of surface phenotype was performed by 4-color flow cytometry, and data are expressed as the percentage of positive cells. The percentages of CD8+ and CD4+ effector memory T cells, as defined by the CD3+CD45RO+CD27- phenotype, were significantly reduced in patients who received a sirolimus-eluting stent compared with the basal values. Conversely, the percentages of CD8+, but not CD4+, central memory T cells (CD3+CD45RO+CD27+) were increased in the same treatment group after the revascularization procedure. No changes in the percentages of memory T-cell populations in the paclitaxel-eluting stent group were observed. These findings show that sirolimus-eluting stents rapidly induced a redistribution of memory T lymphocytes, with a significant decrease of proinflammatory effector memory T cells circulating within the coronary sinus. PMID:16461044

  3. A novel platinum chromium everolimus-eluting stent for the treatment of coronary artery disease

    PubMed Central

    Bennett, Johan; Dubois, Christophe

    2013-01-01

    The development of coronary stents represents a major step forward in the treatment of obstructive coronary artery disease since the introduction of percutaneous coronary intervention. The initial enthusiasm for bare metal stents was, however, tempered by a significant incidence of in-stent restenosis, the manifestation of excessive neointima hyperplasia within the stented vessel segment, ultimately leading to target vessel revascularization. Later, drug-eluting stents, with controlled local release of antiproliferative agents, consistently reduced this need for repeat revascularization. In turn, the long-term safety of first-generation drug-eluting stents was brought into question with the observation of an increased incidence of late stent thrombosis, often presenting as myocardial infarction or sudden death. Since then, new drugs, polymers, and platforms for drug elution have been developed to improve stent safety and preserve efficacy. Development of a novel platinum chromium alloy with high radial strength and high radiopacity has enabled the design of a new, thin-strut, flexible, and highly trackable stent platform, while simultaneously improving stent visibility. Significant advances in polymer coating, serving as a drug carrier on the stent surface, and in antiproliferative agent technology have further improved the safety and clinical performance of newer-generation drug-eluting stents. This review will provide an overview of the novel platinum chromium everolimus-eluting stents that are currently available. The clinical data from major clinical trials with these devices will be summarized and put into perspective. PMID:23818756

  4. In vitro tobramycin elution analysis from a novel beta-tricalcium phosphate-silicate-xerogel biodegradable drug-delivery system.

    PubMed

    DiCicco, Michael; Goldfinger, Aaron; Guirand, Felix; Abdullah, Aquill; Jansen, Susan A

    2004-07-15

    This in vitro research analyzed local tobramycin elution characteristics from a novel, biodegradable drug delivery system, consisting of a beta-TCP bone substitute, VITOSS trade mark, encapsulated with silicate xerogel prepared by the sol-gel process. Tobramycin elution from silicate-xerogel-encapsulated VITOSS was compared directly with non-silicate-xerogel-encapsulated VITOSS to assess whether xerogels are effective in delivering greater tobramycin quantities in a controllable, sustained manner crucial for microbial inhibition. Tobramycin elution characteristics indicate an initial release maximum during the first 24 h that diminishes gradually several days after impregnation. The copious tobramycin quantity eluted from the VITOSS/silicate-xerogel systems is attributed to various factors: the intrinsic ultraporosity and hydrophilicity of VITOSS, the ability of tobramycin to completely dissolve in aqueous media, tobramycin complexation with highly polar SO(4) (2-) salts that further assist dissolution, and ionic exchanges between VITOSS and the environment. Silicate-xerogel-encapsulated VITOSS eluted 60.65 and 61.31% of impregnated tobramycin, whereas non-silicate-xerogel-encapsulated VITOSS eluted approximately one-third less impregnated tobramycin, at 21.53 and 23.60%. These results suggest that silicate xerogel optimizes tobramycin elution because of its apparent biodegradability. This mechanism occurs through xerogel superficial acidic sites undergoing exchanges with various ions present in the leaching buffer. Tobramycin elution kinetics were evaluated, and demonstrate that first-order elution rate constants are considerably less when silicate xerogels are employed, following a more uniform exponential decay-type mechanism, thus bolstering controlled release. Overall, tobramycin elution rates adhere to linear-type Higuchi release profiles. Elution rate constants are initially first order, and taper into zero-order elution kinetics in the latter stages of

  5. Reduction of Solvent Effect in Reverse Phase Gradient Elution LC-ICP-MS

    SciTech Connect

    Patrick Allen Sullivan

    2005-12-17

    %-35% (simulated) and 8%-32% (actual). Quadrupole (low resolution) and sector field (high resolution) ICP-MS instrumentation were utilized in these studies. Once an AIS pair is determined, quantification studies can be performed. First, an analysis is performed by adding both elements of the AIS pair post-column while performing the gradient elution without sample injection. A comparison of the ratio of the measured intensities to the atomic ratio of the two standards is used to determine a correction factor that can be used to account for the matrix effects caused by the mobile phase. Then, organic and/or biological molecules containing one of the two elements in the AIS pair are injected into the LC column. A gradient method is used to vary the methanol-water mixture in the mobile phase and to separate out the compounds in a given sample. A standard solution of the second ion in the AIS pair is added continuously post-column. By comparing the ratio of the measured intensities to the atomic ratio of the eluting compound and internal standard, the concentration of the injected compound can be determined.

  6. Drug-eluting stents: role of stent design, delivery vehicle, and drug selection.

    PubMed

    Rodgers, Campbell D K

    2002-01-01

    Increasing focus has recently been directed toward the different parameters of drug-eluting stents-stent design, delivery-vehicle materials, and drug properties-and the manner in which each of these elements may affect the function of the stents. Several specific characteristics of design may affect restenosis, although design optimization often presents a choice between acute procedural success and long-term biological stability. The influence of design parameters such as strut thickness and cell configuration is described. Polymer material has frequently been used to coat drug-eluting stents, although some agents, such as paclitaxel, can be attached directly to the stent's surface, obviating the need for a polymer layer. The properties of agents used in drug-eluting stents and how those properties affect delivery and long-term outcome are discussed, as is the influence of the disease state of the target vessel on stent safety and efficacy. PMID:12478230

  7. Modeling smooth muscle cell proliferation of coronary artery expanded with a drug eluting stent

    NASA Astrophysics Data System (ADS)

    Lyu, Suping

    2010-03-01

    The drug eluting coronary stent is for the treatment of narrowed coronary artery. A high strength balloon is used to open the narrowed vessel and leave behind a tiny metal mesh, or stent, to mechanically prevent the vessel from re-narrowing and biologically slow down proliferation of the smooth muscle cells. However, the drug eluting stents that had better performance also more seriously prevented the healing processes of the vessels, which could cause serious thrombotic reactions. In this study, we assume the healing process is controlled by proper proliferation of smooth cells. We also assume that the inflammation reactions and mechanical traction drive the smooth muscle cells to proliferate while the drug loaded in the stents drives the processes at the opposite direction. Numerical calculation was applied to the system. The drug distribution and elution durations, inflammation reactions and mechanical traction were discussed.

  8. Some design considerations for polymer-free drug-eluting stents: a mathematical approach.

    PubMed

    McGinty, Sean; Vo, Tuoi T N; Meere, Martin; McKee, Sean; McCormick, Christopher

    2015-05-01

    In this paper we provide the first model of drug elution from polymer-free arterial drug-eluting stents. The generalised model is capable of predicting drug release from a number of polymer-free systems including those that exhibit nanoporous, nanotubular and smooth surfaces. We derive analytical solutions which allow us to easily determine the important parameters that control drug release. Drug release profiles are provided, and we offer design recommendations so that the release profile may be tailored to achieve the desired outcome. The models presented here are not specific to drug-eluting stents and may also be applied to other biomedical implants that use nanoporous surfaces to release a drug. PMID:25712386

  9. Controversies in the use & implementation of drug-eluting stent technology

    PubMed Central

    Itagaki, Brandon K.; Brar, Somjot S.

    2012-01-01

    The introduction of drug eluting stents has resulted in dramatic reductions in the rates of restenosis and the need for repeat revascularization. In the last several years, concern has been raised regarding the long-term safety of this technology, particularly in the area of late restenosis and stent thrombosis. The development of newer anti-restenotic drug coatings, biodegradable polymers and even completely bioabsorbable stents offer the potential to address these limitations. Additional questions that have recently come to the forefront include the optimal duration of dual antiplatelet therapy, the use of platelet reactivity assays and genetic testing and drug eluting stent use in the treatment of acute myocardial infarction. This article will attempt to address these and other areas of controversy in the use and implementation of drug eluting stents. PMID:23391788

  10. The elution of certain protein affinity tags with millimolar concentrations of diclofenac.

    PubMed

    Baliova, Martina; Juhasova, Anna; Jursky, Frantisek

    2015-12-01

    Diclofenac (2-[(2, 6-dichlorophenyl)amino] benzeneacetic acid) is a sparingly soluble, nonsteroidal anti-inflammatory drug therapeutically acting at low micromolar concentrations. In pH range from 8 to 11, its aqueous solubility can be increased up to 200 times by the presence of counter ions such as sodium. Our protein interaction studies revealed that a millimolar concentration of sodium diclofenac is able to elute glutathione S-transferase (GST), cellulose binding protein (CBD), and maltose binding protein (MBP) but not histidine-tagged or PDZ-tagged proteins from their affinity resins. The elution efficiency of diclofenac is comparable with the eluting agents normally used at similar concentrations. Native gel electrophoresis of sodium diclofenac-treated proteins showed that the interaction is non-covalent and non-denaturing. These results suggest that sodium diclofenac, in addition to its pharmaceutical applications, can also be exploited as a lead for the development of new proteomics reagents. PMID:26551210

  11. Alternate Methods for Eluting Cesium from Spherical Resorcinol-Formaldehyde Resin

    SciTech Connect

    Taylor, Paul Allen; Johnson, Heather Lauren

    2009-02-01

    A small-column ion exchange (SCIX) system has been proposed for removing cesium from the supernate and dissolved salt solutions in the high-level-waste tanks at the Savannah River Site (SRS). The SCIX system could use either crystalline silicotitanate (CST), an inorganic, non-regenerable sorbent, or spherical resorcinol-formaldehyde (RF), a new regenerable resin, to remove cesium from the waste solutions. The baseline method for eluting the cesium from the RF resin uses 15 bed volumes (BV) of 0.5 M nitric acid (HNO{sub 3}). The nitric acid eluate, containing the radioactive cesium, would be combined with the sludge from the waste tanks and would be converted into glass at the Defense Waste Processing Facility (DWPF) at SRS. The amount of nitric acid that would be used to elute the RF resin, using the current elution protocol, exceeds the capacity of DWPF to destroy the nitrate ions and maintain the required chemical reducing environment in the glass melt. Installing a denitration evaporator at SRS is technically feasible but would add considerable cost to the project. Alternate methods for eluting the resin have been tested, including using lower concentrations of nitric acid, other acids, and changing the flow regimes. About 4 BV of 0.5 M HNO{sub 3} are required to remove the sodium (titrate the resin) and most of the cesium from the resin, so the bulk of the acid used for the baseline elution method removes a very small quantity of cesium from the resin. A summary of the elution methods that have been tested are listed.

  12. Improved blood compatibility of rapamycin-eluting stent by incorporating curcumin.

    PubMed

    Pan, C J; Tang, J J; Shao, Z Y; Wang, J; Huang, N

    2007-09-01

    This paper dealt with improving the blood compatibility of the rapamycin-eluting stent by incorporating curcumin. The rapamycin- and rapamycin/curcumin-loaded PLGA (poly(d,l-lactic acid-co-glycolic acid)) coatings were fabricated onto the surface of the stainless steel stents using an ultrasonic atomization spray method. The structure of the coating films was characterized by Fourier transform infrared spectroscopy (FTIR). The optical microscopy and scanning electron microscopy (SEM) images of the drug-eluting stents indicated that the surface of all drug-eluting stents was very smooth and uniform, and there were not webbings and "bridges" between struts. There were not any cracks and delaminations on stent surface after expanded by the angioplasty balloon. The in vitro platelet adhesion and activation were investigated by static platelet adhesion test and GMP140 (P-selection), respectively. The clotting time was examined by activated partially prothromplastin time (APTT) test. The fibrinogen adsorption on the drug-loaded PLGA films was evaluated by enzyme-linked immunosorbent assay (ELISA). All obtained data showed that incorporating curcumin in rapamycin-loaded PLGA coating can significantly decrease platelet adhesion and activation, prolong APTT clotting time as well as decrease the fibrinogen adsorption. All results indicated that incorporating curcumin in rapamycin-eluting coating obviously improve the blood compatibility of rapamycin-eluting stents. It was suggested that it may be possible to develop a drug-eluting stent which had the characteristics of not only good anti-proliferation but also improved anticoagulation. PMID:17540543

  13. Medicare and Private Insurance Variations in New Medical Technology: The Case of Drug Eluting Stents

    PubMed Central

    Bayindir, Esra Eren; Mandic, Pinar Karaca

    2016-01-01

    Importance Little is known about the geographic and hospital variations of the new medical technologies in Medicare. Even less is known about these variations for the privately insured. Objective To examine geographic and hospital variations in the diffusion of drug eluting stents, comparing Medicare and privately insured populations. Design Retrospective analyses of discharges from the State Inpatient Databases for 11 states (2004–2005) supplemented with data on hospital characteristics from the American Hospital Association Annual Survey. Setting/participants Study sample included discharges with percutaneous coronary intervention (PCI) procedures that involved a cardiac stent. Exposure Insurance type: Medicare versus private insurance. Main outcome Use of a drug eluting stent during the PCI was our outcome variable. We estimated linear probability models at the discharge level that related our outcome variable to patient and hospital characteristics separately for Medicare and private insurance. To examine variations across hospital referral regions (HRRs) and across hospitals, our models included HRR and hospital indicators respectively. Results Our analysis included 390,649 records (237,991 Medicare, 152,658 private insurance). We found large HRR variations in the use of drug eluting stents in 2004 for both payer types, the year after drug eluting stents were approved (adjusted CoV: 0.35 (Medicare); 0.24 (Private Insurance)). We also found large hospital variations in 2004 (adjusted CoV: 0.32 (Medicare); 0.29 (Private Insurance)). Between 2004 and 2005, adjusted HRR and hospital variations decreased across both payer types, suggesting that practice styles converged as the drug eluting stents diffused and became more common. Finally, adjusted drug eluting stent rates were highly correlated both at the HRR and hospital level across payer types. Conclusion Our findings are consistent with the hypothesis that private insurance closely follows the lead of

  14. Drug-eluting stents in the management of peripheral arterial disease

    PubMed Central

    Bosiers, Marc; Cagiannos, Catherine; Deloose, Koen; Verbist, Jürgen; Peeters, Patrick

    2008-01-01

    Since major meta-analyses of randomized controlled trials in interventional cardiology showed the potential of drug-eluting stents in decreasing restenosis and reintervention rates after coronary artery stenting, one of the next steps in the treatment of arterial occlusive disease is the transfer of the active coating technology towards peripheral arterial interventions. In this manuscript, we aim to provide a literature overview on available peripheral (lower limb, renal, and supra-aortic) drug-eluting stent applications, debate the cost implications, and give recommendations for future treatment strategies. PMID:18827906

  15. A case of coronary rupture and pseudoaneurysm formation after fracture of implanted paclitaxel-eluting stents.

    PubMed

    Kawai, Yasuyuki; Kitayama, Michihiko; Akao, Hironobu; Motoyama, Atsushi; Tsuchiya, Taketsugu; Kajinami, Kouji

    2016-07-01

    A 48-year-old man who had undergone implantation of two paclitaxel-eluting stents (PESs) at the right coronary artery was admitted to our hospital with progressive dyspnea. In the coronary care unit, he developed cardiogenic shock due to cardiac tamponade treated by pericardiocentesis. A coronary angiogram showed a large pseudoaneurysm at the site of the previously implanted stents, suggesting coronary rupture due to implanted stent fracture. The pseudoaneurysm was completely sealed by polytetrafluoroethylene-covered stent implantation. Although this case is very rare, coronary rupture by stent fracture should be considered when cardiac tamponade occurs after drug-eluting stent implantation, especially PES. PMID:25998891

  16. Involvement of COX-2 in nickel elution from a wire implanted subcutaneously in mice.

    PubMed

    Sato, Taiki; Kishimoto, Yu; Asakawa, Sanki; Mizuno, Natsumi; Hiratsuka, Masahiro; Hirasawa, Noriyasu

    2016-07-01

    Many types of medical alloys include nickel (Ni), and the elution of Ni ions from these materials causes toxicities and inflammation. We have previously reported that inflammation enhances Ni elution, although the molecular mechanisms underlying this effect remain unclear. In this study, we investigated how inflammatory responses enhanced Ni elution in a wire-implantation mouse model. Subcutaneous implantation of Ni wire induced the expression of cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) mRNA in the surrounding tissues. Immunostaining analysis showed that cells expressing COX-2 were mainly fibroblast-like cells 8h after implantation of a Ni wire, but were mainly infiltrated leukocytes at 24h. NiCl2 induced the expression of COX-2 mRNA in primary fibroblasts, neutrophils, RAW 264 cells, and THP-1 cells, indicating that Ni ions can induce COX-2 expression in various types of cells. The elution of Ni ions from the implanted Ni wire at 8h was reduced by dexamethasone (Dex), indomethacin (Ind), or celecoxib (Cel) treatment. Ni wire implantation induced an increase in mRNA levels for anaerobic glycolytic pathway components glucose transporter 1 (GLUT1), hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), and monocarboxylate transporter 4 (MCT4); the expression of these genes was also inhibited by Dex, Ind, and Cel. In primary fibroblasts, the expression of these mRNAs and the production of lactate were induced by NiCl2 and further potentiated by PGE2. Furthermore, Ni wire-induced infiltration of inflammatory leukocytes was significantly reduced by Dex, Ind, or Cel. Depletion of neutrophils with a specific antibody caused reduction of both leukocyte infiltration and Ni elution. These results indicate that Ni ions eluted from wire induced COX-2 expression, which further promoted elution of Ni ions by increasing lactate production and leukocyte infiltration. Since COX inhibitors and Dex reduced the elution of Ni ions, these drugs may be

  17. Two Cases of Immediate Stent Fracture after Zotarolimus-Eluting Stent Implantation

    PubMed Central

    Lee, Pil Hyung; Lee, Seung-Whan; Lee, Jong-Young; Kim, Young-Hak; Lee, Cheol Whan; Park, Duk-Woo; Park, Seong-Wook

    2015-01-01

    Drug-eluting stent (DES) implantation is currently the standard treatment for various types of coronary artery disease. However, previous reports indicate that stent fractures, which usually occur after a period of time from the initial DES implantation, have increased during the DES era; stent fractures can contribute to unfavorable events such as in-stent restenosis and stent thrombosis. In our present report, we describe two cases of zotarolimus-eluting stent fracture: one that was detected six hours after implementation, and the other case that was detected immediately after deployment. Both anatomical and technical risk factors contributed to these unusual cases of immediate stent fracture. PMID:25653706

  18. Paclitaxel Drug-Eluting Stents in Peripheral Arterial Disease: A Health Technology Assessment

    PubMed Central

    2015-01-01

    Background Peripheral arterial disease is a condition in which atherosclerotic plaques partially or completely block blood flow to the legs. Although percutaneous transluminal angioplasty and metallic stenting have high immediate success rates in treating peripheral arterial disease, long-term patency and restenosis rates in long and complex lesions remain unsatisfactory. Objective The objective of this analysis was to evaluate the clinical effectiveness, safety, cost-effectiveness and budget impact of Zilver paclitaxel self-expanding drug-eluting stents for the treatment of de novo or restenotic lesions in above-the-knee peripheral arterial disease. Data Sources Literature searches were performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid Embase, EBSCO Cumulative Index to Nursing & Allied Health Literature (CINAHL), and EBM Reviews. For the economic review, a search filter was applied to limit search results to economics-related literature. Data sources for the budget impact analysis included expert opinion, published literature, and Ontario administrative data. Review Methods Systematic reviews, meta-analyses, randomized controlled trials, and observational studies were included in the clinical effectiveness review, and full economic evaluations were included in the economic literature review. Studies were included if they examined the effect of Zilver paclitaxel drug-eluting stents in de novo or restenotic lesions in above-the-knee arteries. For the budget impact analysis, 3 scenarios were constructed based on different assumptions. Results One randomized controlled trial reported a significantly higher patency rate with Zilver paclitaxel drug-eluting stents for lesions ≤ 14 cm than with angioplasty or bare metal stents. One observational study showed no difference in patency rates between Zilver paclitaxel drug-eluting stents and paclitaxel drug-coated balloons. Zilver paclitaxel drug-eluting stents were associated with

  19. Clopidogrel discontinuation within the first year after coronary drug-eluting stent implantation: an observational study

    PubMed Central

    2014-01-01

    Background The impact of adherence to the recommended duration of dual antiplatelet therapy after first generation drug-eluting stent implantation is difficult to assess in real-world settings and limited data are available. Methods We followed 4,154 patients treated with coronary drug-eluting stents in Western Denmark for 1 year and obtained data on redeemed clopidogrel prescriptions and major adverse cardiovascular events (MACE, i.e., cardiac death, myocardial infarction, or stent thrombosis) from medical databases. Results Discontinuation of clopidogrel within the first 3 months after stent implantation was associated with a significantly increased rate of MACE at 1-year follow-up (hazard ratio (HR) 2.06; 95% confidence interval (CI): 1.08-3.93). Discontinuation 3-6 months (HR 1.29; 95% CI: 0.70-2.41) and 6-12 months (HR 1.29; 95% CI: 0.54-3.07) after stent implantation were associated with smaller, not statistically significant, increases in MACE rates. Among patients who discontinued clopidogrel, MACE rates were highest within the first 2 months after discontinuation. Conclusions Discontinuation of clopidogrel was associated with an increased rate of MACE among patients treated with drug-eluting stents. The increase was statistically significant within the first 3 months after drug-eluting stent implantation but not after 3 to 12 months. PMID:25125079

  20. ADSORPTION OF ENTEROVIRUSES TO SOIL CORES AND THEIR SUBSEQUENT ELUTION BY ARTIFICIAL RAINWATER

    EPA Science Inventory

    The adsorption and elution of a variety of human enteroviruses in a highly permeable, sandy soil was studied by using cores (43 by 125 mm) collected from an operating recharge basin on Long Island. Viruses studied included field and reference strains of polioviruses types 1 and 3...

  1. Selection of the Optimum Electrospray Voltage for Gradient Elution LC-MS Measurements

    SciTech Connect

    Marginean, Ioan; Kelly, Ryan T.; Moore, Ronald J.; Prior, David C.; Lamarche, Brian L.; Tang, Keqi; Smith, Richard D.

    2009-04-01

    Changes in liquid composition during gradient elution liquid chromatography (LC) and mass spectrometry (MS) analyses affect the electrospray operation. To establish methodologies for judicious selection of the electrospray voltage, we monitored in real-time the effect of the LC gradient on the spray current. The optimum range of the electrospray voltage shifted to lower values as the concentration of organic solvent in the eluent increased during reversed-phase LC analyses. These results provided the means to rationally select the voltage that ensured successful electrospray operation throughout gradient elution LC-MS experiments. A small run-to-run drift in the spray current was observed for electrosprays operated at constant voltage. This could be the result of fouling or degradation of the electrospray emitter, which affected the electric field driving the electrospray. Algorithms using feedback from spray current measurements to maintain the electrospray voltage within the optimum operating range throughout gradient elution LC-MS were evaluated. The electrospray operation with voltage regulation and at constant, judiciously selected voltage during gradient elution LC-MS measurements produced data with similar reproducibility.

  2. A comparison of two methods of eluting insect DNA from Flinders Technology Associates Cards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flinders Technology Associates (FTA) technology lyses cells and stabilizes DNA for room-temperature storage in a single step but it has been infrequently used with arthropods. One possible reason is the paucity of quick and inexpensive protocols to subsequently elute the DNA from the card matrix. Th...

  3. A bioengineered drug-Eluting scaffold accelerated cutaneous wound healing In diabetic mice.

    PubMed

    Yin, Hao; Ding, Guoshan; Shi, Xiaoming; Guo, Wenyuan; Ni, Zhijia; Fu, Hong; Fu, Zhiren

    2016-09-01

    Hyperglycemia in diabetic patients can greatly hinder the wound healing process. In this study we investigated if the engagement of F4/80(+) murine macrophages could accelerate the cutaneous wound healing in streptozotocin induced diabetic mice. To facilitate the engagement of macrophages, we engineered a drug-eluting electrospun scaffold with a payload of monocyte chemoattractant protein-1 (MCP-1). MCP-1 could be readily released from the scaffold within 3 days. The electrospun scaffold showed no cytotoxic effects on human keratinocytes in vitro. Full-thickness excisional cutaneous wound was created in diabetic mice. The wound fully recovered within 10 days in mice treated with the drug-eluting scaffold. In contrast, the wound took 14 days to fully recover in control groups. The use of drug-eluting scaffold also improved the re-epithelialization. Furthermore, we observed a larger population of F4/80(+) macrophages in the wound bed of mice treated with drug-eluting scaffolds on day 3. This marked increase of macrophages in the wound bed could have contributed to the accelerated wound healing. Our study shed new light on an immuno-engineering solution for wound healing management in diabetic patients. PMID:27187186

  4. Gene Expression Pattern after Insertion of Dexamethasone-Eluting Electrode into the Guinea Pig Cochlea

    PubMed Central

    Mugridge, Kenneth; Oguchi, Tomohiro; Hashimoto, Shigenari; Suzuki, Nobuyoshi; Iwasaki, Satoshi; Jolly, Claude; Usami, Shin-ichi

    2014-01-01

    A cochlear implant is an indispensable apparatus for a profound hearing loss patient. But insertion of the electrode entails a great deal of stress to the cochlea, and may cause irreversible damage to hair cells and related nerve structure. Although damage prevention effects of dexamethasone have been reported, long-term administration is difficult. In this study, we used a dexamethasone-eluting electrode in the guinea pig cochlea, and compared the gene expression after 7 days insertion with that of a normal electrode and non-surgically treated control by microarray. 40 genes were up-regulated 2-fold or more in the normal electrode group compared to the non-surgically treated group. Most of the up-regulated genes were associated with immune response and inflammation. In the dexamethasone-eluting group, compared to the normal electrode group, 7 of the 40 genes were further up-regulated, while 12 of them were down-regulated and there was a tendency to return to the non-surgical condition. 9 genes were down-regulated 2-fold or less with normal electrode insertion, and 4 of the 9 tended to return to the non-surgical condition in the dexamethasone-eluting group. These genes are certainly involved in the maintenance of the physiological functions of the cochlea. Our results indicate that the dexamethasone-eluting electrode will have an effect on the normalization of homeostasis in the cochlea. PMID:25329543

  5. Fiscal year 1996 laboratory scale studies of cesium elution in tank 8D-1

    SciTech Connect

    Russell, R.L.; Patello, G.K.; Sills, J.A.

    1996-09-01

    This report details work performed as part of the West Valley Support Project (WVSP) by Pacific Northwest National Laboratory (PNNL). This work is intended to support residual waste removal during high-level waste (HLW) tank stabilization activities to be performed by the West valley Demonstration Project (WVDP). The HLW originated from a now inactive commercial nuclear fuel-reprocessing plant at West Valley, New York. It is stored in a carbon-steel tank designated 8D-2. Cesium-loaded zeolite was generated by a supernatant decontamination process involving ion exchange. The exchange columns and the spent zeolite are stored in a carbon-steel tank designated 8D-1. During the vitrification phase of the WVDP waste remediation, and estimated 95 percent of the zeolite will be transferred from tank 8D-1 to tank 8D- 2. The remaining cesium-loaded zeolite will require treatment to remove the highly radioactive cesium. This report summarizes the findings of laboratory experiments. The primary objectives of these experiments were: to refine the optimum process conditions for use of oxalic acid to elute cesium from zeolite; minimize iron dissolution during cesium elution; investigation of the effect of neutralization on cesium elution; determination of effects of zeolite particle size on cesium elution; and determine if aluminum can be used as an indicator for cesium in solution.

  6. Elution of zinc in dust discharged from electric arc furnace in carbonic acid solution

    NASA Astrophysics Data System (ADS)

    Yokoyama, S.; Sasaki, T.; Sasano, J.; Izaki, M.

    2012-03-01

    The dust discharged from an electric arc furnace (EAF) is a valuable resource of zinc. As a fundamental study of extraction of zinc, iron and chlorine in the EAF dust, the elution behavior of them in carbonic acid solution was studied. The influence of the weight of the EAF dust on the elution behavior was examined in this study. Experiment was carried out putting the EAF dust from 1 g to 200 g in weight into 1 L of water that was introduced by CO2. Generally, the pH in the aqueous solution increased with an increase in weight of the additive EAF dust. Maximums of the eluted concentrations of zinc and chloride ion increased with an increase in the weight of the additive EAF dust whereas the extraction ratios of both of them decreased with an increase in the weight of the additive EAF dust. Iron in the EAF dust remained in the dust without elution. The limit of extraction of zinc from the EAF dust to water was given by the solubilities of ZnFe2O4 and ZnO expressed by eq. (6) and eq. (9) respectively.

  7. A new mixed-mode model for interpreting and predicting protein elution during isoelectric chromatofocusing.

    PubMed

    Choy, Derek Y C; Creagh, A Louise; von Lieres, Eric; Haynes, Charles

    2014-05-01

    Experimental data are combined with classic theories describing electrolytes in solution and at surfaces to define the primary mechanisms influencing protein retention and elution during isoelectric chromatofocusing (ICF) of proteins and protein mixtures. Those fundamental findings are used to derive a new model to understand and predict elution times of proteins during ICF. The model uses a modified form of the steric mass action (SMA) isotherm to account for both ion exchange and isoelectric focusing contributions to protein partitioning. The dependence of partitioning on pH is accounted for through the characteristic charge parameter m of the SMA isotherm and the application of Gouy-Chapman theory to define the dependence of the equilibrium binding constant Kbi on both m and ionic strength. Finally, the effects of changes in matrix surface pH on protein retention are quantified through a Donnan equilibrium type model. By accounting for isoelectric focusing, ion binding and exchange, and surface pH contributions to protein retention and elution, the model is shown to accurately capture the dependence of protein elution times on column operating conditions. PMID:24293057

  8. 40 CFR 799.6784 - TSCA water solubility: Column elution method; shake flask method.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false TSCA water solubility: Column elution... AND MIXTURE TESTING REQUIREMENTS Product Properties Test Guidelines § 799.6784 TSCA water solubility... here may not yet be optimal. This method is intended for material with solubilities below...

  9. 40 CFR 799.6784 - TSCA water solubility: Column elution method; shake flask method.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 32 2014-07-01 2014-07-01 false TSCA water solubility: Column elution... AND MIXTURE TESTING REQUIREMENTS Product Properties Test Guidelines § 799.6784 TSCA water solubility... here may not yet be optimal. This method is intended for material with solubilities below...

  10. 40 CFR 799.6784 - TSCA water solubility: Column elution method; shake flask method.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 33 2012-07-01 2012-07-01 false TSCA water solubility: Column elution... AND MIXTURE TESTING REQUIREMENTS Product Properties Test Guidelines § 799.6784 TSCA water solubility... here may not yet be optimal. This method is intended for material with solubilities below...

  11. AN ALTERNATIVE ELUENT TO BEEF EXTRACT FOR ELUTING POLIOVIRUS FROM ELECTROPOSITIVE FILTERS

    EPA Science Inventory

    Traditional methods for enteric virus removal from waters involve filtering the water through a positively charged filter followed by elution with beef extract, second step concentration by flocculation, and assay in cell culture. Two of the problems associated with this method ...

  12. Very late sirolimus-eluting stent displaced fracture in the mid-left anterior descending artery.

    PubMed

    Rahman, Nasir; Dhakam, Sajid; Kazmi, Khawar Abbass

    2008-06-01

    Coronary stent fractures are very rare. The predisposing factors for stent fractures are excessive postdilatation, overlapping stents and a hinge site in a tortuous coronary artery. We report a case of very late (after 699 days), displaced, sirolimus-eluting stent fracture deployed at nominal pressures without postdilatation and at a non-hinge portion of the left anterior descending artery. PMID:18523336

  13. Small-Column Cesium Ion Exchange Elution Testing of Spherical Resorcinol-Formaldehyde

    SciTech Connect

    Brown, Garrett N.; Russell, Renee L.; Peterson, Reid A.

    2011-10-21

    This report summarizes the work performed to evaluate multiple, cesium loading, and elution cycles for small columns containing SRF resin using a simple, high-level waste (HLW) simulant. Cesium ion exchange loading and elution curves were generated for a nominal 5 M Na, 2.4E-05 M Cs, 0.115 M Al loading solution traced with 134Cs followed by elution with variable HNO3 (0.02, 0.07, 0.15, 0.23, and 0.28 M) containing variable CsNO3 (5.0E-09, 5.0E-08, and 5.0E-07 M) and traced with 137Cs. The ion exchange system consisted of a pump, tubing, process solutions, and a single, small ({approx}15.7 mL) bed of SRF resin with a water-jacketed column for temperature-control. The columns were loaded with approximately 250 bed volumes (BVs) of feed solution at 45 C and at 1.5 to 12 BV per hour (0.15 to 1.2 cm/min). The columns were then eluted with 29+ BVs of HNO3 processed at 25 C and at 1.4 BV/h. The two independent tracers allowed analysis of the on-column cesium interaction between the loading and elution solutions. The objective of these tests was to improve the correlation between the spent resin cesium content and cesium leached out of the resin in subsequent loading cycles (cesium leakage) to help establish acid strength and purity requirements.

  14. Switching types of drug-eluting stents does not prevent repeated in-stent restenosis in patients with coronary drug-eluting stent restenosis

    PubMed Central

    Yasuoka, Yoshinori; Kume, Kiyoshi; Adachi, Hidenori; Hattori, Susumu; Matsutera, Ryo; Kohama, Yasuaki; Sasaki, Tatsuya

    2014-01-01

    Objectives We treated patients experiencing drug-eluting stent (DES) restenosis with plain old balloon angioplasty (POBA), implantation of the same type of DES [homogeneous drug-eluting stent (HOMO-DES)], or implantation of a different type of DES [heterogeneous drug-eluting stent (HETERO-DES)], and compared the efficacy and safety of these procedures for the prevention of repeated in-stent restenosis (ISR). Background In patients with de-novo coronary lesions, DES implantation is associated with a markedly reduced restenosis rate as compared with that associated with a bare metal stent and POBA. However, the optimal management strategy for patients with DES ISR remains unknown. Patients and methods We identified 191 consecutive DES ISR lesions from 183 patients who required clinically driven revascularization and divided them into three groups according to the treatment: 38 lesions were treated with POBA, 38 with HOMO-DES, and 115 with HETERO-DES. Results The incidence of target lesion revascularization (TLR) was 42.1% (16/38), 15.8% (6/38), and 16.5% (19/115) in the POBA, HOMO-DES, and HETERO-DES groups (POBA vs. HOMO, HETERO-DES; P=0.002, respectively). Multivariate analysis indicated that diabetes [odds ratio (OR), 3.4], hemodialysis (OR, 7.74), nonfocal ISR patterns (OR, 3.35), previous myocardial infarction (OR, 3.26), and POBA (OR, 8.84) were independent predictors of TLR. Conclusion A strategy involving repeated DES implantation was superior to POBA for preventing recurrent restenosis. Treatment with a different type or generation of DES does not appear to reduce the incidence of TLR. Moreover, we identified certain useful factors for facilitating appropriate and early triage in the patients with repeated DES ISR. PMID:25076360

  15. Labview utilities

    Energy Science and Technology Software Center (ESTSC)

    2011-09-30

    The software package provides several utilities written in LabView. These utilities don't form independent programs, but rather can be used as a library or controls in other labview programs. The utilities include several new controls (xcontrols), VIs for input and output routines, as well as other 'helper'-functions not provided in the standard LabView environment.

  16. Comparison of a drug-eluting balloon first and then bare metal stent with a drug-eluting stent for treatment of de novo lesions: study protocol of a randomized controlled trial

    PubMed Central

    2013-01-01

    Background The use of a drug-eluting balloon for the treatment of de novo coronary artery lesions remains to be evaluated. A previous trial in patients with stable and unstable angina comparing a bare metal stent mounted on a drug-eluting balloon with a sirolimus-eluting stent failed to meet the prespecified non-inferiority criteria versus the sirolimus-eluting stent. The stent struts of a bare metal stent pre-mounted on a drug-eluting balloon may prevent the appropriate delivery of drugs to the vessel wall and may result in reduced efficacy. In the present study we will therefore evaluate the efficacy of a drug-eluting balloon for treating de novo coronary artery lesions using a strategy designed to uniformly deliver drug to the vessel with a bare metal stent. Methods/Design The Comparison of Drug-Eluting Balloon first study is a prospective, randomized, open-label trial designed to demonstrate the non-inferiority of first using a drug-eluting balloon (Sequent® please; B. Braun, Melsungen, Germany) followed by a bare metal stent (Coroflex® Blue; B. Braun) compared with using a drug-eluting stent (Resolute Integrity™; Boston Scientific, Natick, MA, USA) for de novo coronary artery lesions. The primary endpoint of the study is in-segment late loss at 9 months measured by quantitative coronary angiography. Secondary endpoints include angiographic findings such as angiographic success, device success, binary angiographic restenosis, and clinical outcomes such as procedural success, all-cause death, myocardial infarction, target vessel revascularization, target lesion revascularization, and stent thrombosis. A total of 180 patients will be enrolled in the study. Discussion The Comparison of Drug-Eluting Balloon first study will evaluate the clinical efficacy, angiographic outcomes and safety of a drug-eluting balloon first followed by a bare metal stent compared with a drug-eluting stent for the treatment of de novo coronary artery lesions. Trial registration

  17. Influence of Sterilization and Storage Period on Elution of Polyvinylpyrrolidone from Wet-Type Polysulfone Membrane Dialyzers.

    PubMed

    Miyata, Masahiro; Konishi, Shuji; Shimamoto, Yoshimasa; Kamada, Aki; Umimoto, Koichi

    2015-01-01

    The objectives of this study were to investigate the influence of the sterilization and storage period on elution of polyvinylpyrrolidone (PVP) from wet-type polysulfone (PSu) membrane dialyzers. APS-15SA (APS) dialyzers sterilized by gamma-radiation and RENAK PS-1.6 (RENAK) dialyzers sterilized by autoclaving were compared in this study. Each dialyzer was washed with physiological saline and the amount of PVP eluted from the PSu membrane was measured. Then, experimental use of each dialyzer was performed by circulating physiological saline for 4 hours, after which the PVP eluted from the PSu membrane was measured. As the results, the amount of PVP eluted by washing was positively correlated with the storage period for both dialyzers (APS: rs = 0.958; RENAK: rs = 0.952). In the experimental circuit, the amount of PVP eluted from the RENAK dialyzer was positively correlated with the storage period (rs = 0.810), whereas the amount of PVP eluted from the APS dialyzer was negatively correlated with the storage period (rs = -0.833). We found that the amount of PVP eluted from PSu membrane is quite different by the sterilization and storage period of dialyzers. PMID:25851313

  18. Method for the analysis of triadimefon and ethofumesate from dislodgeable foliar residues on turfgrass by solid-phase extraction and in-vial elution.

    PubMed

    Runes, H B; Jenkins, J J; Field, J A

    1999-08-01

    Triadimefon, a fungicide, and ethofumesate, an herbicide, are commonly applied to turfgrass in the Pacific Northwest, resulting in foliar residues. A simple and rapid method was developed to determine triadimefon and ethofumesate concentrations from dislodgeable foliar residues on turfgrass. Turfgrass samples were washed, and wash water containing surfactant (a 0.126% solution) was collected for residue analysis. This analytical method utilizes a 25 mm C(8) Empore disk and in-vial elution to quantitatively determine triadimefon and ethofumesate in 170 mL aqueous samples. The analytes were eluted by placing the disk in a 2 mL autosampler vial with 980 microL of ethyl acetate and 20 microL of 2-chlorolepidine, the internal standard, for analysis by GC/MS. The method quantitation limits are 0.29 microg/L for ethofumesate and 0.59 microg/L for triadimefon. The method detection limits are 0.047 microg/L and 0.29 microg/L for ethofumesate and triadimefon, respectively. Concentrations of triadimefon and ethofumesate from dislodgeable foliar residues from a field study are reported. PMID:10552640

  19. Advantages of novel BioMimeTM Sirolimus Eluting Coronary Stent system. Moving towards biomimicry.

    PubMed

    Upendra, K; Sanjeev, B

    2012-02-01

    Since the first reported use of percutaneous transluminal coronary angioplasty (PTCA), advancements in interventional cardiology arena have been fast paced. Within the last ten years, these developments have been exponential. Developers & clinicians are fast adapting from the learning curve awarded by the time course of DES evolution. In that light BioMimeTM Sirolimus Eluting Coronary Stent comes as a fresh thought in taking stents towards a biomimicry concept. The stent is built on an ultra-low strut thickness (65 µm) cobalt chromium stent platform, using an intelligent hybrid of close and open cells allowing for morphology mediated expansion, employs a well known anti-proliferative - Sirolimus that elutes from a biodegradable co-polymer formulation in 30 days and ensures high coating integrity and low coating thickness of 2 µm. The resultant stent demonstrates almost 100% endothelialization at 30 days in preclinical model and zero percent MACE >18 months in the primary efficacy and safety clinical study. PMID:22322571

  20. The Ultimaster Biodegradable-Polymer Sirolimus-Eluting Stent: An Updated Review of Clinical Evidence.

    PubMed

    Chisari, Alberto; Pistritto, Anna Maria; Piccolo, Raffaele; La Manna, Alessio; Danzi, Gian Battista

    2016-01-01

    The Ultimaster coronary stent system (Terumo Corporation, Tokyo, Japan) represents a new iteration in drug-eluting stent (DES) technology that has recently received the Conformité Européenne (CE) mark approval for clinical use. The Ultimaster is a thin-strut, cobalt chromium, biodegradable-polymer, sirolimus-eluting coronary stent. The high elasticity of the biodegradable-polymer (PDLLA-PCL) and the abluminal gradient coating technology are additional novel features of this coronary device. The Ultimaster DES has undergone extensive clinical evaluation in two studies: The CENTURY I and II trials. Results from these two landmark studies suggested an excellent efficacy and safety profile of the Ultimaster DES across several lesion and patient subsets, with similar clinical outcomes to contemporary, new-generation DES. The aim of this review is to summarize the rationale behind this novel DES technology and to provide an update of available evidence about the clinical performance of the Ultimaster DES. PMID:27608017

  1. Everolimus-eluting stent platforms in percutaneous coronary intervention: comparative effectiveness and outcomes.

    PubMed

    Panoulas, Vasileios F; Mastoris, Ioannis; Konstantinou, Klio; Tespili, Maurizio; Ielasi, Alfonso

    2015-01-01

    Despite the remarkable benefits obtained following the introduction of the first-generation drug-eluting stent (DES), concerns were raised over its long-term safety, particularly with regard to very late (beyond 1 year) stent thrombosis. Newer-generation DESs have been developed to overcome this limitation using novel stent platforms, new drugs, more biocompatible durable polymers, and bioabsorbable polymers or backbones. To date, new-generation DESs have virtually replaced the use of first-generation DESs worldwide. In this review article, we discuss in detail the design, pharmacology, and mechanism of action of the newer-generation permanent and bioresorbable everolimus-eluting platforms. Furthermore, we present and evaluate the current evidence on the performance and safety of these devices compared to those of other available stent platforms. PMID:26244031

  2. Acoustophoretic microfluidic chip for sequential elution of surface bound molecules from beads or cells

    PubMed Central

    Augustsson, Per; Malm, Johan; Ekström, Simon

    2012-01-01

    An acoustophoresis-based microfluidic flow-chip is presented as a novel platform to facilitate analysis of proteins and peptides loosely bound to the surface of beads or cells. The chip allows for direct removal of the background surrounding the beads or cells, followed by sequential treatment and collection of a sequence of up to five different buffer conditions. During this treatment, the beads/cells are retained in a single flow by acoustic radiation force. Eluted peptides are collected from the outlets and subsequently purified by miniaturized solid-phase extraction and analyzed with matrix assisted laser desorption mass spectrometry. Fundamental parameters such as the system fluidics and dispersion are presented. The device was successfully applied for wash and sequential elution of peptides bound to the surface of microbeads and human spermatozoa, respectively. PMID:24003343

  3. Everolimus-eluting stent platforms in percutaneous coronary intervention: comparative effectiveness and outcomes

    PubMed Central

    Panoulas, Vasileios F; Mastoris, Ioannis; Konstantinou, Klio; Tespili, Maurizio; Ielasi, Alfonso

    2015-01-01

    Despite the remarkable benefits obtained following the introduction of the first-generation drug-eluting stent (DES), concerns were raised over its long-term safety, particularly with regard to very late (beyond 1 year) stent thrombosis. Newer-generation DESs have been developed to overcome this limitation using novel stent platforms, new drugs, more biocompatible durable polymers, and bioabsorbable polymers or backbones. To date, new-generation DESs have virtually replaced the use of first-generation DESs worldwide. In this review article, we discuss in detail the design, pharmacology, and mechanism of action of the newer-generation permanent and bioresorbable everolimus-eluting platforms. Furthermore, we present and evaluate the current evidence on the performance and safety of these devices compared to those of other available stent platforms. PMID:26244031

  4. Recovery of functional DNA inserts by electroendosmotic elution during gel electrophoresis.

    PubMed Central

    Tan, H V; Kitzis, A; Berthollet, T; Hamard, G; Beldjord, C; Benarous, R

    1988-01-01

    In contrast to all previous preparative electrophoresis apparatus which used a pump, electroendosmotic elution uses bound electrical charges at the end of the separating gel to generate a buffer flow. The electroendosmotic flow increased with increasing currents and decreasing buffer concentrations: its exact characteristics for the built apparatus were determined. The electroendosmotic device was able to separate two DNA fragments differing in size by only 5% with a recovery over 95%. As demonstrated in practical examples of recovery and uses of DNA inserts, up to 10 micrograms of DNA per band can be loaded at a time. The recovered DNA can be used directly for nick-translation, ligation... without further treatment. The performances of the method are expected to improve still further if the charge density and pores of the electroendosmotic medium can be "made-to-order" to provide a better flow profile of the eluting buffer. Images PMID:2833722

  5. Leaching potential of phenylurea herbicides in a calcareous soil: comparison of column elution and batch studies.

    PubMed

    Langeron, Julie; Sayen, Stéphanie; Couderchet, Michel; Guillon, Emmanuel

    2014-04-01

    The transfer of eleven phenylurea herbicides through soil columns was investigated in laboratory conditions in order to determine leaching properties in a calcareous soil. Elution curves with distilled water were plotted after herbicide application on the soil column. Phenylurea retention by the soil indicating interactions with soil can be classified as follows: fenuron < fluometron ≤ isoproturon = monuron < metoxuron < monolinuron < metobromuron < chlorotoluron < linuron = diuron < chlorbromuron. The number and nature of halogen atoms on the phenyl ring had an important influence on leaching. Retention was higher for molecules with higher number of halogen, and it was also higher for bromine than chlorine. Column elution experiments were compared to batch experiments from which the distribution coefficients K d were determined. According to Kendall correlation coefficients, parameter m/m 0 max from column experiments was relatively well linked to K d. In case of phenylurea, a linear relationship between K d and m/m 0 max was established. PMID:23097070

  6. Everolimus-induced Pneumonitis after Drug-eluting Stent Implantation: A Case Report

    SciTech Connect

    Sakamoto, Susumu Kikuchi, Naoshi; Ichikawa, Atsuo; Sano, Go; Satoh, Keita; Sugino, Keishi; Isobe, Kazutoshi; Takai, Yujiro; Shibuya, Kazutoshi; Homma, Sakae

    2013-08-01

    Despite the wide use of everolimus as an antineoplastic coating agent for coronary stents to reduce the rate of restenosis, little is known about the health hazards of everolimus-eluting stents (EES). We describe a case of pneumonitis that developed 2 months after EES implantation for angina. Lung pathology demonstrated an organizing pneumonia pattern that responded to corticosteroid therapy. Although the efficacy of EES for ischemic heart disease is well established, EES carries a risk of pneumonitis.

  7. Stent thrombosis with an aneurysm 7 years after a drug eluting stent implantation

    PubMed Central

    Patil, Pritam; Sethi, Arvind; Kaul, Upendra

    2014-01-01

    We report a case of very late stent thrombosis 7 years post sirolimus eluting stent implantation presenting as ST elevation MI while on dual antiplatelet therapy. Angiography revealed an aneurysm at the proximal end of the stent. The patient was managed successfully by primary percutaneous coronary intervention (PCI) with adjunct thrombus aspiration and intracoronary abciximab administration followed by deploying a mesh-covered stent MGuard. This very late complication is a rare presentation after a drug illuting stent (DES). PMID:24814120

  8. Hepatic Arterial Chemoembolization Using Drug-Eluting Beads in Gastrointestinal Neuroendocrine Tumor Metastatic to the Liver

    SciTech Connect

    Gaur, Shantanu K.; Friese, Jeremy L.; Sadow, Cheryl A.; Ayyagari, Rajasekhara; Binkert, Christoph A.; Schenker, Matthew P.; Kulke, Matthew; Baum, Richard

    2011-06-15

    Purpose: This study was designed to evaluate short (<3 months) and intermediate-term (>3 months) follow-up in patients with metastatic neuroendocrine tumor to the liver who underwent hepatic arterial chemoembolization with drug-eluting beads at a single institution. Methods: Institutional review board approval was obtained for this retrospective review. All patients who were treated with 100-300 or 300-500 {mu}m drug-eluting LC Beads (Biocompatibles, UK) preloaded with doxorubicin (range, 50-100 mg) for GI neuroendocrine tumor metastatic to the liver from June 2004 to June 2009 were included. CT and MRI were evaluated for progression using Response Evaluation Criteria In Solid Tumors (RECIST) or European Association for the Study of the Liver (EASL) criteria. Short-term (<3 months) and intermediate-term (>3 months) imaging response was determined and Kaplan-Meier survival curves were plotted. Results: Thirty-eight drug-eluting bead chemoembolization procedures were performed on 32 hepatic lobes, comprising 21 treatment cycles in 18 patients. All procedures were technically successful with two major complications (biliary injuries). At short-term follow-up (<3 months), 22 of 38 (58%) procedures and 10 of 21 (48%) treatment cycles produced an objective response (OR) with the remainder having stable disease (SD). At intermediate-term follow-up (mean, 445 days; range, 163-1247), 17 of 26 (65%) procedures and 8 of 14 (57%) treatment cycles produced an OR. Probability of progressing was approximately 52% at 1 year with a median time to progression of 419 days. Conclusions: Drug-eluting bead chemoembolization is a reasonable alternative to hepatic arterial embolization and chemoembolization for the treatment of metastatic neuroendocrine tumor to the liver.

  9. Purification of 3-phosphoglycerate kinase from diverse sources by affinity elution chromatography.

    PubMed Central

    Fifis, T; Scopes, R K

    1978-01-01

    1. Affinity elution chromatography was used to purify phosphoglycerate kinase from a variety of sources. The choice of buffer pH for the chromatography was made according to the relative electrophoretic mobility of the enzyme from the species concerned. 2. Outlines of the methods used to isolate the enzyme from over 20 sources are presented. The enzyme was purified from the muscle tissue of a variety of mammals, fish and birds, from liver of several animals, from yeast, Escherichia coli, and plant leaves. The more acidic varieties of the enzymes were purified by conventional gradient elution from ion-exchangers as affinity elution procedures were not applicable. 3. The structural and kinetic parameters investigated show that phosphoglycerate kinase is evolutionarily a highly conservative enzyme; there were few differences in properties regardless of source or function (glycolytic, gluconeogenic or photosynthetic). 4. A detailed comparison of the enzyme preparations purified from bovine muscle and bovine liver failed to detect any significant differences between them; the evidence indicates that they are genetically identical. PMID:367367

  10. In vitro hemocompatibility and cytocompatibility of dexamethasone-eluting PLGA stent coatings

    NASA Astrophysics Data System (ADS)

    Zhang, Jiang; Liu, Yang; Luo, Rifang; Chen, Si; Li, Xin; Yuan, Shuheng; Wang, Jin; Huang, Nan

    2015-02-01

    Drug-eluting stents (DESs) have been an important breakthrough for interventional cardiology applications since 2002. Though successful in reducing restenosis, some adverse clinical problems still emerged, which were mostly caused by the bare-metal stents and non-biodegradable polymer coatings, associated with the delayed endothelialization process. In this study, dexamethasone-loaded poly (lactic-co-glycolic acid) (PLGA) coatings were developed to explore the potential application of dexamethasone-eluting stents. Dexamethasone-eluting PLGA stents were prepared using ultrasonic atomization spray method. For other tests like stability and cytocompatibility and hemocompatibility tests, dexamethasone loaded coatings were deposited on 316L SS wafers. Fourier transform-infrared spectroscopy (FT-IR) results demonstrated that there was no chemical reaction between PLGA and dexamethasone. The balloon expansion experiment and surface morphology observation suggested that the stent coatings were smooth and uniform, and could also withstand the compressive and tensile strains imparted without cracking after stent expansion. The drug release behavior in vitro indicated that dexamethasone existed burst release within 1 day, but it presented linear release characteristics after 6 days. In vitro platelets adhesion, activation test and APTT test were also done, which showed that after blending dexamethasone into PLGA, the hemocompatibility was improved. Besides, dexamethasone and dexamethasone-loaded PLGA coatings could significantly inhibit the attachment and proliferation of smooth muscle cells.

  11. Elution kinetics, antimicrobial activity, and mechanical properties of 11 different antibiotic loaded acrylic bone cement.

    PubMed

    Gálvez-López, Ruben; Peña-Monje, Alejandro; Antelo-Lorenzo, Ramón; Guardia-Olmedo, Juan; Moliz, Juan; Hernández-Quero, José; Parra-Ruiz, Jorge

    2014-01-01

    Antibiotic-loaded acrylic bone cements (ALABC) spacers are routinely used in the treatment of prosthetic joint infections. The objectives of our study were to evaluate different ALABC for elution kinetics, thermal stability, and mechanical properties. A 10 or 20% mixture (w/w) beads of medium viscosity bone cement (DePuy, Inc) and vancomycin (VAN), gentamycin (GM), daptomycin (DAP), moxifloxacin (MOX), rifampicin (RIF), cefotaxime (CTX), cefepime (FEP), amoxicillin clavulanate (AmC), ampicillin (AMP), meropenem (MER), and ertapenem (ERT) were formed and placed into wells filled with phosphate-buffered saline. Antibiotic concentrations were determined using high-performance liquid chromatography. Antimicrobial activity was tested against Micrococcus luteus ATCC 9341 or Escherichia coli ATCC 25922. AmC, AMP, and FEP concentration rapidly decreased after day 2, being almost undetectable at day 4. Sustained and high elution rates were observed with VAN, GM, MOX, and RIF for the 30-day duration of the experiment. DAP, MER, ERT, and CTX elution rates constantly decreased from day 4. All antibiotics tested retained antimicrobial activity proving thermal stability. Mechanical properties of ALABC were maintained except when RIF was used. PMID:24231380

  12. Drug-eluting microarrays to identify effective chemotherapeutic combinations targeting patient-derived cancer stem cells

    PubMed Central

    Carstens, Matthew R.; Fisher, Robert C.; Acharya, Abhinav P.; Butterworth, Elizabeth A.; Scott, Edward; Huang, Emina H.; Keselowsky, Benjamin G.

    2015-01-01

    A new paradigm in oncology establishes a spectrum of tumorigenic potential across the heterogeneous phenotypes within a tumor. The cancer stem cell hypothesis postulates that a minute fraction of cells within a tumor, termed cancer stem cells (CSCs), have a tumor-initiating capacity that propels tumor growth. An application of this discovery is to target this critical cell population using chemotherapy; however, the process of isolating these cells is arduous, and the rarity of CSCs makes it difficult to test potential drug candidates in a robust fashion, particularly for individual patients. To address the challenge of screening drug libraries on patient-derived populations of rare cells, such as CSCs, we have developed a drug-eluting microarray, a miniaturized platform onto which a minimal quantity of cells can adhere and be exposed to unique treatment conditions. Hundreds of drug-loaded polymer islands acting as drug depots colocalized with adherent cells are surrounded by a nonfouling background, creating isolated culture environments on a solid substrate. Significant results can be obtained by testing <6% of the cells required for a typical 96-well plate. Reliability was demonstrated by an average coefficient of variation of 14% between all of the microarrays and 13% between identical conditions within a single microarray. Using the drug-eluting array, colorectal CSCs isolated from two patients exhibited unique responses to drug combinations when cultured on the drug-eluting microarray, highlighting the potential as a prognostic tool to identify personalized chemotherapeutic regimens targeting CSCs. PMID:26124098

  13. The role of CABG in the era of drug-eluting stents: a surgeon's viewpoint

    PubMed Central

    Teoh, L K Kristine; Lee, Chuen Neng

    2010-01-01

    Advances in transcatheter technologies, from balloon angioplasty to bare metal stents to drug-eluting stents, have resulted in improved outcomes following percutaneous coronary intervention (PCI). As a consequence, the differences in outcomes between coronary artery bypass graft surgery (CABG) and PCI have become less significant over short-term follow-up. In addition, the number of patients undergoing coronary revascularisation with PCI has increased and far exceeds that of CABG, which has declined, the ratio stabilising in recent years. With the advent of drug-eluting stents and the increasing off-label use of these stents—and in the setting of questionable public awareness of the relative risks and benefits of the therapeutic options of optimal medical treatment and revascularisation by PCI or CABG—the role of CABG requires clarification and reaffirmation. Recent clinical trials have helped to better define the relative benefits of each treatment modality. The mid- and long-term results of these studies remain to be seen, however, while the evidence for the role of PCI in left main stem disease remains inconclusive at the present time. In this context of continually emerging clinical evidence, this review seeks to provide a balanced opinion regarding the role of CABG in the era of drug-eluting stents.

  14. Drug-eluting balloon: Initial experience in patients with in-stent restenosis (ISR)

    PubMed Central

    Swamy, A.J.; Kumar, Anil; Keshavamurthy, G.; Chadha, D.S.

    2014-01-01

    Background In-stent restenosis is the most important limitation of modern coronary angioplasty. Drug-eluting stents solve this problem but at the cost of late stent thrombosis and longer duration of dual-antiplatelet therapy. Drug-eluting balloon (DEB) technology is now available and offers an attractive option for treatment of restenosis. Methods A cohort of 20 patients with in-stent restenosis after stenting were treated with a drug-eluting balloon and were followed up clinically and angiographically for 6 months. Results and conclusion Procedural success was achieved in all patients. 6 month clinical follow-up was available for all and 6 month angiographic follow up for 17 patients. On 6 month follow-up, 5 of the 20 patients had recurrence of angina and 4 patients had angiographic restenosis (2 focal, 2 diffuse). The mean Canadian Cardiovascular Society angina score improved significantly from 3.1 to 1.1. DEB offers a novel method of treatment for patients with in-stent restenosis with a good safety and efficacy profile. PMID:25378777

  15. Very Late Stent Thrombosis 11 Years after Implantation of a Drug-Eluting Stent

    PubMed Central

    Jepson, Nigel

    2015-01-01

    Very late stent thrombosis is an infrequent yet potentially fatal complication associated with drug-eluting stents. We report the case of an 88-year-old man who sustained an ST-segment-elevation myocardial infarction 11 years after initial sirolimus-eluting stent implantation. Optical coherence tomograms of the lesion showed that the focal incomplete endothelialization of the stent struts was the likely cause; neointimal formation, neoatherosclerosis, and late stent malapposition might also have contributed. To our knowledge, this is the longest reported intervening period between stent insertion and the development of an acute coronary event secondary to very late stent thrombosis. The associated prognostic and therapeutic implications are considerable, because they illuminate the uncertainties surrounding the optimal duration of antiplatelet therapy in patients who have drug-eluting stents. Clinicians face challenges in treating these patients, particularly when competing medical demands necessitate the discontinuation of antiplatelet therapy. In addition to the patient's case, we discuss factors that can contribute to very late stent thrombosis. PMID:26504449

  16. Blood compatibility assessment of polymers used in drug eluting stent coatings.

    PubMed

    Szott, Luisa Mayorga; Irvin, Colleen A; Trollsas, Mikael; Hossainy, Syed; Ratner, Buddy D

    2016-06-01

    Differences in thrombosis rates have been observed clinically between different drug eluting stents. Such differences have been attributed to numerous factors, including stent design, injury created by the catheter delivery system, coating application technologies, and the degree of thrombogenicity of the polymer. The relative contributions of these factors are generally unknown. This work focuses on understanding the thrombogenicity of the polymer by examining mechanistic interactions with proteins, human platelets, and human monocytes of a number of polymers used in drug eluting stent coatings, in vitro. The importance for blood interactions of adsorbed albumin and the retention of albumin was suggested by the data. Microscopic imaging and immunostaining enhanced the interpretation of results from the lactate dehydrogenase cell counting assay and provided insight into platelet interactions, total quantification, and morphometry. In particular, highly spread platelets may be surface-passivating, possibly inhibiting ongoing thrombotic events. In many of the assays used here, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) showed a differentiated protein deposition pattern that may contribute to the explanation of the consistently thromboresistant blood-materials interaction for fluororpolymers cited in literature. These results are supportive of one of several possible factors contributing to the good thromboresistant clinical safety performance of PVDF-HFP coated drug eluting stents. PMID:27083991

  17. The pre-clinical assessment of rapamycin-eluting, durable polymer-free stent coating concepts.

    PubMed

    Steigerwald, Kristin; Merl, Sabine; Kastrati, Adnan; Wieczorek, Anna; Vorpahl, Marc; Mannhold, Raimund; Vogeser, Michael; Hausleiter, Jörg; Joner, Michael; Schömig, Albert; Wessely, Rainer

    2009-02-01

    All four currently FDA-approved drug-eluting stents (DESs) contain a durable polymeric coating which can negatively impact vascular healing processes and eventually lead to adverse cardiac events. Aim of this study was the pre-clinical assessment of two novel rapamycin-eluting stent (RES) coating technologies that abstain from use of a durable polymer. Two distinctive RES coating technologies were evaluated in vitro and in the porcine coronary artery stent model. The R-poly(S) stent platform elutes rapamycin from a biodegradable polymer that is top coated with the resin shellac to minimize the amount of polymer. The R-pro(S) stent platform allows dual drug release of rapamycin and probucol, blended by shellac. HPLC-based determination of pharmacokinetics indicated drug release for more than 28 days. At 30 days, neointimal formation was found to be significantly decreased for both DESs compared to bare-metal stents. Assessment of vascular healing revealed absence of increased inflammation in both DESs, which is commonly observed in DES with non-erodible polymeric coating. In conclusion, the pre-clinical assessment of RESs with resin-based or dual drug coating indicated an adequate efficacy profile as well as a beneficial effect for vascular healing processes. These results encourage the transfer of these technologies to clinical evaluation. PMID:18990438

  18. Megasonic sonication for cost-effective and automatable elution of Cryptosporidium from filters and membranes.

    PubMed

    Kerrouche, Abdelfateh; Desmulliez, Marc P Y; Bridle, Helen

    2015-11-01

    Sample processing is a highly challenging stage in the monitoring of waterborne pathogens. This step is time-consuming, requires highly trained technicians and often results in low recovery rates of pathogens. In the UK but also in other parts of the world, Cryptosporidium is the only pathogen directly tested for in routine operational monitoring. The traditional sampling process involves the filtration of 1000L of water, semi-automated elution of the filters and membranes with recovery rates of about 30-40% typically. This paper explores the use of megasonic sonication in an attempt to increase recovery rates and reduce both the time required for processing and the number of labour-intensive steps. Results demonstrate that megasonic energy assisted elution is equally effective as the traditional manual process in terms of recovery rates. Major advantages are however offered in terms of reduction of the elution volume enabling the current centrifugation stage to be avoided. This saves time, equipment and staff costs and critically removes the step in the process that would be most challenging to automate, paving the way thereby for highly effective automated solutions to pathogens monitoring. PMID:26363087

  19. In Vitro Elution Characteristics of Gentamicin and Vancomycin from Synthetic Bone Graft Substitutes

    PubMed Central

    Maier, Gerrit Steffen; Roth, Klaus Edgar; Andereya, Stefan; Birnbaum, Klaus; Niedhart, Christopher; Lühmann, Markus; Ohnsorge, Jörg; Maus, Uwe

    2013-01-01

    Objects: Beta tricalciumphosphate pellets loaded with individualized antibiotics may represent novel options in the treatment of osteomyelitis and infectious bone disease. Here, the in vitro antibiotic elution of vancomycin and gentamicin from the synthetic bone graft substitutes Cerasorb® and Cerasorb M® was tested. Methods: Antibiotic elution and concentration of gentamcin and vancomycin were measured using photometrically-based measurement and homogeneous particle-enhanced turbidimetric inhibition immunoassays (PETINIA). Results: Initially both materials showed a high release of the loaded antibiotics, with Cerasorb M® showing lower release levels for gentamicin and vancomycin than Cerasorb®. Gentamicin concentrations of Cerasorb M granules and Cerasorb were below the minimum detectiontreshold until day four and six of the experiment respectively. The vancomycin release-level followed a similar pattern, although the vancomycin concentration eluted by Cerasorb M® granules stayed above the detection threshold during the experimental time. Conclusions: Cerasorb® and Cersorb M® may represent a new treatment option in osteomyelitis and infectious bone disease. PMID:24285988

  20. Protein adsorption to poly(ethylenimine)-modified Sepharose FF. IV. Dynamic adsorption and elution behaviors.

    PubMed

    Liu, Na; Yu, Lin-Ling; Sun, Yan

    2014-10-01

    We have previously investigated bovine serum albumin (BSA) uptake to poly(ethylenimine) (PEI)-grafted Sepharose FF. It was found that there was a critical ionic capacity (cIC; 600mmol/L) for BSA, above which the protein adsorption capacity and uptake kinetics increased drastically. In this work, two poly(ethylenimine) (PEI)-grafted resins with IC values of 271mmol/L (FF-PEI-L270) and 683mmol/L (FF-PEI-L680), which were below and above the cIC, respectively, were chosen to investigate the breakthrough and linear gradient elution (LGE) behaviors of BSA. Commercially available anion exchanger, Q Sepharose FF, was used for comparison. The DBC values of FF-PEI-L680 were much higher in the entire residence time range (2-10min) than the other two resins due to its high static adsorption capacity and uptake kinetics. At a residence time of 5.0min, the DBC of FF-PEI-L680 (104mg/mL) was about seven times that of FF-PEI-L270 and three times that of Q Sepharose FF. A rise-fall trend of the DBCs with increasing ionic strength (IS) was found for all the three resins studied, indicating the presence of electrostatic exclusion for protein uptake at low IS. With increasing NaCl concentration from 20 to 200mmol/L, FF-PEI-L680 kept very high DBC values (64-114mg/mL). In addition, FF-PEI-L270 showed more favorable adsorption properties than Q Sepharose FF at 100-300mmol/L NaCl. These results proved that the three-dimensional grafting ion exchange layer on the PEI resins enhanced their tolerance to IS. In the study of LGE, the three resins showed similar elution behaviors and no distinct peak tailings were observed. The salt concentrations at the elution peaks (IR) were in the order of FF-PEI-L680>FF-PEI-L270>Q Sepharose FF, indicating that the elution for the PEI resins needed higher salt concentrations, which was also an appearance of the salt-tolerant feature of the PEI resins. When protein loading amount was increased to the value equivalent to the DBC at 10% breakthrough, the

  1. Comparison on the efficacy of everolimus-eluting stent and zotarolimus-eluting stents in coronary heart disease between diabetic and non-diabetic patients

    PubMed Central

    Lin, Liming; Jin, Cheng; Wei, Xiaoming; Li, Huiying; Shi, Jihong; Wu, Shouling; Yang, Xiaojie; Qi, Xiangqian

    2015-01-01

    Objective: The aim of this study is to examine and compare the efficacy of everolimus-eluting stents (EES) and zotarolimus-eluting stents (ZES) in coronary heart disease in diabetic or non-diabetic patients. Methods: A total of 666 patients needed for percutaneous coronary intervention were randomly selected from June 2008 to June 2013 in our hospital and were divided into two groups: (i) coronary heart disease with diabetes group and (ii) non-diabetes group. Patients in each group were further assigned to receive treatment of either EES or ZES. Then we observed the major adverse cardiac events, including mortality, nonfatal myocardial infarction and non-fatal cerebrovascular events over the period of 15 months after initial stent implantation. Results: Compared to the non-diabetic group, more patients in diabetic group had received anti-hypotensive treatment (72% vs. 49%, P < 0.0001) and hypolipemic treatment (80% vs. 67%, P < 0.0001) before the percutaneous coronary intervention. In both diabetic group and non-diabetic group, patients received ZES treatment had a much greater incidence rate of major adverse cardiac events compared to the patients received EES treatment (P < 0.05). Meanwhile, target lesion revascularization rate in the ZES group was also significantly higher than that in the EES group. The data showed big differences between ZES and EES groups with important statistical significance (P < 0.05). Conclusion: Patients with coronary heart disease and diabetes have a higher risk of major adverse cardiac events after stent implantation. EES treatment is safer with higher efficacy in our study, being a more effective stent for the patients merged with diabetes. PMID:26885005

  2. Longer storage of dialyzers increases elution of poly(N-vinyl-2-pyrrolidone) from polysulfone-group dialysis membranes.

    PubMed

    Namekawa, Koki; Kaneko, Ami; Sakai, Kiyotaka; Kunikata, Satoru; Matsuda, Masato

    2011-03-01

    The objective of this study was to evaluate the effect of protracted storage of dialyzers on the amount of poly(N-vinyl-2-pyrrolidone) (PVP) eluted from polysulfone-group dialysis membranes. We tested five dialysis membranes: APS-15SA (Asahi Kasei Kuraray, wet), CX-1.6U (Toray, moist), FX140 (Fresenius, dry), PES-15Sα (Nipro, dry), and FDX-150GW (Nikkiso, wet). Each dialyzer was stored for 1, 3, 14, and 18 months after sterilization. The dialysis-fluid side compartment was primed with reverse osmosis (RO) water at 500 mL/min for 5 min at 310 K. The blood side compartment was primed with RO water at 200 mL/min for 5 min at 310 K. Finally, 1 L RO water was circulated through the blood side compartment at 200 mL/min for 4 h at 310 K. Eluted PVP was determined by use of the iodine method, using 0.02 N: iodine solution. PVP was mainly eluted from wet-type dialyzers during priming. Thus, the standard 5 min priming of the wet-type dialyzer according to the maker manual inhibits PVP elution during circulation. PVP was eluted in the dialysis-fluid side of the moist-type dialyzer during priming but no PVP was eluted in the blood side. PVP was mainly eluted from dry-type dialyzers during circulation. We recommend more than the standard 5 min priming, particularly for dry-type dialyzers stored for protracted periods, because 5 min insufficient to inhibit PVP elution during circulation. PMID:21286768

  3. Poly(N-vinyl-2-pyrrolidone) elution from polysulfone dialysis membranes by varying solvent and wall shear stress.

    PubMed

    Namekawa, Koki; Matsuda, Masato; Fukuda, Makoto; Kaneko, Ami; Sakai, Kiyotaka

    2012-06-01

    Some dialysis patients are treated with post-hemodiafiltration (HDF); the blood viscosity of the patients who undergo post-HDF is higher than that of the patients who undergo conventional hemodialysis. This study aims to evaluate poly(N-vinyl-2-pyrrolidone) (PVP) elution from PSf dialysis membranes by varying solvents and high wall shear stress caused by blood viscosity. We tested three commercial membranes: APS-15SA (Asahi Kasei Kuraray), CX-1.6U (Toray) and FX140 (Fresenius). Dialysate and blood sides of the dialyzers were primed with reverse osmosis (RO) water and saline. RO water, saline and dextran solution (2.9 and 5.8 mPa s) were circulated in the blood side. The amount of eluted PVP was determined by 0.02 N iodometry. The hardness and adsorption force of human serum albumin (HSA) on the membrane surfaces were measured by the atomic force microscope. When wall shear stress was increased using dextran, the amount of PVP eluted by the 2.9 mPa s solution equaled that eluted by the 5.8 mPa s solution with APS-15SA and CX-1.6U sterilized by gamma rays. The amount of PVP eluted by the 5.8 mPa s solution was higher than that eluted by the 2.9 mPa s solution with FX140 sterilized by autoclaving. The wall shear stress increased the PVP elution from the surface, hardness and adsorption force of HSA. Sufficient gamma-ray irradiation is effective in decreasing PVP elution. PMID:22311608

  4. Influence of amount of oxidizing slag discharged from stainless steelmaking process of electric arc furnace on elution behavior into fresh water

    NASA Astrophysics Data System (ADS)

    Yokoyama, S.; Shimomura, T.; Hisyamudin, M. N. N.; Takahashi, T.; Izaki, M.

    2012-03-01

    Fundamental study was carried out for provision for acidification of soil due to acid rain. The influence of weight of the additive slag on elution behavior of the slag into water was studied in this study. Elution experiment was carried out on a basis of JIS K 0058-1. Generally, the pH in the aqueous solution increased with an increase in weight of the additive slag. The pH converged to approximately eight. Calcium, magnesium and manganese, which were essential elements for plants, were eluted from the slag irrespective to elution condition. The eluted concentrations of Ca and Mg increased with an increase in weight of the additive slag. Silicon and zinc were also eluted depending on the conditions. Aluminum that was harmful for plants was not eluted from the used slag.

  5. Comparison of zonal elution and nonlinear chromatography in determination of the interaction between seven drugs and immobilised β(2)-adrenoceptor.

    PubMed

    Li, Qian; Wang, Jing; Zheng, Yuqing Yuan; Yang, Lingjian; Zhang, Yajun; Bian, Liujiao; Zheng, Jianbin; Li, Zijian; Zhao, Xinfeng; Zhang, Youyi

    2015-07-01

    Zonal elution and nonlinear chromatography are two mainstream models for the determination of drug-protein interaction in affinity chromatography. This work intended to compare the results by zonal elution with that by nonlinear chromatography when it comes to the analysis of the interaction between seven drugs and immobilised β2-adrenoceptor (β2-AR). The results of the zonal elution showed that clorprenaline, clenbuterol, methoxyphenamine, salbutamol, terbutaline, tulobuterol and bambuterol have only one type of binding site on immobilised β2-AR, while nonlinear chromatography confirmed the existence of at least two types of binding sites between β2-AR and clorprenaline, clenbuterol and bambuterol. On these sites, both zonal elution and nonlinear chromatography presented the same rank order for the association constants of the seven drugs. Compared with the data from zonal elution, the association constants calculated using nonlinear chromatography gave a good linear response to the corresponding values by radio-ligand binding assay. The sampling efficiencies of nonlinear chromatography were clearly higher than zonal elution. Nonlinear chromatography will probably become a powerful alternative for the high throughput determination of drug-protein interaction. PMID:26002106

  6. Retention prediction and separation optimization under multilinear gradient elution in liquid chromatography with Microsoft Excel macros.

    PubMed

    Fasoula, S; Zisi, Ch; Gika, H; Pappa-Louisi, A; Nikitas, P

    2015-05-22

    A package of Excel VBA macros have been developed for modeling multilinear gradient retention data obtained in single or double gradient elution mode by changing organic modifier(s) content and/or eluent pH. For this purpose, ten chromatographic models were used and four methods were adopted for their application. The methods were based on (a) the analytical expression of the retention time, provided that this expression is available, (b) the retention times estimated using the Nikitas-Pappa approach, (c) the stepwise approximation, and (d) a simple numerical approximation involving the trapezoid rule for integration of the fundamental equation for gradient elution. For all these methods, Excel VBA macros have been written and implemented using two different platforms; the fitting and the optimization platform. The fitting platform calculates not only the adjustable parameters of the chromatographic models, but also the significance of these parameters and furthermore predicts the analyte elution times. The optimization platform determines the gradient conditions that lead to the optimum separation of a mixture of analytes by using the Solver evolutionary mode, provided that proper constraints are set in order to obtain the optimum gradient profile in the minimum gradient time. The performance of the two platforms was tested using experimental and artificial data. It was found that using the proposed spreadsheets, fitting, prediction, and optimization can be performed easily and effectively under all conditions. Overall, the best performance is exhibited by the analytical and Nikitas-Pappa's methods, although the former cannot be used under all circumstances. PMID:25869801

  7. Antibiotic eluting clay mineral (Laponite®) for wound healing application: an in vitro study.

    PubMed

    Ghadiri, M; Chrzanowski, W; Rohanizadeh, R

    2014-11-01

    Different materials in form of sponge, hydrogel and film have been developed and formulated for treating and dressing burn wounds. In this study, the potential of Laponite, a gel forming clay, in combination with an antimicrobial agent (mafenide), as a wound dressing material was tested in vitro. Laponite/mafenide (Lap/Maf) hydrogel was formulated in three different ratios of Lap/Maf 1:1, 1:2, 1:3. Laponite/mafenide/alginate (Lap/Maf/Alg) film was also formulated by combining Lap/Maf gel (1:1) with alginate. Intercalation rate of mafenide into the layers of Laponite nanoparticles and physico-chemical properties, including wound dressing characteristics of materials were studied using various analytical methods. Furthermore, the degradation of materials and the release profile of mafenide were investigated in simulated wound exudates fluid and antibacterial effectiveness of the eluted mafenide was tested on a range of bacterial species. The cytotoxicity of materials was also evaluated in skin fibroblast culture. The results showed that mafenide molecules were intercalated between the nano-sized layers of Laponite. The eluted mafenide showed active antibacterial effects against all three tested bacteria. All intercalated mafenide released from Lap/Maf 1:1 and 1:2 gel formulations and nearly 80% release from 1:3 formulation during test period. No significant difference was observed in release profile of mafenide between Lap/Maf/Alg film and Lap/Maf formulations. Wound dressing tests on Lap/Maf/Alg film showed it is a breathable dressing and has capacity to absorb wound exudates. The study showed that prepared Lap/Maf composite has the potential to be used as an antibiotic eluting gel or film for wound healing application. Additionally, Laponite has shown benefits in wound healing processes by releasing Mg(2+) ions and thereby reducing the cytotoxic effect of mafenide on fibroblast cells. PMID:25027303

  8. Simple automated generation of gradient elution conditions in sequential injection chromatography using monolithic column.

    PubMed

    Koblová, Petra; Sklenářová, Hana; Chocholouš, Petr; Polášek, Miroslav; Solich, Petr

    2011-06-15

    The paper deals with the concept of simple automated creation of gradient profile of the mobile phase for gradient-elution sequential injection chromatography (GE-SIC). The feasibility and merits of this concept are demonstrated on the separation and simultaneous assay of indomethacin as active principle and of its two degradation products (5-methoxy-2-methylindoleacetic acid and 4-chloro-benzoic acid) in a topical pharmaceutical formulation. The GE-SIC separation was performed with a FIAlab(®) 3000 SIC set-up (USA) equipped with an Onyx™ Monolithic C18 (25 mm × 4.6mm, Phenomenex(®)) column, a six-port selection valve, a 5-mL syringe pump and a fiber-optics UV CCD detector. Ketoprofen was used as an internal standard (IS). The gradient elution was achieved by automated reproducible mixing of acetonitrile and aqueous 0.2% phosphoric acid in the holding coil of the SIC system. Different profiles of the gradient elution were tested. The optimal gradient using two mobile phases 30:70 and 50:50 of acetonitrile/0.2% phosphoric acid (v/v) was achieved under the optimum flow rate 1.2 mL min(-1). The chromatographic resolution R between the peaks of all solutes (including the IS) was >2.00. The repeatability of retention times was characterized by the RSD values 0.18-0.30% (n=6). Net separation time was 3.5 min and the mobile phase consumption was 4.5 mL for a single GE-SIC assay. The figures of merit of the novel GE-SIC method compared well with those of conventional HPLC. PMID:21641437

  9. Cochlear implant and inflammation reaction: Safety study of a new steroid-eluting electrode.

    PubMed

    Astolfi, L; Simoni, E; Giarbini, N; Giordano, P; Pannella, M; Hatzopoulos, S; Martini, A

    2016-06-01

    Dexamethasone is a common anti-inflammatory agent added to cochlear implants to reduce hearing loss due to electrode insertion trauma. We evaluated the safety of eluting silicone rods containing 10% dexamethasone in a Guinea pig model. Animals were implanted with a dexamethasone eluting silicone electrode (DER) or with a non-eluting electrode (NER). The control group only underwent a cochleostomy (CS). Prior to implantation and during the two weeks following implantation, the hearing status of the animals was assessed by means of Compound Action Potentials (CAPs) with an electrode placed near the round window. Two weeks after implantation, the mean click threshold shifts were 1 dB ± 10 dB in the DER group, 10 dB ± 10 dB in the NER group and -4 dB ± 10 dB in the control group. After two weeks the bullae of each animal were extracted to verify the presence of macrophages, the percent of tissue growth in the scala tympani and the tissue sealing around cochleostomy. Silicone electrodes samples were also explanted and examined for bacterial infection. Neither bacterial infection nor enhanced number of macrophages were observed. A limited, but not significant, tissue growth was found in the scala tympani between the experimental and the control group. The data suggest that, in the Guinea pig model, the use of DER is apparently safe as an anti-inflammatory slow-release additive to the cochlear implant. PMID:27109196

  10. Impact of Statin Treatment on Strut Coverage after Drug-Eluting Stent Implantation

    PubMed Central

    Suh, Yongsung; Kim, Byeong-Keuk; Shin, Dong-Ho; Kim, Jung-Sun; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo

    2015-01-01

    Purpose To evaluate the effect of statin treatment on strut coverage after drug-eluting stent (DES) implantation. Materials and Methods In this study, 60 patients were randomly assigned to undergo sirolimus-eluting stent (SES) or biolimus-eluting stent (BES) implantation, after which patients were randomly treated with pitavastatin 2 mg or pravastatin 20 mg for 6 months. The degree of strut coverage was assessed by 6-month follow-up optical coherence tomography, which was performed in 52 DES-implanted patients. Results The percentages of uncovered struts were 19.4±14.7% in pitavastatin-treated patients (n=25) and 19.1±15.2% in pravastatin-treated patients (n=27; p=0.927). A lower percentage of uncovered struts was significantly correlated with a lower follow-up low-density lipoprotein (LDL) cholesterol level (r=0.486; p=0.009) and a greater decline of the LDL cholesterol level (r=-0.456; p=0.015) in SES-implanted patients, but not in BES-implanted patients. In SES-implanted patients, the percentage of uncovered struts was significantly lower among those with LDL cholesterol levels of less than 70 mg/dL after 6 months of follow-up (p=0.025), but no significant difference in this variable according to the follow-up LDL cholesterol level was noted among BES-implanted patients (p=0.971). Conclusion Lower follow-up LDL cholesterol levels, especially those less than 70 mg/dL, might have a protective effect against delayed strut coverage after DES implantation. This vascular healing effect of lower LDL cholesterol levels could differ according to the DES type. PMID:25510746

  11. Miniaturized Self-Expanding Drug-Eluting Stent in Small Coronary Arteries: Late Effectiveness

    PubMed Central

    de Oliveira, Flavio Roberto Azevedo; Mattos, Luiz Alberto Piva e; Abizaid, Alexandre; Abizaid, Andrea S.; Costa, J. Ribamar; Costa, Ricardo; Staico, Rodolfo; Botelho, Roberto; Sousa, J. Eduardo; Sousa, Amanda

    2013-01-01

    Background Small vessels represent a risk factor for restenosis in percutaneous coronary angioplasty (PCA). The Sparrow® self-expanding drug-eluting stent, which has a lower profile than the current systems, has never been tested in this scenario. Objectives To evaluate the late effectiveness of the Sparrow® drug-eluting stent, regarding in-stent late lumen loss (LLL). Methods Patients with ischemia, symptomatic or documented, were submitted to PCA in vessels with reference diameter < 2.75 mm, divided into two groups regarding Sparrow® stent type: group 1: Sparrow® drug-eluting stent (DES), group 2: Sparrow® bare metal stent (BMS). Clinical follow-up duration was 12 months. Evaluation using quantitative coronary angiography (QCA) was performed immediately and at 8 months. A decrease of over 65% of in-stent LLL with DES was estimated to calculate sample size. IBM® SPSS software, release 19 (Chicago, Illinois, USA) was used for the statistical analysis. Results A total of 24 patients were randomized, 12 in each group. The DES and BMS groups were similar in age (63.25 ± 10.01 vs. 64.58 ± 11.54, p = 0.765), male gender (58.3% vs. 33.3%, p = 0.412), risk factors and all angiographs aspects. Immediate results were satisfactory in both groups. At 8 months in-stent late lumen loss was significantly lower in DES than in BMS group (DES vs. BMS 0.25 ± 0.16 0.97 ± 0.76, p = 0.008). Conclusion In small-vessel PCA, the Sparrow® DES determined significant reduction in in-stent LLL, when compared to Sparrow® BMS. PMID:24100691

  12. Spectral Analysis Related to Bare-Metal and Drug-Eluting Coronary Stent Implantation

    PubMed Central

    da Silva, Rose Mary Ferreira Lisboa; Silva, Carlos Augusto Bueno; Greco, Otaviano José; Moreira, Maria da Consolação Vieira

    2014-01-01

    Background The autonomic nervous system plays a central role in cardiovascular regulation; sympathetic activation occurs during myocardial ischemia. Objective To assess the spectral analysis of heart rate variability during stent implantation, comparing the types of stent. Methods This study assessed 61 patients (mean age, 64.0 years; 35 men) with ischemic heart disease and indication for stenting. Stent implantation was performed under Holter monitoring to record the spectral analysis of heart rate variability (Fourier transform), measuring the low-frequency (LF) and high-frequency (HF) components, and the LF/HF ratio before and during the procedure. Results Bare-metal stent was implanted in 34 patients, while the others received drug-eluting stents. The right coronary artery was approached in 21 patients, the left anterior descending, in 28, and the circumflex, in 9. As compared with the pre-stenting period, all patients showed an increase in LF and HF during stent implantation (658 versus 185 ms2, p = 0.00; 322 versus 121, p = 0.00, respectively), with no change in LF/HF. During stent implantation, LF was 864 ms2 in patients with bare-metal stents, and 398 ms2 in those with drug-eluting stents (p = 0.00). The spectral analysis of heart rate variability showed no association with diabetes mellitus, family history, clinical presentation, beta-blockers, age, and vessel or its segment. Conclusions Stent implantation resulted in concomitant sympathetic and vagal activations. Diabetes mellitus, use of beta-blockers, and the vessel approached showed no influence on the spectral analysis of heart rate variability. Sympathetic activation was lower during the implantation of drug-eluting stents. PMID:25029473

  13. Quantitation of specific proteins in polyacrylamide gels by the elution of Fast Green FCF.

    PubMed

    Gilmore, L B; Hook, G E

    1981-07-01

    The quantitation of proteins in polyacrylamide gels stained with Fast green FCF has been investigated using a modification of the elution technique originally described by Fenner et al. (Fenner, C., Traut, R.R., Mason, D.T. and Wikman-Coffelt, J. (1975) Anal. Biochem. 63, 595--602) for Coomassie Blue and adapted by Medugorac (Medugorac, I. (1979) Basic Res. Cardiol. 74, 406--416) for use with proteins stained with Fast Green FCF. The elution of dye from stained protein was accomplished using 1.0 M NaOH instead of aqueous pyridine as required by the original method. The primary advantages of our modification are that the time required for protein quantitation has been considerably reduced and the use of toxic organic solvents has been eliminated. We have investigated the applicability of the method of several different proteins and our results indicate: (a) The quantity of Fast Green FCF eluted from specific proteins is proportional to the quantity of protein applied to the gel, but varies for each individual protein. (b) The method allows quantitation over a very wide range of protein (1--800 micrograms). (c) Quantitation of protein is independent of the width of the stained bands as well as acrylamide concentration. (d) The method is applicable to gels of many types including disc, slab and continuous gradient gels. (e) Protein can be estimated from the patterns obtained by two-dimensional polyacrylamide gel electrophoresis. (f) The presence of Triton X-100 in gel and protein sample does not affect quantitation; the method is applicable to gels containing SDS provided that SDS is removed prior to staining. (g) Precipitation of protein with 12.5% TCA following electrophoresis does not interfere with quantitation. (h) The reproducibility of the technique is excellent, with standard deviations being less than 10% of the mean in all cases. This method appears highly versatile but requires appropriate standards for the quantitation of individual proteins. PMID:7276424

  14. Stents Eluting 6-Mercaptopurine Reduce Neointima Formation and Inflammation while Enhancing Strut Coverage in Rabbits

    PubMed Central

    Ruiter, Matthijs S.; van Tiel, Claudia M.; Doornbos, Albert; Marinković, Goran; Strang, Aart C.; Attevelt, Nico J. M.; de Waard, Vivian; de Winter, Robbert J.; Steendam, Rob; de Vries, Carlie J. M.

    2015-01-01

    Background The introduction of drug-eluting stents (DES) has dramatically reduced restenosis rates compared with bare metal stents, but in-stent thrombosis remains a safety concern, necessitating prolonged dual anti-platelet therapy. The drug 6-Mercaptopurine (6-MP) has been shown to have beneficial effects in a cell-specific fashion on smooth muscle cells (SMC), endothelial cells and macrophages. We generated and analyzed a novel bioresorbable polymer coated DES, releasing 6-MP into the vessel wall, to reduce restenosis by inhibiting SMC proliferation and decreasing inflammation, without negatively affecting endothelialization of the stent surface. Methods Stents spray-coated with a bioresorbable polymer containing 0, 30 or 300 μg 6-MP were implanted in the iliac arteries of 17 male New Zealand White rabbits. Animals were euthanized for stent harvest 1 week after implantation for evaluation of cellular stent coverage and after 4 weeks for morphometric analyses of the lesions. Results Four weeks after implantation, the high dose of 6-MP attenuated restenosis with 16% compared to controls. Reduced neointima formation could at least partly be explained by an almost 2-fold induction of the cell cycle inhibiting kinase p27Kip1. Additionally, inflammation score, the quantification of RAM11-positive cells in the vessel wall, was significantly reduced in the high dose group with 23% compared to the control group. Evaluation with scanning electron microscopy showed 6-MP did not inhibit strut coverage 1 week after implantation. Conclusion We demonstrate that novel stents coated with a bioresorbable polymer coating eluting 6-MP inhibit restenosis and attenuate inflammation, while stimulating endothelial coverage. The 6-MP-eluting stents demonstrate that inhibition of restenosis without leaving uncovered metal is feasible, bringing stents without risk of late thrombosis one step closer to the patient. PMID:26389595

  15. Acute ischemic cholecystitis after transarterial chemoembolization with drug-eluting beads.

    PubMed

    Karaman, Bülent; Battal, Bilal; Ören, Nisa Cem; Üstünsöz, Bahri; Yağci, Gökhan

    2012-01-01

    Transarterial chemoembolization (TACE) is a widely used treatment choice for hepatocellular cancer. DC Bead microspheres are a new embolic material for TACE that doxorubicin can be loaded to. The tumor response rate of this well-tolerated treatment was changed between 60% and 81.8%. We report a case of ischemic cholecystitis after TACE with drug-eluting beads (DEB) that required cholecystectomy. The possibility of cholecystitis is always remembered during TACE-DEB for tumors in segment IV and/or V. Although selective catheterization is related with a lower risk for ischemic cholecystitis, the anatomic and vascular variability in patients with malignancy may lead to some unexpected conditions. PMID:23154025

  16. Solid phase extraction and HPLC analysis of toxic components eluted from methyl methacrylate dental materials.

    PubMed

    Shintani, H; Tsuchiya, T; Hata, Y; Nakamura, A

    1993-01-01

    Methyl methacrylate polymer (PolyMMA) is widely used as the composite resin for the dental plate. During the fabrication process of PolyMMA for the polymerization reaction, benzoylperoxide (BPO) and N,N-dimethyl p-toluidine (DMPT) are added as the initiator and the stimulator, respectively. Because these compounds exhibit toxicity as well as a residue potential, their use raises concerns regarding human safety. The degree of dissolution into serum was determined to evaluate risk to the user. Analysis was by HPLC combined with solid-phase extraction using a C-18 column. The eluted compounds were found to be in the order of 10 to 100 ppm. PMID:8492570

  17. Bradycardia Associated With Drug-Eluting Beads Loaded With Irinotecan (DEBIRI) Infusion for Colorectal Liver Metastases

    SciTech Connect

    Pua, Uei

    2013-06-15

    Intra-arterial injection of drug-eluting beads loaded with irinotecan (DEBIRI) is a new treatment option being investigated, with encouraging results, for unresectable colorectal liver metastases that are refractory to systemic chemotherapy (Martin et al., Ann Surg Oncol 18:192-198, 2011). Toxicity related to DEBIRI has also been described (Martin et al., Cardiovasc Intervent Radiol 33:960-966, 2010). Nevertheless, experience and literature related to DEBIRI remain limited, and experience with this treatment is expected to increase. The purpose of this article is to describe bradycardia occurring during DEBIRI administration, which has not been reported thus far.

  18. Optimization of hydrophobic interaction chromatography using a mathematical model of elution curves of a protein mixture.

    PubMed

    Lienqueo, María Elena; Shene, Carolina; Asenjo, Juan

    2009-01-01

    This paper describes a methodology for optimizing performance of hydrophobic interaction chromatography (HIC) for protein mixtures in which Rate Model simulations and evaluation of cost function are used. The system under study was HIC of a two-protein mixture (alpha-chymotrypsin and alpha-amylase), carried out with different conditions (gradient steepness, salt, concentration, volume of sample, pH, type of matrix, and flow rates). Parameters in the rate model were obtained from different sources. Mass transfer parameters (Reynolds, Peclet, and Biot numbers) were calculated using empirical correlations. Under the experimental conditions Re number was small (0.23) and axial dispersion negligible (PeL>300). Mass transfer was controlled by intraparticle diffusion (Bi>50). The model assumes that equilibrium constant (b) in the Langmuir isotherm was salt concentration (I) dependent [b(I)]. Parameters in the relationship for b(I) were estimated from experimental single protein elution curves and used to simulate protein mixtures. Rate model simulations showed that if protein sample load to the column was below 1 mg, displacement effects were negligible; in other cases protein interactions would limit the proposed mathematical description of HIC. The calibrated Rate Model successfully predicted elution curves of the protein mixture with deviations lower than 6x10(-4) absorbance units. The model was also able to predict that the Butyl Sepharose--NaCl 4 M system allowed to obtain the highest resolution (>1) for the two-protein mixture evaluated. The cost function built for optimizing the performance of HIC considers yield, purity, concentration, and the time needed to accomplish the separation. This function contains two types of parameters that have to be determined. The ones dependent on the HIC system and process conditions were obtained from simulations of elution curves of the two-protein mixture, by the calibrated Rate Model. The other parameters are dependent on

  19. Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

    NASA Astrophysics Data System (ADS)

    Kumar, Sachin; Chatterjee, Kaushik

    2015-01-01

    The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium

  20. Economic analysis of endovascular drug-eluting treatments for femoropopliteal artery disease in the UK

    PubMed Central

    Katsanos, Konstantinos; Garner, Abigail M; Zayed, Hany; Cleveland, Trevor; Pietzsch, Jan B

    2016-01-01

    Objectives To estimate the clinical and economic impact of drug-eluting endovascular treatment strategies for femoropopliteal artery disease compared with current standard of care. Design Systematic literature search to pool target lesion revascularisations (TLR). Model-based per-patient cost impact and quasi-cost-effectiveness projection over 24 months based on pooled TLRs and current reimbursement. Setting The UK's National Health Service (NHS). Participants Patients presenting with symptomatic femoropopliteal disease eligible for endovascular treatment. Interventions Current National Institute for Health and Care Excellence (NICE) guideline-recommended treatment with percutaneous transluminal balloon angioplasty (PTA) and bailout bare metal stenting (BMS) versus primary BMS placement, or drug-coated balloon (DCB), or drug-eluting stent (DES) treatment. Primary and secondary outcome measures 24-month per-patient cost impact to NHS (primary outcome). Secondary outcomes: pooled 24-month TLR rates; numbers needed to treat (NNTs); cost per TLR avoided and estimated incremental cost-effectiveness ratio (ICER) in £ per quality-adjusted life year (QALY). Results N=28 studies were identified, reporting on 5167 femoropopliteal lesions. Over 24 months, DCB, DES and BMS reduced TLRs of de novo lesions from 36.2% to 17.6%, 19.4% and 26.9%, respectively, at an increased cost of £43, £44 and £112. NNTs to avoid 1 TLR in 24 months were 5.4, 6.0 and 10.8, resulting in cost per TLR avoided of £231, £264 and £1204. DCB was estimated to add 0.011 QALYs, DES 0.010 QALYs and BMS 0.005 QALYs, resulting in estimated ICERs of £3983, £4534 and £20 719 per QALY gained. A subset analysis revealed more favourable clinical and economic outcomes for a 3.5 µg/mm2 DCB with urea excipient, compared with the rest of DCBs. A modest reduction of 10% in DCB and DES prices made drug-eluting treatments dominant. Conclusions Widespread adoption of drug-eluting endovascular

  1. Vasculitis resulting from a superficial femoral artery angioplasty with a paclitaxel-eluting balloon.

    PubMed

    Thomas, Shannon D; McDonald, Robert R A; Varcoe, Ramon L

    2014-02-01

    Drug-eluting balloons (DEBs) coated with the antiproliferative agent paclitaxel may improve primary patency by reducing recurrent luminal stenosis. A proportion of the active drug and excipient coating are known to embolize distally, but until now, there have been no reports of adverse events resulting from their use. We report an unusual case of a painful nodular, biopsy specimen-proven vasculitic rash that afflicted the ipsilateral lower limb of a patient after superficial femoral artery treatment with a DEB. This adverse event may have implications for the use of DEB in this and other vascular territories. PMID:23642919

  2. Adenosine-induced coronary vasospasm following drug-eluting stent implantation

    PubMed Central

    Matsumoto, Naoya; Nagao, Ken; Hirayama, Atsushi; Kasama, Shu

    2014-01-01

    We present the case of coronary vasospasm during adenosine stress in a patient with a prior drug-eluting stent implantation. The patient had a stent implantation in the left anterior descending coronary artery 3 years ago. Recently, he developed a chest pain and underwent adenosine stress myocardial perfusion single photon emission CT (SPECT). During the adenosine stress, he felt severe chest pain and ST elevation on electrocardiogram. An invasive coronary angiography showed no in-stent restenosis. This phenomenon deemed to be adenosine-induced coronary vasospasm after stent implantation. PMID:24518394

  3. Application of rotational atherectomy in the drug-eluting stent era

    PubMed Central

    Chen, Chun-Chi; Hsieh, I-Chang

    2013-01-01

    Rotational atherectomy (RA) was introduced in the interventional arena in 1988 as a dedicated device for calcified lesions. Due to the complexity of the technique, the development of alternative methods such as the cutting balloon procedure, and the high restenosis rate of subsequent bare metal stenting in long lesions, its use had later declined. However, with the increasing use of drug-eluting stents (DES) and the aggressive treatment of longer lesions, the number of procedure performed with RA has increased significantly again in recent years. In this article, we reviewed the application of RA in DES era. PMID:24133506

  4. Sirolimus-eluting stent fracture detection by three-dimensional optical coherence tomography.

    PubMed

    Okamura, Takayuki; Matsuzaki, Masunori

    2012-03-01

    Stent fracture has emerged as a complication of drug-eluting stent and is now recognized as contributing to in-stent restenosis and possibly stent thrombosis. Although optical coherence tomography (OCT) can detect stent fractures in the absence of circumference struts, it is challenging to visualize stent fractures with only cross-sectional OCT images. We describe two cases of restenosis with stent fracture detected by a novel three-dimensional OCT image reconstruction technique. This technique allows identification of a single stent fracture even in the absence of angiographic signs. PMID:21805594

  5. Sequential leaching of coal to investigate the elution of inorganic elements into coal extract (HyperCoal)

    SciTech Connect

    Lian Zhang; Toshimasa Takanohashi; Tetsuya Nakazato; Ikuo Saito; Hiroaki Tao

    2008-07-15

    Two Argonne premium coal samples, Illinois No. 6 (IL) and Wyodak-Anderson (WY), were extracted by 1-methynaphthalene for 1 h at 360{sup o}C and under 1 MPa nitrogen (cold) protection. Elution of inorganic elements into coal extracts as well as their chemistry has been mainly investigated. An indirect method for metallic speciation was employed by initially washing coal with a variety of acids. Subsequently, the washed coals as well as the respective raw coal were extracted. For a given metal, elution of its ion-exchangeable fraction was defined as the difference between its amounts eluted into the extracts of raw coal and acetic acid-washed coal. Elution of submicrometer discrete particles was defined as the difference between the extracts of acetic acid-washed coal and nitric acid-washed coal. Elution of its fraction insoluble in nitric acid was assigned as organometals which are chemically associated with coal carbonaceous matrix and/or those incorporated into fine clay minerals. About 822 and 1110 ppm inorganic elements were eluted into the extracts of IL and WY coals, respectively. Fe was the most prevalent. The transition metals including Cr, Ni, Mn, Co, Cu, and Zn were also abundant. These metals were mostly nitric-acid insoluble. Electron spin resonance spectroscopy characterization suggested the high-spin Fe{sup 3+} state for Fe that is virtually totally associated with coal functional groups. Regarding the remaining metals in coal extracts, they are mainly submicrometer discrete particles in IL extract. Elution of the ion-exchangeable carboxylates was however prominent during WY coal extraction. 43 refs., 6 figs., 5 tabs.

  6. Optical coherence tomographic observations of polytetrafluoroethylene-covered sirolimus-eluting coronary arterial stent.

    PubMed

    Hou, Jingbo; Jia, Haibo; Huang, Xingtao; Yu, Huai; Ren, Xuefeng; Fang, Yan; Han, Zhigang; Yang, Shuang; Meng, Lingbo; Zhang, Shaosong; Yu, Bo; Jang, Ik-Kyung

    2013-04-15

    The aim of this study was to evaluate neointimal coverage obtained using a new method of polytetrafluoroethylene-covered stent (PCS) implantation combined with underlying longer sirolimus-eluting stent (SES) implantation using optical coherence tomography. Nine patients were enrolled in this study, including patients with coronary artery perforations, original coronary aneurysms, and acquired coronary aneurysms after drug-eluting stent implantation. All patients were first treated with long SES implantation and then with focal PCS implantation. Postprocedural and follow-up angiographic and optical coherence tomographic examinations were performed in all patients, and intravascular ultrasound was performed in 5 patients. All patients were asymptomatic during follow-up, without recurrent angina. There was no stent-edge or stent-segment binary restenosis. Values of late loss for proximal SES segments, PCS segments, and distal SES segments were similar (0.09, 0.07, and 0.04 mm, respectively, p = 0.8113). The mean neointimal thickness of PCS was less than that of proximal and distal SES. However, no malapposed cross sections or uncovered cross sections were found in PCS segments compared with SES segments (p = 0.0011). In conclusion, the combination of PCS and underlying longer SES implantation can offer better angiographic follow-up results. High-resolution optical coherence tomography provided convincing proof of full neointimal coverage of PCS. This new method of combined PCS and SES implantation may be a better choice compared with direct PCS implantation in certain clinical settings. PMID:23351458

  7. Drug-eluting balloon catheters for lower limb peripheral arterial disease: the evidence to date

    PubMed Central

    Barkat, Mohamed; Torella, Francesco; Antoniou, George A

    2016-01-01

    A significant proportion of patients with severe lower limb peripheral arterial disease require revascularization. Over the past decade, an endovascular-first approach even for complex disease has gained widespread use among vascular specialists. An important limitation of percutaneous transluminal balloon angioplasty or stenting remains the occurrence of restenosis. Drug-coated balloons have emerged as an exciting technology developed to overcome the limitations of standard balloon angioplasty and stenting. Drug-eluting devices inhibit neointimal growth of vascular smooth muscle cells with the potential of preventing restenosis. This review provides a synopsis of the up-to-date evidence on the role of drug-coated balloons in the treatment of lower limb peripheral arterial disease. Bibliographic searches were conducted using MEDLINE, EMBASE, and the Cochrane Library electronic database. Eleven randomized clinical trials, two systematic reviews, and a published registry providing the best available evidence were identified. Current evidence suggests that angioplasty with drug-coated balloon is reliable, safe, and efficient in increasing patency rates and reducing target lesion revascularization and restenosis. However, it remains unknown whether these improved results can translate into beneficial clinical outcomes, as current randomized clinical trials have failed to demonstrate a significant benefit in limb salvage and mortality. Further randomized trials focusing on clinical and functional outcomes of drug-eluting balloons and on cost versus clinical benefit are required. PMID:27274265

  8. In vivo performance of a drug-eluting contact lens to treat glaucoma for a month

    PubMed Central

    Ciolino, Joseph B.; Stefanescu, Cristina F.; Ross, Amy E.; Salvador-Culla, Borja; Cortez, Priscila; Ford, Eden M.; Wymbs, Kate A.; Sprague, Sarah L.; Mascoop, Daniel R.; Rudina, Shireen S.; Trauger, Sunia A.; Cade, Fabiano; Kohane, Daniel S.

    2013-01-01

    For nearly half a century, contact lenses have been proposed as a means of ocular drug delivery, but achieving controlled drug release has been a significant challenge. We have developed a drug-eluting contact lens designed for prolonged delivery of latanoprost for the treatment of glaucoma, the leading cause of irreversible blindness worldwide. Latanoprost-eluting contact lenses were created by encapsulating latanoprost–poly(lactic-co-glycolic acid) films in methafilcon by ultraviolet light polymerization. In vitro and in vivo studies showed an early burst of drug release followed by sustained release for one month. Contact lenses containing thicker drug–polymer films demonstrated released a greater amount of drug after the initial burst. In vivo, single contact lenses were able to achieve, for at least one month, latanoprost concentrations in the aqueous humor that were comparable to those achieved with topical latanoprost solution, the current first-line treatment for glaucoma. The lenses appeared safe in cell culture and animal studies. This contact lens design can potentially be used as a treatment for glaucoma and as a platform for other ocular drug delivery applications. PMID:24094935

  9. Centrifugal partition chromatography elution gradient for isolation of sesquiterpene lactones and flavonoids from Anvillea radiata.

    PubMed

    Destandau, Emilie; Boukhris, Meryem Alaoui; Zubrzycki, Sandrine; Akssira, Mohamed; Rhaffari, Lhoucine El; Elfakir, Claire

    2015-03-15

    An innovative procedure coupling pressurized solvent extraction and centrifugal partition chromatography (CPC) used in linear gradient elution mode was developed to isolate two pure germacranolides (9α-hydroxyparthenolide and 9β-hydroxyparthenolide) and to separate flavonoids (nepetin, isorhamnetin and jaceosidin) and chlorophyll pigments from aerial parts of Anvillea radiata (Coss.&Durieu). The two main germacranolides recovered using this method represent 2 and 5% of the dried plant material respectively. These molecules were extracted using accelerated solvent extraction with chloroform. After optimization of the CPC method, a two-phase solvent system composed of heptane/ethyl acetate/methanol/water (1:5:1:5 v/v/v/v) was employed in descending mode to isolate the germacranolides. Then the lower phase of a heptane/ethyl acetate/methanol/water (6:5:6:5 v/v/v/v) system was pumped in descending mode to generate a linear elution gradient, progressively decreasing the mobile phase polarity, that enabled the flavonoid compounds to be separated in the same run. The efficiency of the preparative separation was controlled through RP-HPLC analysis of the obtained fractions using UV, evaporative light scattering and mass spectrometry detection. The structural identification of the two germacranolides purified over 99% was established by (1)H NMR and (13)C NMR. The least abundant flavonoids were identified by mass spectrometry. PMID:25647341

  10. Effect of Food Stimulated Liquids and Thermocycling on the Monomer Elution from a Nanofilled Composite

    PubMed Central

    Tabatabaei, Masumeh Hasani; Sadrai, Sima; Bassir, Seyed Hossein; Veisy, Nadia; Dehghan, Somaye

    2013-01-01

    The present study was aimed to evaluate the effects of food simulating liquids and thermocycling on the elution of monomers from a nanofilled resin composite in different immersion times. Five Specimen discs were made from a nano-hybrid composite (Supreme 3M) for each group (Total = 180) and immersed in distilled water (control), citric acid, lactic acid, and 75% aqueous ethanol solution. The discs were removed after 24 h, 48 h, 72 h, 1 wk, 4 wk, and 12 wk. Three groups of samples underwent thermocycling for 1000, 2000 and 3000 cycles. The solutes were analyzed with HPLC for detection of eluted monomers. The results showed that the amount of released TEGDMA was significantly higher than that of Bis-GMA; however, there were not any significant differences between the amount of released Bis-GMA and UDMA. Moreover, the highest amount of monomers was released from samples immersed in ethanol solution; samples immersed in citric acid and lactic acid significantly released more monomers than those immersed in distilled water. Furthermore, the immersion time in aqueous ethanol solution had an increasing effect on the release of monomers. In addition, the higher amounts of monomers were release from samples immersed in ethanol and citric acid which underwent a higher number of thermal cycles. In conclusion, food and drink stimulated liquids used in this study increased the amount of some of the monomers released from composite resin. Thermal shocks and storage time are other factors that increased the release of monomers from the composite resin PMID:23986791

  11. Effect of pH on phosphorus, copper, and zinc elution from swine wastewater activated sludge.

    PubMed

    Waki, Miyoko; Yasuda, Tomoko; Fukumoto, Yasuyuki; Suzuki, Kazuyoshi

    2014-01-01

    With the goal of reducing the amounts of phosphorus (P), copper (Cu), and zinc (Zn) discharged from swine wastewater activated sludge treatment facilities, we studied the elution of these elements from activated sludge at various pH values. Sludge samples with neutral pH collected from three farms were incubated at pH values ranging from 3 to 10. The soluble concentrations of these elements changed dramatically with pH and were highest at pH 3. We assumed that P present in the sludge under neutral and alkaline conditions was in insoluble form bound up with magnesium (Mg) and calcium (Ca), because Ca and Mg also eluted from the sludge at low pH. To clarify forms of Zn and Cu in the sludge, we performed a sequential extraction analysis. Zinc in adsorbed, organically bound, and sulfide fractions made up a large proportion of the total Zn. Copper in organically bound, carbonate, and sulfide fractions made up a large proportion of the total Cu. The soluble P concentrations were lowest at pH 9 or 10 (11-36 mg/L), the soluble Zn concentrations were lowest at pH 8 or 9 (0.07-0.15 mg/L), and the soluble Cu concentrations were lowest at pH 6-9 (0.2 mg/L, the detection limit). PMID:25116486

  12. Drug-eluting Ti wires with titania nanotube arrays for bone fixation and reduced bone infection

    NASA Astrophysics Data System (ADS)

    Gulati, Karan; Aw, Moom Sinn; Losic, Dusan

    2011-10-01

    Current bone fixation technology which uses stainless steel wires known as Kirschner wires for fracture fixing often causes infection and reduced skeletal load resulting in implant failure. Creating new wires with drug-eluting properties to locally deliver drugs is an appealing approach to address some of these problems. This study presents the use of titanium [Ti] wires with titania nanotube [TNT] arrays formed with a drug delivery capability to design alternative bone fixation tools for orthopaedic applications. A titania layer with an array of nanotube structures was synthesised on the surface of a Ti wire by electrochemical anodisation and loaded with antibiotic (gentamicin) used as a model of bone anti-bacterial drug. Successful fabrication of TNT structures with pore diameters of approximately 170 nm and length of 70 μm is demonstrated for the first time in the form of wires. The drug release characteristics of TNT-Ti wires were evaluated, showing a two-phase release, with a burst release (37%) and a slow release with zero-order kinetics over 11 days. These results confirmed our system's ability to be applied as a drug-eluting tool for orthopaedic applications. The established biocompatibility of TNT structures, closer modulus of elasticity to natural bones and possible inclusion of desired drugs, proteins or growth factors make this system a promising alternative to replace conventional bone implants to prevent bone infection and to be used for targeted treatment of bone cancer, osteomyelitis and other orthopaedic diseases.

  13. The everolimus-eluting Xience stent in small vessel disease: bench, clinical, and pathology view

    PubMed Central

    Sanchez, Oscar D; Yahagi, Kazuyuki; Koppara, Tobias; Virmani, Renu; Joner, Michael

    2015-01-01

    Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. The pathogenesis of CAD relates to the presence of atherosclerotic plaques in the coronary arteries, which are most frequently treated today by percutaneous coronary intervention. Small vessel disease treatment represents one-third of all percutaneous coronary interventions with higher rates of restenosis and major adverse cardiac events. Initially, drug-eluting stents (DES) were developed to reduce in-stent restenosis, improving clinical outcomes and reducing the need for target vessel revascularization. However, late and very late stent thrombosis emerged as a new problem compromising DES’s long-term results. The cobalt–chromium everolimus-eluting stent (CoCr-EES) represents the results of an evolutionary process in DES technology aimed at improving the shortcomings of first-generation DES. Small vessel CAD has historically been an obstacle to long-term patency following implantation of DES. Antirestenotic efficacy has been shown to be of high relevance in small vessels. Therefore, stent selection may play an important role in determining outcomes in this subgroup of patients. This article will review the performance of CoCr-EES in the treatment of small vessel CAD from preclinical, clinical, and pathology perspectives, and it will highlight the most important findings in this regard. PMID:25565907

  14. Effect of energetic materials wettability on their outdoor effective elution rate.

    PubMed

    Lapointe, Marie-Claude; Martel, Richard; Lange, Sébastien F; Coté, Sébastien

    2016-07-01

    Energetic materials (EM) contained in military ammunitions have been found in the surface soil and water of training areas and may potentially represent a threat to human health and the environment. EM wettability is an essential physical parameter to characterize because it controls EM dissolution rate. This paper was conducted to determine the wettability of conventional and new EM formulations used in military ammunition. Wettability was estimated in the laboratory via contact angle measurements of water droplets on different EM surfaces. Results show that 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), Octol and energetic thermoplastic elastomer (ETPE) 1000 are hydrophilic while Composition B, XRT, GIM, CX-85, ETPE 2000, and C4 are hydrophobic whereas HELOVA gun propellant has a mixed wettability oscillating between hydrophilic and hydrophobic. The present study demonstrates that wettability of EM formulation is generally controlled by their matrix constituents. Results indicate that hydrophobic formulations have a much slower outdoor environmental effective elution rate than hydrophilic ones, with the exception of the hydrophobic C4 formulation whose elution rate is extremely high. The addition of hydrophobic components into EM formulations is recommended to diminish the environmental impact on water, as it has already been done with XRT, GIM and CX-85 formulations. PMID:26985872

  15. Nanoparticle Drug- and Gene-eluting Stents for the Prevention and Treatment of Coronary Restenosis

    PubMed Central

    Yin, Rui-Xing; Yang, De-Zhai; Wu, Jin-Zhen

    2014-01-01

    Percutaneous coronary intervention (PCI) has become the most common revascularization procedure for coronary artery disease. The use of stents has reduced the rate of restenosis by preventing elastic recoil and negative remodeling. However, in-stent restenosis remains one of the major drawbacks of this procedure. Drug-eluting stents (DESs) have proven to be effective in reducing the risk of late restenosis, but the use of currently marketed DESs presents safety concerns, including the non-specificity of therapeutics, incomplete endothelialization leading to late thrombosis, the need for long-term anti-platelet agents, and local hypersensitivity to polymer delivery matrices. In addition, the current DESs lack the capacity for adjustment of the drug dose and release kinetics appropriate to the disease status of the treated vessel. The development of efficacious therapeutic strategies to prevent and inhibit restenosis after PCI is critical for the treatment of coronary artery disease. The administration of drugs using biodegradable polymer nanoparticles as carriers has generated immense interest due to their excellent biocompatibility and ability to facilitate prolonged drug release. Despite the potential benefits of nanoparticles as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of nanoparticle materials, as well as to their size and shape. This review describes the molecular mechanism of coronary restenosis, the use of DESs, and progress in nanoparticle drug- or gene-eluting stents for the prevention and treatment of coronary restenosis. PMID:24465275

  16. Characterizing and modeling of extensive atrazine elution tailing for stable manure-amended agricultural soil.

    PubMed

    Akyol, Nihat Hakan

    2015-01-01

    Non-ideal sorption and extensive elution tailing behavior of atrazine was evaluated for an agricultural soil with and without stable manure amendment (10% by weight). A series of laboratory experiments showed that the sorption of atrazine was described by rate-limited, nonlinear reversible processes (Freundlich isotherm) for both non-amended and amended soil. Non-ideal transport of atrazine exhibited extensive low concentration elution tailing due to the most likely organic carbon fraction in the soil. This tailing behavior was more pronounced and extensive for soil with 10% stable-manure amendment. Two-site transport modeling analyses including non-linear sorption and rate-limited sorption-desorption provided a reasonably good match to the atrazine breakthrough curves but were unable to match the long-term concentration tailing, even for non-amended soil. A mathematical model incorporating nonlinear, rate-limited sorption/desorption described by a continuous-distribution function was used to successfully simulate atrazine transport early-time breakthrough and long-term concentration tailing for both non-amended and amended soil conditions. PMID:25303664

  17. Usefulness of Everolimus-Eluting Coronary Stent Implantation in Patients on Maintenance Hemodialysis.

    PubMed

    Ikari, Yuji; Kyono, Hiroyuki; Isshiki, Takaaki; Ishizuka, Shuichi; Nasu, Kenya; Sano, Koichi; Okada, Hisayuki; Sugano, Teruyasu; Uehara, Yoshiki

    2015-09-15

    The outcomes of second-generation drug-eluting stent (DES) are unknown in patients on maintenance hemodialysis (HD) although HD has been reported as a strong predictor of adverse outcome after the first-generation DES implantation. The OUCH-PRO Study is a prospective multicenter single-arm registry design to study clinical and angiographic outcomes after everolimus-eluting stent (EES). Patients who underwent maintenance HD were prospectively enrolled at the time of elective coronary intervention using EES. Quantitative coronary angiography was performed in an independent core laboratory. The primary end point was the occurrence of target vessel failure (TVF) defined as cardiac death, myocardial infarction (MI), and target vessel revascularization at 1 year. A total of 123 patients were enrolled and 161 EES were implanted. The TVF rate at 1 year was 18% (4% cardiac death, 0% MI, 17% target vessel revascularization). No stent thrombosis was documented. Other clinical events at 1 year were 3% noncardiac death, 3% stroke, and 9% non-target-vessel revascularization. Late lumen loss in stent was 0.37 ± 0.63 mm at 8 months. In conclusion, EES had a high TVF rate and great late lumen loss in patients on HD compared with previous huge EES data in non-HD patients. PMID:26219496

  18. Preparation, degradation and in vitro release of ciprofloxacin-eluting ureteral stents for potential antibacterial application.

    PubMed

    Ma, Xiaofei; Xiao, Yan; Xu, Heng; Lei, Kun; Lang, Meidong

    2016-09-01

    Drug-eluting stents with biodegradable polymers as reservoirs have shown great potential in the application of interventional therapy due to their capability of local drug delivery. Herein, poly(l-lactide-co-ε-caprolactone) (PLCL) with three different compositions as carriers for ciprofloxacin lactate (CIP) was coated on ureteral stents by the dipping method. To simulate a body environment, degradation behavior of PLCL as both the bulk film and the stent coating was evaluated in artificial urine (AU, pH6.20) respectively at 37°C for 120days by tracing their weight/Mn loss, water absorption and surface morphologies. Furthermore, the release profile of the eluting drug CIP on each stent exhibited a three-stage pattern, which was greatly affected by the degradation behavior of PLCL except for the burst stage. Interestingly, the degradation results on both macroscopic and molecular level indicated that the release mechanism at stage I was mainly controlled by chain scission instead of the weight loss or morphological changes of the coatings. While for stage II, the release profile was dominated by erosion resulting from the hydrolysis reaction autocatalyzed by acidic degradation residues. In addition, ciprofloxacin-loaded coatings displayed a significant bacterial resistance against E. coli and S. aureus without obvious cytotoxicity to Human foreskin fibroblasts (HFFs). Our results suggested that PLCL copolymers with tunable degradation rate as carriers for ciprofloxacin lactate could be used as a promising long-term antibacterial coating for ureteral stents. PMID:27207042

  19. Overcoming the high-temperature two-dimensional gas chromatography limits to elute heavy compounds.

    PubMed

    Mahé, Laure; Courtiade, Marion; Dartiguelongue, Cyril; Ponthus, Jérémie; Souchon, Vincent; Thiébaut, Didier

    2012-03-16

    Overcoming high-temperature (HT) two-dimensional gas chromatography (GC × GC) limits is critical for the analysis of heavy hydrocarbons, particularly those contained in heavy petroleum fractions. To reach this goal, HT-GC × GC analysis was adapted from HT-GC Simulated Distillation (HT-GC SimDist) operating conditions as this analysis embraces compounds whose boiling point ranges from 35 °C to 700 °C and from a previous study that enabled the elution of linear alkane nC(60) and tetraaromatic compounds by HT-GC × GC. This paper shows that HT-GC × GC analysis using CO(2) cryogenic modulator and short wide bore columns with a thin film of stationary phase allows the elution of linear alkanes up to nC(68) (641 °C) as well as of highly aromatic hydrocarbons like coronene. Furthermore, compared to previous studies, an on-column injector was used to reduce discrimination of high boiling point compounds. PMID:22307150

  20. Numerical modeling of the elution peak profiles of retained solutes in supercritical fluid chromatography

    SciTech Connect

    Kaczmarski, Krzysztof; Guiochon, Georges A

    2011-01-01

    In supercritical fluid chromatography (SFC), the significant expansion of the mobile phase along the column causes the formation of axial and radial gradients of temperature. Due to these gradients, the mobile phase density, its viscosity, its velocity, its diffusion coefficients, etc. are not constant throughout the column. This results in a nonuniform flow velocity distribution, itself causing a loss of column efficiency in certain cases, even at low flow rates, as they do in HPLC. At high flow rates, an important deformation of the elution profiles of the sample components may occur. The model previously used to account satisfactorily for the retention of an unsorbed solute in SFC is applied to the modeling of the elution peak profiles of retained compounds. The numerical solution of the combined heat and mass balance equations provides the temperature and the pressure profiles inside the column and values of the retention time and the band profiles of retained compounds that are in excellent agreement with independent experimental data for large value of mobile phase reduced density. At low reduced densities, the band profiles can strongly depend on the column axial distribution of porosity.

  1. Stent thrombosis with drug-eluting stents: is the paradigm shifting?

    PubMed

    Palmerini, Tullio; Biondi-Zoccai, Giuseppe; Della Riva, Diego; Mariani, Andrea; Genereux, Philippe; Branzi, Angelo; Stone, Gregg W

    2013-11-19

    First-generation drug-eluting stents (DES), which impart the controlled release of sirolimus or paclitaxel from durable polymers to the vessel wall, have been consistently shown to reduce the risk of restenosis and target vessel revascularization compared with bare metal stents (BMS). However, stent thrombosis (ST) emerged as a major safety concern with first-generation DES early after their adoption in clinical practice, requiring prolonged dual antiplatelet therapy. Pathological studies have shown that first-generation DES are associated with delayed arterial healing and polymer hypersensitivity reactions resulting in chronic inflammation, predisposing to late and very late ST. Second-generation DES have been developed to overcome these issues with improved stent designs and construction and the use of biocompatible and bioabsorbable polymers. Meta-analyses have shown that the thin-strut, fluoropolymer-coated cobalt-chromium everolimus-eluting stent (CoCr-EES) may be associated with lower rates of definite ST than other DES and, unexpectedly, even lower than BMS. The thin-strut structure of the stent platform, the thromboresistant properties of the fluoropolymer, and the reduced polymer and drug load may contribute to the low rate of ST with CoCr-EES. The notion of DES being safer than BMS represents a paradigm shift in the evolution of percutaneous coronary intervention. The relative safety and efficacy of fluoropolymer-coated CoCr-EES, DES with bioabsorbable polymers, and fully bioresorbable scaffolds are the subject of numerous ongoing large-scale trials. PMID:24036025

  2. Peak Capacity Optimization of Peptide Separations in Reversed-Phase Gradient Elution Chromatography

    PubMed Central

    Wang, Xiaoli; Stoll, Dwight R; Schellinger, Adam P; Carr, Peter W.

    2008-01-01

    The optimization of peak capacity in gradient elution RPLC is essential for the separation of multi-component samples such as those encountered in proteomic research. In this work we study the effect of gradient time (tG), flow rate (F), temperature (T) and final eluent strength (ϕfinal) on the peak capacity of separations of peptides that are representative of the range in peptides found in a tryptic digest. We find that there are very strong interactions between the individual variables (e.g. flow rate and gradient time) which make the optimization quite complicated. On a given column, one should first set the gradient time to the longest tolerable and then set the temperature to the highest achievable with the instrument. Next, the flow rate should be optimized using a reasonable but arbitrary value of ϕfinal. Last, the final eluent strength should be adjusted so that the last solute elutes as close as possible to the gradient time. We also develop an easily implemented, highly efficient and effective Monte Carlo search strategy to simultaneously optimize all the variables. We find that gradient steepness is an important parameter that influences peak capacity and an optimum range of gradient steepness exists in which the peak capacity is maximized. PMID:16689544

  3. New drug-eluting lenses to be applied as bandages after keratoprosthesis implantation.

    PubMed

    Carreira, A S; Ferreira, P; Ribeiro, M P; Correia, T R; Coutinho, P; Correia, I J; Gil, M H

    2014-12-30

    Corneal tissue is the most commonly transplanted tissue worldwide. This work aimed to develop a new drug-eluting contact lens that may be used as a bandage after keratoprosthesis. During this work, films were produced using poly(vinyl alcohol) (PVA) and chitosan (CS) crosslinked with glyoxal (GL). Vancomycin chlorhydrate (VA) was impregnated in these systems by soaking. Attenuated total reflectance - Fourier transform infrared spectroscopy was used to confirm crosslinking. The cytotoxic and drug release profile, hydrophilicity, thermal and biodegradation as well as swelling capacity of the samples were assessed through in vitro studies. PVA and PVA/CS films were obtained by crosslinking with GL. The films were transparent, flexible with smooth surfaces, hydrophilic and able to load and release vancomycin for more than 8h. Biodegradation in artificial lachrymal fluid (ALF) with lysozyme at 37°C showed that mass loss was higher for the samples containing CS. Also, the samples prepared with CS showed the formation of pores which were visualized by SEM. All samples revealed a biocompatible character after 24h in contact with cornea endothelial cells. As a general conclusion it was possible to determine that the 70PVA/30CS film showed to combine the necessary features to prepare vancomycin-eluting contact lenses to prevent inflammation after corneal substitution. PMID:25455772

  4. Serial gray scale intravascular ultrasound findings in late drug-eluting stent restenosis.

    PubMed

    Hakim, Diaa A; Mintz, Gary S; Sanidas, Elias; Rusinova, Reni; Weisz, Giora; Leon, Martin B; Moses, Jeffery W; Stone, Gregg W; Maehara, Akiko

    2013-03-01

    The primary aim of the present study was to assess the gray scale intravascular ultrasound (IVUS) findings that might be associated with late drug-eluting stent restenosis. The study included 47 patients (54 lesions) who had undergone either baseline IVUS-guided stent implantation or IVUS-guided repeat stenting to treat in-stent restenosis and then had IVUS follow-up data for ≥1.5 years afterward without any intervening procedures. The left anterior descending artery was the culprit in 59% of cases, and 50% of the lesions were at bifurcation sites. Quantitative and qualitative IVUS analyses showed a decreased minimum lumen area at follow-up from 6.0 ± 1.8 to 3.8 ± 1.4 mm(2) (p <0.0001) that was mainly due to neointimal hyperplasia with chronic stent recoil (defined as a >15% decrease in minimum stent area) in only 2 lesions and stent fracture in only 5 lesions. Calcified neointima appeared in 12 lesions, mostly in the form of macrocalcification, and was associated with increased calcium both behind the stent and in the reference segment. In conclusion, late drug-eluting stent restenosis showed neointimal calcification in 20% of cases, and chronic stent recoil was rare. PMID:23273714

  5. [Two steps elution method FI on-line adsorption and preconcentration coupled with FAAS for the determination of trace zinc].

    PubMed

    Wang, Zhong-yuan; Zhang, Hong-kang; Fang, Hong-da; Su, Yao-dong; Mittal, Gauri S

    2011-12-01

    A flow injection two steps elution method on-line sorption and preconcentration system coupled to flame atomic absorption spectrometry (FAAS) was developed for the determination of trace Zn in water samples. The conventional elution procedure was divided into two steps: elution procedure and detection procedure. During the elution procedure, the eluent was pumped into KR by the suction of the peristaltic pump and through PTFE tube instead of peristaltic pump tube. By the new method, the dispersion of the analyte was decreased notably, and high absorbance peak value was achieved. Because the eluent was not through the peristaltic pump tube, the peristaltic pump tube was protected from being eroded. Emptying procedure was added in order to insure the veracity and repeatability of the experiment of every time. With 60 s (sample throughput of 37 x h(-1)) of sampling at a flow rate of 6.0 mL x min(-1), an enhancement factor (EF) of 28 (higher than 9 achieved by conventional elution method) and a detection limit (3sigma) of 0.35 x L(-1) were obtained. The precision (RSD, n=11) was 2.1% at the 20 microg x L(-1) level. When 0.1% phi triethannolamine was used as masking reagent, the recovery rate was from 98.7% to 99.6%. PMID:22295800

  6. Evaluation of the Effectiveness of Surfactants and Denaturants to Elute and Denature Adsorbed Protein on Different Surface Chemistries.

    PubMed

    Thyparambil, Aby A; Wei, Yang; Latour, Robert A

    2015-11-01

    The elution and/or denaturation of proteins from material surfaces by chemical excipients such as surfactants and denaturants is important for numerous applications including medical implant reprocessing, bioanalyses, and biodefense. The objective of this study was to develop and apply methods to quantitatively assess how surface chemistry and adsorption conditions influence the effectiveness of three commonly used surfactants (sodium dodecyl sulfate, n-octyl-β-d-glucoside, and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) and two denaturants (guanidium hydrochloride and urea) to elute protein (hen egg white lysozyme and bovine pancreatic ribonuclease A) from three different surface chemistries (silica glass, poly(methyl methacrylate), and high-density polyethylene). The structure and bioactivity of residual protein on the surface following elution were characterized using circular dichroism spectropolarimetry and enzyme assays to assess the extent of protein denaturation. Our results indicate that the denaturants were generally more effective than the surfactants in removing the adsorbed proteins from each type of surface. Also, the denaturing capacity of these excipients on the residual proteins on the surfaces was distinctly different from their influence on the proteins in solution and was unique for each of the adsorption conditions. Taken altogether, these results reveal that the effectiveness of surfactants and denaturants to elute and denature adsorbed protein is significantly influenced by surface chemistry and the conditions from which the protein was adsorbed. These results provide a basis for the selection, design, and further development of chemical agents for protein elution and surface decontamination. PMID:26449787

  7. Development of Online pH Gradient-Eluted Strong Cation Exchange Nanoelectrospray-Tandem Mass Spectrometry for Proteomic Analysis Facilitating Basic and Histidine-Containing Peptides Identification.

    PubMed

    Xu, Jingjing; Gao, Jing; Yu, Chengli; He, Han; Yang, Yiming; Figeys, Daniel; Zhou, Hu

    2016-01-01

    A novel one-dimensional online pH gradient-eluted strong cation exchange-nanoelectrospray ionization-tandem mass spectrometry (SCX-nano-ESI-MS/MS) method was developed for protein identification and tested with a mixture of six standard proteins, total lysate of HuH7 and N2a cells, as well as membrane fraction of N2a cells. This method utilized an online nanoflow SCX column in a nano-LC system coupled with a nanoelectrospray high-resolution mass spectrometer. Protein digests were separated on a nanoflow SCX column with a pH gradient and directly introduced into a mass spectrometer through nanoelectrospray ionization. More than five thousand unique peptides were identified in each 90 min LC-MS/MS run using 500 nanogram of protein digest either from total cell lysate or from membrane fraction. The unique peptide overlap between online strong cation exchange nano-ESI-MS/MS (SCXLC-MS/MS) and reverse phase nano-ESI-MS/MS (RPLC-MS/MS) is only ≤30%, which indicated these two methods were complementary to each other. The correlation coefficient of retention time and theoretical isoelectric point (pI) of identified peptides in SCXLC-MS/MS was higher than 0.4, which showed that peptides elution in SCXLC-MS/MS was dependent on their charge states. Furthermore, SCXLC-MS/MS showed identification capability for a higher proportion of basic peptides compared to the RPLC-MS/MS method, especially for histidine-containing peptides. Our SCXLC-MS/MS method is an excellent alternative method to the RPLC-MS/MS method for analysis of standard proteins, total cell and membrane proteomes. PMID:26646553

  8. Lighting Utilization.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with lighting utilization. Its objective is for the student to be able to outline the development of lighting use and conservation and identify major types and operating characteristics of lamps used in electric lighting. Some topics…

  9. BIOMASS UTILIZATION

    EPA Science Inventory

    The biomass utilization task consists of the evaluation of a biomass conversion technology including research and development initiatives. The project is expected to provide information on co-control of pollutants, as well as, to prove the feasibility of biomass conversion techn...

  10. Comparison of the Efficacy of Everolimus-Eluting Stents Versus Drug-Eluting Balloons in Patients With In-Stent Restenosis (from the RIBS IV and V Randomized Clinical Trials).

    PubMed

    Alfonso, Fernando; Pérez-Vizcayno, María José; García Del Blanco, Bruno; García-Touchard, Arturo; Masotti, Mónica; López-Minguez, José R; Iñiguez, Andrés; Zueco, Javier; Velazquez, Maite; Cequier, Angel; Lázaro-García, Rosa; Martí, Vicens; Moris, César; Urbano-Carrillo, Cristobal; Bastante, Teresa; Rivero, Fernando; Cárdenas, Alberto; Gonzalo, Nieves; Jiménez-Quevedo, Pilar; Fernández, Cristina

    2016-02-15

    Treatment of patients with in-stent restenosis (ISR) remains a challenge. This study sought to compare the efficacy of everolimus-eluting stents (EESs) and drug-eluting balloons (DEBs) with paclitaxel in patients with ISR. A pooled analysis of the Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloon vs Everolimus-Eluting Stent (RIBS IV) and Restenosis Intra-Stent of Bare-Metal Stents: Drug-Eluting Balloon vs Everolimus-Eluting Stent (RIBS V) randomized trials was performed using patient-level data. In both trials, EESs were compared with DEBs in patients with ISR (RIBS V included 189 patients with bare-metal ISR; RIBS IV included 309 patients with drug-eluting ISR). Inclusion and exclusion criteria were identical in both trials. A total of 249 patients were allocated to EES and 249 to DEB. Clinical follow-up at 1 year was obtained in all (100%) patients and late angiography (median 249 days) in 91% of eligible patients. Compared with patients treated with DEBs, patients treated with EESs obtained better short-term results (postprocedural minimal lumen diameter 2.28 ± 0.5 vs 2.12 ± 0.4 mm, p <0.0001). At follow-up, patients treated with EESs had larger in-segment minimal lumen diameter (primary end point 2.16 ± 0.7 vs 1.88 ± 0.6 mm, p <0.0001; absolute mean difference 0.28 mm; 95% confidence interval [CI] 0.16 to 0.40) and net lumen gain (1.33 ± 0.6 vs 1.00 ± 0.7 mm, p <0.0001) and had lower %diameter stenosis (19 ± 21% vs 28 ± 22%, p <0.0001) and binary restenosis rate (8.7% vs 15.7%, p = 0.02). Consistent results were observed in the in-lesion analysis. No interactions were found between the underlying stent type and treatment effects. At 1-year clinical follow-up, the composite of cardiac death, myocardial infarction, and target vessel revascularization was significantly reduced in the EES arm (8.8% vs 14.5%, p = 0.03; hazard ratio 0.59, 95% CI 0.31 to 0.94) mainly driven by a lower need for target vessel revascularization (6% vs 12.4%, p