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Methylene Blue (methylene + blue)
Terms modified by Methylene Blue Selected AbstractsMETHYLENE BLUE IN PILONIDAL SINUS SURGERYANZ JOURNAL OF SURGERY, Issue 7 2007FRCSEd, FRCSI, Mohamed Ezzedien Rabie MSc No abstract is available for this article. [source] New Methylene Blue (NMB) Encapsulated in Mesoporous AlMCM-41 Material and Its Application for Amperometric Determination of Ascorbic Acid in Real SamplesELECTROANALYSIS, Issue 15 2007Shabnam Sohrabnezhad Abstract New methylene blue (NMB) dye incorporated into AlMCM-41 surfactant-free and hybrid surfactant-AlMCM-41 mesophase. UV-vis evidence shows that new methylene blue dye protonated in both cases of zeolites. New methylene blue is electroactive in zeolites and their electrochemical activity has been studied by cyclic voltammetry and compared to that of NMB in aqueous solutions. New methylene blue molecules are not released to the solution during CV measurements and are accessible to H3O+ ions. The presence of surfactant affects the kinetics of the redox process through proton ions diffusion. The midpoint potentials (Em) values show that new methylene blue dye incorporated into AlMCM-41 can be reduced easily with respect to solution new methylene blue. New methylene blue interacting with surfactant polar heads and residual Br, ions as a results, it shows a couple of peaks in high potential with respect to new methylene blue solution. The electrode made with methylene blue-AlMCM-41 without surfactant was used for the mediated oxidation of ascorbic acid. The anodic peak current observed in cyclic voltammetry was linearly dependent on the ascorbic acid concentration. The calibration plot was linear over the ascorbic acid concentration range 1.0×10,5 to 5.0×10,4 M. The detection limit of the method is 1.0×10,5 M, low enough for trace ascorbic acid determination in various real samples. [source] Label-Free and Label Based Electrochemical Detection of Hybridization by Using Methylene Blue and Peptide Nucleic Acid Probes at Chitosan Modified Carbon Paste ElectrodesELECTROANALYSIS, Issue 24 2002Pinar Kara Abstract A chitosan modified carbon paste electrode (ChiCPE) based DNA biosensor for the recognition of calf thymus double stranded DNA (dsDNA), single stranded DNA (ssDNA) and hybridization detection between complementary DNA oligonucleotides is presented. DNA and oligonucleotides were electrostatically attached by using chitosan onto CPE. The amino groups of chitosan formed a strong complex with the phosphate backbone of DNA. The immobilized probe could selectively hybridize with the target DNA to form hybrid on the CPE surface. The detection of hybridization was observed by using the label-free and label based protocols. The oxidation signals of guanine and adenine greatly decreased when a hybrid was formed on the ChiCPE surface. The changes in the peak currents of methylene blue (MB), an electroactive label, were observed upon hybridization of probe with target. The signals of MB were investigated at dsDNA modified ChiCPE and ssDNA modified ChiCPE and the increased peak currents were observed, in respect to the order of electrodes. The hybridization of peptide nucleic acid (PNA) probes with the DNA target sequences at ChiCPE was also investigated. Performance characteristics of the sensor were described, along with future prospects. [source] Formation of Poly(propylene)-Based Biocomposite Films and Their Use in the Attachment of Methylene BlueMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2010Jesica A. Cavallo Abstract Biocomposite PP -g- PAAc-CS films based on PP were generated and utilized as support of methylene blue, a thiazidic dye. Using a photograft polymerization of acrylic acid, the PP film was functionalized with carboxyl groups (PP -g- PAAc), which attached chitosan by electrostatic bond. A longer poly(acrylic acid) chain or a higher CS immobilization temperature led to a higher chain interpenetration and crosslinking reaction. Immobilized MB confirmed to possess redox activity from its reaction with ascorbic acid, where the dye decomposition rate () increases together with the chain interpenetration, then decreasing with the increase in the crosslinking degree. [source] Binding of Methylene Blue to Polyelectrolytes Containing Sulfonate GroupsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 13-14 2009Ignacio Moreno-Villoslada Abstract The interaction between methylene blue (MB) and poly(sodium 4-styrenesulfonate) (PSS), poly(sodium vinylsulfonate) (PVS), and the more hydrophobic poly[sodium 2-(N -acrylamido)-2-methyl-propanesulfonate] (PAMPS), is investigated. The main driving forces for the interaction with PSS are supposed to be short-range aromatic/aromatic interactions, which explain the smaller dissociation constant, the resistance to the cleaving effect of NaCl, and the prevention of MB self-aggregation around the macromolecules under a moderate excess of the polymer. On the contrary, as a consequence of long-range interactions, a higher local concentration of MB around PAMPS and, more significantly, around PVS results in MB self-aggregation that can be quenched in the presence of NaCl. [source] Energy Transfer from Chemically Attached Rhodamine 101 to Adsorbed Methylene Blue on Microcrystalline Cellulose Particles,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2007Hernán B. Rodríguez Rhodamine 101 (R101) was chemically attached onto microcrystalline cellulose and methylene blue (MB) was adsorbed to a sample bearing nearby 6 × 10,7 mol R101 (g cellulose),1. The system was studied by reflectance and emission spectroscopy in the solid state. R101 shows no aggregation in these conditions and, while pure MB builds up dimers on cellulose even at 2 × 10,8 mol g,1, in the presence of R101 no evidence on selfaggregation or heteroaggregation is found up to around 10,6 mol g,1. No exciplex formation is found as well. The overall fluorescence quantum yield measured on thick layers, once re-absorption effects are accounted for, amounts to 0.80 ± 0.07 for pure R101 and decreases steadily on increasing the concentration of MB. Results demonstrate the occurrence of radiative and nonradiative singlet energy transfer from R101 to MB. For thick layers of particles, the combined effect of both kinds of energy transfer amounts to nearly 80% at the highest acceptor concentration, while nonradiative transfer reaches 60% both for thin and optically thick layers. The dependence of nonradiative energy transfer efficiencies on the acceptor concentration is analyzed and the origin of departures from Förster behavior at low acceptor concentration is discussed. [source] Methylene blue attenuates lung injury after mesenteric artery clamping/unclampingEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 6 2004A. A. Weinbroum Abstract Background, This controlled, experimental study was designed to assess the effects of intratracheal and intravenous methylene blue on reperfusion lung injury following superior mesenteric artery clamping/unclamping. Materials and methods, Superior mesenteric arteries of 144 anaesthetized adult male Wistar rats (n = 12/group) were clamped for 1 h. Ten minutes before unclamping, methylene blue or its vehicle was administered intratracheally or intravenously, followed by a 3 h-respiratory assessment and postexperimental assessment of survival. Results, Intravenous 3 and 9 mg kg,1 but not higher methylene blue doses, and intratracheal 6-mg kg,1 but not lower doses, significantly (P < 0·05) reduced the 100% increase in plateau pressure, 30% reduction in PO2/FiO2, fourfold augmented bronchoalveolar lavage-retrieved volume and the increased polymorphonuclear leukocytes/bronchoalveolar cells' ratio associated with unclamping of the superior mesenteric artery. Lung tissue polymorphonuclear leukocytes count, total xanthine oxidase activity and wet-to-dry-weight ratio were also normal in these dose-treated groups. These effective regimens were also associated with longer animal survival. Conclusions, Intratracheal methylene blue mitigates lung reperfusion injury following superior mesenteric artery clamping/unclamping at a similar magnitude as an intravenous regimen. This finding is a novel potential use of methylene blue in vivo. [source] Photogalvanic effect in aqueous Methylene blue nickel mesh systems: Conversion of light into electricityINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2001Ilker S. Bayer Abstract The photogalvanic effect in electrochemical cells, employing aqueous Methylene blue and Fe(II)/Fe(III) couple electrolyte and nickel-mesh electrodes, were experimentally investigated. Five different standard H-cell configurations were set-up by modifying the electrolyte. Long-term open-circuit voltage measurements were conducted in order to test the stability of the cells. Light on,off reproducibility experiments were also carried out during lengthy cell operations. By comparing experimental quantum yield with theoretical predictions, it was found that the cells operate on differential electrode kinetics. Oxidation of the illuminated electrode was detected. This affected the current,voltage characteristics of the cells after a sufficiently long cell operation. Schottky junction treatment was used to model the electrolyte,electrode junction. After calculating the ratio between the majority carrier (electron) current density and minority carrier (hole) current density, we concluded that the oxidation of the electrodes contributes positively to the cell performance since the electrode,electrolyte interface shows unipolar Schottky diode characteristics. Copyright © 2001 John Wiley & Sons, Ltd. [source] Methylene blue inhibits angiogenesis in chick chorioallontic membrane through a nitric oxide-independent mechanismJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 2 2006N. Zacharakis Abstract Angiogenesis is the process of generating new blood vessels from preexisting vessels and is considered essential in many pathological conditions. The purpose of the present study was to evaluate the effect of methylene blue in chick chorioallantoic membrane angiogenesis model in vivo. In this well characterized model, methylene blue inhibited angiogenesis in a concentration-dependent manner. In addition, when methylene blue was combined with sodium nitroprusside, a spontaneous generator of nitric oxide, an inhibition of angiogenesis was evident which was comparable with that observed by the application of methylene blue alone. Sodium nitroprusside, alone, caused a significant inhibition in basal angiogenesis. These results provide evidence that methylene blue inhibits angiogenesis independently of nitric oxide pathway and suggest that methylene blue may be useful for treating angiogenesis-dependent human diseases. [source] Methylene blue-mediated photodynamic therapy induces mitochondria-dependent apoptosis in HeLa CellJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2008Yan Lu Abstract Methylene blue (MB), a widely studied reagent, is investigated in this work for its usage in photodynamic therapy (PDT). PDT has been proved to be highly effective in the treatment of different types of cancers. Previous studies showed MB has both high affinity for mitochondria and high photodynamic efficiency. To elucidate the effects of MB in PDT, we analyzed PDT-induced apoptosis in HeLa cells by introducing different doses of MB into the culture media. Our data showed that MB-mediated PDT triggered intense apoptotic cell death through a series of steps, beginning with photochemical generation of reactive oxygen species. The release of cytochrome c and activation of caspase-3 indicated that MB-PDT-mediated apoptosis in HeLa cells was executed by the mitochondria-dependent apoptotic pathway. Importantly, proteomic studies confirmed that expression levels of several mitochondrial proteins were altered in MB-PDT-induced apoptosis, including TRAP1, mitochondrial elongation factor Tu and peroxiredoxin 3 isoform b. Western blot data showed that phosphorylation of ERK1/2 and PKA were reduced in MB-PDT treated cells, indicating several signal molecules participating in this apoptotic cascade. Moreover, MB-PDT induced an increase in the strength of interaction between Bcl-xL and dephosphorylated Bad. This led to loss of the pro-survival function of Bcl-xL and resulted in mitochondria-mediated apoptosis. This study provides solid evidence of a strong induction by MB-PDT of a mitochondria-dependent apoptosis cascade in HeLa cells. J. Cell. Biochem. 105: 1451,1460, 2008. © 2008 Wiley-Liss, Inc. [source] Nitric oxide induces acrosome reaction in cryopreserved bovine spermatozoaANDROLOGIA, Issue 5 2005P. C. Rodriguez Summary The aim of this work was to study the effect of nitric oxide on acrosome reaction (AR) and the participation of protein kinases and reactive oxygen species in the AR of cryopreserved bovine spermatozoa. Spermatozoa were capacitated in Tyrode's albumin lactate pyruvate medium with heparin (10 IU ml,1) and then incubated with different concentrations of sodium nitroprusside (SNP) (1,200 ,mol l,1). Methylene blue and haemoglobin were used to confirm the role of nitric oxide as an inducer of the AR. The participation of protein kinase A (PKA) , protein kinase C (PKC) and protein tyrosine kinase was evaluated using specific inhibitors of these enzymes (H-89, 50 ,mol l,1; bisindolylmaleimide I, 0.1 ,mol l,1 and genistein, 3 ,mol l,1). The role of hydrogen peroxide or superoxide anion was evaluated by incubation with catalase or superoxide dismutase respectively. AR percentages were determined by the fluorescence technique with chlortetracycline. The highest levels of AR were obtained in capacitated spermatozoa treated with 5,200 ,mol l,1 SNP (24.8 ± 1.8%). The presence of PKA, PKC and protein tyrosine kinase inhibitors likewise decreased AR percentages. The addition of superoxide dismutase had no effect on the AR level but catalase completely blocked it. These results indicate that nitric oxide induces AR in capacitated spermatozoa involving hydrogen peroxide and the participation of PKA, PKC and protein tyrosine kinase as part of the signal transduction mechanism which lead to the AR in cryopreserved bovine spermatozoa. [source] NO/cyclic GMP pathway mediates the relaxation of feline lower oesophageal sphincterAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 3 2003C. H. Jun Summary 1 We examined the role of the NO/cyclic GMP (cyclic GMP) pathway in nitric oxide (NO)- and vasoactive intestinal peptide (VIP)-induced relaxation of feline lower oesophageal sphincter (LES). Furthermore, it was studied whether methylene blue, LY83583 and ODQ, which are soluble guanylate cyclase (sGC) inhibitors, could inhibit NO-induced relaxation. 2 The nitric oxide synthase (NOS) inhibitor, N -nitro- l -arginine (l -NNA) had no effect in sodium nitropruside (SNP)-induced relaxation, but 3-morpholinosydnonimine- N -ethylcarbamide (SIN-1)-induced relaxation was decreased by the pretreatment of l -NNA, which showed that SIN-1, not SNP, could activate NOS to cause relaxation. Methylene blue and LY83583 did not inhibit the relaxation by SNP and SIN-1. However, the more specific sGC inhibitor ODQ blocked the relaxation induced by NO donors. 3 To identify the relationship of NOS, sGC and adenylate cyclase in VIP-induced relaxation, tissue were pretreated with l -NNA and ODQ and SQ22536. These inhibitors produced significant inhibition of this response to VIP. The adenylyl cyclase inhibitor SQ 22536 also inhibited relaxation by VIP. 4 In conclusion, our data showed that SNP- and SIN-1-induced relaxation was mediated by sGC. Of sGC inhibitors, methylene blue and LY83583 were not adequate for the examination of NO donor-induced feline LES smooth muscle relaxation. VIP also caused relaxation by the pathway involving NO and cGMP and cAMP. [source] B2 kinin receptors mediate the Indian red scorpion venom-induced augmentation of visceral reflexes via the nitric oxide cyclic guanosine monophosphate pathwayACTA PHYSIOLOGICA, Issue 4 2009S. Kanoo Abstract Aim:, This study was performed to delineate the kinin (receptor)-dependent pathways in the Indian red scorpion (Mesobuthus tamulus; MBT) venom-induced pulmonary oedema as well as the augmentation of cardio-pulmonary reflexes evoked by phenyldiguanide (PDG). Methods:, In urethane-anaesthetized adult rats, the effect of venom on the PDG reflex responses (blood pressure, heart rate and respiration rate) and the pulmonary water content was ascertained using various antagonists(des- Arg, B1 receptor antagonist; Hoe 140, B2 receptor antagonist; N, -nitro- l -arginine methyl ester (l -NAME), nitric oxide (NO) synthase inhibitor; methylene blue, soluble guanylate cyclase inhibitor; and glibenclamide, K+ATP channel blocker). The effect of phosphodiesterase V inhibitor (sildenafil citrate) on the reflex response and the pulmonary water content was also examined and compared with venom-induced responses. Results:, Intravenous injection of PDG (10 ,g kg,1) evoked apnoea, bradycardia and hypotension lasting >60 s. Exposure to MBT venom (100 ,g kg,1) for 30 min augmented the PDG reflex responses by two times and increased the pulmonary water content, significantly. Hoe 140 blocked the venom-induced responses (augmentation of PDG reflex and increased pulmonary water content) whereas des-Arg did not. l -NAME, methylene blue or glibenclamide also blocked the venom-induced responses. Furthermore, sildenafil citrate (that increases cGMP levels) produced augmentation of PDG reflex response and increased the pulmonary water content as seen with venom. Conclusion:, The results indicate that venom-induced responses involve B2 kinin receptors via the NO-dependent guanylate cyclase-cGMP pathway involving K+ATP channels. [source] Xanthine-analog, KMUP-2, enhances cyclic GMP and K+ channel activities in rabbit aorta and corpus cavernosum with associated penile erectionDRUG DEVELOPMENT RESEARCH, Issue 3 2002Rong-Jyh Lin Abstract The pharmacological properties of KMUP-2 were examined in isolated rabbit aorta and corpus cavernosum smooth muscle (CCSM). KMUP-2 caused relaxations that were attenuated by removed endothelium, high K+, and pretreatment with the soluble guanylate cyclase (sGC) inhibitors methylene blue (10 ,M) and ODQ (1 ,M), a NOS inhibitor, L-NAME (100 ,M), a K+ channel blocker TEA (10 mM), a KATP channel blocker glibenclamide (1 ,M), a voltage-dependent K+ channel blocker 4-AP (100 ,M), and the Ca2+ -dependent K+ channel blockers apamin (1 ,M) and charybdotoxin (ChTX, 0.1 ,M). The relaxant responses of KMUP-2 (0.01, 0.05, 0.1 ,M) together with a PDE inhibitor, IBMX (0.5 ,M), had additive effects on rabbit aorta and CCSM. Additionally, KMUP-2 (100 ,M) also affected cGMP metabolism, due to its inhibiting activity on PDE in human platelets. KMUP-2 (0.1,100 ,M) further induced an increase of intracellular cGMP levels in the primary cultured rabbit aortic and CCSM cells. These increases in cGMP content were abolished in the presence of methylene blue (100 ,M) and ODQ (10 ,M). Obviously, the relaxant effects of KMUP-2 on rabbit isolated tissues are more sensitive in CCSM than in aorta. Moreover, KMUP-2 also stimulated NO/sGC/cGMP pathway and subsequent elevation of cGMP by blockade of PDE and enhanced opening of K+ channels in rabbit aorta and CCSM. KMUP-2 (0.2, 0.4, 0.6 mg/kg), similar to KMUP-1 and sildenafil, caused increases of intracavernous pressure (ICP) and duration of tumescene (DT) in a dose-dependent manner. It is concluded that both the increases of cGMP and the opening activity of K+ channels play prominent roles in KMUP-2-induced aortic smooth muscle and CCSM relaxation and increases of ICP in rabbits. Drug Dev. Res. 55:162,172, 2002. © 2002 Wiley-Liss, Inc. [source] 4-Aminothiophenol Self-Assembled Monolayer for the Development of a DNA Biosensor Aiming the Detection of Cylindrospermopsin Producing CyanobacteriaELECTROANALYSIS, Issue 22 2008Elisabete Valério Abstract The development of a DNA biosensor for the detection of cylindrospermopsin, based on self-assembled monolayers (SAMs) of 4-aminothiophenol, is investigated. SAMs were characterized by electrochemical reductive desorption. Detection of probe immobilization and hybridization has been achieved by cyclic and square-wave voltammetry (SWV), using methylene blue (MB) as electroactive indicator. The SWV data obtained in phosphate buffer, with and without NaCl, after MB accumulation, revealed an increase of the redox indicator current peaks after the hybridization step. This behavior is consistent with MB intercalation into DNA, for high ionic strength media and attributed to electrostatic interactions in the absence of salt. Evidence for surface modification is also provided by atomic force microscopy and ellipsometry. [source] Fabrication, Characterization, and Application of ,Sandwich-Type' Electrode Based on Single-Walled Carbon Nanotubes and Room Temperature Ionic LiquidELECTROANALYSIS, Issue 17 2008Xuzhi Zhang Abstract The much-enhanced electrochemical responses of potassium ferricyanide and methylene blue (MB) were firstly explored at the glassy carbon electrode modified with single-walled carbon nanotubes (SWNT/GCE), indicating the distinct electrochemical activity of SWNTs towards electroactive molecules. A hydrophobic room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), was used as electrode modification material, which presented wide electrochemical windows, proton permeation and selective extraction ability. In consideration with the advantages of SWNTs and RTIL in detecting target molecules (TMs), a novel strategy of ,sandwich,type' electrode was established with TMs confined by RTIL between the SWNT/GCE and the RTIL membrane. The strategy was used for electrochemical detection of ascorbic acid (AA) and dopamine (DA), and detection limits of 400 and 80 fmol could be obtained, respectively. The selective detection of DA in the presence of high amount of AA could also be realized. This protocol presented many attractive advantages towards voltammetric detection of TMs, such as low sample demand, low cost, high sensitivity, and good stability. [source] Paste Electrode Based on Short Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid: Preparation, Characterization and Application in DNA DetectionELECTROANALYSIS, Issue 12 2008Xuzhi Zhang Abstract A paste electrode (SWNT&RTIL PE) has been prepared using carboxylic group-functionalized short single-walled carbon nanotubes (SWNTs) mixed with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6, one kind of room temperature ionic liquid, RTIL). Its electrochemical behavior was investigated by cyclic voltammetry and electrochemical impedance spectroscopy in comparison with the paste electrode using mineral oil as a binder. Results highlighted the advantages of the paste electrode: not only higher conductivity, but also lower potential separation (,Ep), higher peak current (ip) and better reversibility towards dopamine (DA), methylene blue (MB) and K3[Fe(CN)6]. The SWNT&RTIL PE could be used to detect the number of guanine bases and adenine bases contents in per mol oligonucleotides according to the current response in the range of 0.05,2.0,nM. Based on the current response of guanine bases, oligonucleotides could be detected sensitively in the B,R buffer solution with a detection limit of 9.9,pM. The heterogeneous electron transfer rate constant (ks) of guanine bases contents in the oligonucleotides was investigated and its value was 0.90,s,1. In essence the SWNT&RTIL PE showed high sensitivity, reliability, stability and reproducibility for the detection of DNA. [source] New Methylene Blue (NMB) Encapsulated in Mesoporous AlMCM-41 Material and Its Application for Amperometric Determination of Ascorbic Acid in Real SamplesELECTROANALYSIS, Issue 15 2007Shabnam Sohrabnezhad Abstract New methylene blue (NMB) dye incorporated into AlMCM-41 surfactant-free and hybrid surfactant-AlMCM-41 mesophase. UV-vis evidence shows that new methylene blue dye protonated in both cases of zeolites. New methylene blue is electroactive in zeolites and their electrochemical activity has been studied by cyclic voltammetry and compared to that of NMB in aqueous solutions. New methylene blue molecules are not released to the solution during CV measurements and are accessible to H3O+ ions. The presence of surfactant affects the kinetics of the redox process through proton ions diffusion. The midpoint potentials (Em) values show that new methylene blue dye incorporated into AlMCM-41 can be reduced easily with respect to solution new methylene blue. New methylene blue interacting with surfactant polar heads and residual Br, ions as a results, it shows a couple of peaks in high potential with respect to new methylene blue solution. The electrode made with methylene blue-AlMCM-41 without surfactant was used for the mediated oxidation of ascorbic acid. The anodic peak current observed in cyclic voltammetry was linearly dependent on the ascorbic acid concentration. The calibration plot was linear over the ascorbic acid concentration range 1.0×10,5 to 5.0×10,4 M. The detection limit of the method is 1.0×10,5 M, low enough for trace ascorbic acid determination in various real samples. [source] Label-Free and Label Based Electrochemical Detection of Hybridization by Using Methylene Blue and Peptide Nucleic Acid Probes at Chitosan Modified Carbon Paste ElectrodesELECTROANALYSIS, Issue 24 2002Pinar Kara Abstract A chitosan modified carbon paste electrode (ChiCPE) based DNA biosensor for the recognition of calf thymus double stranded DNA (dsDNA), single stranded DNA (ssDNA) and hybridization detection between complementary DNA oligonucleotides is presented. DNA and oligonucleotides were electrostatically attached by using chitosan onto CPE. The amino groups of chitosan formed a strong complex with the phosphate backbone of DNA. The immobilized probe could selectively hybridize with the target DNA to form hybrid on the CPE surface. The detection of hybridization was observed by using the label-free and label based protocols. The oxidation signals of guanine and adenine greatly decreased when a hybrid was formed on the ChiCPE surface. The changes in the peak currents of methylene blue (MB), an electroactive label, were observed upon hybridization of probe with target. The signals of MB were investigated at dsDNA modified ChiCPE and ssDNA modified ChiCPE and the increased peak currents were observed, in respect to the order of electrodes. The hybridization of peptide nucleic acid (PNA) probes with the DNA target sequences at ChiCPE was also investigated. Performance characteristics of the sensor were described, along with future prospects. [source] MCE-electrochemical detection for following interactions of ssDNA and dsDNA with methylene blueELECTROPHORESIS, Issue 11 2009Mario Castańo-Álvarez Abstract The interaction between the organic dye, methylene blue and DNA has been studied by MCE with electrochemical detection. Interaction produces two different signals, one corresponding to free methylene blue and other, for the complex methylene blue,DNA. The hybridization between a ssDNA and a complementary sequence, specific to the severe acute respiratory syndrome virus, has been performed and studied in a thermoplastic olefin polymer of amorphous structure CE-microchip with an end-channel gold wire detector. Moreover, studies with a longer dsDNA, an expression vector involved in the transitory or stable expression in mammals cells, pFLAG-CMV4, has also been performed. [source] Improved methods for carbon adsorption studies for water and wastewater treatmentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2006Wei-chi Ying Abstract An improved method was developed to rank activated carbon in removing organic water pollutants. The simple and standardized evaluation method uses a set of four adsorptive capacity indicators: phenol, iodine, methylene blue, and tannic acid numbers; those four indicator compounds were selected because they cover the molecular size range of most organic water pollutants. An improved microcolumn rapid breakthrough (MCRB) test method was developed from the existing HPMC (high-pressure minicolumn) and RSSCT (rapid small-scale column test) methods by simplifying the experimental procedure and using readily available low-cost pump, sampler, piping, and fittings. This method can be practiced in an ordinary environmental laboratory to select the best carbon, to verify the treatment effectiveness, and to estimate the adsorption treatment cost based on the observed capacity utilization rate for carbon in the adsorber without the problems often encountered with using small and mini traditional columns. The benefits of the four-parameter carbon selection method and the MCRB method were demonstrated by adsorption isotherm and breakthrough data for several indicator compounds and organic water pollutants. These improved methods will enable efficient carbon adsorption studies necessary for more applications of carbon adsorption technology in water and wastewater treatment. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] Photocatalytic degradation of organic dyes in the presence of titanium dioxide under UV and solar light: Effect of operational parametersENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2005Feryal Akbal The photocatalytic degradation of methylene blue and methyl orange have been studied in the presence of titanium dioxide powder illuminated with a 300-W UV lamp. The effect of hydrogen peroxide on the degradation process was also determined. It was found that the color removal efficiency was affected by the concentration of dye, amount of TiO2 added, and the pH of the solution. The degradation of dyes obeys first-order kinetics, with the apparent first-order rate constant increasing with decreasing dye concentration. The rate constants were evaluated as a function of the concentration of dye, amount of TiO2, and pH. © 2005 American Institute of Chemical Engineers Environ Prog, 2005 [source] Photodynamic therapy against cyanobacteriaENVIRONMENTAL TOXICOLOGY, Issue 1 2007M. Drábková Abstract This study explores the use of photosensitizers and reactive oxygen species (ROS) to limit growth of cyanobacteria. We chose 12 phthalocyanines, tetraphenol porphyrine, and methylene blue as compounds producing singlet oxygen. Hydrogen peroxide was chosen as another source of ROS. These compounds were tested using algal toxicity tests in microplates on three cultures of green algae (Pseudokirchneriella subcapitata, Scenedesmus quadricauda, and Chlorella kessleri) and on three cultures of cyanobacteria (Synechococcus nidulans, Microcystis incerta, and Anabaena sp.). Results indicate that photosensitizers and singlet oxygen could be highly toxic for some selected phytoplankton species. Green alga Scenedesmus quadricauda was highly sensitive (EC50 = 0.07 mg/L) to compounds producing singlet oxygen, although it was not sensitive to hydrogen peroxide, which was about 10 times more toxic for cyanobacteria. We conclude that the compounds producing hydroxyl radical species seems to be more promising to treat cyanobacterial blooms than the compounds producing the singlet oxygen. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 112,115, 2007. [source] Methylene blue attenuates lung injury after mesenteric artery clamping/unclampingEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 6 2004A. A. Weinbroum Abstract Background, This controlled, experimental study was designed to assess the effects of intratracheal and intravenous methylene blue on reperfusion lung injury following superior mesenteric artery clamping/unclamping. Materials and methods, Superior mesenteric arteries of 144 anaesthetized adult male Wistar rats (n = 12/group) were clamped for 1 h. Ten minutes before unclamping, methylene blue or its vehicle was administered intratracheally or intravenously, followed by a 3 h-respiratory assessment and postexperimental assessment of survival. Results, Intravenous 3 and 9 mg kg,1 but not higher methylene blue doses, and intratracheal 6-mg kg,1 but not lower doses, significantly (P < 0·05) reduced the 100% increase in plateau pressure, 30% reduction in PO2/FiO2, fourfold augmented bronchoalveolar lavage-retrieved volume and the increased polymorphonuclear leukocytes/bronchoalveolar cells' ratio associated with unclamping of the superior mesenteric artery. Lung tissue polymorphonuclear leukocytes count, total xanthine oxidase activity and wet-to-dry-weight ratio were also normal in these dose-treated groups. These effective regimens were also associated with longer animal survival. Conclusions, Intratracheal methylene blue mitigates lung reperfusion injury following superior mesenteric artery clamping/unclamping at a similar magnitude as an intravenous regimen. This finding is a novel potential use of methylene blue in vivo. [source] Effect of nitric oxide and NO synthase inhibition on nonquantal acetylcholine release in the rat diaphragmEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2000M. R. Mukhtarov Abstract After anticholinesterase treatment, the postsynaptic muscle membrane is depolarized by about 5 mV due to nonquantal release of acetylcholine (ACh) from the motor nerve terminal. This can be demonstrated by the hyperpolarization produced by the addition of curare (H-effect). The magnitude of the H-effect was decreased significantly to 3 mV when the nitric oxide (NO) donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP) were applied to the muscle, or when NO production was elevated by adding l -arginine, but not d -arginine, as a substrate. The H-effect was increased to 8,9 mV by inhibition of NO synthase by l -nitroarginine methylester ( l -NAME), or by guanylyl cyclase inhibition by methylene blue and 1H-[1,2,4]oxidiazolo[4,3-a]quinoxalin-1-one (ODQ). ODQ increased the H-effect to 7.3 ± 0.2 mV and diminished the SNP-induced decrease of the H-effect when applied together with SNP. The effects of NO donors and l -arginine were eliminated by adding reduced haemoglobin, an extracellular NO scavenger. The present results, together with earlier evidence for the presence of NO synthase in muscle fibres, indicate that nonquantal release of ACh is modulated by NO production in the postsynaptic cell. [source] Sealing ability of occlusal resin composite restoration using four restorative proceduresEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2008Danuchit Banomyong The purpose of this work was to investigate fluid flow after restoration using four restorative procedures. Micro-gap, internal dye leakage, and micropermeability of bonded interfaces were also investigated. Each tooth was mounted, connected to a fluid flow-measuring device, and an occlusal cavity was prepared. Fluid flow after cavity preparation was recorded as the baseline measurement, and the cavity was restored using one of four restorative procedures: bonding with total-etch (Single Bond 2) or self-etch (Clearfil SE Bond) adhesives without lining; or lining with resin-modified glass-ionomer cement (GIC) (Fuji Lining LC) or conventional GIC (Fuji IX) and then bonding with the total-etch adhesive. Fluid flow was recorded after restoration and at specific time-points up to 6 months thereafter and recorded as a percentage. Micro-gap formation was analyzed using resin replicas and scanning electron microscopy. Internal leakage of 2% methylene blue dye was observed under a light microscope. In micro-permeability testing, fluorescent-dye penetration was investigated using confocal laser microscopy. None of the restorative procedures provided a perfectly sealed restoration. Glass-ionomer lining did not reduce fluid flow after restoration, and micro-gaps were frequently detected. The self-etch adhesive failed to provide a better seal than the total-etch adhesive, and even initial gap formation was rarely observed for the former. Penetration of methylene blue and fluorescent dyes was detected in most restorations. [source] Syntheses, Li Insertion, and Photoactivity of Mesoporous Crystalline TiO2ADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Wenbo Yue Abstract Ordered mesoporous rutile and anatase TiO2 samples are prepared using mesoporous silica SBA-15 as template and freshly synthesized titanium nitrate and titanium chloride solutions as precursors. The rutile material formed from the nitrate solution is monocrystalline and contains minimal amounts of Si with a Si:Ti ratio of 0.031(4), whereas the anatase material formed from the chloride solution comprises nanocrystals and contains a higher content of Si with a Si:Ti ratio of 0.18(3). It is found that control of temperature and selection of Ti-containing precursor play important roles in determining the crystal phase and crystallinity. A possible formation mechanism of porous crystalline TiO2 is suggested. Characterization of these porous materials is performed by XRD, HRTEM, and nitrogen adsorption/desorption. SBA-15-templated mesoporous rutile TiO2 exhibits a higher Li ion insertion capability than KIT-6-templated TiO2 due to its larger surface area. Likewise mesoporous anatase TiO2:SiO2 composite has a better photoactivity than bulk TiO2 or TiO2 -loaded SBA-15 for bleaching methylene blue. [source] Pulmonary embolism in a patient with severe congenital deficiency for factor V during treatment with fresh frozen plasmaHAEMOPHILIA, Issue 3 2005A. García-Noblejas Summary., Thrombosis is a rare complication in patients with congenital clotting factor deficiencies. In most cases, it is related to inherited procoagulant factors, use of central venous catheters or administration of coagulation factor concentrates. There are only a few case reports about thrombotic events during treatment with fresh frozen plasma (FFP). We report the case of a patient with homozygous inherited factor V deficiency, who developed a pulmonary embolism at a time of treatment with methylene blue treated FFP (MBFFP). The patient had only two other factors predisposing to thrombosis and both were acquired: obesity and bed rest. He started anticoagulant treatment with low molecular weight heparin (LMWH) while the deficient factors were replaced with MBFFP. After 8 days of treatment the patient developed a severe respiratory insufficiency. Pulmonary haemorrhage was considered among the differential diagnosis and LMWH was stopped. An inferior vena cava filter was placed without any further thrombotic complications. To our knowledge, there are no reports about patients with clotting factor deficiencies who developed a thrombotic event during treatment with MBFFP. [source] Formation of Oxynitride as the Photocatalytic Enhancing Site in Nitrogen-Doped Titania Nanocatalysts: Comparison to a Commercial Nanopowder,ADVANCED FUNCTIONAL MATERIALS, Issue 1 2005X. Chen Abstract A nitrogen-doped TiO2 nanocolloid has been successfully prepared and its properties compared with the commercially available TiO2 nanomaterial, Degussa P25. Several characterization techniques, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, Raman scattering, and UV-visible reflectance spectra, are combined in order to determine the crystal phase and grain size, shape, degree of nitrogen incorporation, and nature of the resultant oxynitride chemical bonding on the surface and in the bulk. The high relative photocatalytic activity of the nitrogen doped-TiO2 nanocolloid is evaluated through a study of the decomposition of methylene blue under visible light excitation. The ease and degree of substitutional-insertional nitrogen doping is held accountable for the significant increase in photocatalytic activity in the porous nanocolloid versus the nitrided commercial nanopowder. It is suggested that the nitrogen incorporation produces an NO bonding region as evidenced by the resulting XPS spectrum. [source] The effects of methylene blue on ovine post-pneumonectomy pulmonary oedemaACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2010E. V. SUBOROV Background: We recently reported that post-pneumonectomy pulmonary oedema (PPO) occurs after ventilating the remaining lung with excessive tidal volumes. Studies in small animals have indicated that nitric oxide (NO) release increases in hyper-inflated lungs, but confirmatory evidence from larger animals is still lacking. We hypothesized that PPO could be prevented by methylene blue (MB), an inhibitor of NO synthase. Methods: Sheep were subjected to a right-sided pneumonectomy (PE) and randomly assigned to a protectively ventilated group ((PROTV group, n=7) with tidal volumes of 6 ml/kg at 20 inflations/min and a positive end-expiratory pressure (PEEP) of 2 cmH2O, and two groups undergoing ,injurious ventilation' (INJV) with tidal volumes of 12 ml/kg and zero end-expiratory pressure (ZEEP), a control group (INJV group, n=7) and a treatment group subjected to MB 1 h after PE (INJV+MB group, n=7). Haemodynamic variables, lung mechanics, blood gases and plasma nitrites and nitrates (NOx) were determined. Results: PE reduced pulmonary blood volume, extravascular lung water (EVLWI) and quasistatic lung compliance in all groups, in parallel with a rise in peak airway pressure (P<0.05). In the INJV group, pulmonary arterial pressure, EVLWI and pulmonary vascular permeability index increased and arterial oxygenation decreased towards cessation of the experiments. These changes were not antagonized by MB. Plasma NOx increased in all the groups compared with baseline, but with no intergroup difference. Conclusion: MB did not reduce PPO and accumulation of NOx in sheep subjected to ventilation with excessive tidal volumes and ZEEP. [source] | |||||||||||||||||||||||||||||||||||||||||||