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22099656 | Application of chitosan/Fe₃O₄ microsphere-graphene composite modified carbon ionic liquid electrode for the electrochemical detection of the PCR product of soybean Lectin gene sequence. | In this paper a Fe(3)O(4) microsphere, graphene (GR) and chitosan (CTS) posite material modified carbon ionic liquid electrode (CILE) was used as the platform for the construction of a new electrochemical DNA biosensor. The single-stranded DNA (ssDNA) probe was immobilized directly on the surface of the CTS/Fe(3)O(4)-GR/CILE, which could hybridize with the target ssDNA sequence at the selected conditions. By using methylene blue (MB) as the electrochemical indicator the hybridization reaction was investigated with the reduction peak current measured. bining the specific properties such as the patibility and big surface area of Fe(3)O(4) microspheres, the excellent electron transfer ability of GR, the good film-forming ability of CTS and the high conductivity of CILE, the synergistic effects of posite increased the amounts of ssDNA adsorbed on the electrode surface and then resulted in the greatly increase of the electrochemical responses. Under the optimal conditions differential pulse voltammetric responses of MB were proportional to the specific ssDNA sequences concentration in the range from 1.0×10(-12) to 1.0×10(-6)mol/L with the detection limit as 3.59×10(-13)mol/L (3σ). This DNA biosensor showed good stability and discrimination ability to one-base and three-base mismatched ssDNA sequences. The polymerase chain reaction (PCR) product of soybean Lectin gene sequence was detected by the proposed method with satisfactory result, suggesting that the CTS/Fe(3)O(4)-GR/CILE was a suitable sensing platform for the sensitive detection of specific gene sequence. |
22099657 | Simultaneous injection effective mixing analysis system for the determination of direct bilirubin in urinary samples. | A novel simultaneous injection effective mixing analysis system (SIEMA) for determination of direct bilirubin in urine sample was developed. Bilirubin reacts with diazotized sulfanilic acid in the presence of n-octyl-β-d-thioglucoside (OTG) as a solubilizing agent to form OTG-azobilirubin. The flow and chemical variables were investigated. A linear calibration graph for direct bilirubin was obtained over the range of 0-1.0 mg L(-1) (r(2)=0.994) with the limit of detection (3σ) of 4.7 μg L(-1), and the relative standard deviation (RSD) being 1.9% (n=11, 0.5 mg L(-1) of direct bilirubin). The results in healthy adult urine obtained by the proposed approach were found in good agreement with those obtained by the batch-wise diazo method. |
22099658 | SPME-GC determination of methanol as a hydrate inhibitor in crude oil. | This work focused on the quantitation of methanol as a hydrate inhibitor in the crude oil. The novelty is microextraction of a pound from plex non-polar matrix and selection of proper fiber with maximum selectivity, loading percent, and lifetime. This approach not only does not require specific instrumentation, such as multiple columns, and selective detectors, but also has eliminated the use of organic solvent and avoids the insertion of water inside the GC columns. The objective is optimization of extraction conditions, GC adjustments and data processing. Experiments were conducted on the real sample of Iranian offshore crude oil by a carboxen/PDMS fiber via a GC equipped with a cross-linked polyethylene glycol column and FID. The results revealed that this fiber adsorbed the alcohols among other light pounds of crude oil. Moreover, the interference effects of ethanol were solved by proper selection of thermal program. The LOD, LOQ and linear range of this approach were determined to be 3.9, 12.9 and 14-229 mg L(-1) for methanol, respectively. Moreover, the sensitivity was 30 area-counts per mg L(-1). Using the standard calibration and the standard addition methods, the relative errors of 1.6-7.2 and 5.3-14.0% were determined, respectively. |
22099659 | Novel CeO₂-based screen-printed potentiometric electrodes for pH monitoring. | Nuclear waste repositories are being installed in deep excavated rock formations in some places in Europe to isolate and store radioactive waste. In France, the Callovo-Oxfordian formation (COx) is a possible candidate for nuclear waste storage. This work investigates the applicability of CeO(2)-based oxides (CeO(2), Ce(0.8)Sm(0.2)O(2) and Ce(0.8)Zr(0.2)O(2)) for monitoring the pH of the COx pore water (T=25°C). The study is limited to the pH range between 5.5 and 13.2, which includes the pH values that have been encountered or are anticipated in the COx formation during its evolution as radioactive waste repository due mainly to alkalinisation, an increase in salinity, and a decrease in redox potential. Screen-printing was done to assemble electrodes and rapidly generate data sets. The electrochemical behavior of CeO(2)-based screen-printed electrodes (CeO(2)-based SPEs) was determined by cyclic voltammetry and electrochemical impedance spectroscopy. The use of the electrodes for pH sensing was then evaluated by potentiometric measurements. The feasibility of measuring pH with CeO(2)-based SPEs was first tested in NH(4)Cl/NH(3) buffer solutions, leading to electrode calibration over the widest range of pH, from around neutral to basic pH. Experiments were then conducted in NaHCO(3)/Na(2)CO(3) buffer samples similar to conditions prevailing in the COx formation. Ce(0.8)Zr(0.2)O(2) SPEs exhibit a near-Nernstian behavior (sensitivity -(51±2)mV/pH) in the pH range of 5.5-13.2 at 25°C. Electrode response was slightly affected by the direction of the pH change. Electrode reliability was clearly demonstrated for pH monitoring. Probes based on the ponents, but more durably designed, could be considered for pH measurements in radioactive waste repositories. |
22099660 | Discrimination and sensory description of beers through data fusion. | Beer samples of the same brand mercialized as a same product, but brewed in four different factories were analyzed with three techniques, an MS e-nose, a mid-IR optical-tongue and a UV-visible, to see if the factories show differences and to find out if the differences found could be attributed to different sensory properties. The data from the three instruments were fused to improve the ability of classification with respect to the individual use of the techniques. Two levels of data fusion were studied: low and mid level fusion, and the classification was performed by linear discriminant analysis (LDA). Mid-level fusion provided better classification results (above 95% correct classification) than those of low-level fusion and also than those obtained when using the individual techniques. Moreover, by means of the score and loading plots obtained by Fisher-LDA, it was possible to interpret the chemical information provided by the three techniques, and we were able to relate the variables associated to each sensor to the pounds responsible of the sensory perception. |
22099661 | Application of low-temperature CP-Sil 88 column for the isomeric analysis of toxic 2,378-substituted PCDD/Fs in incinerator flyash and sewage sludge using a triple quadrupole GC-MS/MS. | The seventeen 2378-substituted polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs) congeners have been separated and analyzed in sewage sludge and incinerator flyash samples using a CP-Sil 88 column (50 m × 0.25 mm I.D., 0.25 μm film thickness) operating at a maximum oven temperature of 240°C. The column was used on a Varian 450-GC with a Varian 320-MS Triple Quadrupole. Calibration standards were used to determine the transition chemistries of the 2378-substituted PCDD/F congeners in the gas chromatography/mass spectrometry (GC-MS/MS) system. The five-point calibration curve for each of the congeners showed very good linearity with R(2) values greater than 0.999. The recovery of pounds ranged from 50% to 120%. Analytical results from a reference flyash (BCR-490) and a reference sewage sludge pared very well with the certified values, giving percentage deviations in I-TEQ (international toxic equivalents) of 4.93% and 0.53%, respectively. Results from 'real' flyash samples underscored the level of progress made in the abatement of dioxin emissions from incinerators; the old incinerator flyash contained much higher PCDD/F concentrations than the modern one. In addition, the concentrations profiles of PCDD/Fs in the 'real' sewage sludge from two UK wastewater treatment plants (WWTPs) showed that one contained a total PCDD/Fs content of 314 ng I-TEQ kg(-1), while the other gave a total of 53 ng I-TEQ kg(-1). Over an 18-month period of operation, no significant loss of analytical performance was observed from the low-temperature column. |
22099662 | Development of a screening method for the analysis of organic pollutants in water using dual stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry. | The development of a method for screening of pounds with a wide range of physico-chemical properties in water, based on dual stir bar sorptive extraction coupled with thermal desorption and gas chromatography-mass spectrometry (dual SBSE-TD-GC-MS) is described. The investigated water sample is divided into two aliquots and extracted with stir bar sorptive extraction at two different conditions: using addition of methanol or sodium chloride, respectively. Following extraction, the two stir bars are inserted into the same glass thermal desorption liner and are simultaneously desorbed and analysed by GC-MS. The method optimisation was performed using 45 environmentally harmful substances with different volatilities (boiling point from 193 to 495°C), polarity (logK(ow) from 2.17 to 8.54) and acido-basic properties. The majority of pounds was selected from the EU list of priority substances in the field of water policy and from the US EPA method 625, respectively. Optimisation was performed for extraction parameters (sample volume, extraction time, stirring rate, addition of modifiers) as well as for the thermal desorption conditions (desorption flow, desorption time, cryofocusing temperature). Performance characteristics (recovery, repeatability, carryover, linearity, limits of detection and quantification) were determined for the optimised method. An example of analysis of a contaminated groundwater sample is presented. |
22099663 | Phosphate determination in seawater: toward an autonomous electrochemical method. | Initial steps to create an autonomous in situ electrochemical sensor for orthophosphate determination in seawater are presented. First, the optimal conditions to form the plex in artificial seawater medium were determined by addition of sulphuric acid and sodium molybdate to the solution containing orthophosphate. Secondly, the anodic oxidation of molybdenum to form molybdate ions and protons was used to create the plex without addition of any liquid reagents. The plex is detectable by amperometry with an average precision of 2.2% for the concentration range found in the open ocean and the detection limit is 0.12 μM. Three solutions are proposed to address the silicate interferences issue and one of these methods is used for the natural samples collected in the coastal waters offshore Peru during the Pelagico 1011-12-BIC OLAYA cruise in November-December 2010. Results showed a good precision with an average of 2.5% and a reasonable deviation of the amperometric analysis pared with colorimetric measurements (4.9%). |
22099666 | Theil-Sen nonparametric regression technique on univariate calibration, inverse regression and detection limits. | This paper reports bined use of the nonparametric Theil-Sen (TS) regression technique and of the statistics of Lancaster-Quade (LQ) concerning the linear regression parameters to solve typical analytical problems, like parison, calculation of the uncertainty in the inverse regression, determination of the detection limit. The results of this new approach pared to those obtained with appropriate reference methods, using simulated and real data sets. The nonparametric Theil-Sen regression technique appears a new robust tool for the problems considered because it is free from restrictive statistical constraints, avoids searching for the error nature on x and y, which may require long analysis times, and it is easy to use. The only drawback is that the intrinsic nature of the method may lead to a possible enlargement of the uncertainty interval of the discriminated concentration and to the determination of larger detection limits than those obtainable with monly used, less robust, regression techniques. |
22099665 | Microdiffusion-based UV-LED spectrometric setup for determining low levels of ethanol in fruit juice. | A novel setup is described in which bined the separation of a volatile substance from a sample with plex matrix on the basis of a microdiffusion process with a kinetic on-line spectrometric monitoring of the reaction in the receptive medium at 365 nm. The fruit juice was selected as a model for testing the performance of the setup in real-life applications. The ethanol content in fruit juice can be considered as an indicator of the fruit-juice quality and should not exceed the regulatory limiting values. After optimising the microdiffusion process, blackcurrant, orange and two varieties of apple juice were analysed. The sample analysis lasted 15 min at 35°C. The ethanol concentrations were found to be between 0.9 and 4.0 mmol/L, and parable to the results obtained using the SIST:ISO 2448:1998 standard method, which is time consuming, labour intensive and requires high sample volumes. The setup can easily be adapted for determining other volatile substances in low concentrations plicated samples of different types by introducing different chemistry and replacing the light source if the light of a different wavelength is required. The measuring characteristics of the setup were critically assessed, the main sources of uncertainty recognised and the possibilities for further improvements of the setup and the procedure considered. |
22099664 | One-step coating of silica capillaries for selective protein retention by Cu(II)-IDA IMAC. | A simple protocol to obtain Cu(II)-IDA (iminodiacetic acid)-modified capillaries was developed for immobilized metal ion affinity chromatography (IMAC). It consisted in the synthesis of IDA-silane used for a one-step coating of fused silica capillaries. The approach prevented the hydrolysis of silica potentially induced by two step coatings (γ-GPTMS, then IDA) employed in the conventional method of bonding iminodiacetic acid. The IDA content was quantified using a model relating the electroosmotic flow generated in IDA-modified capillaries to the charges induced by IDA species. The retention behavior of holotransferrin and bovine serum albumin on these IMAC columns was then investigated. Holotransferrin revealed a high affinity for Cu(II)-supports through a specific interaction with Cu(II) ions whereas albumin did not show any retention. The use of such columns for sample pretreatment before an HPLC analysis was proved to be successful. |
22099668 | Chemometric tools to evaluate the spatial distribution of trace metals in surface sediments of two Spanish rías. | A suite of relevant trace metals (Hg, Pb, Cd, Cu, Zn and Ni) was measured in surface sediment samples to assess the environmental situation of the largest two Atlantic Spanish 'rías' (a form of estuaries, ría of Pontevedra, ROP, and ría of Vigo, ROV). The level of contamination originated by these metals was assessed against international guidelines, the threshold effect, ERL, and the midrange effect, ERM. Six unsupervised and supervised multivariate chemometric techniques were applied to model each pare them and select those metals that characterize the samples. This is first time that such a study is performed for these two important seafood-producing areas. Maximum concentrations at ROP occurred in the vicinities of an inner island, where Cu, Zn, Ni and Pb presented concentrations over the ERL and Hg over the ERM. Highest concentrations of metals in ROV were observed in the proximities of Vigo shipyards and port, except for Pb, with peak values in San Simon Bay. ERL limits were exceeded in the inner part of this ría for Cu, Zn and Hg and in a wider area for Pb and Ni. Levels for Pb went beyond the ERM boundary in the axial part of San Simon Bay. In general, the distribution of the metals was more homogeneous in ría of Pontevedra than in ría of Vigo (where three morphological zones were characterized). Both rías could be differentiated using only two metals: Ni and Hg, as deduced from the multivariate techniques. |
22099667 | Amperometric biosensors based on deposition of gold and platinum nanoparticles on polyvinylferrocene modified electrode for xanthine detection. | In this study, new xanthine biosensors, XO/Au/PVF/Pt and XO/Pt/PVF/Pt, based on electroless deposition of gold(Au) and platinum(Pt) nanoparticles on polyvinylferrocene(PVF) coated Pt electrode for detection of xanthine were presented. The amperometric responses of the enzyme electrodes were measured at the constant potential, which was due to the electrooxidation of enzymatically produced H(2)O(2). Compared with XO/PVF/Pt electrode, XO/Au/PVF/Pt and XO/Pt/PVF/Pt exhibited excellent electrocatalytic activity towards the oxidation of the analyte. Effect of Au and Pt nanoparticles was investigated by monitoring the response currents at the different deposition times and the different concentrations of KAuCl(4) and PtBr(2). Under the optimal conditions, the calibration curves of XO/Au/PVF/Pt and XO/Pt/PVF/Pt were obtained over the range of 2.5 × 10(-3) to 0.56 mM and 2.0 × 10(-3) to 0.66 mM, respectively. The detection limits were 7.5 × 10(-4)mM for XO/Au/PVF/Pt and 6.0 × 10(-4)mM for XO/Pt/PVF/Pt. The effects of interferents, the operational and the storage stabilities of the biosensors and the applicabilities of the proposed biosensors to the drug samples analysis were also evaluated. |
22099669 | A copper interdigitated electrode and chemometrical tools used for the discrimination of the adulteration of ethanol fuel with water. | A new approach for the discrimination of the adulteration process of ethanol fuel with water is reported using a copper interdigitated electrode and chemometrical tools. The sensor was constructed using copper sheets with non-chemical modification of the electrode surface. The discrimination process was performed using capacitance values recorded at different frequencies (1,000 Hz to 0.1 MHz) as the input data for non-supervised pattern recognition methods (PCA: ponent analysis and HCA: hierarchical cluster analysis). The relative standard deviation for the capacitance signals obtained from ten independent interdigitated sensors was below 5.0%. The ability of the device to differentiate non-adulterated ethanol samples from those adulterated with water was demonstrated. In all analysed cases, there was good separation between the different samples in the score plots and the dendrograms obtained from PCA and hierarchical cluster analyses, respectively. Furthermore, the water content was quantified using a PCA approach. The results were consistent with those obtained using the Karl-Fischer method at a 95% confidence level, as measured using Student's t-test. |
22099670 | A specific probe for two-photon fluorescence lysosomal imaging. | Lysosomes are vital organelles in physiological processes, as they receive and degrade macromolecules from the secretory and endocytic procedures. Evidences have shown that lysosomes were related to oncogenic activation and cancer progression, so lysosomes targeting and imaging probes make them convenient to be observed. In this study, a lysosome specific probe W-7 was designed and synthesized via convenient one-pot reaction and Heck reaction. This probe was derived from Tröger's base with a dimethylaminomethyl end group. The optical properties of pound were measured. W-7 also showed two-photon absorption (TPA) effect by using laser excitation at the wavelength of infrared light. In vivo experiment, W-7 showed high specificity and selectivity for lysosomes in living cells (HeLa cells, MRC-5 cells and NRK pared with LT Red, GT Red and MT Red (R=0.96). Two-photon fluorescence images of HeLa cells stained by W-7 were obtained. And high resolution 3D reconstruction of lysosomes in one HeLa cell was provided by using two-photon confocal microscopy. The anantioseparation of racemic W-7 was carried out by chiral-HPLC, and the two enantiomers showed no significant difference in lysosomes imaging. |
22099671 | Forced degradation study to develop and validate stability-indicating RP-LC method for the determination of ciclesonide in bulk drug and metered dose inhalers. | A simple, selective and precise stability-indicating reversed-phase liquid chromatographic method was developed and validated for the determination of ciclesonide. Ciclesonide was subjected to acid and alkali hydrolysis, oxidation, thermal and photo-degradation. The degradation products were well separated from the pure drug. The method was based on isocratic elution of ciclesonide and its degradation products on reversed phase C18 column (250 mm × 4.6 mm, 10 μm) - Phenomenex using a mobile phase consisting of ethanol-water (70:30, v/v) at a flow rate of 1 mL min(-1). Quantitation was achieved with UV detection at 242 nm. Linearity, accuracy and precision were found to be acceptable over the concentration range of 5-200 μg mL(-1). Desisobutyryl-ciclesonide was prepared by selective alkaline hydrolysis of the ester and proved to be the main degradation product. The proposed method was successfully applied to the determination of ciclesonide in bulk and in its pharmaceutical preparation. |
22099672 | Cobalt(II) selective membrane electrode based on palladium(II) dichloro acetylthiophene fenchone azine. | A new cobalt(II) ion selective electrode based on palladium(II) dichloro acetylthiophene fenchone azine(I) has been developed. The best position is found to be 10:60:10:21.1 (I)/PVC/NaTPB/DOP (w/w). The electrode exhibits a Nerstian response in the range of 1.0 × 10(-1)-1.0 × 10(-6)M with a detection limit and slope of 8.0 × 10(-7)M and 29.6 ± 0.2 mV per decade respectively. The response time is within the range of 20-25s and can be used for a period of up to 4 months. The electrode developed reveals good selectivity for cobalt(II) and could be used in pH range of 3-7. The electrode has been successfully used in the determination of cobalt(II) in water samples. |
22099673 | Indirect determination of sulfite using a polyphenol oxidase biosensor based on a glassy carbon electrode modified with multi-walled carbon nanotubes and gold nanoparticles within a poly(allylamine hydrochloride) film. | The modification of a glassy carbon electrode with multi-walled carbon nanotubes and gold nanoparticles within a poly(allylamine hydrochloride) film for the development of a biosensor is proposed. This approach provides an efficient method used to immobilize polyphenol oxidase (PPO) obtained from the crude extract of sweet potato (Ipomoea batatas (L.) Lam.). The principle of the analytical method is based on the inhibitory effect of sulfite on the activity of PPO, in the reduction reaction of o-quinone to catechol and/or the reaction of o-quinone with sulfite. Under the optimum experimental conditions using the differential pulse voltammetry technique, the analytical curve obtained was linear in the concentration of sulfite in the range from 0.5 to 22 μmol L(-1) with a detection limit of 0.4 μmol L(-1). The biosensor was applied for the determination of sulfite in white and red wine samples with results in close agreement with those results obtained using a reference iodometric method (at a 95% confidence level). |
22099674 | An amperometric hydrogen peroxide chemical sensor based on graphene-Fe₃O₄ multilayer films modified ITO electrode. | In this article, poly(diallydimethylammonium chloride) (PDDA) functionalized graphene-Fe(3)O(4) (PDDA-G/Fe(3)O(4))(n) multilayer films were fabricated with layer-by-layer assembly of negatively charged Fe(3)O(4) nanoparticles (Fe(3)O(4) NPs) and positively charged PDDA-G through the electrostatic interaction to construct a H(2)O(2) chemical sensor. The multilayer films were characterized with UV-vis spectroscopy, atomic force microscopy and cyclic voltammetry. The participation of PDDA-G improved the catalytic ability of Fe(3)O(4) NPs due to its high surface area and excellent electric conductivity. Based on this, the obtained H(2)O(2) chemical sensor exhibited prominent electrocatalytic activity for the detection of H(2)O(2) with a wide linear range from 20 μM to 6.25 mM, a rapid response upon the addition of H(2)O(2) and a low detection limit of 2.5 μM with the signal to noise ratio of three. Furthermore, the fabricated nonenzymatic H(2)O(2) chemical sensor exhibited excellent stability and reproducibility. |
22099675 | Rapid determination of pyridine derivatives by dispersive liquid-liquid microextraction coupled with gas chromatography/gas sensor based on nanostructured conducting polypyrrole. | Polypyrrole (PPy) gas sensor has been prepared by polymerization of pyrrole on surfaces mercial polymer fibers in the presence of an oxidizing agent. The sensing behavior of PPy gas sensor was investigated in the presence of pyridine derivatives. The resistive responses of the PPy gas sensor to pyridine derivatives were in the order of quinoline>pyridine>4-methyl pyridine and 2-methyl pyridine. The PPy gas sensor was used as gas chromatography (GC) detector and exhibited linear responses to pyridine derivatives in the ranges 40-4,000 ng. Dispersive liquid-liquid microextraction bined with GC/PPy gas sensor has been developed for simultaneous determination of pyridine derivatives and quinoline. The purposed method was used for determination of pyridine derivatives from cigarette smoke. The GC runs pleted in 4 min. The reproducibility of this method is suitable and good standard deviations were obtained. RSD value is less than 10% for all analytes. |
22099676 | Hydride generation in-atomizer collection atomic absorption spectrometry for the determination of antimony in acetic acid leachates from pewter cups. | Antimony is one of the constituents of pewter, an posed of a minimum of 90% tin with the balance being made up with copper, antimony and perhaps some bismuth. A method has been developed to determine Sb in acetic acid leachates from pewter cups. The employed instrumentation, an atomic absorption spectrometer, equipped with a quartz trap-and-atomizer device, is simple and relatively inexpensive with low running costs. Interferences due to the presence of tin and ways to control them were investigated in detail. The applied approach made possible to e potentially serious interference of Sn leached from the cup material (which was shown to take place in the atomizer), by bination of (i) high concentration of HCl, which decreases the efficiency of stannane generation and (ii) in-atomizer collection. The resulting Sn tolerance limit was between 10 and 20 mg L(-1). The advantages of the in-atomizer collection are a lower tin interference in the atomizer, and a much better limit of detection (LOD), which makes possible reducing the atomization interference further by working with more diluted sample solutions. Besides the Sn interference, an interference of an unknown pound transported to the atomizer together with stibine was identified in the measured sample solutions. This interference could be controlled using the analyte addition technique. The applicability of the method was tested on solutions containing a wide range of interferents leached from the pewter cups, obtained at leaching times between 1 and 24h. The LOD in the sample solutions was found to be 0.03 μg L(-1) Sb. |
22099677 | Synthesized mercaptopropyl nanoporous resins in DGT probes for determining dissolved mercury concentrations. | 3-Mercaptopropyl functionalized SBA-15 (SH-SBA) and 3-mercaptopropyl functionalized ethenylene bridged periodic mesoporous organosilica (SH-PMO) were included in a Diffusive Gradients in Thin film (DGT) probe pared to mercially available resins also containing thiol functional groups, such as Sumichelate Q10R (SQR) and 3-mercaptopropyl functionalized silica gel (SH-KG), and also to the Chelex-100 resin for the determination of labile Hg concentrations. An agarose gel was used as the diffusive gel because the classic polyacrylamide gel shows more than 20% of Hg adsorption. According to our results, the Chelex-100 resin presents a much lower affinity for Hg than the thiol based resins. The non-linear accumulation profile of mercury with time for the Chelex-100 resin makes it in fact impossible to use Fick's law for estimating the diffusion coefficient of Hg. The 4 other resins all show a linear accumulation profile of Hg with time. Although the highest accumulation rate is observed for SH-PMO followed by SQR, SH-SBA and SH-KG, these values do not differ very much. |
22099678 | Comparison of two derivatization reagents for the simultaneous determination of organolead and organomanganese compounds using solid-phase microextraction followed by gas chromatography with atomic emission detection. | Two procedures for the simultaneous determination of organolead (tetraethyllead, triethyllead and trimethyllead) and pounds (cyclopentadienyl manganese tricarbonyl (CMT) and methylcyclopentadienyl manganese tricarbonyl (MMT)) are studied. Both procedures involve sample preconcentration by solid-phase microextraction and capillary gas chromatography coupled to atomic emission detection, the main difference being the derivatizing agent used for the ionic alkylated lead species: sodium tetrapropylborate (NaBPr(4)) and sodium tetraphenylborate (NaBPh(4)). The parameters affecting the derivatization and preconcentration steps, chromatographic separation as well as detection of pounds were optimized. Higher sensitivity was attained for pounds with the method involving propylation derivatization. In this case, detection limits ranged between 0.04 and 0.1 ng L(-1), depending on pound. Detection limits of between 0.1 and 24.5 ng L(-1) were obtained, when using phenylation derivatization. A low CMT concentration was found in one of the seawater samples analyzed. |
22099679 | Dual fluorescence and electrochemical detection of the organophosphorus pesticides--ethion, malathion and fenthion. | Organophosphorus (OP) based pesticides are known powerful inhibitors of cholinesterases, thus the toxicity of this class pounds causes serious environmental and human health concerns. We report that benzodipyrido[3,2-a:2',3'-c]phenazine (BDPPZ) and 3,6-dimethylbenzodipyrido-[3,2-a:2',3'-c]phenazine (DM-BDPPZ) provide independent fluorescent and electrochemical signal transductions in the presence of the organophosphorus (OP) pesticides; fenthion, malathion and ethion. The presence of the methyl groups at the 3 and 6 positions in DM-BDPPZ was found to significantly influence the sensor performance. The difference in the fluorescence and electrochemical signals produced by the interaction of the pound with each of the OP pesticides provides a means for differentiating between the three pesticides. Detection limits of 10(-8)M, 10(-9) and 10(-12)M were obtained for fenthion, malathion and ethion, respectively. Due to the high sensitivity and ability to minimize false positives these new sensors will be useful for potential integration for future environmental use. |
22099680 | Analytical method development using functionalized polysulfone membranes for the determination of chlorinated hydrocarbons in water. | In this study, functionalized polysulfone membrane has been utilized as a sorbent for the extraction of chlorinated hydrocarbons (CHCs) in water samples. Two different functionalized polysulfones (i) phosphonic acid functionalized polysulfone (PPSU-A) with different forms (cross-linked and non cross-linked) membranes and (ii) phosphonic ester functionalized polysulfone (PPSU-E) with different forms (cross-linked and non cross-linked) were evaluated for the extraction of CHCs in water. A 10 ml of spiked water sample was extracted with 50mg piece of the functionalized membrane. After extraction, the membrane was desorbed by organic solvent and the extract was analyzed by gas chromatography-mass spectrometry. Eight CHCs, 1,3,5-trichlorobenzene (1,3,5-TCB), 1,2,3-trichlorobenzene (1,2,3-TCB), 1,1,2,3,4,4-hexachloro-1,3-butadiene (HCBD), 1,2,4-trichloro-3-methylbenzene (TCMB), 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB), pentachlorobenzene (PeCB) and hexachlorobenzene (HCB) were used as pounds. Experimental parameters such as extraction time, desorption time, types of polymer membrane as well the nature of desorption solvent were optimized. Using optimum extraction conditions calibration curves were linear with coefficients of determination between 0.9954 and 0.9999 over wide range of concentrations (0.05-100 μgl(-1)). The method detection limits (at a signal-to-noise ratio of 3) were in the range of 0.4-3.9 ng l(-1). The proposed method was evaluated for the determination of CHCs in drinking water samples. |
22099681 | Thermo-optical determination of vapor pressures of TNT and RDX nanofilms. | Accurate thermodynamic parameters of thin films of explosives are important for understanding their behavior in the nanometer scale as well as in standoff detection. Using UV-absorbance spectroscopy technique, accurate thermodynamic parameters such as activation energies of sublimation, sublimation rates, and vapor pressures of the explosives cyclotrimethylenetrinitramine (RDX) and 2,4,6-trinitrotoluene (TNT) were determined. The values of these parameters are in excellent agreement with those reported using traditional experiments based on gravimetry. In terms of the Clapeyron equation, the dependence of RDX and TNT vapor pressures on temperature can be described by the relations LnP (Pa)=39.6-15459/T (K) and LnP (Pa)=34.9-12058/T (K), respectively. Heats of sublimation of RDX and TNT were also determined to be 128kJ/mol and 100.2kJ/mol, respectively. |
22099682 | Selectivity coefficients of ion-selective magnesium electrodes used for simultaneous determination of magnesium and calcium ions. | Membrane ion-selective magnesium electrodes monly used to determine ionized magnesium concentration in blood serum and intracellular fluid by potentiometric clinical analyzers. The selectivity of these electrodes against calcium ion is typically insufficient to avoid calcium interference in blood serum analysis. For this reason the selectivity coefficient for calcium ion has to be studied to make possible any mathematical corrections for calcium ion influence. Existing methods relate to the thermodynamic concept of ISE response which suggest a single constant value of the selectivity coefficient and slope that are stable over the concentration ranges of calcium and magnesium ions in the samples. Unfortunately, this rarely happens, and we rather observe dependences on solution and position, readout time, matrices (anticoagulant, vial coats) that justify usage of apparent selectivities and slopes. To get the practical insight into the response of magnesium ion-selective electrodes a novel method for estimating the selectivity coefficients and the slope of the electrode characteristics is proposed. This method is an effective starting point for selecting electrodes and designing transient signal software in a potentiometric clinical analyzer. The method allows obtaining the ionized magnesium concentration in blood serum with minimal possible error by addressing the assessed targets, i.e. apparent selectivity and slope. The method is based puter simulation and on the Nicolsky-Eisenman equation. Usually only a few iterations are needed to obtain stable congruent results. The method presented is particularly useful in conditions where is not possible to obtain calibration curve, which is typical for clinical analyzer where at most three point calibration is performed. |
22099683 | Magnetic beads-based electrochemical immunosensor for detection of pseudorabies virus antibody in swine serum. | A novel magnetic electrochemical immunosensor has been developed for the detection of pseudorabies virus antibody in swine serum. The magnetic glass carbon electrode was fabricated to manipulate magnetic beads for the direct sensing applications. Magnetic beads were employed as the platforms for the immobilization and immunoreaction process, and gold nanoparticles were chosen as electroactive labels for the electrochemical detection. The parameters concerning the assay strategy were carefully investigated. Under the optimal conditions, the linear response range of pseudorabies virus antibody dilution ratio (standard positive serum) was 1:250 to 1:1000 with a detection limit of 1:1000. Finally, this developed immunoassay method was successfully applied in the detection of pseudorabies virus antibody in swine serum, and had a good diagnostic accordance parison with ELISA. |
22099684 | Expanding the linear dynamic range for multiple reaction monitoring in quantitative liquid chromatography-tandem mass spectrometry utilizing natural isotopologue transitions. | We describe a method for expanding the linear dynamic range for multiple reaction monitoring (MRM) in quantitative liquid chromatography/tandem mass spectrometry (LC-MS/MS) using additional transitions for isotopologues. In addition to the regular transition for the highest possible sensitivity, a transition corresponding to the less abundant isotopologue ions was utilized. This decreases saturation at the ion detector; the sensitivity reduction increases the upper dynamic limit. We demonstrated this for a rat plasma assay for a candidate pound; the linear dynamic range increased by an order of magnitude from 3 to 6,000 ng/mL with the regular MRM alone to 3-60,000 ng/mL using additionally the isotopologue transition. |
22099686 | Metabolic syndrome in obese adolescents is associated with risk for nephrolithiasis. | To examine the relationship between urinary pH and metabolic syndrome risk factors along with insulin resistance in obese adolescents, and to evaluate the relationship between other urinary stone-forming and -inhibiting markers and metabolic syndrome. |
22099687 | 2009 influenza A in infants hospitalized at younger than 6 months. | To describe the clinical characteristics and es of infants hospitalized at <6 months of age with 2009 influenza A infection. |
22099689 | Co nanoparticle hybridization with single-crystalline Bi nanowires. | Crystalline Co nanoparticles were hybridized with single-crystalline Bi nanowires simply by annealing Co-coated Bi nanowires at elevated temperatures. An initially near-amorphous Co film of 2-7 nm in thickness began to disrupt its morphology and to be locally transformed into crystallites in the early stage of annealing. The Co film became discontinuous after prolonged annealing, finally leading to isolated, crystalline Co nanoparticles of 8-27 nm in size. This process spontaneously proceeds to reduce the high surface tension and total energy of Co film. The annealing time required for Co nanoparticle formation decreased as annealing temperature increased, reflecting that this transformation occurs by the diffusional flow of Co atoms. The Co nanoparticle formation process was explained by a hole agglomeration and growth mechanism, which is similar to the model suggested by Brandon and Bradshaw, followed by the nanoparticle refinement. |
22099691 | Genetic and phenotypic consequences of introgression between humans and Neanderthals. | Strong evidence for introgression of Neanderthal genes into parts of the modern human gene pool has recently emerged. The evidence indicates that some populations of modern humans have received infusions of genes from two different groups of Neanderthals. One of these Neanderthal groups lived in the Middle East and Central Europe and the other group (the Denisovans) is known to have lived in Central Asia and was probably more widespread. This review examines two questions. First, how were these introgressions detected and what does the genetic evidence tell us about their nature and extent? We will see that an unknown but possibly large fraction of the entire Neanderthal plement may have survived in modern humans. Even though each modern European and Asian carries only a few percent of genes that can be traced back to Neanderthals, different individuals carry different subgroups of these introgressed genes. Second, what is the likelihood that this Neanderthal genetic legacy has had phenotypic effects on modern humans? We examine evidence for and against the possibility that some of the surviving fragments of Neanderthal genomes have been preserved by natural selection, and we explore the ways in which more evidence bearing on this question will e available in the future. |
22099692 | Genomic approaches to understanding Hox gene function. | For many years, biologists have sought to understand how the homeodomain-containing transcriptional regulators encoded by Hox genes are able to control the development of animal morphology. Almost a century of genetics and several decades of molecular biology have defined the conserved organization of homeotic gene clusters in animals and the basic molecular properties of Hox transcription factors. In contrast to these successes, we remain relatively ignorant of how Hox proteins find their target genes in the genome or what sets of genes a Hox protein regulates to direct morphogenesis. The recent deployment of genomic methods, such as whole transcriptome mRNA expression profiling and genome-wide analysis of protein-DNA interactions, begins to shed light on these issues. Results from such studies, principally in the fruit fly, indicate that Hox proteins control the expression of hundreds, if not thousands, of genes throughout the gene regulatory network and that, in many cases, the effects on the expression of individual genes may be quite subtle. Hox proteins regulate both high-level effectors, including other transcription factors and signaling molecules, as well as the cytodifferentiation genes or Realizators at the bottom of regulatory hierarchies. Insights emerging from mapping Hox binding sites in the genome begin to suggest that Hox binding may be strongly influenced by chromatin accessibility rather than binding site affinity. If this is the case, it indicates we need to refocus our efforts at understanding Hox function toward the dynamics of gene regulatory networks and chromatin epigenetics. |
22099690 | Sensory functions for degenerin/epithelial sodium channels (DEG/ENaC). | All animals use a sophisticated array of receptor proteins to sense their external and internal environments. Major advances have been made in recent years in understanding the molecular and genetic bases for sensory transduction in diverse modalities, indicating that both metabotropic and ionotropic pathways are important in sensory functions. Here, I review the historical background and recent advances in understanding the roles of a relatively newly discovered family of receptors, the degenerin/epithelial sodium channels (DEG/ENaC). These animal-specific cation channels show a remarkable sequence and functional diversity in different species and seem to exert their functions in diverse sensory modalities. Functions for DEG/ENaC channels have been implicated in mechanosensation as well as chemosensory transduction pathways. In spite of overall sequence diversity, all family members share a unique protein topology that includes just two transmembrane domains and an unusually large and highly structured extracellular domain, that seem to be essential for both their mechanical and chemical sensory functions. This review will discuss many of the recent discoveries and controversies associated with sensory function of DEG/ENaC channels in both vertebrate and invertebrate model systems, covering the role of family members in taste, mechanosensation, and pain. |
22099693 | GATA transcription factors in the developing reproductive system. | Previous work has firmly established the role for both GATA4 and FOG2 in the initial mitment to sexual fate, but their (joint or individual) function in subsequent steps remained unknown. Hence, gonad-specific deletions of these genes in mice were required to reveal their roles in sexual development and gene regulation. The development of tissue-specific Cre lines allowed for substantial advances in the understanding of the function of GATA proteins in sex determination, gonadal differentiation and reproductive development in mice. Here we summarize the recent work that examined the requirement of GATA4 and FOG2 proteins at several critical stages in testis and ovarian differentiation. We also discuss the molecular mechanisms involved in this regulation through the control of Dmrt1 gene expression in the testis and the canonical Wnt/ß-catenin pathway in the ovary. |
22099694 | [A rare cause of arterial hypertension in children: Takayasu arteritis]. | Takayasu arteritis, a nonspecific inflammatory arteritis, is particularly rare in children. We report the case of a 6-year-old girl presenting with severe arterial hypertension in the upper segment associated with an inflammatory syndrome. Investigations showed coarctation of the abdominal aorta at different levels, due to Takayasu arteritis. The patient was treated with percutaneous dilatation and stent implantation as well as prolonged anti-inflammatory therapy. Arterial hypertension in children needs to be investigated until its cause, which may be rare, such as Takaysu arteritis, is determined. |
22099696 | [PELVIS or LUMBAR syndrome: the same entity. Two case reports]. | The association of a pelvic hemangioma and malformations in the pelvic region are described as SACRAL or PELVIS syndrome. More recently, the acronym of LUMBAR syndrome has been used to describe the association of lower-body hemangioma and other cutaneous defects, urogenital anomalies, ulceration, myelopathy, bony deformities, anorectal malformations, arterial anomalies, and renal anomalies. We report herein 2 representative cases. |
22099698 | Planer orientation of the bilateral semicircular canals in dizzy patients. | Recent development of 3-dimensional analysis of eye movement enabled to detect the eye rotation axis, which is used to determine the responsible semicircular canal(s) in dizzy patients. Therefore, the knowledge of anatomical orientation of bilateral semicircular canals is essential, as all 6 canals influence the eye movements. |
22099699 | Endoscopic sinus surgery: a safe procedure among the less experienced surgeons? | To determine the incidence plications in endoscopic sinus surgery (ESS), in a surgical centre with 20 years of experience, and whether or not the surgeon's experience can be a predisposing factor for them to happen. |
22099700 | Retinal vessel segmentation using a multi-scale medialness function. | Recently, automated segmentation of retinal vessels in optic fundus images has been an important focus of much research. In this paper, we propose a multi-scale method to segment retinal vessels based on a weighted two-dimensional (2D) medialness function. The results of the medialness function are first multiplied by the eigenvalues of the Hessian matrix. Next, centerlines of vessels are extracted using noise reduction and reconnection procedures. Finally, vessel radii are estimated and retinal vessels are segmented. The proposed method is evaluated pared with several recent methods using images from the DRIVE and STARE databases. |
22099701 | Structural alphabet motif discovery and a structural motif database. | This study proposes a general framework for structural motif discovery. The framework is based on a modular design in which the ponents can be modified or replaced independently to increase its applicability to various studies. It is a two-stage approach that first converts protein 3D structures into structural alphabet sequences, and then applies a sequence motif-finding tool to these sequences to detect conserved motifs. We named the structural motif database we built the SA-Motifbase, which provides the structural information conserved at different hierarchical levels in SCOP. For each motif, SA-Motifbase presents its 3D view; alphabet letter preference; alphabet letter frequency distribution; and the significance. SA-Motifbase is available at |
22099702 | Intron identification approaches based on weighted features and fuzzy decision trees. | putational predictions of splice sites largely depend on the sequence patterns of known intronic sequence features (ISFs) described in the classical intron definition model (IDM). putation-oriented IDM (CO-IDM) clearly provides more specific and concrete information for describing intron flanks of splice sites (IFSSs). In the paper, we proposed a novel approach of fuzzy decision trees (FDTs) which utilize (1) weighted ISFs of twelve uni-frame patterns (UFPs) and forty-five multi-frame patterns (MFPs) and (2) gain ratios to improve the performances in identifying an intron. First, we fuzzified extracted features from genomic sequences using membership functions with an unsupervised self-organizing map (SOM) technique. Then, we brought in different viewpoints of globally weighting and crossly referring in generating fuzzy rules, which are interpretable and useful for biologists to verify whether a sequence is an intron or not. Finally, the experimental results revealed the effectiveness of the proposed method in improving the identification accuracy. Besides, we also implemented an on-line intronic identifier to infer an unknown genomic sequence. |
22099697 | Orthostatic hypotension: a common, serious and underrecognized problem in hospitalized patients. | Orthostatic hypotension (OH) is strongly age-dependent, with a prevalence ranging from 5% to 11% in middle age to 30% or higher in the elderly. It is also closely associated with mon chronic diseases, including hypertension, congestive heart failure, diabetes mellitus, and Parkinson's disease. Most studies of OH have been performed in population cohorts or elderly residents of extended care facilities, but in this review, we draw attention to a problem little studied to date: OH in hospitalized patients. The prevalence of OH in all hospitalized patients is not known because most studies have included only older individuals with orbid diseases, but in some settings as many as 60% of hospitalized adults have postural hypotension. Hospitalized patients are particularly vulnerable to the consequences of OH, particularly falls, because postural blood pressure (BP) regulation may be disturbed by mon acute illnesses as well as by bed rest and drug treatment. The temporal course of OH in hospitalized patients is uncertain, both because the reproducibility of OH is poor and because conditions affecting postural BP regulation may vary during hospitalization. Finally, OH during hospitalization often persists after discharge, where, in addition to creating an ongoing risk of falls and syncope, it is strongly associated with risk of incident plications, including myocardial infarction, heart failure, stroke, and all-cause mortality. Because OH is mon, easily diagnosable, remediable condition with important clinical implications, we encourage caregivers to monitor postural BP change in patients throughout hospitalization. |
22099703 | Pretreatment of microcrystalline cellulose in organic electrolyte solutions for enzymatic hydrolysis. | Previous studies have shown that the crystalline structure of cellulose is negatively correlated with enzymatic digestibility, therefore, pretreatment is required to break down the highly ordered crystalline structure in cellulose, and to increase the porosity of its surface. In the present study, an organic electrolyte solution posed of an ionic liquid (1-allyl-3-methylimidazolium chloride ([AMIM]Cl)) and an organic solvent (dimethyl sulfoxide; DMSO) was prepared, and used to pretreat microcrystalline cellulose for subsequent enzymatic hydrolysis; to our knowledge, this is the first time that this method has been used. |
22099704 | Prodromes and coping types in bipolar patients with nonpsychotic or psychotic mania. | Bipolar disorder is a recurrent and cyclical illness frequently panied by psychotic symptoms. Detecting prodromes and enhancing coping skills for prodromal symptoms in bipolar patients are very important for relapse prevention. Psychotic features in bipolar patients are related to poor prognosis. We aimed to investigate the differences in prodromal symptoms and coping styles in psychotic and nonpsychotic bipolar patients. |
22099706 | The inhibition of the integrin VLA-4 in MV3 melanoma cell binding by non-anticoagulant heparin derivatives. | The integrin VLA-4-mediated binding is important for the metastatic dissemination of melanoma cells. Recently we found that heparin possesses a binding capacity to VLA-4. This could contribute to the heparin function to attenuate metastasis in a selectin-dependent manner. Aiming to a purposive, anti-adhesive heparin application, structural requirements of heparin for VLA-4 recognition have to be elucidated. |
22099707 | Circulating tissue factor positive microparticles in patients with acute recurrent deep venous thrombosis. | Circulating tissue factor positive microparticles (MPTF) were reported in a wide range of diseases with thrombotic tendency. Though D-dimer assay had a high negative predictive value for deep venous thrombosis (DVT) recurrence, there are currently no reliable positive predictors for recurrent DVT. We therefore quantified MPTF in patients with acute recurrent DVT to determine whether MPTF levels could be used to predict recurrent DVT. |
22099708 | Health care reform: 2012 update. | The recent landmark health care reform legislation seeks to expand health insurance coverage, change incentives, and improve the quality and flow of information. This article reviews the elements of health care reform most relevant to clinical gastroenterology, discusses the ongoing challenges that health care reform legislation faces, and considers the potential implications for clinical practice. |
22099710 | Impact of health care reform on academic medical centers. | The impact of health care reform on academic medical centers will be just as great as it is munity practices. The economics of academic medical centers and training programs has been challenging, and will e even more so as funding is cut and the demand for regional integrated systems mounts. This article is one of the first to articulate these challenges and is written by authors well positioned to understand this arena. |
22099711 | Gastroenterologists and accountable care organizations. | Within the Patient Protection and Affordable Care Act of 2010 is a provision setting up a program for the implementation of accountable care organizations (ACOs). This article explains the proposed ACO model and discusses major implications regarding this model of health care reform including the following: What will it take to implement the program successfully? What are the opportunities for savings under the model? What are the potential downfalls of the program as proposed? What impact would the implementation of an ACO have on the practice of gastroenterology? |
22099712 | Electronic medical records and the gastroenterologist. | This is an age of disruptive innovation in health care in which the business model is changing. Fee-for-service, volume-based systems are being replaced by fixed-fee, value-based systems. One of the major facilitating forces behind this change has been the development of the electronic health record, which is providing the munity with the ability to have real-time quality metrics that will drive the development of web-based clinical decision support tools that will transform the current peer-review-based rules of practice with an eclectic fluid environment of continuous quality measurement and improvement. |
22099713 | A letter to fellows: transitioning from training into practice in uncertain times. | The end of training marks the beginning of learning. Moving into practice is exciting, and there are good opportunities. Although there is still a great deal of uncertainty with the economy, you have a skill set that is in demand. By understanding your real priorities, being deliberate and organized in your search, and being willing to extend outside fort zone, you will find a practice that fits you. Each person has an ideal practice. Choose your new practice setting with your eyes wide open, especially regarding new changes that are expected with health care reform. |
22099714 | Medical practice integration: going big in private practice. | Historically, gastroenterologists entered into solo, small group, or academic practices. The current economic environment and looming regulatory mandates have led to gastroenterologists integrating into large, single-specialty groups to acquire costly practice infrastructure, gain negotiating leverage with health plans, promote high-quality care, and benefit from professional practice management. Individual gastroenterologists must assess whether a large practice will meet their personal goals, financial needs, and professional visions. The decision to integrate into a large practice will also be affected by local practice patterns and regulatory issues. For these and other reasons, gastroenterologists are going big in private practice. |
22099716 | The impact of health reform on gastroenterology reimbursement. | The budgetary impact of the cost of health care on the United States economy is far-reaching. An understanding of the provisions in the Affordable Care Act is essential to preparing one's practice to proactively deal with a rapidly changing and evolving system whereby local, regional, and national actions are affecting the ability of clinicians to maintain success on a daily basis. |
22099715 | Gastroenterologists and the triple aim: how to become accountable. | US medicine is fragmented and economically unsustainable and has vast opportunities for quality improvement. A current solution is to create large accountable care organizations. Fragmentation should be reduced and clinical coordination be improved, which means that gastroenterologists and other specialists will be challenged to change practices from traditional reactive and consultative care to a principal care model in which they manage appropriate clinical service lines. The pay-off in improved patient care and financial stability can be substantial. This article discusses a proposed evolution toward clinical service line management that might be achieved by an independent single specialty practice. |
22099718 | The gastroenterologist and industry: changing winds. | The medical device and pharmaceutical industry is facing mounting pressure to produce cost-effectiveness and clinical-effectiveness data in order for their products to be acceptable for approval by the Federal Drug Administration and then for payer reimbursement. The implications of these increasing burdens on our field will e apparent in everyday practice. This article outlines these challenges and discusses possible ways to improve the situation. |
22099717 | The impact of health care reform on innovation and new technology. | Health care reform has created special challenges and hurdles to the introduction of new technology and innovative medical devices in gastroenterology and other medical fields. The implication of new regulations will be enormous as we begin to see venture-capital funding flee our specialty for more lucrative and "sure bets." This article, written by an experienced entrepreneur and practicing gastroenterologist, outlines some of the implications of this emerging challenge. Few other sources of information are available that truly articulate the insider view ing changes. |
22099719 | Demonstrating value: registries and beyond. | Patient registries have evolved to support goals within medical specialties that have traditionally fallen outside their core missions. Quality measurement and reporting can support payor advocacy, meet federal and state requirements, evolve practices into novel care environments, and facilitate coordination among multiple health care providers. Registries can additionally be of use in safety and event monitoring, and parative effectiveness research. Through integration with electronic health records, registries also serve as a vehicle for the delivery of guidelines and the implementation of decision support and care pathways. |
22099722 | Cognitive behaviour therapy and supportive therapy for bipolar disorders: relapse rates for treatment period and 2-year follow-up. | The efficacy of adjunctive psychosocial interventions such as cognitive behaviour therapy (CBT) for bipolar disorder (BD) has been demonstrated in several uncontrolled and controlled studies. However, these pared CBT to either a waiting list control group, brief psycho-education or treatment as usual (TAU). Our primary aim was to determine whether CBT is superior to supportive therapy (ST) of equal intensity and frequency in preventing relapse and improving e at post-treatment. A secondary aim was to look at predictors of survival time. |
22099723 | GM-CSF-induced regulatory T cells selectively inhibit anti-acetylcholine receptor-specific immune responses in experimental myasthenia gravis. | We and others have demonstrated the ability of granulocyte-macrophage colony-stimulating factor (GM-CSF) to suppress autoimmunity by increasing the number of CD4(+)CD25(+) regulatory T cells (Tregs). In the current study, we have explored the critical role of induced antigen specific Tregs in the therapeutic effects of GM-CSF in murine experimental autoimmune myasthenia gravis (EAMG). Specifically, we show that Tregs from GM-CSF treated EAMG mice (GM-CSF/AChR-induced-Tregs) adoptively transferred into animals with EAMG suppressed clinical disease more potently than equal numbers of Tregs from either GM-CSF untreated EAMG mice or healthy mice treated with GM-CSF. In addition, GM-CSF/AChR-induced-Tregs selectively suppressed antigen specific T cell proliferation induced by AChR relative to that induced by an irrelevant self antigen, (thyroglobulin) and failed to significantly alter T cell proliferation in response to an exogenous antigen (ovalbumin). These results are consistent with the hypothesized mechanism of action of GM-CSF involving the mobilization of tolerogenic dendritic cell precursors which, upon antigen (AChR) capture, suppress the anti-AChR immune response through the induction/expansion of AChR-specific Tregs. |
22099725 | A multidisciplinary team approach to hydroxyurea-associated chronic wound with squamous cell carcinoma. | Hydroxyurea (HU) has been shown to induce a variety of cutaneous adverse reactions, including severe leg ulcers. This report shows a successful treatment of a HU-induced chronic wound associated with squamous cell carcinomas (SCC). A 62-year-old patient affected with polycythemia vera and treated with HU for 10 years, presented with a non healing ulcer on a left heel. The patient gave a history of suffering from the wound for over 2 years. Biopsy showed evidence of invasive SCC. The patient underwent Mohs surgery and a greater saphenous vein ablation for polycythemia vera-associated plications. The wound consistently decreased in size following successive debridements and coverage with human skin equivalent. The wound pletely after a 6-month period. A multidisciplinary team approach to the treatment proved to be effective resulting in healing of this multifactorial chronic ulcer. |
22099726 | Parents' ability to recall past injuries to maxillary primary incisors in their children. | To evaluate the ability of parents to recall past injuries to their children's maxillary primary incisors. |
22099727 | New perspectives in the treatment of metastatic renal cell carcinoma. | Since 2007, the advent of so-called "targeted" therapy has revolutionized the management of renal cell carcinoma (RCC), replacing interferon or interleukin-2 immunotherapy. The present article first reviews the fundamentals of current practice in the management of metastatic-phase RCC. It then goes on to consider the new perspectives opening up in terms of treatment strategy (sequential bined treatments and new drugs) in what can be seen as a second phase in this ongoing revolution in treatment. In the years e, the challenge will be to learn to optimize the use of the many drugs available, possibly in association with micro-invasive techniques, so as to achieve the third phase of the revolution: long-term remission in metastatic RCC. The search for factors predictive of response and greater knowledge of tumor biology will be essential steps, yet to be made, toward this goal. |
22099730 | Premature thelarche in infants and toddlers: prevalence, natural history and environmental determinants. | The aim of this study was to measure the prevalence of premature thelarche in infant and toddler girls and to determine if environmental sources of estrogen were associated with early breast development. |
22099731 | Obstetric and perinatal outcomes of teenage pregnancies in Thailand. | To determine whether, when controlling for confounding factors, there was still an association of adolescence with adverse es. |
22099732 | Advance provision of emergency contraception in an urban pediatric emergency department. | To assess whether a policy and educational intervention in an urban, pediatric emergency department (ED) increases advance provision of emergency contraception (EC) to patients. |
22099733 | A comparison of the prevalence of premenstrual dysphoric disorder and comorbidities among adolescents in the United States of America and Nigeria. | Premenstrual dysphoric disorder (PMDD) often starts in adolescence, but there are limited data on its prevalence. The specific aims of this study were to (1) describe the prevalence of PMDD in adolescents presenting to clinics in the midwestern United States and 2 Nigerian cities, (2) identify cultural differences, and (3) screen orbidities. |
22099734 | Teenage pregnancy and the influence of paternal involvement on fetal outcomes. | We sought to assess the impact of paternal involvement on adverse birth es in teenage mothers. |
22099740 | Network of contacts between cattle herds in a French area affected by bovine tuberculosis in 2010. | France attained 'Officially Tuberculosis-Free' status in 2000. However, the Côte d'Or department (a French administrative unit) has since seen an increase in bovine tuberculosis (bTB) cases, with 35% of cases attributed to neighbourhood contamination. The aim of this study was to investigate the characteristics of neighbourhood contacts in an area affected by bTB in 2010, through the use of social network methods. We carried out a survey to determine the frequency and distribution of between-herd contacts in an area containing 22 farms. Contacts were weighted, as not all types of contact carried the same risk of bTB transmission. Cattle movement was considered to be associated with the highest risk, but was not observed within the studied area during the study period. Contact with wild boars was the most frequent type of contact, but was associated with a very low risk. Direct cattle-to-cattle contacts in pasture and contacts with badger latrines were less frequent, but entailed a greater risk of M. bovis transmission. Centrality values were heterogeneous in these two networks. This would enable the disease to spread more rapidly at the start of epidemics than in a perfect randomly mixed population. However, this situation should also result in the total number of infected herds being smaller. We attributed 95% of the contacts to direct contact in pasture or contact with wild boars or badger latrines. Other kinds of contact occurred less frequently (equipment sharing, cattle straying) or did not occur at all (attendance at a show). Most of the contact types were correlated, but none was sufficient in itself to account for all contacts between one particular farm and its neighbours. Contacts with neighbours therefore represent a challenge for the implementation or improvement of control measures. |
22099742 | Perinatal and psychosocial circumstances associated with risk of attempted suicide, non-suicidal self-injury and psychiatric service use. A longitudinal study of young people. | Past studies using large population based datasets link certain perinatal circumstances (birth weight, parity, etc) with mental health es such as suicide, self-harm and psychiatric problems. Problematically, population datasets omit a number of social confounds. The aim of this study is to replicate past research linking perinatal circumstances and mental health (suicidality and use of psychiatric services) and to determine if such associations remain after adjusting for social circumstances. |
22099743 | The relationship between glutathione peroxidase and bioimpedance parameters in nondiabetic hemodialysis patients. | There is growing evidence from experimental and clinical studies that oxidative stress is involved in the pathogenesis of malnutrition. This cross-sectional study aimed to investigate the relationship between glutathione peroxidase (GPx) levels as a marker of antioxidant status and the nutritional status assessed by bioimpedance analysis (BIA). Ninety-seven nondiabetic stable outpatient uremic adults undergoing chronic hemodialysis (HD) were recruited for this study. Impedance measurements were performed using a multifrequency bioelectrical impedance analyzer after dialysis. GPx levels correlated with intracellular water (ICW) (r = 0.341, P = 0.011), ICW/total body weight (r = 0.320, P = 0.017), lean body mass (r = 0.300, P = 0.026) and total body cell mass (r = 0.339, P = 0.011). When patients were divided into two groups according to mean GPx levels (83.9 U/gr hemoglobin), the patients with higher GPx (GPx > 83.9 U/gr hemoglobin) had higher albumin (P = 0.038), lean body mass (P = 0.026), ICW (P = 0.011), and total body cell mass (P = pared with those with lower GPx (GPx ≤ 83.9 U/gr hemoglobin). Furthermore, in the patients with higher GPx, body fat; extracellular water/total body water; illness marker and body fat mass index were lower than other group. In conclusion, our results reveal correlation indicating a relationship between antioxidant status (as measured by GPx) and nutritional status as assessed by BIA in nondiabetic HD patients. |
22099745 | High-mobility group box 1 expressions in hypoxia-induced damaged mouse islets. | Discovering a new, accurate, and useful damage marker for isolated islets is critical for avoiding the transplantation of nontherapeutic preparations. Recently, we have reported that islets that contained uniquely high levels of high-mobility group box 1 (HMGB1) protein and cytokine induced damaged islets released HMGB1 in a mouse model. Islets are frequently exposed to hypoxic conditions during organ procurement, organ transportation, islet isolation, and islet storage before transplantation. In the present study, we analyzed HMGB1 expressions in hypoxia-induced damaged mouse islets. |
22099746 | An effective method to release human islets from surrounding acinar cells with agitation in high osmolality solution. | Islet purification is mainly performed by the density gradient method. However, purification of the embedded islets that are surrounded by exocrine tissue should be difficult, because their density is similar to exocrine tissue. In this study, we performed chart review to assess the relationship between the ratio of embedded islets and efficacy of purification. Then, we tested several conditions of a new method to free the islets from surrounded exocrine tissues using high osmolality solution with gentle agitation. |
22099741 | [Safety and effectiveness of salvage therapy in HIV patients]. | The treatment used after failure of at least two lines of antiretroviral treatment in HIV patients is called salvage therapy. The study aims to describe the characteristics of HIV patients subjected to such a regimen, and determine the safety and effectiveness of treatment with tipranavir (TPV), darunavir (DRV), enfuvirtide (ENF) and etravirine bined with an optimised antiretroviral regimen. |
22099747 | Coculture of hepatocytes with islets. | Bioartificial liver support (BAL) systems are potential new therapeutic approaches for use as liver support to prevent nutrient deficiencies, hypoxia, or ischemia before the acquisition of donated organs. To investigate whether islets are beneficial for hepatocyte function and survival, we cocultured BALB/c mouse islets with C57BL/6J hepatocytes to assess hepatocyte viability, function, and apoptosis. We observe cell viability to decrease progressively by 50% from day 0 to day 3 among isolated hepatocytes (group A) and hepatocytes cocultured with islets (group B). However, group A was prone to necrosis and reduced albumin secretion during culture. In contrast, at day 7 group B maintained albumin secretion (0.3351 ± 0.0581 vs 0.1451 ± 0.0329 μg/h/mL; P < .05). Early apoptosis was observed at day 3 among group A but at day 7 in group B. In addition, quantitative analysis of the apoptotic cells revealed group B to show a delayed phenotype of both early and late pared with group A. Our results indicated that islets could retain hepatocyte function and delay apoptosis, suggesting that the coculture system is potentially applicable to develop a high-performance BAL. |
22099748 | Characterization and functional assessment of Clostridium histolyticum class I (C1) collagenases and the synergistic degradation of native collagen in enzyme mixtures containing class II (C2) collagenase. | Clostridium histolyticum expresses two classes of collagenases, C1 and C2. However, degradation of these enzymes by proteases during the fermentation or purification process may lead to numerous molecular forms that lead to inconsistent release of islets from human pancreata. This report defines the amino acid sequence of the truncated forms of C1 (C1b or C1c) that contain a single collagen-binding domain (CBD) and investigates the synergy between the different forms of C1 collagenase and C2 to degrade native collagen. |
22099749 | Effect of synthetic protease inhibitor gabexate mesilate on attenuation of coagulant activity and cytokine release in a rat model of islet transplantation. | The instant blood-mediated inflammatory reaction (IBMIR), in which the activation of coagulation cascade plays a key role, is one of the serious obstacles to successful islet engraftment. Gabexate mesilate (GM) is well known to elicit anticoagulant and antiinflammatory effects. The aim of this study was to evaluate the effect of GM on syngeneic IBMIR. |
22099750 | Expression of receptors for anaphylatoxins C3a and C5a on rat islet preparations. | Complement activation has been implicated in the development of the instant blood-mediated inflammatory reaction (IBMIR). In particular, anaphylatoxins C3a and C5a elicit a broad range of proinflammatory effects, including chemotaxis of inflammatory cells and cytokine release. We have previously shown that 2 types of receptors for C5a are expressed on isolated islets. In the present study, we investigated ponent in detail. |
22099751 | Cryo-isolation: a novel method for enzyme-free isolation of pancreatic islets involving in situ cryopreservation of islets and selective destruction of acinar tissue. | A ponent of treating type I diabetes by transplantation is the availability of sufficient high-quality islets. Currently, islets can be obtained only by reliance on an expensive, inconsistent, and toxic enzyme digestion process. As an alternative, we hypothesize that cryobiologic techniques can be used for differential freeze destruction of the pancreas to release islets that are selectively cryopreserved in situ. |
22099752 | A scalable microfluidic device for the mass production of microencapsulated islets. | The objective of this research was to test the viability and function of islets microencapsulated using a scalable microfluidic device that is suitable for the mass production of encapsulated islets for transplantation. A 3-D microfluidic device consisting of eight outlets with an inner fluid inlet and an outer concentric inlet to the device has been designed and fabricated using the stereolithography rapid prototyping technique. Islets were isolated from normal Wistar-Furth rat pancreas using the procedure of collagenase digestion of pancreatic tissue. Following purification, islet suspensions in 1.5% sodium alginate were pumped into the fluid inlet of the microfluidic device, which distributed the flow equally to all the eight channels according to the design. The air plenum pressed air uniformly through the eight concurrent outlets, and with one fluid pump and air source, the device produced eight microencapsulations simultaneously. After encapsulation, the islets were tested for functionality using the dynamic perifusion procedure with low- and high-glucose concentrations. The device is capable of producing eight channels of steady stream of monodisperse microencapsulations of a range of diameters depending on the design and process parameters. Using this prototype device, encapsulated islets were shown to be viable in the functional tests that we performed. Thus, the mean ± standard deviation rate of insulin secretion increased from a basal rate of 0.165 ± 0.059 ng/10 islets/min to a stimulated rate of 0.422 ± 0.095 ng/10 islets/min (P < .05, n = 3), when the glucose concentration was changed from 5.5 mmol/L to 27.5 mmol/L, and this glucose stimulation index was not different from that observed with unencapsulated islets under same conditions. In summary, the high-throughput prototype device that we have designed can produce encapsulated islets that are viable and suitable for transplantation studies. |
22099753 | Production of islet cell sheets using cryopreserved islet cells. | To establish novel islet-based therapies, our group has recently developed technologies to create a contiguous, monolayered sheet made from freshly dispersed islet cells. Islet cell sheets generated from freshly isolated cells are easily transplantable for engraftment into subcutaneous sites in rodents. The use of a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm), grafted culture dishes with laminin-5 coating is an important feature of this process. To expand the utility of this protocol, the present study was performed to assess whether sheets generated using cryopreserved islet cells maintained viability and normal cellular phenotypes. |
22099754 | Instant blood-mediated inflammatory reaction during islet transplantation: the role of Toll-like receptors signaling pathways. | The instant blood-mediated inflammatory reaction (IBMIR) leads to massive destruction of transplanted islets. Islet isolation and time of culture may elicit the release of potent activators of Toll-like receptors (TLRs) signaling pathways during IBMIR. This work sought to evaluate the role of TLR signaling pathways to mediate inflammatory reactions. Isolated rat pancreatic islets were cultured for 12, 24, or 48 hours. Their viability was assessed by fluorescein diacetate/propidium iodide and their functionality, by glucose stimulation tests. Endotoxin levels were quantified using the Limulus Amebocyte Lysate assays. After RNA extraction and reverse transcription, we performed polymerase chain reaction (PCR) arrays. Samples obtained immediately after isolation were defined as controls. Eighty-four genes belonging to the TLR signaling pathways, pared with control samples. After culture, islets were viable and functional with low endotoxin levels (< 0.1 endotoxin units/mL) showed TLR activation not due to exogenous contamination. Analysis of PCR arrays highlighted significant up-regulation of TLR-2. After 24 hours of culture, TLR-2 was up-regulated to 6.8 ± 0.6-fold (P < pared with controls but decreased to 4.3 ± 1.4-fold after 48 hours. In the same way, expression of myeloid differentiation primary response gene 88 (Myd88) was significantly up-regulated (3.2 ± 0.4-fold [P < pared with controls. After 12 hours of culture, interleukin-10 gene expression was significantly up-regulated at 11.6 ± 3.7- fold (P < .05), reaching 17.5 ± 8.3 after 24 hours. Finally, the cyclo-oxygenase-2 gene expression was up-regulated to 509 ± 67.1-fold (P < .05) after 12 hours of culture. These data confirmed the implication of TLR signaling pathways in early inflammatory events. |
22099756 | Modest effects of Fas-ligand and heme oxygenase-1 double transgenic mouse islets on transplantation outcomes. | Interactions of Fas with its ligand (FasL) play an important role in the maintenance of immunologic homeostasis and peripheral tolerance. Heme oxygenase-1 (HO-1) is a protein capable of cytoprotection via radical scavenging and apoptosis prevention. The aim of this study was to test whether overexpression of FasL and HO-1 in murine islets resulted in cell protection and improved functional performance after transplantation. We first generated FasL and HO-1 double transgenic mice to investigate the protective effect of transgenic islets on transplantation. Islets were isolated from FasL and HO-1 double transgenic and nontransgenic Balb/c mice, for transplantation of 300 islets under the left kidney capsule of each streptozotocin-diabetic Balb/c mouse. During 6 weeks after transplantation, the blood glucose gradually decreased in recipients of double transgenic and nontransgenic islets. However, the decrease in blood glucose was more pronounced in the former (450 ± 16 mg/dL at day 0 to 302 ± 55 mg/dL at day 42; P = .01) than the latter (468 ± 17 mg/dL at day 0 to 379 ± 71 mg/dL at day 42; P = .24). The areas under the curve of intraperitoneal glucose tolerance tests at 2, 4, and 6 weeks were not significantly different between recipients of double transgenic and nontransgenic islets. The body weight increased in recipients of double transgenic islets (21.1 ± 1.4 g at day 0 to 26.2 ± 0.8 g at day 42; P = .0002) and nontransgenic islets (21.0 ± 1.4 g at day 0 to 25.1 ± 0.4 g at day 42; P = .0448). Our data suggested modest beneficial effects of transgenic islets with FasL and HO-1 overexpression for transplantation. |
22099755 | Human islet distribution program for basic research at a single center. | The Clinical Islet Laboratory at the University of Alberta/Alberta Health Services distributes human islets for basic research when islet preparations fail to meet defined release criteria for transplantation. This report highlights our islet distribution activity for diabetes research over a 3-year period. Shipments of the acinar-enriched fraction for research were not included in this report. In 2010, we distributed 6.3 million islet equivalents (IEQs) of islets through 127 shipments to 8 researchers, locally, nationally, and internationally. The number of preparations for research use was stable over the 3-year period (26, 23, and 29 preparations in 2008, 2009, and 2010, respectively). Islet yield distributed for research per isolation was 201, 212, and 218 × 10(3) IEQs, respectively. The number of basic researchers was stable as well, although there were only 2 researchers before 2007. Recently, each researcher has received fewer islets per shipment (49,820 IEQs in 2010 vs 75,635 IEQs in 2008) but more frequently (21.5 in 2010 vs 11.2 times per year in 2008). This paradigm shift would be desirable for researchers, because in our experience, most require <30,000 IEQs per shipment, and more frequent islet shipments results in a larger sample size for experimentation. After an initial expansion in the number of researchers requesting islets, our islet distribution activity has remained stable over the years in terms of total productivity of islets utilized for research. The current supply-versus-demand ratio in our program appears to be appropriate. |
22099757 | Role of islet culture on angiogenic and inflammatory mechanisms. | Early events hampering islet engraftment may relate to instant blood-mediated inflammatory reaction (IBMIR) and to insufficient islet revascularization inducing β-cell death. We evaluated the influence of time of culture on angiogenic and inflammatory cellular mechanisms in islet loss in vitro. Rat pancreatic islets cultured for 0, 12, 24, and 48 hours were assessed for functionality using glucose stimulation tests and identification of signaling pathways using polymerase chain reaction (PCR) arrays. Islet functionality decreased significantly immediately. Index of stimulation (IS) was decreased to 2.29 ± 1.05 after 48 hours of culture versus 18.47 ± 4.84 at 0 hours (P < .001). Gene expression studies at 12 hours of culture showed significant overexpression of proinflammatory cytokines and chemokines--interleukin (IL)-6 884.22 ± 282.58 (P < .001) and Cxcl-1 448.09 ± 196.05-fold change (P < .01). Moreover, islets exhibited significant under-expression after 48 hours of genes encoding angiogenic growth factors, such as epidermal growth factor, vascular endothelial growth factor, platelet endothelial cell adhesion molecule 1, a major protein involved in angiogenesis: 0.07 ± 0.02, 0.11 ± 0.08 (P < .001), and 0.17 ± 0.15-fold change (P < .01) respectively. Moreover, tissue inhibitor of metalloproteinases 1, an inhibitor of metallopeptidase, was significantly more over-expressed, namely 54.58 ± 18.08 at 12 hours of culture versus 0.93 ± 0.15/fold change at 0 hours. This study revealed current culture conditions to be deleterious for islet engraftment, possibly due to expression of angiogenic genes and proinflamatory genes during culture. |
22099758 | Subcutaneous transplantation may not be an appropriate approach for the islets embedded in the collagen gel scaffolds. | Synthetic extracellular matrix (ECM) has been shown to be efficient to preserve the function of transplanted islets. In this study using a mouse model, we sought to determine whether subcutaneous transplantation was a convenient procedure for achieving normoglycemia. |
22099759 | Endothelial cells promote pancreatic stem cell activation during islet regeneration in mice. | Diabetes is the clinical consequence of the loss of the majority of the β-cell population and failure to regenerate new pancreatic β cells. The current therapies based on β-cell replacement have failed to achieve β-cell renewal and thus, long-term insulin freedom. We have hypothesized that early rejection of endothelial elements within the islet grafts may seriously hamper islet regeneration in both native and islet grafts. |
22099760 | The effect of epigenetic factors on differentiation of pancreatic progenitor cells into insulin-producing cells. | Differentiation of pancreatic progenitors into insulin-producing β cells is regulated by various transcription factors. To be expressed the genes coding these transcription factors need to be in accessible DNA. Whether a particular gene is present in a form of active euchromatin structure with accessible DNA or in an inactive heterochromatin structure with inaccessible DNA is determined by various epigenetic modifications. We studied the effect of epigenetic modifiers on differentiation of human nonendocrine cells into insulin-producing cells with the aim to evaluate the effect of epigenetic modifications in that process. Within 3 days of cultivation nonendocrine cells form isletlike cell clusters (ILCCs) containing mainly cytokeratin-19-positive cells. After cultivation with epigenetic modifiers and further differentiation, the highest number of C-peptide-positive cells (10.3% ± 2.9%) as well as glucagon-positive cells (7.2% ± 2.8%) was observed in a sample supplemented with bination of 5-Aza-2'-deoxycytidine modifiers, BIX01294 and MC1568. In response to glucose stimulation (5 vs 20 mmol/L) these ILCCs secreted increased amounts of C-peptide (0.45 vs 1.05 pmol C-peptide/μg DNA). Control samples treated without any epigenetic modifiers showed significantly lower numbers of C-peptide-positive cells (3.5% ± 1.6%). These results showed that bination of epigenetic modifiers 5-Aza-2'-deoxycytidine (BIX01294 and MC1568) significantly improved reproducible differentiation of nonendocrine pancreatic cells into insulin-producing cells. |
22099761 | Stimulating β-cell replication and improving islet graft function by AR231453, A GPR119 agonist. | G protein-coupled receptor 119 (GPR119) is predominantly expressed in β cells and intestinal L cells. AR231453 is a selective small-molecular GPR119 agonist that enhances glucose-dependent insulin secretion and glucagon-like peptide 1 (GLP-1) release. We investigated whether AR231453 can directly stimulate β-cell replication and improve islet graft function in diabetic mice. |
22099762 | Assessment of tissue-engineered islet graft viability by fluorine magnetic resonance spectroscopy. | Despite significant progress in the last decade, islet transplantation remains an experimental therapy for a limited number of patients with type 1 diabetes. Tissue-engineered approaches may provide promising alternatives to the current clinical protocol and would benefit greatly from concurrent development of graft quality assessment techniques. This study was designed to evaluate whether viability of tissue-engineered islet grafts can be assessed using fluorine magnetic resonance spectroscopy ((19)F-MRS), by the noninvasive measurement of oxygen partial pressure (pO(2)) and the subsequent calculation of islet oxygen consumption rate (OCR). |
22099763 | Dynamic contrast-enhanced magnetic resonance imaging as a tool to monitor the blood supply to an artificial cavity used as a site for islet transplantation in rats. | The transplantation of islets of Langerhans isolated from one donor pancreas can rarely release a diabetic recipient from insulin injections. The major reason is the destruction of 50%-60% of the transplanted tissue, which proceeds typically within a few hours after the insertion of the islets into the portal vein. Therefore, several groups have focused on development of an artificial site for islet transplantation. The main aim of the present study was to test the efficacy of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to evaluate the blood supply feeding the artificially created cavities for islet transplantation. |
22099764 | Effect of exenatide on gastric emptying and graft survival in islet allograft recipients. | To evaluate the effect of exenatide on gastric emptying and long-term metabolic control. |
22099765 | A precise analysis of C5a inhibitory peptide on inflammatory mediators induced after islet transplantation. | We recently reported that C5a inhibitory peptide (C5aIP) prevents the instant blood-mediated inflammatory reaction by attenuating cross talk plement and coagulation cascades. C5aIP has also been shown to possess a broad range of anti-inflammatory effects. Due to methodological limitations, it is difficult to perform detailed analyses on wide range of inflammatory mediators in rat model. Therefore, we examined whether C5aIP suppressed various inflammatory cytokines induced after islet transplantation using a mouse model. |
22099766 | Assessment for revascularization of transplanted pancreatic islets at subcutaneous site in mice with a highly sensitive imaging system. | The subcutaneous space is one of the ideal sites for pancreatic islet transplantation, owing to the minimal invasiveness and easy access. However, the results of pancreatic islet transplantation in subcutaneous sites remain unsatisfactory. One of the main obstacles to successful pancreatic islet transplantation in subcutaneous sites is poor revascularization. Therefore, the aim of this study was to evaluate the revascularization process at subcutaneous sites with a highly sensitive imaging bining a dorsal skinfold chamber (DSC) technique and multiphoton laser scanning microscopy (MPLSM). |
22099767 | Studies of circulating microparticle release in peripheral blood after pancreatic islet transplantation. | The loss of graft function after intraportal islet transplantation is likely multifactorial involving allogeneic rejection, recurrent autoimmunity, graft exhaustion due to a marginally implanted islet mass, immunosuppressant toxicity, and impaired β-cell regeneration. Because early markers of the loss of β-cell mass or function are lacking, monitoring of islet function remains a challenging issue. We have reported herein monitoring of membrane procoagulant microparticles (MPs) as markers of cell stress in the plasma of three recipients with various clinical histories. Early kinetics of C-peptide and MPs followed identical patterns during the first weeks after transplantation; a major increase probably reflected processes related to cell infusion and islet engraftment. Importantly in the case of rejection, MPs and C-peptide showed opposite patterns. A fall in C-peptide was associated with enhanced insulin needs. Our results suggested that a peak in MP levels might indicate rejection with prognotic value. Treatment of the loss of islet function by a new islet infusion or steroid therapy returned MP and C-peptide levels to their baselines with itant restoration of islet function. In the patient with suspected acute cellular rejection, MPs also appeared to be sensors of immunosuppressive steroid therapy. |
22099768 | Usefulness of the secretory unit of islet transplant objects (SUITO) index for evaluation of clinical autologous islet transplantation. | Assessing the engrafted islet mass is important in evaluating the efficacy of islet transplantation. We previously demonstrated that the average secretory unit of islet transplant objects (SUITO) index within 1 month of allogeneic islet transplantation was an excellent predictor of insulin independence. However, the usefulness of the SUITO index for evaluating autologous islet transplantation has not been explored. The purpose of the present study was to assess the relationship between the SUITO index and clinical es after total pancreatectomy followed by autologous islet transplantation. |
22099769 | Association between the secretory unit of islet transplant objects index and satisfaction with insulin therapy among insulin-dependent islet recipients. | When patients do not e insulin independent after islet cell transplantation (ICT), another aim is to eliminate severe hypoglycemia. Previously we reported that a secretory unit of islet transplant objects (SUITO) index score >10 was associated with a reduction of severe hypoglycemia. In this study, we assessed patients' satisfaction with their insulin therapy based on the SUITO index. |
22099771 | New alginate microcapsule system for angiogenic protein delivery and immunoisolation of islets for transplantation in the rat omentum pouch. | Severe hypoxia caused by a lack of vascular supply and an inability to retrieve encapsulated islets transplanted in the peritoneal cavity for biopsy and subsequent evaluation are obstacles to clinical application of encapsulation strategies for islet transplantation. We recently proposed an omentum pouch model as an alternative site of encapsulated islet transplantation and have also described a multi-layer microcapsule system suitable for coencapsulation of islets with angiogenic protein in which the latter could be encapsulated in an external layer to induce vascularization of the encapsulated islet graft. The purpose of the present study was to determine the angiogenic efficacy of fibroblast growth factor (FGF-1) released from the external layer of the new capsule system in the omentum pouch graft. We prepared 2 groups of alginate microspheres, each measuring ∼600 μm in diameter with a semipermeable poly-L-ornithine (PLO) membrane separating 2 alginate layers. While one group of microcapsules contained no protein (control), FGF-1 (1.794 μg/100 microcapsules) was encapsulated in the external layer of the other (test) group. From each of the 2 groups, 100 microcapsules were transplanted separately in an omentum pouch created in each normal Lewis rat and were retrieved after 14 days for analysis of vessel density using the technique of serial sample sections stained for CD31 with quantitative three-dimensional imaging. We found that FGF-1 released from the external layer of the test microcapsules induced a mean ± SD vessel density (mm(2)) of 198.8 ± pared with a density of 128.9 ± 10.9 in pouches measured in control capsule implants (P = .03; n = 5 animals/group). We concluded that the external layer of our new alginate microcapsule system is an effective drug delivery device for enhancement of graft neovascularization in a retrievable omentum pouch. |
22099773 | Ten years of simultaneous pancreas-kidney transplantation: a retrospective single-center analysis of prospectively obtained data. | Simultaneous pancreas-kidney transplantation (SPK) is a standardized and life-saving procedure for a patient suffering from both insulin-dependent diabetes mellitus type 1 (IDDM 1) and end-stage diabetic nephropathy. To expand the donor pool and to determine the influence of the preprocurement pancreas suitability scoring system (P-PASS) on pancreas graft survival we retrospectively analyzed our data on SPK. |