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High Affinity (high + affinity)
Kinds of High Affinity Terms modified by High Affinity Selected AbstractsChemInform Abstract: 3-(4-Fluoropiperidin-3-yl)-2-phenylindoles as High Affinity, Selective, and Orally Bioavailable h5-HT2A Receptor Antagonists.CHEMINFORM, Issue 35 2001Michael Rowley Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Molecular imprinted solid-phase extraction of huperzine A from Huperzia SerrataJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2009Guosong Wang Abstract On the basis of the non-covalent interaction between template and monomer, porous molecularly imprinted polymers (MIPs) were synthesized by a thermal-initiated polymerization method using huperzine A as template, acrylamide, or methacrylic acid as function monomer, ethylene glycol dimethacrylate as cross-linking agent. The interaction between template and functional monomers was studied by UV spectrophotometry, which showed a formation of huperzine A-monomer complexes with stoichiometric ratio of 1 : 2 in the pre-polymerized systems. The resultant MIP particles were tested in the equilibrium binding experiment to analyze their adsorption ability to huperzine A, and were characterized by Fourier Transform Infrared (FTIR) study. The recognition properties of MIP were estimated in solid-phase extraction by selecting four compounds (isolated from the Chinese herb Huperzia serrata) as substrates, and were compared with and prior to those of the NIP. High affinity and adsorption of MIP1 which was prepared in chloroform with huperzine A as imprinted molecule, and acrylamide (AM) as functional monomer, made an attractive application of MIP1 in separation processes. In final, using MIP1 solid-phase extraction micro-column, huperzine A was enriched and separated from the real extraction sample of Huperzia serrata. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Tristetraprolin recruits functional mRNA decay complexes to ARE sequencesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2007Heidi H. Hau Abstract AU-rich elements (AREs) in the 3, untranslated region (UTR) of numerous mammalian transcripts function as instability elements that promote rapid mRNA degradation. Tristetraprolin (TTP) is an ARE-binding protein that promotes rapid mRNA decay through mechanisms that are poorly understood. A 31 nucleotide ARE sequences from the TNF-alpha 3, UTR promoted TTP-dependent mRNA decay when it was inserted into the 3, UTR of a beta-globin reporter transcript, indicating that this short sequence was sufficient for TTP function. We used a gel shift assay to identify a TTP-containing complex in cytoplasmic extracts from TTP-transfected HeLa cells that bound specifically to short ARE sequences. This TTP-containing complex also contained the 5,,3, exonuclease Xrn1 and the exosome component PM-scl75 because it was super-shifted with anti-Xrn1 or anti-PMscl75 antibodies. RNA affinity purification verified that these proteins associated specifically with ARE sequences in a TTP-dependent manner. Using a competition binding assay, we found that the TTP-containing complex bound with high affinity to short ARE sequences from GM-CSF, IL-3, TNF-alpha, IL-2, and c-fos, but did not bind to a U-rich sequence from c-myc, a 22 nucleotide poly U sequence or a mutated GM-CSF control sequence. High affinity binding by the TTP-containing complex correlated with TTP-dependent deadenylation and decay of capped, polyadenylated transcripts in a cell-free mRNA decay assay, suggesting that the TTP-containing complex was functional. These data support a model whereby TTP functions to enhance mRNA decay by recruiting components of the cellular mRNA decay machinery to the transcript. J. Cell. Biochem. 100: 1477,1492, 2007. © 2006 Wiley-Liss, Inc. [source] High affinity, high efficiency fibre-reactive dyesCOLORATION TECHNOLOGY, Issue 4 2006Brent Smith A straightforward two-step method for modifying commercial dichlorotriazine-based fibre-reactive dyes prior to their use in the dyeing process can greatly improve affinity and fixation efficiency on cotton, and reduce the salt requirements. The modification used in this study involved prereacting the commercial dyes with either cysteine or cysteamine followed by reaction of the resulting intermediate with cyanuric chloride. Cotton fabric dyed with the modified dyes had technical properties that were essentially equal to those obtained from the unmodified commercial dyes. [source] Reducing bioavailability and phytotoxicity of 2,4-dinitrotoluene by sorption on K-smectite clayENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2007Michael G. Roberts Abstract ,Smectite clays demonstrate high affinities for nitroaromatics that strongly depend on the exchangeable cation. The K-smectites have high affinities for nitroaromatics, but Ca-smectites do not. Here we evaluate the ability of K-smectite to attenuate the bioavailability and hence toxicity of 2,4-dinitrotoluene (2,4-DNT) to the aquatic plant duckweed. In the absence of K-smectite, 2,4-DNT was highly toxic to duckweed. Small amounts of K-smectite reduced toxicity substantially, presumably by reducing 2,4-DNT bioavailability via sorption. [source] Raised water temperature lowers diversity of hyporheic aquatic hyphomycetesFRESHWATER BIOLOGY, Issue 2 2008FELIX BÄRLOCHER Summary 1. The hyporheic zone of a permanent first-order stream was divided into a treatment and a control section using a 1 m deep sheet-metal barrier. During a 4-month pre-treatment period, water temperatures in two transects of the two sections were not different. Upon heating, the water temperature in the treatment transect increased by an average of 4.3 °C over values in the control transect. 2. Eleven bimonthly core samples were taken from a treatment and a control transect, and recovered CPOM was classified as twigs, wood, grass, roots, cedar and deciduous leaves. 3. In both transects, twigs were the most common and deciduous leaves the least common substrates. The number of leaf fragments declined significantly in the heat-treated transect. 4. Diversity and frequencies of occurrence of aquatic hyphomycetes were highest on leaves and lowest on grass and wood. On leaves, their frequency of occurrence was higher in control than in treatment samples. 5. Preliminary results with amplified and cloned 18S DNA sequences revealed many fungal taxa with high affinities to Basidiomycota, particularly to Limnoperdon incarnatum. 6. By itself, higher water temperature due to global warming is likely to lower the availability of substrates for, and therefore the occurrence of, aquatic hyphomycetes. [source] Improved protonation, collision-induced decomposition efficiency and structural assessment for ,red tide' brevetoxins employing nanoelectrospray mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 8 2006Weiqun Wang Abstract Brevetoxins are a group of natural neurotoxins found in blooms of red tide algae. Previous electrospray mass spectrometry (ES-MS) studies show that all brevetoxins have high affinities for sodium ions, and they form abundant sodium adduct ions, [M + Na]+, in ES-MS, even when trace contamination is the only source of sodium ions. Attempts to obtain informative product ions from the collision-induced decomposition (CID) of [M + Na]+ brevetoxin precursor ions resulted only in uninformative sodium ion signals, even under elevated collision energies. In this study, a nano-ES-MS approach was developed wherein ammonium fluoride was used to form cationic [M + NH4]+ adducts of brevetoxin-2 and brevetoxin-3; a significant increase in the abundance of protonated brevetoxin molecules [M + H]+ also resulted, whereas the abundance of sodium adducts of brevetoxins [M + Na]+ was observed to decrease. Under CID, both [M + NH4]+ and [M + H]+ gave similar, abundant product ions and thus underwent the same types of fragmentation. This indicated that ammonium ions initially attached to brevetoxins forming [M + NH4]+ easily lose neutral ammonia in a first step in the gas phase, leaving protonated brevetoxin [M + H]+ to readily undergo further fragmentation under CID. Copyright © 2006 John Wiley & Sons, Ltd. [source] Decreased density of muscarinic receptors in the superior temporal gyrusin schizophreniaJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2005Chao Deng Abstract Recent studies have indicated that muscarinic receptors are involved in the pathophysiology in schizophrenia, particularly in cognitive deficits. The superior temporal gyrus (STG) is an area that has also been strongly implicated in the pathophysiology of schizophrenia. Therefore, in this study, we investigated the binding density of two muscarinic antagonists, [3H]pirenzepine and [3H]AF-DX384, in the STG of schizophrenia patients compared with controls. A significant decrease (44% in the superficial layers and 48% in the deep layers, P < 0.01) in binding density of [3H]pirenzepine was observed in schizophrenia patients, which suggested a reduction of muscarinic M1 and M4 receptor densities in the STG of schizophrenia patients. A tendency toward decreased [3H]AF-DX384 binding density (34%, P = 0.09) was also observed in schizophrenia patients compared with controls. Because of the positive correlation between [3H]pirenzepine and [3H]AF-DX384 binding, and, insofar as both ligands have high affinities for the M4 receptor, the involvement of M4 receptor alteration is also suggested in the STG in schizophrenia. These results suggest that changes of the muscarinic receptors M1 and M4 might contribute to the STG pathology in schizophrenia. © 2005 Wiley-Liss, Inc. [source] Introduction of lipidization,cationization motifs affords systemically bioavailable neuropeptide Y and neurotensin analogs with anticonvulsant activitiesJOURNAL OF PEPTIDE SCIENCE, Issue 9 2010Brad R. Green Abstract The neuropeptides galanin (GAL), neuropeptide Y (NPY) or neurotensin (NT) exhibit anticonvulsant activities mediated by their respective receptors in the brain. To transform these peptides into potential neurotherapeutics, their systemic bioavailability and metabolic stability must be improved. Our recent studies with GAL analogs suggested that an introduction of lipoamino acids in the context of oligo-Lys residues (lipidization,cationization motif) significantly increases their penetration into the brain, yielding potent antiepileptic compounds. Here, we describe an extension of this strategy to NPY and NT. Rationally designed analogs of NPY and NT containing the lipidization,cationization motif were chemically synthesized and their physicochemical and pharmacological properties were characterized. The analogs NPY-BBB2 and NT-BBB1 exhibited increased serum stability, possessed log D > 1.1, retained high affinities toward their native receptors and produced potent antiseizure activities in animal models of epilepsy following intraperitoneal administration. Our results suggest that the combination of lipidization and cationization may be an effective strategy for improving systemic bioavailability and metabolic stability of various neuroactive peptides. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. [source] Small potent ligands to the insulin-regulated aminopeptidase (IRAP)/AT4 receptorJOURNAL OF PEPTIDE SCIENCE, Issue 7 2007Andreas Axén Abstract Angiotensin IV analogs encompassing aromatic scaffolds replacing parts of the backbone of angiotensin IV have been synthesized and evaluated in biological assays. Several of the ligands displayed high affinities to the insulin-regulated aminopeptidase (IRAP)/AT4 receptor. Displacement of the C -terminal of angiotensin IV with an o -substituted aryl acetic acid derivative delivered the ligand 4, which exhibited the highest binding affinity (Ki = 1.9 nM). The high affinity of this ligand provides support to the hypothesis that angiotensin IV adopts a ,-turn in the C -terminal of its bioactive conformation. Ligand (4) inhibits both human IRAP and aminopeptidase N-activity and induces proliferation of adult neural stem cells at low concentrations. Furthermore, ligand 4 is degraded considerably more slowly in membrane preparations than angiotensin IV. Hence, it might constitute a suitable research tool for biological studies of the (IRAP)/AT4 receptor. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] TEM-1 ,-lactamase as a scaffold for protein recognition and assayPROTEIN SCIENCE, Issue 6 2002Daniel Legendre Abstract A large number of different proteins or protein domains have been investigated as possible scaffolds to engineer antibody-like molecules. We have previously shown that the TEM-1 ,-lactamase can accommodate insertions of random sequences in two loops surrounding its active site without compromising its activity. From the libraries that were generated, active enzymes binding with high affinities to monoclonal antibodies raised against prostate-specific antigen, a protein unrelated to ,-lactamase, could be isolated. Antibody binding was shown to affect markedly the enzyme activity. As a consequence, these enzymes have the potential to be used as signaling molecules in direct or competitive homogeneous immunoassay. Preliminary results showed that ,-lactamase clones binding to streptavidin could also be isolated, indicating that some enzymes in the libraries have the ability to recognize proteins other than antibodies. In this paper, we show that, in addition to ,-lactamases binding to streptavidin, ,-lactamase clones binding to horse spleen ferritin and ,-galactosidase could be isolated. Affinity maturation of a clone binding to ferritin allowed obtaining ,-lactamases with affinities comprised between 10 and 20 nM (Kd) for the protein. Contrary to what was observed for ,-lactamases issued from selections on antibodies, enzyme complexation induced only a modest effect on enzyme activity, in the three cases studied. This kind of enzyme could prove useful in replacement of enzyme-conjugated antibodies in enzyme-linked immunosorbant assays (ELISA) or in other applications that use antibodies conjugated to an enzyme. [source] Selection and mass spectrometry characterization of peptides targeting semiconductor surfacesBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009Elias Estephan Abstract We report on elaboration of 12-mer peptides that reveal specific recognition for the following semiconductor (SC) surfaces: GaAs(100), InAs(100), GaN(0001), ZnSe(100), ZnTe(100), GaAs(111)A, GaSb(100), CdSe(100). A M13 bacteriophage library was used to screen 109 different 12-mer peptides against these substrates to finally isolate, in maximum six amplification cycles, peptides that bind to the target surfaces. The specific peptides for the InAs and ZnSe surfaces were obtained. Contrary, for the other SC surfaces several peptides with high affinities have been isolated. Aiming for a better specificity, when the phage display has been conducted through six cycles, the screening procedure got dominated by a phage present in the M13 bacteriophage library and the SVSVGMKPSPRP peptide has been selected for different SCs. The high amplification potential of this phage has been observed previously with different targets. Thus, precaution should be undertaken in defining adhesion peptides with the phage display technique and real affinity of the obtained biolinkers should be studied with other methods. We employed mass spectrometry (MALDI-TOF/TOF) to demonstrate the preferential attachment (or not) of the SVSVGMKPSPRP peptide to the different SC surfaces. This allows us to define a realistic selection of the expressed peptides presenting affinity for the studied eight SC surfaces. We demonstrate that with increasing the dielectric constants of the employed solvents, adhesion of the SVSVGMKPSPRP peptide onto GaN(0001) is hindered. Biotechnol. Bioeng. 2009; 104: 1121,1131. © 2009 Wiley Periodicals, Inc. [source] Cyclic Control of the Surface Properties of a Monolayer-Functionalized Electrode by the Electrochemical Generation of Hg NanoclustersCHEMISTRY - A EUROPEAN JOURNAL, Issue 33 2006Michael Riskin Abstract Hg2+ ions are bound to a 1,4-benzenedimethanethiol (BDMT) monolayer assembled on a Au electrode. Electrochemical reduction of the Hg2+,BDMT monolayer to Hg+,BDMT (at E°=0.48 V) and subsequently to Hg0,BDMT (at E°=0.2 V) proceeds with electron-transfer rate constants of 8 and 11 s,1, respectively. The Hg0 atoms cluster into aggregates that exhibit dimensions of 30 nm to 2 ,m, within a time interval of minutes. Electrochemical oxidation of the nanoclusters to Hg+ and further oxidation to Hg2+ ions proceeds with electron-transfer rate constants corresponding to 9 and 43 s,1, respectively, and the redistribution of Hg2+ on the thiolated monolayer occurs within approximately 15 s. The reduction of the Hg2+ ions to the Hg0 nanoclusters and their reverse electrochemical oxidation proceed without the dissolution of mercury species to the electrolyte, implying high affinities of Hg2+, Hg+, and Hg0 to the thiolated monolayer. The electrochemical transformation of the Hg2+ -thiolated monolayer to the Hg0 -nanocluster-functionalized monolayer is characterized by electrochemical means, surface plasmon resonance (SPR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact-angle measurements. The Hg0 -nanocluster-modified surface reveals enhanced hydrophobicity (contact angle 76°) as compared to the Hg2+ -thiolated monolayer (contact angle 57°). The hydrophobic properties of the Hg0 -nanocluster-modified electrode are further supported by force measurements employing a hydrophobically modified AFM tip. [source] Evaluation of tumor affinity of mono-[123I]iodohypericin and mono-[123I]iodoprotohypericin in a mouse model with a RIF-1 tumorCONTRAST MEDIA & MOLECULAR IMAGING, Issue 3 2007Humphrey Fonge Abstract In this study we have compared the tumour-seeking properties of mono-[123I]iodoprotohypericin and mono-[123I]iodohypericin in C3H mice with a subcutaneous radiation-induced fibrosarcoma-1 tumor. After intravenous injection, both tracers were rapidly cleared from all organs and were retained by the tumors. There was no significant difference in tumor uptake of the two tracers at all studied time points (p,>,0.05). To study the plausible mechanism of hypericin and mono-iodohypericin uptake in tumor, their plasma binding profile was investigated. Both agents show high affinity for low-density lipoproteins and to a lesser extent high-density lipoproteins and other heavy proteins. Mono-[123I]iodohypericin appears to be more promising as a tumor diagnostic agent, given its faster clearance from all organs. Copyright © 2007 John Wiley & Sons, Ltd. [source] A study of primary nucleation of calcium oxalate monohydrate: II.CRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2004Effect of urinary species Abstract Kidney stones consist of various organic and inorganic compounds. Calcium oxalate monohydrate (COM) is the main inorganic constituent of kidney stones. However, the mechanisms for the formation of calcium oxalate kidney stones are not well understood. In this regard, there are several hypotheses including nucleation, crystal growth and/or aggregation of formed COM crystals. The effect of some urinary species such as oxalate, calcium, citrate, and protein on nucleation and crystallization characteristics of COM is determined by measuring the weight of formed crystals and their size distributions under different chemical conditions, which simulate the urinary environment. Statistical experimental designs are used to determine the interaction effects among various factors. The data clearly show that oxalate and calcium promote nucleation and crystallization of COM. This is attributed to formation of a thermodynamically stable calcium oxalate monohydrate resulting from supersaturation. Citrate, however, inhibits nucleation and further crystal growth. These results are explained on the basis of the high affinity of citrate to combine with calcium to form soluble calcium citrate complexes. Thus, citrate competes with oxalate ion for binding to calcium cations. These conditions decrease the amount of free calcium ions available to form calcium oxalate crystals. In case of protein (mucin), however, the results suggest that no significant effect could be measured of mucin on nucleation and crystal growth. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Ca2+ -dependent in vitro contractility of a precipitate isolated from an extract of the heliozoon Actinophrys solCYTOSKELETON, Issue 2 2006Mikihiko Arikawa Abstract Contraction of axopodia in actinophrid heliozoons (protozoa) is induced by a unique contractile structure, the "contractile tubules structure (CTS)". We have previously shown that a cell homogenate of the heliozoon Actinophrys sol yields a precipitate on addition of Ca2+ that is mainly composed of filamentous structures morphologically identical to the CTS. In this study, to further characterize the nature of the CTS in vitro, biochemical and physiological properties of the precipitate were examined. SDS-PAGE analysis showed that the Ca2+ -induced precipitate was composed of many proteins, and that no proteins in the precipitate showed any detectable changes in electrophoretic mobility on addition of Ca2+. Addition of extraneous proteins such as bovine serum albumin to the cell homogenate resulted in cosedimentation of the proteins with the Ca2+ -induced precipitate, suggesting that the CTS has a high affinity for other proteins that are not related to precipitate formation. Appearance and disappearance of the precipitate were repeatedly induced by alternating addition of Ca2+ and EGTA, and its protein composition remained unchanged even after repeated cycles. When adhered to a glass surface, the precipitate showed Ca2+ -dependent contractility with a threshold of 10,100 nM, and this contractility was not inhibited by colchicine or cytochalasin B. The precipitate repeatedly contracted and relaxed with successive addition and removal of Ca2+, indicating that the contraction was controlled by Ca2+ alone with no need for any other energy supply. From our characterization of the precipitate, we concluded that its Ca2+ -dependent formation and contraction are associated with the unique contractile organelle, the "contractile tubules structure". Cell Motil. Cytoskeleton 2006. © 2005 Wiley-Liss, Inc. [source] HOXA13 directly regulates EphA6 and EphA7 expression in the genital tubercle vascular endotheliaDEVELOPMENTAL DYNAMICS, Issue 4 2007Carley A. Shaut Abstract Hypospadias, a common defect affecting the growth and closure of the external genitalia, is often accompanied by gross enlargements of the genital tubercle (GT) vasculature. Because Hoxa13 homozygous mutant mice also exhibit hypospadias and GT vessel expansion, we examined whether genes playing a role in angiogenesis exhibit reduced expression in the GT. From this analysis, reductions in EphA6 and EphA7 were detected. Characterization of EphA6 and EphA7 expression in the GT confirmed colocalization with HOXA13 in the GT vascular endothelia. Analysis of the EphA6 and EphA7 promoter regions revealed a series of highly conserved cis -regulatory elements bound by HOXA13 with high affinity. GT chromatin immunoprecipitation confirmed that HOXA13 binds these gene-regulatory elements in vivo. In vitro, HOXA13 activates gene expression through the EphA6 and EphA7 gene-regulatory elements. Together these findings indicate that HOXA13 directly regulates EphA6 and EphA7 in the developing GT and identifies the GT vascular endothelia as a novel site for HOXA13-dependent expression of EphA6 and EphA7. Developmental Dynamics 236:951,960, 2007. © 2007 Wiley-Liss, Inc. [source] Developments in the prediction of type 1 diabetes mellitus, with special reference to insulin autoantibodiesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 5 2005Bernd Franke Abstract The prodromal phase of type 1 diabetes is characterised by the appearance of multiple islet-cell related autoantibodies (Aab). The major target antigens are islet-cell antigen, glutamic acid decarboxylase (GAD), protein-tyrosine phosphatase-2 (IA-2) and insulin. Insulin autoantibodies (IAA), in contrast to the other autoimmune markers, are the only ,-cell specific antibodies. There is general consensus that the presence of multiple Aab (, 3) is associated with a high risk of developing diabetes, where the presence of a single islet-cell-related Aab has usually a low predictive value. The most commonly used assay format for the detection of Aab to GAD, IA-2 and insulin is the fluid-phase radiobinding assay. The RBA does not identify or measure Aab, but merely detects its presence. However, on the basis of molecular studies, disease-specific constructs of GAD and IA-2 have been employed leading to somewhat improved sensitivity and specificity of the RBA. Serological studies have shown epitope restriction of IAA that can differentiate diabetes-related from unrelated IAA, but current assays do not distinguish between disease-predictive and non-predictive IAA or between IAA and insulin antibodies (IA). More recently, phage display technology has been successful in identifying disease-specific anti-idiotopes of insulin. In addition, phage display has facilitated the in vitro production of antibodies with high affinity. Identification of disease-specific anti-idiotopes of insulin should enable the production of a high affinity reagent against the same anti-idiotope. Such a development would form the basis of a disease-specific radioimmunoassay able to identify and measure particular idiotypes, rather than merely detect and titrate IAA. Copyright © 2005 John Wiley & Sons, Ltd. [source] Cytotoxicity of doxorubicin-loaded Con A-liposomesDRUG DEVELOPMENT RESEARCH, Issue 5 2006Hercília Maria Lins Rolim Santos Abstract The present study investigated the potential of Concanavalin A lectin (Con A) conjugated to liposomes (Con A-liposomes) for targeting doxorubicin (DOX) to cells. The physicochemical properties and the cytotoxicity of DOX-loaded Con A-liposomes were evaluated. DOX-loaded Con A-liposomes were prepared by incubation of DOX-loaded liposomes with a Con A-SATA derivative. Lectin biological activity was monitored before and after conjugation by a hemagglutinating assay. The cytotoxicity of DOX-loaded Con A-liposomes was evaluated in terms of the inhibition of NCI-H299 and HEp-2 cell proliferation using the MTT method. The affinity of lectinized liposomes with these cells was thus assessed by evaluating the cytotoxic effect of the DOX released into cells. Stable DOX-loaded Con A-liposomes were obtained and their high affinity for cells was corroborated. The encapsulation of DOX into Con A-liposomes produced an inhibition of roughly 70% of Hep-2 cell proliferation and 50% of cell inhibition was verified on HCI-H292. DOX in solution was able to inhibit only 20% of cell proliferation for both cell lines. Unloaded Con A-liposomes were not cytotoxic. The encapsulation of DOX into Con A-liposomes improves drug penetration into cells, thereby enhancing its cytotoxicity, especially in Hep-2 cells. Drug Dev. Res. 67:430,437, 2006. © 2006 Wiley-Liss, Inc. [source] In vitro and in vivo characterization of TC-1827, a novel brain ,4,2 nicotinic receptor agonist with pro-cognitive activityDRUG DEVELOPMENT RESEARCH, Issue 1 2004Georg Andrees Bohme Abstract Nicotine activates specific receptors that are cation-permeable ionic channels located in the central and autonomous nervous systems, as well as at the neuromuscular junction. Administration of nicotine to animals and humans has been shown to enhance cognitive processes. However, side effects linked to the activation of peripheral nicotinic receptors limit the usefulness of nicotine for the treatment of cognitive disorders such as Alzheimer's disease (AD) or mild cognitive impairments (MCI). The synthesis and properties of TC-1827, a novel metanicotine derivative that activates brain ,4,2 nicotinic receptors is described. TC-1827 has high affinity for nicotine-labeled receptors in the cortex (Ki=34 nM), full-agonist intrinsic activity in ,4,2 -mediated neurotransmitter release studies in synaptosomes, and has no functional activity at nicotinic receptors in ganglionic or muscular cell lines. The compound enhances long-term potentiation in hippocampal slices, a form of synaptic plasticity thought to be involved in information storage at the cellular level. In vivo studies demonstrate that TC-1827 dose-dependently occupies thalamic nicotinic receptors labeled with [3H]-cytisine, increases cortical extracellular acetylcholine levels following oral administration, and enhances cognitive performance in rat and mice behavioral procedures of learning and memory. Pharmacokinetic studies in mice, rats, and monkeys indicated that TC-1827 has good oral absorption with a first pass effect resulting in bioavailabilities of 13,65% across dose/species. Cardiovascular safety studies indicate good cardiovascular tolerability for this compound. The present data demonstrate that TC-1827 is a selective and potent activator of brain ,4,2 nicotinic receptors and is a prototypical member of a new class of compounds with potential utility in the symptomatic treatment of cognitive disorders including AD and MCI. Drug Dev. Res. 62:26,40, 2004. © 2004 Wiley-Liss, Inc. [source] Voltammetric Studies of the Interactions Between Ferrocene-Labeled Glutathione and Proteins in Solution or Immobilized onto SurfaceELECTROANALYSIS, Issue 16 2009Yong Peng Abstract Glutathione (GSH) tagged with a ferrocene (Fc) label at its C-terminal was synthesized via coupling ferrocenyl amine to glutathione using o -(benzotriazol-1-yl)- N,N,N,,N, -tetramethyluronium (HBTU)/1-hydroxybenzotrizole (HOBt). The presence of Fc yielded well defined voltammetric signals, rendering the Fc-tagged GSH (GSH-Fc) suitable for electrochemical studies of GSH binding to other biological species. The interaction of GSH-Fc with bovine serum albumin (BSA) was investigated, and a binding ratio of 1.41±0.06 (GSH-Fc/BSA) and an affinity constant Ka of 6.53±2.01×106,M,1 were determined. These results compare well with those measured by fluorescence using untagged GSH, suggesting that the attachment of Fc to GSH does not significantly perturb the GSH structure and binding behavior. By contrasting the binding behavior to several compounds that are known to conjugate to different domains of BSA, the voltammetric study confirmed that GSH-Fc binds at subdomain IIA of BSA with high affinity. The versatility of GSH-Fc for studying GSH binding to surface-confined proteins was also demonstrated with the GSH binding to electroinactive Zn-metallothionein (Zn7 -MT) through hydrogen binding at the region between the Zn7 -MT , and , domains. [source] Dendritic Silver/Silicon Dioxide Nanocomposite Modified Electrodes for Electrochemical Sensing of Hydrogen PeroxideELECTROANALYSIS, Issue 17 2008Peixi Yuan Abstract A novel biosensor for hydrogen peroxide was prepared by immobilizing horseradish peroxidase (HPR) on newly synthesized dendritic silver/silicon dioxide nanocomposites, which were coated on a glassy carbon electrode. The modified electrode was characterized with XPS, SEM, and electrochemical methods. This biosensor showed a very fast amperometric response to hydrogen peroxide with a linear range from 0.7 to 120,,M, a limit of detection of 0.05,,M and a sensitivity of 1.02,mA mM,1 cm,2. The Michaelis-Menten constant of the immobilized HRP was estimated to be 0.21,mM, indicating a high affinity of the HRP to H2O2 without loss of enzymatic activity. The preparation of the proposed biosensor was convenient, and it showed high sensitivity and good stability. [source] Adsorptive Stripping Voltammetric Detection of Single-Stranded DNA at Electrochemically Modified Glassy Carbon ElectrodeELECTROANALYSIS, Issue 23 2002Huai-Sheng Wang Abstract Electrochemically modified glassy carbon electrode (GCE) was used to study the electrochemical oxidation and detection of denatured single-stranded (ss) DNA by means of adsorptive stripping voltammetry. The modification of GCE, by electrochemical oxidation at +1.75,V (vs.SCE) for 10,min and cyclic sweep between +0.3,V and ,1.3,V for 20,cycles in pH,5.0 phosphate buffer, results in 100-fold improvement in sensitivity for ssDNA detection. We speculated that the modified GCE has a high affinity to single-stranded DNA through hydrogen bond (specific static adsorption). Single-stranded DNA can accumulate at the GCE surface at open circuit and produce a well-defined oxidation peak corresponding to the guanine residues at about +0.80,V in pH,5.0 phosphate buffer, while the native DNA gives no signal under the same condition. The peak currents are proportional to the ssDNA concentration in the range of 0,18.0,,g,mL,1. The detection limit of denatured ssDNA is ca. 0.2,,g mL,1 when the accumulation time is 8,min at open circuit. The accumulation mechanism of ssDNA on the modified GCE was discussed. [source] High-sensitive determination of human ,-thrombin by its 29-mer aptamer in affinity probe capillary electrophoresisELECTROPHORESIS, Issue 12 2008Yilin Li Abstract ACE technique provides an effective tool for the separation and identification of disease-related biomarkers in clinical analysis. In recent years, a couple of synthetic DNA or RNA oligonucleotides, known as aptamers, rival the specificity and affinity for targets to antibodies and are employed as one kind of powerful affinity probe in ACE. In this work, based on high affinity between antithrombin aptamer and thrombin (their dissociation constant is 0.5,nM), a carboxyfluorescein-labeled 29-nucleotide (nt) aptamer (F29-mer) was used and an aptamer-based affinity probe CE (aptamer-based APCE) method was successfully established for high-sensitive detection and quantitative analysis of thrombin. Experimental conditions including incubation temperature and time, buffer composition, and concentration of cations were investigated and optimized. Under the optimized condition, the linear range was from 0 to 400,nM and the LOD was 2,nM (74,ng/mL, S/N,=,3), i.e., 40,amol, both in running buffer and in 5% v/v human serum. This LOD is the lowest one than those achieved by the previous APCE methods but based on a 15-mer aptamer. This approach offers a promising method for the rapid, selective, and sensitive detection of thrombin in practical utility. Further binding experiments using one carboxyfluorescein-labeled aptamer and the other nonlabeled aptamer or vice versa were carried out to deduce the formation of ternary complex when these two aptamers coexisted in the free solution with thrombin. [source] CE with electrochemical detection for investigation of label-free recognition of amino acid amides by guanine-rich DNA aptamersELECTROPHORESIS, Issue 17 2007Tao Li Abstract In this work, we report a simple and effective investigation into adaptive interactions between guanine-rich DNA aptamers and amino acid amides by CE with electrochemical (EC) detection. Argininamide (Arm) and tyrosinamide (Tym) were chosen as model molecules. On a copper electrode, Arm generated a good EC signal in 60 mM NaOH at 0.7 V (vs Ag/AgCl), while Tym was detected well on a platinum electrode at 1.3 V in 20 mM phosphate of pH 7.0. Based on their EC properties, the ligands themselves were used as indicators for the adaptive interactions investigated by CE-EC, making any step of labeling and/or modification of aptamers with indicators exempted. Hydrophilic ionic liquid was used as an additive in running buffer of CE to improve the sensitivity of Arm detection, whereas the additive was not used for Tym detection due to its negative effect. Two guanine-rich DNA aptamers were used for molecular recognition of Arm and Tym. When the aptamers were incubated with ligands, they bound the model molecules with high affinity and specificity, reflected by obvious decreases in the signals of ligands but no changes in those of the control molecules. However, the ligands were hardly affected by the control ssDNAs after incubation. The results revealed the specific recognition of Arm and Tym by the aptamers. The mechanisms for binding model molecules by aptamers were discussed. Not as expected, these aptamers were not to form the G-quartets, which were generally responsible for binding the ligands when the guanine-rich aptamers were used. [source] Isolation and characterization of naphthalene-degrading bacteria from sediments of Cadiz area (SW Spain)ENVIRONMENTAL TOXICOLOGY, Issue 5 2008D. Nair Abstract Petroleum hydrocarbon contamination of harbor sediments from shipping activity, fuel oil spills, and runoffs are becoming a great concern because of the toxicity and recalcitrance of many of the fuel components. Polycyclic aromatic hydrocarbons (PAHs) are of most concern due to their toxicity, low volatility, resistance to degradation, and high affinity for sediments. Microorganisms, especially bacteria, play an important role in the biodegradation of these hydrocarbons. The objective of the present study was to characterize and isolate PAH-(naphthalene) degrading bacteria in the coastal sediments of Cadiz (SW Spain), since this area is mostly polluted by PAH occurrence. A total of 16 naphthalene-utilizing bacteria were isolated from these sites. Introduction of bacteria isolated from contaminated sediments into mineral medium contributed to the increased rate of hydrocarbon utilization. The bacterial isolates obtained from these sites are very potent in utilizing naphthalene and crude oil. It would be interesting to assess if the selected naphthalene-degrading isolates may degrade other compounds of similar structure. Hence these isolates could be very helpful in bioremediating the PAH-contaminated sites. Further pursue on this work might represent eco-friendly solution for oil contamination on sea surface and coastal area. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Histopathological alterations in the edible snail, Babylonia areolata (spotted babylon), in acute and subchronic cadmium poisoningENVIRONMENTAL TOXICOLOGY, Issue 2 2005P. Tanhan Abstract Histopathological alterations in 6- to 8-month-old juvenile spotted babylon, Babylonia areolata, from acute and subchronic cadmium exposure were studied by light microscopy. The 96-h LC50 value of cadmium for B. areolata was found to be 3.35 mg/L, and the maximum acceptable toxicant concentration (MATC) was 1.6 mg/L. Snails were exposed to 3.35 and 0.08 mg/L (5% of MATC) of cadmium for 96 h and 90 days, respectively. After exposure the gill, the organs of the digestive system (proboscis, esophagus, stomach, digestive gland, and rectum), and the foot were analyzed for cadmium accumulation. The results showed that most digestive organs had a high affinity for cadmium. The main target organ was the stomach, which could accumulate on average 1192.18 ,g/g dry weight of cadmium. Cadmium was shown to accumulate to a lesser extent in the digestive gland, gill, rectum, esophagus, proboscis, and foot. Histopathological alterations were observed in the gill and digestive organs (proboscis, esophagus, stomach, and rectum). The study showed that the stomach and gill were the primary target organs of both acute and subchronic exposure. Gill alterations included increased size of mucous vacuoles, reduced length of cilia, dilation and pyknosis of nuclei, thickening of basal lamina, and accumulation of hemocytes. The epithelial lining of the digestive tract showed similar alterations such as increased size of mucous vacuoles, reduced length of cilia, and dilation of nuclei. In addition, fragmentation of the muscle sheath was observed. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 142,149, 2005. [source] Activation of the aryl hydrocarbon receptor reveals distinct requirements for IL-22 and IL-17 production by human T helper cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2010Jean-Marie Ramirez Abstract Ligands of the aryl hydrocarbon receptor (AHR), a transcription factor mediating the effects of dioxin, favor Th17 differentiation and exacerbate autoimmunity in mice. We investigated how AHR ligands affected human T-cell polarization. We found that the high affinity and stable AHR-ligand dioxin as well as the natural AHR-ligand 6-formylinolo[3,2-b] carbazole induced the downstream AHR-target cytochrome P450A1, and without affecting IFN-,, they enhanced IL-22 while simultaneously decreasing IL-17A production by CD4+ T cells. The specific AHR-inhibitor CH-223191 abolished these effects. Furthermore, blockade of IL-23 and IL-1, important for Th17 expansion, profoundly decreased IL-17A but not IL-22 production. AHR agonists reduced the expression of the Th17 master transcription factor retinoic acid-related orphan receptor C (RORC), without affecting T-bet, GATA-3 and Foxp3. They also decreased the expression of the IL-23 receptor. Importantly, AHR-ligation did not only decrease the number of Th17 cells but also primed naïve CD4+ T cells to produce IL-22 without IL-17 and IFN-,. Furthermore, IL-22 single producers did not express CD161, which distinguished them from the CD161+ Th17 cells. Hence, our data provide compelling evidence that AHR activation participates in shaping human CD4+ T-cell polarization favoring the emergence of a distinct subset of IL-22-producing cells that are independent from the Th17 lineage. [source] CCR3 functional responses are regulated by both CXCR3 and its ligands CXCL9, CXCL10 and CXCL11EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2003Georgina Xanthou Abstract The chemokine receptor CXCR3 is predominantly expressed on T lymphocytes, and its agonists CXCL9, CXCL10 and CXCL11 are IFN-,-inducible chemokines that promote Th1 responses. In contrast, the CCR3 agonists CCL11, CCL24 and CCL26 are involved in the recruitment of cells such as eosinophils and basophils during Th2 responses. Here, we report that although CCL11, CCL24 and CCL26 are neither agonists nor antagonists of CXCR3, CCL11 binds with high affinity to CXCR3. This suggests that, in vivo, CXCR3 may act as a decoy receptor, sequestering locally produced CCL11. We alsodemonstrate that the CXCR3 ligands inhibit CCR3-mediated functional responses of both human eosinophils and CCR3 transfectants induced by all three eotaxins, with CXCL11 being the most efficacious antagonist. The examination of CCR3,CCR1 chimeric constructs revealed that CCL11 and CXCL11 share overlapping binding sites contained within the CCR3 extracellular loops, a region that was previously shown to be essential for effective receptor-activation. Hence, eosinophil responses mediated by chemokines acting at CCR3 may be regulated by two distinct mechanisms: the antagonistic effects of CXCR3 ligands and the sequestration of CCL11 by CXCR3-expressing cells. Such interplay may serve to finely tune inflammatory responses in vivo. [source] Pergolide mesylate can improve sexual dysfunction in patients with Parkinson's disease: the results of an open, prospective, 6-month follow-upEUROPEAN JOURNAL OF NEUROLOGY, Issue 7 2004M. Pohanka One of the most disabling problems in males suffering from advanced Parkinson's disease (PD) is complex sexual dysfunction. The effect of dopamine replacement or dopaminergic stimulation on sexual dysfunction has been recently examined and described in patients treated by L-DOPA or apomorphine. Pergolide mesylate is another dopamine agonist with a known high affinity to hD(2S) subtype and a lower affinity to hD(2L) subtype of D2 dopaminergic receptors. It has been repeatedly shown to be a highly effective treatment of the complicated and advanced stages of PD. The current study has been designed to assess its efficacy in the treatment of sexual dysfunction, which frequently accompanies the complicated stage of PD in males. Fourteen male patients suffering from PD, each of whom had been treated with L-DOPA, and in whom additional treatment with peroral dopaminergic agonist (DA) was needed, were followed for a 6-month period. Pergolide mesylate (Permax) was given to each patient, and titrated to a total daily dose of 3 mg. All of the patients were taking L-DOPA. The assessments performed before the start of pergolide treatment consisted of a neurological examination, including Unified Parkinson's Disease Rating Scale (UPDRS) III and IV subscales scoring, Mini Mental State Examination (MMSE) scoring, the neuropsychological examination including Zung scale scoring to exclude depression, biochemical and haematological examinations including the examination of prolactine serum levels; and a sexological examination during which the patients filled-in the International Index of Erectile Function (IIEF) questionnaire. These examinations were repeated during the control assessments at months 1, 3 and 6. To compare the examination results, anova, Friedmann's anova (non-parametric) and Tukey post hoc tests were used. There were statistically significant differences between the values of UPDRS III motor subscale, UPDRS IV (complications of therapy) subscale and all subscales of IIEF when months 0 and 1 were compared with the results obtained at months 3 and 6. The differences between months 0 and 1 and months 3 and 6 (in these items) were virtually insignificant. In conclusion, pergolide substantially improved sexual function in the younger male patients who were still interested in sexual activities. In such cases, the introduction of pergolide might be a better choice than treatment with sildenafile, which usually meets several contraindications in common PD male population. [source] | ||||||||||||||||||||||||||||||||||||||||