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Sample records for alpha selectively sensitizes

  1. In Vitro Selection of Single-Stranded DNA Molecular Recognition Elements against S. aureus Alpha Toxin and Sensitive Detection in Human Serum

    PubMed Central

    Hong, Ka L.; Battistella, Luisa; Salva, Alysia D.; Williams, Ryan M.; Sooter, Letha J.

    2015-01-01

    Alpha toxin is one of the major virulence factors secreted by Staphylococcus aureus, a bacterium that is responsible for a wide variety of infections in both community and hospital settings. Due to the prevalence of S. aureus related infections and the emergence of methicillin-resistant S. aureus, rapid and accurate diagnosis of S. aureus infections is crucial in benefiting patient health outcomes. In this study, a rigorous Systematic Evolution of Ligands by Exponential Enrichment (SELEX) variant previously developed by our laboratory was utilized to select a single-stranded DNA molecular recognition element (MRE) targeting alpha toxin with high affinity and specificity. At the end of the 12-round selection, the selected MRE had an equilibrium dissociation constant (Kd) of 93.7 ± 7.0 nM. Additionally, a modified sandwich enzyme-linked immunosorbent assay (ELISA) was developed by using the selected ssDNA MRE as the toxin-capturing element and a sensitive detection of 200 nM alpha toxin in undiluted human serum samples was achieved. PMID:25633102

  2. 3-[2,4-Dimethoxybenzylidene]anabaseine (DMXB) selectively activates rat alpha7 receptors and improves memory-related behaviors in a mecamylamine-sensitive manner.

    PubMed

    Meyer, E M; Tay, E T; Papke, R L; Meyers, C; Huang, G L; de Fiebre, C M

    1997-09-12

    The alpha7 nicotinic receptor agonist 3-[2,4-dimethoxybenzylidene]anabaseine (DMXB; GTS-21) was investigated for its ability to: (1) activate a variety of nicotinic receptor subtypes in Xenopus oocytes; (2) improve passive avoidance and spatial Morris water task performances in mecamylamine-sensitive manners in bilaterally nucleus basalis lesioned rats; and (3) elevate high-affinity [3H]acetylcholine (ACh) and high-affinity alpha-[125I]bungarotoxin binding in rat neocortex following 2 weeks of daily injections. DMXB (100 microM) activated alpha7 homo-oligomeric receptors, without significant activity at alpha2-, alpha3- and alpha4-containing subtypes. Mecamylamine blocked rat alpha7 receptors weakly if co-administered with agonist, but much more potently when pre-applied. Bilateral ibotenic acid lesions of the nucleus basalis interfered with passive avoidance and spatial memory-related behaviors. DMXB (0.5 mg/kg, i.p.) improved passive avoidance behavior in lesioned animals in a mecamylamine-sensitive manner. DMXB (0.5 mg/kg 15 min before each session) also improved performance in the training and probe components of the Morris water task. DMXB-induced improvement in the probe component but not the training phase was mecamylamine-sensitive. [3H]ACh binding was elevated after 14 days of daily i.p. injections with 0.2 mg/kg nicotine but not after 1 mg/kg DMXB. Neither drug elevated high-affinity alpha-[125I]bungarorotoxin binding over this interval.

  3. Alpha-particle sensitive test SRAMs

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.

    1990-01-01

    A bench-level test is being developed to evaluate memory-cell upsets in a test SRAM designed with a cell offset voltage. This offset voltage controls the critical charge needed to upset the cell. The effect is demonstrated using a specially designed 2-micron n-well CMOS 4-kb test SRAM and a Po-208 5.1-MeV 0.61-LET alpha-particle source. This test SRAM has been made sensitive to alpha particles through the use of a cell offset voltage, and this has allowed a bench-level characterization in a laboratory setting. The experimental data are linked to a alpha-particle interaction physics and to SPICE circuit simulations through the alpha-particle collection depth. The collection depth is determined by two methods and found to be about 7 micron. In addition, alpha particles that struck outside the bloated drain were able to flip the SRAM cells. This lateral charge collection was observed to be more than 6 micron.

  4. Bioisosteric phentolamine analogs as selective human alpha(2)- versus alpha(1)-adrenoceptor ligands.

    PubMed

    Bavadekar, Supriya A; Hong, Seoung-Soo; Lee, Sang-Ii; Miller, Duane D; Feller, Dennis R

    2008-08-20

    Phentolamine is known to act as a competitive, non-subtype-selective alpha-adrenoceptor antagonist. In an attempt to improve alpha(2)- versus alpha(1)-adrenoceptor selectivity and alpha(2)-adrenoceptor subtype-selectivity, two new chemical series of bioisosteric phentolamine analogs were prepared and evaluated. These compounds were evaluated for binding affinities on alpha(1)- (alpha(1A)-, alpha(1B)-, alpha(1D)-) and alpha(2)- (alpha(2A)-, alpha(2B)-, alpha(2C)-) adrenoceptor subtypes that had been stably expressed in human embryonic kidney and Chinese hamster ovary cell lines, respectively. Methylation of the phenolic hydroxy group and replacement of the 4-methyl group of phentolamine with varying lipophilic substituents yielded bioisosteric analogs selective for the alpha(2)- versus alpha(1)-adrenoceptors. Within the alpha(2)-adrenoceptors, these analogs bound with higher affinity at the alpha(2A)- and alpha(2C)-subtypes as compared to the alpha(2B)-subtype. In particular, the t-butyl analog was found to be the most selective, its binding at the alpha(2C)-adrenoceptor (Ki=3.6 nM) being 37- to 173-fold higher than that at the alpha(1)-adrenoceptors, and around 2- and 19-fold higher than at the alpha(2A)- and alpha(2B)-adrenoceptors, respectively. Data from luciferase reporter gene assays confirmed the functional antagonist activities of selected compounds from the bioisosteric series on human alpha(1A)- and alpha(2C)-adrenoceptors. Thus, the results with these bioisosteric analogs of phentolamine provide a lead to the rational design of potent and selective alpha(2)-adrenoceptor ligands that may be useful in improving the therapeutic profile of this drug class for human disorders.

  5. Sensitive, Selective Test For Hydrazines

    NASA Technical Reports Server (NTRS)

    Roundbehler, David; Macdonald, Stephen

    1993-01-01

    Derivatives of hydrazines formed, then subjected to gas chromatography and detected via chemiluminescence. In method of detecting and quantifying hydrazine vapors, vapors reacted with dinitro compound to enhance sensitivity and selectivity. Hydrazine (HZ), monomethyl hydrazine, (MMH), and unsymmetrical dimethylhydrazine (UDMH) analyzed quantitatively and qualitatively, either alone or in mixtures. Vapors collected and reacted with 2,4-dinitrobenzaldehyde, (DNB), making it possible to concentrate hydrazine in derivative form, thereby increasing sensitivity to low initial concentrations. Increases selectivity because only those constituents of sample reacting with DNB concentrated for analysis.

  6. Untranslated region-dependent exclusive expression of high-sensitivity subforms of alpha4beta2 and alpha3beta2 nicotinic acetylcholine receptors.

    PubMed

    Briggs, Clark A; Gubbins, Earl J; Marks, Michael J; Putman, C Brent; Thimmapaya, Rama; Meyer, Michael D; Surowy, Carol S

    2006-07-01

    alpha4beta2 nicotinic acetylcholine receptors (nAChRs) are recognized as the principal nicotine binding site in brain. Recombinant alpha4beta2 nAChR demonstrate biphasic concentration-response relationships with low- and high-EC50 components. This study shows that untranslated regions (UTR) can influence expression of high-sensitivity subforms of alpha4beta2 and alpha3beta2 nAChR. Oocytes injected with alpha4 and beta2 RNA lacking UTR expressed biphasic concentration-response relationships for acetylcholine with high-sensitivity EC50 values of 0.5 to 2.5 microM (14-24% of the population) and low-sensitivity EC50 values of 110 to 180 microM (76-86%). In contrast, message with UTR expressed exclusively the high-sensitivity alpha4beta2 nAChR subform with an acetylcholine EC50 value of 2.2 microM. Additional studies revealed pharmacological differences between high- and low-sensitivity alpha4beta2 subforms. Whereas the antagonists dihydro-beta-erythroidine (IC50 of 3-6 nM) and methyllycaconitine (IC50 of 40-135 nM) were not selective between high- and low-sensitivity alpha4beta2, chlorisondamine, mecamylamine, and d-tubocurarine were, respectively, 100-, 8-, and 5-fold selective for the alpha4beta2 subform with low sensitivity to acetylcholine. Conversely, agonists that selectively activated the high-sensitivity alpha4beta2 subform with respect to efficacy as well as potency were identified. Furthermore, two of these agonists were shown to activate mouse brain alpha4beta2 as well as the ferret high-sensitivity alpha4beta2 expressed in Xenopus laevis oocytes. With the use of UTR-containing RNA, exclusive expression of a novel high-sensitivity alpha3beta2 nAChR was also achieved. These studies 1) provide further evidence for the existence of multiple subforms of alpha4beta2 nAChR, 2) extend that to alpha3beta2 nAChR, 3) demonstrate UTR influence on beta2-containing nAChR properties, and 4) reveal compounds that interact with alpha4beta2 in a subform-selective manner.

  7. Selective sorting of alpha-granule proteins.

    PubMed

    Italiano, J E; Battinelli, E M

    2009-07-01

    One of the main functions of blood platelets is to secrete a variety of substances that can modify a developing thrombus, regulate the growth of the vasculature, promote wound repair, and contribute to cell-adhesive events. A majority of this vast array of secreted proteins are stored in alpha-granules. Until recently, it was assumed that platelets contained one homogeneous population of alpha-granules that undergo complete de-granulation during platelet activation. This review focuses on the mechanisms of alpha-granule biogenesis and secretion, with a particular emphasis on recent findings that clearly demonstrate that platelets contain distinct subpopulations of alpha-granules that undergo differential release during activation. We consider the implications of this new paradigm of platelet secretion, discuss mechanisms of alpha-granule biogenesis, and review the molecular basis of transport and delivery of alpha-granules to assembling platelets.

  8. cap alpha. /sub 2/-Adrenergic receptor-mediated sensitization of forskolin-stimulated cyclic AMP production

    SciTech Connect

    Jones, S.B.; Toews, M.L.; Turner, J.T.; Bylund, D.B.

    1987-03-01

    Preincubation of HT29 human colonic adenocarcinoma cells with ..cap alpha../sub 2/-adrenergic agonists resulted in a 10- to 20-fold increase in forskolin-stimulated cyclic AMP production as compared to cells preincubated without agonist. Similar results were obtained using either a (/sup 3/H)adenine prelabeling assay or a cyclic AMP radioimmunoassay to measure cyclic AMP levels. This phenomenon, which is termed sensitization, is ..cap alpha../sub 2/-adrenergic receptor-mediated and rapid in onset and reversal. Yohimbine, an ..cap alpha../sub 2/-adrenergic receptor-selective antagonist, blocked norepinephrine-induced sensitization, whereas prazosin (..cap alpha../sub 1/-adrenergic) and sotalol (..beta..-adrenergic) did not. The time for half-maximal sensitization was 5 min and the half-time for reversal was 10 min. Only a 2-fold sensitization of cyclic AMP production stimulated by vasoactive intestinal peptide was observed, indicating that sensitization is relatively selective for forskolin. Sensitization reflects an increased production of cyclic AMP and not a decreased degradation of cyclic AMP, since incubation with a phosphodiesterase inhibitor and forskolin did not mimic sensitization. Increasing the levels of cyclic AMP during the preincubation had no effect on sensitization, indicating that sensitization is not caused by decreased cyclic AMP levels during the preincubation. This rapid and dramatic sensitization of forskolin-stimulated cyclic AMP production is a previously unreported effect that can be added to the growing list of ..cap alpha../sub 2/-adrenergic responses that are not mediated by a decrease in cyclic AMP.

  9. Coefficient alpha and interculture test selection.

    PubMed

    Thurber, Steven; Kishi, Yasuhiro

    2014-04-01

    The internal consistency reliability of a measure can be a focal point in an evaluation of the potential adequacy of an instrument for adaptation to another cultural setting. Cronbach's alpha (α) coefficient is often used as the statistical index for such a determination. However, alpha presumes a tau-equivalent test and may constitute an inaccurate population estimate for multidimensional tests. These notions are expanded and examined with a Japanese version of a questionnaire on nursing attitudes toward suicidal patients, originally constructed in Sweden using the English language. The English measure was reported to have acceptable internal consistency (α) albeit the dimensionality of the questionnaire was not addressed. The Japanese scale was found to lack tau-equivalence. An alternative to alpha, "composite reliability," was computed and found to be below acceptable standards in magnitude and precision. Implications for research application of the Japanese instrument are discussed.

  10. Michrochannel plate for position sensitive alpha particle detection

    SciTech Connect

    Paul Hurley and James Tinsley

    2007-08-31

    This paper will describe the use of a microchannel plate (MCP) as the associated particle detector on a sealed tube neutron generator. The generator produces neutrons and associated alpha particles for use as a probe to locate and identify hidden explosives in associated particle imaging (API). The MCP measures the position in two dimensions and precise timing of the incident alpha particle, information which is then used to calculate the emission time and direction of the corresponding neutron. The MCP replaces the position-sensitive photomultipler tube (PSPMT) which, until recently, had been the only detector available for measuring position and timing for alpha particles in neutron generator applications. Where the PSPMT uses charge division for generating position information, a process that requires a first order correction to each pulse, the MCP uses delay-line timing, which requires no correction. The result is a device with an order of magnitude improvement in both position resolution and timing compared to the PSPMT. Hardware and software development and the measurements made to characterize the MCP for API applications are described.

  11. Enzymatic synthesis of a selective inhibitor for alpha-glucosidases: alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen.

    PubMed

    Lee, Young-Su; Lee, Myoung-Hee; Lee, Hee-Seob; Lee, Seung-Jae; Kim, Young-Wan; Zhang, Ran; Withers, Stephen G; Kim, Kwan Soo; Lee, Sung-Joon; Park, Kwan-Hwa

    2008-07-09

    Here, we describe the enzymatic synthesis of novel inhibitors using acarviosine-glucose as a donor and 3-alpha-D-glucopyranosylpropen (alphaGP) as an acceptor. Maltogenic amylase from Thermus sp. (ThMA) catalyzed the transglycosylation of the acarviosine moiety to alphaGP. The two major reaction products were isolated using chromatographies. Structural analyses revealed that acarviosine was transferred to either C-7 or C-9 of the alphaGP, which correspond to C-4 and C-6 of glucose. Both inhibited rat intestine alpha-glucosidase competitively but displayed a mixed-type inhibition mode against human pancreatic alpha-amylase. The alpha-acarviosinyl-(1-->7)-3-alpha-D-glucopyranosylpropen showed weaker inhibition potency than acarbose against both alpha-glycosidases. In contrast, the alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen exhibited a 3.0-fold improved inhibition potency against rat intestine alpha-glucosidase with 0.3-fold inhibition potency against human pancreatic alpha-amylase relative to acarbose. In conclusion, alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen is a novel alpha-glucosidase-selective inhibitor with 10-fold enhanced selectivity toward alpha-glucosidase over alpha-amylase relative to acarbose, and it could be applied as a potent hypoglycemic agent.

  12. Arrangement of Kv1 alpha subunits dictates sensitivity to tetraethylammonium.

    PubMed

    Al-Sabi, Ahmed; Shamotienko, Oleg; Dhochartaigh, Sorcha Ni; Muniyappa, Nagesh; Le Berre, Marie; Shaban, Hamdy; Wang, Jiafu; Sack, Jon T; Dolly, J Oliver

    2010-09-01

    Shaker-related Kv1 channels contain four channel-forming alpha subunits. Subfamily member Kv1.1 often occurs oligomerized with Kv1.2 alpha subunits in synaptic membranes, and so information was sought on the influence of their positions within tetramers on the channels' properties. Kv1.1 and 1.2 alpha genes were tandem linked in various arrangements, followed by expression as single-chain proteins in mammalian cells. As some concatenations reported previously seemed not to reliably position Kv1 subunits in their assemblies, the identity of expressed channels was methodically evaluated. Surface protein, isolated by biotinylation of intact transiently transfected HEK-293 cells, gave Kv1.1/1.2 reactivity on immunoblots with electrophoretic mobilities corresponding to full-length concatenated tetramers. There was no evidence of protein degradation, indicating that concatemers were delivered intact to the plasmalemma. Constructs with like genes adjacent (Kv1.1-1.1-1.2-1.2 or Kv1.2-1.2-1.1-1.1) yielded delayed-rectifying, voltage-dependent K(+) currents with activation parameters and inactivation kinetics slightly different from the diagonally positioned genes (Kv1.1-1.2-1.1-1.2 or 1.2-1.1-1.2-1.1). Pore-blocking petidergic toxins, alpha dendrotoxin, agitoxin-1, tityustoxin-Kalpha, and kaliotoxin, were unable to distinguish between the adjacent and diagonal concatamers. Unprecedentedly, external application of the pore-blocker tetraethylammonium (TEA) differentially inhibited the adjacent versus diagonal subunit arrangements, with diagonal constructs having enhanced susceptibility. Concatenation did not directly alter the sensitivities of homomeric Kv1.1 or 1.2 channels to TEA or the toxins. TEA inhibition of currents generated by channels made up from dimers (Kv1.1-1.2 and/or Kv1.2-1.1) was similar to the adjacently arranged constructs. These collective findings indicate that assembly of alpha subunits can be directed by this optimized concatenation, and that subunit

  13. Alpha-conotoxin-ImI: a competitive antagonist at alpha-bungarotoxin-sensitive neuronal nicotinic receptors in hippocampal neurons.

    PubMed

    Pereira, E F; Alkondon, M; McIntosh, J M; Albuquerque, E X

    1996-09-01

    In the present study, the patch-clamp technique was applied to rat hippocampal neurons or myoballs in culture to study the actions of alpha-conotoxin-ImI on the native alpha-bungarotoxin-sensitive, presumably alpha 7-bearing, neuronal nicotinic receptor and on other ligand-gated channels. Preexposure of the neurons for 5 min to alpha-conotoxin-ImI decreased the peak amplitude of alpha-BGT-sensitive currents (referred to as type IA currents) in a concentration-dependent fashion. Several lines of evidence revealed that the inhibitory effect of alpha-conotoxin-ImI was competitive with respect to the agonist (IC50 approximately 85 nM) and reversible by washing. At 300 nM, alpha-conotoxin-ImI decreased by only 15% the peak amplitude of ACh-evoked currents in rat myoballs, did not affect the activation of currents gated by gamma-aminobutyric acid, glycine, N-methyl-D-aspartate, kainate, or quisqualate in hippocampal neurons, but reduced to approximately 60% the peak amplitude and shortened the decay phase of curare-sensitive, serotonin-gated currents in these neurons. The competitive and reversible nature of the alpha-conotoxin-ImI-induced inhibition of native alpha 7-bearing neuronal nicotinic receptors makes this peptide a valuable new tool for the functional and structural characterization of these receptors in the central nervous system.

  14. Cortical alpha oscillations as a tool for auditory selective inhibition

    PubMed Central

    Strauß, Antje; Wöstmann, Malte; Obleser, Jonas

    2014-01-01

    Listening to speech is often demanding because of signal degradations and the presence of distracting sounds (i.e., “noise”). The question how the brain achieves the task of extracting only relevant information from the mixture of sounds reaching the ear (i.e., “cocktail party problem”) is still open. In analogy to recent findings in vision, we propose cortical alpha (~10 Hz) oscillations measurable using M/EEG as a pivotal mechanism to selectively inhibit the processing of noise to improve auditory selective attention to task-relevant signals. We review initial evidence of enhanced alpha activity in selective listening tasks, suggesting a significant role of alpha-modulated noise suppression in speech. We discuss the importance of dissociating between noise interference in the auditory periphery (i.e., energetic masking) and noise interference with more central cognitive aspects of speech processing (i.e., informational masking). Finally, we point out the adverse effects of age-related hearing loss and/or cognitive decline on auditory selective inhibition. With this perspective article, we set the stage for future studies on the inhibitory role of alpha oscillations for speech processing in challenging listening situations. PMID:24904385

  15. Synthesis of alpha-phosphorylated alpha,beta-unsaturated imines and their selective reduction to vinylogous and saturated alpha-aminophosphonates.

    PubMed

    Palacios, Francisco; Vicario, Javier; Maliszewska, Agnieszka; Aparicio, Domitila

    2007-03-30

    An efficient synthesis of alpha,beta-unsaturated imines derived from alpha-aminophosphonates is achieved through aza-Wittig reaction of P-trimethyl phosphazenes with beta,gamma-unsaturated alpha-ketophosphonates. Selective 1,2-reduction of such 1-azadienes affords beta,gamma-unsaturated alpha-aminophosphonates, phosphorylated analogs of vinylglycines, which are hydrogenated to yield saturated alpha-aminophosphonate derivatives.

  16. Lethal endotoxic shock using alpha-galactosylceramide sensitization as a new experimental model of septic shock.

    PubMed

    Ito, Hiroyasu; Koide, Naoki; Hassan, Ferdaus; Islam, Shamima; Tumurkhuu, Gantsetseg; Mori, Isamu; Yoshida, Tomoaki; Kakumu, Shinichi; Moriwaki, Hisataka; Yokochi, Takashi

    2006-03-01

    The effect of alpha-galactosylceramide (alpha-GalCer) on lipopolysaccharide (LPS)-mediated lethality was examined. Administration of LPS killed all mice pretreated with alpha-GalCer, but not untreated control mice. The lethal shock in alpha-GalCer-sensitized mice was accompanied by severe pulmonary lesions with marked infiltration of inflammatory cells and massive cell death. On the other hand, hepatic lesions were focal and mild. A number of cells in pulmonary and hepatic lesions underwent apoptotic cell death. alpha-GalCer sensitization was ineffective for the development of the systemic lethal shock in Valpha14-positive natural killer T cell-deficient mice. Sensitization with alpha-GalCer led to the circulation of a high level of interferon (IFN)-gamma and further augmented the production of tumor necrosis factor (TNF)-alpha in response to LPS. The lethal shock was abolished by the administration of anti-IFN-gamma or TNF-alpha antibody. Further, the lethal shock did not occur in TNF-alpha-deficient mice. Taken together, alpha-GalCer sensitization rendered mice very susceptible to LPS-mediated lethal shock, and IFN-gamma and TNF-alpha were found to play a critical role in the preparation and execution of the systemic lethal shock, respectively. The LPS-mediated lethal shock using alpha-GalCer sensitization might be useful for researchers employing experimental models of sepsis and septic shock.

  17. Method for characterizing the upset response of CMOS circuits using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor); Nixon, Robert H. (Inventor); Soli, George A. (Inventor)

    1995-01-01

    A method for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. A technique utilizing test structures to quickly and inexpensively characterize the SEU sensitivity of standard cell latches intended for use in a space environment. This bench-level approach utilizes alpha particles to induce upsets in a low LET sensitive 4-k bit test SRAM. This SRAM consists of cells that employ an offset voltage to adjust their upset sensitivity and an enlarged sensitive drain junction to enhance the cell's upset rate.

  18. Differential agonist sensitivity of glycine receptor alpha2 subunit splice variants.

    PubMed

    Miller, Paul S; Harvey, Robert J; Smart, Trevor G

    2004-09-01

    1. The glycine receptor (GlyR) alpha2A and alpha2B splice variants differ by a dual, adjacent amino acid substitution from alpha2A(V58,T59) to alpha2B(I58,A59) in the N-terminal extracellular domain. 2. Comparing the effects of the GlyR agonists, glycine, beta-alanine and taurine, on the GlyR alpha2 isoforms, revealed a significant increase in potency for all three agonists at the alpha2B variant. 3. The sensitivities of the splice variants to the competitive antagonist, strychnine, and to the biphasic modulator Zn(2+), were comparable. In contrast, the allosteric inhibitor picrotoxin was more potent on GlyR alpha2A compared to GlyR alpha2B receptors. 4. Coexpression of alpha2A or alpha2B subunits with the GlyR beta subunit revealed that the higher agonist potencies observed with the alpha2B homomer were retained for the alpha2Bbeta heteromer. 5. The identical sensitivity to strychnine combined with a reduction in the maximum current induced by the partial agonist taurine at the GlyR alpha2A homomer, suggested that the changed sensitivity to agonists is in accordance with a modulation of agonist efficacy rather than agonist affinity. 6. An effect on agonist efficacy was also supported by using a structural model of the GlyR, localising the region of splice variation to the proposed docking region between GlyR loop 2 and the TM2-3 loop, an area associated with channel activation. 7. The existence of a spasmodic mouse phenotype linked to a GlyR alpha1(A52S) mutation, the equivalent position to the source of the alpha2 splice variation, raises the possibility that the GlyR alpha2 splice variants may be responsible for distinct roles in neuronal function.

  19. The pharmacology of fluparoxan: a selective alpha 2-adrenoceptor antagonist.

    PubMed

    Halliday, C A; Jones, B J; Skingle, M; Walsh, D M; Wise, H; Tyers, M B

    1991-04-01

    1. This paper describes the pharmacology of the novel alpha 2-adrenoceptor antagonist fluparoxan (GR 50360) which is currently being studied clinically as a potential anti-depressant. Idazoxan and yohimbine were included in many studies for comparison. 2. In the rat isolated, field-stimulated vas deferens and the guinea-pig isolated, field-stimulated ileum preparations, fluparoxan was a reversible competitive antagonist of the inhibitory responses to the alpha 2-adrenoceptor agonist UK-14304 with pKB values of 7.87 and 7.89 respectively. In the rat isolated anococcygeus muscle, fluparoxan was a much weaker competitive antagonist of the contractile response to the alpha 1-adrenoceptor agonist phenylephrine with a pKB of 4.45 giving an alpha 2: alpha 1-adrenoceptor selectivity ratio of greater than 2500. 3. In the conscious mouse, fluparoxan (0.2-3.0 mg kg-1) was effective by the oral route and of similar potency to idazoxan in preventing clonidine-induced hypothermia and antinociception. In the rat, UK-14304-induced hypothermia (ED50 = 1.4 mg kg-1, p.o. or 0.5 mg kg-1, i.v.) and rotarod impairment (ED50 = 1.1 mg kg-1 p.o. or 1.3 mg kg-1, i.v.) were antagonized by fluparoxan. Fluparoxan, 0.67-6 mg kg-1, p.o., also prevented UK-14304-induced sedation and bradycardia in the dog. 4. In specificity studies fluparoxan had low or no affinity for a wide range of neurotransmitter receptor sites at concentrations up to at least 1 x 10(-5) M. It displayed weak affinity for 5-HT1A (pIC50 = 5.9) and 5-HT1B (pKi = 5.5) binding sites in rat brain. 5. We conclude that fluparoxan is a highly selective and potent alpha 2-adrenoceptor antagonist. The density of rat brain [3H]-dihydroalprenolol binding sites was reduced by 26% when fluparoxan was administered chronically for 6 days at a dose of 12 mg kg- 1 orally twice daily. The down-regulation of beta-adrenoceptors by fluparoxan is consistent with its antidepressant potential.

  20. TNF-alpha enhanced allergic sensitization to house dust mite in brown Norway rats.

    PubMed

    Lambert, A L; Selgrade, M K; Winsett, D W; Gilmour, M I

    2001-01-01

    We have recently demonstrated that pulmonary exposure to residual oil fly ash (ROFA) resulted in enhanced sensitization to house dust mite (HDM) and augmented the development of allergic lung disease after allergen challenge. This effect was associated with increased tumor necrosis factor alpha (TNF-alpha), a macrophage- and epithelial cell-derived cytokine that promotes granulocyte migration to the lung. The present study examined whether exogenous administration of TNF-alpha enhances sensitization to HDM. One day prior to pulmonary sensitization with 10 microg HDM (5 microg each on days 1 and 3), female Brown Norway rats were instilled via the trachea with either 2.0 microg recombinant rat TNF-alpha, 2.0 microg bovine serum albumin (BSA), or 1,000 microg ROFA, and were challenged with 10 microg HDM 14 days later. Antigen-induced immediate bronchoconstriction responses, antigen-specific immunoglobulin E (IgE) titers, lymphocyte proliferation, (cytokines (TNF-alpha and interleukin [IL]-13), and eosinophils were elevated in rats treated with ROFA or TNF-alpha compared with BSA-treated controls after HDM challenge. Intratracheal administration of anti-TNF-alpha monoclonal antibody during ROFA exposure did not reduce ROFA-enhanced lymphocyte proliferation or IgE titers, but had a trend for reduced pulmonary inflammation. This study demonstrates that TNF-alpha has similar adjuvant activity as ROFA, but other factors may fulfill this function when TNF-alpha activity is blocked.

  1. Selective versus Non-Selective Alpha-Blockade prior to Laparoscopic Adrenalectomy for Pheochromocytoma

    PubMed Central

    Randle, Reese W.; Balentine, Courtney J.; Pitt, Susan C.; Schneider, David F.; Sippel, Rebecca S.

    2016-01-01

    Background The optimal pre-operative alpha-blockade strategy is debated for patients undergoing laparoscopic adrenalectomy for pheochromocytomas. We evaluated the impact of selective versus non-selective alpha-blockade on intra-operative hemodynamics and post-operative outcomes. Methods We identified patients having laparoscopic adrenalectomy for pheochromocytomas from 2001-2015. As a marker of overall intra-operative hemodynamics, we combined systolic blood pressure (SBP) >200, SBP <80, SBP <80 AND >200, pulse >120, vasopressor infusion, and vasodilator infusion into a single variable. Similarly, the combination of vasopressor infusion in the post-anesthesia care unit (PACU) and need for intensive care unit (ICU) admission provided an overview of post-operative support. Results We identified 52 patients undergoing unilateral laparoscopic adrenalectomy for pheochromocytoma. Selective alpha-blockade (i.e. Doxazosin) was performed in 35% (n=18), and non-selective blockade with Phenoxybenzamine was performed in 65% (n=34). Demographics and tumor characteristics were similar between groups. Patients blocked selectively were more likely to have a SBP <80 (67%) than those blocked with phenoxybenzamine (35%) (p=0.03), but we found no significant difference in overall intra-operative hemodynamics between patients blocked selectively and non-selectively (p=0.09). Post-operatively, however, patients blocked selectively were more likely to require additional support with vasopressor infusions in the PACU or ICU admission (p=0.02). Hospital stay and complication rates were similar. Conclusion Laparoscopic adrenalectomy for pheochromocytoma is safe regardless of the pre-operative alpha-blockade strategy employed, but patients blocked selectively may have a higher incidence of transient hypotension during surgery and a greater need for post-operative support. These differences did not result in longer hospital stay or increased complications. PMID:27561909

  2. Sensitivities of five alpha continuous air monitors for detection of airborne {sup 239}Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  3. Sensitivities of five alpha continuous air monitors for detection of airborne sup 239 Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  4. Development of an optical lens based alpha-particle imaging system using position sensitive photomultiplier tube

    NASA Astrophysics Data System (ADS)

    Ando, Koki; Oka, Miki; Yamamoto, Seiichi

    2017-02-01

    We developed an optical lens based alpha-particle imaging system using position sensitive photomultiplier tube (PSPMT). The alpha-particle imaging system consists of an optical lens, an extension tube and a 1 in. square high quantum efficiency (HQE) type PSPMT. After a ZnS(Ag) is attached to subject, the scintillation image of ZnS(Ag) is focused on the photocathode of the PSPMT by the use of the optical lens. With this configuration we could image the alpha particle distribution with energy information without contacting to the subject. The spatial resolution and energy resolution were 0.8 mm FWHM and 50% FWHM at 5 mm from the optical lens, respectively. We could successfully image the alpha particle distribution in uranium ore. The developed alpha-particle imaging system will be a new tool for imaging alpha emitters with energy information without contacting the subject.

  5. Confirmation of mutant alpha 1 Na,K-ATPase gene and transcript in Dahl salt-sensitive/JR rats.

    PubMed

    Ruiz-Opazo, N; Barany, F; Hirayama, K; Herrera, V L

    1994-09-01

    As the sole renal Na,K-ATPase isozyme, the alpha 1 Na,K-ATPase accounts for all active transport of Na+ throughout the nephron. This role in renal Na+ reabsorption and the primacy of the kidney in hypertension pathogenesis make it a logical candidate gene for salt-sensitive genetic hypertension. An adenine (A)1079-->thymine (T) transversion, resulting in the substitution of glutamine276 with leucine and associated with decreased net 86Rb+ (K+) influx, was identified in Dahl salt-sensitive/JR rat kidney alpha 1 Na,K-ATPase cDNA. However, because a Taq polymerase chain reaction amplification-based reanalysis did not detect the mutant T1079 but rather only the wild-type A1079 alpha 1 Na,K-ATPase allele in Dahl salt-sensitive rat genomic DNA, we reexamined alpha 1 Na,K-ATPase sequences using Taq polymerase error-independent amplification-based analyses of genomic DNA (by polymerase allele-specific amplification and ligase chain reaction analysis) and kidney RNA (by mRNA-specific thermostable reverse transcriptase-polymerase chain reaction analysis). We also performed modified 3' mismatched correction analysis of genomic DNA using an exonuclease-positive thermostable DNA polymerase. All the confirmatory test results were concordant, confirming the A1079-->T transversion in the Dahl salt-sensitive alpha 1 Na,K-ATPase allele and its transcript, as well as the wild-type A1079 sequence in the Dahl salt-resistant alpha 1 Na,K-ATPase allele and its transcript. Documentation of a consistent Taq polymerase error that selectively substituted A at T1079 (sense strand) was obtained from Taq polymerase chain reaction amplification and subsequent cycle sequencing of reconfirmed known Dahl salt-sensitive/JR rat mutant T1079 alpha 1 cDNA M13 subclones. This Taq polymerase error results in the reversion of mutant sequence back to the wild-type alpha 1 Na,K-ATPase sequence. This identifies a site- and nucleotide-specific Taq polymerase misincorporation, suggesting that a structural

  6. Radioactive check sources for alpha and beta sensitive radiological instrumentation

    SciTech Connect

    Barnett, J.M.; Kane, J.E. II

    1994-06-01

    Since 1991, the Westinghouse Hanford Company has examined the construction and use of alpha and beta radioactive check sources for calibrating instruments and for performing response checks of instruments used for operational and environmental radiation detection. The purpose of using a radioactive check source is to characterize the response of a radiation monitoring instrument in the presence of radioactivity. To accurately calibrate the instrument and check its response, the check source used must emulate as closely as possible the actual physical and isotopic conditions being monitored. The isotope employed and the physical methods used to fabricate the check source (among other factors) determine instrument response. Although information from applicable national and international standards, journal articles, books, and government documents was considered, empirical data collected is most valuable when considering the type of source to use for a particular application. This paper presents source construction methods, use considerations, and standard recommendations. The results of a Hanford Site evaluation of several types of alpha and beta sources are also given.

  7. 5-Amino-pyrazoles as potent and selective p38[alpha] inhibitors

    SciTech Connect

    Das, Jagabandhu; Moquin, Robert V.; Dyckman, Alaric J.; Li, Tianle; Pitt, Sidney; Zhang, Rosemary; Shen, Ding Ren; McIntyre, Kim W.; Gillooly, Kathleen; Doweyko, Arthur M.; Newitt, John A.; Sack, John S.; Zhang, Hongjian; Kiefer, Susan E.; Kish, Kevin; McKinnon, Murray; Barrish, Joel C.; Dodd, John H.; Schieven, Gary L.; Leftheris, Katerina

    2012-02-07

    The synthesis and structure-activity relationships (SAR) of p38{alpha} MAP kinase inhibitors based on a 5-amino-pyrazole scaffold are described. These studies led to the identification of compound 2j as a potent and selective inhibitor of p38{alpha} MAP kinase with excellent cellular potency toward the inhibition of TNF{alpha} production. Compound 2j was highly efficacious in vivo in inhibiting TNF{alpha} production in an acute murine model of TNF{alpha} production. X-ray co-crystallography of a 5-amino-pyrazole analog 2f bound to unphosphorylated p38{alpha} is also disclosed.

  8. ATP-sensitive K+ channels mediate alpha 2D-adrenergic receptor contraction of arteriolar smooth muscle and reversal of contraction by hypoxia.

    PubMed

    Tateishi, J; Faber, J E

    1995-01-01

    Evidence in rat skeletal muscle suggests that local metabolic control of blood flow is facilitated by the reliance on alpha 2D-adrenergic receptors (ARs) for constriction of arterioles, together with the strong sensitivity of this constriction to inhibition by hypoxia. The present study examined the role of ATP-sensitive K+ (KATP) channels in the selective interaction between alpha 2D-ARs and hypoxia. Arterioles from rat cremaster muscle that possess both alpha 1D (alpha 1A/D)- and alpha 2D-AR subtypes were microcannulated, pressurized, and isolated in a tissue bath for measurement of changes in lumen diameter. Three studies first examined whether stimulation of alpha 2D- and alpha 1D-ARs involves inhibition of the KATP channel. Concentration-dependent constriction by the KATP antagonists glibenclamide (GLB, 0.01 to 10 mumol/L) and disopyramide (0.001 to 1 mmol/L) were abolished during alpha 2D stimulation but unaffected during alpha 1D stimulation. Activation of the KATP channel by cromakalim inhibited alpha 2D constriction with greater potency than alpha 1D (EC50, 7.0 +/- 0.2 versus 6.3 +/- 0.1). Finally, GLB (0.5 mumol/L) abolished dose-dependent alpha 2D constriction, whereas alpha 1D was unaffected. These data suggest that alpha 2D but not alpha 1D stimulation is "coupled" with closure of the KATP channel, leading to depolarization and contraction of vascular smooth muscle. In a second series, hypoxic (PO2, 6 mm Hg) inhibition of intrinsic smooth muscle tone was completely reversed by 0.1 mumol/L GLB, concentration-dependent GLB constriction was enhanced during hypoxia, and hypoxia reversed GLB constriction. These data confirm reports by others that hypoxia potentiates the activation of KATP channels, leading to hyperpolarization and relaxation. Finally, GLB constriction, which was abolished by concomitant alpha 2D stimulation, was completely restored by simultaneous activation of KATP channels with hypoxia. These findings suggest that the sensitivity of alpha

  9. Karyopherin alpha2: a control step of glucose-sensitive gene expression in hepatic cells.

    PubMed Central

    Guillemain, Ghislaine; Muñoz-Alonso, Maria J; Cassany, Aurélia; Loizeau, Martine; Faussat, Anne-Marie; Burnol, Anne-Françoise; Leturque, Armelle

    2002-01-01

    Glucose is required for an efficient expression of the glucose transporter GLUT2 and other genes. We have shown previously that the intracytoplasmic loop of GLUT2 can divert a signal, resulting in the stimulation of glucose-sensitive gene transcription. In the present study, by interaction with the GLUT2 loop, we have cloned the rat karyopherin alpha2, a receptor involved in nuclear import. The specificity of the binding was restricted to GLUT2, and not GLUT1 or GLUT4, and to karyopherin alpha2, not alpha1. When rendered irreversible by a cross-linking agent, this transitory interaction was detected in vivo in hepatocytes. A role for karyopherin alpha2 in the transcription of two glucose-sensitive genes was investigated by transfection of native and inactive green fluorescent protein-karyopherin alpha2 in GLUT2-expressing hepatoma cells. The amount of inactive karyopherin alpha2 receptor reduced, in a dose-dependent manner, the GLUT2 and liver pyruvate kinase mRNA levels by competition with endogenous active receptor. In contrast, the overexpression of karyopherin alpha2 did not significantly stimulate GLUT2 and liver pyruvate kinase mRNA accumulation in green fluorescent protein-sorted cells. The present study suggests that, in concert with glucose metabolism, karyopherin alpha2 transmits a signal to the nucleus to regulate glucose-sensitive gene expression. The transitory tethering of karyopherin alpha2 to GLUT2 at the plasma membrane might indicate that the receptor can load the cargo to be imported locally. PMID:11988093

  10. Karyopherin alpha2: a control step of glucose-sensitive gene expression in hepatic cells.

    PubMed

    Guillemain, Ghislaine; Muñoz-Alonso, Maria J; Cassany, Aurélia; Loizeau, Martine; Faussat, Anne-Marie; Burnol, Anne-Françoise; Leturque, Armelle

    2002-05-15

    Glucose is required for an efficient expression of the glucose transporter GLUT2 and other genes. We have shown previously that the intracytoplasmic loop of GLUT2 can divert a signal, resulting in the stimulation of glucose-sensitive gene transcription. In the present study, by interaction with the GLUT2 loop, we have cloned the rat karyopherin alpha2, a receptor involved in nuclear import. The specificity of the binding was restricted to GLUT2, and not GLUT1 or GLUT4, and to karyopherin alpha2, not alpha1. When rendered irreversible by a cross-linking agent, this transitory interaction was detected in vivo in hepatocytes. A role for karyopherin alpha2 in the transcription of two glucose-sensitive genes was investigated by transfection of native and inactive green fluorescent protein-karyopherin alpha2 in GLUT2-expressing hepatoma cells. The amount of inactive karyopherin alpha2 receptor reduced, in a dose-dependent manner, the GLUT2 and liver pyruvate kinase mRNA levels by competition with endogenous active receptor. In contrast, the overexpression of karyopherin alpha2 did not significantly stimulate GLUT2 and liver pyruvate kinase mRNA accumulation in green fluorescent protein-sorted cells. The present study suggests that, in concert with glucose metabolism, karyopherin alpha2 transmits a signal to the nucleus to regulate glucose-sensitive gene expression. The transitory tethering of karyopherin alpha2 to GLUT2 at the plasma membrane might indicate that the receptor can load the cargo to be imported locally.

  11. Fungal Sensitivity to and Enzymatic Degradation of the Phytoanticipin alpha-Tomatine.

    PubMed

    Sandrock, R W; Vanetten, H D

    1998-02-01

    ABSTRACT alpha-Tomatine, synthesized by Lycopersicon and some Solanum species, is toxic to a broad range of fungi, presumably because it binds to 3beta-hydroxy sterols in fungal membranes. Several fungal pathogens of tomato have previously been shown to be tolerant of this glycoalkaloid and to possess enzymes thought to be involved in its detoxification. In the current study, 23 fungal strains were examined for their ability to degrade alpha-tomatine and for their sensitivity to this compound and two breakdown products, beta(2)-tomatine and tomatidine. Both saprophytes and all five non-pathogens of tomato tested were sensitive, while all but two tomato pathogens (Stemphylium solani and Verticillium dahliae) were tolerant of alpha-to-matine (50% effective dose > 300 muM). Except for an isolate of Botrytis cinerea isolated from grape, no degradation products were detected when saprophytes and nonpathogens were grown in the presence of alpha-tomatine. All tomato pathogens except Phytophthora infestans and Pythium aphani-dermatum degraded alpha-tomatine. There was a strong correlation between tolerance to alpha-tomatine, the ability to degrade this compound, and pathogenicity on tomato. However, while beta(2)-tomatine and tomatidine were less toxic to most tomato pathogens, these breakdown products were inhibitory to some of the saprophytes and nonpathogens of tomato, suggesting that tomato pathogens may have multiple tolerance mechanisms to alpha-tomatine.

  12. Exposure-sensitization relationship for alpha-amylase allergens in the baking industry.

    PubMed

    Houba, R; Heederik, D J; Doekes, G; van Run, P E

    1996-07-01

    Fungal alpha-amylase is an important occupational allergen in the bakery industry. Epidemiologic studies focusing on the relationship between alpha-amylase allergen exposure and work-related respiratory allergy, however, have not been reported yet. In this cross-sectional study, sensitization to occupational allergens and work-related symptoms were studied in 178 bakery workers and related to allergen exposure. Alpha-amylase allergen concentrations were measured in personal dust samples, using a sandwich enzyme immunoassay. All workers were categorized into groups on the basis of their job histories and the alpha-amylase exposure levels of their job titles. Of all workers 25% had one or more work-related symptoms. As much as 9% of the bakery workers showed a positive skin prick test reaction to fungal amylase, and in 8% amylase-specific IgE was demonstrated. Alpha-amylase exposure and atopy appeared to be the most important determinants of skin sensitization, with prevalence ratios for atopy of 20.8 (95% CI, 2.74 to 158) and for medium and high alpha-amylase exposure groups of 8.6 (95% CI, 1.01 to 74) and 15.9 (95% CI, 1.95 to 129), respectively. Furthermore, a positive association was found between positive skin prick tests to alpha-amylase and work-related respiratory symptoms. In conclusion, this study has shown that there is a strong and positive relationship between alpha-amylase allergen exposure levels in bakeries and specific sensitization in bakery workers.

  13. Selective flow path alpha particle detector and method of use

    DOEpatents

    Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore

    2002-01-01

    A method and apparatus for monitoring alpha contamination are provided in which ions generated in the air surrounding the item, by the passage of alpha particles, are moved to a distant detector location. The parts of the item from which ions are withdrawn can be controlled by restricting the air flow over different portions of the apparatus. In this way, detection of internal and external surfaces separately, for instance, can be provided. The apparatus and method are particularly suited for use in undertaking alpha contamination measurements during the commissioning operations.

  14. Trypsin and alpha-chymotrypsin treatment abolishes glibenclamide sensitivity of KATP channels in rat ventricular myocytes.

    PubMed

    Nichols, C G; Lopatin, A N

    1993-03-01

    Cytoplasmic trypsin-treatment of voltage-sensitive potassium channels has been shown to cleave domains of the channel responsible for inactivation of the channel. Trypsin has also been reported to remove slow, irreversible inactivation, or run-down in ATP-sensitive potassium (KATP) channels. Cytoplasmic treatment of rat ventricular KATP channels with either crude, or pure trypsin (1-2 mg/ml) failed to prevent a slow run-down of channel activity. However, trypsin (porcine pancreatic type IX, or type II (Sigma Chem. Co.), or alpha-chymotrypsin (Sigma Chem. Co.) rapidly and irreversibly removed, or substantiallly decreased glibenclamide and tolbutamide-sensitivity of the channels without removing sensitivity to ATP. We conclude that glibenclamide must bind to either a separate protein, or to a separate domain on the channel in order to effect channel inhibition, and this domain is functionally disconnected from the channel by trypsin-, or alpha-chymotrypsin treatment.

  15. The HPV-16 E7 oncogene sensitizes malignant cells to IFN-alpha-induced apoptosis

    SciTech Connect

    Wang, Yisong

    2005-10-01

    Interferons (IFNs) exert antitumor effects in several human malignancies, but their mechanism of action is unclear. There is a great variability in sensitivity to IFN treatment depending on both tumor type and the individual patient. The reason for this variable sensitivity is not known. The fact that several IFN-induced anticellular effects are exerted through modulation of proto-oncogenes and tumor suppressor genes may indicate that the malignant genotype may be decisive in the cell's sensitivity to IFN. To determine if a deregulated oncogene could alter the cellular response to IFN, a mouse lymphoma cell line (J3D) was stably transfected with the viral human papillomavirus-16 (HPV-16) E7 oncogene. The E7-transfected cells and their respective mock-transfected sister clones were treated with IFN-{alpha} and examined for possible IFN-induced anticellular effects. We found that the E7-transfected clones were greatly sensitized to IFN-{alpha}-induced apoptosis compared with their mock-transfected counterparts. Induction of apoptosis in the transfected cells correlated with the ability of IFN to activate parts of the proapoptotic machinery specifically in these cells, including activation of caspases and the proapoptotic protein Bak. In summary, our data suggest that transfection of malignant cells with the E7 oncogene can sensitize them to IFN-{alpha}-induced apoptosis. This demonstrates that an oncogenic event may alter the cellular sensitivity to IFN and might also have implications for treatment of HPV related diseases with IFN.

  16. Molecularly imprinted solid phase extraction for the selective HPLC determination of alpha-tocopherol in bay leaves.

    PubMed

    Puoci, F; Cirillo, G; Curcio, M; Iemma, F; Spizzirri, U G; Picci, N

    2007-06-19

    A new sorbent for molecularly imprinted solid phase extraction (MISPE) was synthesized to extract and purify alpha-tocopherol (alpha-TP) from vegetable sources. Molecularly imprinted polymers (MIP) were synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent using a photo-polymerization procedure. A thermo-polymerization was also performed but no imprinting effect in the resulting materials was raised. The proposed MISPE protocol could overcome the drawback of traditional detection methods, which require pre-treatments of the samples. The possibility to obtain the selective recognition of alpha-TP from natural samples in aqueous mixtures represents one of the main advantages of our materials. Our procedure involves the direct HPLC injection of eluate without any treatment and above all the use of no toxic and biocompatible organic solvents. After the evaluation of the selectivity of the alpha-TP imprinted polymers, the performance of these materials as solid phase extraction (SPE) sorbents was investigated. Our MISPE-HPLC procedure has a high sensitivity, LOD and LOQ were 3.49x10(-7) and 1.16x10(-6) mol L(-1), respectively, as well as good precision (intraday precision below 3.3% and interday precisions below 6.5%) and recovery (60%). Thus, it can be successfully used for the purification of alpha-TP from bay leaves.

  17. Selective presynaptic insectotoxin (alpha-latroinsectotoxin) isolated from black widow spider venom.

    PubMed

    Magazanik, L G; Fedorova, I M; Kovalevskaya, G I; Pashkov, V N; Bulgakov, O V; Grishin, E V

    1992-01-01

    A homogenous protein of 120,000 mol. wt isolated from black widow spider (Lactrodectus mactans tredecimguttatus) venom and referred to as alpha-latroinsectotoxin was highly potent (4 nM) in the induction of an increase of the frequency of miniature excitatory postsynaptic potentials in blowfly (Calliphora vicina) larvae neuromuscular preparations. In the frog nerve ending, however, even 50 nM alpha-latroinsectotoxin failed to affect transmitter release. Pretreatment of insect preparations with alpha-latrotoxin or frog preparations with alpha-latroinsectotoxin did not prevent the specific effect of consequent applications of alpha-latroinsectotoxin (insect) and alpha-latrotoxin (frog), respectively. The binding of labelled [125I]alpha-latroinsectotoxin to insect and [125I]alpha-latrotoxin to bovine membrane preparations was saturable and highly specific. The presynaptic effect, but not the binding of alpha-latroinsectotoxin, was dependent on the presence of divalent cations in the external medium. Mg2+ could readily substitute for Ca2+ and increase of transmitter release induced by alpha-latroinsectotoxin also occurred in Ca(2+)-free solutions. Pretreatment of preparations with 300 micrograms/ml concanavalin A completely abolished both the presynaptic effect of alpha-latroinsectotoxin and its binding to insect membrane preparations. Thus, the phenomenology of alpha-latroinsectotoxin action on insects resembles in general that described for the action of alpha-latrotoxin on vertebrates. The selectivity of alpha-latrotoxin and alpha-latroinsectotoxin seems to be due to differences in the structure of neurotoxin receptors in nerve endings of vertebrates and insects, although the mode of presynaptic action has a great deal in common.

  18. Developmental changes in the role of a pertussis toxin sensitive guanine nucleotide binding protein in the rat cardiac alpha sub 1 -adrenergic system

    SciTech Connect

    Han, H.M.

    1989-01-01

    During development, the cardiac alpha{sub 1}-adrenergic chronotropic response changes from positive in the neonate to negative in the adult. This thesis examined the possibility of a developmental change in coupling of a PT-sensitive G-protein to the alpha{sub 1}-adrenergic receptor. Radioligand binding experiments performed with the iodinated alpha{sub 1}-selective radioligand ({sup 125}I)-I-2-({beta}-(4-hydroxphenyl)ethylaminomethyl)tetralone (({sup 125}I)-IBE 2254) demonstrated that the alpha{sub 1}-adrenergic receptor is coupled to a G-protein in both neonatal and adult rat hearts. However, in the neonate the alpha{sub 1}-adrenergic receptor is coupled to a PT-insensitive G-protein, whereas in the adult the alpha{sub 1}-adrenergic receptor is coupled to both a PT-insensitive and a PT-sensitive G-protein. Consistent with the results from binding experiments, PT did not have any effect on the alpha{sub 1}-mediated positive chronotropic response in the neonate, whereas in the adult the alpha{sub 1}-mediated negative chronotropic response was completely converted to a positive one after PT-treatment. This thesis also examined the possibility of an alteration in coupling of the alpha{sub 1}-adrenergic receptor to its effector under certain circumstances such as high potassium (K{sup +}) depolarization in nerve-muscle (NM) co-cultures, a system which has been previously shown to be a convenient in vitro model to study the mature inhibitory alpha{sub 1}-response.

  19. alpha7 Nicotinic acetylcholine receptor knockout selectively enhances ethanol-, but not beta-amyloid-induced neurotoxicity.

    PubMed

    de Fiebre, Nancyellen C; de Fiebre, Christopher M

    2005-01-03

    The alpha7 subtype of nicotinic acetylcholine receptor (nAChR) has been implicated as a potential site of action for two neurotoxins, ethanol and the Alzheimer's disease related peptide, beta-amyloid. Here, we utilized primary neuronal cultures of cerebral cortex from alpha7 nAChR null mutant mice to examine the role of this receptor in modulating the neurotoxic properties of subchronic, "binge" ethanol and beta-amyloid. Knockout of the alpha7 nAChR gene selectively enhanced ethanol-induced neurotoxicity in a gene dosage-related fashion. Susceptibility of cultures to beta-amyloid induced toxicity, however, was unaffected by alpha7 nAChR gene null mutation. Further, beta-amyloid did not inhibit the binding of the highly alpha7-selective radioligand, [(125)I]alpha-bungarotoxin. On the other hand, in studies in Xenopus oocytes ethanol efficaciously inhibited alpha7 nAChR function. These data suggest that alpha7 nAChRs modulate the neurotoxic effects of binge ethanol, but not the neurotoxicity produced by beta-amyloid. It is hypothesized that inhibition of alpha7 nAChRs by ethanol provides partial protection against the neurotoxic properties of subchronic ethanol.

  20. Potent and selective agonists of alpha-melanotropin (alphaMSH) action at human melanocortin receptor 5; linear analogs of alpha-melanotropin.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Cabello, M Angeles; Maroto, Marta; Teran, Ana

    2007-05-01

    Alpha-melanotropin, Ac-Ser(1)-Tyr-Ser-Met-Glu-His(6)-Phe(7)-Arg(8)-Trp(9)-Gly-Lys-Pro-Val(13)-NH(2)(1), is a non-selective endogenous agonist for the melanocortin receptor 5; the receptor present in various peripheral tissues and in the brain, cortex and cerebellum. Most of the synthetic analogs of alphaMSH, including a broadly used and more potent the NDP-alphaMSH peptide, Ac-Ser(1)-Tyr-Ser-Nle(4)-Glu-His(6)-D-Phe(7)-Arg(8)-Trp(9)-Gly-Lys-Pro-Val(13)-NH(2), are also not particularly selective for MC5R. To elucidate physiological functions of the melanocortin receptor 5 in rodents and humans, the receptor subtype selective research tools are needed. We report herein syntheses and pharmacological evaluation in vitro of several analogs of NDP-alphaMSH which are highly potent and specific agonists for the human MC5R. The new linear peptides, of structures and solubility properties similar to those of the endogenous ligand alphaMSH, are exemplified by compound 7, Ac-Ser(1)-Tyr-Ser-Met-Glu-Oic(6)-D-4,4'-Bip(7)-Pip(8)-Trp(9)-Gly-Lys-Pro-Val(13)-NH(2) (Oic: octahydroindole-2-COOH, 4,4'-Bip: 4,4'-biphenylalanine, Pip: pipecolic acid), shortly NODBP-alphaMSH, which has an IC(50)=0.74 nM (binding assay) and EC(50)=0.41 (cAMP production assay) at hMC5R nM and greater than 3500-fold selectivity with respect to the melanocortin receptors 1b, 3 and 4. A shorter peptide derived from NODBP-alphaMSH: Ac-Nle-Glu-Oic(6)-D-4,4'-Bip(7)-Pip(8)-Trp(9) -NH(2) (17) was measured to be an agonist only 10-fold less potent at hMC5R than the full length parent peptide. In the structure of this smaller analog, the Nle-Glu-Oic(6)-D-4,4'-Bip(7)-Pip(8) segment was found to be critical for high agonist potency, while the C-terminal Trp(9) residue was shown to be required for high hMC5R selectivity versus hMC1b,3,4R.

  1. Sensitivity of Selected Arenaviruses to a Human Interferon.

    DTIC Science & Technology

    1979-02-25

    A97 3 5U~ ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FR-ETC F/6 6/5 I SENSITIVITY OF SELECTED ARENAVIRUSES TO A HUMAN INTERFERON. (U) U FEB 79...TYPEOF REPORT & PERIOD COVERED Sensitivity of Selected Arenaviruses to a Human Interim - Interferon - / - 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR a...Human interferon, interferon sensitivity, human interferon bioassay, BS-C-l cells, Detroit 532 cells, Arenaviruses , vesicular stomatitis virus. O

  2. Selective non-steroidal inhibitors of 5 alpha-reductase type 1.

    PubMed

    Occhiato, Ernesto G; Guarna, Antonio; Danza, Giovanna; Serio, Mario

    2004-01-01

    The enzyme 5 alpha-reductase (5 alpha R) catalyses the reduction of testosterone (T) into the more potent androgen dihydrotestosterone (DHT). The abnormal production of DHT is associated to pathologies of the main target organs of this hormone: the prostate and the skin. Benign prostatic hyperplasia (BPH), prostate cancer, acne, androgenetic alopecia in men, and hirsutism in women appear related to the DHT production. Two isozymes of 5 alpha-reductase have been cloned, expressed and characterized (5 alpha R-1 and 5 alpha R-2). They share a poor homology, have different chromosomal localization, enzyme kinetic parameters, and tissue expression patterns. Since 5 alpha R-1 and 5 alpha R-2 are differently distributed in the androgen target organs, a different involvement of the two isozymes in the pathogenesis of prostate and skin disorders can be hypothesized. High interest has been paid to the synthesis of inhibitors of 5 alpha-reductase for the treatment of DHT related pathologies, and the selective inhibition of any single isozyme represents a great challenge for medical and pharmaceutical research in order to have more specific drugs. At present, no 5 alpha R-1 inhibitor is marketed for the treatment of 5 alpha R-1 related pathologies but pharmaceutical research is very active in this field. This paper will review the major classes of 5 alpha R inhibitors focusing in particular on non-steroidal inhibitors and on structural features that enhance the selectivity versus the type 1 isozyme. Biological tests to assess the inhibitory activity towards the two 5 alpha R isozymes will be also discussed.

  3. Contribution of nicotinic receptors to the function of synapses in the central nervous system: the action of choline as a selective agonist of alpha 7 receptors.

    PubMed

    Albuquerque, E X; Pereira, E F; Braga, M F; Alkondon, M

    1998-01-01

    The alpha 7-nicotinic receptor (nAChR)-selective agonist choline and nAChR-subtype-selective antagonists led to the discovery that activation of both alpha 7 and alpha 4 beta 2 nAChRs located in CA1 interneurons in slices taken from the rat hippocampus facilitates the tetrodotoxin (TTX)-sensitive release of gamma-aminobutyric acid (GABA). Experiments carried out in cultured hippocampal neurons not only confirmed that preterminal alpha 7 and alpha 4 beta 2 nAChRs modulate the TTX-sensitive release of GABA, but also demonstrated that evoked release of GABA is reduced by rapid exposure of the neurons to acetylcholine (ACh, 10 microM-1 mM) in the presence of the muscarinic receptor antagonist atropine (1 microM). This effect of ACh, which is fully reversible and concentration-dependent, is partially blocked by superfusion of the cultured neurons with external solution containing either the alpha 7-nAChR-selective antagonist methyllycaconitine (MLA, 1 nM) or the alpha 4 beta 2-nAChR-selective antagonist dihydro-beta-erythroidine (DH beta E, 100 nM). A complete blockade of ACh-induced reduction of evoked release of GABA was achieved only when the neurons were perfused with external solution containing both MLA and DH beta E, suggesting that activation of both alpha 7 and alpha 4 beta 2 nAChRs modulates the evoked release of GABA from hippocampal neurons. Such mechanisms may account for the apparent involvement of nAChRs in the psychological effects of tobacco smoking, in brain disorders (e.g., schizophrenia and epilepsy), and in physiological processes, including cognition and nociception.

  4. Alpha-2 adrenoceptors are present in rat aorta smooth muscle cells, and their action is mediated by ATP-sensitive K(+) channels.

    PubMed

    Fauaz, G; Feres, T; Borges, A C; Paiva, T B

    2000-10-01

    The role of alpha(2)-adrenoceptors in the response of aorta smooth muscle rings to the alpha(2)-adrenoceptors agonists UK 14,304 and clonidine was studied. Stimulation by 1 - 10 nM UK 14,304 caused dose-dependent relaxant responses in BaCl(2)-contracted endothelium-denuded aorta rings, and hyperpolarization in rings with or without endothelium, which were inhibited by yohimbine and glibenclamide, but not affected by prazosin, propranolol, apamin or iberiotoxin. At higher concentrations (10 nM - 10 microM) UK 14,304 also induced a depolarizing effect which was potentiated by yohimbine and inhibited by prazosin. These results indicate that UK 14,304 acts on alpha(2)-adrenoceptors at lower concentrations and on both alpha(1)- and alpha(2)-adrenoceptors above 10 nM. In rings, with or without endothelium, noradrenaline had a depolarizing effect which was inhibited by prazosin. Adrenaline did not affect the membrane potential but in the presence of prazosin caused hyperpolarization, which was inhibited by yohimbine and glibenclamide. These results indicate that noradrenaline is more selective for alpha(1)-, whereas adrenaline has similar affinities for alpha(1)- and alpha(2)-adrenoceptors. In aortae with endothelium, L-NNA caused a small depolarization but did not affect the hyperpolarization induced by UK 14,304, indicating that NO is not involved in that response. Glibenclamide induced a small depolarization in aortae, with or without endothelium, indicating that ATP-sensitive K(+) channels may play a role in maintaining the smooth muscle's membrane potential. Our results indicate that, in rat aorta, alpha(2)-adrenoceptors are also present in the smooth muscle, and that these receptors act through small-conductance ATP-sensitive K(+) channels.

  5. Expression of alpha subunit of alpha glucosidase II in adult mouse brain regions and selective organs

    PubMed Central

    Anji, Antje; Miller, Hayley; Raman, Chandrasekar; Phillips, Mathew; Ciment, Gary; Kumari, Meena

    2014-01-01

    Alpha glucosidase II (GII), a resident of endoplasmic reticulum (ER) and an important enzyme in folding of nascent glycoproteins, is heterodimeric consisting of alpha (GIIα) and beta (GIIβ) subunits. The catalytic GIIα subunit with the help of mannose 6-phosphate receptor homology (MRH) domain of GIIβ sequentially hydrolyzes two α-1-3-linked glucose residues in the 2nd step of N-linked oligosaccharide-mediated protein folding. The soluble GIIα subunit is retained in the ER through its interaction with the HDEL-containing GIIβ subunit. N-glycosylation and correct protein folding is crucial for protein stability, trafficking, and cell surface expression of several proteins in the brain. Alterations in N-glycosylation lead to abnormalities in neuronal migration and mental retardation, various neurodegenerative diseases, and invasion of malignant gliomas. Inhibitors of GII are used to inhibit cell proliferation and migration in a variety of different pathologies such as viral infection, cancer and diabetes. In spite of the widespread usage of GIIα inhibitory drugs and the role of GIIα in brain function little is known about its expression in brain and other tissues. Here, we report generation of a highly specific chicken antibody to GIIα subunit and its characterization by Western blotting and immunoprecipitation using cerebral cortical extracts. Using this antibody we show that the GIIα protein is highly expressed in testis, kidney, and lung, with the least amount in heart. GIIα polypeptide levels in whole brain were comparable to spleen. However, higher expression of GIIα protein was detected in cerebral cortex reflecting its continuous requirement in correct folding of cell surface proteins. PMID:25131991

  6. Glutathione regulation of redox-sensitive signals in tumor necrosis factor-alpha-induced vascular endothelial dysfunction.

    PubMed

    Tsou, Tsui-Chun; Yeh, Szu Ching; Tsai, Feng-Yuan; Chen, Jein-Wen; Chiang, Huai-Chih

    2007-06-01

    We investigated the regulatory role of glutathione in tumor necrosis factor-alpha (TNF-alpha)-induced vascular endothelial dysfunction as evaluated by using vascular endothelial adhesion molecule expression and monocyte-endothelial monolayer binding. Since TNF-alpha induces various biological effects on vascular cells, TNF-alpha dosage could be a determinant factor directing vascular cells into different biological fates. Based on the adhesion molecule expression patterns responding to different TNF-alpha concentrations, we adopted the lower TNF-alpha (0.2 ng/ml) to rule out the possible involvement of other TNF-alpha-induced biological effects. Inhibition of glutathione synthesis by l-buthionine-(S,R)-sulfoximine (BSO) resulted in down-regulations of the TNF-alpha-induced adhesion molecule expression and monocyte-endothelial monolayer binding. BSO attenuated the TNF-alpha-induced nuclear factor-kappaB (NF-kappaB) activation, however, with no detectable effect on AP-1 and its related mitogen-activated protein kinases (MAPKs). Deletion of an AP-1 binding site in intercellular adhesion molecule-1 (ICAM-1) promoter totally abolished its constitutive promoter activity and its responsiveness to TNF-alpha. Inhibition of ERK, JNK, or NF-kappaB attenuates TNF-alpha-induced ICAM-1 promoter activation and monocyte-endothelial monolayer binding. Our study indicates that TNF-alpha induces adhesion molecule expression and monocyte-endothelial monolayer binding mainly via activation of NF-kappaB in a glutathione-sensitive manner. We also demonstrated that intracellular glutathione does not modulate the activation of MAPKs and/or their downstream AP-1 induced by lower TNF-alpha. Although AP-1 activation by the lower TNF-alpha was not detected in our systems, we could not rule out the possible involvement of transiently activated MAPKs/AP-1 in the regulation of TNF-alpha-induced adhesion molecule expression.

  7. Independent Causal Contributions of Alpha- and Beta-Band Oscillations during Movement Selection

    PubMed Central

    Stolk, Arjen; Marshall, Tom R.; Esterer, Sophie; Sharp, Poppy; Dijkerman, H. Chris; de Lange, Floris P.; Toni, Ivan

    2016-01-01

    To select a movement, specific neuronal populations controlling particular features of that movement need to be activated, whereas other populations are downregulated. The selective (dis)inhibition of cortical sensorimotor populations is governed by rhythmic neural activity in the alpha (8–12 Hz) and beta (15–25 Hz) frequency range. However, it is unclear whether and how these rhythms contribute independently to motor behavior. Building on a recent dissociation of the sensorimotor alpha- and beta-band rhythms, we test the hypothesis that the beta-band rhythm governs the disinhibition of task-relevant neuronal populations, whereas the alpha-band rhythm suppresses neurons that may interfere with task performance. Cortical alpha- and beta-band rhythms were manipulated with transcranial alternating current stimulation (tACS) while human participants selected how to grasp an object. Stimulation was applied at either 10 or 20 Hz and was imposed on the sensorimotor cortex contralaterally or ipsilaterally to the grasping hand. In line with task-induced changes in endogenous spectral power, the effect of the tACS intervention depended on the frequency and site of stimulation. Whereas tACS stimulation generally increased movement selection times, 10 Hz stimulation led to relatively faster selection times when applied to the hemisphere ipsilateral to the grasping hand, compared with other stimulation conditions. These effects occurred selectively when multiple movements were considered. These observations functionally differentiate the causal contribution of alpha- and beta-band oscillations to movement selection. The findings suggest that sensorimotor beta-band rhythms disinhibit task-relevant populations, whereas alpha-band rhythms inhibit neuronal populations that could interfere with movement selection. SIGNIFICANCE STATEMENT This study shows dissociable effects of 10 Hz and 20 Hz tACS on the duration of movement selection. These observations have two elements of

  8. EEG epoch selection: lack of alpha rhythm improves discrimination of Alzheimer's disease.

    PubMed

    Fraga, Francisco J; Oliveira, Eliezyer F; Kanda, Paulo A M

    2016-08-01

    In this work we propose a detailed EEG epoch selection method and compare epochs with rare and abundant alpha rhythm (AR) of patients with Alzheimer's disease (AD) and normal controls. Epochs were classified as Dominant Alpha Scenario (DAS) and Rare Alpha Scenario (RAS) according to the AR percentage (energy within the 8-13 Hz bandwidth) in O1, O2 and Oz electrodes. Participants were divided into four groups: 17 DAS controls (N1), 15 DAS mild-AD patients (AD1), 12 RAS controls (N2) and 15 RAS mild-AD patients (AD2). We found out that scenario factor (DAS vs. RAS, two-way ANOVA) is significant over a great amount of electrode-bandwidth situations. Furthermore, one-way ANOVA showed significant differences between RAS AD and RAS controls in much more situations as compared to DAS. This is the first study using AD awake EEG reporting the decisive influence of alpha rhythm on epoch selection, where our results revealed that, contrary to what was initially expected, EEG epochs with poor alpha (RAS) discriminate mild AD much better than those presenting richer alpha content (DAS).

  9. alpha-conotoxin AuIB selectively blocks alpha3 beta4 nicotinic acetylcholine receptors and nicotine-evoked norepinephrine release.

    PubMed

    Luo, S; Kulak, J M; Cartier, G E; Jacobsen, R B; Yoshikami, D; Olivera, B M; McIntosh, J M

    1998-11-01

    Neuronal nicotinic acetylcholine receptors (nAChRs) with putative alpha3 beta4-subunits have been implicated in the mediation of signaling in various systems, including ganglionic transmission peripherally and nicotine-evoked neurotransmitter release centrally. However, progress in the characterization of these receptors has been hampered by a lack of alpha3 beta4-selective ligands. In this report, we describe the purification and characterization of an alpha3 beta4 nAChR antagonist, alpha-conotoxin AuIB, from the venom of the "court cone," Conus aulicus. We also describe the total chemical synthesis of this and two related peptides that were also isolated from the venom. alpha-Conotoxin AuIB blocks alpha3 beta4 nAChRs expressed in Xenopus oocytes with an IC50 of 0.75 microM, a kon of 1.4 x 10(6) min-1 M-1, a koff of 0.48 min-1, and a Kd of 0.5 microM. Furthermore, alpha-conotoxin AuIB blocks the alpha3 beta4 receptor with >100-fold higher potency than other receptor subunit combinations, including alpha2 beta2, alpha2 beta4, alpha3 beta2, alpha4 beta2, alpha4 beta4, and alpha1 beta1 gamma delta. Thus, AuIB is a novel, selective probe for alpha3 beta4 nAChRs. AuIB (1-5 microM) blocks 20-35% of the nicotine-stimulated norepinephrine release from rat hippocampal synaptosomes, whereas nicotine-evoked dopamine release from striatal synaptosomes is not affected. Conversely, the alpha3 beta2-specific alpha-conotoxin MII (100 nM) blocks 33% of striatal dopamine release but not hippocampal norepinephrine release. This suggests that in the respective systems, alpha3 beta4-containing nAChRs mediate norepinephrine release, whereas alpha3 beta2-containing receptors mediate dopamine release.

  10. Coordinated balancing of muscle oxidative metabolism through PGC-1{alpha} increases metabolic flexibility and preserves insulin sensitivity

    SciTech Connect

    Summermatter, Serge; Santos, Gesa

    2011-04-29

    Highlights: {yields} PGC-1{alpha} enhances muscle oxidative capacity. {yields} PGC-1{alpha} promotes concomitantly positive and negative regulators of lipid oxidation. {yields} Regulator abundance enhances metabolic flexibility and balances oxidative metabolism. {yields} Balanced oxidation prevents detrimental acylcarnitine and ROS generation. {yields} Absence of detrimental metabolites preserves insulin sensitivity -- Abstract: The peroxisome proliferator-activated receptor {gamma} coactivator 1{alpha} (PGC-1{alpha}) enhances oxidative metabolism in skeletal muscle. Excessive lipid oxidation and electron transport chain activity can, however, lead to the accumulation of harmful metabolites and impair glucose homeostasis. Here, we investigated the effect of over-expression of PGC-1{alpha} on metabolic control and generation of insulin desensitizing agents in extensor digitorum longus (EDL), a muscle that exhibits low levels of PGC-1{alpha} in the untrained state and minimally relies on oxidative metabolism. We demonstrate that PGC-1{alpha} induces a strictly balanced substrate oxidation in EDL by concomitantly promoting the transcription of activators and inhibitors of lipid oxidation. Moreover, we show that PGC-1{alpha} enhances the potential to uncouple oxidative phosphorylation. Thereby, PGC-1{alpha} boosts elevated, yet tightly regulated oxidative metabolism devoid of side products that are detrimental for glucose homeostasis. Accordingly, PI3K activity, an early phase marker for insulin resistance, is preserved in EDL muscle. Our findings suggest that PGC-1{alpha} coordinately coactivates the simultaneous transcription of gene clusters implicated in the positive and negative regulation of oxidative metabolism and thereby increases metabolic flexibility. Thus, in mice fed a normal chow diet, over-expression of PGC-1{alpha} does not alter insulin sensitivity and the metabolic adaptations elicited by PGC-1{alpha} mimic the beneficial effects of endurance training

  11. Occipital alpha activity during stimulus processing gates the information flow to object-selective cortex.

    PubMed

    Zumer, Johanna M; Scheeringa, René; Schoffelen, Jan-Mathijs; Norris, David G; Jensen, Ole

    2014-10-01

    Given the limited processing capabilities of the sensory system, it is essential that attended information is gated to downstream areas, whereas unattended information is blocked. While it has been proposed that alpha band (8-13 Hz) activity serves to route information to downstream regions by inhibiting neuronal processing in task-irrelevant regions, this hypothesis remains untested. Here we investigate how neuronal oscillations detected by electroencephalography in visual areas during working memory encoding serve to gate information reflected in the simultaneously recorded blood-oxygenation-level-dependent (BOLD) signals recorded by functional magnetic resonance imaging in downstream ventral regions. We used a paradigm in which 16 participants were presented with faces and landscapes in the right and left hemifields; one hemifield was attended and the other unattended. We observed that decreased alpha power contralateral to the attended object predicted the BOLD signal representing the attended object in ventral object-selective regions. Furthermore, increased alpha power ipsilateral to the attended object predicted a decrease in the BOLD signal representing the unattended object. We also found that the BOLD signal in the dorsal attention network inversely correlated with visual alpha power. This is the first demonstration, to our knowledge, that oscillations in the alpha band are implicated in the gating of information from the visual cortex to the ventral stream, as reflected in the representationally specific BOLD signal. This link of sensory alpha to downstream activity provides a neurophysiological substrate for the mechanism of selective attention during stimulus processing, which not only boosts the attended information but also suppresses distraction. Although previous studies have shown a relation between the BOLD signal from the dorsal attention network and the alpha band at rest, we demonstrate such a relation during a visuospatial task, indicating

  12. Examination by radioligand binding of the alpha1 adrenoceptors in the mesenteric arterial vasculature during the development of salt-sensitive hypertension.

    PubMed

    Caveney, S W; Taylor, D A; Fleming, W W

    1997-09-01

    Previous experiments have suggested that the vascular smooth muscle of Dahl salt-sensitive (DS) rats may possess a difference in the alpha1-adrenoceptor population or its transduction processes compared to Dahl salt-resistant (DR) rats. The purpose of the current research is to study the role of alpha1-adrenoceptors in the specific supersensitivity to norepinephrine (NE) seen prior to and early in the development of hypertension in the DS rat. Experiments in isolated perfused superior mesenteric arterial vasculature from DS rats chronically fed a high (7%) salt diet for 5 days or 3 weeks, in the absence or presence of an elevation in systolic blood pressure, respectively, demonstrated a specific supersensitivity to NE relative to DR rats. The enhanced responsiveness was specific to NE after 5 days of high salt since no differences in sensitivity of these preparations was observed to either KCl or 5-HT. A small but significant elevation in sensitivity to KCl following 3 weeks of treatment suggests that multiple factors may contribute to tissue responsiveness at this time. Radioligand binding experiments were performed using [125I]-HEAT to study the alpha1-adrenoceptor population and its subtypes. Saturation experiments using membranes prepared from the superior mesenteric arterial vasculature or mesenteric arterial branches showed no significant differences in overall alpha1-adrenoceptor population between DS and DR rats fed a high-salt diet for 5 days or 3 weeks. Competition experiments using membranes prepared from the superior mesenteric arterial branches in the presence of the alpha1A-subtype selective antagonist 5-methylurapidil showed two binding sites (high and low affinity) in these resistance vessels but no significant differences in nature or ratio of these sites between the DS and DR groups. These results suggest that changes in the alpha1-adrenoceptor population are not responsible for the specific supersensitivity to NE, which may be an early event in

  13. A SUCCESSFUL BROADBAND SURVEY FOR GIANT Ly{alpha} NEBULAE. I. SURVEY DESIGN AND CANDIDATE SELECTION

    SciTech Connect

    Prescott, Moire K. M.; Dey, Arjun; Jannuzi, Buell T.

    2012-04-01

    Giant Ly{alpha} nebulae (or Ly{alpha} 'blobs') are likely sites of ongoing massive galaxy formation, but the rarity of these powerful sources has made it difficult to form a coherent picture of their properties, ionization mechanisms, and space density. Systematic narrowband Ly{alpha} nebula surveys are ongoing, but the small redshift range covered and the observational expense limit the comoving volume that can be probed by even the largest of these surveys and pose a significant problem when searching for such rare sources. We have developed a systematic search technique designed to find large Ly{alpha} nebulae at 2 {approx}< z {approx}< 3 within deep broadband imaging and have carried out a survey of the 9.4 deg{sup 2} NOAO Deep Wide-Field Survey Booetes field. With a total survey comoving volume of Almost-Equal-To 10{sup 8} h{sup -3}{sub 70} Mpc{sup 3}, this is the largest volume survey for Ly{alpha} nebulae ever undertaken. In this first paper in the series, we present the details of the survey design and a systematically selected sample of 79 candidates, which includes one previously discovered Ly{alpha} nebula.

  14. Interferon-. alpha. selectively activates the. beta. isoform of protein kinase C through phosphatidylcholine hydrolysis

    SciTech Connect

    Pfeffer, L.M.; Saltiel, A.R. ); Strulovici, B. )

    1990-09-01

    The early events that occur after interferon binds to discrete cell surface receptors remain largely unknown. Human leukocyte interferon (interferon-{alpha}) rapidly increases the binding of ({sup 3}H)phorbol dibutyrate to intact HeLa cells a measure of protein kinase C activation, and induces the selective translocation of the {beta} isoform of protein kinase C from the cytosol to the particulate fraction of HeLa cells. The subcellular distribution of the {alpha} and {epsilon} isoforms is unaffected by interferon-{alpha} treatment. Activation of protein kinase C by phorbol esters mimics the inhibitory action of interferon-{alpha} on HeLa cell proliferation and down-regulation of protein kinase C blocks the induction of antiviral activity by interferon-{alpha} in HeLa cells. Increased phosphatidylcholine hydrolysis and phosphorylcholine production is accompanied by diacylglycerol production in response to interferon. However, inositol phospholipid turnover and free intracellular calcium concentration are unaffected. These results suggest that the transient increase in diacylglycerol, resulting from phosphatidylcholine hydrolysis, may selectively activate the {beta} isoform of protein kinase C. Moreover, the activation of protein kinase C is a necessary element in interferon action on cells.

  15. Ovine cardiac Na,K-ATPase: isolation by means of selective solubilization in Lubrol and the effect of 1 alpha,2 alpha-epoxyscillirosidin on this enzyme.

    PubMed

    Venter, P A; Naudé, R J; Oelofsen, W; Swan, G E

    1997-01-01

    The inhibition of cardiac Na,K-ATPase by 1 alpha,2 alpha-epoxyscillirosidin is the principal cause of poisoning of cattle by the tulip, Homeria pallida. The ultimate goals of this study were to study the interaction between 1 alpha,2 alpha-epoxyscillirosidin and ovine Na,K-ATPase by means of inhibition and displacement binding studies. Ovine cardiac Na,K-ATPase was isolated in membrane-bound form by means of deoxycholate treatment, high-speed ultracentrifugation, NaI treatment and selective solubilization in Lubrol. The inhibition of ovine cardiac and commercial porcine cerebral cortex Na,K-ATPase by 1 alpha,2 alpha-epoxyscilirosidin and ouabain was studied using a discontinuous Na,K-ATPase assay. The binding of 1 alpha,2 alpha-epoxyscillirosidin, ouabain and digoxin to the above enzymes was compared using a displacement binding assay with [3H] oubain. The Lubrol-solubilized ovine cardiac Na,K-ATPase showed a specific activity of 0.3 U/mg with no ouabain insensitive activity. I50 values of 2.1 x 10(-8) and 2.7 x 10(-8) were obtained for the inhibition of this enzyme by 1 alpha,2 alpha-epoxyscillirosidin and ouabain, respectively. 1 alpha,2 alpha-Epoxyscillirosidin has a much higher KD value (1.5 x 10(-7) M), however, than ouabain (9.5 x 10(-9) M) and digoxin (1.7 x 10(-8) M) in displacement binding studies with [3H]ouabain. 1 alpha,2 alpha-Epoxyscillirosidin is a potent inhibitor of ovine cardiac Na,K-ATPase and is a slightly stronger inhibitor of the enzyme than ouabain. The anomalous result for the displacement of 1 alpha,2 alpha-epoxyscillirosidin from its receptor is either a result of different affinities that K+ has for the enzyme ouabain and enzyme-1 alpha,2 alpha-epoxyscillirosidin complexes or because of different complex stabilities of these complexes.

  16. Regulation by interferon alpha of immunoglobulin isotype selection and lymphokine production in mice

    PubMed Central

    1991-01-01

    Antigens and infectious agents that stimulate interferon alpha(IFN- alpha) production in mice induce antibody responses that are predominantly of the immunoglobulin (Ig)G2a isotype and contain little or no IgE. This suggested the possibility that IFN-alpha might have a role in directing Ig isotype selection. Consistent with this possibility, we have found that injection of mice with recombinant mouse IFN-alpha suppresses IgE secretion, enhances IgG2a secretion, and has no independent effect on IgG1 secretion in mice stimulated with a foreign anti-IgD antibody. Injection of mice with polyinosinic acid.polycytidylic acid (poly I.C), an inducer of macrophage IFN-alpha production, also suppresses the anti-IgD antibody-induced IgE response and stimulates the IgG2a response; these effects are blocked by a sheep antibody that neutralizes mouse IFN-alpha/beta. Both recombinant IFN- alpha and poly I.C have maximum IgE suppressive and IgG2a stimulatory effects when injected early in the anti-IgD antibody-induced immune response. Addition of IFN-alpha to mouse B cells cultured with lipopolysaccharide (LPS) + interleukin 4 (IL-4) suppresses both IgG1 and IgE production, but much less potently than IFN-gamma. IFN-alpha suppresses anti-IgD antibody-induced increases in the level of splenic IL-4 mRNA, but enhances the anti-IgD antibody-induced increase in the splenic level of IFN-gamma mRNA. These results are consistent with the effect of IFN-alpha on Ig isotype expression in mice, as IL-4 stimulates IgE and suppresses IgG2a secretion while IFN-gamma exerts opposite effects. These observations suggest that antigen presenting cells, by secreting IFN-alpha early in the course of an immune response, can influence the nature of that response both through direct effects on B cells and by influencing the differentiation of T cells. PMID:1940796

  17. Functional characterization of mongoose nicotinic acetylcholine receptor alpha-subunit: resistance to alpha-bungarotoxin and high sensitivity to acetylcholine.

    PubMed

    Asher, O; Lupu-Meiri, M; Jensen, B S; Paperna, T; Fuchs, S; Oron, Y

    1998-07-24

    The mongoose is resistant to snake neurotoxins. The mongoose muscle nicotinic acetylcholine receptor (AChR) alpha-subunit contains a number of mutations in the ligand-binding domain and exhibits poor binding of alpha-bungarotoxin (alpha-BTX). We characterized the functional properties of a hybrid (alpha-mongoose/beta gamma delta-rat) AChR. Hybrid AChRs, expressed in Xenopus oocytes, respond to acetylcholine with depolarizing current, the mean maximal amplitude of which was greater than that mediated by the rat AChR. The IC50 of alpha-BTX to the hybrid AChR was 200-fold greater than that of the rat, suggesting much lower affinity for the toxin. Hybrid AChRs exhibited an apparent higher rate of desensitization and higher affinity for ACh (EC50 1.3 vs. 23.3 microM for the rat AChR). Hence, changes in the ligand-binding domain of AChR not only affect the binding properties of the receptor, but also result in marked changes in the characteristics of the current.

  18. Interferon-resistant Daudi cells are deficient in interferon-alpha-induced ISGF3 alpha activation, but remain sensitive to the interferon-alpha-induced increase in ISGF3 gamma content.

    PubMed

    Dron, M; Tovey, M G

    1993-10-01

    Low levels of the transcription factor ISGF3 alpha were detected in the cytoplasm and nucleus of untreated Daudi cells, which increased markedly following interferon (IFN) treatment. In contrast no ISGF3 alpha was detected in an IFN-resistant clone of Daudi cells, DIF8, and only low levels were detected in these cells after IFN-alpha treatment. High levels of ISGF3 were produced in vitro, however, by the addition of ISGF3 alpha to extracts of IFN-treated DIF8 cells, indicating that IFN is unable to produce substantial amounts of functional ISGF3 alpha in DIF8 cells. A second clone of IFN-resistant Daudi cells, DIF3, also exhibited defective ISGF3 alpha production, which was restored to normal in the subclone DIF3REV5 that had reverted to high IFN sensitivity. Thus, the antiproliferative effect of IFN on Daudi cells and derived clones is closely related to the level of ISGF3 present in the nucleus of these cells. IFN-alpha, however, also enhances the content of ISGF3 gamma in IFN-resistant cells as well as certain proteins of unknown function, raising the possibility that a second pathway of IFN-alpha signal transduction, distinct from the ISGF3 pathway, remains functional in both DIF8 and DIF3 cells.

  19. Selective, tight-binding inhibitors of integrin alpha4beta1 that inhibit allergic airway responses.

    PubMed

    Lin, K c; Ateeq, H S; Hsiung, S H; Chong, L T; Zimmerman, C N; Castro, A; Lee, W C; Hammond, C E; Kalkunte, S; Chen, L L; Pepinsky, R B; Leone, D R; Sprague, A G; Abraham, W M; Gill, A; Lobb, R R; Adams, S P

    1999-03-11

    Integrin alpha4beta1 mediates leukocyte recruitment, activation, mediator release, and apoptosis inhibition, and it plays a central role in inflammatory pathophysiology. High-affinity, selective inhibitors of alpha4beta1, based on the Leu-Asp-Val (LDV) sequence from the alternatively spliced connecting segment-1 (CS-1) peptide of cellular fibronectin, are described that employ a novel N-terminal peptide "cap" strategy. One inhibitor, BIO-1211, was approximately 10(6)-fold more potent than the starting peptide and exhibited tight-binding properties (koff = 1.4 x 10(-4) s-1, KD = 70 pM), a remarkable finding for a noncovalent, small-molecule inhibitor of a protein receptor. BIO-1211 was also 200-fold selective for the activated form of alpha4beta1, and it stimulated expression of ligand-induced epitopes on the integrin beta1 subunit, a property consistent with occupancy of the receptor's ligand-binding site. Pretreatment of allergic sheep with a 3-mg nebulized dose of BIO-1211 inhibited early and late airway responses following antigen challenge and prevented development of nonspecific airway hyperresponsiveness to carbachol. These results show that highly selective and potent small-molecule antagonists can be identified to integrins with primary specificity for peptide domains other than Arg-Gly-Asp (RGD); they confirm the generality of integrins as small molecule targets; and they validate alpha4beta1 as a therapeutic target for asthma.

  20. Discovery of an Oxybenzylglycine Based Peroxisome Proliferator Activated Receptor Alpha Selective

    SciTech Connect

    Li, J.; Kennedy, L; Shi, Y; Tao, S; Ye, X; Chen, S; Wang, Y; Hernandez, A; Wang, W; et al.

    2010-01-01

    An 1,3-oxybenzylglycine based compound 2 (BMS-687453) was discovered to be a potent and selective peroxisome proliferator activated receptor (PPAR) {alpha} agonist, with an EC{sub 50} of 10 nM for human PPAR{alpha} and {approx}410-fold selectivity vs human PPAR{gamma} in PPAR-GAL4 transactivation assays. Similar potencies and selectivity were also observed in the full length receptor co-transfection assays. Compound 2 has negligible cross-reactivity against a panel of human nuclear hormone receptors including PPAR{delta}. Compound 2 demonstrated an excellent pharmacological and safety profile in preclinical studies and thus was chosen as a development candidate for the treatment of atherosclerosis and dyslipidemia. The X-ray cocrystal structures of the early lead compound 12 and compound 2 in complex with PPAR{alpha} ligand binding domain (LBD) were determined. The role of the crystal structure of compound 12 with PPAR{alpha} in the development of the SAR that ultimately resulted in the discovery of compound 2 is discussed.

  1. Octyl gallate: An antioxidant demonstrating selective and sensitive fluorescent property.

    PubMed

    Wang, Qing; Zhang, Yongkui; Li, Hui

    2017-03-15

    Octyl gallate (OG) is an internationally recognized antioxidant that demonstrates selective and sensitive fluorescent property. The fluorescence of OG can be selectively enhanced in the presence of human serum albumin (HSA) and bovine serum albumin (BSA). The specific structures of HSA and BSA provided the basic conditions for fluorescence enhancement. OG yielded approximately 49- and 11-fold increments in emission intensity in the presence of HSA and BSA at a molar ratio of 1:1, respectively. The lifetimes of HSA and BSA correspondingly decreased. A Förster resonance energy transfer phenomenon occurred during interaction between OG and HSA or BSA. Our in-depth investigation of OG-HSA interaction showed that formation of a stable complex was an important prerequisite to efficiently enhance the fluorescence of OG. The selective and sensitive fluorescent property of OG can possibly be used to determine OG concentration via the standard addition method, which must be performed under certain conditions.

  2. The relationship between red meat allergy and sensitization to gelatin and galactose-alpha-1,3-galactose

    PubMed Central

    Mullins, Raymond James; James, Hayley; Platts-Mills, Thomas A.E.; Commins, Scott

    2012-01-01

    Background We have observed patients clinically allergic to red meat and meat-derived gelatin. Objective We describe a prospective evaluation of the clinical significance of gelatin sensitization, the predictive value of a positive test and an examination of the relationship between allergic reactions to red meat and sensitization to gelatin and alpha-Gal. Methods Adult patients evaluated 1997-2011 for suspected allergy/anaphylaxis to medication, insect venom or food were skin tested with gelatin colloid. In vitro (ImmunoCap) testing was undertaken where possible. Results Positive gelatin tests were observed in 40/1335 individuals; 30/40 patients with red meat allergy (12 also clinically allergic to gelatin); 2/2 with gelatin colloid anaphylaxis; 4/172 with idiopathic anaphylaxis (all responded to intravenous gelatin challenge of 0.02 to 0.4g); 4/368 with drug allergy. Testing was negative in all patients with venom allergy (n=241), non-meat food allergy (n=222), and miscellaneous disorders (n=290). ImmunoCap was positive to alpha-Gal in 20/24 meat allergics and in 20/22 with positive gelatin skin tests. The results of gelatin skin testing and anti-alpha-Gal IgE were strongly correlated (r=0.46; P<0.01). Alpha-Gal was detected in bovine gelatin colloids at concentrations of ~ 0.44 to 0.52ug/gm gelatin by inhibition radioimmunoassay. Conclusion Most patients allergic to red meat were sensitized to gelatin and a subset was clinically allergic to both. The detection of alpha-Gal in gelatin and correlation between the results of alpha-Gal and gelatin testing raises the possibility that alpha-Gal IgE may be the target of reactivity to gelatin. The pathogenic relationship between tick bites and sensitization to red meat, alpha-Gal and gelatin (with or without clinical reactivity) remains uncertain. PMID:22480538

  3. Simultaneous quantification of GABAergic 3alpha,5alpha/3alpha,5beta neuroactive steroids in human and rat serum.

    PubMed

    Porcu, Patrizia; O'Buckley, Todd K; Alward, Sarah E; Marx, Christine E; Shampine, Lawrence J; Girdler, Susan S; Morrow, A Leslie

    2009-01-01

    The 3alpha,5alpha- and 3alpha,5beta-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone enhance GABAergic neurotransmission and produce inhibitory neurobehavioral and anti-inflammatory effects. Despite substantial information on the progesterone derivative (3alpha,5alpha)-3-hydroxypregnan-20-one (3alpha,5alpha-THP, allopregnanolone), the physiological significance of the other endogenous GABAergic neuroactive steroids has remained elusive. Here, we describe the validation of a method using gas chromatography-mass spectrometry to simultaneously identify serum levels of the eight 3alpha,5alpha- and 3alpha,5beta-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone. The method shows specificity, sensitivity and enhanced throughput compared to other methods already available for neuroactive steroid quantification. Administration of pregnenolone to rats and progesterone to women produced selective effects on the 3alpha,5alpha- and 3alpha,5beta-reduced neuroactive steroids, indicating differential regulation of their biosynthetic pathways. Pregnenolone administration increased serum levels of 3alpha,5alpha-THP (+1488%, p<0.001), (3alpha,5alpha)-3,21-dihydroxypregnan-20-one (3alpha,5alpha-THDOC, +205%, p<0.01), (3alpha,5alpha)-3-hydroxyandrostan-17-one (3alpha,5alpha-A, +216%, p<0.001), (3alpha,5alpha,17beta)-androstane-3,17-diol (3alpha,5alpha-A-diol, +190%, p<0.01). (3alpha,5beta)-3-hydroxypregnan-20-one (3alpha,5beta-THP) and (3alpha,5beta)-3-hydroxyandrostan-17-one (3alpha,5beta-A) were not altered, while (3alpha,5beta)-3,21-dihydroxypregnan-20-one (3alpha,5beta-THDOC) and (3alpha,5beta,17beta)-androstane-3,17-diol (3alpha,5beta-A-diol) were increased from undetectable levels to 271+/-100 and 2.4+/-0.9 pg+/-SEM, respectively (5/8 rats). Progesterone administration increased serum levels of 3alpha,5alpha-THP (+1806%, p<0.0001), 3alpha,5beta-THP (+575%, p<0.001), 3alpha,5alpha

  4. Assessing the SEU resistance of CMOS latches using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Buehler, M.; Blaes, B.; Nixon, R.

    1990-01-01

    The importance of Cosmic Rays on the performance of integrated circuits (IC's) in a space environment is evident in the upset rate of the Tracking and Data Relay Satellite (TDRS) launched in Apr. 1983. This satellite experiences a single-event-upset (SEU) per day which must be corrected from the ground. Such experience caused a redesign of the Galileo spacecraft with SEU resistant IC's. The solution to the SEU problem continues to be important as the complexity of spacecraft grows, the feature size of IC's decreases, and as space systems are designed with circuits fabricated at non-radiation hardened foundries. This paper describes an approach for verifying the susceptibility of CMOS latches to heavy-ion induced state changes. The approach utilizes alpha particles to induce the upsets in test circuits. These test circuits are standard cells that have offset voltages which sensitize the circuits to upsets. These results are then used to calculate the upsetability at operating voltages. In this study results are presented for the alpha particle upset of a six-transistor static random access memory (SRAM) cell. Then a methodology is described for the analysis of a standard-cell inverter latch.

  5. Selective precipitation of haptoglobin and alpha2-macroglobulin from human serum using Alocasia macrorhiza tuber protein.

    PubMed

    Nayak, B Shivananda; Ulloor, N Jagadish; Shivaraj, B

    2002-12-01

    Treatment of human serum with ammonium sulfate fraction (0-50%) of Alocasia macrorhiza tuber extract resulted in precipitation at neutral pH. The precipitate was dissolved at pH 10.5 and chromatographed on Sephadex G-100 column. Two protein peaks were resolved. While the first peak represented alpha2-macroglobulin and haptoglobin, the second peak accounted for specific Alocasia protein. Incidentally the Alocasia protein was shown to be responsible for selective and specific precipitation of alpha2-macroglobulin and haptoglobin from serum. Thus the plant protein in its pure form or in crude stage could be used for the rapid isolation of two of the prominent alpha2-globulins.

  6. Role of selective alpha and beta adrenergic receptor mechanisms in rat jejunal longitudinal muscle contractility.

    PubMed

    Seiler, Roland; Rickenbacher, Andreas; Shaw, Sidney; Haefliger, Simon; Balsiger, Bruno M

    2008-06-01

    Gut motility is modulated by adrenergic mechanisms. The aim of our study was to examine mechanisms of selective adrenergic receptors in rat jejunum. Spontaneous contractile activity of longitudinal muscle strips from rat jejunum was measured in 5-ml tissue chambers. Dose-responses (six doses, 10(-7) -3 x 10(-5)M) to norepinephrine (NE, nonspecific), phenylephrine (PH, alpha1), clonidine (C, alpha2), prenalterol (PR, beta1), ritodrine (RI, beta2), and ZD7714 (ZD, beta3) were evaluated with and without tetrodotoxin (TTX, nerve blocker). NE(3 x 10(-5)M) inhibited 74 +/- 5% (mean +/- SEM) of spontaneous activity. This was the maximum effect. The same dose of RI(beta2), PH(alpha1), or ZD(beta(3)) resulted in an inhibition of only 56 +/- 5, 43 +/- 4, 33 +/- 6, respectively. The calculated concentration to induce 50% inhibition (EC50) of ZD(beta3) was similar to NE, whereas higher concentrations of PH(alpha1) or RI(beta2) were required. C(alpha2) and PR(beta1) had no effect. TTX changed exclusively the EC50 of RI from 4.4 +/- 0.2 to 2.7 +/- 0.8% (p < 0.04). Contractility was inhibited by NE (nonspecific). PH(alpha1), RI(beta2), and ZD(beta3) mimic the effect of NE. TTX reduced the inhibition by RI. Our results suggest that muscular alpha1, beta2, and beta3 receptor mechanisms mediate adrenergic inhibition of contractility in rat jejunum. beta2 mechanisms seem to involve also neural pathways.

  7. The extraction and reconstitution of the alpha-cyanocinnamate-sensitive pyruvate transporter from castor bean mitochondria.

    PubMed

    Brailsford, M A; Thompson, A G; Kaderbhai, N; Beechey, R B

    1986-11-14

    The pyruvate carrier from castor bean mitochondria has been solubilized with Triton X-114 and partially purified using hydroxyapatite column chromatography. SDS-polyacrylamide gel electrophoresis of the hydroxyapatite-eluate showed that there were 6 major protein bands of Mr, 74kDa, 66kDa, 34kDa, 32kDa, 30kDa 12kDa. When the eluate was reconstituted into liposomes it was shown to catalyze a pyruvate exchange reaction which was sensitive to N-ethyl maleimide and a series of analogues of alpha-cyanocinnamate. The characteristics of this pyruvate exchange activity are similar to that found in intact mitochondria, and it is concluded that one or more proteins in the hydroxyapatite-eluate correspond to the pyruvate carrier.

  8. Selective calcium sensitivity in immature glioma cancer stem cells.

    PubMed

    Wee, Shimei; Niklasson, Maria; Marinescu, Voichita Dana; Segerman, Anna; Schmidt, Linnéa; Hermansson, Annika; Dirks, Peter; Forsberg-Nilsson, Karin; Westermark, Bengt; Uhrbom, Lene; Linnarsson, Sten; Nelander, Sven; Andäng, Michael

    2014-01-01

    Tumor-initiating cells are a subpopulation in aggressive cancers that exhibit traits shared with stem cells, including the ability to self-renew and differentiate, commonly referred to as stemness. In addition, such cells are resistant to chemo- and radiation therapy posing a therapeutic challenge. To uncover stemness-associated functions in glioma-initiating cells (GICs), transcriptome profiles were compared to neural stem cells (NSCs) and gene ontology analysis identified an enrichment of Ca2+ signaling genes in NSCs and the more stem-like (NSC-proximal) GICs. Functional analysis in a set of different GIC lines regarding sensitivity to disturbed homeostasis using A23187 and Thapsigargin, revealed that NSC-proximal GICs were more sensitive, corroborating the transcriptome data. Furthermore, Ca2+ drug sensitivity was reduced in GICs after differentiation, with most potent effect in the NSC-proximal GIC, supporting a stemness-associated Ca2+ sensitivity. NSCs and the NSC-proximal GIC line expressed a larger number of ion channels permeable to potassium, sodium and Ca2+. Conversely, a higher number of and higher expression levels of Ca2+ binding genes that may buffer Ca2+, were expressed in NSC-distal GICs. In particular, expression of the AMPA glutamate receptor subunit GRIA1, was found to associate with Ca2+ sensitive NSC-proximal GICs, and decreased as GICs differentiated along with reduced Ca2+ drug sensitivity. The correlation between high expression of Ca2+ channels (such as GRIA1) and sensitivity to Ca2+ drugs was confirmed in an additional nine novel GIC lines. Calcium drug sensitivity also correlated with expression of the NSC markers nestin (NES) and FABP7 (BLBP, brain lipid-binding protein) in this extended analysis. In summary, NSC-associated NES+/FABP7+/GRIA1+ GICs were selectively sensitive to disturbances in Ca2+ homeostasis, providing a potential target mechanism for eradication of an immature population of malignant cells.

  9. Imaging metals in biology: balancing sensitivity, selectivity and spatial resolution.

    PubMed

    Hare, Dominic J; New, Elizabeth J; de Jonge, Martin D; McColl, Gawain

    2015-10-07

    Metal biochemistry drives a diverse range of cellular processes associated with development, health and disease. Determining metal distribution, concentration and flux defines our understanding of these fundamental processes. A comprehensive analysis of biological systems requires a balance of analytical techniques that inform on metal quantity (sensitivity), chemical state (selectivity) and location (spatial resolution) with a high degree of certainty. A number of approaches are available for imaging metals from whole tissues down to subcellular organelles, as well as mapping metal turnover, protein association and redox state within these structures. Technological advances in micro- and nano-scale imaging are striving to achieve multi-dimensional and in vivo measures of metals while maintaining the native biochemical environment and physiological state. This Tutorial Review discusses state-of-the-art imaging technology as a guide to obtaining novel insight into the biology of metals, with sensitivity, selectivity and spatial resolution in focus.

  10. Tibolone is not converted by human aromatase to 7alpha-methyl-17alpha-ethynylestradiol (7alpha-MEE): analyses with sensitive bioassays for estrogens and androgens and with LC-MSMS.

    PubMed

    de Gooyer, Marcel E; Oppers-Tiemissen, Hendrika M; Leysen, Dirk; Verheul, Herman A M; Kloosterboer, Helenius J

    2003-03-01

    To exclude that aromatization plays a role in the estrogenic activity of tibolone, we studied the effect tibolone and metabolites on the aromatization of androstenedione and the aromatization of tibolone and its metabolites to 7alpha-methyl-17alpha-ethynylestradiol (7alpha-MEE) by human recombinant aromatase. Testosterone (T), 17alpha-methyltestosterone (MT), 19-nortestosterone (Nan), 7alpha-methyl-19-nortestosterone (MENT) and norethisterone (NET) were used as reference compounds. Sensitive in vitro bioassays with steroid receptors were used to monitor the generation of product and the reduction of substrate. LC-MSMS without derivatization was used for structural confirmation. A 10 times excess of tibolone and its metabolites did not inhibit the conversion of androstenedione to estrone by human recombinant aromatase as determined by estradiol receptor assay whereas T, MT, Nan, and MENT inhibited the conversion for 75, 53, 85 and 67%, respectively. Tibolone, 3alpha- and 3beta-hydroxytibolone were not converted by human aromatase whereas the estrogenic activity formed with the Delta4-isomer suggests a conversion rate of 0.2% after 120 min incubation. In contrast T, MT, Nan, and MENT were completely converted to their A-ring aromates within 15 min while NET could not be aromatized. Aromatization of T, MT, Nan and MENT was confirmed with LC-MSMS. Structure/function analysis indicated that the 17alpha-ethynyl-group prevents aromatization of (19-nor)steroids while 7alpha-methyl substitution had no effect. Our results with the sensitive estradiol receptor assays show that in contrast to reference compounds tibolone and its metabolites are not aromatized.

  11. Identification of a novel cyclosporin-sensitive element in the human tumor necrosis factor alpha gene promoter

    PubMed Central

    1993-01-01

    Tumor necrosis factor alpha (TNF-alpha), a cytokine with pleiotropic biological effects, is produced by a variety of cell types in response to induction by diverse stimuli. In this paper, TNF-alpha mRNA is shown to be highly induced in a murine T cell clone by stimulation with T cell receptor (TCR) ligands or by calcium ionophores alone. Induction is rapid, does not require de novo protein synthesis, and is completely blocked by the immunosuppressant cyclosporin A (CsA). We have identified a human TNF-alpha promoter element, kappa 3, which plays a key role in the calcium-mediated inducibility and CsA sensitivity of the gene. In electrophoretic mobility shift assays, an oligonucleotide containing kappa 3 forms two DNA protein complexes with proteins that are present in extracts from unstimulated T cells. These complexes appear in nuclear extracts only after T cell stimulation. Induction of the inducible nuclear complexes is rapid, independent of protein synthesis, and blocked by CsA, and thus, exactly parallels the induction of TNF-alpha mRNA by TCR ligands or by calcium ionophore. Our studies indicate that the kappa 3 binding factor resembles the preexisting component of nuclear factor of activated T cells. Thus, the TNF-alpha gene is an immediate early gene in activated T cells and provides a new model system in which to study CsA-sensitive gene induction in activated T cells. PMID:8376940

  12. Motion words selectively modulate direction discrimination sensitivity for threshold motion

    PubMed Central

    Pavan, Andrea; Skujevskis, Māris; Baggio, Giosuè

    2013-01-01

    Can speech selectively modulate the sensitivity of a sensory system so that, in the presence of a suitable linguistic context, the discrimination of certain perceptual features becomes more or less likely? In this study, participants heard upward or downward motion words followed by a single visual field of random dots moving upwards or downwards. The time interval between the onsets of the auditory and the visual stimuli was varied parametrically. Motion direction could be either discriminable (suprathreshold motion) or non-discriminable (threshold motion). Participants had to judge whether the dots were moving upward or downward. Results show a double dissociation between discrimination sensitivity (d′) and reaction times depending on whether vertical motion was above or at threshold. With suprathreshold motion, responses were faster for congruent directions of words and dots, but sensitivity was equal across conditions. With threshold motion, sensitivity was higher for congruent directions of words and dots, but responses were equally fast across conditions. The observed differences in sensitivity and response times were largest when the dots appeared 450 ms after word onset, that is, consistently with electrophysiology, at the time the up/down semantics of the word had become available. These data suggest that word meanings can alter the balance between signal and noise within the visual system and affect the perception of low-level sensory features. PMID:23596407

  13. Estimating the variation, autocorrelation, and environmental sensitivity of phenotypic selection.

    PubMed

    Chevin, Luis-Miguel; Visser, Marcel E; Tufto, Jarle

    2015-09-01

    Despite considerable interest in temporal and spatial variation of phenotypic selection, very few methods allow quantifying this variation while correctly accounting for the error variance of each individual estimate. Furthermore, the available methods do not estimate the autocorrelation of phenotypic selection, which is a major determinant of eco-evolutionary dynamics in changing environments. We introduce a new method for measuring variable phenotypic selection using random regression. We rely on model selection to assess the support for stabilizing selection, and for a moving optimum that may include a trend plus (possibly autocorrelated) fluctuations. The environmental sensitivity of selection also can be estimated by including an environmental covariate. After testing our method on extensive simulations, we apply it to breeding time in a great tit population in the Netherlands. Our analysis finds support for an optimum that is well predicted by spring temperature, and occurs about 33 days before a peak in food biomass, consistent with what is known from the biology of this species. We also detect autocorrelated fluctuations in the optimum, beyond those caused by temperature and the food peak. Because our approach directly estimates parameters that appear in theoretical models, it should be particularly useful for predicting eco-evolutionary responses to environmental change.

  14. Human fat cell alpha-2 adrenoceptors. I. Functional exploration and pharmacological definition with selected alpha-2 agonists and antagonists

    SciTech Connect

    Galitzky, J.; Mauriege, P.; Berlan, M.; Lafontan, M.

    1989-05-01

    This study was undertaken to investigate more fully the pharmacological characteristics of the human fat cell alpha-2 adrenoceptor. Biological assays were performed on intact isolated fat cells while radioligand binding studies were carried out with (/sup 3/H)yohimbine in membranes. These pharmacological studies brought: (1) a critical definition of the limits of the experimental conditions required for the exploration of alpha-2 adrenergic responsiveness on human fat cells and membranes; (2) an improvement in the pharmacological definition of the human fat cell postsynaptic alpha-2 adrenoceptor. Among alpha-2 agonists, UK-14,304 was the most potent and the relative order of potency was: UK-14,304 greater than p-aminoclonidine greater than clonidine = B-HT 920 greater than rilmenidine. For alpha-2 antagonists, the potency order was: yohimbine greater than idazoxan greater than SK F-86,466 much greater than benextramine; (3) a description of the impact of benextramine (irreversible alpha-1/alpha-2 antagonist) on human fat cell alpha-2 adrenergic receptors and on human fat cell function; the drug inactivates the alpha-2 adrenergic receptors with a minor impact on beta adrenergic receptors and without noticeable alterations of fat cell function as assessed by preservation of beta adrenergic and Al-adenosine receptor-mediated lipolytic responses; and (4) a definition of the relationship existing between alpha-2 adrenergic receptor occupancy, inhibition of adenylate cyclase activity and antilipolysis with full and partial agonists. The existence of a receptor reserve must be taken into account when evaluating alpha-2 adrenergic receptor distribution and regulation of human fat cells.

  15. Selective extinction drives taxonomic and functional alpha and beta diversities in island bird assemblages.

    PubMed

    Si, Xingfeng; Baselga, Andrés; Leprieur, Fabien; Song, Xiao; Ding, Ping

    2016-03-01

    Taxonomic diversity considers all species being equally different from each other and thus disregards species' different ecological functions. Exploring taxonomic and functional aspects of biodiversity simultaneously can better understand the processes of community assembly. We analysed taxonomic and functional alpha and beta diversities of breeding bird assemblages on land-bridge islands in the Thousand Island Lake, China. Given the high dispersal ability of most birds at this spatial scale (several kilometres), we predicted (i) selective extinction driving alpha and beta diversities after the creation of land-bridge islands of varying area and (ii) low taxonomic and functional beta diversities that were not correlated to spatial distance. Breeding birds were surveyed on 37 islands annually from 2007 to 2014. We decomposed beta diversity of breeding birds into spatial turnover and nestedness-resultant components, and related taxonomic and functional diversities to island area and isolation using power regression models (for alpha diversity) and multiple regression models on distance matrices (for beta diversity). We then ran simulations to assess the strength of the correlations between taxonomic and functional diversities. Results revealed that both taxonomic and functional alpha diversities increased with island area. The taxonomic nestedness-resultant and turnover components increased and decreased with difference in area, respectively, but functional counterparts did not. Isolation played a minor role in explaining alpha- and beta-diversity patterns. By partitioning beta diversity, we found low levels of overall taxonomic and functional beta diversities. The functional nestedness-resultant component dominated overall functional beta diversity, whereas taxonomic turnover was the dominant component for taxonomic beta diversity. The simulation showed that functional alpha and beta diversities were significantly correlated with taxonomic diversities, and the

  16. Distinctive selection mechanisms govern the T cell receptor repertoire of peripheral CD4-CD8- alpha/beta T cells

    PubMed Central

    1992-01-01

    The T cell receptor (TCR) repertoire of CD4+ and CD8+ alpha/beta T cells is heavily influenced by positive and negative selection events that occur during T cell development in the thymus. The coreceptors CD4 and CD8 appear to be essential for this selection to occur. To gain insight into whether T cells that express TCR alpha/beta but lack either coreceptor (CD4- CD8- TCR alpha/beta or alpha/beta double- negative [DN] cells) are also subject to positive and negative selection, and whether selection can occur in the absence of coreceptors, we have performed an extensive immunogenetic analysis of the TCR V beta repertoire of alpha/beta DN cells in lymph nodes of normal mice. Our results show that alpha/beta DN cells appear to be unaffected by clonal deletion of V beta 5 and V beta 11 in I-E- expressing mice, and do not undergo deletion of V beta 6- and V beta 8.1-expressing T cells in Mls-1a-positive mice. They are also unaffected by positive selection of V beta 17a+ T cells in the context of I-Aq. The results suggest that most selection events require the participation of CD4 and CD8, while alpha/beta DN cells are unselected. This argues that most alpha/beta DN cells probably have never expressed CD4 or CD8. However, a unique form of repertoire selection occurs: enrichment of V beta 17a+ alpha/beta DN cells in I-E+ mice. This could be an instance of coreceptor-independent selection. PMID:1512537

  17. Dopamine selectively sensitizes dopaminergic neurons to rotenone-induced apoptosis.

    PubMed

    Ahmadi, Ferogh A; Grammatopoulos, Tom N; Poczobutt, Andy M; Jones, Susan M; Snell, Laurence D; Das, Mita; Zawada, W Michael

    2008-05-01

    Among various types of neurons affected in Parkinson's disease, dopamine (DA) neurons of the substantia nigra undergo the most pronounced degeneration. Products of DA oxidation and consequent cellular damage have been hypothesized to contribute to neuronal death. To examine whether elevated intracellular DA will selectively predispose the dopaminergic subpopulation of nigral neurons to damage by an oxidative insult, we first cultured rat primary mesencephalic cells in the presence of rotenone to elevate reactive oxygen species. Although MAP2(+) neurons were more sensitive to rotenone-induced toxicity than type 1 astrocytes, rotenone affected equally both DA (TH(+)) neurons and MAP2(+) neurons. In contrast, when intracellular DA concentration was elevated, DA neurons became selectively sensitized to rotenone. Raising intracellular DA levels in primary DA neurons resulted in dopaminergic neuron death in the presence of subtoxic concentrations of rotenone. Furthermore, mitochondrial superoxide dismutase mimetic, manganese (III) meso-tetrakis (4-benzoic acid) porphyrin, blocked activation of caspase-3, and consequent cell death. Our results demonstrate that an inhibitor of mitochondrial complex I and increased cytosolic DA may cooperatively lead to conditions of elevated oxidative stress and thereby promote selective demise of dopaminergic neurons.

  18. Phage selection restores antibiotic sensitivity in MDR Pseudomonas aeruginosa.

    PubMed

    Chan, Benjamin K; Sistrom, Mark; Wertz, John E; Kortright, Kaitlyn E; Narayan, Deepak; Turner, Paul E

    2016-05-26

    Increasing prevalence and severity of multi-drug-resistant (MDR) bacterial infections has necessitated novel antibacterial strategies. Ideally, new approaches would target bacterial pathogens while exerting selection for reduced pathogenesis when these bacteria inevitably evolve resistance to therapeutic intervention. As an example of such a management strategy, we isolated a lytic bacteriophage, OMKO1, (family Myoviridae) of Pseudomonas aeruginosa that utilizes the outer membrane porin M (OprM) of the multidrug efflux systems MexAB and MexXY as a receptor-binding site. Results show that phage selection produces an evolutionary trade-off in MDR P. aeruginosa, whereby the evolution of bacterial resistance to phage attack changes the efflux pump mechanism, causing increased sensitivity to drugs from several antibiotic classes. Although modern phage therapy is still in its infancy, we conclude that phages, such as OMKO1, represent a new approach to phage therapy where bacteriophages exert selection for MDR bacteria to become increasingly sensitive to traditional antibiotics. This approach, using phages as targeted antibacterials, could extend the lifetime of our current antibiotics and potentially reduce the incidence of antibiotic resistant infections.

  19. Chronic nicotine blunts hypoxic sensitivity in perinatal rat adrenal chromaffin cells via upregulation of KATP channels: role of alpha7 nicotinic acetylcholine receptor and hypoxia-inducible factor-2alpha.

    PubMed

    Buttigieg, Josef; Brown, Stephen; Holloway, Alison C; Nurse, Colin A

    2009-06-03

    Fetal nicotine exposure blunts hypoxia-induced catecholamine secretion from neonatal adrenomedullary chromaffin cells (AMCs), providing a link between maternal smoking, abnormal arousal responses, and risk of sudden infant death syndrome. Here, we show that the mechanism is attributable to upregulation of K(ATP) channels via stimulation of alpha7 nicotinic ACh receptors (AChRs). These K(ATP) channels open during hypoxia, thereby suppressing membrane excitability. After in utero exposure to chronic nicotine, neonatal AMCs show a blunted hypoxic sensitivity as determined by inhibition of outward K(+) current, membrane depolarization, rise in cytosolic Ca(2+), and catecholamine secretion. However, hypoxic sensitivity could be unmasked in nicotine-exposed AMCs when glibenclamide, a blocker of K(ATP) channels, was present. Both K(ATP) current density and K(ATP) channel subunit (Kir 6.2) expression were significantly enhanced in nicotine-exposed cells relative to controls. The entire sequence could be reproduced in culture by exposing neonatal rat AMCs or immortalized fetal chromaffin (MAH) cells to nicotine for approximately 1 week, and was prevented by coincubation with selective blockers of alpha7 nicotinic AChRs. Additionally, coincubation with inhibitors of protein kinase C and CaM kinase, but not protein kinase A, prevented the effects of chronic nicotine in vitro. Interestingly, chronic nicotine failed to blunt hypoxia-evoked responses in MAH cells bearing short hairpin knockdown (>90%) of the transcription factor, hypoxia-inducible factor-2alpha (HIF-2alpha), suggesting involvement of the HIF pathway. The therapeutic potential of K(ATP) channel blockers was validated in experiments in which hypoxia-induced neonatal mortality in nicotine-exposed pups was significantly reduced after pretreatment with glibenclamide.

  20. Genome-Wide Screening of Alpha-Tocopherol Sensitive Genes in Heart Tissue from Alpha-Tocopherol Transfer Protein Null Mice (ATTP−/−)

    PubMed Central

    Vasu, Vihas T.; Hobson, Brad; Gohil, Kishorchandra; Cross, Carroll E.

    2009-01-01

    Alpha tocopherol transfer protein (ATTP) null mice (ATTP−/−) have a systemic deficiency of alpha-tocopherol (AT). The heart AT levels of ATTP−/− are <10% of those in ATTP+/+ mice. The genomic responses of heart to AT deficiency were determined in 3 months old male ATTP−/− mice and compared with their ATTP+/+ littermate controls using Affymetrix 430A 2.0 high density oligonucleotide arrays. Differential analysis of ~13,000 genes identified repression of genes related to immune system and activation of genes related to lipid metabolism and inflammation with no significant change in the expression of classical antioxidant genes (catalase, superoxide dismutase, glutathione peroxidase) in ATTP−/− as compared to ATTP+/+ mice. The present data identifies novel classes of AT sensitive genes in heart tissue. PMID:17382327

  1. alpha4beta2 nicotinic receptors with high and low acetylcholine sensitivity: pharmacology, stoichiometry, and sensitivity to long-term exposure to nicotine.

    PubMed

    Moroni, Mirko; Zwart, Ruud; Sher, Emanuele; Cassels, Bruce K; Bermudez, Isabel

    2006-08-01

    alpha4 and beta2 nicotinic acetylcholine receptor (nAChR) subunits expressed heterologously assemble into receptors with high (HS) and low (LS) sensitivity to acetylcholine (ACh); their relative proportions depend on the alpha4to beta2 ratio. In this study, injection of oocytes with 1:10 alpha4/beta2 subunit cDNA ratios favored expression of HS alpha4beta2 nAChRs, as evidenced by monophasic ACh concentration-response curves, whereas injections with 10:1 cDNA ratios favored expression of LS alpha4beta2 receptors. The stoichiometry was inferred from the shifts in the ACh EC(50) values caused by Leu to Thr mutations at position 9' of the second transmembrane domain of alpha4 and beta2. The 1:10 injection ratio produced the (alpha4)(2)(beta2)(3) stoichiometry, whereas 10:1 injections produced the (alpha4)(3)(beta2)(2) stoichiometry. The agonists epibatidine, 3-[2(S)-azetidinylmethoxy]pyridine (A-85380), 5-ethoxy-metanicotine (TC-2559), cytisine, and 3-Br-cytisine and the antagonists dihydro-beta-erythroidine and d-tubocurarine were more potent at HS receptors. TC-2559 was more efficacious than ACh at HS receptors but was a partial agonist at LS receptors. Epibatidine was more efficacious than ACh at LS receptors and a partial agonist at HS receptors. Cytisine and 5-halogenated cytisines had moderate efficacy at LS receptors but had almost no efficacy at HS receptors. By exploiting the differential effects of ACh, TC-2559 and 5-I-cytisine we evaluated the effects of long-term exposure to nicotine on HS and LS receptors expressed in Xenopus laevis oocytes after cDNA injections or microtransplantation of alpha4beta2 receptors assembled in human embryonic kidney 293 cells. We conclude that nicotine up-regulates HS alpha4beta2 receptors, probably by influencing the assembly of receptors rather than by altering the functional state of LS alpha4beta2 nAChRs.

  2. Selective sensitization of C-fiber nociceptors by hydrogen sulfide.

    PubMed

    Aoki, Yuka; Tsubota, Maho; Nishimoto, Yuta; Maeda, Yumi; Sekiguchi, Fumiko; Kawabata, Atsufumi

    2016-01-01

    We examined the effects of intraplantar (i.pl.) administration of NaHS, an H2S donor, known to cause T-type Ca(2+) channel (T-channel)-dependent mechanical hyperalgesia, on responsiveness to electric stimulation with 5, 250 and 2000 Hz sine waves (SW) that selectively excites C, Aδ and Aβ fibers, respectively. NaHS, given i.pl., caused behavioral hypersensitivity to SW stimulation at 5 Hz, but not 250 or 2000 Hz, in rats. NaHS also enhanced phosphorylation of spinal ERK following 5 Hz SW stimulation. Three distinct T-channel blockers abolished the NaHS-induced behavioral hypersensitivity to 5 Hz SW stimulation. Thus, H2S selectively sensitizes C-fiber nociceptors via T-channels.

  3. Selection of a 2-azabicyclo[2.2.2]octane-based alpha4beta1 integrin antagonist as an inhaled anti-asthmatic agent.

    PubMed

    Lawson, Edward C; Santulli, Rosemary J; Dyatkin, Alexey B; Ballentine, Scott A; Abraham, William M; Rudman, Sandra; Page, Clive P; de Garavilla, Lawrence; Damiano, Bruce P; Kinney, William A; Maryanoff, Bruce E

    2006-06-15

    The alpha4beta1 integrin, expressed on eosinophils and neutrophils, induces inflammation in the lung by facilitating cellular infiltration and activation. From a number of potent alpha4beta1 antagonists that we evaluated for safety and efficacy, 1 was selected as a lead candidate for anti-asthma therapy by the inhalation route. We devised an optimized stereoselective synthesis to facilitate the preparation of a sufficiently large quantity of 1 for assessment in vivo. Administration of 1 to allergen-sensitive sheep by inhalation blocked the late-phase response of asthma and abolished airway hyper-responsiveness at 24h following the antigen challenge. Additionally, the recruitment of inflammatory cells into the lungs was inhibited. Administration of 1 to ovalbumin-sensitized guinea pigs intraperitoneally blocked airway resistance and inhibited the recruitment of inflammatory cells.

  4. Relative sensitivity of some selected aquatic organisms to phenol

    SciTech Connect

    Tisler, T.; Zagorc-Koncan, J.

    1995-05-01

    Although the possibility of adverse effects of materials on organisms was recognized earlier, not until the 1940s or 1950s short-term acute tests with fishes were being studied. The fishes have become the most popular test organism because the effects of toxic substances in streams have been most evident on the fishes. Many other organisms bearing the important role in the environment live in the waters and began to be used in the toxicological research. Nowadays such great variety of test methods and organisms make the selection of the suitable toxicity test difficult. One or two species of test organisms only are often applied in the determination of the toxic substances or wastewaters. The toxicity test with daphnids is widely used due to its sensitivity to the great part of toxic substances. The purpose of our research was to determine the toxicity of phenol to some aquatic organisms from the group of bacteria, algae, crustacea and fishes, and to determine the most sensitive kind. Test organisms have been selected from three basic groups in the food chain (bacteria - decomposers, algae - producers and crustacea, fish - consumers). Phenol, an organic degradable substance that is a frequent contaminant in wastewaters, has been chosen for the test substance. 29 refs., 3 tabs.

  5. ASH structure alignment package: Sensitivity and selectivity in domain classification

    PubMed Central

    Standley, Daron M; Toh, Hiroyuki; Nakamura, Haruki

    2007-01-01

    Background Structure alignment methods offer the possibility of measuring distant evolutionary relationships between proteins that are not visible by sequence-based analysis. However, the question of how structural differences and similarities ought to be quantified in this regard remains open. In this study we construct a training set of sequence-unique CATH and SCOP domains, from which we develop a scoring function that can reliably identify domains with the same CATH topology and SCOP fold classification. The score is implemented in the ASH structure alignment package, for which the source code and a web service are freely available from the PDBj website . Results The new ASH score shows increased selectivity and sensitivity compared with values reported for several popular programs using the same test set of 4,298,905 structure pairs, yielding an area of .96 under the receiver operating characteristic (ROC) curve. In addition, weak sequence homologies between similar domains are revealed that could not be detected by BLAST sequence alignment. Also, a subset of domain pairs is identified that exhibit high similarity, even though their CATH and SCOP classification differs. Finally, we show that the ranking of alignment programs based solely on geometric measures depends on the choice of the quality measure. Conclusion ASH shows high selectivity and sensitivity with regard to domain classification, an important step in defining distantly related protein sequence families. Moreover, the CPU cost per alignment is competitive with the fastest programs, making ASH a practical option for large-scale structure classification studies. PMID:17407606

  6. Bench-level characterization of a CMOS standard-cell D-latch using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Blaes, B. R.; Soli, G. A.; Buehler, M. G.

    1991-01-01

    A methodology is described for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. Measurements were made on a 1.6-micron n-well CMOS 4-kb test SRAM irradiated with an Am-241 alpha-particle source. A collection depth of 6.09 micron was determined using these results and TRIM computer code. Using this collection depth and SPICE derived critical charge results on the latch design, an LET threshold of 34 MeV sq cm/mg was predicted. Heavy ion tests were then performed on the latch and an LET threshold of 41 MeV sq cm/mg was determined.

  7. Contribution of both Ca2+ entry and Ca2+ sensitization to the alpha1-adrenergic vasoconstriction of rat penile small arteries.

    PubMed

    Villalba, Nuria; Stankevicius, Edgaras; Garcia-Sacristán, Albino; Simonsen, Ulf; Prieto, Dolores

    2007-02-01

    Sympathetic adrenergic nerves maintain the flaccid state of the penis through the tonic release of norepinephrine that contracts trabecular and arterial smooth muscle. Simultaneous measurements of intracellular Ca(2+) concentration ([Ca(2+)](i)) and tension and experiments with alpha-toxin-permeabilized arteries were performed in branches of the rat dorsal penile artery to investigate the intracellular Ca(2+) signaling pathways underlying alpha(1)-adrenergic vasoconstriction. Phenylephrine increased both [Ca(2+)](i) and tension, these increases being abolished by extracellular Ca(2+) removal and reduced by about 50% by the L-type Ca(2+) channel blocker nifedipine (0.3 microM). Non-L-type Ca(2+) entry through store-operated channels was studied by inhibiting the sarcoplasmic reticulum Ca(2+)-ATPase with cyclopiazonic acid (CPA). CPA (30 microM) induced variable phasic contractions that were abolished by extracellular Ca(2+) removal and by the store-operated channels antagonist 2-aminoethoxydiphenyl borate (2-APB, 50 microM) and largely inhibited by nifedipine (0.3 microM). CPA induced a sustained increase in [Ca(2+)](i) that was reduced in a Ca(2+)-free medium. Under conditions of L-type channels blockade, Ca(2+) readmission after store depletion with CPA evoked a sustained and marked elevation in [Ca(2+)](i) not coupled to contraction. 2-APB (50 microM) inhibited the rise in [Ca(2+)](i) evoked by CPA and the nifedipine-insensitive increases in both [Ca(2+)](i) and contraction elicited by phenylephrine. In alpha-toxin-permeabilized penile arteries, activation of G proteins with guanosine 5'-O-(3-thiotriphosphate) and of the alpha(1)-adrenoceptor with phenylephrine both enhanced the myofilament sensitivity to Ca(2+). This Ca(2+) sensitization was reduced by selective inhibitors of PKC, tyrosine kinase (TK), and Rho kinase (RhoK) by 43%, 67%, and 82%, respectively. As a whole, the present data suggest the alpha(1)-adrenergic vasoconstriction in penile small arteries

  8. Induction of sensitivity to the cytotoxic action of tumor necrosis factor alpha by adenovirus E1A is independent of transformation and transcriptional activation.

    PubMed Central

    Ames, R S; Holskin, B; Mitcho, M; Shalloway, D; Chen, M J

    1990-01-01

    We have previously shown that expression of the adenovirus E1A 12S or 13S products in NIH 3T3 fibroblasts induces susceptibility to the cytotoxic actions of tumor necrosis factor alpha (TNF alpha). A large number of studies have mapped the multiple biological functions of the 12S and 13S products to three highly conserved regions (CR) within the E1A sequence. Here we used plasmids coding for E1A deletion and point mutants in these regions to generate target cell lines for TNF alpha cytotoxicity assays to determine which regions and functions are necessary for the induction of TNF alpha sensitivity. Expression of CR1 was required for the induction of TNF alpha sensitivity. This finding did not reflect a requirement for transforming or transcriptional repression activity, since some mutants that were defective in both of these properties were able to induce TNF alpha sensitivity. CR2 transformation-defective point mutants, but not a CR2/3 region deletion mutant, were also able to induce sensitivity. In addition, NIH 3T3 cells expressing the retroviral transcription activators tat from human immunodeficiency virus type 1 and tax from human T-lymphotropic virus type I were not sensitive to TNF alpha. However, the possibility that E1A-mediated transcriptional activation can augment the induction of TNF alpha sensitivity is not excluded. Comparison of data from previous biological studies with the TNF alpha cytotoxicity assays presented here suggested that the mechanism by which E1A induces sensitivity to TNF alpha in NIH 3T3 cells is independent of many of the known E1A biological functions, including transformation in cooperation with ras, immortalization, induction of DNA synthesis in quiescent cells, and transcriptional repression. A novel E1A-mediated effect may be involved, although our data do not exclude the possibility that sensitization to TNF alpha is mediated through E1A binding to cellular proteins. Images PMID:2143540

  9. Solubilization of a guanyl nucleotide-sensitive alpha/sub 1/ adrenergic receptor from liver membranes

    SciTech Connect

    Harris, S.I.; Moss, J.

    1987-05-01

    Rat liver membranes incubated with norepinephrine before solubilization with digitonin yielded a soluble hormone-receptor complex from which the release of tightly bound norepinephrine was facilitated by guanyl nucleotides. Binding of the alpha/sub 1/-adrenergic receptor antagonist, (/sup 3/H)-prazosin, to the soluble preparation was utilized as a gauge of guanyl nucleotide-induced release of receptor-bound agonist. The following potency series was obtained with regard to the ability of guanyl nucleotides to facilitate (/sup 3/H)-prazosin binding to the solubilized preparation: guanosine 5'-0-(3-thiotriphosphate)(K/sub 1/2/ = 2.5 nM), guanylyl-imidodiphosphate (K/sub 1/2/ = 10 nM), guanosine triphosphate (K/sub 1/2/ = 34 nM) and adenylyl-imidodiphosphate (K/sub 1/2/ > 1 mM). In the presence of guanylyl-imidodiphosphate (0.4 mM), the receptor population displayed monotonic binding parameters with a K/sub d/ for (/sup 3/H)-prazosin of 1.16 nM by Scatchard analysis. Competition curves against (/sup 3/H)-prazosin with the antagonists phentolamine and yohimbine revealed respective K/sub i/'s of .089 ..mu..M and 1.8 ..mu..M; curves with the agonists norepinephrine and isoproterenol yielded respective K/sub i/'s of 6.2..mu..M and 360 ..mu..M. Competition curves performed in the absence of guanyl nucleotide were complex demonstrating an apparent increase in affinity for agonists and an apparent decrease in affinity for antagonists. These curve shifts are consistent with the conversion of receptor to and from the guanyl nucleotide-sensitive state as a function of competing ligand concentration.

  10. Computational prediction of alpha/beta selectivities in the pyrolysis of oxygen-substituted phenethyl phenyl ethers.

    PubMed

    Beste, Ariana; Buchanan, A C; Harrison, Robert J

    2008-06-05

    Phenethyl phenyl ether (PPE; PhCH 2CH 2OPh) is the simplest model for the most common beta-O-4 linkage in lignin. Previously, we developed a computational scheme to calculate the alpha/beta product selectivity in the pyrolysis of PPE by systematically exploiting error cancellation in the computation of relative rate constants. The alpha/beta selectivity is defined as the selectivity between the competitive hydrogen abstraction reaction paths on the alpha- and beta-carbons of PPE. We use density functional theory and employ transition state theory where we include diagonal anharmonic correction in the vibrational partition functions for low frequency modes for which a semiclassical expression is used. In this work we investigate the effect of oxygen substituents (hydroxy, methoxy) in the para position on the phenethyl ring of PPE on the alpha/beta selectivities. The total alpha/beta selectivity increases when substituents are introduced and is larger for the methoxy than the hydroxy substituent. The strongest effect of the substituents is observed for the alpha-pathway of the hydrogen abstraction by the phenoxyl chain carrying radical for which the rate increases. For the beta pathway and the abstraction by the R-benzyl radical (R = OH,OCH 3) the rate decreases with the introduction of the substituents. These findings are compared with results from recent experimental studies.

  11. Sodium selective erythrocyte glycocalyx and salt sensitivity in man.

    PubMed

    Oberleithner, Hans

    2015-06-01

    Negatively charged surfaces of erythrocytes (RBC) reflect properties of the endothelial glycocalyx. Plasma electrolytes counteract these charges and thus control the repulsive forces between RBC and endothelium. Although Na(+) is supposed to exert a rather high affinity to the RBC surface, a direct comparison between Na(+) and K(+) in counteracting the RBC surface has been never made. Therefore, we measured Na(+)/K(+) selectivity of the RBC surface in 20 healthy volunteers applying the previously published salt blood test (SBT). It turned out that the Na(+)/K(+) selectivity ratio of the RBC glycocalyx is on average 6.1 ± 0.39 (ranging from 3 to 9 in different individuals). Considering standard plasma Na(+) and K(+) concentrations, binding probability of Na(+)/K(+) at the RBC surface is about 180:1. The SBT reveals that plasma K(+) counteracts only about 7% of the negative charges in the RBC glycocalyx. As an in vivo proof of principle, a volunteer's blood was continuously tested over 6 months while applying a glycocalyx protective polyphenol-rich natural compound (hawthorn extract). It turned out that RBC Na(+) sensitivity (the inverse of Na(+) buffer capacity) decreased significantly by about 25% while Na(+)/K(+) selectivity of the RBC glycocalyx declined only slightly by about 8 %. Taken together, (i) plasma Na(+) selectively buffers the negative charges of the RBC glycocalyx, (ii) the contribution of K(+) in counteracting these negative surface charges is small, and (iii) natural polyphenols applied in vivo increase RBC surface negativity. In conclusion, low plasma Na(+) is supposed to favor frictionless RBC-slipping through blood vessels.

  12. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading.

    PubMed

    Scharinger, Christian; Kammerer, Yvonne; Gerjets, Peter

    2015-01-01

    Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG) and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading.

  13. Sodium-selective salt sensitivity: its occurrence in blacks.

    PubMed

    Schmidlin, Olga; Forman, Alex; Sebastian, Anthony; Morris, R Curtis

    2007-12-01

    We tested the hypothesis that the Na(+) component of dietary NaCl can have a pressor effect apart from its capacity to complement the extracellular osmotic activity of Cl(-) and, thus, expand plasma volume. We studied 35 mostly normotensive blacks who ingested a low-NaCl diet, 30 mmol/d, for 3 weeks, in the first and third of which Na(+) was loaded orally with either NaHCO(3) or NaCl, in random order (250 mmol/d). In subjects adjudged to be salt sensitive (n=18; Delta mean arterial pressure: >or=5 mm Hg with NaCl load), but not in salt-resistant subjects (n=17), loading with NaHCO(3) was also pressor. The pressor effect of NaHCO(3) was half that of NaCl: mean arterial pressure (millimeters of mercury) increased significantly from 90 on low NaCl to 95 with NaHCO(3) and to 101 with NaCl. The pressor effect of NaCl strongly predicted that of NaHCO(3.) As judged by hematocrit decrease, plasma volume expansion with NaCl was the same in salt-resistant and salt-sensitive subjects and twice that with NaHCO(3), irrespective of the pressor effect. In salt-sensitive subjects, mean arterial pressure varied directly with plasma Na(+) concentration attained with all Na(+) loading. In salt-sensitive but not salt-resistant subjects, NaHCO(3) and NaCl induced decreases in renal blood flow and increases in renal vascular resistance; changes in renal blood flow were not different with the 2 salts. Responses of renal blood flow and renal vascular resistance to NaHCO(3) were strongly predicted by those to NaCl. In establishing the fact of "sodium-selective" salt sensitivity, the current observations demonstrate that the Na(+) component of NaCl can have pressor and renal vasoconstrictive properties apart from its capacity to complement Cl(-) in plasma volume expansion.

  14. Melittin selectively activates capsaicin-sensitive primary afferent fibers.

    PubMed

    Shin, Hong Kee; Kim, Jin Hyuk

    2004-08-06

    Whole bee venom (WBV)-induced pain model has been reported to be very useful for the study of pain. However, the major constituent responsible for the production of pain by WBV is not apparent. Intraplantar injection of WBV and melittin dramatically reduced mechanical threshold, and increased flinchings and paw thickness. In behavioral experiments, capsaicin pretreatment almost completely prevented WBV- and melittin-induced reduction of mechanical threshold and flinchings. Intraplantar injection of melittin increased discharge rate of dorsal horn neurons only with C fiber input from peripheral receptive field, which was completely blocked by topical application of capsaicin to sciatic nerve. These results suggest that both melittin and WBV induce nociceptive responses by selective activation of capsaicin-sensitive afferent fibers.

  15. Selective Alpha-Particle Mediated Depletion of Tumor Vasculature with Vascular Normalization

    PubMed Central

    Seshan, Surya V.; Kappel, Barry J.; Chattopadhyay, Debjit; May, Chad; McDevitt, Michael R.; Nolan, Daniel; Mittal, Vivek; Benezra, Robert; Scheinberg, David A.

    2007-01-01

    Background Abnormal regulation of angiogenesis in tumors results in the formation of vessels that are necessary for tumor growth, but compromised in structure and function. Abnormal tumor vasculature impairs oxygen and drug delivery and results in radiotherapy and chemotherapy resistance, respectively. Alpha particles are extraordinarily potent, short-ranged radiations with geometry uniquely suitable for selectively killing neovasculature. Methodology and Principal Findings Actinium-225 (225Ac)-E4G10, an alpha-emitting antibody construct reactive with the unengaged form of vascular endothelial cadherin, is capable of potent, selective killing of tumor neovascular endothelium and late endothelial progenitors in bone-marrow and blood. No specific normal-tissue uptake of E4G10 was seen by imaging or post-mortem biodistribution studies in mice. In a mouse-model of prostatic carcinoma, 225Ac-E4G10 treatment resulted in inhibition of tumor growth, lower serum prostate specific antigen level and markedly prolonged survival, which was further enhanced by subsequent administration of paclitaxel. Immunohistochemistry revealed lower vessel density and enhanced tumor cell apoptosis in 225Ac-E4G10 treated tumors. Additionally, the residual tumor vasculature appeared normalized as evident by enhanced pericyte coverage following 225Ac-E4G10 therapy. However, no toxicity was observed in vascularized normal organs following 225Ac-E4G10 therapy. Conclusions The data suggest that alpha-particle immunotherapy to neovasculature, alone or in combination with sequential chemotherapy, is an effective approach to cancer therapy. PMID:17342201

  16. The selective inhibition of serpin aggregation by the molecular chaperone, alpha-crystallin, indicates a nucleation-dependent specificity.

    PubMed

    Devlin, Glyn L; Carver, John A; Bottomley, Stephen P

    2003-12-05

    Small heat shock proteins (sHsps) are a ubiquitous family of molecular chaperones that prevent the misfolding and aggregation of proteins. However, specific details about their substrate specificity and mechanism of chaperone action are lacking. alpha1-Antichymotrypsin (ACT) and alpha1-antitrypsin (alpha1-AT) are two closely related members of the serpin superfamily that aggregate through nucleation-dependent and nucleation-independent pathways, respectively. The sHsp alpha-crystallin was unable to prevent the nucleation-independent aggregation of alpha1-AT, whereas alpha-crystallin inhibited ACT aggregation in a dose-dependent manner. This selective inhibition of ACT aggregation coincided with the formation of a stable high molecular weight alpha-crystallin-ACT complex with a stoichiometry of 1 on a molar subunit basis. The kinetics of this interaction occur at the same rate as the loss of ACT monomer, suggesting that the monomeric species is bound by the chaperone. 4,4'-Dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (Bis-ANS) binding and far-UV circular dichroism data suggest that alpha-crystallin interacts specifically with a non-native conformation of ACT. The finding that alpha-crystallin does not interact with alpha1-AT under these conditions suggests that alpha-crystallin displays a specificity for proteins that aggregate through a nucleation-dependent pathway, implying that the dynamic nature of both the chaperone and its substrate protein is a crucial factor in the chaperone action of alpha-crystallin and other sHsps.

  17. Bioinspired nanovalves with selective permeability and pH sensitivity

    NASA Astrophysics Data System (ADS)

    Zheng, Z.; Huang, X.; Schenderlein, M.; Moehwald, H.; Xu, G.-K.; Shchukin, D. G.

    2015-01-01

    Biological systems with controlled permeability and release functionality, which are among the successful examples of living beings to survive in evolution, have attracted intensive investigation and have been mimicked due to their broad spectrum of applications. We present in this work, for the first time, an example of nuclear pore complexes (NPCs)-inspired controlled release system that exhibits on-demand release of angstrom-sized molecules. We do so in a cost-effective way by stabilizing porous cobalt basic carbonates as nanovalves and realizing pH-sensitive release of entrapped subnano cargo. The proof-of-concept work also consists of the establishment of two mathematical models to explain the selective permeability of the nanovalves. Finally, gram-sized (or larger) quantities of the bio-inspired controlled release system can be synthesized through a scaling-up strategy, which opens up opportunities for controlled release of functional molecules in wider practical applications.Biological systems with controlled permeability and release functionality, which are among the successful examples of living beings to survive in evolution, have attracted intensive investigation and have been mimicked due to their broad spectrum of applications. We present in this work, for the first time, an example of nuclear pore complexes (NPCs)-inspired controlled release system that exhibits on-demand release of angstrom-sized molecules. We do so in a cost-effective way by stabilizing porous cobalt basic carbonates as nanovalves and realizing pH-sensitive release of entrapped subnano cargo. The proof-of-concept work also consists of the establishment of two mathematical models to explain the selective permeability of the nanovalves. Finally, gram-sized (or larger) quantities of the bio-inspired controlled release system can be synthesized through a scaling-up strategy, which opens up opportunities for controlled release of functional molecules in wider practical applications

  18. Nuclear estrogen receptor targeted photodynamic therapy: selective uptake and killing of MCF-7 breast cancer cells by a C17alpha-alkynylestradiol-porphyrin conjugate.

    PubMed

    Swamy, Narasimha; Purohit, Ajay; Fernandez-Gacio, Ana; Jones, Graham B; Ray, Rahul

    2006-10-15

    We hypothesized that over-expression of estrogen receptor (ER) in hormone-sensitive breast cancer could be harnessed synergistically with the tumor-migrating effect of porphyrins to selectively deliver estrogen-porphyrin conjugates into breast tumor cells, and preferentially kill the tumor cells upon exposure to red light. In the present work we synthesized four (4) conjugates of C17-alpha-alkynylestradiol and chlorin e6-dimethyl ester with varying tether lengths, and showed that all these conjugates specifically bound to recombinant ER alpha. In a cellular uptake assay with ER-positive MCF-7 and ER-negative MDA-MB 231 human breast cancer cell-lines, we observed that one such conjugate (E17-POR, XIV) was selectively taken up in a dose-dependent and saturable manner by MCF-7 cells, but not by MDA-MB 231 cells. Furthermore, MCF-7 cells, but not MDA-MB 231 cells, were selectively and efficiently killed by exposure to red light after incubation with E17-POR. Therefore, the combination approach, including drug and process modalities has the potential to be applied clinically for hormone-sensitive cancers in organs where ER is significantly expressed. This could potentially be carried out either as monotherapy involving a photo-induced selective destruction of tumor cells and/or adjuvant therapy in post-surgical treatment for the destruction of residual cancer cells in tissues surrounding the tumor.

  19. Alpha-amylase inhibitors selected from a combinatorial library of a cellulose binding domain scaffold.

    PubMed

    Lehtiö, J; Teeri, T T; Nygren, P A

    2000-11-15

    A disulfide bridge-constrained cellulose binding domain (CBD(WT)) derived from the cellobiohydrolase Cel7A from Trichoderma reesei has been investigated for use in scaffold engineering to obtain novel binding proteins. The gene encoding the wild-type 36 aa CBD(WT) domain was first inserted into a phagemid vector and shown to be functionally displayed on M13 filamentous phage as a protein III fusion protein with retained cellulose binding activity. A combinatorial library comprising 46 million variants of the CBD domain was constructed through randomization of 11 positions located at the domain surface and distributed over three separate beta-sheets of the domain. Using the enzyme porcine alpha-amylase (PPA) as target in biopannings, two CBD variants showing selective binding to the enzyme were characterized. Reduction and iodoacetamide blocking of cysteine residues in selected CBD variants resulted in a loss of binding activity, indicating a conformation dependent binding. Interestingly, further studies showed that the selected CBD variants were capable of competing with the binding of the amylase inhibitor acarbose to the enzyme. In addition, the enzyme activity could be partially inhibited by addition of soluble protein, suggesting that the selected CBD variants bind to the active site of the enzyme.

  20. Neonatal oxytocin alters subsequent estrogen receptor alpha protein expression and estrogen sensitivity in the female rat.

    PubMed

    Perry, Adam N; Paramadilok, Auratip; Cushing, Bruce S

    2009-12-14

    In most species, the effects of oxytocin (OT) on female reproductive behavior are dependent upon estrogen, which increases both OT and OT receptor expression. It is also becoming apparent that OT neurotransmission can influence estrogen signaling, especially during development, as neonatal OT manipulations in prairie voles alter ERalpha expression and estrogen-dependent behaviors. We tested the hypothesis that OT developmentally programs ERalpha expression and estrogen sensitivity in female Sprague-Dawley rats, a species previously used to establish the estrogen-dependence of OT signaling in adulthood. OT treatment for the first postnatal week significantly increased ERalpha-immunoreactivity in the ventromedial nucleus of the hypothalamus (VMH), but not in the medial preoptic area (MPOA). Conversely, neonatal OT antagonist (OTA) treatment significantly reduced ERalpha-immunoreactivity in the MPOA, but not in the VMH. Both treatments increased OT-immunoreactivity in the paraventricular nucleus of the hypothalamus (PVN) and reduced estrogen sensitivity, indicated by reduced sexual receptivity following chronic estradiol benzoate (EB) administration. Behavioral deficits in OTA-treated females were apparent during both paced and non-paced tests with 0.5 microg EB (but not 5.0 or 10.0 microg EB), whereas deficits in OT-treated females were only observed during the initial paced test with 0.5 and 5.0 microg EB (but not 10.0 microg EB). The current results demonstrate that OT can positively regulate ERalpha expression within the MPOA and VMH during development; however, endogenous OT selectively programs ERalpha expression within the MPOA. Thus, exogenous OT or OTA exposure during development may have long-term consequences on behavior through stable changes in ERalpha and OT expression.

  1. A cell line with decreased sensitivity to the methyl mercury-induced stimulation of alpha-amanitin sensitive RNA synthesis in isolated nuclei.

    PubMed

    Frenkel, G D; Ducote, J; Reboulleau, C P; Gierthy, J

    1988-01-01

    1. In nuclei isolated from cells of the B50 rat neuroblastoma line the stimulatory effect of methyl mercury on alpha-amanitin-sensitive RNA synthesis is very much reduced compared to the stimulatory effect in HeLa nuclei (see: Frenkel G. D. and Randles K. (1982) Specific stimulation of alpha-amanitin-sensitive RNA synthesis in isolated HeLa nuclei by methyl mercury. J. biol. Chem. 257, 6275-6279). 2. The stimulatory effect of another mercury compound, p-hydroxymercuribenzoate, was also much less pronounced in the B50 nuclei. 3. Similar results were obtained with nuclei isolated from B50 cells which had been induced to differentiate by exposure to dibutaryl cyclic AMP. 4. Nuclei isolated from cells of another rat neuroblastoma line (B35), and nuclei from cells of a human neuroblastoma line both exhibited levels of stimulation similar to that of HeLa nuclei. 5. The B50 and HeLa cells were also compared as to their sensitivity to other effects of methyl mercury.

  2. Selective solid-phase extraction of urinary 2,3-dinor-6-ketoprostaglandin F1 alpha for determination with radioimmunoassay.

    PubMed

    Riutta, A; Nurmi, E; Weber, C; Hansson, G; Vapaatalo, H; Mucha, I

    1994-08-01

    This paper describes a method for selective two-step solid-phase extraction of urinary 2,3-dinor-6-ketoprostaglandin F1 alpha for reliable determination with radioimmunoassay. In the immunoreactivity profile of non-selectively extracted urine after HPLC separation, over 90% of the total 2,3-dinor-6-ketoprostaglandin F1 alpha immunoreactivity consisted of interfering material coeluting with 6-ketoprostaglandin F1 alpha and 2,3-dinor-6-ketoprostaglandin F1 alpha. Among the alkyl silica sorbents studied (methyl, butyl, octyl, and octadecyl), an efficient separation of 2,3-dinor-6-ketoprostaglandin F1 alpha from 6-ketoprostaglandin F1 alpha and the lowest immunoreactive concentration of analyte were achieved in extraction on the methyl silica sorbent by elution of 2,3-dinor-6-ketoprostaglandin F1 alpha with chloroform: hexane (85:15, v/v) from the cartridge. The proportion of specific immunoreactivity could be further increased by two-step extraction of sample on methyl silica cartridges, first at pH 3 and then at pH 10 using diethyl ether:hexane (85:15, v/v) and chloroform as eluent, respectively. After this, a high correlation was found with concentrations of samples determined by radioimmunoassay using three different antisera. A significant correlation of values was also observed between samples measured by radioimmunoassay and those measured by GC-MS. The values of 12-h excretion of 2,3-dinor-6-ketoprostaglandin F1 alpha in eight volunteers (268 +/- 204 ng/g creatinine, mean +/- SD) as well as the inhibitory effect of acetylsalicylic acid (74 +/- 12%) are in accordance with those reported in the literature. This selective extraction procedure provides a high validity in radioimmunoassay without requiring subsequent TLC or HPLC purification.

  3. Parallax-sensitive remapping of visual space in occipito-parietal alpha-band activity during whole-body motion

    PubMed Central

    Selen, L. P. J.; Medendorp, W. P.

    2014-01-01

    Despite the constantly changing retinal image due to eye, head, and body movements, we are able to maintain a stable representation of the visual environment. Various studies on retinal image shifts caused by saccades have suggested that occipital and parietal areas correct for these perturbations by a gaze-centered remapping of the neural image. However, such a uniform, rotational, remapping mechanism cannot work during translations when objects shift on the retina in a more complex, depth-dependent fashion due to motion parallax. Here we tested whether the brain's activity patterns show parallax-sensitive remapping of remembered visual space during whole-body motion. Under continuous recording of electroencephalography (EEG), we passively translated human subjects while they had to remember the location of a world-fixed visual target, briefly presented in front of or behind the eyes' fixation point prior to the motion. Using a psychometric approach we assessed the quality of the memory update, which had to be made based on vestibular feedback and other extraretinal motion cues. All subjects showed a variable amount of parallax-sensitive updating errors, i.e., the direction of the errors depended on the depth of the target relative to fixation. The EEG recordings show a neural correlate of this parallax-sensitive remapping in the alpha-band power at occipito-parietal electrodes. At parietal electrodes, the strength of these alpha-band modulations correlated significantly with updating performance. These results suggest that alpha-band oscillatory activity reflects the time-varying updating of gaze-centered spatial information during parallax-sensitive remapping during whole-body motion. PMID:25505108

  4. Parallax-sensitive remapping of visual space in occipito-parietal alpha-band activity during whole-body motion.

    PubMed

    Gutteling, T P; Selen, L P J; Medendorp, W P

    2015-03-01

    Despite the constantly changing retinal image due to eye, head, and body movements, we are able to maintain a stable representation of the visual environment. Various studies on retinal image shifts caused by saccades have suggested that occipital and parietal areas correct for these perturbations by a gaze-centered remapping of the neural image. However, such a uniform, rotational, remapping mechanism cannot work during translations when objects shift on the retina in a more complex, depth-dependent fashion due to motion parallax. Here we tested whether the brain's activity patterns show parallax-sensitive remapping of remembered visual space during whole-body motion. Under continuous recording of electroencephalography (EEG), we passively translated human subjects while they had to remember the location of a world-fixed visual target, briefly presented in front of or behind the eyes' fixation point prior to the motion. Using a psychometric approach we assessed the quality of the memory update, which had to be made based on vestibular feedback and other extraretinal motion cues. All subjects showed a variable amount of parallax-sensitive updating errors, i.e., the direction of the errors depended on the depth of the target relative to fixation. The EEG recordings show a neural correlate of this parallax-sensitive remapping in the alpha-band power at occipito-parietal electrodes. At parietal electrodes, the strength of these alpha-band modulations correlated significantly with updating performance. These results suggest that alpha-band oscillatory activity reflects the time-varying updating of gaze-centered spatial information during parallax-sensitive remapping during whole-body motion.

  5. BjalphaIT: a novel scorpion alpha-toxin selective for insects--unique pharmacological tool.

    PubMed

    Arnon, Tal; Potikha, Tamara; Sher, Daniel; Elazar, Menashe; Mao, Wenfu; Tal, Tzachy; Bosmans, Frank; Tytgat, Jan; Ben-Arie, Nissim; Zlotkin, Eliahu

    2005-03-01

    Long-chain neurotoxins derived from the venom of the Buthidae scorpions, which affect voltage-gated sodium channels (VGSCs) can be subdivided according to their toxicity to insects into insect-selective excitatory and depressant toxins (beta-toxins) and the alpha-like toxins which affect both mammals and insects. In the present study by the aid of reverse-phase HPLC column chromatography, RT-PCR, cloning and various toxicity assays, a new insect selective toxin designated as BjalphaIT was isolated from the venom of the Judean Black Scorpion (Buthotus judaicus), and its full primary sequence was determined: MNYLVVICFALLLMTVVESGRDAYIADNLNCAYTCGSNSYCNTECTKNGAVSGYCQWLGKYGNACWCINLPDKVPIRIPGACR (leader sequence is underlined). Despite its lack of toxicity to mammals and potent toxicity to insects, BjalphaIT reveals an amino acid sequence and an inferred spatial arrangement that is characteristic of the well-known scorpion alpha-toxins highly toxic to mammals. BjalphaITs sharp distinction between insects and mammals was also revealed by its effect on sodium conductance of two cloned neuronal VGSCs heterloguously expressed in Xenopus laevis oocytes and assayed with the two-electrode voltage-clamp technique. BjalphaIT completely inhibits the inactivation process of the insect para/tipE VGSC at a concentration of 100 nM, in contrast to the rat brain Na(v)1.2/beta1 which is resistant to the toxin. The above categorical distinction between mammal and insect VGSCs exhibited by BjalphaIT enables its employment in the clarification of the molecular basis of the animal group specificity of scorpion venom derived neurotoxic polypeptides and voltage-gated sodium channels.

  6. Immunodominant regions for T helper-cell sensitization on the human nicotinic receptor alpha subunit in myasthenia gravis.

    PubMed Central

    Protti, M P; Manfredi, A A; Straub, C; Howard, J F; Conti-Tronconi, B M

    1990-01-01

    In myasthenia gravis an autoimmune response against the nicotinic acetylcholine receptor (AChR) occurs. The alpha subunit of the AChR contains both the epitope(s) that dominates the antibody response (main immunogenic region) and epitopes involved in T helper cell sensitization. In this study, overlapping synthetic peptides corresponding to the complete AChR alpha-subunit sequence were used to propagate polyclonal AChR-specific T helper cell lines from four myasthenic patients of different HLA types. Response of the T helper lines to the individual peptides was studied. Four immunodominant sequence segments were identified--i.e., residues 48-67, 101-120, 304-322, and 419-437. These regions did not include residues known to form the main immunogenic region or the cholinergic binding site, and they frequently contained sequence motifs that have been proposed to be related to T-epitope formation. Images PMID:2145582

  7. Ocular avirulence of a herpes simplex virus type 1 strain is associated with heightened sensitivity to alpha/beta interferon.

    PubMed Central

    Su, Y H; Oakes, J E; Lausch, R N

    1990-01-01

    BALB/c mice infected on the scarified cornea with herpes simplex virus type 1 strain 35 [HSV-1(35)] rarely developed ocular disease even at challenge doses as high as 10(7) PFU per eye. In contrast, HSV-1(RE) consistently induced stromal keratitis at an inoculum of 2 x 10(4) PFU. The goal of this study was to determine the reason for the difference in virulence between the two HSV strains. Both HSV-1 strains replicated to similar titers in excised corneal "buttons." However, after in vivo infection of the cornea, the growth of strain 35 was evident only during the first 24 h postinfection, whereas the replication of strain RE persisted for at least 4 days. In vitro tests revealed that HSV-1(35) was greater than 10 times more sensitive to alpha/beta interferon (IFN-alpha/beta) than HSV-1(RE). Both strains induced comparable serum levels of IFN after intraperitoneal inoculation. The kinetics of HSV-1(35) clearance from the eye was markedly altered by treatment with rabbit anti-IFN-alpha/beta. Virus titers exceeding 10(4) PFU per eye could be demonstrated 4 to 5 days postinfection in mice given a single inoculation of antiserum 1 h after infection. Furthermore, anti-IFN treatment in 3-week-old mice infected with HSV-1(35) led to the development of clinically apparent corneal disease which subsequently progressed to stromal keratitis in the majority of recipients. These results indicate that the striking difference in the capacity of HSV-1(35) and HSV-1(RE) to induce corneal disease was related to the inherently greater sensitivity of strain 35 to IFN-alpha/beta produced by the host in response to infection. PMID:2157880

  8. A possible structural determinant of selectivity of boldine and derivatives for the alpha 1A-adrenoceptor subtype.

    PubMed Central

    Madrero, Y.; Elorriaga, M.; Martinez, S.; Noguera, M. A.; Cassels, B. K.; D'Ocon, P.; Ivorra, M. D.

    1996-01-01

    1. The selectivity of action of boldine and the related aporphine alkaloids, predicentrine (9-O-methylboldine) and glaucine (2,9-O-dimethylboldine) and alpha 1-adrenoceptor subtypes was studied by examining [3H]-prazosin competition binding in rat cerebral cortex. WB 4101 and benoxathian were used as selective alpha 1A-adrenoceptor antagonists. 2. In the competition experiments [3H]-prazosin (0.2 nM) binding was inhibited by WB 4101 and benoxathian. The inhibition curves displayed shallow slopes which could be subdivided into high and low affinity components (pKi = 9.92 and 8.29 for WB 4101, 9.35 and 7.94 for benoxathian). The two antagonists recognized approximately 37% of the sites with high affinity from among the total [3H]-prazosin specific binding sites. 3. Boldine, predicentrine and glaucine also competed for [3H]-prazosin (0.2 nM) binding with shallow and biphasic curves recognizing 30-40% of the sites with high affinity. Drug affinities (pKi) at the high and low affinity sites were, 8.31 and 6.50, respectively, for boldine, 8.13 and 6.39 for predicentrine, and 7.12 and 5.92 for glaucine. The relative order of selectivity for alpha 1A-adrenoceptors was boldine (70 fold alpha 1A-selective) = predicentrine (60 fold, alpha 1A-selective) > glaucine (15 fold, alpha 1A-selective). 4. Pretreatment of rat cerebral cortex membranes with chloroethylclonidine (CEC, 10 microM) for 30 min at 37 degrees C followed by thorough washing out reduced specific [3H]-prazosin binding by approximately 70%. The CEC-insensitive [3H]-prazosin binding was inhibited by boldine monophasically (Hill slope = 0.93) with a single pKi value (7.76). 5. These results suggest that whereas the aporphine structure shared by these alkaloids is responsible for their selectively of action for the alpha 1A-adrenoceptor subtype in rat cerebral cortex, defined functional groups, namely the 2-hydroxy function, induces a significant increase in alpha 1A-subtype selectivity and affinity. PMID:8982502

  9. Culture, Personality, Health, and Family Dynamics: Cultural Competence in the Selection of Culturally Sensitive Treatments

    ERIC Educational Resources Information Center

    Sperry, Len

    2010-01-01

    Cultural sensitivity and cultural competence in the selection of culturally sensitive treatments is a requisite for effective counseling practice in working with diverse clients and their families, particularly when clients present with health issues or medical problems. Described here is a strategy for selecting culturally sensitive treatments…

  10. NEBULAR ATTENUATION IN H{alpha}-SELECTED STAR-FORMING GALAXIES AT z = 0.8 FROM THE NewH{alpha} SURVEY

    SciTech Connect

    Momcheva, Ivelina G.; Lee, Janice C.; Ouchi, Masami; Ly, Chun; Salim, Samir; Dale, Daniel A.; Finn, Rose; Ono, Yoshiaki

    2013-02-01

    We present measurements of the dust attenuation of H{alpha}-selected emission-line galaxies at z = 0.8 from the NewH{alpha} narrowband survey. The analysis is based on deep follow-up spectroscopy with Magellan/IMACS, which captures the strong rest-frame optical emission lines from [O II] {lambda}3727 to [O III] {lambda}5007. The spectroscopic sample used in this analysis consists of 341 confirmed H{alpha} emitters. We place constraints on the active galactic nucleus (AGN) fraction using diagnostics that can be applied at intermediate redshift. We find that at least 5% of the objects in our spectroscopic sample can be classified as AGNs and 2% are composite, i.e., powered by a combination of star formation and AGN activity. We measure the dust attenuation for individual objects from the ratios of the higher order Balmer lines. The H{beta} and H{gamma} pair of lines is detected with S/N > 5 in 55 individual objects and the H{beta} and H{delta} pair is detected in 50 individual objects. We also create stacked spectra to probe the attenuation in objects without individual detections. The median attenuation at H{alpha} based on the objects with individually detected lines is A(H{alpha}) = 0.9 {+-} 1.0 mag, in good agreement with the attenuation found in local samples of star-forming galaxies. We find that the z = 0.8 galaxies occupy a similar locus of attenuation as a function of magnitude, mass, and star formation rate (SFR) as a comparison sample drawn from the SDSS DR4. Both the results from the individual z = 0.8 galaxies and from the stacked spectra show consistency with the mass-attenuation and SFR-attenuation relations found in the local universe, indicating that these relations are also applicable at intermediate redshift.

  11. Temperature sensitivity of Cu K(alpha) imaging efficiency using a spherical Bragg reflecting crystal

    SciTech Connect

    Akli, K U; Key, M H; Chung, H K; Hansen, S B; Freeman, R R; Chen, M H; Gregori, G; Hatchett, S; Hey, D; Izumi, N; King, J A; Kuba, J; Norreys, P; Mackinnon, A J; Murphy, C D; Snavely, R; Stepehens, R; Stoeckel, C; Theobald, W; Zhang, B

    2006-08-07

    The Vulcan laser facility at the Rutherford Appleton Laboratory was used to study the interaction of a 75 J 10 ps, high intensity laser beam with low-mass solid, Cu targets. Two instruments were fielded as diagnostics of the Cu K-shell emission from the targets: A single photon counting CCD spectrometer provided the absolute K{sub {alpha}} yield and a spherically bent Bragg crystal recorded 2D monochromatic images with a spatial resolution of 10 {micro}m. Due to the shifting and broadening of the K{sub {alpha}} spectral lines with increasing temperature, there is a temperature dependence of the crystal collection efficiency. This provides a temperature diagnostic when cross calibrated against a single hit CCD spectrometer, and it affects measurements of the spatial pattern of electron transport. The experimental data showing changing collection efficiency are presented. The results are discussed in light of modeling of the temperature-dependent spectrum of Cu K-shell emission.

  12. Hyperthermia inhibits platelet haemostatic functions and selectively regulates the release of alpha-granule proteins

    PubMed Central

    Etulain, J; Lapponi, MJ; Patrucchi, SJ; Romaniuk, MA; Benzadón, R; Klement, GL; Negrotto, S; Schattner, M

    2011-01-01

    Summary Background Hyperthermia is one of the main disturbances of homeostasis occurring during sepsis or hypermetabolic states such as cancer. Platelets are important mediators of the inflammation that accompany these processes, but very little is known about the changes in platelet function that occur at different temperatures. Objectives To explore the effect of higher temperatures on platelet physiology. Methods Platelet responses including adhesion, spreading (fluorescence microscopy), αIIbbeta;3 activation (flow cytometry), aggregation (turbidimetry), ATP release (luminescence), thromboxane A2 generation, alpha-granule protein secretion (ELISA), and protein phosphorylation from different signaling pathways (immunoblotting) were studied. Results Preincubation of platelets at temperatures higher than 37°C (38.5°–42°C) inhibited thrombin-induced haemostasis including platelet adhesion, aggregation, ATP release, and thromboxane A2 generation. The expression of P-selectin and CD63, as well as vascular endothelial growth factor (VEGF) release were completely inhibited by hyperthermia, whereas von Willebrand factor (vWF) and endostatin levels remained substantially increased at high temperatures. This suggested that release of proteins from platelet granules is modulated not only by classical platelet agonists but also by microenvironmental factors. The observed gradation of response involved not only antiangiogenesis regulators, but also other cargo proteins. Some signaling pathways were more stable than others. While ERK1/2 and AKT phosphorylation were resistant to changes in temperature, Src, Syk, p38 phosphorylation as well as IkappaB degradation were decreased in a temperature-dependent fashion. Conclusions Higher temperatures, such as those observed with fever or tissue invasion, inhibit the haemostatic functions of platelets and selectively regulate the release of alpha-granule proteins. PMID:21649851

  13. Acidity-controlled selective oxidation of alpha-pinene, isolated from Indonesian pine's turpentine oils (pinus merkusii)

    NASA Astrophysics Data System (ADS)

    Masruri; Farid Rahman, Mohamad; Nurkam Ramadhan, Bagus

    2016-02-01

    Alpha-pinene was isolated in high purity from turpentine oil harvested from Pinus merkusii plantation. The recent investigation on selective oxidation of alpha-pinene using potassium permanganate was undertaken under acidic conditions. The result taught the selective oxidation of alpha-pinene in acidic using potassium permanganate lead to the formation of 2-(3-acetyl-2,2-dimethylcyclobutyl)acetaldehyde or pinon aldehyde. The study method applied reaction in various different buffer conditions i.e. pH 3, 4, 5, and 6, respectively, and each reaction product was monitored using TLC every hour. Product determination was undertaken on spectrometry basis such as infrared, ultra violet-visible, gas chromatography- and liquid chromatography-mass spectrometry.

  14. SSR591813, a novel selective and partial alpha4beta2 nicotinic receptor agonist with potential as an aid to smoking cessation.

    PubMed

    Cohen, C; Bergis, O E; Galli, F; Lochead, A W; Jegham, S; Biton, B; Leonardon, J; Avenet, P; Sgard, F; Besnard, F; Graham, D; Coste, A; Oblin, A; Curet, O; Voltz, C; Gardes, A; Caille, D; Perrault, G; George, P; Soubrie, P; Scatton, B

    2003-07-01

    (5aS,8S,10aR)-5a,6,9,10-Tetrahydro,7H,11H-8,10a-methanopyrido[2',3':5,6]pyrano[2,3-d]azepine (SSR591813) is a novel compound that binds with high affinity to the rat and human alpha4beta2 nicotinic acetylcholine receptor (nAChR) subtypes (Ki = 107 and 36 nM, respectively) and displays selectivity for the alpha4beta2 nAChR (Ki, human alpha3beta4 > 1000, alpha3beta2 = 116; alpha1beta1deltagamma > 6000 nM and rat alpha7 > 6000 nM). Electrophysiological experiments indicate that SSR591813 is a partial agonist at the human alpha4beta2 nAChR subtype (EC50 = 1.3 micro M, IA =19% compared with the full agonist 1,1-dimethyl-4-phenyl-piperazinium). In vivo findings from microdialysis and drug discrimination studies confirm the partial intrinsic activity of SSR591813. The drug increases dopamine release in the nucleus accumbens shell (30 mg/kg i.p.) and generalizes to nicotine or amphetamine (10-20 mg/kg i.p.) in rats, with an efficacy approximately 2-fold lower than that of nicotine. Pretreatment with SSR591813 (10 mg/kg i.p.) reduces the dopamine-releasing and discriminative effects of nicotine. SSR591813 shows activity in animal models of nicotine dependence at doses devoid of unwanted side effects typically observed with nicotine (hypothermia and cardiovascular effects). The compound (10 mg/kg i.p.) also prevents withdrawal signs precipitated by mecamylamine in nicotine-dependent rats and partially blocks the discriminative cue of an acute precipitated withdrawal. SSR591813 (20 mg/kg i.p.) reduces i.v. nicotine self-administration and antagonizes nicotine-induced behavioral sensitization in rats. The present results confirm important role for alpha4beta2 nAChRs in mediating nicotine dependence and suggest that SSR591813, a partial agonist at this particular nAChR subtype, may have therapeutic potential in the clinical management of smoking cessation.

  15. Regulation of semicarbazide-sensitive amine oxidase expression by tumor necrosis factor-alpha in adipocytes: functional consequences on glucose transport.

    PubMed

    Mercier, Nathalie; Moldes, Marthe; El Hadri, Khadija; Fève, Bruno

    2003-03-01

    Membrane-associated semicarbazide-sensitive amine oxidase (SSAO) is mainly present in the media of aorta and in adipose tissue. Recent works have reported that SSAO activation can stimulate glucose transport of fat cells and promote adipose conversion. In this study, the murine 3T3-L1 preadipose cell line was used to investigate SSAO regulation by tumor necrosis factor-alpha (TNF-alpha), a cytokine that is synthesized in fat cells and known to be involved in obesity-linked insulin resistance. SSAO mRNA and protein levels, and enzyme activity were decreased by TNF-alpha in a dose- and time-dependent manner, without any change of SSAO affinity for substrates or inhibitors. SSAO inhibition caused by TNF-alpha was spontaneously reversed along the time after TNF-alpha removal. The decrease in SSAO expression also occurred in white adipose tissue of C57BL/6 mice treated with mTNF-alpha. Overall, we demonstrated that reduction in SSAO expression induced by the cytokine had marked repercussions on amine-stimulated glucose transport, in a dose- and time-dependent manner. This effect was more pronounced than the inhibiting effect of TNF-alpha on insulin-stimulated glucose transport. Moreover, the peroxisome proliferator-activated receptor gamma agonists thiazolidinediones did not reverse either TNF-alpha effect on amine-sensitive glucose transport or the inhibition of SSAO activity, whereas they antagonized TNF-alpha effects on insulin-sensitive glucose transport. These results demonstrate that TNF-alpha can strongly down-regulate SSAO expression and activity, and through this mechanism can dramatically reduce amine-stimulated glucose transport. This suggests a potential role of this regulatory process in the pathogenesis of glucose homeostasis dysregulations observed during diseases accompanied by TNF-alpha overproduction, such as cachexia or obesity.

  16. The alpha7 nicotinic acetylcholine receptor-selective antagonist, methyllycaconitine, partially protects against beta-amyloid1-42 toxicity in primary neuron-enriched cultures.

    PubMed

    Martin, Shelley E; de Fiebre, Nancy Ellen C; de Fiebre, Christopher M

    2004-10-01

    Studies have suggested that the neuroprotective actions of alpha7 nicotinic agonists arise from activation of receptors and not from the extensive desensitization which rapidly follows activation. Here, we report that the alpha7-selective nicotinic antagonist, methyllycaconitine (MLA), protects against beta-amyloid-induced neurotoxicity; whereas the alpha4beta2-selective antagonist, dihydro-beta-erythroidine, does not. These findings suggest that neuroprotective actions of alpha7-acting agents arise from receptor inhibition/desensitization and that alpha7 antagonists may be useful neuroprotective agents.

  17. Category-Specific Visual Responses: An Intracranial Study Comparing Gamma, Beta, Alpha, and ERP Response Selectivity

    PubMed Central

    Vidal, Juan R.; Ossandón, Tomás; Jerbi, Karim; Dalal, Sarang S.; Minotti, Lorella; Ryvlin, Philippe; Kahane, Philippe; Lachaux, Jean-Philippe

    2010-01-01

    The specificity of neural responses to visual objects is a major topic in visual neuroscience. In humans, functional magnetic resonance imaging (fMRI) studies have identified several regions of the occipital and temporal lobe that appear specific to faces, letter strings, scenes, or tools. Direct electrophysiological recordings in the visual cortical areas of epileptic patients have largely confirmed this modular organization, using either single-neuron peri-stimulus time-histogram or intracerebral event-related potentials (iERP). In parallel, a new research stream has emerged using high-frequency gamma-band activity (50–150 Hz) (GBR) and low-frequency alpha/beta activity (8–24 Hz) (ABR) to map functional networks in humans. An obvious question is now whether the functional organization of the visual cortex revealed by fMRI, ERP, GBR, and ABR coincide. We used direct intracerebral recordings in 18 epileptic patients to directly compare GBR, ABR, and ERP elicited by the presentation of seven major visual object categories (faces, scenes, houses, consonants, pseudowords, tools, and animals), in relation to previous fMRI studies. Remarkably both GBR and iERP showed strong category-specificity that was in many cases sufficient to infer stimulus object category from the neural response at single-trial level. However, we also found a strong discrepancy between the selectivity of GBR, ABR, and ERP with less than 10% of spatial overlap between sites eliciting the same category-specificity. Overall, we found that selective neural responses to visual objects were broadly distributed in the brain with a prominent spatial cluster located in the posterior temporal cortex. Moreover, the different neural markers (GBR, ABR, and iERP) that elicit selectivity toward specific visual object categories present little spatial overlap suggesting that the information content of each marker can uniquely characterize high-level visual information in the brain. PMID:21267419

  18. 7alpha,11beta-Dimethyl-19-nortestosterone: a potent and selective androgen response modulator with prostate-sparing properties.

    PubMed

    Cook, C Edgar; Kepler, John A

    2005-02-15

    7alpha,11beta-Dimethyl-19-nortestosterone, made by 1,6-methyl addition to 17beta-acetoxy-11beta-methylestra-4,6-dien-3-one, was a highly potent and selective androgen response modulator, with enhanced androgen receptor binding, androgenic activity and anabolic:androgenic ratio over its two monomethyl homologs.

  19. Selective synthesis of alpha,beta-unsaturated ketones by dibutyltin dimethoxide-catalyzed condensation of aldehydes with alkenyl trichloroacetates.

    PubMed

    Yanagisawa, Akira; Goudu, Riku; Arai, Takayoshi

    2004-11-11

    Various alpha,beta-unsaturated ketones were stereoselectively synthesized in high yields up to 94% by a condensation reaction between alkenyl trichloroacetates and aldehydes using dibutyltin dimethoxide as a catalyst in the presence of methanol. This process is superior to the classical Claisen-Schmidt condensation with respect to mildness of the base catalyst and product selectivity.

  20. Selective perrhenate recognition in pure water by halogen bonding and hydrogen bonding alpha-cyclodextrin based receptors.

    PubMed

    Cornes, Stuart P; Sambrook, Mark R; Beer, Paul D

    2017-03-20

    Alpha-cyclodextrin based anion receptors functionalised with pendant arms containing halogen and hydrogen bond donor motifs display selective association of perrhenate in aqueous media at neutral pH. NMR and ITC anion binding investigations reveal the halogen bonding receptor to be the superior host.

  1. Selective LXR{alpha} inhibitory effects observed in plant extracts of MEH184 (Parthenocissua tricuspidata) and MEH185 (Euscaphis japonica)

    SciTech Connect

    Kim, Kang Ho; Choi, Seung Hyun; Lee, Thomas S.; Oh, Won Keun; Kim, Dong Sun; Kim, Jae Bum . E-mail: jaebkim@snu.ac.kr

    2006-10-20

    Liver X receptors (LXRs) are nuclear hormone receptors that behave as lipid sensors of cellular cholesterol and fatty acid. Although LXR activation can alleviate hypercholesterolemia by inducing cholesterol efflux, it also results in undesirable effects of fatty acid synthesis, resulting in hepatic steatosis and hyperlipidemia. Therefore, it is critical to identify LXR{alpha} inhibitory agents that would repress fatty acid synthesis and hepatic lipid accumulation. In current study, screening of plant extracts used for traditional oriental medicine resulted in the identification of two candidates demonstrating selective LXR{alpha} inhibitory activity. These were whole leaf methanol extracts of Parthenocissua tricuspidata (MEH184) and Euscaphis japonica (MEH185). Both MEH184 and MEH185 decreased transcriptional activity of LXR{alpha} and the expression of LXR{alpha} target genes, such as FAS and ADD1/SREBP1c. Additionally, MEH184 and MEH184 significantly reduced lipogenesis and adipocyte differentiation. Together, the data imply that MEH184 and MEH185 possess selective antagonistic properties on LXR{alpha} to downregulate lipogenesis.

  2. Selecting step sizes in sensitivity analysis by finite differences

    NASA Technical Reports Server (NTRS)

    Iott, J.; Haftka, R. T.; Adelman, H. M.

    1985-01-01

    This paper deals with methods for obtaining near-optimum step sizes for finite difference approximations to first derivatives with particular application to sensitivity analysis. A technique denoted the finite difference (FD) algorithm, previously described in the literature and applicable to one derivative at a time, is extended to the calculation of several simultaneously. Both the original and extended FD algorithms are applied to sensitivity analysis for a data-fitting problem in which derivatives of the coefficients of an interpolation polynomial are calculated with respect to uncertainties in the data. The methods are also applied to sensitivity analysis of the structural response of a finite-element-modeled swept wing. In a previous study, this sensitivity analysis of the swept wing required a time-consuming trial-and-error effort to obtain a suitable step size, but it proved to be a routine application for the extended FD algorithm herein.

  3. Temperature sensitivity of Cu K{sub {alpha}} imaging efficiency using a spherical Bragg reflecting crystal

    SciTech Connect

    Akli, K. U.; Key, M. H.; Chung, H. K.; Hansen, S. B.; Chen, M. H.; Hatchett, S.; Izumi, N.; Mackinnon, A. J.; Snavely, R.; Freeman, R. R.; Gregori, G.; Norreys, P.; Murphy, C. D.; Hey, D.; King, J.; Kuba, J.; Stephens, R. B.; Stoeckel, C.; Theobald, W.; Zhang, B.

    2007-02-15

    The interaction of a 75 J 10 ps, high intensity laser beam with low-mass, solid Cu targets is investigated. Two instruments were fielded as diagnostics of Cu K-shell emission from the targets: a single photon counting spectrometer provided the absolute K{sub {alpha}} yield [C. Stoeckl et al., Rev. Sci. Instrum. 75, 3705 (2004)] and a spherically bent Bragg crystal recorded 2D monochromatic images with a spatial resolution of 10 {mu}m [J. A. Koch et al., Rev. Sci. Instrum. 74, 2130 (2003)]. Due to the shifting and broadening of the K{sub {alpha}} spectral lines with increasing temperature, there is a temperature dependence of the crystal collection efficiency. This affects measurements of the spatial pattern of electron transport, and it provides a temperature diagnostic when cross calibrated against the single photon counting spectrometer. The experimental data showing changing collection efficiency are presented. The results are discussed in light of modeling of the temperature-dependent spectrum of Cu K-shell emission.

  4. Expression of tfx and sensitivity to the rhizobial peptide antibiotic trifolitoxin in a taxonomically distinct group of alpha-proteobacteria including the animal pathogen Brucella abortus.

    PubMed Central

    Triplett, E W; Breil, B T; Splitter, G A

    1994-01-01

    Three phylogenetically distinct groups within the alpha-proteobacteria which differ in trifolitoxin sensitivity are described. Trifolitoxin sensitivity was found in strains of Agrobacterium, Brucella, Mycoplana, Ochrobactrum, Phyllobacterium, Rhodobacter, Rhodopseudomonas, Rhodospirillum, and Rhizobium. Strains of Agrobacterium, Brucella, Phyllobacterium, Rhizobium, and Rhodospirillum were capable of producing trifolitoxin upon conjugal transfer of tfxABCDEFG. PMID:7527627

  5. Cyclosporin A sensitivity of the NF-kappa B site of the IL2R alpha promoter in untransformed murine T cells.

    PubMed Central

    McCaffrey, P G; Kim, P K; Valge-Archer, V E; Sen, R; Rao, A

    1994-01-01

    We have investigated the characteristics of IL2R alpha gene induction in untransformed murine T cells. Induction of IL2R alpha mRNA by TCR/CD3 ligands in a murine T cell clone and in short-term splenic T cell cultures was inhibited by protein synthesis inhibitors and by CsA. This result was contrary to previous observations in JURKAT T leukemia cells and human peripheral blood T cells, suggesting a difference in the mechanisms of IL2R alpha gene induction in these different cell types. The CsA sensitivity of IL2R alpha mRNA induction represented a direct effect on the TCR/CD3 response, and was not due to CsA-sensitive release of the lymphokines IL2 or tumour necrosis factor alpha (TNF alpha) and consequent lymphokine-mediated induction of IL2R alpha mRNA. The NF-kappa B site of the IL2R alpha promoter was essential for gene induction through the TCR/CD3 complex, and the induction of reporter plasmids containing multimers of this site was significantly inhibited by CsA. Northern blotting analysis indicated that while the p65 subunit of NF-kappa B was constitutively expressed and not appreciably induced upon T cell activation, mRNA for the p105 precursor of p50 NF-kappa B was induced in response to TCR/CD3 stimulation and this induction was sensitive to CsA. Electrophoretic mobility shift assays and antiserum against the p50 subunit of NF-kappa B indicated that p50 was a component of the inducible nuclear complex that bound to the IL2R alpha kappa B site. Appearance of the kB-binding proteins was insensitive to CsA at early times after activation (approximately 15 min), but was partially sensitive to CsA at later times. Based on these results, we propose that the NF-kappa B site of the IL2R alpha promoter mediates at least part of the CsA sensitivity of IL2R alpha gene induction in untransformed T cells, possibly because de novo synthesis of p105 NF-kappa B is required for sustained IL2R alpha expression. Images PMID:8029023

  6. Reactivity of the Monoterpenoid Nerol with p-Toluenesulfonic and Chlorosulfonic Acids: Selective Syntheses of alpha-Terpineol and alpha-Cyclogeraniol. An Activity for the Undergraduate Organic Lab

    ERIC Educational Resources Information Center

    Linares-Palomino, Pablo J.; Salido, Sofia; Altarejos, Joaquin; Nogueras, Manuel; Sanchez, Adolfo

    2006-01-01

    The selective syntheses of the cyclic monoterpenoids alpha-terpineol or alpha-cyclogeraniol from the acyclic monoterpenoid nerol using p-toluenesulfonic acid or chlorosulfonic acid as cyclizing agents, respectively, are described. The different behavior of nerol under diverse experimental conditions such as nature of the acid agents, solvents, and…

  7. Variable selection and specification of robust QSAR models from multicollinear data: arylpiperazinyl derivatives with affinity and selectivity for alpha2-adrenoceptors.

    PubMed

    Salt, D W; Maccari, L; Botta, M; Ford, M G

    2004-01-01

    Two QSAR models have been identified that predict the affinity and selectivity of arylpiperazinyl derivatives for alpha1 and alpha2 adrenoceptors (ARs). The models have been specified and validated using 108 compounds whose structures and inhibition constants (Ki) are available in the literature [Barbaro et al., J. Med. Chem., 44 (2001) 2118; Betti et al., J. Med. Chem., 45 (2002) 3603; Barbaro et al., Bioorg. Med. Chem., 10 (2002) 361; Betti et al., J. Med. Chem., 46 (2003) 3555]. One hundred and forty-seven predictors have been calculated using the Cerius 2 software available from Accelrys. This set of variables exhibited redundancy and severe multicollinearity, which had to be identified and removed as appropriate in order to obtain robust regression models free of inflated errors for the beta estimates - so-called bouncing betas. Those predictors that contained information relevant to the alpha2 response were identified on the basis of their pairwise linear correlations with affinity (-log Ki) for alpha2 adrenoceptors; the remaining variables were discarded. Subsequent variable selection made use of Factor Analysis (FA) and Unsupervised Variable Selection (UzFS). The data was divided into test and training sets using cluster analysis. These two sets were characterised by similar and consistent distributions of compounds in a high dimensional, but relevant predictor space. Multiple regression was then used to determine a subset of predictors from which to determine QSAR models for affinity to alpha2-ARs. Two multivariate procedures, Continuum Regression (the Portsmouth formulation) and Canonical Correlation Analysis (CCA), have been used to specify models for affinity and selectivity, respectively. Reasonable predictions were obtained using these in silico screening tools.

  8. Alexa Fluor 546-ArIB[V11L;V16A] is a potent ligand for selectively labeling alpha 7 nicotinic acetylcholine receptors.

    PubMed

    Hone, Arik J; Whiteaker, Paul; Mohn, Jesse L; Jacob, Michele H; McIntosh, J Michael

    2010-08-01

    The alpha7* (*denotes the possible presence of additional subunits) nicotinic acetylcholine receptor (nAChR) subtype is widely expressed in the vertebrate nervous system and implicated in neuropsychiatric disorders that compromise thought and cognition. In this report, we demonstrate that the recently developed fluorescent ligand Cy3-ArIB[V11L;V16A] labels alpha7 nAChRs in cultured hippocampal neurons. However, photobleaching of this ligand during long image acquisition times prompted us to develop a new derivative. In photostability studies, this new ligand, Alexa Fluor 546-ArIB[V11L;V16A], was significantly more resistant to bleaching than the Cy3 derivative. The classic alpha7 ligand alpha-bungarotoxin binds to alpha1* and alpha9* nAChRs. In contrast, Alexa Fluor 546-ArIB[V11L;V16A] potently (IC(50) 1.8 nM) and selectively blocked alpha7 nAChRs but not alpha1* or alpha9* nAChRs expressed in Xenopus oocytes. Selectivity was further confirmed by competition binding studies of native nAChRs in rat brain membranes. The fluorescence properties of Alexa Fluor 546-ArIB[V11L;V16A] were assessed using human embryonic kidney-293 cells stably transfected with nAChRs; labeling was observed on cells expressing alpha7 but not cells expressing alpha3beta2, alpha3beta4, or alpha4beta2 nAChRs. Further imaging studies demonstrate that Alexa Fluor 546-ArIB[V11L;V16A] labels hippocampal neurons from wild-type mice but not from nAChR alpha7 subunit-null mice. Thus, Alexa Fluor 546-ArIB[V11L;V16A] represents a potent and selective ligand for imaging alpha7 nAChRs.

  9. Recombinant interferon-alpha selectively inhibits the production of interleukin-5 by human CD4+ T cells.

    PubMed Central

    Schandené, L; Del Prete, G F; Cogan, E; Stordeur, P; Crusiaux, A; Kennes, B; Romagnani, S; Goldman, M

    1996-01-01

    The effects of recombinant IFN-alpha on the production of IL-5 by human CD4+ T cells were first analyzed on resting CD4+ T cells purified from normal PBMC and stimulated either with a combination of PMA and anti-CD28 mAb or anti-CD3 mAb cross-linked on B7-1/CD32-transfected mouse fibroblasts. We found that IFN-alpha profoundly inhibited in a dose-dependent manner IL-5 production by resting CD4+ T cells whereas IL-10 was upregulated in both systems. The addition of a neutralizing anti-IL-10 mAb to PMA and anti-CD28 mAb upregulated IL-5 production by resting CD4+ T cells but did not prevent IFN-alpha-induced IL-5 inhibition. We then analyzed the effect of IFN-alpha on the production of cytokines by differentiated type 2 helper (Th2) CD4+CD3- cells isolated from peripheral blood of two patients with the hypereosinophilic syndrome. In both cases, IFN-alpha markedly inhibited IL-5 production while it induced mild upregulation of IL-4 and IL-10. Finally, the inhibitory effect of IFN-alpha on IL-5 production was confirmed on a panel of Th2 and Th0 clones generated in vitro. In 2 out of 6 clones, IL-5 inhibition was associated with upregulation of IL-4 and IL-10. We conclude that IFN-alpha selectively downregulates IL-5 synthesis by human CD4+ T cells. PMID:8567949

  10. Overexpression of human alpha-galactosidase A results in its intracellular aggregation, crystallization in lysosomes, and selective secretion

    PubMed Central

    1992-01-01

    Human lysosomal alpha-galactosidase A (alpha-Gal A) was stably overexpressed in CHO cells and its biosynthesis and targeting were investigated. Clone AGA5.3-1000Mx, which was the highest enzyme overexpressor, produced intracellular alpha-Gal A levels of 20,900 U/mg (approximately 100 micrograms of enzyme/10(7) cells) and secreted approximately 13,000 U (or 75 micrograms/10(7) cells) per day. Ultrastructural examination of these cells revealed numerous 0.25-1.5 microns crystalline structures in dilated trans-Golgi network (TGN) and in lysosomes which stained with immunogold particles using affinity- purified anti-human alpha-Gal A antibodies. Pulse-chase studies revealed that approximately 65% of the total enzyme synthesized was secreted, while endogenous CHO lysosomal enzymes were not, indicating that the alpha-Gal A secretion was specific. The recombinant intracellular and secreted enzyme forms were normally processed and phosphorylated; the secreted enzyme had mannose-6-phosphate moieties and bound the immobilized 215-kD mannose-6-phosphate receptor (M6PR). Thus, the overexpressed enzyme's selective secretion did not result from oversaturation of the M6PR-mediated pathway or abnormal binding to the M6PR. Of note, the secreted alpha-Gal A was sulfated and the percent of enzyme sulfation decreased with increasing amplification, presumably due to the inaccessibility of the enzyme's tyrosine residues for the sulfotransferase in the TGN. Overexpression of human lysosomal alpha-N-acetylgalactosaminidase and acid sphingomyelinase in CHO cell lines also resulted in their respective selective secretion. In vitro studies revealed that purified secreted alpha-Gal A was precipitated as a function of enzyme concentration and pH, with 30% of the soluble enzyme being precipitated when 10 mg/ml of enzyme was incubated at pH 5.0. Thus, it is hypothesized that these overexpressed lysosomal enzymes are normally modified until they reach the TGN where the more acidic environment of

  11. Parenteral iron compounds sensitize mice to injury-initiated TNF-alpha mRNA production and TNF-alpha release.

    PubMed

    Zager, Richard A; Johnson, A C M; Hanson, S Y; Lund, Steve

    2005-02-01

    Intravenous Fe is widely used to treat anemia in renal disease patients. However, concerns of potential Fe toxicity exist. To more fully define its spectrum, this study tested Fe's impact on systemic inflammation following either endotoxemia or the induction of direct tissue damage (glycerol-mediated rhabdomyolysis). The inflammatory response was gauged by tissue TNF-alpha message expression and plasma TNF-alpha levels. CD-1 mice received either intravenous Fe sucrose, -gluconate, or -dextran (FeS, FeG, or FeD, respectively; 2 mg), followed by either endotoxin (LPS) or glycerol injection 0-48 h later. Plasma TNF-alpha was assessed by ELISA 2-3 h after the LPS or glycerol challenge. TNF-alpha mRNA expression (RT-PCR) was measured in the kidney, heart, liver, lung, and spleen with Fe +/- LPS treatment. Finally, the relative impacts of intramuscular vs. intravenous Fe and of glutathione (GSH) on Fe/LPS- induced TNF-alpha generation were assessed. Each Fe preparation significantly enhanced LPS- or muscle injury-mediated TNF-alpha generation. This effect was observed for at least 48 h post-Fe injection, a time at which plasma iron levels were increased by levels insufficient to fully saturate transferrin. Fe did not independently increase plasma TNF-alpha or tissue mRNA. However, it potentiated postinjury-induced TNF-alpha mRNA increments and did so in an organ-specific fashion (kidney, heart, and lung; but not in liver or spleen). Intramuscular administration, but not GSH treatment, negated Fe's ability to synergize LPS-mediated TNF-alpha release. We conclude 1) intravenous Fe can enhance TNF-alpha generation during LPS- or glycerol-induced tissue damage; 2) increased TNF-alpha gene transcription in the kidney, heart, and lung may contribute to this result; and 3) intramuscular administration, but not GSH, might potentially mitigate some of Fe's systemic toxic effects.

  12. Selection of the appropriate radionuclide source for the efficiency calibration in methods of determining gross alpha activity in water.

    PubMed

    Corbacho, J A; Zapata-García, D; Montaña, M; Fons, J; Camacho, A; Guillén, J; Serrano, I; Baeza, A; Llauradó, M; Vallés, I

    2016-01-01

    Measuring the gross alpha activity in water samples is a rapid, straightforward way of determining whether the water might contain a radionuclide concentration whose consumption would imply a total indicative dose (TID) greater than some reference limit - currently set at 0.1 mSv/y in Europe. There are several methods used for such measurements. Two of them are desiccation with the salts being deposited on a planchet, and coprecipitation. The main advantage of these two methods is their ease of implementation and low cost of preparing the source to measure. However, there is considerable variability in the selection of the most suitable radioactive reference standard against which to calculate the water's gross alpha activity. The goal of this paper is to propose the most appropriate reference radionuclides to use as standards in determining gross alpha activities with these two methods, taking into account the natural radioactive characteristics of a wide range of waters collected at different points in Spain. Thus, the results will be consistent with each other and representative of the sum of alpha activities of all the alpha-emitters contained in a sample.

  13. Women at altitude: short-term exposure to hypoxia and/or alpha(1)-adrenergic blockade reduces insulin sensitivity.

    PubMed

    Braun, B; Rock, P B; Zamudio, S; Wolfel, G E; Mazzeo, R S; Muza, S R; Fulco, C S; Moore, L G; Butterfield, G E

    2001-08-01

    After short-term exposure to high altitude (HA), men appear to be less sensitive to insulin than at sea level (SL). We hypothesized that the same would be true in women, that reduced insulin sensitivity would be directly related to the rise in plasma epinephrine concentrations at altitude, and that the addition of alpha-adrenergic blockade would potentiate the reduction. To test the hypotheses, 12 women consumed a high-carbohydrate meal at SL and after 16 h at simulated 4,300-m elevation (HA). Subjects were studied twice at each elevation: once with prazosin (Prz), an alpha(1)-adrenergic antagonist, and once with placebo (Pla). Mathematical models were used to assess insulin resistance based on fasting [homeostasis model assessment of insulin resistance (HOMA-IR)] and postprandial [composite model insulin sensitivity index (C-ISI)] glucose and insulin concentrations. Relative to SL-Pla (HOMA-IR: 1.86 +/- 0.35), insulin resistance was greater in HA-Pla (3.00 +/- 0.45; P < 0.05), SL-Prz (3.46 +/- 0.51; P < 0.01), and HA-Prz (2.82 +/- 0.43; P < 0.05). Insulin sensitivity was reduced in HA-Pla (C-ISI: 4.41 +/- 1.03; P < 0.01), SL-Prz (5.73 +/- 1.01; P < 0.05), and HA-Prz (4.18 +/- 0.99; P < 0.01) relative to SL-Pla (8.02 +/- 0.92). Plasma epinephrine was significantly elevated in HA-Pla (0.57 +/- 0.08 ng/ml; P < 0.01), SL-Prz (0.42 +/- 0.07; P < 0.05), and HA-Prz (0.82 +/- 0.07; P < 0.01) relative to SL-Pla (0.28 +/- 0.04), but correlations with HOMA-IR, HOMA-beta-cell function, and C-ISI were weak. In women, short-term exposure to simulated HA reduced insulin sensitivity compared with SL. The change does not appear to be directly mediated by a concurrent rise in plasma epinephrine concentrations.

  14. Estrogen alters the diurnal rhythm of alpha 1-adrenergic receptor densities in selected brain regions

    SciTech Connect

    Weiland, N.G.; Wise, P.M.

    1987-11-01

    Norepinephrine regulates the proestrous and estradiol-induced LH surge by binding to alpha 1-adrenergic receptors. The density of alpha 1-receptors may be regulated by estradiol, photoperiod, and noradrenergic neuronal activity. We wished to determine whether alpha 1-receptors exhibit a diurnal rhythm in ovariectomized and/or estradiol-treated female rats, whether estradiol regulates alpha 1-receptors in those areas of brain involved with LH secretion and/or sexual behavior, and whether the concentrations of alpha-receptors vary inversely relative to previously reported norepinephrine turnover patterns. Young female rats, maintained on a 14:10 light-dark cycle were ovariectomized. One week later, half of them were outfitted sc with Silastic capsules containing estradiol. Groups of animals were decapitated 2 days later at 0300, 1000, 1300, 1500, 1800, and 2300 h. Brains were removed, frozen, and sectioned at 20 micron. Sections were incubated with (/sup 3/H)prazosin in Tris-HCl buffer, washed, dried, and exposed to LKB Ultrofilm. The densities of alpha 1-receptors were quantitated using a computerized image analysis system. In ovariectomized rats, the density of alpha 1-receptors exhibited a diurnal rhythm in the suprachiasmatic nucleus (SCN), medial preoptic nucleus (MPN), and pineal gland. In SCN and MPN, receptor concentrations were lowest during the middle of the day and rose to peak levels at 1800 h. In the pineal gland, the density of alpha 1-receptors was lowest at middark phase, rose to peak levels before lights on, and remained elevated during the day. Estradiol suppressed the density of alpha 1 binding sites in the SCN, MPN, median eminence, ventromedial nucleus, and the pineal gland but had no effect on the lateral septum. Estrogen treatment altered the rhythm of receptor densities in MPN, median eminence, and the pineal gland.

  15. A sensitive and selective assay for chloramine production by myeloperoxidase.

    PubMed

    Dypbukt, Jeannette M; Bishop, Cynthia; Brooks, Wendy M; Thong, Bob; Eriksson, Håkan; Kettle, Anthony J

    2005-12-01

    We describe a new assay for the chlorination activity of myeloperoxidase and detection of chloramines. Chloramines were detected by using iodide to catalyze the oxidation of either 3,3',5,5'-tetramethylbenzidine (TMB) or dihydrorhodamine to form strongly absorbing or fluorescent products, respectively. With TMB as little as 1 muM taurine chloramine could be detected. The sensitivity of the dihydrorhodamine assay was about 10-fold greater. The chlorination activity of myeloperoxidase was measured by trapping hypochlorous acid with taurine and subsequently using iodide to promote the oxidation reactions of the accumulated taurine chloramine. A similar approach was used to detect hypochlorous acid production by stimulated human neutrophils. Iodide-dependent catalysis distinguished N-chloramines from N-bromamines. This allows for discrimination between heme peroxidases that generate either hypochlorous acid or hypobromous acid. The assay has distinct advantages over existing assays for myeloperoxidase with regard to sensitivity, specificity, and its ease and versatility of use.

  16. Selective Vaporization of Superheated Nanodroplets for Rapid, Sensitive, Acoustic Biosensing.

    PubMed

    Chattaraj, Rajarshi; Mohan, Praveena; Besmer, Jeremy D; Goodwin, Andrew P

    2015-08-26

    Superheated perfluorocarbon nano-droplets exhibit promise as sensitive acoustic biosensors. Aggregation of biotin-decorated lipid-shelled droplets by streptavidin greatly increases the yield of bubbles formed by ultrasound-induced vaporization. Streptavidin is sensed down to 1 × 10(-13) m, with differentiable signal appearing in as little as two minutes, using a scalable assay without washing, processing, or development steps.

  17. Effect of ethyl-alpha-hydroxymethylacrylate on selected properties of copolymers and ACP resin composites.

    PubMed

    Antonucci, Joseph M; Fowler, Bruce O; Weir, Michael D; Skrtic, Drago; Stansbury, Jeffrey W

    2008-10-01

    There is an increased interest in the development of bioactive polymeric dental composites and related materials that have potential for mineralized tissue regeneration and preservation. This study explores how the substitution of ethyl alpha-hydroxymethylacryate (EHMA) for 2-hydroxyethyl methacrylate (HEMA) in photo-activated 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA) and Bis-GMA/tri(ethylene glycol) dimethacrylate (TEGDMA) resins affected selected physicochemical properties of the polymers and their amorphous calcium phosphate (ACP) composites. Rate of polymerization and the degree of conversion (DC) of polymers {EHMA (E), HEMA (H), Bis-GMA/EHMA (BE), Bis-GMA/HEMA (BH), Bis-GMA/TEGDMA/EHMA (BTE) and Bis-GMA/TEGDMA/HEMA (BTH)} were assessed by photo-differential scanning calorimetry and Fourier-Transform Infrared (FTIR) spectroscopy. ACP/BTE and ACP/BTH composites were evaluated for DC, biaxial flexure strength (BFS), water sorption (WS) and mineral ion release. Mid-FTIR and near-IR measurements revealed the following order of decreasing DC: [E, H polymers (97.0%)] > [BE copolymer (89.9%)] > [BH copolymer (86.2%)] > [BTE, BTH copolymers (85.5%)] > [ACP/BTH composite (82.6%)] > [ACP/BTE composite (79.3%)]. Compared to HEMA, EHMA did not adversely affect the BFS of its copolymers and/or ACP composites. Lower WS of BTE copolymers and composites (28% and 14%, respectively, compared to the BTH copolymers and composites) only marginal reduced the ion release from ACP/BTE composites compared to ACP/BTH composites. More hydrophobic ACP composites with acceptable ion-releasing properties were developed by substituting the less hydrophilic EHMA for HEMA.

  18. Synapsin Is Selectively Required for Anesthesia-Sensitive Memory

    ERIC Educational Resources Information Center

    Knapek, Stephan; Gerber, Bertram; Tanimoto, Hiromu

    2010-01-01

    Odor-shock memory in "Drosophila melanogaster" consists of heterogeneous components each with different dynamics. We report that a null mutant for the evolutionarily conserved synaptic protein Synapsin entails a memory deficit selectively in early memory, leaving later memory as well as sensory motor function unaffected. Notably, a consolidated…

  19. Environment-sensitive amphiphilic fluorophore for selective sensing of protein.

    PubMed

    Ojha, Bimlesh; Das, Gopal

    2011-04-01

    Here we report the selective sensing of BSA (bovine serum albumin) by 8-(alkoxy)quinoline-based fluorescent probes, via non-covalent interactions. The weak fluorescence of these probes in aqueous solution showed a dramatic increase in quantum yield and lifetime upon binding with BSA, while the responses to various other proteins/enzymes used were negligible under similar experimental conditions. The emission of the probe is affected by the interplay with BSA but not with tryptophan amino acid suggesting that the microenvironment created by the macromolecule induces some change in their excited-state properties. Binding site assignment by a known site-selective binding ligand enabled us to conclude that the compounds predominantly bind at site I of BSA. The changes in fluorescence intensity and the position of emission maxima of compounds in presence of BSA along with the increase in steady state anisotropy values well reflect the nature of binding and location of the probe inside the protein environment. Compounds interact with BSA efficiently and exhibit site selectivity and thus have the potentiality to serve as an efficient and selective sensor of protein.

  20. Correlation of the ionisation response at selected points of IC sensitive regions with SEE sensitivity parameters under pulsed laser irradiation

    NASA Astrophysics Data System (ADS)

    Gordienko, A. V.; Mavritskii, O. B.; Egorov, A. N.; Pechenkin, A. A.; Savchenkov, D. V.

    2014-12-01

    The statistics of the ionisation response amplitude measured at selected points and their surroundings within sensitive regions of integrated circuits (ICs) under focused femtosecond laser irradiation is obtained for samples chosen from large batches of two types of ICs. A correlation between these data and the results of full-chip scanning is found for each type. The criteria for express validation of IC single-event effect (SEE) hardness based on ionisation response measurements at selected points are discussed.

  1. Potent and selective peptide agonists of alpha-melanocyte stimulating hormone (alphaMSH) action at human melanocortin receptor 5; their synthesis and biological evaluation in vitro.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Angeles Cabello, M; Maroto, Marta; Teran, Ana

    2007-05-01

    Melanocortin receptors (MC1-5R) and their endogenous ligands (melanocyte-stimulating hormones and adrenocorticotropic hormone) are involved in many physiological processes in humans. Of those receptors, the actions of MC5R are the least understood despite its broad presence in the numerous peripheral tissues and brain. In this study, we describe synthesis and pharmacological properties in vitro (receptor-binding affinity and agonist activity) of several cyclic analogs of alphaMSH which are potent agonists at hMC5R (EC(50) below 1 nM) and of enhanced receptor subtype selectivity (more than 2000-fold versus hMC1b,3R and about 70- to 200-fold versus hMC4R). These compounds are analogs of Ac-Nle(4)-cyclo[Asp(5)-His(6)-D-Nal(2')(7)-Pip(8)-Trp(9)-Lys(10)]-NH(2) (Pip: pipecolic acid) in which His(6) has been replaced with sterically hindered amino acids. They may be useful tools in the elucidation of the MC5R role in skin disorders and in immunomodulatory and in anti-inflammatory actions of alphaMSH.

  2. Alpha-conotoxin MII-sensitive nicotinic acetylcholine receptors in the nucleus accumbens shell regulate progressive ratio responding maintained by nicotine.

    PubMed

    Brunzell, Darlene H; Boschen, Karen E; Hendrick, Elizabeth S; Beardsley, Patrick M; McIntosh, J Michael

    2010-02-01

    Beta2 subunit containing nicotinic acetylcholine receptors (beta2(*)nAChRs; asterisk ((*)) denotes assembly with other subunits) are critical for nicotine self-administration and nicotine-associated dopamine (DA) release that supports nicotine reinforcement. The alpha6 subunit assembles with beta2 on DA neurons where alpha6beta2(*)nAChRs regulate nicotine-stimulated DA release at neuron terminals. Using local infusion of alpha-conotoxin MII (alpha-CTX MII), an antagonist with selectivity for alpha6beta2(*)nAChRs, the purpose of these experiments was to determine if alpha6beta2(*)nAChRs in the nucleus accumbens (NAc) shell are required for motivation to self-administer nicotine. Long-Evans rats lever-pressed for 0.03 mg/kg, i.v., nicotine accompanied by light+tone cues (NIC) or for light+tone cues unaccompanied by nicotine (CUEonly). Following extensive training, animals were tested under a progressive ratio (PR) schedule that required an increasing number of lever presses for each nicotine infusion and/or cue delivery. Immediately before each PR session, rats received microinfusions of alpha-CTX MII (0, 1, 5, or 10 pmol per side) into the NAc shell or the overlying anterior cingulate cortex. alpha-CTX MII dose dependently decreased break points and number of infusions earned by NIC rats following infusion into the NAc shell but not the anterior cingulate cortex. Concentrations of alpha-CTX MII that were capable of attenuating nicotine self-administration did not disrupt locomotor activity. There was no effect of infusion on lever pressing in CUEonly animals and NAc infusion alpha-CTX MII did not affect locomotor activity in an open field. These data suggest that alpha6beta2(*)nAChRs in the NAc shell regulate motivational aspects of nicotine reinforcement but not nicotine-associated locomotor activation.

  3. Selective gas sensitivity of a microporous barrier-equipped chemoresistor

    NASA Astrophysics Data System (ADS)

    Nemati, Kianoosh; Rahbarpour, Saeedeh

    2011-08-01

    A slab of chemically passive microporous ceramic material is attached to the gas sensitive surface of a chemoresistor. When exposed to analyte contaminated air, analyte molecules diffuse through the slab before affecting the sensor. We compared the transient responses of the barrier-equipped sensor with those of a bare device and resulted in the information regarding the rate process of the analyte's diffusion through the barrier. Rooted in the molecular diffusion equation and the Langmuir model of gas adsorption, a nonlinear partial differential equation was derived to describe the diffusion-physisorption of the analyte in the porous medium. The fitting parameters of the model to the experimental results were utilized as features for analyte identification. These features were used for the classification of different volatile organic substances. Our fabricated sample could recognize methanol, ethanol, 2-propanol and 1-butanol vapors in a wide concentration range in air.

  4. Sensitive And Selective Chemical Sensor With Nanostructured Surfaces.

    DOEpatents

    Pipino, Andrew C. R.

    2003-02-04

    A chemical sensor is provided which includes an optical resonator including a nanostructured surface comprising a plurality of nanoparticles bound to one or more surfaces of the resonator. The nanoparticles provide optical absorption and the sensor further comprises a detector for detecting the optical absorption of the nanoparticles or their environment. In particular, a selective chemical interaction is provided which modifies the optical absorption of the nanoparticles or their environment, and an analyte is detected based on the modified optical absorption. A light pulse is generated which enters the resonator to interrogate the modified optical absorption and the exiting light pulse is detected by the detector.

  5. Diminished neurosteroid sensitivity of synaptic inhibition and altered location of the alpha4 subunit of GABA(A) receptors in an animal model of epilepsy.

    PubMed

    Sun, Chengsan; Mtchedlishvili, Zakaria; Erisir, Alev; Kapur, Jaideep

    2007-11-14

    In animal models of temporal lobe epilepsy (TLE), neurosteroid sensitivity of GABA(A) receptors on dentate granule cells (DGCs) is diminished; the molecular mechanism underlying this phenomenon remains unclear. The current study investigated a mechanism for loss of neurosteroid sensitivity of synaptic GABA(A) receptors in TLE. Synaptic currents recorded from DGCs of epileptic animals (epileptic DGCs) were less frequent, larger in amplitude, and less sensitive to allopregnanolone modulation than those recorded from DGCs of control animals (control DGCs). Synaptic currents recorded from epileptic DGCs were less sensitive to diazepam and had altered sensitivity to benzodiazepine inverse agonist RO 15-4513 (ethyl-8-azido-6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5alpha][1,4]benzodiazepine-3-carboxylate) and furosemide than those recorded from control DGCs. Properties of synaptic currents recorded from epileptic DGCs appeared similar to those of recombinant receptors containing the alpha4 subunit. Expression of the alpha4 subunit and its colocalization with the synaptic marker GAD65 was increased in epileptic DGCs. Location of the alpha4 subunit in relation to symmetric (inhibitory) synapses on soma and dendrites of control and epileptic DGCs was examined with postembedding immunogold electron microscopy. The alpha4 immunogold labeling was present more commonly within the synapse in epileptic DGCs compared with control DGCs, in which the subunit was extrasynaptic. These studies demonstrate that, in epileptic DGCs, the neurosteroid modulation of synaptic currents is diminished and alpha4 subunit-containing receptors are present at synapses and participate in synaptic transmission. These changes may facilitate seizures in epileptic animals.

  6. Characterization of a series of anabaseine-derived compounds reveals that the 3-(4)-dimethylaminocinnamylidine derivative is a selective agonist at neuronal nicotinic alpha 7/125I-alpha-bungarotoxin receptor subtypes.

    PubMed

    de Fiebre, C M; Meyer, E M; Henry, J C; Muraskin, S I; Kem, W R; Papke, R L

    1995-01-01

    Investigation of the naturally occurring, nicotinic agonist anabaseine and novel derivatives has shown that these compounds have cytoprotective and memory-enhancing effects. The hypothesis that these arise at least in part through actions on brain nicotinic receptors was evaluated by examining the ability of these compounds to displace the binding of nicotinic ligands and to affect the function of the alpha 4 beta 2 and alpha 7 receptor subtypes expressed in Xenopus oocytes. The derivative 3-(4)-dimethylaminocinnamylidine anabaseine (DMAC) was found to be a selective alpha 7 receptor agonist; it was more potent than nicotine, acetylcholine, anabaseine, and other derivatives at activating the alpha 7 receptor subtype, while displaying little agonist activity at alpha 4 beta 2 and other receptor subtypes. Compared with anabaseine and the other derivatives, DMAC was the most potent at displacing 125I-alpha-bungarotoxin binding (putative alpha 7) and the least potent at displacing [3H]cytisine binding (putative alpha 4 beta 2) to brain membranes. Independently of agonist activities, all of the novel compounds displayed secondary inhibitory activity at both receptor subtypes. At the alpha 4 beta 2 receptor subtype, inhibition by the 3-(2,4)-dimethoxybenzylidene derivative was enhanced by coapplication of acetylcholine, suggesting a noncompetitive form of inhibition. Anabaseine and nicotine prolonged the time course of activation of alpha 4 beta 2 receptors, compared with acetylcholine, suggesting sequential channel-blocking activity. As selective agonists, anabaseine derivatives such as DMAC may be useful for elucidating the function of alpha 7 nicotinic receptors, including their potential role(s) in the cytoprotective and memory-enhancing effects of nicotinic agents.

  7. Co-receptor choice by V alpha14i NKT cells is driven by Th-POK expression rather than avoidance of CD8-mediated negative selection.

    PubMed

    Engel, Isaac; Hammond, Kirsten; Sullivan, Barbara A; He, Xi; Taniuchi, Ichiro; Kappes, Dietmar; Kronenberg, Mitchell

    2010-05-10

    Mouse natural killer T (NKT) cells with an invariant V alpha14-J alpha18 rearrangement (V alpha14 invariant [V alpha14i] NKT cells) are either CD4(+)CD8(-) or CD4(-)CD8(-). Because transgenic mice with forced CD8 expression in all T cells exhibited a profound NKT cell deficit, the absence of CD8 has been attributed to negative selection. We now present evidence that CD8 does not serve as a coreceptor for CD1d recognition and that the defect in development in CD8 transgene homozygous mice is the result of a reduction in secondary T cell receptor alpha rearrangements. Thymocytes from mice hemizygous for the CD8 transgene have a less severe rearrangement defect and have functional CD8(+) V alpha14i NKT cells. Furthermore, we demonstrate that the transcription factor Th, Poxviruses and Zinc finger, and Krüppel family (Th-POK) is expressed by V alpha14i NKT cells throughout their differentiation and is necessary both to silence CD8 expression and for the functional maturity of V alpha14i NKT cells. We therefore suggest that Th-POK expression is required for the normal development of V alpha14i NKT cells and that the absence of CD8 expression by these cells is a by-product of such expression, as opposed to the result of negative selection of CD8-expressing V alpha14i NKT cells.

  8. Short-term selection for acute ethanol tolerance and sensitization from an F2 population derived from the high and low alcohol-sensitive selectively bred rat lines.

    PubMed

    Radcliffe, Richard A; Bludeau, Pequita; Deng, Xin-Sheng; Erwin, V Gene; Deitrich, Richard A

    2007-12-01

    Previous studies have identified quantitative trait loci (QTL) in the inbred high and low alcohol-sensitive rat (IHAS1 and ILAS1) strains. The original development of the strains involved selection for ethanol sensitivity based on duration of the loss of the righting reflex (LORR) after a standard dose of ethanol. This paper confirms some of these QTL using a short-term selection procedure based on the difference between the blood ethanol level at LORR and regain of the righting response. An F(2) population of rats was developed by a reciprocal cross of IHAS1 and ILAS1 rats. Selection for five generations was carried out using delta-blood ethanol concentration (dBEC) as the selection trait, where dBEC=BECLR (BEC at loss of righting reflex)-BECRR (BEC at regain of righting reflex). The lines were labeled tolerant (TOL) or sensitive (SENS). Approximately one-third of the offspring for each generation in each line were genotyped using DNA markers that had been previously found to be linked to QTL on chromosomes 1, 2, 5, 12, and 13. By the fifth generation of selection, the lines showed a very large difference in dBEC, BECRR, and duration of LORR; BECLR showed little segregation during the selection, and latency to lose the righting reflex showed none. IHAS allele frequency increased in the SENS line for markers on chromosomes 1, 5, 12, and 13 while ILAS allele frequency increased in the TOL line. These results were in good agreement with the two previous QTL studies. On chromosome 2, the selection resulted in an accumulation of ILAS alleles in both lines. This study provides independent confirmation of the location of QTL on chromosomes 1, 5, 12, and 13 for ethanol sensitivity. It also suggests that genetic differences in duration of LORR are mediated primarily by the dBEC phenotype.

  9. The characterization of a novel rigid nicotine analog with alpha7-selective nAChR agonist activity and modulation of agonist properties by boron inclusion.

    PubMed

    Papke, Roger L; Zheng, Guangrong; Horenstein, Nicole A; Dwoskin, Linda P; Crooks, Peter A

    2005-09-01

    The alpha7 nAChR subtype is of particular interest as a potential therapeutic target since it has been implicated as a mediator of both cognitive and neuroprotective activity. The rigid nicotine analog ACME and the N-cyanoborane conjugate ACME-B are selective partial agonists of rat alpha7 receptors expressed in Xenopus oocytes, with no significant activation of either alpha3beta4 or alpha4beta2 receptors. ACME-B is both more potent and efficacious than ACME. The efficacies of ACME-B and ACME are approximately 26% and 10% of the efficacy of ACh, respectively. Similar N-conjugation of S(-)nicotine with cyanoborane decreased efficacy for alpha3beta4 and alpha4beta2 receptors, as well as for alpha7 nAChR. Structural comparison of ACME with the benzylidene anabaseines, another class of previously identified alpha7-selective agonists, suggests that they share a similar structural motif that may be applicable to other alpha7-selective agonists.

  10. Alpha 1-adrenergic agonists selectively suppress voltage-dependent K+ current in rat ventricular myocytes.

    PubMed Central

    Apkon, M; Nerbonne, J M

    1988-01-01

    The effects of alpha 1-adrenergic agonists on the waveforms of action potentials and voltage-gated ionic currents were examined in isolated adult rat ventricular myocytes by the whole-cell patch-clamp recording technique. After "puffer" applications of either of two alpha 1 agonists, phenylephrine and methoxamine, action-potential durations were increased. In voltage-clamped cells, phenylephrine (5-20 microM) or methoxamine (5-10 microM) reduced the amplitudes of Ca2+-independent voltage-activated outward K+ currents (Iout); neither the kinetics nor the voltage-dependent properties of Iout were significantly affected. The effects of phenylephrine or methoxamine on Iout were larger and longer-lasting at higher concentrations and after prolonged or repeated exposures; in all experiments, however, Iout recovered completely when puffer applications were discontinued. The suppression of Iout is attributed to the activation of alpha 1-adrenergic receptors, as neither beta- nor alpha 2-adrenergic agonists had measurable effects on Iout; in addition, the effect of phenylephrine was attenuated in the presence of the alpha antagonist phentolamine (10 microM), but not in the presence of the beta antagonist propranolol (10 microM). Voltage-gated Ca2+ currents, in contrast, were not altered measurably by phenylephrine or methoxamine and no currents were activated directly by these agents. Suppression of Iout was also observed during puffer applications of either of two protein kinase C activators, phorbol 12-myristate 13-acetate (10 nM-1 microM) and 1-oleoyl-2-acetylglycerol (60 microM). We conclude that the activation of alpha 1-adrenergic receptors in adult rat ventricular myocytes leads to action-potential prolongation as a result of the specific suppression of Iout and that this effect may be mediated by activation of protein kinase C. PMID:2903506

  11. The AMP-activated protein kinase alpha2 catalytic subunit controls whole-body insulin sensitivity.

    PubMed

    Viollet, Benoit; Andreelli, Fabrizio; Jørgensen, Sebastian B; Perrin, Christophe; Geloen, Alain; Flamez, Daisy; Mu, James; Lenzner, Claudia; Baud, Olivier; Bennoun, Myriam; Gomas, Emmanuel; Nicolas, Gaël; Wojtaszewski, Jørgen F P; Kahn, Axel; Carling, David; Schuit, Frans C; Birnbaum, Morris J; Richter, Erik A; Burcelin, Rémy; Vaulont, Sophie

    2003-01-01

    AMP-activated protein kinase (AMPK) is viewed as a fuel sensor for glucose and lipid metabolism. To better understand the physiological role of AMPK, we generated a knockout mouse model in which the AMPKalpha2 catalytic subunit gene was inactivated. AMPKalpha2(-/-) mice presented high glucose levels in the fed period and during an oral glucose challenge associated with low insulin plasma levels. However, in isolated AMPKalpha2(-/-) pancreatic islets, glucose- and L-arginine-stimulated insulin secretion were not affected. AMPKalpha2(-/-) mice have reduced insulin-stimulated whole-body glucose utilization and muscle glycogen synthesis rates assessed in vivo by the hyperinsulinemic euglycemic clamp technique. Surprisingly, both parameters were not altered in mice expressing a dominant-negative mutant of AMPK in skeletal muscle. Furthermore, glucose transport was normal in incubated isolated AMPKalpha2(-/-) muscles. These data indicate that AMPKalpha2 in tissues other than skeletal muscles regulates insulin action. Concordantly, we found an increased daily urinary catecholamine excretion in AMPKalpha2(-/-) mice, suggesting altered function of the autonomic nervous system that could explain both the impaired insulin secretion and insulin sensitivity observed in vivo. Therefore, extramuscular AMPKalpha2 catalytic subunit is important for whole-body insulin action in vivo, probably through modulation of sympathetic nervous activity.

  12. Sensitivity of Alpha and Beta Oscillations to Sensorimotor Characteristics of Action: An EEG Study of Action Production and Gesture Observation

    PubMed Central

    Quandt, Lorna C.; Marshall, Peter J.; Shipley, Thomas F.; Beilock, Sian L.; Goldin-Meadow, Susan

    2012-01-01

    The sensorimotor experiences we gain when performing an action have been found to influence how our own motor systems are activated when we observe others performing that same action. Here we asked whether this phenomenon applies to the observation of gesture. Would the sensorimotor experiences we gain when performing an action on an object influence activation in our own motor systems when we observe others performing a gesture for that object? Participants were given sensorimotor experience with objects that varied in weight, and then observed video clips of an actor producing gestures for those objects. Electroencephalography (EEG) was recorded while participants first observed either an iconic gesture (pantomiming lifting an object) or a deictic gesture (pointing to an object) for an object, and then grasped and lifted the object indicated by the gesture. We analyzed EEG during gesture observation to determine whether oscillatory activity was affected by the observer’s sensorimotor experiences with the object represented in the gesture. Seeing a gesture for an object previously experienced as light was associated with a suppression of power in alpha and beta frequency bands, particularly at posterior electrodes. A similar pattern was found when participants lifted the light object, but over more diffuse electrodes. Moreover, alpha and beta bands at right parieto-occipital electrodes were sensitive to the type of gesture observed (iconic vs. deictic). These results demonstrate that sensorimotor experience with an object affects how a gesture for that object is processed, as measured by the gesture-observer’s EEG, and suggest that different types of gestures recruit the observer’s own motor system in different ways. PMID:22910276

  13. Selectivity of fungal sesquiterpene synthases: role of the active site's H-1 alpha loop in catalysis.

    PubMed

    López-Gallego, Fernando; Wawrzyn, Grayson T; Schmidt-Dannert, Claudia

    2010-12-01

    Sesquiterpene synthases are responsible for the cyclization of farnesyl pyrophosphate into a myriad of structurally diverse compounds with various biological activities. We examine here the role of the conserved active site H-α1 loop in catalysis in three previously characterized fungal sesquiterpene synthases. The H-α1 loops of Cop3, Cop4, and Cop6 from Coprinus cinereus were altered by site-directed mutagenesis and the resultant product profiles were analyzed by gas chromatography-mass spectrometry and compared to the wild-type enzymes. In addition, we examine the effect of swapping the H-α1 loop from the promiscuous enzyme Cop4 with the more selective Cop6 and the effect of acidic or basic conditions on loop mutations in Cop4. Directed mutations of the H-α1 loop had a marked effect on the product profile of Cop3 and Cop4, while little to no change was shown in Cop6. Swapping of the Cop4 and Cop6 loops with one another was again shown to influence the product profile of Cop4, while the product profile of Cop6 remained identical to the wild-type enzyme. The loop mutations in Cop4 also implicate specific residues responsible for the pH sensitivity of the enzyme. These results affirm the role of the H-α1 loop in catalysis and provide a potential target to increase the product diversity of terpene synthases.

  14. Combination of interferon alpha with either Ara-C or ATRA in vitro reduces the selective action of interferon against CML CFU-GM.

    PubMed

    Marley, S B; Davidson, R J; Goldman, J M; Gordon, M Y

    2000-08-01

    Although interferon (IFN)-alpha has no specific inhibitory effect on the plating efficiency of granulocyte-macrophage colony-forming cells (CFU-GM) from patients with chronic myeloid leukaemia (CML), it does selectively inhibit the replating ability (secondary colony formation) of CML CFU-GM. Thus, amplification of CFU-GM may be a target for IFN-alpha and other agents used in the treatment of CML. Here we examined whether cytarabine (Ara-C) or all-trans retinoic acid (ATRA) exert similar effects and whether they might in combination with IFN-alpha enhance its efficacy. We found that Ara-C preferentially inhibits the formation of CML CFU-GM compared to normal CFU-GM, but this inhibition was not increased by addition of IFN-alpha. When Ara-C was added to cultures containing IFN-alpha, the inhibition of replating by CML progenitors was abrogated. ATRA increased significantly the plating efficiency of normal CFU-GM. The addition of IFN-alpha to ATRA had no effect on CML or normal colony numbers. However, addition of ATRA to cultures containing IFN-alpha reversed the selective inhibition of CML CFU-GM replating seen in cultures containing IFN-alpha alone. In four IFN-alpha/Ara-C experiments, secondary CML patient-derived colonies were examined by fluorescence in situ hybridisation (FISH). All of them were Ph chromosome positive. No significant effects on CFU-GM production were observed when CML primitive haemopoietic progenitor cells were investigated in a delta (delta) assay. Thus we conclude that combining IFN-alpha with Ara-C or ATRA neutralises the effect of IFN-alpha on CML CFU-GM. This observation provides a rationale for treating patients with alternating courses of IFN-alpha and Ara-C or ATRA, rather than giving either of these two agents in combination with IFN-alpha.

  15. Organocatalytic C3-selective Friedel-Crafts alkylations of indoles with alpha,beta-unsaturated ketones.

    PubMed

    Li, Dong-Ping; Guo, Ying-Cen; Ding, Yu; Xiao, Wen-Jing

    2006-02-21

    The use of an equimolar amount of pyrrolidine and HClO4 (30 mol%) was found to be effective in promoting the conjugate addition of indoles to (E)-alpha,beta-unsaturated ketones, affording the corresponding beta-indolyl ketones in excellent yields.

  16. Polarization Calibration of the Chromospheric Lyman-Alpha SpectroPolarimeter for a 0.1 % Polarization Sensitivity in the VUV Range. Part I: Pre-flight Calibration

    NASA Astrophysics Data System (ADS)

    Giono, G.; Ishikawa, R.; Narukage, N.; Kano, R.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.; Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.

    2016-12-01

    The Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) is a sounding rocket experiment designed to measure for the first time the linear polarization of the hydrogen Lyman-{α} line (121.6 nm) and requires a 0.1 % polarization sensitivity, which is unprecedented for a spectropolarimeter in the vacuum UV (VUV) spectral range.

  17. Selective production of alpha olefins from synthesis gas over ZnO supported Pd-Fe bimetallics

    SciTech Connect

    Gustafson, B.L.; Wehner, P.S.

    1986-01-01

    Olefins are basic raw materials for a wide variety of commercial processes within the chemical industry. A synthesis-gas-based route to low molecular weight ..cap alpha..-olefins would provide the chemical industry with an alternative route to raw materials in the advent of future petroleum shortages or price increases. The catalytic production of ..cap alpha..-olefins from synthesis gas has been the subject of many investigations over the past 50 years. It has been established that, in some systems, olefin selectivity can be enhanced through the addition of various promoters such as K, Mn, Ti, or Zn. Olefin selectivity can also be dependent on process parameters such as temperature, pressure, conversion levels, or feed compositions. Recent reports in the literature indicate that supported Fe-containing bimetallics may also be selective for the production of olefins from synthesis gas. This study reports the use of Pd-FE bimetallics supported on ZnO for the selective production of olefins from synthesis gas.

  18. Design of beta-domain swapping, alpha/beta-protein, environmentally sensitive coiled coil and peptide functionalized titania materials

    NASA Astrophysics Data System (ADS)

    Nagarkar, Radhika P.

    2009-12-01

    The objective of this dissertation is to apply rational peptide design to fabricate nanomaterials via self-assembly. This has been demonstrated in structurally diverse systems with an aim of deciphering the underlying principles governing how sequence affects the peptide's ability to adopt a specific secondary structure and ultimate material properties that are realized from the association of these secondary structural elements. Several amyloidogenic proteins have been shown to self-assemble into fibrils using a mechanism known as domain swapping. Here, discreet units of secondary structure are exchanged among discreet proteins during self-assembly to form extended networks with precise three dimensional organization. The possibility of using these mechanisms to design peptides capable of controlled assembly and fibril formation leading to materials with targeted properties is explored. By altering the placement of a beta-turn sequence that varies the size and location of the exchanged strand, twisting, non-twisting and laminated fibrillar nanostructures are obtained. Hydrogels prepared from these strand swapping beta-hairpins have varied rheological properties due to differences in their fibrillar nanostructures. In a second distinct design, alpha/beta-proteins are used to prepare environmentally sensitive hydrogels. Here, multiple distinct motifs for structural integrity and dynamic response within a single self-assembling peptide allow the amyloid-like fibrils formed to controllably alter their nano-topography in response to an external stimulus such as temperature. The development of these self-assembling alpha/beta-protein motifs also necessitated the design of pH sensitive antiparallel coiled coils. Exploring the basic principles responsible for pH dependent conformational changes in coiled coils can lead to new insights in the control of protein structure and function. Lastly, this dissertation discusses the interface between biomolecules and inorganic

  19. Affinity purification of the voltage-sensitive sodium channel from electroplax with resins selective for sialic acid

    SciTech Connect

    James, W.M.; Emerick, M.C.; Agnew, W.S. )

    1989-07-11

    The voltage-sensitive sodium channel present in the eel (Electrophorus electricus) has an unusually high content of sialic acid, including {alpha}-(2{yields}8)-linked polysialic acid, not found in other electroplax membrane glycopeptides. Lectins from Limax flavus (LFA) and wheat germ (WGA) proved the most effective of 11 lectin resins tried. The most selective resin was prepared from IgM antibodies against Neisseria meningitidis {alpha}-(2{yields}8)-polysialic acid which were affinity purified and coupled to Sepharose 4B. The sodium channel was found to bind to WGA, LFA, and IgM resins and was readily eluted with the appropriate soluble carbohydrates. Experiments with LFA and IgM resins demonstrated binding and unbinding rates and displacement kinetics, which suggest highly specific binding at multiple sites on the sodium channel protein. In preparative-scale purification of protein previously fractionated by anion-exchange chromatography, without stabilizing TTX, high yields were reproducibly obtained. Further, when detergent extracts were prepared from electroplax membranes fractionated by low-speed sedimentation, a single step over the IgM resin provided a 70-fold purification, yielding specific activities of 3,200 pmol of ({sup 3}H)TTX-binding sites/mg of protein and a single polypeptide of {approximately}285,000 Da on SDS-acrylamide gels. No small peptides were observed after this 5-h isolation. The authors describe a cation-dependent stabilization with millimolar levels of monovalent and micromolar levels of divalent species.

  20. Affinity purification of the voltage-sensitive sodium channel from electroplax with resins selective for sialic acid.

    PubMed

    James, W M; Emerick, M C; Agnew, W S

    1989-07-11

    The voltage-sensitive sodium channel present in the eel (Electrophorus electricus) has an unusually high content of sialic acid, including alpha-(2----8)-linked polysialic acid, not found in other electroplax membrane glycopeptides. Lectins from Limax flavus (LFA) and wheat germ (WGA) proved the most effective of 11 lectin resins tried. The most selective resin was prepared from IgM antibodies against Neisseria meningitidis alpha-(2----8)-polysialic acid which were affinity purified and coupled to Sepharose 4B. The sodium channel was found to bind to WGA, LFA, and IgM resins and was readily eluted with the appropriate soluble carbohydrates. Experiments with LFA and IgM resins demonstrated binding and unbinding rates and displacement kinetics, which suggest highly specific binding at multiple sites on the sodium channel protein. In preparative-scale purification of protein previously fractionated by anion-exchange chromatography, without stabilizing TTX, high yields were reproducibly obtained. Further, when detergent extracts were prepared from electroplax membranes fractionated by low-speed sedimentation, a single step over the IgM resin provided a 70-fold purification, yielding specific activities of 3200 pmol of [3H]TTX-binding sites/mg of protein and a single polypeptide of approximately 285,000 Da on SDS-acrylamide gels. No small peptides were observed after this 5-h isolation. We further describe a cation-dependent stabilization with millimolar levels of monovalent and micromolar levels of divalent species.

  1. Correlation of the ionisation response at selected points of IC sensitive regions with SEE sensitivity parameters under pulsed laser irradiation

    SciTech Connect

    Gordienko, A V; Mavritskii, O B; Egorov, A N; Pechenkin, A A; Savchenkov, D V

    2014-12-31

    The statistics of the ionisation response amplitude measured at selected points and their surroundings within sensitive regions of integrated circuits (ICs) under focused femtosecond laser irradiation is obtained for samples chosen from large batches of two types of ICs. A correlation between these data and the results of full-chip scanning is found for each type. The criteria for express validation of IC single-event effect (SEE) hardness based on ionisation response measurements at selected points are discussed. (laser applications and other topics in quantum electronics)

  2. The selectivity filter of the tandem pore potassium channel TASK-1 and its pH-sensitivity and ionic selectivity.

    PubMed

    Yuill, K; Ashmole, I; Stanfield, P R

    2004-04-01

    We have studied pH sensitivity and ionic selectivity of the tandem pore K(+) channel TASK-1 heterologously expressed in Xenopus oocytes. We fit pH sensitivity assuming that only one of the two residues H98 need be protonated for channels to be shut. The effect of protons was weakly voltage dependent with a p K(a) of 6.02 at +40 mV. Replacement of His (H98D, H98N) reduced pH sensitivity but did not abolish it. Use of a concatameric channel permitted replacement of one His residue only; this concatamer was fully pH-sensitive. Increasing the number of His residues to 4 (mutant D204H) abolished pH sensitivity over the physiological range. The implication that D204 plays a role in pH-sensitivity was confirmed by the finding that pH sensitivity over the physiological range was also abolished in the mutant D204N. Ionic selectivity was also altered in D204H, D204N and H98D mutants. P(Rb)/ P(K) was increased from 0.80+/-0.04 (n=19) in wild type to 1.06+/-0.04 (n=19) in D204H. H98D, D204H and D204N were permeable to Na(+) with P(Na)/ P(K)=0.39+/-0.03 (n=14) in H98D, 0.64+/-0.04 (n=18) in D204H and 0.33+/-0.07 (n=3) in D204N. Thus, the arrangement of ring of residues HDHD appears to optimise both pH sensitivity and ionic selectivity.

  3. Highly sensitive and selective gold(I) recognition by a metalloregulator in Ralstonia metallidurans.

    PubMed

    Jian, Xing; Wasinger, Erik C; Lockard, Jenny V; Chen, Lin X; He, Chuan

    2009-08-12

    A MerR family metalloregulatory protein CupR selectively responds to gold stress in Ralstonia metallidurans. A distorted trigonal geometry appears to be used by CupR to achieve the highly sensitive (K(d) approximately 10(-35) M) and selective recognition of gold(I).

  4. Selective inhibition of histidine-modified pancreatic alpha-amylase by proteinaceous inhibitor from Phaseolus vulgaris.

    PubMed

    Nakatani, H

    1988-06-01

    Chemical modification of two histidine residues of porcine pancreatic alpha-amylase (EC 3.2.1.1) by diethyl pyrocarbonate in the presence of a high concentration of maltotriose caused a decrease of amylase activity and an increase of maltosidase activity (hydrolysis of p-nitrophenyl-alpha-maltoside). By binding a proteinaceous inhibitor from Phaseolus vulgaris (white kidney bean) with the modified enzyme, the amylase activity was further decreased but the maltosidase activity was retained to about 100% that of the native enzyme. Both amylase and maltosidase activities of the native enzyme were almost completely inhibited by the proteinaceous inhibitor. The increase of maltosidase activity by histidine modification was due to an increase of kcat, whereas the Km value was not changed; but binding of the proteinous inhibitor affected mainly the Km value of the modified enzyme.

  5. Horseradish peroxidase functionalized gold nanorods as a label for sensitive electrochemical detection of alpha-fetoprotein antigen.

    PubMed

    Guo, Jinjin; Han, Xiaowei; Wang, Junchun; Zhao, Junqing; Guo, Zilin; Zhang, Yuzhong

    2015-12-15

    In this study, a novel tracer, horseradish peroxidase (HRP) functionalized gold nanorods (Au NRs) nanocomposites (HRP-Au NRs), was designed to label the signal antibodies for sensitive electrochemical measurement of alpha-fetoprotein (AFP). The preparation of HRP-Au NRs nanocomposites and the labeling of secondary antibody (Ab2) were performed by one-pot assembly of HRP and Ab2 on the surface of Au NRs. The immunosensor was fabricated by assembling carbon nanotubes (CNTs), Au NRs, and capture antibodies (Ab1) on the glassy carbon electrode. In the presence of AFP antigen, the labels were captured on the surface of the Au NRs/CNTs via specific recognition of antigen-antibody, resulting in the signal intensity being clearly increased. Differential pulse voltammetry (DPV) was employed to record the response signal of the immunosensor in phosphate-buffered saline (PBS) containing hydrogen peroxide (H2O2) and 3,3',5,5'-tetramethylbenzidine (TMB). Under optimal conditions, the signal intensity was linearly related to the concentration of AFP in the range of 0.1-100 ng ml(-1), and the limit of detection was 30 pg ml(-1) (at signal/noise [S/N] = 3). Furthermore, the immunoassay method was evaluated using human serum samples, and the recovery obtained was within 99.0 and 102.7%, indicating that the immunosensor has potential clinical applications.

  6. Increased sexual behavior in male Macaca arctoides monkeys produced by atipamezole, a selective alpha 2-adrenoceptor antagonist.

    PubMed

    Linnankoski, I; Grönroos, M; Carlson, S; Pertovaara, A

    1992-05-01

    The effect of a highly selective and potent alpha 2-adrenoceptor antagonist, atipamezole, on sexual behavior was studied in three stumptail macaques (Macaca arctoides). Following IM administration of atipamezole or saline control, the behavior of the male monkey with a female monkey was observed for 30 min. Atipamezole dose dependently (0.01-0.15 or 0.30 mg/kg) produced a significant increase in the number of ejaculations in all three monkeys, including an old one with decreased sexual activity in control conditions. Both ejaculations obtained by copulation and masturbation were increased. It is concluded that atipamezole is effective in increasing sexual behavior in male stumptail monkeys.

  7. Estrogen Receptors Alpha (ERα) and Beta (ERβ): Subtype-Selective Ligands and Clinical Potential

    PubMed Central

    Paterni, Ilaria; Granchi, Carlotta; Katzenellenbogen, John A.; Minutolo, Filippo

    2014-01-01

    Estrogen receptors alpha (ERα) and beta (ERβ) are nuclear transcription factors that are involved in the regulation of many complex physiological processes in humans. Modulation of these receptors by prospective therapeutic agents is currently being considered for prevention and treatment of a wide variety of pathological conditions, such as, cancer, metabolic and cardiovascular diseases, neurodegeneration, inflammation, and osteoporosis. This review provides an overview and update of compounds that have been recently reported as modulators of ERs, with a particular focus on their potential clinical applications. PMID:24971815

  8. Treatment with anti-LFA-1 alpha monoclonal antibody selectively interferes with the maturation of CD4- 8+ thymocytes.

    PubMed

    Revilla, C; González, A L; Conde, C; López-Hoyos, M; Merino, J

    1997-04-01

    Maturation of T lymphocytes in the thymus is driven by signals provided by soluble factors and by the direct interaction between thymocytes and stromal cells. Although the interaction between T-cell receptor (TCR) and major histocompalibility complex (MHC) molecules on stromal cells is crucial for T-cell development, other accessory molecules seem to play a role in this process. In order to better understand the role of lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) molecules in thymocyte maturation, mice were treated from birth with saturating doses of non-cytolytic-specific monoclonal antibodies. The effect of this treatment on thymocyte subpopulations and the expression of CD3 and TCR-alpha beta by these cells was investigated by flow cytometry. Our data demonstrated that the effective saturation of LFA-1 alpha chain in the thymus, but not ICAM-I or LFA-I beta chain, selectively interfered with the maturation of CD8+ T cells, as manifested by a marked reduction in the frequency of CD4-8+ thymocytes expressing high levels of CD3 and TCR-alpha beta. This selective reduction was also observed in peripheral blood mononuclear cells and spleen cells. The analysis of the frequencies of various V beta TCR showed that CD4-8+ thymocytes were globally affected by the treatment. These results underline the importance of the interaction between LFA-1 and its ligands in the maturation of CD8+ T cells and document the existence of different molecular requirements for the differentiation of CD4+ and CD8+ T cells.

  9. Mesolimbic alpha-, but not beta-adrenoceptors control the accumbal release of dopamine that is derived from reserpine-sensitive storage vesicles.

    PubMed

    Verheij, M M M; Cools, A R

    2009-09-15

    Mesolimbic beta-, but not alpha-adrenoceptors control the accumbal release of dopamine that is derived from alpha-methyl-para-tyrosine-sensitive pools of newly synthesized neurotransmitter. The aim of this study was to investigate which of these adrenoceptors control the accumbal release of dopamine that is derived from reserpine-sensitive pools of previously stored neurotransmitter. Rats, that were divided in low-responders and high-responders to novelty, were pretreated with 1 mg/kg of reserpine before the alpha-adrenergic-agent phentolamine or the beta-adrenergic-agent isoproterenol was locally applied into the nucleus accumbens. The original finding that phentolamine and isoproterenol increased accumbal dopamine levels in low-responders and high-responders was replicated. Reserpine reduced the phentolamine-induced increase of accumbal dopamine in both types of rat. However, phentolamine could still increase accumbal dopamine levels in reserpine-treated high-responders, but not anymore in reserpine-treated low-responders. Reserpine did not reduce the isoproterenol-induced increase of accumbal dopamine in any type of rat. This study demonstrates that mesolimbic alpha-, but not beta-adrenoceptors control the accumbal release of dopamine that is derived from reserpine-sensitive storage vesicles. In addition, these data confirm our previous finding that dopamine can still be released from storage vesicles of reserpinized high-responders, but not of reserpinized low-responders. The collected data underline our notion that alpha- and beta-adrenergic drugs may have therapeutic effects in patients suffering from diseases in which accumbal dopamine is involved.

  10. Control of Pratylenchus brachyurus with Selected Nonfumigant Nematicides on a Tolerant and a Sensitive Soybean Cultivar.

    PubMed

    Koenning, S R; Schmitt, D P

    1987-10-01

    A field study was conducted to evaluate soybean cultivar sensitivity to Pratylenchus brachyurus and selected nonfumigant nematicides for control of this nematode. 'Essex', a tolerant cultivar, yielded more than 'Forrest' , a sensitive cultivar, in an infested field. Plots treated with aldicarb, carbofuran, and fenamiphos had fewer nematodes 40 days after planting than nontreated plots. Plots planted with Forrest and treated with carbofuran had a greater yield than the untreated controls.

  11. Preclinical study on combined chemo- and nonviral gene therapy for sensitization of melanoma using a human TNF-alpha expressing MIDGE DNA vector.

    PubMed

    Kobelt, Dennis; Aumann, Jutta; Schmidt, Manuel; Wittig, Burghardt; Fichtner, Iduna; Behrens, Diana; Lemm, Margit; Freundt, Greta; Schlag, Peter M; Walther, Wolfgang

    2014-05-01

    Nonviral gene therapy represents a realistic option for clinical application in cancer treatment. This preclinical study demonstrates the advantage of using the small-size MIDGE(®) DNA vector for improved transgene expression and therapeutic application. This is caused by significant increase in transcription efficiency, but not by increased intracellular vector copy numbers or gene transfer efficiency. We used the MIDGE-hTNF-alpha vector for high-level expression of hTNF-alpha in vitro and in vivo for a combined gene therapy and vindesine treatment in human melanoma models. The MIDGE vector mediated high-level hTNF-alpha expression leads to sensitization of melanoma cells towards vindesine. The increased efficacy of this combination is mediated by remarkable acceleration and increase of initiator caspase 8 and 9 and effector caspase 3 and 7 activation. In the therapeutic approach, the nonviral intratumoral in vivo jet-injection gene transfer of MIDGE-hTNF-alpha in combination with vindesine causes melanoma growth inhibition in association with increased apoptosis in A375 cell line or patient derived human melanoma xenotransplant (PDX) models. This study represents a proof-of-concept for an anticipated phase I clinical gene therapy trial, in which the MIDGE-hTNF-alpha vector will be used for efficient combined chemo- and nonviral gene therapy of malignant melanoma.

  12. Identification of the alternative spliced form of the alpha 2/delta subunit of voltage sensitive Ca2+ channels expressed in PC12 cells.

    PubMed

    Gilad, B; Shenkar, N; Halevi, S; Trus, M; Atlas, D

    1995-07-07

    The alpha 2/delta subunit of voltage sensitive Ca2+ channels expressed in PC12 has been cloned and partially sequenced. The message observed in Northern blot analysis displays a 7.5 kb transcript, identical in size to mRNA of rabbit skeletal muscle and rat brain. The nucleotide sequence of the cloned alpha 2 subunit of the PC12 specific cDNA is > 99% identical to rat brain sequence and 85% to skeletal muscle. Reverse-transcriptase-polymerase chain reaction (RT-PCR) of the alternative splicing region identifies two deleted regions of 57 bp and 21 bp in PC12 expressed alpha 2/delta transcript. The alternative variant alpha 2e of alpha 2/delta subunit which is expressed in PC12 cells was previously identified in human embryonic kidney (HEK293) cells. RT-PCR analysis show two different sized alternative PCR fragments in rat lung and none in rat spleen, kidney and intestine. Antibodies prepared against a 19 amino acid peptide within the alternative spliced region effectively inhibits [3H]dopamine release in PC12 cells. This implies that the alternatively spliced region is positioned extracellularly and is involved in regulation of the L-type Ca2+ channel-mediated transmitter release.

  13. Tumor necrosis factor-alpha-mediated decrease in glutathione increases the sensitivity of pulmonary vascular endothelial cells to H2O2.

    PubMed Central

    Ishii, Y; Partridge, C A; Del Vecchio, P J; Malik, A B

    1992-01-01

    We examined the effects of tumor necrosis factor-alpha (TNF alpha) stimulation of endothelial cells on the increase in endothelial permeability induced by H2O2. Bovine pulmonary microvascular endothelial cells (BPMVEC) were grown to confluence on a microporous filter and the 125I-albumin clearance rate across the monolayer was determined. Pretreatment with TNF alpha (100 U/ml) for 6 h had no direct effect on transendothelial 125I-albumin permeability. However, TNF alpha pretreatment enhanced the susceptibility of BPMVEC to H2O2; that is, H2O2 (10 microM) alone had no direct effect, whereas H2O2 increased 125I-albumin permeability more than threefold when added to monolayers pretreated for 6 h with TNF alpha. Determination of lactate dehydrogenase release indicated that increased permeability was not due to cytolysis. We measured the intracellular contents of GSH and catalase to determine their possible role in mediating the increased susceptibility to H2O2. TNF alpha treatment (100 U/ml for 6 h) decreased total GSH content and concomitantly increased the oxidized GSH content, but did not alter the cellular catalase activity. The role of GSH was examined by pretreating endothelial cells with 2 mM GSH for 3 h, which produced an 80% increase in intracellular GSH content. GSH repletion inhibited the increased sensitivity of the TNF alpha-treated endothelial cells to H2O2. We tested the effects of xanthine oxidase (XO) inhibition since XO activation may be a source of oxidants responsible for the decrease in cellular GSH content. Pretreatment with 0.5 mM oxypurinol attenuated the synergistic effect of TNF alpha and H2O2 on endothelial permeability. The results indicate that decreased oxidant buffering capacity secondary to TNF alpha-induced reduction in intracellular GSH content mediates the increased susceptibility of endothelial cells to H2O2. This mechanism may contribute to oxidant-dependent vascular endothelial injury in septicemia associated with TNF alpha release

  14. Development of Solution Algorithm and Sensitivity Analysis for Random Fuzzy Portfolio Selection Model

    NASA Astrophysics Data System (ADS)

    Hasuike, Takashi; Katagiri, Hideki

    2010-10-01

    This paper focuses on the proposition of a portfolio selection problem considering an investor's subjectivity and the sensitivity analysis for the change of subjectivity. Since this proposed problem is formulated as a random fuzzy programming problem due to both randomness and subjectivity presented by fuzzy numbers, it is not well-defined. Therefore, introducing Sharpe ratio which is one of important performance measures of portfolio models, the main problem is transformed into the standard fuzzy programming problem. Furthermore, using the sensitivity analysis for fuzziness, the analytical optimal portfolio with the sensitivity factor is obtained.

  15. Selective synthesis and characterization of chlorins as sensitizers for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Montforts, Franz-Peter; Kusch, Dirk; Hoper, Frank; Braun, Stefan; Gerlach, Benjamin; Brauer, Hans-Dieter; Schermann, Guido; Moser, Joerg G.

    1996-04-01

    Chlorin type sensitizers have ideal photophysical properties for an application in PDT. The basic chlorin framework of these sensitizers has to be modified by attachment of lipophilic and hydrophilic residues to achieve a good cell uptake and tumor enrichment. In the present study we describe the selective synthesis of amphiphilic chlorins starting from the readily accessible red blood pigment heme. The photophysical properties of the well defined synthetic chlorins are characterized by photophysical investigations. The kinetic of cell uptake, the localization in the cell and the photodynamic behavior of the amphiphilic sensitizers are demonstrated by incubation of A 375 cancer cell lines with structurally different chlorins.

  16. Selective disruption of ER{alpha} DNA-binding activity alters uterine responsiveness to estradiol.

    PubMed

    Hewitt, Sylvia C; O'Brien, Jeanne E; Jameson, J Larry; Kissling, Grace E; Korach, Kenneth S

    2009-12-01

    In vitro models have been used to demonstrate that estrogen receptors (ERs) can regulate estrogen-responsive genes either by directly interacting with estrogen-responsive element (ERE) DNA motifs or by interacting with other transcription factors such as AP1. In this study, we evaluated estrogen (E(2))-dependent uterine gene profiles by microarray in the KIKO mouse, an in vivo knock-in mouse model that lacks the DNA-binding function of ERalpha and is consequently restricted to non-ERE-mediated responses. The 2- or 24-h E(2)-mediated uterine gene responses were distinct in wild-type (WT), KIKO, and alphaERKO genotypes, indicating that unique sets of genes are regulated by ERE and non-ERE pathways. After 2 h E(2) treatment, 38% of the WT transcripts were also regulated in the KIKO, demonstrating that the tethered mechanism does operate in this in vivo model. Surprisingly, 1438 E(2)-regulated transcripts were unique in the KIKO mouse and were not seen in either WT or alphaERKO. Pathway analyses revealed that some canonical pathways, such as the Jak/Stat pathway, were affected in a similar manner by E(2) in WT and KIKO. In other cases, however, the WT and KIKO differed. One example is the Wnt/beta-catenin pathway; this pathway was impacted, but different members of the pathway were regulated by E(2) or were regulated in a different manner, consistent with differences in biological responses. In summary, this study provides a comprehensive analysis of uterine genes regulated by E(2) via ERE and non-ERE pathways.

  17. (Arylpiperazinyl)cyclohexylsufonamides: discovery of alpha(1a/1d)-selective adrenergic receptor antagonists for the treatment of Benign Prostatic Hyperplasia/Lower Urinary Tract Symptoms (BPH/LUTS).

    PubMed

    Chiu, George; Li, Shengjian; Connolly, Peter J; Pulito, Virginia; Liu, Jingchun; Middleton, Steven A

    2007-06-15

    Benign Prostatic Hyperplasia/Lower Urinary Tract Symptoms (BPH/LUTS) can be effectively treated by alpha(1)-adrenergic receptor antagonists. Unfortunately, all currently marketed alpha(1) blockers produced CV related side effects that are caused by the subtype non-selective nature of the drugs. To overcome this problem, it was postulated that a alpha(1a/1d) subtype selective antagonist would bring more benefit for the treatment of BPH/LUTS. In developing selective alpha(1a/1d) ligands, (arylpiperazinyl)cyclohexylsulfonamides were synthesized and their binding profiles against three cloned human alpha(1)-adrenergic receptor subtypes were evaluated. Many compounds show equal affinity for both alpha(1a) and alpha(1d) subtypes with good selectivity against the alpha(1b) subtype. They also overcome the problem of dopamine receptor affinity that previous analogues had exhibited.

  18. Selecting a sensitive battery of bioassays to detect toxic effects of metals in effluents.

    PubMed

    de Paiva Magalhães, Danielly; da Costa Marques, Mônica Regina; Fernandes Baptista, Darcilio; Forsin Buss, Daniel

    2014-09-07

    The use of bioassay batteries is necessary to evaluate toxic effects at various biological levels. The selection of bioassays without prior testing and determination of the most sensitive/suitable groups for each impact may allow the discharge of effluents that pose a threat to the environment. The present study tested and selected a battery of sensitive ecotoxicological bioassays for detecting toxic effects of metals. The sensitivities of six organisms were evaluated (algae Pseudokirchneriella subcapitata and Chlorella vulgaris, Cladocera Daphnia similis and Ceriodaphnia dubia, and fish Poecilia reticulata and Danio rerio) after exposure to 10 individual metal species deemed toxic to the aquatic environment (Ag(+), Cd(2+), Cu(+), Cu(2+), Cr(3+), Cr(6+), Pb(2+), Ni(2+), Zn(2+), and Hg(2+)) and to real (steel-mill) and laboratory simulated effluents. In the bioassays, fish were the least sensitive; D. rerio showed no sensitivity to any of the effluents tested. P. subcapitata was a good bioindicator of Cr(3+) toxicity, and D. similis was the most sensitive organism to Hg(2+); but the toxic effect of effluents with higher levels of Hg(2+) was better detected by C. dubia. The most sensitive battery of bioassays to detect low concentrations of dissolved metals in effluents was the 72-h chronic test with C. vulgaris and the 48-h acute test with C. dubia.

  19. Platelet and brain alpha 2-adrenoceptors and cardiovascular sensitivity to agonists in dogs suffering from endotoxic shock.

    PubMed

    Hikasa, Y; Fukui, H; Sato, Y; Ogasawara, S; Matsuda, H

    1998-01-01

    We examined the changes in alpha 2-adrenoceptor binding on platelet and brain membranes of dogs treated with a non-lethal dose of endotoxin (0.1 mg/kg intravenously), and the alpha 2-adrenoceptor mediated cardiovascular effects during endotoxin shock. At 2 h, 24 h, and 7 days after endotoxin administration, the number of binding sites (Bmax) of [3H]yohimbine binding decreased and equilibrium dissociation constants (Kd) increased in platelets, whereas both Bmax and Kd decreased in either cerebral cortex or medulla oblongata. After 30 days of endotoxin administration, there were no significant differences in Bmax or Kd between the treated and untreated animals in both platelets and brain tissues. Significant positive correlations were observed for Bmax values between platelets and brain tissues, although negative correlations for Kd values between platelets and brain were not significant. Significant negative correlations were also observed between plasma catecholamine concentrations and platelet alpha 2-adrenoceptor number, and between plasma noradrenaline and medulla alpha 2-adrenoceptor number. Pretreatment with E coli endotoxin diminished cardiovascular effects such as bradycardia, hypotension, and increase in systemic vascular resistance induced by either i.v. clonidine or xylazine. This suggests that alpha 2-adrenoceptor activity is impaired in the central nervous system as well as in the peripheral vascular system during endotoxin shock. Therefore, platelets may in part represent a good model which reflects the alpha 2-adrenoceptor changes in the central nervous system and peripheral vascular system during and after endotoxin shock.

  20. 1-[(Imidazolidin-2-yl)imino]indazole. Highly alpha 2/I1 selective agonist: synthesis, X-ray structure, and biological activity.

    PubMed

    Saczewski, Franciszek; Kornicka, Anita; Rybczyńska, Apolonia; Hudson, Alan L; Miao, Shu Sean; Gdaniec, Maria; Boblewski, Konrad; Lehmann, Artur

    2008-06-26

    Novel benzazole derivatives bearing a (imidazolidin-2-yl)imino moiety at position 1 or 2 were synthesized by reacting 1-amino- or 2-aminobenzazoles with N, N'-bis( tert-butoxycarbonyl)imidazolidine-2-thione in the presence of HgCl 2. Structures of 1-[(imidazolidin-2-yl)imino]indazole (marsanidine, 13a) and free base of the 4-Cl derivative 12e were confirmed by X-ray single crystal structure analysis. Compound 13a was found to be the selective alpha 2-adrenoceptor ligand with alpha 2-adrenoceptor/imidazoline I 1 receptor selectivity ratio of 3879, while 1-[(imidazolidin-2-yl)imino]-7-methylindazole ( 13k) proved to be a mixed alpha 2-adrenoceptor/imidazoline I 1 receptor agonist with alpha 2/I 1 selectivity ratio of 7.2. Compound 13k when administered intravenously to male Wistar rats induced a dose-dependent decrease in mean arterial blood pressure (ED50 = 0.6 microg/kg) and heart rate, which was attenuated following pretreatment with alpha 2A-adrenoceptor antagonist RX821002. Compound 13a may find a variety of medical uses ascribed to alpha 2-adrenoceptor agonists, and its 7-methyl derivative 13k is a good candidate for development as a centrally acting antihypertensive drug.

  1. Alpha-helical hydrophobic polypeptides form proton-selective channels in lipid bilayers

    NASA Technical Reports Server (NTRS)

    Oliver, A. E.; Deamer, D. W.

    1994-01-01

    Proton translocation is important in membrane-mediated processes such as ATP-dependent proton pumps, ATP synthesis, bacteriorhodopsin, and cytochrome oxidase function. The fundamental mechanism, however, is poorly understood. To test the theoretical possibility that bundles of hydrophobic alpha-helices could provide a low energy pathway for ion translocation through the lipid bilayer, polyamino acids were incorporated into extruded liposomes and planar lipid membranes, and proton translocation was measured. Liposomes with incorporated long-chain poly-L-alanine or poly-L-leucine were found to have proton permeability coefficients 5 to 7 times greater than control liposomes, whereas short-chain polyamino acids had relatively little effect. Potassium permeability was not increased markedly by any of the polyamino acids tested. Analytical thin layer chromatography measurements of lipid content and a fluorescamine assay for amino acids showed that there were approximately 135 polyleucine or 65 polyalanine molecules associated with each liposome. Fourier transform infrared spectroscopy indicated that a major fraction of the long-chain hydrophobic peptides existed in an alpha-helical conformation. Single-channel recording in both 0.1 N HCl and 0.1 M KCl was also used to determine whether proton-conducting channels formed in planar lipid membranes (phosphatidylcholine/phosphatidylethanolamine, 1:1). Poly-L-leucine and poly-L-alanine in HCl caused a 10- to 30-fold increase in frequency of conductive events compared to that seen in KCl or by the other polyamino acids in either solution. This finding correlates well with the liposome observations in which these two polyamino acids caused the largest increase in membrane proton permeability but had little effect on potassium permeability. Poly-L-leucine was considerably more conductive than poly-L-alanine due primarily to larger event amplitudes and, to a lesser extent, a higher event frequency. Poly-L-leucine caused two

  2. General Approach to the Formation of Sensitive, Selective, Rapidly Responding Conductometric Sensors

    NASA Astrophysics Data System (ADS)

    Gole, James; Ozdemir, Serdar

    2009-11-01

    Rapidly responding, reversible, sensitive, and selective porous silicon-based gas sensors are formed with a highly efficient electrical contact to a nanopore covered microporous array. A general approach to facilitate significant changes in sensor surface sensitivity for a variety of gases, based on a complementary concept to that of hard and soft acid and base (HSAB) interactions and commensurate with a basis in physisorption has now been formulated to create highly selective surface coatings at the nanoscale. The technology, implemented on ``phase matched'' nanoporous silicon layers positioned on porous silicon micropores facilitates the application of nanostructured metals, metal oxides, and nanoparticle catalytic coatings, and provides for notably higher sensitivities and selectivity verses, for example, metal oxide systems. Nanomaterials are applied to the PS surface to provide for the detection of gases including NO, NO2, CO, NH3, PH3, SO2, H2S, and HCl in an array-based format at the sub-ppm level. The value of this sensor technology results from (1) sensitivity and short recovery time, (2) operation at room temperature with an insensitivity to temperature drift, (3) ease of coating with diversity of clearly mapped gas-selective materials to form sensor arrays, (5) its low cost of fabrication.

  3. Potentiation of alpha7-containing nicotinic acetylcholine receptors by select albumins.

    PubMed

    Conroy, William G; Liu, Qing-Song; Nai, Qiang; Margiotta, Joseph F; Berg, Darwin K

    2003-02-01

    Nicotinic receptors containing alpha7 subunits are ligand-gated ion channels widely distributed in the nervous system; they influence a diverse array of events because of their high relative calcium permeability. We show here that nicotine-induced whole-cell responses generated by such receptors can be dramatically potentiated in a rapidly reversible manner by some but not all albumins. The potentiation involves increases both in potency and efficacy with no obvious differences in rise and fall times of the response. The potentiation is not reduced by removing absorbed components; it is abolished by proteolysis, suggesting that the albumin protein backbone is essential. The fact that some albumins are ineffective indicates that minor differences in amino acid sequence may be critical. Experiments with open channel blockers indicate that the potentiation involves increased responses from active receptors rather than recruitment of receptors from a previously silent pool. Single channel recordings reveal that the potentiation correlates with increased single channel opening probability, reflected in increased frequency of channel opening and increased mean channel open time. The potentiation can be exploited to overcome blockade by noncompetitive inhibitors such as beta-amyloid peptide. The results raise the possibility that endogenous compounds use the site to modulate receptor function in vivo, and suggest that the receptors may represent useful targets for therapeutic intervention in cases where they have been implicated in neuropathologies such as Alzheimer's disease.

  4. Highly Sensitive and Selective Ethanol Sensor Fabricated with In-Doped 3DOM ZnO.

    PubMed

    Wang, Zhihua; Tian, Ziwei; Han, Dongmei; Gu, Fubo

    2016-03-02

    ZnO is an important n-type semiconductor sensing material. Currently, much attention has been attracted to finding an effective method to prepare ZnO nanomaterials with high sensing sensitivity and excellent selectivity. A three-dimensionally ordered macroporous (3DOM) ZnO nanostructure with a large surface area is beneficial to gas and electron transfer, which can enhance the gas sensitivity of ZnO. Indium (In) doping is an effective way to improve the sensing properties of ZnO. In this paper, In-doped 3DOM ZnO with enhanced sensitivity and selectivity has been synthesized by using a colloidal crystal templating method. The 3DOM ZnO with 5 at. % of In-doping exhibits the highest sensitivity (∼88) to 100 ppm ethanol at 250 °C, which is approximately 3 times higher than that of pure 3DOM ZnO. The huge improvement to the sensitivity to ethanol was attributed to the increase in the surface area and the electron carrier concentration. The doping by In introduces more electrons into the matrix, which is helpful for increasing the amount of adsorbed oxygen, leading to high sensitivity. The In-doped 3DOM ZnO is a promising material for a new type of ethanol sensor.

  5. Sulindac sulfide selectively increases sensitivity of ABCC1 expressing tumor cells to doxorubicin and glutathione depletion.

    PubMed

    Whitt, Jason D; Keeton, Adam B; Gary, Bernard D; Sklar, Larry A; Sodani, Kamlesh; Chen, Zhe-Sheng; Piazza, Gary A

    2016-03-01

    ATP-binding cassette (ABC) transporters ABCC1 (MRP1), ABCB1 (P-gp), and ABCG2 (BCRP) contribute to chemotherapy failure. The primary goals of this study were to characterize the efficacy and mechanism of the nonsteroidal anti-inflammatory drug (NSAID), sulindac sulfide, to reverse ABCC1 mediated resistance to chemotherapeutic drugs and to determine if sulindac sulfide can influence sensitivity to chemotherapeutic drugs independently of drug efflux. Cytotoxicity assays were performed to measure resistance of ABC-expressing cell lines to doxorubicin and other chemotherapeutic drugs. NSAIDs were tested for the ability to restore sensitivity to resistance selected tumor cell lines, as well as a large panel of standard tumor cell lines. Other experiments characterized the mechanism by which sulindac sulfide inhibits ABCC1 substrate and co-substrate (GSH) transport in isolated membrane vesicles and intact cells. Selective reversal of multi-drug resistance (MDR), decreased efflux of doxorubicin, and fluorescent substrates were demonstrated by sulindac sulfide and a related NSAID, indomethacin, in resistance selected and engineered cell lines expressing ABCC1, but not ABCB1 or ABCG2. Sulindac sulfide also inhibited transport of leukotriene C4 into membrane vesicles. Sulindac sulfide enhanced the sensitivity to doxorubicin in 24 of 47 tumor cell lines, including all melanoma lines tested (7-7). Sulindac sulfide also decreased intracellular GSH in ABCC1 expressing cells, while the glutathione synthesis inhibitor, BSO, selectively increased sensitivity to sulindac sulfide induced cytotoxicity. Sulindac sulfide potently and selectively reverses ABCC1-mediated MDR at clinically achievable concentrations. ABCC1 expressing tumors may be highly sensitive to the direct cytotoxicity of sulindac sulfide, and in combination with chemotherapeutic drugs that induce oxidative stress.

  6. Sulindac sulfide selectively increases sensitivity of ABCC1 expressing tumor cells to doxorubicin and glutathione depletion

    PubMed Central

    Whitt, Jason D.; Keeton, Adam B.; Gary, Bernard D.; Sklar, Larry A.; Sodani, Kamlesh; Chen, Zhe-Sheng; Piazza, Gary A.

    2016-01-01

    Abstract ATP-binding cassette (ABC) transpo rters ABCC1 (MRP1), ABCB1 (P-gp), and ABCG2 (BCRP) contribute to chemotherapy failure. The primary goals of this study were to characterize the efficacy and mechanism of the non­steroidal anti-inflammatory drug (NSAID), sulindac sulfide, to reverse ABCC1 mediated resistance to chemother­apeutic drugs and to determine if sulindac sulfide can influence sensitivity to chemotherapeutic drugs independently of drug efflux. Cytotoxicity assays were performed to measure resistance of ABC-expressing cell lines to doxoru­bicin and other chemotherapeutic drugs. NSAIDs were tested for the ability to restore sensitivity to resistance selected tumor cell lines, as well as a large panel of standard tumor cell lines. Other experiments characterized the mechanism by which sulindac sulfide inhibits ABCC1 substrate and co-substrate (GSH) transport in isolated membrane vesicles and intact cells. Selective reversal of multi-drug resistance (MDR), decreased efflux of doxor­ubicin, and fluorescent substrates were demonstrated by sulindac sulfide and a related NSAID, indomethacin, in resistance selected and engineered cell lines expressing ABCC1, but not ABCB1 or ABCG2. Sulindac sulfide also inhibited transport of leukotriene C4 into membrane vesicles. Sulindac sulfide enhanced the sensitivity to doxoru­bicin in 24 of 47 tumor cell lines, including all melanoma lines tested (7-7). Sulindac sulfide also decreased intra­cellular GSH in ABCC1 expressing cells, while the glutathione synthesis inhibitor, BSO, selectively increased sensitivity to sulindac sulfide induced cytotoxicity. Sulindac sulfide potently and selectively reverses ABCC1-mediated MDR at clinically achievable concentrations. ABCC1 expressing tumors may be highly sensitive to the direct cytotoxicity of sulindac sulfide, and in combination with chemotherapeutic drugs that induce oxidative stress. PMID:28276667

  7. A Novel Positive Selection for Identifying Cold-Sensitive Myosin II Mutants in Dictyostelium

    PubMed Central

    Patterson, B.; Spudich, J. A.

    1995-01-01

    We developed a positive selection for myosin heavy chain mutants in Dictyostelium. This selection is based on the fact that brief exposure to azide causes wild-type cells to release from the substrate, whereas myosin null cells remain adherent. This procedure assays myosin function on a time scale of minutes and has therefore allowed us to select rapid-onset cold-sensitive mutants after random chemical mutagenesis of Dictyostelium cells. We developed a rapid technique for determining which mutations lie in sequences of the myosin gene that encode the head (motor) domain and localized 27 of 34 mutants to this domain. We recovered the appropriate sequences from five of the mutants and demonstrated that they retain their cold-sensitive properties when expressed from extrachromosomal plasmids. PMID:7498732

  8. Anti-Parkinson effects of a selective alpha2C-adrenoceptor antagonist in the MPTP marmoset model.

    PubMed

    Philippens, Ingrid H C H M; Joosen, Marloes J A; Ahnaou, Abdellah; Andres, Ignacio; Drinkenburg, Wilhelmus Pim H I M

    2014-08-01

    Current dopamine replacement therapies, in Parkinson's disease (PD), result in aversive side effects and rapid drug dose escalation over time. Therefore, a non-dopaminergic treatment would be an advantageous supplement to lower the dose of dopamine replacement treatment postponing the occurrence of side effects. The noradrenergic system plays an important role in the facilitation or maintenance of the activity of the nigrostriatal dopamine pathways. Here the putative anti-Parkinson effects of the oral selective alpha2C-adrenoceptor antagonist (JNJ27063699 0.1-10mg/kg p.o.) and of vehicle (fruit syrup) were evaluated in the MPTP-marmoset model. Dose-related anti-Parkinson effects were assessed by means of a behavioural rating scale covering parkinsonian symptoms, body weight and body temperature, and two test systems assessing locomotor activity and complex motor skills of hand-eye coordination for controlled movements in MPTP- or saline-pretreated marmosets. JNJ27063699, at the middle and higher doses, consistently improved locomotor activity and hand-eye coordination capabilities, which indicates an improvement in the coordination of motor control -or movements- in MPTP-pretreated monkeys. No additional effects on the parkinsonian symptoms or side effects were observed on other test systems. Overall, the findings link deficit in motor coordination with dysfunctional adrenergic signalling and it suggest that selective alpha2C adrenergic antagonism may contribute to behavioural improvement in the MPTP-monkey model of PD. In multi-drug medication JNJ27063699 might have potential in the treatment of motor deficit in PD.

  9. Reaction rate sensitivity of 44Ti production in massive stars and implications of a thick target yield measurement of 40Ca(alpha,gamma)44Ti

    SciTech Connect

    Hoffman, R D; Sheets, S A; Burke, J T; Scielzo, N D; Rauscher, T; Norman, E B; Tumey, S; Brown, T A; Grant, P G; Hurst, A M; Phair, L; Stoyer, M A; Wooddy, T; Fisker, J L; Bleuel, D

    2010-02-16

    We evaluate two dominant nuclear reaction rates and their uncertainties that affect {sup 44}Ti production in explosive nucleosynthesis. Experimentally we develop thick-target yields for the {sup 40}Ca({alpha},{gamma}){sup 44}Ti reaction at E{sub {alpha}} = 4.13, 4.54, and 5.36 MeV using {gamma}-ray spectroscopy. At the highest beam energy, we also performed an activation measurement which agrees with the thick target result. From the measured yields a stellar reaction rate was developed that is smaller than current statistical-model calculations and recent experimental results, which would suggest lower {sup 44}Ti production in scenarios for the {alpha}-rich freeze out. Special attention has been paid to assessing realistic uncertainties of stellar reaction rates produced from a combination of experimental and theoretical cross sections. With such methods, we also develop a re-evaluation of the {sup 44}Ti({alpha},p){sup 47}V reaction rate. Using these two rates we carry out a sensitivity survey of {sup 44}Ti synthesis in eight expansions representing peak temperature and density conditions drawn from a suite of recent supernova explosion models. Our results suggest that the current uncertainty in these two reaction rates could lead to as large an uncertainty in {sup 44}Ti synthesis as that produced by different treatments of stellar physics.

  10. Study of the cortical representation of whisker frequency selectivity using voltage-sensitive dye optical imaging

    PubMed Central

    Tsytsarev, Vassiliy; Pumbo, Elena; Tang, Qinggong; Chen, Chao-Wei; Kalchenko, Vyacheslav; Chen, Yu

    2016-01-01

    ABSTRACT The facial whiskers of rodents act as a high-resolution tactile apparatus that allow the animal to detect the finest details of its environment. Previously it was shown that whisker-sensitive neurons in the somatosensory cortex show frequency selectivity to small amplitude stimuli, An intravital voltage-sensitive dye optical imaging (VSDi) method in combination with the different frequency whisker stimulation was used in order to visualize neural activity in the mice somatosensory cortex in response to the stimulation of a single whisker by different frequencies. Using the intravital voltage-sensitive dye optical imaging (VSDi) method in combination with the different frequency whisker stimulation we visualized neural activity in the mice somatosensory cortex in response to the stimulation of a single whisker by different frequencies. We found that whisker stimuli with different frequencies led to different optical signals in the barrel field. Our results provide evidence that different neurons of the barrel cortex have different frequency preferences. This supports prior research that whisker deflections cause responses in cortical neurons within the barrel field according to the frequency of the stimulation. Many studies of the whisker frequency selectivity were performed using unit recording but to map spatial organization, imaging methods are essential. In the work described in the present paper, we take a serious step toward detailed functional mapping of the somatosensory cortex using VSDi. To our knowledge, this is the first demonstration of whisker frequency sensitivity and selectivity of barrel cortex neurons with optical imaging methods. PMID:28243518

  11. Darwinian fitness and the intensity of natural selection: studies in sensitivity analysis.

    PubMed

    Demetrius, Lloyd; Matthias Gundlach, Volker; Ziehe, Martin

    2007-12-21

    Darwinian fitness, the capacity of a variant type to establish itself in competition with the resident population, is determined by evolutionary entropy, a measure of the uncertainty in age of the mother of a randomly chosen newborn. This article shows that the intensity of natural selection, as measured by the sensitivity of entropy with respect to changes in the age-specific fecundity and mortality variables, is a convex function of age, decreasing at early and increasing at later ages. We exploit this result to provide quantitative evolutionary explanations of the large variation in survivorship curves observed in natural populations. Previous studies to explain variation in survivorship curves have been based on the proposition that Darwinian fitness is determined by the Malthusian parameter. Hence the intensity of natural selection will be determined by the sensitivity of the Malthusian parameter with respect to changes in the age-specific fecundity and mortality variables. This measure of the selection gradient is known to be a decreasing function of age, with implications which are inconsistent with empirical observations of survivorship curves in human and animal populations. The analysis described in this paper point to the mitigated import of sensitivity studies based on the Malthusian parameter. Our analysis provides theoretical and empirical support for the ecological and evolutionary significance of sensitivity analysis based on entropy, which is the appropriate measure of Darwinian fitness.

  12. The Ca2+ sensitizer CK‐2066260 increases myofibrillar Ca2+ sensitivity and submaximal force selectively in fast skeletal muscle

    PubMed Central

    Cheng, Arthur J.; Hartman, James J.; Hinken, Aaron C.; Lee, Ken; Durham, Nickie; Russell, Alan J.; Malik, Fady I.; Westerblad, Håkan; Jasper, Jeffrey R.

    2017-01-01

    Key points We report that the small molecule CK‐2066260 selectively slows the off‐rate of Ca2 + from fast skeletal muscle troponin, leading to increased myofibrillar Ca2 + sensitivity in fast skeletal muscle.Rodents dosed with CK‐2066260 show increased hindlimb muscle force and power in response to submaximal rates of nerve stimulation in situ.CK‐2066260 has no effect on free cytosolic [Ca2 +] during contractions of isolated muscle fibres.We conclude that fast skeletal muscle troponin sensitizers constitute a potential therapy to address an unmet need of improving muscle function in conditions of weakness and premature muscle fatigue. Abstract Skeletal muscle dysfunction occurs in many diseases and can lead to muscle weakness and premature muscle fatigue. Here we show that the fast skeletal troponin activator, CK‐2066260, counteracts muscle weakness by increasing troponin Ca2+ affinity, thereby increasing myofibrillar Ca2+ sensitivity. Exposure to CK‐2066260 resulted in a concentration‐dependent increase in the Ca2+ sensitivity of ATPase activity in isolated myofibrils and reconstituted hybrid sarcomeres containing fast skeletal muscle troponin C. Stopped‐flow experiments revealed a ∼2.7‐fold decrease in the Ca2+ off‐rate of isolated troponin complexes in the presence of CK‐2066260 (6 vs. 17 s−1 under control conditions). Isolated mouse flexor digitorum brevis fibres showed a rapidly developing, reversible and concentration‐dependent force increase at submaximal stimulation frequencies. This force increase was not accompanied by any changes in the free cytosolic [Ca2+] or its kinetics. CK‐2066260 induced a slowing of relaxation, which was markedly larger at 26°C than at 31°C and could be linked to the decreased Ca2+ off‐rate of troponin C. Rats dosed with CK‐2066260 showed increased hindlimb isometric and isokinetic force in response to submaximal rates of nerve stimulation in situ producing significantly higher absolute forces

  13. Pertussis toxin-sensitive G-protein mediates the alpha 2-adrenergic receptor inhibition of melatonin release in photoreceptive chick pineal cell cultures

    SciTech Connect

    Pratt, B.L.; Takahashi, J.S.

    1988-07-01

    The avian pineal gland is a photoreceptive organ that has been shown to contain postjunctional alpha 2-adrenoceptors that inhibit melatonin synthesis and/or release upon receptor activation. Physiological response and (32P)ADP ribosylation experiments were performed to investigate whether pertussis toxin-sensitive guanine nucleotide-binding proteins (G-proteins) were involved in the transduction of the alpha 2-adrenergic signal. For physiological response studies, the effects of pertussis toxin on melatonin release in dissociated cell cultures exposed to norepinephrine were assessed. Pertussis toxin blocked alpha 2-adrenergic receptor-mediated inhibition in a dose-dependent manner. Pertussis toxin-induced blockade appeared to be noncompetitive. One and 10 ng/ml doses of pertussis toxin partially blocked and a 100 ng/ml dose completely blocked norepinephrine-induced inhibition. Pertussis toxin-catalyzed (32P)ADP ribosylation of G-proteins in chick pineal cell membranes was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. Membranes were prepared from cells that had been pretreated with 0, 1, 10, or 100 ng/ml pertussis toxin. In the absence of pertussis toxin pretreatment, two major proteins of 40K and 41K mol wt (Mr) were labeled by (32P)NAD. Pertussis toxin pretreatment of pineal cells abolished (32P) radiolabeling of the 40K Mr G-protein in a dose-dependent manner. The norepinephrine-induced inhibition of both cAMP efflux and melatonin release, as assessed by RIA of medium samples collected before membrane preparation, was also blocked in a dose-dependent manner by pertussis toxin. Collectively, these results suggest that a pertussis toxin-sensitive 40K Mr G-protein labeled by (32P)NAD may be functionally associated with alpha 2-adrenergic signal transduction in chick pineal cells.

  14. An alpha-helical cationic antimicrobial peptide selectively modulates macrophage responses to lipopolysaccharide and directly alters macrophage gene expression.

    PubMed

    Scott, M G; Rosenberger, C M; Gold, M R; Finlay, B B; Hancock, R E

    2000-09-15

    Certain cationic antimicrobial peptides block the binding of LPS to LPS-binding protein and reduce the ability of LPS to induce the production of inflammatory mediators by macrophages. To gain a more complete understanding of how LPS activates macrophages and how cationic peptides influence this process, we have used gene array technology to profile gene expression patterns in macrophages treated with LPS in the presence or the absence of the insect-derived cationic antimicrobial peptide CEMA (cecropin-melittin hybrid). We found that CEMA selectively blocked LPS-induced gene expression in the RAW 264.7 macrophage cell line. The ability of LPS to induce the expression of >40 genes was strongly inhibited by CEMA, while LPS-induced expression of another 16 genes was relatively unaffected. In addition, CEMA itself induced the expression of a distinct set of 35 genes, including genes involved in cell adhesion and apoptosis. Thus, CEMA, a synthetic alpha-helical peptide, selectively modulates the transcriptional response of macrophages to LPS and can alter gene expression in macrophages.

  15. Sequence diversity, natural selection and linkage disequilibrium in the human T cell receptor alpha/delta locus.

    PubMed

    Mackelprang, Rachel; Livingston, Robert J; Eberle, Michael A; Carlson, Christopher S; Yi, Qian; Akey, Joshua M; Nickerson, Deborah A

    2006-04-01

    T cell receptors (TR), through their interaction with the major histocompatibility complex, play a central role in immune responsiveness and potentially immune-related disorders. We resequenced all 57 variable (V) genes in the human T cell receptor alpha and delta (TRA/TRD) locus in 40 individuals of Northern European, Mexican, African-American and Chinese descent. Two hundred and eighty-four single nucleotide polymorphisms (SNPs) were identified. The distribution of SNPs between V genes was heterogeneous, with an average of five SNPs per gene and a range of zero to 15. We describe the patterns of linkage disequilibrium for these newly discovered SNPs and compare these patterns with other emerging large-scale datasets (e.g. Perlegen and HapMap projects) to place our findings into a framework for future analysis of genotype-phenotype associations across this locus. Furthermore, we explore signatures of natural selection across V genes. We find evidence of strong directional selection at this locus as evidenced by unusually high values of Fst.

  16. Antireflection treatment of thickness sensitive spectrally selective (TSSS) paints for thermal solar absorbers

    SciTech Connect

    Lundh, M.; Waeckelgaard, E.; Blom, T.

    2010-01-15

    There are several methods to produce solar absorbers, and one cheap alternative is painted absorbers, preferably painted with a spectrally selective paint. The optical properties of Thickness Sensitive Spectrally Selective (TSSS) paints are, however, limited by the thickness of the paint layer. In this study it is shown that the solar absorptance of two commercial TSSS paints can be increased between 0.01 and 0.02 units with an antireflection treatment using a silicon dioxide layer deposited from silica-gel. It was found that the thermal emittance (100 C) did not change significantly after the treatment. (author)

  17. A Novel Fluorescent Probe for the Highly Selective and Sensitive Detection of Palladium in Aqueous Medium.

    PubMed

    Ma, Zhiwei; Wang, Xiao; Sun, Yanling; Liu, Juntao; Tong, Yan; Liu, Zhijing

    2016-11-01

    Based on the Pd(0)-catalyzed Tsuji-Trost allylic oxidative insertion reaction, we developed a fluorescent probe PdL1 for sensing Pd(0). As expected, probe PdL1 exhibited high selectivity and excellent sensitivity in both absorbance and fluorescence detection of Pd(0) in CH3CH2OH/PBS (10 mM, pH = 7.4, 6:4, v/v) solution. The detection limit was calculated to be as low as 15 nM, which can meet the selective requirements for practical application.

  18. Physical properties of H alpha selected star forming galaxies at z = 0.84

    NASA Astrophysics Data System (ADS)

    Villar; V.; Gallego, J.; Pérez-González, P. G.; Barro, G.; Pascual, S.; Zamorano, J.; Noeske, K.; Koo, D.

    2011-11-01

    In this work we analyze the star formation rates and stellar masses of a sample of 157 star forming galaxies at z ˜ 0.84 (Villar et al. 2008), selected by their Hα flux with a narrow band filter. We compare star formation rates (SFR) measured with different tracers (Hα, UV and IR) finding that they are in good agreement after extinction correction, although with some scatter. We find a correlation between the ratios SFR_{FUV}/SFR_{Hα}, SFR_{IR}/SFR_{Hα} and the EW(Hα) (i.e. weighted age) which accounts for part of this scatter. We obtained stellar mass estimations fitting templates to multi-wavelength photometry. The typical stellar mass of a galaxy within our sample is ˜ 2 x 10^{10} M_⊙. The specific star formation rate (sSFR) decreases with it, indicating that massive galaxies are less affected by star formation processes than less massive ones. In addition, the sSFR is, for a fixed mass, higher in the Universe at z˜ 0.84 than in the local one. Both results are consistent with the downsizing scenario. To quantify this downsizing we estimated the quenching masses for our sample at z ˜ 0.84 and a local sample also selected by Hα, finding that it declines from M_Q ˜ 10^{12} M_⊙ at z ˜ 0.84 to M_Q ˜ 8 x 10^{10} M_⊙ at the local Universe.

  19. Reactive chromophores for sensitive and selective detection of chemical warfare agents and toxic industrial chemicals

    NASA Astrophysics Data System (ADS)

    Frye-Mason, Greg; Leuschen, Martin; Wald, Lara; Paul, Kateri; Hancock, Lawrence F.

    2005-05-01

    A reactive chromophore developed at MIT exhibits sensitive and selective detection of surrogates for G-class nerve agents. This reporter acts by reacting with the agent to form an intermediate that goes through an internal cyclization reaction. The reaction locks the molecule into a form that provides a strong fluorescent signal. Using a fluorescent sensor platform, Nomadics has demonstrated rapid and sensitive detection of reactive simulants such as diethyl chloro-phosphate (simulant for sarin, soman, and related agents) and diethyl cyanophosphate (simulant for tabun). Since the unreacted chromophore does not fluoresce at the excitation wavelength used for the cyclized reporter, the onset of fluo-rescence can be easily detected. This fluorescence-based detection method provides very high sensitivity and could enable rapid detection at permissible exposure levels. Tests with potential interferents show that the reporter is very selective, with responses from only a few highly toxic, electrophilic chemicals such as phosgene, thionyl chloride, and strong acids such as HF, HCl, and nitric acid. Dimethyl methyl phosphonate (DMMP), a common and inactive simu-lant for other CW detectors, is not reactive enough to generate a signal. The unique selectivity to chemical reactivity means that a highly toxic and hazardous chemical is present when the reporter responds and illustrates that this sensor can provide very low false alarm rates. Current efforts focus on demonstrating the sensitivity and range of agents and toxic industrial chemicals detected with this reporter as well as developing additional fluorescent reporters for a range of chemical reactivity classes. The goal is to produce a hand-held sensor that can sensitively detect a broad range of chemical warfare agent and toxic industrial chemical threats.

  20. Bayesian sensitivity analysis of incomplete data: bridging pattern-mixture and selection models.

    PubMed

    Kaciroti, Niko A; Raghunathan, Trivellore

    2014-11-30

    Pattern-mixture models (PMM) and selection models (SM) are alternative approaches for statistical analysis when faced with incomplete data and a nonignorable missing-data mechanism. Both models make empirically unverifiable assumptions and need additional constraints to identify the parameters. Here, we first introduce intuitive parameterizations to identify PMM for different types of outcome with distribution in the exponential family; then we translate these to their equivalent SM approach. This provides a unified framework for performing sensitivity analysis under either setting. These new parameterizations are transparent, easy-to-use, and provide dual interpretation from both the PMM and SM perspectives. A Bayesian approach is used to perform sensitivity analysis, deriving inferences using informative prior distributions on the sensitivity parameters. These models can be fitted using software that implements Gibbs sampling.

  1. Perceived egocentric distance sensitivity and invariance across scene-selective cortex

    PubMed Central

    Persichetti, Andrew S.; Dilks, Daniel D.

    2016-01-01

    Behavioral studies in many species and studies in robotics have demonstrated two sources of information critical for visually-guided navigation: sense (left-right) information and egocentric distance (proximal-distal) information. A recent fMRI study found sensitivity to sense information in two scene-selective cortical regions, the retrosplenial complex (RSC) and the occipital place area (OPA), consistent with hypotheses that these regions play a role in human navigation. Surprisingly, however, another scene-selective region, the parahippocampal place area (PPA), was not sensitive to sense information, challenging hypotheses that this region is directly involved in navigation. Here we examined how these regions encode egocentric distance information (e.g., a house seen from close up versus far away), another type of information crucial for navigation. Using fMRI adaptation and a regions-of-interest analysis approach in human adults, we found sensitivity to egocentric distance information in RSC and OPA, while PPA was not sensitive to such information. These findings further support that RSC and OPA are directly involved in navigation, while PPA is not, consistent with the hypothesis that scenes may be processed by distinct systems guiding navigation and recognition. PMID:26963085

  2. A 3D Chemically Modified Graphene Hydrogel for Fast, Highly Sensitive, and Selective Gas Sensor

    PubMed Central

    Wu, Jin; Tao, Kai; Guo, Yuanyuan; Li, Zhong; Wang, Xiaotian; Luo, Zhongzhen; Du, Chunlei; Chen, Di; Norford, Leslie K.

    2016-01-01

    Reduced graphene oxide (RGO) has proved to be a promising candidate in high‐performance gas sensing in ambient conditions. However, trace detection of different kinds of gases with simultaneously high sensitivity and selectivity is challenging. Here, a chemiresistor‐type sensor based on 3D sulfonated RGO hydrogel (S‐RGOH) is reported, which can detect a variety of important gases with high sensitivity, boosted selectivity, fast response, and good reversibility. The NaHSO3 functionalized RGOH displays remarkable 118.6 and 58.9 times higher responses to NO2 and NH3, respectively, compared with its unmodified RGOH counterpart. In addition, the S‐RGOH sensor is highly responsive to volatile organic compounds. More importantly, the characteristic patterns on the linearly fitted response–temperature curves are employed to distinguish various gases for the first time. The temperature of the sensor is elevated rapidly by an imbedded microheater with little power consumption. The 3D S‐RGOH is characterized and the sensing mechanisms are proposed. This work gains new insights into boosting the sensitivity of detecting various gases by combining chemical modification and 3D structural engineering of RGO, and improving the selectivity of gas sensing by employing temperature dependent response characteristics of RGO for different gases. PMID:28331786

  3. Selecting focal species as surrogates for imperiled species using relative sensitivities derived from occupancy analysis

    USGS Publications Warehouse

    Silvano, Amy; Guyer, Craig; Steury, Todd; Grand, James B.

    2017-01-01

    Most imperiled species are rare or elusive and difficult to detect, which makes gathering data to estimate their response to habitat restoration a challenge. We used a repeatable, systematic method for selecting focal species using relative sensitivities derived from occupancy analysis. Our objective was to select suites of focal species that would be useful as surrogates when predicting effects of restoration of habitat characteristics preferred by imperiled species. We developed 27 habitat profiles that represent general habitat relationships for 118 imperiled species. We identified 23 regularly encountered species that were sensitive to important aspects of those profiles. We validated our approach by examining the correlation between estimated probabilities of occupancy for species of concern and focal species selected using our method. Occupancy rates of focal species were more related to occupancy rates of imperiled species when they were sensitive to more of the parameters appearing in profiles of imperiled species. We suggest that this approach can be an effective means of predicting responses by imperiled species to proposed management actions. However, adequate monitoring will be required to determine the effectiveness of using focal species to guide management actions.

  4. Facile and selective synthesis of oligothiophene-based sensitizer isomers: an approach toward efficient dye-sensitized solar cells.

    PubMed

    Feng, Quanyou; Zhang, Qian; Lu, Xuefeng; Wang, Hong; Zhou, Gang; Wang, Zhong-Sheng

    2013-09-25

    Two sets of isomeric organic dyes with n-hexyl (DH and AH) or 2-ethylhexyl (DEH and AEH) groups substituted at the spacer part have been designed and straightforwardly synthesized via a facile and selective synthetic route. The structure difference between the isomers stands at the position of the incorporated alkyl chains which are introduced into the terthiophene spacer close to the donor (D) or anchor (A) side. The relationship between the isomeric structures and the optoelectronic properties are systematically investigated. It is found that, in the D series dyes, the alkyl group is much closer to the aromatic donor moiety, which brings about strong steric hindrance and therefore causes a remarkable twist in the molecular skeleton. In contrast, a more planar chemical structure and more effective π-conjugation are realized in the A series dye isomers. Consequently, the A series isomeric dyes demonstrate bathochromically shifted absorption bands, resulting in the improved light-harvesting capability and enhanced photo-generated current. However, the D series isomeric dyes with more twisted molecular skeleton have suppressed the intermolecular interactions and retarded the charge recombination more efficiently, which induces higher open-circuit photovoltage. Combining the two effects on the performance of the fabricated dye-sensitized solar cells (DSSC), the influence from the short-circuit photocurrent plays a more significant role on the power conversion efficiency (η). As a result, isomer AEH-based DSSC with quasi-solid-state electrolyte displays the highest η of 7.10% which remained at 98% of the initial value after continuous light soaking for 1000 h. Promisingly, a η of 8.66% has been achieved for AEH-based DSSC with liquid electrolyte containing Co(II)/(III) redox couple. This work presents the crucial issue of molecular engineering and paves a way to design organic sensitizers for highly efficient and stable DSSCs.

  5. Prothymosin Alpha Selectively Enhances Estrogen Receptor Transcriptional Activity by Interacting with a Repressor of Estrogen Receptor Activity

    PubMed Central

    Martini, Paolo G. V.; Delage-Mourroux, Regis; Kraichely, Dennis M.; Katzenellenbogen, Benita S.

    2000-01-01

    We find that prothymosin alpha (PTα) selectively enhances transcriptional activation by the estrogen receptor (ER) but not transcriptional activity of other nuclear hormone receptors. This selectivity for ER is explained by PTα interaction not with ER, but with a 37-kDa protein denoted REA, for repressor of estrogen receptor activity, a protein that we have previously shown binds to ER, blocking coactivator binding to ER. We isolated PTα, known to be a chromatin-remodeling protein associated with cell proliferation, using REA as bait in a yeast two-hybrid screen with a cDNA library from MCF-7 human breast cancer cells. PTα increases the magnitude of ERα transcriptional activity three- to fourfold. It shows lesser enhancement of ERβ transcriptional activity and has no influence on the transcriptional activity of other nuclear hormone receptors (progesterone receptor, glucocorticoid receptor, thyroid hormone receptor, or retinoic acid receptor) or on the basal activity of ERs. In contrast, the steroid receptor coactivator SRC-1 increases transcriptional activity of all of these receptors. Cotransfection of PTα or SRC-1 with increasing amounts of REA, as well as competitive glutathione S-transferase pulldown and mammalian two-hybrid studies, show that REA competes with PTα (or SRC-1) for regulation of ER transcriptional activity and suppresses the ER stimulation by PTα or SRC-1, indicating that REA can function as an anticoactivator in cells. Our data support a model in which PTα, which does not interact with ER, selectively enhances the transcriptional activity of the ER but not that of other nuclear receptors by recruiting the repressive REA protein away from ER, thereby allowing effective coactivation of ER with SRC-1 or other coregulators. The ability of PTα to directly interact in vitro and in vivo with REA, a selective coregulator of the ER, thereby enabling the interaction of ER with coactivators, appears to explain its ability to selectively enhance

  6. Synthesis and computational investigation of molecularly imprinted nanospheres for selective recognition of alpha-tocopherol succinate

    PubMed Central

    Piacham, Theeraphon; Nantasenamat, Chanin; Isarankura-Na-Ayudhya, Chartchalerm; Prachayasittikul, Virapong

    2013-01-01

    Molecularly imprinted polymers (MIPs) are macromolecular matrices that can mimic the functional properties of antibodies, receptors and enzymes while possessing higher durability. As such, these polymers are interesting materials for applications in biomimetic sensor, drug synthesis, drug delivery and separation. In this study, we prepared MIPs and molecularly imprinted nanospheres (MINs) as receptors with specific recognition properties toward tocopherol succinate (TPS) in comparison to tocopherol (TP) and tocopherol nicotinate (TPN). MIPs were synthesized using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinking agent and dichloromethane or acetronitrile as porogenic solvent under thermal-induced polymerization condition. Results indicated that imprinted polymers of TPS-MIP, TP-MIP and TPN-MIP all bound specifically to their template molecules at 2 folds greater than the non-imprinted polymers. The calculated binding capacity of all MIP was approximately 2 mg per gram of polymer when using the optimal rebinding solvent EtOH:H2O (3:2, v/v). Furthermore, the MINs toward TPS and TP were prepared by precipitation polymerization that yielded particles that are 200-400 nm in size. The binding capacities of MINs to their templates were greater than that of the non-imprinted nanospheres when using the optimal rebinding solvent EtOH:H2O (4:1, v/v). Computer simulation was performed to provide mechanistic insights on the binding modalities of template-monomer complexes. In conclusion, we had successful prepared MIPs and MINs for binding specifically to TP and TPS. Such MIPs and MINs have great potential for industrial and medical applications, particularly for the selective separation of TP and TPS. PMID:26622214

  7. Synthesis and computational investigation of molecularly imprinted nanospheres for selective recognition of alpha-tocopherol succinate.

    PubMed

    Piacham, Theeraphon; Nantasenamat, Chanin; Isarankura-Na-Ayudhya, Chartchalerm; Prachayasittikul, Virapong

    2013-01-01

    Molecularly imprinted polymers (MIPs) are macromolecular matrices that can mimic the functional properties of antibodies, receptors and enzymes while possessing higher durability. As such, these polymers are interesting materials for applications in biomimetic sensor, drug synthesis, drug delivery and separation. In this study, we prepared MIPs and molecularly imprinted nanospheres (MINs) as receptors with specific recognition properties toward tocopherol succinate (TPS) in comparison to tocopherol (TP) and tocopherol nicotinate (TPN). MIPs were synthesized using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinking agent and dichloromethane or acetronitrile as porogenic solvent under thermal-induced polymerization condition. Results indicated that imprinted polymers of TPS-MIP, TP-MIP and TPN-MIP all bound specifically to their template molecules at 2 folds greater than the non-imprinted polymers. The calculated binding capacity of all MIP was approximately 2 mg per gram of polymer when using the optimal rebinding solvent EtOH:H2O (3:2, v/v). Furthermore, the MINs toward TPS and TP were prepared by precipitation polymerization that yielded particles that are 200-400 nm in size. The binding capacities of MINs to their templates were greater than that of the non-imprinted nanospheres when using the optimal rebinding solvent EtOH:H2O (4:1, v/v). Computer simulation was performed to provide mechanistic insights on the binding modalities of template-monomer complexes. In conclusion, we had successful prepared MIPs and MINs for binding specifically to TP and TPS. Such MIPs and MINs have great potential for industrial and medical applications, particularly for the selective separation of TP and TPS.

  8. Ca(2+)-sensitive inhibition by Pb(2+) of alpha7-containing nicotinic acetylcholine receptors in hippocampal neurons.

    PubMed

    Mike, A; Pereira, E F; Albuquerque, E X

    2000-08-04

    In the present study the patch-clamp technique was applied to cultured hippocampal neurons to determine the kinetics as well as the agonist concentration- and Ca(2+)-dependence of Pb(2+)-induced inhibition of alpha7 nicotinic receptors (nAChRs). Evidence is provided that more than two-thirds of the inhibition by Pb(2+) (3-30 microM) of alpha7 nAChR-mediated whole-cell currents (referred to as type IA currents) develops rapidly and is fully reversible upon washing. The estimated values for tau(onset) and tau(recovery) were 165 and 240 ms, respectively. The magnitude of the effect of Pb(2+) was the same regardless of whether acetylcholine or choline was the agonist. Pre-exposure of the neurons for 800 ms to Pb(2+) (30 microM) decreased the amplitude and accelerated the decay phase of currents evoked by moderate to high agonist concentrations. In contrast, only the amplitude of currents evoked by low agonist concentrations was reduced when the neurons were exposed simultaneously to Pb(2+) and the agonists. Taken together with the findings that Pb(2+) reduces the frequency of opening and the mean open time of alpha7 nAChR channels, these data suggest that Pb(2+) accelerates the rate of receptor desensitization. An additional reduction of type IA current amplitudes occurred after 2-min exposure of the neurons to Pb(2+). This effect was not reversible upon washing of the neurons and was most likely due to an intracellular action of Pb(2+). Pb(2+)-induced inhibition of alpha7 nAChRs, which was hindered by the enhancement of extracellular Ca(2+) concentrations, may contribute to the neurotoxicity of the heavy metal.

  9. Effect of electrode material and design on sensitivity and selectivity for high temperature impedancemetric NOx sensors

    SciTech Connect

    Woo, L Y; Glass, R S; Novak, R F; Visser, J H

    2009-09-23

    Solid-state electrochemical sensors using two different sensing electrode compositions, gold and strontium-doped lanthanum manganite (LSM), were evaluated for gas phase sensing of NO{sub x} (NO and NO{sub 2}) using an impedance-metric technique. An asymmetric cell design utilizing porous YSZ electrolyte exposed both electrodes to the test gas (i.e., no reference gas). Sensitivity to less than 5 ppm NO and response/recovery times (10-90%) less than 10 s were demonstrated. Using an LSM sensing electrode, virtual identical sensitivity towards NO and NO{sub 2} was obtained, indicating that the equilibrium gas concentration was measured by the sensing electrode. In contrast, for cells employing a gold sensing electrode the NO{sub x} sensitivity varied depending on the cell design: increasing the amount of porous YSZ electrolyte on the sensor surface produced higher NO{sub 2} sensitivity compared to NO. In order to achieve comparable sensitivity for both NO and NO{sub 2}, the cell with the LSM sensing electrode required operation at a lower temperature (575 C) than the cell with the gold sensing electrode (650 C). The role of surface reactions are proposed to explain the differences in NO and NO{sub 2} selectivity using the two different electrode materials.

  10. Highly selective and sensitive fluorescent paper sensor for nitroaromatic explosive detection.

    PubMed

    Ma, Yingxin; Li, Hao; Peng, Shan; Wang, Leyu

    2012-10-02

    Rapid, sensitive, and selective detection of explosives such as 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP), especially using a facile paper sensor, is in high demand for homeland security and public safety. Although many strategies have been successfully developed for the detection of TNT, it is not easy to differentiate the influence from TNP. Also, few methods were demonstrated for the selective detection of TNP. In this work, via a facile and versatile method, 8-hydroxyquinoline aluminum (Alq(3))-based bluish green fluorescent composite nanospheres were successfully synthesized through self-assembly under vigorous stirring and ultrasonic treatment. These polymer-coated nanocomposites are not only water-stable but also highly luminescent. Based on the dramatic and selective fluorescence quenching of the nanocomposites via adding TNP into the aqueous solution, a sensitive and robust platform was developed for visual detection of TNP in the mixture of nitroaromatics including TNT, 2,4-dinitrotoluene (DNT), and nitrobenzene (NB). Meanwhile, the fluorescence intensity is proportional to the concentration of TNP in the range of 0.05-7.0 μg/mL with the 3σ limit of detection of 32.3 ng/mL. By handwriting or finger printing with TNP solution as ink on the filter paper soaked with the fluorescent nanocomposites, the bluish green fluorescence was instantly and dramatically quenched and the dark patterns were left on the paper. Therefore, a convenient and rapid paper sensor for TNP-selective detection was fabricated.

  11. Mechanical stimulation of skeletal muscle increases prostaglandin F2(alpha) synthesis and cyclooxygenase activity by a pertussis toxin sensitive mechanism

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.; Shansky, Janet; Solerssi, Rosa; Chromiak, Joseph

    1992-01-01

    Repetitive mechanical stimulation of differentiated skeletal muscle in tissue culture increases the production of prostaglandin F(sub 2(alpha)), an anabolic stimulator of myofiber growth. Within 4 h of initiating mechanical activity, the activity of cyclooxygenase, a regulatory enzyme in prostaglandin synthesis, was increased 82% (P is less than .005), and this increase was maintained for at least 24 h. Kinetic analysis of the stretch-activated cyclooxygenase indicated a two to three-fold decrease in the enzyme's K(sub m) with no change in V(sub max). The stretch-induced increase in enzymatic activity was not inhibited by cycloheximide, was independent of cellular electrical activity (tetrodotoxin-insensitive), but was prevented by the G protein inhibitor pertussis toxin. Pertussis toxin also inhibited the stretch-induced increases in PGF(sub 2(alpha)) production, and cell growth. It is concluded that stretch of skeletal muscle increases the synthesis of the anabolic modulator PGF(sub 2(alpha)) by a G protein-dependent process which involves activation of cyclooxygenase by a posttranslational mechanism.

  12. Implication of potassium trimolybdate nanowires as highly sensitive and selective ammonia sensor at room temperature

    NASA Astrophysics Data System (ADS)

    Joshi, Aditee C.; Gangal, S. A.

    2016-09-01

    Potassium trimolybdate nanowires are demonstrated as unique and highly selective NH3 sensing materials at room temperature. The nanowires were synthesized by using chemical route under normal ambient conditions and subsequently characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Gas sensors based on nanowires were fabricated by isolating and aligning nanowires between microspaced electrodes using dielectrophoresis. Room temperature gas sensing studies for different vapors indicated excellent selectivity for NH3 and capability to detect NH3 at concentrations down to ppb level. The sensors exhibited higher sensitivity for concentration range much below toxic limit of NH3 from 500 ppb up to 25 ppm. Since nanowires are isolated and aligned, the gas sensing reaction is rapid, and the availability of abundant oxide and hydroxyl surface groups on nanowires surface makes the reaction significantly prominent and selective with highly reducing nature of NH3.

  13. THE FIRST SYSTEMATIC SURVEY FOR Ly{alpha} EMITTERS AT z = 7.3 WITH RED-SENSITIVE SUBARU/SUPRIME-CAM

    SciTech Connect

    Shibuya, Takatoshi; Kashikawa, Nobunari; Iye, Masanori; Ota, Kazuaki; Ouchi, Masami; Furusawa, Hisanori; Shimasaku, Kazuhiro; Hattori, Takashi

    2012-06-20

    We have performed deep imaging surveys for Ly{alpha} emitters (LAEs) at redshift {approx}7.3 in two blank fields, the Subaru Deep Field (SDF) and the Subaru/XMM-Newton Deep survey Field (SXDF), using the Subaru/Suprime-Cam equipped with new red-sensitive CCDs and a new narrowband filter, NB1006 ({lambda}{sub c} = 10052 Angstrom-Sign , FWHM {Delta}{lambda} = 214 A). We identified four objects as LAE candidates that exhibit luminosity excess in NB1006. By carrying out deep follow-up spectroscopy for three of them using Subaru/FOCAS and Keck/DEIMOS, a definitively asymmetric emission line is detected for one of them, SXDF-NB1006-2. Assuming this line is Ly{alpha}, this object is an LAE at z = 7.215 which has a luminosity of 1.2{sup +1.5}{sub -0.6} Multiplication-Sign 10{sup 43} erg s{sup -1} and a weighted skewness S{sub {omega}} = 4.90 {+-} 0.86. Another object, SDF-NB1006-2, shows variable photometry and is thus probably a quasar (QSO) or an active galactic nucleus. It shows an asymmetric emission line at 10076 A which may be due to either Ly{alpha} at z = 7.288 or [O II] at z = 1.703. The third object, SDF-NB1006-1, is likely a galaxy with temporal luminosity enhancement associated with a supernova explosion, as the brightness of this object varies between the observed epochs. Its spectrum does not show any emission lines. The inferred decrease in the number density of LAEs toward higher redshift is n{sup z={sup {sup 7.3}{sub Ly{alpha}}}}/n{sub Ly{alpha}}{sup z={sup {sup 5.7}}} = 0.05{sup +0.11}{sub -0.05} from z = 5.7 to 7.3 down to L{sup Ly{alpha}} = 1.0 Multiplication-Sign 10{sup 43} erg s{sup -1}. The present result is consistent with the interpretation in previous studies that the neutral hydrogen fraction is rapidly increasing from z = 5.7 to 7.3.

  14. Depolarization Controls TRAIL-Sensitization and Tumor-Selective Killing of Cancer Cells: Crosstalk with ROS

    PubMed Central

    Suzuki-Karasaki, Yoshihiro; Suzuki-Karasaki, Miki; Uchida, Mayumi; Ochiai, Toyoko

    2014-01-01

    Conventional genotoxic anti-cancer drugs target the proliferative advantage of tumor cells over normal cells. This kind of approach lacks the selectivity of treatment to cancer cells, because most of the targeted pathways are essential for the survival of normal cells. As a result, traditional cancer treatments are often limited by undesirable damage to normal cells (side-effects). Ideal anti-cancer drugs are expected to be highly effective against malignant tumor cells with minimal cytotoxicity toward normal cells. Such selective killing can be achieved by targeting pathways essential for the survival of cancer cells, but not normal cells. As cancer cells are characterized by their resistance to apoptosis, selective apoptosis induction is a promising approach for selective killing of cancer cells. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising tumor-selective anti-cancer drug. However, the congenital and acquired resistance of some cancer cell types, including malignant melanoma cells, currently impedes effective TRAIL therapy, and an innovative approach that can override TRAIL resistance is urgently required. Apoptosis is characterized by cell shrinkage caused by disruption of the maintenance of the normal physiological concentrations of K+ and Na+ and intracellular ion homeostasis. The disrupted ion homeostasis leads to depolarization and apoptosis. Recent evidence suggests that depolarization is an early and prerequisite event during TRAIL-induced apoptosis. Moreover, diverse natural products and synthetic chemicals capable of depolarizing the cell membrane exhibit tumor-selective killing and TRAIL-sensitizing effects. Here, we discuss the role of depolarization in selective killing of cancer cells in connection with the emerging concept that oxidative stress is a critical mediator of mitochondrial and endoplasmic reticulum dysfunctions and serves as a tumor-selective target in cancer treatment. PMID:24910845

  15. Selective inhibition by chloramphenicol of pregnenolone-16. cap alpha. -carbonitrile-inducible rat liver cytochrome P-450 isozymes

    SciTech Connect

    Graves, P.E.; Kaminsky, L.S.; Halpert, J.

    1986-03-01

    Pregnenolone-16 ..cap alpha..-carbonitrile (PCN) has been shown to induce, in male rats, cytochrome P-450 isozymes responsible for the formation of R-10-hydroxywarfarin and R-dehydrowarfarin. Antibodies to the major PCN-inducible isozyme (PB/PCN-E) inhibit both activities in microsomal preparations. Recently the authors have shown that PCN treatment of female rats also induces the formation of both R-warfarin metabolites. However, in both sexes chloramphenicol (CAP) treatment selectively inhibits only the rate of formation of the R-dehydrowarfarin. A decrease in microsomal P-450 content occurs after in vivo administration of CAP to PCN-treated rats of both sexes. This is in contrast to the lack of effect of CAP on P-450 levels in phenobarbital-treated rats. Covalent binding of /sup 14/C-CAP to microsomal protein in vitro was increased 3 to 4-fold following PCN treatment. Chromatographic evidences suggests the presence of at least two PCN-induced isozymes of similar molecular weights in both male and female rat liver microsomes. These data are consistent with the multiplicity of PCN-inducible P-450 in rat liver.

  16. Optimizing Surveillance Performance of Alpha-Fetoprotein by Selection of Proper Target Population in Chronic Hepatitis B

    PubMed Central

    Chung, Jung Wha; Kim, Beom Hee; Lee, Chung Seop; Kim, Gi Hyun; Sohn, Hyung Rae; Min, Bo Young; Song, Joon Chang; Park, Hyun Kyung; Jang, Eun Sun; Yoon, Hyuk; Kim, Jaihwan; Shin, Cheol Min; Park, Young Soo; Hwang, Jin-Hyeok; Jeong, Sook-Hyang; Kim, Nayoung; Lee, Dong Ho; Lee, Jaebong; Ahn, Soyeon

    2016-01-01

    Although alpha-fetoprotein (AFP) is the most widely used biomarker in hepatocellular carcinoma (HCC) surveillance, disease activity may also increase AFP levels in chronic hepatitis B (CHB). Since nucleos(t)ide analog (NA) therapy may reduce not only HBV viral loads and transaminase levels but also the falsely elevated AFP levels in CHB, we tried to determine whether exposure to NA therapy influences AFP performance and whether selective application can optimize the performance of AFP testing in CHB during HCC surveillance. A retrospective cohort of 6,453 CHB patients who received HCC surveillance was constructed from the electronic clinical data warehouse. Covariates of AFP elevation were determined from 53,137 AFP measurements, and covariate-specific receiver operating characteristics regression analysis revealed that albumin levels and exposure to NA therapy were independent determinants of AFP performance. C statistics were largest in patients with albumin levels ≥ 3.7 g/dL who were followed without NA therapy during study period, whereas AFP performance was poorest when tested in patients with NA therapy during study and albumin levels were < 3.7 g/dL (difference in C statics = 0.35, p < 0.0001). Contrary to expectation, CHB patients with current or recent exposure to NA therapy showed poorer performance of AFP during HCC surveillance. Combination of concomitant albumin levels and status of NA therapy can identify subgroup of CHB patients who will show optimized AFP performance. PMID:27997559

  17. An alpha-mercaptoacrylic acid derivative is a selective nonpeptide cell-permeable calpain inhibitor and is neuroprotective.

    PubMed Central

    Wang, K K; Nath, R; Posner, A; Raser, K J; Buroker-Kilgore, M; Hajimohammadreza, I; Probert A, W; Marcoux, F W; Ye, Q; Takano, E; Hatanaka, M; Maki, M; Caner, H; Collins, J L; Fergus, A; Lee, K S; Lunney, E A; Hays, S J; Yuen, P

    1996-01-01

    Overactivation of calcium-activated neutral protease (calpain) has been implicated in the pathophysiology of several degenerative conditions, including stroke, myocardial ischemia, neuromuscular degeneration, and cataract formation. Alpha-mercaptoacrylate derivatives (exemplified by PD150606), with potent and selective inhibitory actions against calpain, have been identified. PD150606 exhibits the following characteristics: (i) Ki values for mu- and m-calpains of 0.21 microM and 0.37 microM, respectively, (ii) high specificity for calpains relative to other proteases, (iii) uncompetitive inhibition with respect to substrate, and (iv) it does not shield calpain against inactivation by the active-site inhibitor trans-(epoxysuccinyl)-L-leucyl-amido-3-methylbutane, suggesting a nonactive site action for PD150606. The recombinant calcium-binding domain from each of the large or small subunits of mu-calpain was found to interact with PD150606. In low micromolar range, PD15O6O6 inhibited calpain activity in two intact cell systems. The neuroprotective effects of this class of compound were also demonstrated by the ability of PD150606 to attenuate hypoxic/hypoglycemic injury to cerebrocortical neurons in culture and excitotoxic injury to Purkinje cells in cerebellar slices. Images Fig. 2 Fig. 4 Fig. 6 PMID:8692879

  18. Molecular imprinting ratiometric fluorescence sensor for highly selective and sensitive detection of phycocyanin.

    PubMed

    Wang, Xiaoyan; Yu, Jialuo; Kang, Qi; Shen, Dazhong; Li, Jinhua; Chen, Lingxin

    2016-03-15

    A facile strategy was developed to prepare molecular imprinting ratiometric fluorescence sensor for highly selective and sensitive detection of phycocyanin (PC) based on fluorescence resonance energy transfer (FRET), via a sol-gel polymerization process using nitrobenzoxadiazole (NBD) as fluorescent signal source. The ratio of two fluorescence peak emission intensities of NBD and PC was utilized to determine the concentration of PC, which could effectively reduce the background interference and fluctuation of diverse conditions. As a result, this sensor obtained high sensitivity with a low detection limit of 0.14 nM within 6 min, and excellent recognition specificity for PC over its analogues with a high imprinting factor of 9.1. Furthermore, the sensor attained high recoveries in the range of 93.8-110.2% at three spiking levels of PC, with precisions below 4.7% in seawater and lake water samples. The developed sensor strategy demonstrated simplicity, reliability, rapidity, high selectivity and high sensitivity, proving to be a feasible way to develop high efficient fluorescence sensors and thus potentially applicable for ultratrace analysis of complicated matrices.

  19. Sensitive and selective real-time electrochemical monitoring of DNA repair (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Slinker, Jason D.; McWilliams, Marc; Anka, Fadwa; Balkus, Kenneth

    2015-10-01

    Unrepaired DNA damage can lead to mutation, cancer, and death of cells or organisms. However, due to the subtlety of DNA damage, it is difficult to sense the repair of damage products with high selectivity and sensitivity. Here, we show sensitive and selective electrochemical sensing of the repair activity of 8-oxoguanine and uracil glycosylases within DNA monolayers on gold by multiplexed analysis with silicon chips and low-cost electrospun nanofibers. Our approach involves comparing the electrochemical signal of redox probe modified monolayers containing the defect versus the rational control of defect-free monolayers. We find sequence-specific sensitivity thresholds on the order of femtomoles of proteins and dynamic ranges of over two orders of magnitude for each target. For 8-oxoguanine repair, temperature-dependent kinetics are extracted, showing exponential signal loss with time constants of seconds. Electrospun fibers are shown to behave similarly to conventional gold-on-silicon devices, showing the potential of these low-cost devices for sensing applications.

  20. Advancing the sensitivity of selected reaction monitoring-based targeted quantitative proteomics

    SciTech Connect

    Shi, Tujin; Su, Dian; Liu, Tao; Tang, Keqi; Camp, David G.; Qian, Weijun; Smith, Richard D.

    2012-04-01

    Selected reaction monitoring (SRM)—also known as multiple reaction monitoring (MRM)—has emerged as a promising high-throughput targeted protein quantification technology for candidate biomarker verification and systems biology applications. A major bottleneck for current SRM technology, however, is insufficient sensitivity for e.g., detecting low-abundance biomarkers likely present at the pg/mL to low ng/mL range in human blood plasma or serum, or extremely low-abundance signaling proteins in the cells or tissues. Herein we review recent advances in methods and technologies, including front-end immunoaffinity depletion, fractionation, selective enrichment of target proteins/peptides or their posttranslational modifications (PTMs), as well as advances in MS instrumentation, which have significantly enhanced the overall sensitivity of SRM assays and enabled the detection of low-abundance proteins at low to sub- ng/mL level in human blood plasma or serum. General perspectives on the potential of achieving sufficient sensitivity for detection of pg/mL level proteins in plasma are also discussed.

  1. Crystal Structures of Trypanosoma brucei Sterol 14[alpha]-Demethylase and Implications for Selective Treatment of Human Infections

    SciTech Connect

    Lepesheva, Galina I.; Park, Hee-Won; Hargrove, Tatiana Y.; Vanhollebeke, Benoit; Wawrzak, Zdzislaw; Harp, Joel M.; Sundaramoorthy, Munirathinam; Nes, W. David; Pays, Etienne; Chaudhuri, Minu; Villalta, Fernando; Waterman, Michael R.

    2010-01-25

    Sterol 14{alpha}-demethylase (14DM, the CYP51 family of cytochrome P450) is an essential enzyme in sterol biosynthesis in eukaryotes. It serves as a major drug target for fungal diseases and can potentially become a target for treatment of human infections with protozoa. Here we present 1.9 {angstrom} resolution crystal structures of 14DM from the protozoan pathogen Trypanosoma brucei, ligand-free and complexed with a strong chemically selected inhibitor N-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl-4-(5-phenyl-1,3,4-oxadi-azol-2-yl)benzamide that we previously found to produce potent antiparasitic effects in Trypanosomatidae. This is the first structure of a eukaryotic microsomal 14DM that acts on sterol biosynthesis, and it differs profoundly from that of the water-soluble CYP51 family member from Mycobacterium tuberculosis, both in organization of the active site cavity and in the substrate access channel location. Inhibitor binding does not cause large scale conformational rearrangements, yet induces unanticipated local alterations in the active site, including formation of a hydrogen bond network that connects, via the inhibitor amide group fragment, two remote functionally essential protein segments and alters the heme environment. The inhibitor binding mode provides a possible explanation for both its functionally irreversible effect on the enzyme activity and its selectivity toward the 14DM from human pathogens versus the human 14DM ortholog. The structures shed new light on 14DM functional conservation and open an excellent opportunity for directed design of novel antiparasitic drugs.

  2. Long-observation-window band-selective homonuclear decoupling: Increased sensitivity and resolution in solid-state NMR spectroscopy of proteins

    NASA Astrophysics Data System (ADS)

    Struppe, Jochem O.; Yang, Chen; Wang, Yachong; Hernandez, Roy V.; Shamansky, Lisa M.; Mueller, Leonard J.

    2013-11-01

    Sensitivity and resolution are the two fundamental obstacles to extending solid-state nuclear magnetic resonance to even larger protein systems. Here, a novel long-observation-window band-selective homonuclear decoupling (LOW BASHD) scheme is introduced that increases resolution up to a factor of 3 and sensitivity up to 1.8 by decoupling backbone alpha-carbon (Cα) and carbonyl (C‧) nuclei in U-13C-labeled proteins during direct 13C acquisition. This approach introduces short (<200 μs) pulse breaks into much longer (˜8 ms) sampling windows to efficiently refocus the J-coupling interaction during detection while avoiding the deleterious effects on sensitivity inherent in rapid stroboscopic band-selective homonuclear decoupling techniques. A significant advantage of LOW-BASHD detection is that it can be directly incorporated into existing correlation methods, as illustrated here for 2D CACO, NCO, and NCA correlation spectroscopy applied to the β1 immunoglobulin binding domain of protein G and 3D CBCACO correlation spectroscopy applied to the α-subunit of tryptophan synthase.

  3. Dihydropyridine-sensitive calcium channels in cardiac and skeletal muscle membranes: studies with antibodies against the. cap alpha. subunits

    SciTech Connect

    Takahashi, M.; Catterall, W.A.

    1987-08-25

    Polyclonal antibodies (PAC-2) against the purified skeletal muscle calcium channel were prepared and shown to be directed against ..cap alpha.. subunits of this protein by immunoblotting and immunoprecipitation. These polypeptides have an apparent molecular weight of 162,000 without reduction of disulfide bonds. Under conditions where the functional properties of the purified skeletal muscle calcium channel are retained, ..beta.. subunits (M/sub r/ 50,000) and lambda subunits (M/sub r/ 33,000) are coprecipitated, demonstrating specific noncovalent association of these three polypeptides in the purified skeletal muscle channel. PAC-2 immunoprecipitated cardiac calcium channels labeled with (/sup 3/H)isopropyl 4-(2,1,3-benzoxadiazol-4-yl)-1,4-dihydro-2,6-dimethyl-5-(methoxycarbonyl)pyridine-3-carboxylate ((/sup 3/H)PN200-110) at a 3-fold higher concentration than skeletal muscle channels. Preincubation with cardiac calcium channels blocked only 49% of the immunoreactivity of PAC-2 toward skeletal muscle channels, indicating that these two proteins have both homologous and distinct epitopes. The immunoreactive component of the cardiac calcium channel was identified by immunoprecipitation and polyacrylamide gel electrophoresis as a polypeptide with an apparent molecular weight of 170,000 before reduction of disulfide bonds and 141,000 after reduction, in close analogy with the properties of the ..cap alpha../sub 2/ subunits of the skeletal muscle channel. The calcium channels were radiolabeled with /sup 32/P and /sup 125/I. It is concluded that these two calcium channels have a homologous, but distinct, ..cap alpha.. subunit as a major polypeptide component.

  4. Dehydroepiandrosterone decreases serum tumor necrosis factor-alpha and restores insulin sensitivity: independent effect from secondary weight reduction in genetically obese Zucker fatty rats.

    PubMed

    Kimura, M; Tanaka, S; Yamada, Y; Kiuchi, Y; Yamakawa, T; Sekihara, H

    1998-07-01

    Dehydroepiandrosterone (DHEA) and its sulfate ester are the most abundant circulating adrenal steroids in humans. Administration of DHEA has been reported to have beneficial effects on obesity, hyperlipidemia, diabetes, and atherosclerosis in obese rodents, although its effects on insulin resistance have not been fully elucidated. In this study, the effects of DHEA treatment on insulin sensitivity were investigated in genetically obese Zucker rats, an animal model of insulin resistance, using the euglycemic clamp technique. After 0.4% DHEA was administered for 10 days to female obese Zucker rats aged 16 weeks, body weight and plasma insulin decreased and glucose disposal rate (GDR), which was normally reduced in obese rats, rose significantly compared with age- and sex-matched control obese rats. On the other hand, although the pair-fed obese rats also showed levels of weight reduction similar to those of DHEA-treated rats, the increase in GDR of DHEA-treated rats was significantly greater than in pair-fed rats, suggesting a direct ameliorating effect of DHEA on insulin sensitivity of obese rats. Serum concentration of tumor necrosis factor (TNF)-alpha, one of cytokines causing insulin resistance, was also reduced significantly in DHEA-treated, but not in pair-fed obese rats. In conclusion, our results suggest that DHEA treatment reduces body weight and serum TNF-alpha independently, and that both may ameliorate insulin resistance in obese Zucker fatty rats.

  5. A Catalytic Beacon Sensor for Uranium with Parts-per-Trillion Sensitivity and Millionfold Selectivity

    SciTech Connect

    Liu, Juewen; Brown, Andrea K.; Meng, Xiangli; Cropek, Donald M.; IstokD., Jonathan; Watson, David B; Liu, Yi

    2007-01-01

    Here, we report a catalytic beacon sensor for uranyl (UO{sub 2}{sup 2+}) based on an in vitro-selected UO{sub 2}{sup 2+}-specific DNAzyme. The sensor consists of a DNA enzyme strand with a 3' quencher and a DNA substrate with a ribonucleotide adenosine (rA) in the middle and a fluorophore and a quencher at the 5' and 3' ends, respectively. The presence of UO{sub 2}{sup 2+} causes catalytic cleavage of the DNA substrate strand at the rA position and release of the fluorophore and thus dramatic increase of fluorescence intensity. The sensor has a detection limit of 11 parts per trillion (45 pM), a dynamic range up to 400 nM, and selectivity of >1-million-fold over other metal ions. The most interfering metal ion, Th(IV), interacts with the fluorescein fluorophore, causing slightly enhanced fluorescence intensity, with an apparent dissociation constant of {approx}230 {micro}M. This sensor rivals the most sensitive analytical instruments for uranium detection, and its application in detecting uranium in contaminated soil samples is also demonstrated. This work shows that simple, cost-effective, and portable metal sensors can be obtained with similar sensitivity and selectivity as much more expensive and sophisticated analytical instruments. Such a sensor will play an important role in environmental remediation of radionuclides such as uranium.

  6. Highly sensitive and selective sugar detection by terahertz nano-antennas.

    PubMed

    Lee, Dong-Kyu; Kang, Ji-Hun; Lee, Jun-Seok; Kim, Hyo-Seok; Kim, Chulki; Kim, Jae Hun; Lee, Taikjin; Son, Joo-Hiuk; Park, Q-Han; Seo, Minah

    2015-10-23

    Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz (THz) frequency range (0.5-2.5 THz). This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz transmission by nano-antennas can effectively increase the molecular absorption cross sections, thereby enabling the detection of these molecules even at low concentrations. We verified the performance of nano-antenna sensing chip by both THz spectra and images of transmittance. Screening and identification of various carbohydrates can be applied to test even real market beverages with a high sensitivity and selectivity.

  7. Highly sensitive and selective sugar detection by terahertz nano-antennas

    PubMed Central

    Lee, Dong-Kyu; Kang, Ji-Hun; Lee, Jun-Seok; Kim, Hyo-Seok; Kim, Chulki; Hun Kim, Jae; Lee, Taikjin; Son, Joo-Hiuk; Park, Q-Han; Seo, Minah

    2015-01-01

    Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz (THz) frequency range (0.5–2.5 THz). This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz transmission by nano-antennas can effectively increase the molecular absorption cross sections, thereby enabling the detection of these molecules even at low concentrations. We verified the performance of nano-antenna sensing chip by both THz spectra and images of transmittance. Screening and identification of various carbohydrates can be applied to test even real market beverages with a high sensitivity and selectivity. PMID:26494203

  8. Highly sensitive and selective sugar detection by terahertz nano-antennas

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Kyu; Kang, Ji-Hun; Lee, Jun-Seok; Kim, Hyo-Seok; Kim, Chulki; Hun Kim, Jae; Lee, Taikjin; Son, Joo-Hiuk; Park, Q.-Han; Seo, Minah

    2015-10-01

    Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz (THz) frequency range (0.5-2.5 THz). This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz transmission by nano-antennas can effectively increase the molecular absorption cross sections, thereby enabling the detection of these molecules even at low concentrations. We verified the performance of nano-antenna sensing chip by both THz spectra and images of transmittance. Screening and identification of various carbohydrates can be applied to test even real market beverages with a high sensitivity and selectivity.

  9. Fast picomolar selective detection of bisphenol A in water using a carbon nanotube field effect transistor functionalized with estrogen receptor-alpha.

    PubMed

    Sánchez-Acevedo, Zayda C; Riu, Jordi; Rius, F Xavier

    2009-05-15

    In this paper we report a biosensor for the fast, ultrasensitive and selective determination of bisphenol A in water. It is based on a field effect transistor (FET) in which a network of single-walled carbon nanotubes (SWCNTs) acts as the conductor channel. SWCNTs are functionalized for the first time with a nuclear receptor, the estrogen receptor alpha (ER-alpha), which is adsorbed onto the SWCNTs and acts as the sensing part of the biosensor. SWCTNs are subsequently protected to prevent the non-specific binding of interferences. With this biosensor we can detect picomolar concentrations of BPA in only 2 min of analysis. Selectivity has been tested against possible interferences such as fluoranthene, pentacloronitrobenzene and malathion, and this is the first device that experimentally shows that small molecules can also be selectively detected at ultralow concentrations using a CNTFET biosensor.

  10. Measurement of 2J(H,C)- and 3J(H,C)-coupling constants by alpha/beta selective HC(C)H-TOCSY.

    PubMed

    Duchardt, E; Richter, C; Reif, B; Glaser, S J; Engels, J W; Griesinger, C; Schwalbe, H

    2001-10-01

    A new heteronuclear NMR pulse sequence for the measurement of nJ(C,H) coupling constants, the alpha/beta selective HC(C)H-TOCSY, is described. It is shown that the S3E element (Meissner et al., 1997a,b) can be used to obtain spin state selective coherence transfer in molecules, in which adjacent CH moieties are labeled with 13C. Application of the alpha/beta selective HC(C)H-TOCSY to a 10 nt RNA tetraloop 5'-CGCUUUUGCG-3', in which the four uridine residues are 13C labeled in the sugar moiety, allowed measurement of two bond and three bond J(C,H) coupling constants, which provide additional restraints to characterize the sugar ring conformation of RNA in cases of conformational averaging.

  11. Highly sensitive and selective odorant sensor using living cells expressing insect olfactory receptors

    PubMed Central

    Misawa, Nobuo; Mitsuno, Hidefumi; Kanzaki, Ryohei; Takeuchi, Shoji

    2010-01-01

    This paper describes a highly sensitive and selective chemical sensor using living cells (Xenopus laevis oocytes) within a portable fluidic device. We constructed an odorant sensor whose sensitivity is a few parts per billion in solution and can simultaneously distinguish different types of chemicals that have only a slight difference in double bond isomerism or functional group such as ─OH, ─CHO and ─C(═O)─. We developed a semiautomatic method to install cells to the fluidic device and achieved stable and reproducible odorant sensing. In addition, we found that the sensor worked for multiple-target chemicals and can be integrated with a robotic system without any noise reduction systems. Our developed sensor is compact and easy to replace in the system. We believe that the sensor can potentially be incorporated into a portable system for monitoring environmental and physical conditions. PMID:20798064

  12. Sensitive and selective detection of copper ions with highly stable polyethyleneimine-protected silver nanoclusters.

    PubMed

    Yuan, Zhiqin; Cai, Na; Du, Yi; He, Yan; Yeung, Edward S

    2014-01-07

    Copper is a highly toxic environmental pollutant with bioaccumulative properties. Therefore, sensitive Cu(2+) detection is very important to prevent over-ingestion, and visual detection using unaugmented vision is preferred for practical applications. In this study, hyperbranched polyethyleneimine-protected silver nanoclusters (hPEI-AgNCs) were successfully synthesized using a facile, one-pot reaction under mild conditions. The hPEI-AgNCs were very stable against extreme pH, ionic strength, temperature, and photoillumination and could act as sensitive and selective Cu(2+) sensing nanoprobes in aqueous solutions with a 10 nM limit of detection. In addition, hPEI-AgNCs-doped agarose hydrogels were developed as an instrument-free and regenerable platform for visual Cu(2+) and water quality monitoring.

  13. Sensitive hydrogen sensor based on selectively infiltrated photonic crystal fiber with Pt-loaded WO₃ coating.

    PubMed

    Wang, Ying; Wang, D N; Yang, Fan; Li, Zhi; Yang, Minghong

    2014-07-01

    A sensitive hydrogen sensing device based on a selectively infiltrated photonic crystal fiber (PCF) coated with Pt-loaded WO₃ is demonstrated. With Pt-loaded WO₃ coating acting as the catalytic layer, hydrogen undergoes an exothermic reaction with oxygen and releases heat when the device is exposed to gas mixtures of air and hydrogen, which induces local temperature change in the PCF and hence leads to the resonant wavelength shift of the proposed device. The maximum wavelength shift of 98.5 nm is obtained with a 10-mm-long infiltrated PCF for 4% (v/v) H₂ concentration, and a hydrogen sensitivity of 32.3 nm/% (v/v) H₂ is achieved within the range of 1%-4% (v/v) H₂ in air.

  14. Highly Sensitive and Selective Gas Sensor Using Hydrophilic and Hydrophobic Graphenes

    PubMed Central

    Some, Surajit; Xu, Yang; Kim, Youngmin; Yoon, Yeoheung; Qin, Hongyi; Kulkarni, Atul; Kim, Taesung; Lee, Hyoyoung

    2013-01-01

    New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor. PMID:23736838

  15. Leveraging zinc interstitials and oxygen vacancies for sensitive biomolecule detection through selective surface functionalization

    NASA Astrophysics Data System (ADS)

    Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Chaudhry, Shajee; Prasad, Shalini

    2015-03-01

    In this study, functionally engineered EIS technique was implemented to investigate the influence of surface functionalization on sensitivity of biomolecule detection using nanostructured ZnO platform. Organic molecules with thiol and carboxylic functional groups were chosen to control biomolecule immobilization on zinc and oxygen-terminated 2D planar and 1D nanostructured ZnO surfaces. The amount of functionalization and its influence on charge perturbations at the ZnO-electrolyte interface were studied using fluorescence and EIS measurements. We observed the dependence of charge transfer on both the polarity of platform and concentration of cross-linker molecules. Such selectively modified surfaces were used for detection of cortisol, a major stress indicator. Results demonstrated preferential binding of thiol groups to Zn terminations and thus leveraging ZnO interstitials increases the sensitivity of detection over larger dynamic range with detection limit at 10fg/mL.

  16. Opioid sensitivity in mice selectively bred to consume or not consume methamphetamine.

    PubMed

    Eastwood, Emily C; Phillips, Tamara J

    2014-05-01

    There has been little investigation of genetic factors and associated mechanisms that influence risk for development of methamphetamine (MA) dependence. Selectively bred mouse lines that exhibit high (MAHDR) or low (MALDR) levels of MA intake in a two-bottle choice MA drinking (MADR) procedure provide a genetic tool for this purpose. These lines were used to determine whether opioid sensitivity and MA intake are genetically associated, because opioid-mediated pathways influence some effects of MA. Sensitivity to the analgesic effects of the μ-opioid receptor (MOP-r) agonist fentanyl (0.05, 0.1, 0.2, 0.4 mg/kg) was examined using two acute thermal tests (hot plate and tail flick) and one chronic pain test (magnesium sulfate abdominal constriction). Locomotor stimulant responses to fentanyl (0.05, 0.1, 0.2, 0.4 mg/kg) and morphine (10, 20, 30 mg/kg) were also examined. In addition, MADR was measured in the progenitor strains [(C57BL/6J (B6), DBA/2J (D2)] of the F2 population from which the selected lines were generated. The MADR lines did not differ in sensitivity to the analgesic effects of fentanyl; however, MALDR mice exhibited greater locomotor activation than MAHDR mice to both fentanyl and morphine. D2 mice consumed more MA than B6 mice. The line differences for MA consumption and morphine activation recapitulated B6 and D2 strain differences for these two traits, but not strain differences previously found for opioid analgesic responses. These results support a negative genetic correlation between MA consumption and sensitivity to the stimulant effects of opioids and suggest the involvement of MOP-r regulated systems in MA intake.

  17. Sensitive and selective colorimetric assay of alkaline phosphatase activity with Cu(II)-phenanthroline complex.

    PubMed

    Hu, Qiong; He, Minhui; Mei, Yaqi; Feng, Wenjie; Jing, Su; Kong, Jinming; Zhang, Xueji

    2017-01-15

    Alkaline phosphatase (ALP) plays a vital role in dephosphorylation- and phosphorylation-related cellular regulation and signaling processes. Accordingly, the development of efficient methods for ALP activity assay is of significant importance in clinical diagnosis. In this work, a simple and practical method is reported for the first time for the sensitive and selective colorimetric assay of ALP activity by exploiting a water-soluble Cu(II)-phenanthroline complex as the probe, on the basis of the distinctive metal-to-ligand charge-transfer (MLCT) properties. This method is simply built on a two-step chromogenic reaction: the enzymatic hydrolysis of the substrate ascorbic acid 2-phosphate to ascorbic acid (AA), followed by the reduction of the colorimetric probe Cu(BPDS)2(2-) (BPDS=bathophenanthroline disulfonate) by AA to its cuprous form. The latter process triggers a turn-on spectral absorption at 424nm and a striking color change of the solution from colorless to blackish-green. Needless of complicated protocols and instrumentation, this method allows a sensitive readout of ALP activity within a wide linear range of 0-200mUmL(-)(1), with a detection limit down to 1.25mUmL(-1). Results also reveal that it is highly selective and holds great potential in ALP inhibitor efficiency evaluation. In addition, quantitative analysis of ALP activity in spiked serum samples has been realized successfully in the linear range of 0-200mUmL(-1), with a detection limit of 1.75mUmL(-1). Advantages of simplicity, wide linear range, high sensitivity and selectivity, low cost, and little background interference render this method great potential in practical applications.

  18. Selective and sensitive detection of chromium(VI) in waters using electrospray ionization mass spectrometry.

    PubMed

    Weldy, Effie; Wolff, Chloe; Miao, Zhixin; Chen, Hao

    2013-09-01

    From 2000 through 2011, there were 14 criminal cases of violations of the Clean Water Act involving the discharge of chromium, a toxic heavy metal, into drinking and surface water sources. As chromium(VI), a potential carcinogen present in the environment, represents a significant safety concern, it is currently the subject of an EPA health risk assessment. Therefore, sensitive and selective detection of this species is highly desired. This study reports the analysis of chromium(VI) in water samples by electrospray ionization mass spectrometry (ESI-MS) following its reduction and complexation with ammonium pyrrolidinedithiocarbamate (APDC). The reduction and subsequent complexation produce a characteristic [Cr(III)O]-PDC complex which can be detected as a protonated ion of m/z 507 in the positive ion mode. The detection is selective to chromium(VI) under acidic pH, even in the presence of chromium(III) and other metal ions, providing high specificity. Different water samples were examined, including deionized, tap, and river waters, and sensitive detection was achieved. In the case of deionized water, quantification over the concentration range of 3.7 to 148ppb gave an excellent correlation coefficient of 0.9904 using the enhanced MS mode scan. Using the single-reaction monitoring (SRM) mode (monitoring the characteristic fragmentation of m/z 507 to m/z 360), the limit of detection (LOD) was found to be 0.25ppb. The LOD of chromium(VI) for both tap and river water samples was determined to be 2.0ppb. A preconcentration strategy using simple vacuum evaporation of the aqueous sample was shown to further improve the ESI signal by 15 fold. This method, with high sensitivity and selectivity, should provide a timely solution for the real-world analysis of toxic chromium(VI).

  19. Analogs of alpha-melanocyte stimulating hormone with high agonist potency and selectivity at human melanocortin receptor 1b: the role of Trp(9) in molecular recognition.

    PubMed

    Bednarek, Maria A; Macneil, Tanya; Tang, Rui; Fong, Tung M; Angeles Cabello, M; Maroto, Marta; Teran, Ana

    2008-05-01

    alpha-Melanocyte stimulating hormone (alphaMSH), Ac-Ser(1)-Tyr(2)-Ser(3)-Met(4)-Glu(5)-His(6)-Phe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH(2), is an endogenous agonist for the melanocortin receptor 1 (MC1R), the receptor found in the skin, several types of immune cells, and other peripheral sites. Three-dimensional models of complexes of this receptor with alphaMSH and its synthetic analog NDP-alphaMSH, Ac-Ser(1)-Tyr(2)-Ser(3)-Nle(4)-Glu(5)-His(6)-D-Phe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH(2), have been previously proposed. In those models, the 6-9 segment of the ligand was considered essential for the ligand-receptor interactions. In this study, we probed the role of Trp(9) of NDP-alphaMSH in interactions with hMC1bR. Analogs of NDP-alphaMSH with various amino acids in place of Trp(9) were synthesized and tested in vitro in receptor affinity binding and cAMP functional assays at human melanocortin receptors 1b, 3, 4, and 5 (hMC1b,3-5R). Several new compounds displayed high agonist potency at hMC1bR (EC(50) = 0.5-5 nM) and receptor subtype selectivity greater than 2000-fold versus hMC3-5R. The Trp(9) residue of NDP-alphaMSH was determined to be not essential for molecular recognition at hMC1bR.

  20. Cheat sensitive quantum bit commitment via pre- and post-selected quantum states

    NASA Astrophysics Data System (ADS)

    Li, Yan-Bing; Wen, Qiao-Yan; Li, Zi-Chen; Qin, Su-Juan; Yang, Ya-Tao

    2014-01-01

    Cheat sensitive quantum bit commitment is a most important and realizable quantum bit commitment (QBC) protocol. By taking advantage of quantum mechanism, it can achieve higher security than classical bit commitment. In this paper, we propose a QBC schemes based on pre- and post-selected quantum states. The analysis indicates that both of the two participants' cheat strategies will be detected with non-zero probability. And the protocol can be implemented with today's technology as a long-term quantum memory is not needed.

  1. A Sensitive Ratiometric Fluorescent Sensor for Zinc(II) with High Selectivity

    PubMed Central

    Lv, Yuanyuan; Cao, Mingda; Li, Jiakai; Wang, Junbo

    2013-01-01

    A new fluorescent Zn2+ chemosensor (P1) based on a functionalized porphyrin was synthesized and characterized. P1 displayed dramatic ratiometric variations in absorption and fluorescent emission spectra upon exposure to Zn2+ due to the formation of a 1:1 Zn2+/P1 complex. The sensor also exhibited high selectivity and sensitivity toward Zn2+ over other common metal ions in the physiological pH range with a detection limit of 1.8 μM. The sensor showed fast response times and excellent reproducibility, thus confirming its potential applicability as a fluorescent sensor for Zn2+ sensing. PMID:23467028

  2. ZnO thin film transistor immunosensor with high sensitivity and selectivity

    NASA Astrophysics Data System (ADS)

    Reyes, Pavel Ivanoff; Ku, Chieh-Jen; Duan, Ziqing; Lu, Yicheng; Solanki, Aniruddh; Lee, Ki-Bum

    2011-04-01

    A zinc oxide thin film transistor-based immunosensor (ZnO-bioTFT) is presented. The back-gate TFT has an on-off ratio of 108 and a threshold voltage of 4.25 V. The ZnO channel surface is biofunctionalized with primary monoclonal antibodies that selectively bind with epidermal growth factor receptor (EGFR). Detection of the antibody-antigen reaction is achieved through channel carrier modulation via pseudo double-gating field effect caused by the biochemical reaction. The sensitivity of 10 fM detection of pure EGFR proteins is achieved. The ZnO-bioTFT immunosensor also enables selectively detecting 10 fM of EGFR in a 5 mg/ml goat serum solution containing various other proteins.

  3. Cyclic analogs of alpha-melanocyte-stimulating hormone (alphaMSH) with high agonist potency and selectivity at human melanocortin receptor 1b.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Cabello, M Angeles; Maroto, Marta; Teran, Ana

    2008-06-01

    Alpha-melanotropin (alphaMSH), Ac-Ser1-Tyr2-Ser3-Met4-Glu5-His6-Phe7-Arg8-Trp9-Gly10-Lys11-Pro12-Val13-NH2,(1) has been long recognized as an important physiological regulator of skin and hair pigmentation in mammals. Binding of this peptide to the melanocortin receptor 1 (MC1R) leads to activation of tyrosinase, the key enzyme of the melanin biosynthesis pathway. In this study, interactions of the human MC1bR (an isoform of the receptor 1a) with the synthetic cyclic analogs of alphaMSH were studied. These ligands were analogs of MTII, Ac-Nle4-cyclo-(Asp5-His6-D-Phe7-Arg8-Trp9-Lys10)-NH2, a potent pan-agonist at the human melanocortin receptors (hMC1,3-5R). In the structure of MTII, the His6-D-Phe7-Arg8-Trp9 segment has been recognized as "essential" for molecular recognition at the human melanocortin receptors (hMC1,3-5R). Herein, the role of the Trp9 in the ligand interactions with the hMC1b,3-5R has been reevaluated. Analogs with various amino acids in place of Trp9 were synthesized and tested in vitro in receptor affinity binding and cAMP functional assays at human melanocortin receptors 1b, 3, 4 and 5 (hMC1b,3-5R). Several of the new peptides were high potency agonists (partial) at hMC1bR (EC50 from 0.5 to 20 nM) and largely inactive at hMC3-5R. The bulky aromatic side chain in position 9, such as that in Trp, was found not to be essential to agonism (partial) of the studied peptides at hMC1bR.

  4. Sensitivity- and effort-gain analysis: multilead ECG electrode array selection for activation time imaging.

    PubMed

    Hintermüller, Christoph; Seger, Michael; Pfeifer, Bernhard; Fischer, Gerald; Modre, Robert; Tilg, Bernhard

    2006-10-01

    Methods for noninvasive imaging of electric function of the heart might become clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as an easy and fast application. In this paper, we propose a new electrode array which improves the resolution of methods for activation time imaging considering clinical constraints such as easy to apply and compatibility with routine leads. For identifying the body-surface regions where the body surface potential (BSP) is most sensitive to changes in transmembrane potential (TMP), a virtual array method was used to compute local linear dependency (LLD) maps. The virtual array method computes a measure for the LLD in every point on the body surface. The most suitable number and position of the electrodes within the sensitive body surface regions was selected by constructing effort gain (EG) plots. Such a plot depicts the relative attainable rank of the leadfield matrix in relation to the increase in number of electrodes required to build the electrode array. The attainable rank itself was computed by a detector criterion. Such a criterion estimates the maximum number of source space eigenvectors not covered by noise when being mapped to the electrode space by the leadfield matrix and recorded by a detector. From the sensitivity maps, we found that the BSP is most sensitive to changes in TMP on the upper left frontal and dorsal body surface. These sensitive regions are covered best by an electrode array consisting of two L-shaped parts of approximately 30 cm x 30 cm and approximately 20 cm x 20 cm. The EG analysis revealed that the array meeting clinical requirements best and improving the resolution of activation time imaging consists of 125 electrodes with a regular horizontal and vertical spacing of 2-3 cm.

  5. Thyroid receptor ligands. Part 8: Thyromimetics derived from N-acylated-alpha-amino acid derivatives displaying modulated pharmacological selectivity compared with KB-141.

    PubMed

    Garg, Neeraj; Li, Yi-Lin; Garcia Collazo, Ana Maria; Litten, Chris; Ryono, Denis E; Zhang, Minsheng; Caringal, Yolanda; Brigance, Robert P; Meng, Wei; Washburn, William N; Agback, Peter; Mellström, Karin; Rehnmark, Stefan; Rahimi-Ghadim, Mahmoud; Norin, Thomas; Grynfarb, Marlena; Sandberg, Johnny; Grover, Gary; Malm, Johan

    2007-08-01

    Based on the scaffold of the pharmacologically selective thyromimetic 2b, structurally a close analog to KB-141 (2a), a number of novel N-acylated-alpha-amino acid derivatives were synthesized and tested in a TR radioligand binding assay as well as in a reporter cell assay. On the basis of TRbeta(1)-isoform selectivity and affinity, as well as affinity to the reporter cell assay, 3d was selected for further studies in the cholesterol-fed rat model. In this model 3d revealed an improved therapeutic window between cholesterol and TSH lowering but decreased margins versus tachycardia compared with 2a.

  6. Sensitization of vascular smooth muscle cell to TNF-{alpha}-mediated death in the presence of palmitate

    SciTech Connect

    Rho, Mun-Chual; Ah Lee, Kyeong; Mi Kim, Sun; Sik Lee, Chang; Jeong Jang, Min; Kook Kim, Young; Sun Lee, Hyun; Hyun Choi, Yung; Yong Rhim, Byung; Kim, Koanhoi . E-mail: koanhoi@pusan.ac.kr

    2007-05-01

    Saturated free fatty acids (FFAs), including palmitate, can activate the intrinsic death pathway in cells. However, the relationship between FFAs and receptor-mediated death pathway is still unknown. In this study, we have investigated whether FFAs are able to trigger receptor-mediated death. In addition, to clarify the mechanisms responsible for the activation, we examined the biochemical changes in dying vascular smooth muscle cell (VSMC) and the effects of various molecules to the receptor-mediated VSMC death. Tumor necrosis factor (TNF)-{alpha}-mediated VSMC death occurred in the presence of sub-cytotoxic concentration of palmitate as determined by assessing viability and DNA degradation, while the cytokine did not influence VSMC viability in the presence of oleate. The VSMC death was inhibited by the gene transfer of a dominant-negative Fas-associated death domain-containing protein and the baculovirus p35, but not by the bcl-xL or the c-Jun N-terminal kinase (JNK) binding domain of JNK-interacting protein-1, in tests utilizing recombinant adenoviruses. The VSMC death was also inhibited by a neutralizing anti-TNF receptor 1 antibody, the caspase inhibitor z-VAD, and the cathepsin B inhibitor CA074, a finding indicative of the role of both caspases and cathepsin B in this process. Consistent with this finding, caspase-3 activation and an increase in cytosolic cathepsin B activity were detected in the dying VSMC. Palmitate inhibited an increase of TNF-{alpha}-mediated nuclear factor kappa B (NF-{kappa}B) activity, the survival pathway activated by the cytokine, by hindering the translocation of the NF-{kappa}B subunit of p65 from the cytosol into the nucleus. The gene transfer of inhibitor of NF-{kappa}B predisposed VSMC to palmitate-induced cell death. To the best of our knowledge, this study is the first report to demonstrate the activation of TNF-{alpha}-mediated cell death in the presence of palmitate. The current study proposes that FFAs would take part in

  7. Selection of infectious medical waste disposal firms by using the analytic hierarchy process and sensitivity analysis

    SciTech Connect

    Hsu, P.-F. Wu, C.-R. Li, Y.-T.

    2008-07-01

    While Taiwanese hospitals dispose of large amounts of medical waste to ensure sanitation and personal hygiene, doing so inefficiently creates potential environmental hazards and increases operational expenses. However, hospitals lack objective criteria to select the most appropriate waste disposal firm and evaluate its performance, instead relying on their own subjective judgment and previous experiences. Therefore, this work presents an analytic hierarchy process (AHP) method to objectively select medical waste disposal firms based on the results of interviews with experts in the field, thus reducing overhead costs and enhancing medical waste management. An appropriate weight criterion based on AHP is derived to assess the effectiveness of medical waste disposal firms. The proposed AHP-based method offers a more efficient and precise means of selecting medical waste firms than subjective assessment methods do, thus reducing the potential risks for hospitals. Analysis results indicate that the medical sector selects the most appropriate infectious medical waste disposal firm based on the following rank: matching degree, contractor's qualifications, contractor's service capability, contractor's equipment and economic factors. By providing hospitals with an effective means of evaluating medical waste disposal firms, the proposed AHP method can reduce overhead costs and enable medical waste management to understand the market demand in the health sector. Moreover, performed through use of Expert Choice software, sensitivity analysis can survey the criterion weight of the degree of influence with an alternative hierarchy.

  8. p38 Mitogen-Activated Protein Kinase Mediates Lipopolysaccharide and Tumor Necrosis Factor Alpha Induction of Shiga Toxin 2 Sensitivity in Human Umbilical Vein Endothelial Cells▿ †

    PubMed Central

    Stone, Matthew K.; Kolling, Glynis L.; Lindner, Matthew H.; Obrig, Tom G.

    2008-01-01

    Escherichia coli O157:H7 Shiga toxin 2 (Stx2), one of the causative agents of hemolytic-uremic syndrome, is toxic to endothelial cells, including primary cultured human umbilical vein endothelial cells (HUVEC). This sensitivity of cells to Stx2 can be increased with either lipopolysaccharide (LPS) or tumor necrosis factor alpha (TNF-α). The goal of the present study was to identify the intracellular signaling pathway(s) by which LPS and TNF-α sensitize HUVEC to the cytotoxic effects of Stx2. To identify these pathways, specific pharmacological inhibitors and small interfering RNAs were tested with cell viability endpoints. A time course and dose response experiment for HUVEC exposure to LPS and TNF-α showed that a relatively short exposure to either agonist was sufficient to sensitize the cells to Stx2 and that both agonists stimulated intracellular signaling pathways within a short time. Cell viability assays indicated that the p38 mitogen-activated protein kinase (MAPK) inhibitors SB202190 and SB203580 and the general protein synthesis inhibitor cycloheximide inhibited both the LPS and TNF-α sensitization of HUVEC to Stx2, while all other inhibitors tested did not inhibit this sensitization. Additionally, SB202190 reduced the cellular globotriaosylceramide content under LPS- and TNF-α-induced conditions. In conclusion, our results show that LPS and TNF-α induction of Stx2 sensitivity in HUVEC is mediated through a pathway that includes p38 MAPK. These results indicate that inhibition of p38 MAPK in endothelial cells may protect a host from the deleterious effects of Stx2. PMID:18086809

  9. Selective inhibition of 11beta-hydroxysteroid dehydrogenase 1 by 18alpha-glycyrrhetinic acid but not 18beta-glycyrrhetinic acid.

    PubMed

    Classen-Houben, Dirk; Schuster, Daniela; Da Cunha, Thierry; Odermatt, Alex; Wolber, Gerhard; Jordis, Ulrich; Kueenburg, Bernhard

    2009-02-01

    Elevated cortisol concentrations have been associated with metabolic diseases such as diabetes type 2 and obesity. 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 1, catalyzing the conversion of inactive 11-ketoglucocorticoids into their active 11beta-hydroxy forms, plays an important role in the regulation of cortisol levels within specific tissues. The selective inhibition of 11beta-HSD1 is currently considered as promising therapeutic strategy for the treatment of metabolic diseases. In recent years, natural compound-derived drug design has gained considerable interest. 18beta-glycyrrhetinic acid (GA), a metabolite of the natural product glycyrrhizin, is not selective and inhibits both 11beta-HSD1 and 11beta-HSD2. Here, we compare the biological activity of 18beta-GA and its diastereomer 18alpha-GA against the two enzymes in lysates of transfected HEK-293 cells and show that 18alpha-GA selectively inhibits 11beta-HSD1 but not 11beta-HSD2. This is in contrast to 18beta-GA, which preferentially inhibits 11beta-HSD2. Using a pharmacophore model based on the crystal structure of the GA-derivative carbenoxolone in complex with human 11beta-HSD1, we provide an explanation for the differences in the activities of 18alpha-GA and 18beta-GA. This model will be used to design novel selective derivatives of GA.

  10. MWCNT-polymer composites as highly sensitive and selective room temperature gas sensors.

    PubMed

    Mangu, Raghu; Rajaputra, Suresh; Singh, Vijay P

    2011-05-27

    Multi-walled carbon nanotubes (MWCNTs)-polymer composite-based hybrid sensors were fabricated and integrated into a resistive sensor design for gas sensing applications. Thin films of MWCNTs were grown onto Si/SiO(2) substrates via xylene pyrolysis using the chemical vapor deposition technique. Polymers like PEDOT:PSS and polyaniline (PANI) mixed with various solvents like DMSO, DMF, 2-propanol and ethylene glycol were used to synthesize the composite films. These sensors exhibited excellent response and selectivity at room temperature when exposed to low concentrations (100 ppm) of analyte gases like NH(3) and NO(2). The effect of various solvents on the sensor response imparting selectivity to CNT-polymer nanocomposites was investigated extensively. Sensitivities as high as 28% were observed for an MWCNT-PEDOT:PSS composite sensor when exposed to 100 ppm of NH(3) and - 29.8% sensitivity for an MWCNT-PANI composite sensor to 100 ppm of NO(2) when DMSO was used as a solvent. Additionally, the sensors exhibited good reversibility.

  11. Synthesis of Au/Graphene Oxide Composites for Selective and Sensitive Electrochemical Detection of Ascorbic Acid

    NASA Astrophysics Data System (ADS)

    Song, Jian; Xu, Lin; Xing, Ruiqing; Li, Qingling; Zhou, Chunyang; Liu, Dali; Song, Hongwei

    2014-12-01

    In this work, we present a novel ascorbic acid (AA) sensor applied to the detection of AA in human sera and pharmaceuticals. A series of Au nanoparticles (NPs) and graphene oxide sheets (Au NP/GO) composites were successfully synthesized by reduction of gold (III) using sodium citrate. Then the Au NP/GO composites were used to construct nonenzymatic electrodes in practical AA measurement. The electrode that has the best performance presents attractive analytical features, such as a low working potential of +0.15 V, a high sensitivity of 101.86 μA mM-1 cm-2 to AA, a low detection limit of 100 nM, good reproducibility and excellent selectivity. And more,it was also employed to accurately and practically detect AA in human serum and clinical vitamin C tablet with the existence of some food additive. The enhanced AA electrochemical properties of the Au NP/GO modified electrode in our work can be attributed to the improvement of electroactive surface area of Au NPs and the synergistic effect from the combination of Au NPs and GO sheets. This work shows that the Au NP/GO/GCEs hold the prospect for sensitive and selective determination of AA in practical clinical application.

  12. Synthesis of Au/Graphene Oxide Composites for Selective and Sensitive Electrochemical Detection of Ascorbic Acid

    PubMed Central

    Song, Jian; Xu, Lin; Xing, Ruiqing; Li, Qingling; Zhou, Chunyang; Liu, Dali; Song, Hongwei

    2014-01-01

    In this work, we present a novel ascorbic acid (AA) sensor applied to the detection of AA in human sera and pharmaceuticals. A series of Au nanoparticles (NPs) and graphene oxide sheets (Au NP/GO) composites were successfully synthesized by reduction of gold (III) using sodium citrate. Then the Au NP/GO composites were used to construct nonenzymatic electrodes in practical AA measurement. The electrode that has the best performance presents attractive analytical features, such as a low working potential of +0.15 V, a high sensitivity of 101.86 μA mM−1 cm−2 to AA, a low detection limit of 100 nM, good reproducibility and excellent selectivity. And more,it was also employed to accurately and practically detect AA in human serum and clinical vitamin C tablet with the existence of some food additive. The enhanced AA electrochemical properties of the Au NP/GO modified electrode in our work can be attributed to the improvement of electroactive surface area of Au NPs and the synergistic effect from the combination of Au NPs and GO sheets. This work shows that the Au NP/GO/GCEs hold the prospect for sensitive and selective determination of AA in practical clinical application. PMID:25515430

  13. Highly selective and sensitive nanoprobes for cyanide based on gold nanoclusters with red fluorescence emission

    NASA Astrophysics Data System (ADS)

    Zhang, Guomei; Qiao, Yunyun; Xu, Ting; Zhang, Caihong; Zhang, Yan; Shi, Lihong; Shuang, Shaomin; Dong, Chuan

    2015-07-01

    We report a novel and environmentally friendly fluorescent probe for detecting the cyanide ion (CN-) using l-amino acid oxidase (LAAOx)-protected Au nanoclusters (LAAOx@AuNCs) with red emission. The fluorescence-based sensing behaviour of LAAOx@AuNCs towards anions was investigated in buffered aqueous media. Among the anions studied, CN- was found to effectively quench the fluorescence emission of AuNCs based on CN- induced Au core decomposition. Excellent sensitivity and selectivity toward the detection of CN- in aqueous solution were observed. The CN- detection limit was determined to be approximately 180 nM, which is 15 times lower than the maximum level (2700 nM) of CN- in drinking water permitted by the World Health Organization (WHO). A linear relationship between the fluorescence intensity and CN- concentration was observed in two ranges of CN- concentration, including 3.2 × 10-6 to 3.4 × 10-5 mol L-1 and 3.81 × 10-5 to 1.04 × 10-4 mol L-1. The high sensitivity and selectivity to CN- among the 17 types of anions make the AuNCs good candidates for use in fluorescent nanoprobes of CN-.

  14. Ultra-sensitive and selective Hg{sup 2+} detection based on fluorescent carbon dots

    SciTech Connect

    Liu, Ruihua; Li, Haitao; Kong, Weiqian; Liu, Juan; Liu, Yang; Tong, Cuiyan; Zhang, Xing; Kang, Zhenhui

    2013-07-15

    Graphical abstract: Fluorescent carbon dots were efficiently synthesized by one-step sodium hydroxide-assisted reflux method from PEG and demonstrated to show high selectivity toward Hg2+ ions detection. - Highlights: • FCDs were synthesized by one-step sodium hydroxide-assisted reflux method from PEG. • The FCDs emit blue photoluminescence and have upconversion fluorescent property. • The FCDs show ultra-sensitive detective ability for Hg{sup 2+} ions. - Abstract: Fluorescent carbon dots (FCDs) were efficiently synthesized by one-step sodium hydroxide-assisted reflux method from poly(ethylene glycol) (PEG). The obtained FCDs exhibit excellent water-solubility and high stability. Under the UV irradiation, the FCDs could emit bright blue photoluminescence, and also they were found to show excellent up-conversion fluorescence. It was further demonstrated that such FCDs can serve as effective fluorescent sensing platform for Hg{sup 2+} ions detection with ultra-sensitivity and selectivity. The sensing system achieved a limit of detection as low as 1 fM, which is much lower than all the previous reported sensing systems for Hg{sup 2+} ions detection. This FCDs sensing system has been successfully applied for the analysis of Hg{sup 2+} ions in water samples from river, lake, and tap water, showing good practical feasibility.

  15. Highly sensitive and selective detection of cancer cell with a label-free electrochemical cytosensor.

    PubMed

    Liu, Jiyang; Qin, Yinan; Li, Dan; Wang, Tianshu; Liu, Yaqing; Wang, Jin; Wang, Erkang

    2013-03-15

    Electrochemical methods have attracted considerable attention for developing cytosensing system since they can decrease the cost and time requirement for cell detection with simple instrumentation. Herein, a label-free electrochemical cytosensor with surface-confined ferrocene as signal indicator was developed for highly sensitive and selective detection of cancer cell. With layer-by-layer (LBL) self-assembly technique, positively charged poly(ethylene imine) functionalized with ferrocene (Fc-PEI) and negatively charged single-wall carbon nanotubes (SWNTs) were alternately assembled on 3-mercaptopropionic acid (MPA) modified gold substrate. Folic acid (FA) was covalently bonded onto SWNTs surface to specifically recognize cancer cells according to the high affinity of FA for folate receptor (FR) on cellular surface. The developed cytosensor presented high sensitivity and selectivity for the detection of human cervical carcinoma (HeLa) cell. By using fast-response differential pulse voltammetry (DPV) method, a wide detection range from 10 to 10(6) cells/mL with a detection limit as low as 10 cells/mL was reached even in the presence of a large amount of non-cancerous cells.

  16. Selective inhibition of endothelial and monocyte redox-sensitive genes by AGI-1067: a novel antioxidant and anti-inflammatory agent.

    PubMed

    Kunsch, Charles; Luchoomun, Jayraz; Grey, Janice Y; Olliff, Lynda K; Saint, Leigh B; Arrendale, Richard F; Wasserman, Martin A; Saxena, Uday; Medford, Russell M

    2004-03-01

    Atherosclerosis is a disease of oxidative stress and inflammation. AGI-1067 [butanedioic acid, mono[4-[[1-[[3,5-bis(1,1-dimethylethyl)-4-,hydroxyphenyl]thio]-1-methylethyl]thio]-2,6-bis (1,1-dimethylethyl)phenyl] ester] is a metabolically stable derivative of, yet pharmacologically distinct from, the antioxidant drug probucol. It is a member of a novel class of orally active, antioxidant, anti-inflammatory compounds termed vascular protectants and exhibits antiatherosclerotic properties in multiple animal models and in humans. To elucidate its antiatherosclerotic mechanisms, we have evaluated several cellular and molecular properties of AGI-1067 in vitro. AGI-1067 exhibited potent lipid peroxide antioxidant activity comparable with probucol yet demonstrated significantly enhanced cellular uptake over that observed with probucol. AGI-1067, but not probucol, inhibited basal levels of reactive oxygen species (ROS) in cultured primary human endothelial cells and both basal and hydrogen peroxide-induced levels of ROS in the promonocytic cell line, U937. Furthermore, AGI-1067 inhibited the inducible expression of the redox-sensitive genes, vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1, in endothelial cells as well as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, and IL-6 production in peripheral blood mononuclear cells, whereas probucol had no effect. cDNA array hybridization experiments demonstrated that AGI-1067 selectively inhibited the expression of only a subset of TNF-alpha-responsive and nuclear factor-kappaB (NF-kappaB)-inducible genes in endothelial cells. The inhibitory effect of AGI-1067 on inducible VCAM-1 gene expression occurred at the transcriptional level, yet AGI-1067 had no effect on the activation of the redox-sensitive transcription factor NF-kappaB. These studies suggest that the anti-inflammatory and antiatherosclerotic properties of AGI-1067 may be due to selective inhibition of redox-sensitive

  17. A Selective Small Molecule DNA2 Inhibitor for Sensitization of Human Cancer Cells to Chemotherapy

    PubMed Central

    Liu, Wenpeng; Zhou, Mian; Li, Zhengke; Li, Hongzhi; Polaczek, Piotr; Dai, Huifang; Wu, Qiong; Liu, Changwei; Karanja, Kenneth K.; Popuri, Vencat; Shan, Shu-ou; Schlacher, Katharina; Zheng, Li; Campbell, Judith L.; Shen, Binghui

    2016-01-01

    Cancer cells frequently up-regulate DNA replication and repair proteins such as the multifunctional DNA2 nuclease/helicase, counteracting DNA damage due to replication stress and promoting survival. Therefore, we hypothesized that blocking both DNA replication and repair by inhibiting the bifunctional DNA2 could be a potent strategy to sensitize cancer cells to stresses from radiation or chemotherapeutic agents. We show that homozygous deletion of DNA2 sensitizes cells to ionizing radiation and camptothecin (CPT). Using a virtual high throughput screen, we identify 4-hydroxy-8-nitroquinoline-3-carboxylic acid (C5) as an effective and selective inhibitor of DNA2. Mutagenesis and biochemical analysis define the C5 binding pocket at a DNA-binding motif that is shared by the nuclease and helicase activities, consistent with structural studies that suggest that DNA binding to the helicase domain is necessary for nuclease activity. C5 targets the known functions of DNA2 in vivo: C5 inhibits resection at stalled forks as well as reducing recombination. C5 is an even more potent inhibitor of restart of stalled DNA replication forks and over-resection of nascent DNA in cells defective in replication fork protection, including BRCA2 and BOD1L. C5 sensitizes cells to CPT and synergizes with PARP inhibitors. PMID:27211550

  18. ERK Signal Suppression and Sensitivity to CH5183284/Debio 1347, a Selective FGFR Inhibitor.

    PubMed

    Nakanishi, Yoshito; Mizuno, Hideaki; Sase, Hitoshi; Fujii, Toshihiko; Sakata, Kiyoaki; Akiyama, Nukinori; Aoki, Yuko; Aoki, Masahiro; Ishii, Nobuya

    2015-12-01

    Drugs that target specific gene alterations have proven beneficial in the treatment of cancer. Because cancer cells have multiple resistance mechanisms, it is important to understand the downstream pathways of the target genes and monitor the pharmacodynamic markers associated with therapeutic efficacy. We performed a transcriptome analysis to characterize the response of various cancer cell lines to a selective fibroblast growth factor receptor (FGFR) inhibitor (CH5183284/Debio 1347), a mitogen-activated protein kinase kinase (MEK) inhibitor, or a phosphoinositide 3-kinase (PI3K) inhibitor. FGFR and MEK inhibition produced similar expression patterns, and the extracellular signal-regulated kinase (ERK) gene signature was altered in several FGFR inhibitor-sensitive cell lines. Consistent with these findings, CH5183284/Debio 1347 suppressed phospho-ERK in every tested FGFR inhibitor-sensitive cell line. Because the mitogen-activated protein kinase (MAPK) pathway functions downstream of FGFR, we searched for a pharmacodynamic marker of FGFR inhibitor efficacy in a collection of cell lines with the ERK signature and identified dual-specificity phosphatase 6 (DUSP6) as a candidate marker. Although a MEK inhibitor suppressed the MAPK pathway, most FGFR inhibitor-sensitive cell lines are insensitive to MEK inhibitors and we found potent feedback activation of several pathways via FGFR. We therefore suggest that FGFR inhibitors exert their effect by suppressing ERK signaling without feedback activation. In addition, DUSP6 may be a pharmacodynamic marker of FGFR inhibitor efficacy in FGFR-addicted cancers.

  19. Basis for sensitive and selective time-delayed luminescence detection of hydroxyl radical by lanthanide complexes.

    PubMed

    Peterson, Katie L; Margherio, Maximilian J; Doan, Phi; Wilke, Kyle T; Pierre, Valérie C

    2013-08-19

    Molecular probes for the detection of hydroxyl radical (HO•) by time-delayed luminescence spectroscopy directly in water at neutral pH with high sensitivity and selectivity are presented. The bimolecular probes consist of a lanthanide complex with open coordination sites and a reactive pre-antenna composed of an aromatic acid or amide; the latter binds to and sensitizes terbium emission upon hydroxylation by HO•. These probes exhibit long luminescence lifetimes compatible with time-delayed measurements that remove interfering background fluorescence from the sample. Six different reactive pre-antenna (benzoate, benzamide, isophthalate, isophthalamide, trimesate, and trimesamide) and two different terbium complexes [Tb-(1,4,7,10-tetraazacyclododecane-1,4,7-tris(acetic acid)) (Tb-DO3A) and Tb-(1,4,7,10-tetraazacyclododecane-1,7-bis(acetic acid)) (Tb-DO2A)] were evaluated. Of these the trimesamide/Tb-DO3A system enables the most sensitive detection of HO• with an about 1000-fold increase in metal-centered time-delayed emission upon hydroxylation of the pre-antenna to 2-hydroxytrimesamide. Excellent selectivity for both the trimesamide/Tb-DO3A and trimesate/Tb-DO3A systems over other reactive oxygen and nitrogen species are observed. Notably, the increase in metal-centered luminescence intensity is not associated with a decrease in the hydration number (q) of Tb-DO3A, suggesting that the antenna is interacting with the lanthanide via a second sphere coordination environment or that coordination by the antenna occurs by displacement of one or more of the carboxylate arms of DO3A. Formation of a weak ternary complex Tb-DO3A•hydroxytrimesamide was confirmed by temperature-dependent titration and a decrease in K(app) with increasing temperature.

  20. Role of cytochrome C in apoptosis: increased sensitivity to tumor necrosis factor alpha is associated with respiratory defects but not with lack of cytochrome C release.

    PubMed

    Vempati, Uma D; Diaz, Francisca; Barrientos, Antoni; Narisawa, Sonoko; Mian, Abdul M; Millán, José Luis; Boise, Lawrence H; Moraes, Carlos T

    2007-03-01

    Although the role of cytochrome c in apoptosis is well established, details of its participation in signaling pathways in vivo are not completely understood. The knockout for the somatic isoform of cytochrome c caused embryonic lethality in mice, but derived embryonic fibroblasts were shown to be resistant to apoptosis induced by agents known to trigger the intrinsic apoptotic pathway. In contrast, these cells were reported to be hypersensitive to tumor necrosis factor alpha (TNF-alpha)-induced apoptosis, which signals through the extrinsic pathway. Surprisingly, we found that this cell line (CRL 2613) respired at close to normal levels because of an aberrant activation of a testis isoform of cytochrome c, which, albeit expressed at low levels, was able to replace the somatic isoform for respiration and apoptosis. To produce a bona fide cytochrome c knockout, we developed a mouse knockout for both the testis and somatic isoforms of cytochrome c. The mouse was made viable by the introduction of a ubiquitously expressed cytochrome c transgene flanked by loxP sites. Lung fibroblasts in which the transgene was deleted showed no cytochrome c expression, no respiration, and resistance to agents that activate the intrinsic and to a lesser but significant extent also the extrinsic pathways. Comparison of these cells with lines with a defective oxidative phosphorylation system showed that cells with defective respiration have increased sensitivity to TNF-alpha-induced apoptosis, but this process was still amplified by cytochrome c. These studies underscore the importance of oxidative phosphorylation and apoptosome function to both the intrinsic and extrinsic apoptotic pathways.

  1. Enantioselective alpha-arylation of aldehydes via organo-SOMO catalysis. An ortho-selective arylation reaction based on an open-shell pathway.

    PubMed

    Conrad, Jay C; Kong, Jongrock; Laforteza, Brian N; MacMillan, David W C

    2009-08-26

    The intramolecular alpha-arylation of aldehydes has been accomplished using singly occupied molecular orbital (SOMO) catalysis. Selective oxidation of chiral enamines (formed by the condensation of an aldehyde and a secondary amine catalyst) leads to the formation of a 3pi-electron radical species. These chiral SOMO-activated radical cations undergo enantioselective reaction with an array of pendent electron-rich aromatics and heterocycles thus efficiently providing cyclic alpha-aryl aldehyde products (10 examples: > or = 70% yield and > or = 90% ee). In accordance with our radical mechanism, when there is a choice between arylation at the ortho or para position of anisole substrates, we find that arylation proceeds selectively at the ortho position.

  2. In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against Clostridium difficile Toxin B and Sensitive Detection in Human Fecal Matter

    PubMed Central

    Maher, Eamonn; Williams, Ryan M.; Sooter, Letha J.

    2015-01-01

    Toxin B is one of the major virulence factors of Clostridium difficile, a bacterium that is responsible for a significant number of diarrhea cases in acute care settings. Due to the prevalence of C. difficile induced diarrhea, rapid and correct diagnosis is crucial in the disease management. In this study, we have employed a stringent in vitro selection method to identify single-stranded DNA molecular recognition elements (MRE) specific for toxin B. At the end of the 12-round selection, one MRE with high affinity (Kd = 47.3 nM) for toxin B was identified. The selected MRE demonstrated low cross binding activities on negative targets: bovine serum albumin, Staphylococcus aureus alpha toxin, Pseudomonas aeruginosa exotoxin A, and cholera toxin of Vibrio cholera. A modified sandwich ELISA assay was developed utilizing the selected ssDNA MRE as the antigen capturing element and achieved a sensitive detection of 50 nM of toxin B in human fecal preparations. PMID:25734010

  3. Role of the nitric oxide synthase pathway in inhibition of growth of interferon-sensitive and interferon-resistant Rickettsia prowazekii strains in L929 cells treated with tumor necrosis factor alpha and gamma interferon.

    PubMed Central

    Turco, J; Winkler, H H

    1993-01-01

    The ability of tumor necrosis factor alpha (TNF-alpha) alone and in combination with gamma interferon (IFN-gamma) to inhibit the growth of interferon-sensitive and -resistant Rickettsia prowazekii strains in mouse L929 cells was examined, and the possible role of the nitric oxide synthase pathway in the suppression of rickettsial growth induced by TNF-alpha, IFN-gamma, or both cytokines was evaluated. TNF-alpha inhibited the growth of strains Madrid E (IFN-gamma sensitive and alpha/beta interferon [IFN-alpha/beta] sensitive) and Breinl (IFN-gamma sensitive and IFN-alpha/beta resistant), but not that of strain 83-2P (IFN-gamma resistant and IFN-alpha/beta resistant), in L929 cells. Inhibition of the growth of the Madrid E strain in L929 cells treated with TNF-alpha and IFN-gamma in combination was greater than that observed with either TNF-alpha or IFN-gamma alone. Similarly, inhibition of the growth of the Breinl strain in L929 cells treated with both cytokines was greater than that observed with TNF-alpha alone; however, it did not differ significantly from the inhibition observed with IFN-gamma alone. Although strain 83-2P was resistant to TNF-alpha or IFN-gamma alone, its growth was inhibited in L929 cells treated with TNF-alpha and IFN-gamma in combination. Nitrite production was measured in mock-infected and infected L929 cell cultures, and the nitric oxide synthase inhibitors NG-methyl-L-arginine (NGMA) and aminoguanidine were used to evaluate the role of the nitric oxide synthase pathway in cytokine-induced inhibition of rickettsial growth. Nitrite production was induced in mock-infected or R. prowazekii-infected L929 cell cultures treated with IFN-gamma plus TNF-alpha, but not in mock-infected cultures that were untreated or treated with IFN-gamma or TNF-alpha alone. Nitrite production was also not induced in untreated, R. prowazekii-infected cultures; however, in some instances, it was induced in infected cultures treated with IFN-gamma or TNF-alpha alone

  4. Chrysin sensitizes tumor necrosis factor-alpha-induced apoptosis in human tumor cells via suppression of nuclear factor-kappaB.

    PubMed

    Li, Xin; Huang, Qing; Ong, Choon-Nam; Yang, Xing-Fen; Shen, Han-Ming

    2010-07-01

    Chrysin (5,7-dihydroxyflavone) is a natural flavonoid commonly found in many plants. The anti-cancer property of chrysin has been demonstrated although the molecular mechanisms remain to be further elucidated. In the present study, we found that, pretreatment with chrysin greatly sensitized various human cancer cells to tumor necrosis factor-alpha (TNFalpha)-induced apoptosis. In the search of the molecular mechanisms responsible for the sensitization effect of chrysin, we discovered that such sensitization is closely associated with the inhibitory effect of chrysin on TNFalpha-mediated nuclear transcription factor-kappaB (NF-kappaB) activation. Pretreatment with chrysin inhibited TNFalpha-induced degradation of Inhibitor of kappaB (IkappaB) protein and subsequent nuclear translocation of p65. As a result, chrysin suppressed the expression of NF-kappaB-targeted anti-apoptotic gene, c-FLIP-L. The role of c-FLIP-L was further confirmed by its ectopic expression, which significantly protected cell death induced by combined treatment with chrysin and TNFalpha. Data from this study thus reveal a novel function of chrysin and enhance the value of chrysin as an anti-cancer agent.

  5. Tellurium-nanowire-coated glassy carbon electrodes for selective and sensitive detection of dopamine.

    PubMed

    Tsai, Hsiang-Yu; Lin, Zong-Hong; Chang, Huan-Tsung

    2012-05-15

    Tellurium-nanowire-coated glassy carbon electrodes (TNGCEs) have been fabricated and employed for selective and sensitive detection of dopamine (DA). TNGCEs were prepared by direct deposition of tellurium nanowires, 600 ± 150 nm in length and 16 ± 3 nm in diameter, onto glassy carbon electrodes, which were further coated with Nafion to improve their selectivity and stability. Compared to the GCE, the TNGCE is more electroactive (by approximately 1.9-fold) for DA, and its selectivity toward DA over ascorbic acid (AA) and uric acid (UA) is also greater. By applying differential pulse voltammetry, at a signal-to-noise ratio of 3, the TNGCE provides a limit of detection of 1 nM for DA in the presence of 0.5mM AA and UA. Linearity (R(2)=0.9955) of the oxidation current at 0.19 V against the concentration of DA is found over the range 5 nM-1 μM. TNGCEs have been applied to determine the concentration of dopamine to be 0.59 ± 0.07 μM in PC12 cells.

  6. Impact of gsp oncogene on the expression of genes coding for Gsalpha, Pit-1, Gi2alpha, and somatostatin receptor 2 in human somatotroph adenomas: involvement in octreotide sensitivity.

    PubMed

    Barlier, A; Pellegrini-Bouiller, I; Gunz, G; Zamora, A J; Jaquet, P; Enjalbert, A

    1999-08-01

    The impact of the gsp oncogene on the expression of genes engaged in the somatotroph cell phenotype remains poorly understood in human somatotroph adenomas. As the gsp oncogene is associated with an increased octreotide (somatostatin agonist) sensitivity, a group of 8 somatotroph adenomas bearing the gsp mutation (gsp+) and another group of 16 adenomas without the mutation (gsp-) were analyzed, all of them presenting variable octreotide sensitivities. The expressions of genes encoding for G(s)alpha, Pit-1, G(i2)alpha, and SSTR2, involved in the regulation of secretory activity in somatotroph cells, were assessed by Northern blot. A decreased expression of the G(s)alpha gene was found in gsp + tumors, suggesting the existence of a negative feedback of the oncogenic protein upon its own messenger ribonucleic acid (mRNA). In contrast, G(i2)alpha, Pit-1, and GH messengers were not significantly different in the groups. A positive correlation between the in vitro and in vivo GH octreotide-induced secretory inhibition and the expression of SSTR2 mRNA was found. However, the expression of the gene for SSTR2 appeared not to be different between gsp + and gsp-, even when the octreotide sensitivity was significantly higher in the adenomas carrying the mutation. Interestingly, the SSTR2 gene expression was significantly correlated to those of G(i2)alpha and Pit-1. In the same way, the G(s)alpha mRNA expression was positively correlated with those of Gi2alpha and Pit-1. Such correlations strongly suggest a concerted dysregulation of the expression of these genes in both categories of adenomas. The loss of the octreotide sensitivity represents one aspect of the dysregulation process that partially results from the decreased SSTR2 expression. However, the improvement of the sensitivity associated with the presence of the gsp oncogene seems to proceed in a way different from SSTR2 expression.

  7. A Gene Selection Method for Microarray Data Based on Binary PSO Encoding Gene-to-Class Sensitivity Information.

    PubMed

    Han, Fei; Yang, Chun; Wu, Ya-Qi; Zhu, Jian-Sheng; Ling, Qing-Hua; Song, Yu-Qing; Huang, De-Shuang

    2017-01-01

    Traditional gene selection methods for microarray data mainly considered the features' relevance by evaluating their utility for achieving accurate predication or exploiting data variance and distribution, and the selected genes were usually poorly explicable. To improve the interpretability of the selected genes as well as prediction accuracy, an improved gene selection method based on binary particle swarm optimization (BPSO) and prior information is proposed in this paper. In the proposed method, BPSO encoding gene-to-class sensitivity (GCS) information is used to perform gene selection. The gene-to-class sensitivity information, extracted from the samples by extreme learning machine (ELM), is encoded into the selection process in four aspects: initializing particles, updating the particles, modifying maximum velocity, and adopting mutation operation adaptively. Constrained by the gene-to-class sensitivity information, the new method can select functional gene subsets which are significantly sensitive to the samples' classes. With the few discriminative genes selected by the proposed method, ELM, K-nearest neighbor and support vector machine classifiers achieve much high prediction accuracy on five public microarray data, which in turn verifies the efficiency and effectiveness of the proposed gene selection method.

  8. FIRST SPECTROSCOPIC MEASUREMENTS OF [O III] EMISSION FROM Ly{alpha} SELECTED FIELD GALAXIES AT z {approx} 3.1

    SciTech Connect

    McLinden, Emily M.; Rhoads, James E.; Malhotra, Sangeeta; Hibon, Pascale; Richardson, Mark L. A.; Finkelstein, Steven L.; Cresci, Giovanni; Quirrenbach, Andreas; Pasquali, Anna; Bian Fuyan; Fan Xiaohui; Woodward, Charles E.

    2011-04-01

    We present the first spectroscopic measurements of the [O III] 5007 A line in two z {approx} 3.1 Ly{alpha} emitting galaxies (LAEs) using the new near-infrared instrument LUCIFER1 on the 8.4 m Large Binocular Telescope. We also describe the optical imaging and spectroscopic observations used to identify these LAEs. Using the [O III] line we have measured accurate systemic redshifts for these two galaxies, and discovered a velocity offset between the [O III] and Ly{alpha} lines in both, with the Ly{alpha} line peaking 342 and 125 km s{sup -1} redward of the systemic velocity. These velocity offsets imply that there are powerful outflows in high-redshift LAEs. They also ease the transmission of Ly{alpha} photons through the interstellar medium and intergalactic medium around the galaxies. By measuring these offsets directly, we can refine both Ly{alpha}-based tests for reionization, and Ly{alpha} luminosity function measurements where the Ly{alpha} forest affects the blue wing of the line. Our work also provides the first direct constraints on the strength of the [O III] line in high-redshift LAEs. We find [O III] fluxes of 7 and 36 x10{sup -17} erg s{sup -1} cm{sup -2} in two z {approx} 3.1 LAEs. These lines are strong enough to dominate broadband flux measurements that include the line (in this case, K{sub s} -band photometry). Spectral energy distribution fits that do not account for the lines would therefore overestimate the 4000 A (and/or Balmer) break strength in such galaxies, and hence also the ages and stellar masses of such high-z galaxies.

  9. Association between expression of the H histo-blood group antigen, alpha1,2fucosyltransferases polymorphism of wild rabbits, and sensitivity to rabbit hemorrhagic disease virus.

    PubMed

    Guillon, Patrice; Ruvoën-Clouet, Nathalie; Le Moullac-Vaidye, Béatrice; Marchandeau, Stéphane; Le Pendu, Jacques

    2009-01-01

    RHDV (rabbit hemorrhagic disease virus) is a highly virulent calicivirus that has become a major cause of mortality in wild rabbit populations (Oryctolagus cuniculus). It binds to the histo-blood group antigen (HBGA) H type 2 which requires an alpha1,2fucosyltransferase for its synthesis. In rabbit, three alpha1,2fucosyltransferases genes are known, Fut1, Fut2, and Sec1. Nonfunctional alleles at any of these loci could potentially confer resistance to RHDV, similar to human FUT2 alleles that determine the nonsecretor phenotype and resistance to infection by various NoV strains. In this study, we looked for the presence of H type 2 on buccal epithelial cells of wild rabbits from two geographic areas under RHDV pressure and from one RHDV-free area. Some animals with diminished H type 2 expression were found in the three populations (nonsecretor-like phenotype). Their frequency markedly increased according to the RHDV impact, suggesting that outbreaks selected survivors with low expression of the virus ligand. Polymorphisms of the Fut1, Fut2, and Sec1 coding regions were determined among animals that either died or survived outbreaks. The Fut2 and Sec1 genes presented a high polymorphism and the frequency of one Sec1 allele was significantly elevated, over 6-fold, among survivors. Sec1 enzyme variants showed either moderate, low, or undetectable catalytic activity, whereas all variant Fut2 enzymes showed strong catalytic activity. This functional analysis of the enzymes encoded by each Fut2 and Sec1 allele suggests that the association between one Sec1 allele and survival might be explained by a deficit of alpha1,2fucosyltransferase expression rather than by impaired catalytic activity.

  10. TNF-alpha blockade by a dimeric TNF type I receptor molecule selectively inhibits adaptive immune responses.

    PubMed

    Colagiovanni, D B; Suniga, M A; Frazier, J L; Edwards, C K; Fleshner, M; McCay, J A; White, K L; Shopp, G M

    2000-11-01

    Tumor necrosis factor-alpha (TNF-alpha) is a mediator of severe inflammatory processes, including rheumatoid arthritis. Suppression of TNF with a soluble type I or type II receptor molecule (TNF-RI or TNF-RII) has the potential to decrease cytokine levels and modulate inflammatory diseases in humans. However, it has recently been reported that treatment of mice with a TNF-RI:Fc immunoadhesin protein augmented Gram positive infections and subsequent mortality. To determine if TNF-alpha blockade with soluble TNF-alpha receptors might alter immune system function, assays were assessed in rodents treated with a dimeric form of the p55 TNF-RI, Tumor Necrosis Factor-binding protein (TNFbp). Administration of TNFbp resulted in suppression of primary and secondary IgG antibody responses and cell-mediated immune function. No treatment-related differences were detected in immune-enhancing assays or non-specific immune function parameters. Bacterial host resistance assays with Listeria monocytogenes, Staphylococcus aureus or Escherichia coli showed an increase in tissue colony counts only with L. monocytogenes challenged animals following TNFbp administration. These results suggest that TNFbp has the capacity to inhibit adaptive immune function in experimental animal models. Studies suggest that while reducing TNF-alpha is important in controlling cytokine-dependent disease states, maintenance of a threshold level may be critical for normal immune function.

  11. Zinc Selectively Blocks Neurosteroid-Sensitive Extrasynaptic δGABAA Receptors in the Hippocampus

    PubMed Central

    Carver, Chase Matthew; Chuang, Shu-Hui

    2016-01-01

    hippocampus circuits. Zn2+ inhibits synaptic GABAA receptors, but its interaction is less well appreciated at the extrasynaptic receptors, which respond sensitively to endogenous neurosteroids. Here, we describe selective functional blockade by Zn2+ of neurosteroid-sensitive, extrasynaptic GABAA receptors in the mouse hippocampus dentate gyrus, a key region associated with epilepsy and memory disorders. By demonstrating that extracellular Zn2+ prevents neurosteroid augmentation of tonic current and protection against limbic seizures, our findings provide novel implications of this potential antagonistic interaction in a variety of neurological conditions. PMID:27488628

  12. Sensitive and selective SERS probe for trivalent chromium detection using citrate attached gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Ye, Yingjie; Liu, Honglin; Yang, Liangbao; Liu, Jinhuai

    2012-09-01

    In this article, we have demonstrated a sensitive and selective surface enhanced Raman spectroscopy (SERS) probe, based on citrate-capped gold nanoparticles (AuNPs), for trivalent chromium (Cr3+) detection. After introducing Tween 20 to a solution of citrate-capped AuNPs, the as-prepared Tween 20/citrate-AuNP probe could recognize Cr3+ at a 50 × 10-9 M level in an aqueous medium at a pH of 6.0. Tween 20 can stabilize the citrate-capped AuNPs against conditions of high ionic strength. Due to the chelation between Cr3+ and citrate ions, AuNPs undergo aggregation. As a result, it formed several hot spots and provided a significant enhancement of the Raman signal intensity through electromagnetic (EM) field enhancements. A detailed mechanism for tremendous SERS intensity change had been discussed. The selectivity of this system toward Cr3+ was 400-fold, remarkably greater than other metal ions.In this article, we have demonstrated a sensitive and selective surface enhanced Raman spectroscopy (SERS) probe, based on citrate-capped gold nanoparticles (AuNPs), for trivalent chromium (Cr3+) detection. After introducing Tween 20 to a solution of citrate-capped AuNPs, the as-prepared Tween 20/citrate-AuNP probe could recognize Cr3+ at a 50 × 10-9 M level in an aqueous medium at a pH of 6.0. Tween 20 can stabilize the citrate-capped AuNPs against conditions of high ionic strength. Due to the chelation between Cr3+ and citrate ions, AuNPs undergo aggregation. As a result, it formed several hot spots and provided a significant enhancement of the Raman signal intensity through electromagnetic (EM) field enhancements. A detailed mechanism for tremendous SERS intensity change had been discussed. The selectivity of this system toward Cr3+ was 400-fold, remarkably greater than other metal ions. Electronic supplementary information (ESI) available: Fig. S1-S5. See DOI: 10.1039/c2nr31985c

  13. A new hydroxynaphthyl benzothiazole derived fluorescent probe for highly selective and sensitive Cu2 + detection

    NASA Astrophysics Data System (ADS)

    Tang, Lijun; He, Ping; Zhong, Keli; Hou, Shuhua; Bian, Yanjiang

    2016-12-01

    A new reactive probe, 1-(benzo[d]thiazol-2-yl)naphthalen-2-yl-picolinate (BTNP), was designed and synthesized. BTNP acts as a highly selective probe to Cu2 + in DMSO/H2O (7/3, v/v, Tris-HCl 10 mM, pH = 7.4) solution based on Cu2 + catalyzed hydrolysis of the picolinate ester moiety in BTNP, which leads to the formation of an ESIPT active product with dual wavelength emission enhancement. The probe also possesses the advantages of simple synthesis, rapid response and high sensitivity. The pseudo-first-order reaction rate constant was calculated to be 0.205 min- 1. Moreover, application of BTNP to Cu2 + detection in living cells and real water samples was also explored.

  14. Surface-selective laser sintering of thermolabile polymer particles using water as heating sensitizer

    SciTech Connect

    Antonov, E N; Krotova, L I; Minaev, N V; Minaeva, S A; Mironov, A V; Popov, V K; Bagratashvili, V N

    2015-11-30

    We report the implementation of a novel scheme for surface-selective laser sintering (SSLS) of polymer particles, based on using water as a sensitizer of laser heating and sintering of particles as well as laser radiation at a wavelength of 1.94 μm, corresponding to the strong absorption band of water. A method of sintering powders of poly(lactide-co-glycolide), a hydrophobic bioresorbable polymer, after modifying its surface with an aqueous solution of hyaluronic acid is developed. The sintering thresholds for wetted polymer are by 3 – 4 times lower than those for sintering in air. The presence of water restricts the temperature of the heated polymer, preventing its thermal destruction. Polymer matrices with a developed porous structure are obtained. The proposed SSLS method can be applied to produce bioresorbable polymer matrices for tissue engineering. (interaction of laser radiation with matter. laser plasma)

  15. Highly functionalized tetrahydropyridines are cytotoxic and selective inhibitors of human puromycin sensitive aminopeptidase.

    PubMed

    Aeluri, Raghunath; Ganji, Roopa Jones; Marapaka, Anil Kumar; Pillalamarri, Vijaykumar; Alla, Manjula; Addlagatta, Anthony

    2015-12-01

    Efficient one-pot five-component synthetic protocols for highly functionalized tetrahydropyridines (THPs) and their biological evaluation have been illustrated. Synthesis of novel functionalized tetrahydropyridines containing differential substitutions at 2,6-positions has been achieved via a modified MCR. Cytotoxic studies of 23 synthesized compounds have been carried out against three different cell lines, namely A-549, HeLa and HepG2, wherein some compounds have displayed appreciable cytotoxicity. Further, investigation of enzyme inhibition by the synthesized THPs has been carried out against four members of M1 family aminopeptidases. Several compounds have selectively inhibited only one member of this enzyme family i.e., human puromycin sensitive aminopeptidase (hPSA). Among the compounds; 4b, 9b, 9e and 10a demonstrated best inhibition against hPSA.

  16. Selective and sensitive determination of dopamine by composites of polypyrrole and graphene modified electrodes.

    PubMed

    Si, Peng; Chen, Hailan; Kannan, Palanisamy; Kim, Dong-Hwan

    2011-12-21

    A novel method is developed to fabricate the polypyrrole (PPy) and graphene thin films on electrodes by electrochemical polymerization of pyrrole with graphene oxide (GO) as a dopant, followed by electrochemical reduction of GO in the composite film. The composite of PPy and electrochemically reduced graphene oxide (eRGO)-modified electrode is highly sensitive and selective toward the detection of dopamine (DA) in the presence of high concentrations of ascorbic acid (AA) and uric acid (UA). The sensing performance of the PPy/eRGO-modified electrode is investigated by differential pulse voltammetry (DPV), revealing a linear range of 0.1-150 μM with a detection limit of 23 nM (S/N = 3). The practical application of the PPy/eRGO-modified electrode is successfully demonstrated for DA determination in human blood serum.

  17. Surface-selective laser sintering of thermolabile polymer particles using water as heating sensitizer

    NASA Astrophysics Data System (ADS)

    Antonov, E. N.; Krotova, L. I.; Minaev, N. V.; Minaeva, S. A.; Mironov, A. V.; Popov, V. K.; Bagratashvili, V. N.

    2015-11-01

    We report the implementation of a novel scheme for surface-selective laser sintering (SSLS) of polymer particles, based on using water as a sensitizer of laser heating and sintering of particles as well as laser radiation at a wavelength of 1.94 μm, corresponding to the strong absorption band of water. A method of sintering powders of poly(lactide-co-glycolide), a hydrophobic bioresorbable polymer, after modifying its surface with an aqueous solution of hyaluronic acid is developed. The sintering thresholds for wetted polymer are by 3 - 4 times lower than those for sintering in air. The presence of water restricts the temperature of the heated polymer, preventing its thermal destruction. Polymer matrices with a developed porous structure are obtained. The proposed SSLS method can be applied to produce bioresorbable polymer matrices for tissue engineering.

  18. Conducting Polymer-Based Nanohybrid Transducers: A Potential Route to High Sensitivity and Selectivity Sensors

    PubMed Central

    Park, Seon Joo; Kwon, Oh Seok; Lee, Ji Eun; Jang, Jyongsik; Yoon, Hyeonseok

    2014-01-01

    The development of novel sensing materials provides good opportunities to realize previously unachievable sensor performance. In this review, conducting polymer-based nanohybrids are highlighted as innovative transducers for high-performance chemical and biological sensing devices. Synthetic strategies of the nanohybrids are categorized into four groups: (1) impregnation, followed by reduction; (2) concurrent redox reactions; (3) electrochemical deposition; (4) seeding approach. Nanocale hybridization of conducting polymers with inorganic components can lead to improved sorption, catalytic reaction and/or transport behavior of the material systems. The nanohybrids have thus been used to detect nerve agents, toxic gases, volatile organic compounds, glucose, dopamine, and DNA. Given further advances in nanohybrids synthesis, it is expected that sensor technology will also evolve, especially in terms of sensitivity and selectivity. PMID:24561406

  19. Highly selective, sensitive and fast-responsive fluorescent sensor for Hg2 +

    NASA Astrophysics Data System (ADS)

    Niu, Qingfen; Wu, Xingxing; Li, Tianduo; Cui, Yuezhi; Zhang, Shanshan; Li, Xiaoyan

    2016-06-01

    A phenylamine-oligothiophene-based fluorescent sensor 2TBEA was reported. This sensor exhibited highly selective, sensitive and rapid detection of Hg2 + ion in THF/H2O (7/3, v/v) solution through fluorescence quenching. The detection was unaffected by the coexistence of other competitive metal cations including Na+, K+, Ag+, Ca2 +, Fe3 +, Al3 +, Co2 +, Cu2 +, Ni2 +, Zn2 +, Pb2 +, Cd2 +, Fe2 + and Cr3 +. A1:1 binding ratio for 2TBEA - Hg2 + was demonstrated by Job's plot and mole-ratio curves. The coordination process was chemically reversible with EDTA. The detection limit was evaluated to be as low as 6.164 × 10- 8 M.

  20. A new diketopyrrolopyrrole-based probe for sensitive and selective detection of sulfite in aqueous solution

    NASA Astrophysics Data System (ADS)

    Yang, Xiaofeng; Cui, Yu; Li, Yexin; Zheng, Luyi; Xie, Lijun; Ning, Rui; Liu, Zheng; Lu, Junling; Zhang, Gege; Liu, Chunxiang; Zhang, Guangyou

    2015-02-01

    A new probe was synthesized by incorporating an α,β -unsaturated ketone to a diketopyrrolopyrrole fluorophore. The probe had exhibited a selective and sensitive response to the sulfite against other thirteen anions and biothiols (Cys, Hcy and GSH), through the nucleophilic addition of sulfite to the alkene of probe with the detection limit of 0.1 μM in HEPES (10 mM, pH 7.4) THF/H2O (1:1, v/v). Meanwhile, it could be easily observed that the probe for sulfite changed from pink to colorless by the naked eye, and from pink to blue under UV lamp after the sulfite was added for 20 min. The NMR and Mass spectral analysis demonstrated the expected addition of sulfite to the Cdbnd C bonds.

  1. Sensitive and Selective Detection of HIV-1 RRE RNA Using Vertical Silicon Nanowire Electrode Array

    NASA Astrophysics Data System (ADS)

    Lee, Jaehyung; Hong, Min-Ho; Han, Sanghun; Na, Jukwan; Kim, Ilsoo; Kwon, Yong-Joon; Lim, Yong-beom; Choi, Heon-Jin

    2016-07-01

    In this study, HIV-1 Rev response element (RRE) RNA was detected via an Au-coated vertical silicon nanowire electrode array (VSNEA). The VSNEA was fabricated by combining bottom-up and top-down approaches and then immobilized by artificial peptides for the recognition of HIV-1 RRE. Differential pulse voltammetry (DPV) analysis was used to measure the electrochemical response of the peptide-immobilized VSNEA to the concentration and types of HIV-1 RRE RNA. DPV peaks showed linearity to the concentration of RNA with a detection limit down to 1.513 fM. It also showed the clear different peaks to the mutated HIV-1 RRE RNA. The high sensitivity and selectivity of VSNEA for the detection of HIV-1 RRE RNA may be attributed to the high surface-to-volume ratio and total overlap diffusion mode of ions of the one-dimensional nanowire electrodes.

  2. Highly sensitive and selective electrochemical dopamine sensing properties of multilayer graphene nanobelts

    NASA Astrophysics Data System (ADS)

    Karthick Kannan, Padmanathan; Moshkalev, Stanislav A.; Sekhar Rout, Chandra

    2016-02-01

    In the present study, we report the electrochemical sensing property of multi-layer graphene nanobelts (GNBs) towards dopamine (DA). GNBs are synthesized from natural graphite and characterized by using techniques like field-emission scanning electron microscopy, atomic force microscopy and Raman spectroscopy. An electrochemical sensor based on GNBs is developed for the detection of DA. From the cyclic voltammetry and amperometry studies, it is found that GNBs possess excellent electrocatalytic activity towards DA molecules. The developed DA sensor showed a sensitivity value of 0.95 μA μM-1 cm-2 with a linear range of 2 μM to 0.2 mM. The interference data exhibited that GNB is highly selective to DA even in the presence of common interfering species like ascorbic acid, uric acid, glucose and lactic acid.

  3. Analysis of T cell receptor repertoire of muscle-infiltrating T lymphocytes in polymyositis. Restricted V alpha/beta rearrangements may indicate antigen-driven selection.

    PubMed Central

    Mantegazza, R; Andreetta, F; Bernasconi, P; Baggi, F; Oksenberg, J R; Simoncini, O; Mora, M; Cornelio, F; Steinman, L

    1993-01-01

    Polymyositis is an inflammatory myopathy characterized by mononuclear cell infiltration of muscle tissue. Myocytotoxic T lymphocytes have been recognized in the infiltrates, but the muscle antigen, target of the immune attack, has not been identified. Molecular characterization of the variable regions of T cell receptors (TCRs) on the infiltrating lymphocytes can be expected to provide insights into the pathogenic process. The V alpha/beta TCR repertoire was investigated by RNA-PCR in muscle biopsies from 15 polymyositis patients and 16 controls (6 Duchenne muscular dystrophy and 10 with no inflammatory or dystrophic myopathy). A variety of rearranged variable TCR genes was found in polymyositis, V alpha 1, V alpha 5, V beta 1, and V beta 15 being the most common (present in 60-100% of patients). In Duchenne muscular dystrophy patients TCR V alpha or beta rearrangements were found although no restriction was observed; no rearrangements were found in muscles from the other controls. Sequence analysis revealed the presence of the J beta 2.1 region in 90% of the V beta 15 clones studied, no random N additions in the diversity region, and a common motif within the CDR3 region. These results suggest that selection of muscle-infiltrating T lymphocytes is antigen driven in polymyositis. Images PMID:8514895

  4. Selection of Parasites with Diminished Drug Sensitivity by Amodiaquine-Containing Antimalarial Regimens in Uganda

    PubMed Central

    Nawaz, Fatima; Nsobya, Samuel L.; Kiggundu, Moses; Joloba, Moses; Rosenthal, Philip J.

    2009-01-01

    Background Amodiaquine (AQ) is paired with artesunate (AS) or sulfadoxine-pyrimethamine (SP) in recommended antimalarial regimens. It is unclear how readily AQ resistance will be selected with combination chemotherapy. Methods We collected 61 Plasmodium falciparum samples from a cohort of Ugandan children randomized to treatment with AQ/SP, AS/AQ, or artemether-lumefantrine (AL) for uncomplicated malaria. In vitro sensitivity to monodesethylamodiaquine (MDAQ) was measured with a histidine rich protein-2-based ELISA, and potential resistance-mediating polymorphisms pfmdr-1were evaluated. Results Parasites from subjects previously treated with AQ/SP or AS/AQ within 12 weeks were less sensitive to MDAQ (n=18; mean IC50 62.9 nM; range 12.7–158.3 nM) than parasites from those not treated within 12 weeks (n=43; mean IC50 37.5 nM; range 6.3–184.7 nM; p=0.0085) or only those in the treatment arm that did not contain AQ (n=20; mean IC50 28.8 nM; range 6.3–121.8 nM; p=0.0042). The proportion of strains with polymorphisms expected to mediate diminished response to AQ (pfmdr-1 86Y and 1246Y) increased after prior AQ therapy, although differences were not significant. Conclusions Prior therapy selected for diminished response to MDAQ, suggesting that AQ-containing regimens may rapidly lose efficacy in Africa. The mechanism of diminished MDAQ response is not fully explained by known mutations in pfmdr-1. PMID:19905933

  5. Multi-ion and pH sensitivity of AgGeSe ion selective electrodes

    NASA Astrophysics Data System (ADS)

    Conde Garrido, J. M.; Silveyra, J. M.; Ureña, M. A.

    2016-02-01

    Many chalcogenide glasses have been found to combine benefits such as good chemical durability, selectivity, and reproducibility for applications as solid-state sensitive membranes of ion selective electrodes (ISEs). In previous works, we have shown that ISEs with ionic conductive AgGeSe membranes have good sensitivity to Ag+ ions. In the present work, we explore the Agx(Ge0.25Se0.75)100-x, 10≤x≤30 (at%) system as candidate for ISEs applications detecting several other ions (K+, Mg2+, Cr3+, Fe3+, Ni2+, Cd2+, Hg2+, and Pb2+). We evaluated ISEs fabricated with bulk as well as with thin film membranes. We found no dependence of the sensing properties on the Ag content of the ionic conductive membranes. Thin films exhibited the same properties than bulk membranes, indicating that these chalcogenide glasses have great potential for miniaturization. The ISEs showed a high response (Nernstian or super-Nernstian) to the presence of Hg2+, Pb2+, and Fe3+, a low response (sub-Nernstian) to the presence of Cr3+, and a total lack of response to the presence of Cd2+, Ni2+, Mg2+, and K+. We also tested how the pH of the solution affected the response of the ISEs. The potentials of the ISEs were practically constant in neutral or acidic solutions, while decreased drastically in basic solutions when the primary ion was not present. The latter phenomenon was caused by the slow dissolution of the membrane into the solution, meaning that long-term basic environments should be avoided for these ISEs. We concluded that ISEs with ionic conductive AgGeSe membranes are good candidates to integrate multi-electrode systems.

  6. Highly sensitive and selective spectrophotometric and spectrofluorimetric methods for the determination of ropinirole hydrochloride in tablets

    NASA Astrophysics Data System (ADS)

    Aydoğmuş, Zeynep

    2008-06-01

    Three sensitive, selective, accurate spectrophotometric and spectrofluorimetric methods have been developed for the determination of ropinirole hydrochloride in tablets. The first method was based on measuring the absorbance of drug solution in methanol at 250 nm. The Beer's law was obeyed in the concentration range 2.5-24 μg ml -1. The second method was based on the charge transfer reaction of drug, as n-electron donor with 7,7,8,8-tetracyanoquinodimethane (TCNQ), as π-acceptor in acetonitrile to give radical anions that are measured at 842 nm. The Beer's law was obeyed in the concentration range 0.6-8 μg ml -1. The third method was based on derivatization reaction with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in borate buffer of pH 8.5 followed by measuring the fluorescence intensity at 525 nm with excitation at 464 nm in chloroform. Beer's law was obeyed in the concentration range 0.01-1.3 μg ml -1. The derivatization reaction product of drug with NBD-Cl was characterized by IR, 1H NMR and mass spectroscopy. The developed methods were validated. The following analytical parameters were investigated: the molar absorptivity ( ɛ), limit of detection (LOD, μg ml -1) and limit of quantitation (LOQ, μg ml -1), precision, accuracy, recovery, and Sandell's sensitivity. Selectivity was validated by subjecting stock solution of ropinirole to acidic, basic, oxidative, and thermal degradation. No interference was observed from common excipients present in formulations. The proposed methods were successfully applied for determination of drug in tablets. The results of these proposed methods were compared with each other statistically.

  7. Potent and highly selective human immunodeficiency virus type 1 (HIV-1) inhibition by a series of alpha-anilinophenylacetamide derivatives targeted at HIV-1 reverse transcriptase.

    PubMed Central

    Pauwels, R; Andries, K; Debyser, Z; Van Daele, P; Schols, D; Stoffels, P; De Vreese, K; Woestenborghs, R; Vandamme, A M; Janssen, C G

    1993-01-01

    In vitro evaluation of a large chemical library of pharmacologically acceptable prototype compounds in a high-capacity, cellular-based screening system has led to the discovery of another family of human immunodeficiency virus type 1 (HIV-1) inhibitors. Through optimization of a lead compound, several alpha-anilinophenylacetamide (alpha-APA) derivatives have been identified that inhibit the replication of several HIV-1 strains (IIIB/LAI, RF, NDK, MN, HE) in a variety of host cell types at concentrations that are 10,000- to 100,000-fold lower than their cytotoxic concentrations. The IC50 of the alpha-APA derivative R 89439 for HIV-1 cytopathicity in MT-4 cells was 13 nM. The median 90% inhibitory concentration (IC90) in a variety of host cells was 50-100 nM. Although these alpha-APA derivatives are active against a tetrahydroimidazo [4,5,1-jk][1,4]benzodiazepin-2(1H)-thione-(TIBO)-resistant HIV-1 strain, they do not inhibit replication of HIV-2 (strains ROD and EHO) or simian immunodeficiency virus (strains Mac251, mndGB1, and agm3). An HIV-1 strain containing the Tyr181-->Cys mutation in the reverse transcriptase region displayed reduced sensitivity. alpha-APA derivative R 89439 inhibited virion and recombinant reverse transcriptase of HIV-1 but did not inhibit that of HIV-2. Reverse transcriptase inhibition depended upon the template/primer used. The relatively uncomplicated synthesis of R 89439, its potent anti-HIV-1 activity, and its favorable pharmacokinetic profile make R 89439 a good candidate for clinical studies. PMID:7680476

  8. Global sensitivity analysis approach for input selection and system identification purposes--a new framework for feedforward neural networks.

    PubMed

    Fock, Eric

    2014-08-01

    A new algorithm for the selection of input variables of neural network is proposed. This new method, applied after the training stage, ranks the inputs according to their importance in the variance of the model output. The use of a global sensitivity analysis technique, extended Fourier amplitude sensitivity test, gives the total sensitivity index for each variable, which allows for the ranking and the removal of the less relevant inputs. Applied to some benchmarking problems in the field of features selection, the proposed approach shows good agreement in keeping the relevant variables. This new method is a useful tool for removing superfluous inputs and for system identification.

  9. Enantiomer-selective pharmacokinetics, oral bioavailability, and sex effects of various alpha-lipoic acid dosage forms.

    PubMed

    Hermann, Robert; Mungo, Julius; Cnota, Peter Jürgen; Ziegler, Dan

    2014-01-01

    The present study aimed to examine the enantiomer-selective pharmacokinetics (PK), relative bioavailability (Frel), and sex effects of various oral dosage forms of racemic alpha-lipoic acid (ALA). In an open-label, randomized, four-period, four-sequence crossover study, 24 healthy adult subjects (12 males and 12 females) received single doses of 600 mg of ALA in fasted state at four different occasions as follows: three 200 mg tablets (T 200); two 300 mg tablets (T 300); one 600 mg tablet (T 600); and a racemic ALA solution (OS). All tablet formulations (Thioctacid HR) were considered test treatments, while the OS (Thioctacid, 600 T) served as the reference treatment. Serial blood samples were collected over 8 hours postdose to quantify R-(+)- and S-(-)-ALA enantiomer plasma concentrations for the PK evaluation. The maximum observed plasma concentration (Cmax) and total exposure (area under the curve [AUC]0-t) were compared between treatments by analysis of variance. Weight-normalized Cmax and the AUC data of male and female study subjects were applied to examine the presence of sex effects. All treatments displayed rapid absorption of both enantiomers with median time to maximum concentration (tmax) values ranging from 0.33-0.5 hours. The Frel of all tablet formulations was comparable, with R-(+)-enantiomer Cmax test/reference ratios ranging from 36% (T 600) to 43% (T 200), and R-(+)-enantiomer AUC test/reference ratios ranging from 64% (T 600) to 79% (T 300), indicating a favorable Frel of all tablet formulations, especially in terms of the total extent of absorption (AUC). An examination of weight-normalized female/male Cmax and AUC sex ratios for both ALA enantiomers indicated the absence of a significant sex effect for Cmax, as well as 20%-26% and 25%-32% higher R-(+)- and S-(-)-ALA enantiomer AUC outcomes in females when compared to males. The observed modest sex effect was comparable for both ALA enantiomers and across all formulations, and it did not appear

  10. Reactive chromophores for sensitive and selective detection of chemical warfare agents

    NASA Astrophysics Data System (ADS)

    Frye-Mason, Greg; Leuschen, Martin; la Grone, Marcus; Wald, Lara; Aker, Craig; Dock, Matt; Hancock, Lawrence F.; Fagan, Steve; Paul, Kateri

    2004-08-01

    A new sensor for highly toxic species including chemical warfare (CW) agents has been developed. This sensor is based on a unique CW indicating chromophore (CWIC) developed by Professor Tim Swager at MIT. The CWIC was designed to be sensitive to the reactivity that makes these chemicals so toxic. Since it requires the reactivity of the agent to be detected, the CWIC technology has shown remarkable selectivity for nerve agent surrogates and some other highly toxic species, thereby demonstrating the potential to provide low false alarm rate detection. Since the chromophore has mini-mal fluorescence prior to reaction with an electrophilic and toxic chemical, the sensor acts in a dark field fluorescence mode. This provides the sensor with exceptional sensitivity and a potential to detect priority analytes well below levels detected by current hand held sensors. Finally, it is based on a simple optical detection scheme that enables small and rugged sensors to be developed and produced at a low enough cost so they can be widely utilized.

  11. Long-Term Memories Bias Sensitivity and Target Selection in Complex Scenes

    PubMed Central

    Patai, Eva Zita; Doallo, Sonia; Nobre, Anna Christina

    2014-01-01

    In everyday situations we often rely on our memories to find what we are looking for in our cluttered environment. Recently, we developed a new experimental paradigm to investigate how long-term memory (LTM) can guide attention, and showed how the pre-exposure to a complex scene in which a target location had been learned facilitated the detection of the transient appearance of the target at the remembered location (Summerfield, Lepsien, Gitelman, Mesulam, & Nobre, 2006; Summerfield, Rao, Garside, & Nobre, 2011). The present study extends these findings by investigating whether and how LTM can enhance perceptual sensitivity to identify targets occurring within their complex scene context. Behavioral measures showed superior perceptual sensitivity (d′) for targets located in remembered spatial contexts. We used the N2pc event-related potential to test whether LTM modulated the process of selecting the target from its scene context. Surprisingly, in contrast to effects of visual spatial cues or implicit contextual cueing, LTM for target locations significantly attenuated the N2pc potential. We propose that the mechanism by which these explicitly available LTMs facilitate perceptual identification of targets may differ from mechanisms triggered by other types of top-down sources of information. PMID:23016670

  12. Fabrication of an electrochemical sensor based on spiropyran for sensitive and selective detection of fluoride ion.

    PubMed

    Tao, Jia; Zhao, Peng; Li, Yinhui; Zhao, Wenjie; Xiao, Yue; Yang, Ronghua

    2016-04-28

    In the past decades, numerous electrochemical sensors based on exogenous electroactive substance have been reported. Due to non-specific interaction between the redox mediator and the target, the instability caused by false signal may not be avoided. To address this issue, in this paper, a new electrochemical sensor based on spiropyran skeleton, namely SPOSi, was designed for specific electrochemical response to fluoride ions (F(-)). The breakage of Si-O induced by F(-) based on the specific nucleophilic substitution reaction between F(-) and silica would directly produce a hydroquinone structure for electrochemical signal generation. To improve the sensitivity, SPOSi probe was assembled on the single-walled carbon nanotubes (SWCNTs) modified glassy carbon electrode (GCE) through the π-π conjugating interaction. This electrode was successfully applied to monitor F(-) with a detection limit of 8.3 × 10(-8) M. Compared with the conventional F(-) ion selected electrode (ISE) which utilized noncovalent interaction, this method displays higher stability and a comparable sensitivity in the urine samples.

  13. Selective Fragmentation of Radiation-Sensitive Novel Polymeric Resist Materials by Inner-Shell Irradiation.

    PubMed

    Chagas, Gabriela Ramos; Satyanarayana, Vardhineedi Sri Venkata; Kessler, Felipe; Belmonte, Guilherme Kretzmann; Gonsalves, Kenneth E; Weibel, Daniel Eduardo

    2015-08-05

    Two key concepts in extreme ultraviolet lithography (EUVL) are important for it to be a candidate for the mass production of future integrated circuits: the polymer formulation and the photofragmentation process. In this work, both concepts were carefully studied. The design and synthesis of radiation-sensitive organic polymeric materials based on the inclusion of a radiation-sensitive tetrahydrothiophenium functional group are outlined. A 1-(4-methacryloyoxy)naphthalene-1-yl)tetrahydro-1H-thiophenium trifluoromethanesulfonate (MANTMS) monomer containing the tetrahydrothiophenium group undergoes homo- and copolymerizations using free-radical polymerization with a 2,2'-azobis(isobutyronitrile) initiator. The surface photodegradation and oxidation of these novel polymeric materials were investigated using highly monochromatized soft X-rays from synchrotron radiation at the carbon K-edge excitation region. An efficient functionalization was observed when the excitation energy was tuned to C 1s → π*C═C. A high rate of defluorination and a loss of sulfonated groups as a result of an increase in the irradiation time for the MANTMS homopolymer thin films were mainly observed under the π*C═C excitation of the naphthyl functional groups. On the contrary, excitation similar to C 1s → π*C═O or C 1s → σ*C-F did not produce important degradation, showing a highly selective process of bond breaking. Additionally, the presence of methyl methacrylate copolymer in the original MANTMS yielded a much higher degree of stability against inner-shell radiation damage. Our results highlight the importance of choosing the right polymer formulation and excitation energy to produce a sensitive material for EUVL without using the concept of chemical amplification.

  14. Imaging alpha particle detector

    DOEpatents

    Anderson, David F.

    1985-01-01

    A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  15. Imaging alpha particle detector

    DOEpatents

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  16. Organocatalysed asymmetric beta-amination and multicomponent syn-selective diamination of alpha,beta-unsaturated aldehydes.

    PubMed

    Jiang, Hao; Nielsen, Johanne B; Nielsen, Martin; Jørgensen, Karl Anker

    2007-01-01

    An easy and affordable route for obtaining chiral beta-aminated- and alpha,beta-diaminated aldehydes, 1,3-aminoalcohols, and related compounds by using organocatalysis is presented. The chiral secondary amine (S)-2-[bis(3,5-bistrifluoromethylphenyl)trimethylsilanyloxymethyl]pyrrolidine is used as the catalyst to activate alpha,beta-unsaturated aldehydes, which allows succinimide to add in a 1,4-regio- and stereoselective fashion thereby forming N-protected 1,3-aminoaldehydes in good yields and enantioselectivities. This is followed by two easy transformations giving rise to optically active 1,3-aminoalcohols, a common motif in many biologically active compounds, for example, fibrinogen receptor antagonists. Furthermore, optically active alpha,beta-syn-diaminated aldehydes were obtained by the addition of diethyl azodicarboxylate in a one-pot reaction.

  17. Tumor Necrosis Factor Alpha Inhibits L-Type Ca(2+) Channels in Sensitized Guinea Pig Airway Smooth Muscle through ERK 1/2 Pathway.

    PubMed

    Reyes-García, Jorge; Flores-Soto, Edgar; Solís-Chagoyán, Héctor; Sommer, Bettina; Díaz-Hernández, Verónica; García-Hernández, Luz María; Montaño, Luis M

    2016-01-01

    Tumor necrosis factor alpha (TNF-α) is a potent proinflammatory cytokine that plays a significant role in the pathogenesis of asthma by inducing hyperresponsiveness and airway remodeling. TNF-α diminishes the L-type voltage dependent Ca(2+) channel (L-VDCC) current in cardiac myocytes, an observation that seems paradoxical. In guinea pig sensitized tracheas KCl responses were lower than in control tissues. Serum from sensitized animals (Ser-S) induced the same phenomenon. In tracheal myocytes from nonsensitized (NS) and sensitized (S) guinea pigs, an L-VDCC current (ICa) was observed and diminished by Ser-S. The same decrease was detected in NS myocytes incubated with TNF-α, pointing out that this cytokine might be present in Ser-S. We observed that a small-molecule inhibitor of TNF-α (SMI-TNF) and a TNF-α receptor 1 (TNFR1) antagonist (WP9QY) reversed ICa decrease induced by Ser-S in NS myocytes, confirming the former hypothesis. U0126 (a blocker of ERK 1/2 kinase) also reverted the decrease in ICa. Neither cycloheximide (a protein synthesis inhibitor) nor actinomycin D (a transcription inhibitor) showed any effect on the TNF-α-induced ICa reduction. We found that CaV1.2 and CaV1.3 mRNA and proteins were expressed in tracheal myocytes and that sensitization did not modify them. In cardiac myocytes, ERK 1/2 phosphorylates two sites of the L-VDCC, augmenting or decreasing ICa; we postulate that, in guinea pig tracheal smooth muscle, TNF-α diminishes ICa probably by phosphorylating the L-VDCC site that reduces its activity through the ERK1/2 MAP kinase pathway.

  18. Tumor Necrosis Factor Alpha Inhibits L-Type Ca2+ Channels in Sensitized Guinea Pig Airway Smooth Muscle through ERK 1/2 Pathway

    PubMed Central

    Reyes-García, Jorge; Flores-Soto, Edgar; Solís-Chagoyán, Héctor; Sommer, Bettina; Díaz-Hernández, Verónica; García-Hernández, Luz María

    2016-01-01

    Tumor necrosis factor alpha (TNF-α) is a potent proinflammatory cytokine that plays a significant role in the pathogenesis of asthma by inducing hyperresponsiveness and airway remodeling. TNF-α diminishes the L-type voltage dependent Ca2+ channel (L-VDCC) current in cardiac myocytes, an observation that seems paradoxical. In guinea pig sensitized tracheas KCl responses were lower than in control tissues. Serum from sensitized animals (Ser-S) induced the same phenomenon. In tracheal myocytes from nonsensitized (NS) and sensitized (S) guinea pigs, an L-VDCC current (ICa) was observed and diminished by Ser-S. The same decrease was detected in NS myocytes incubated with TNF-α, pointing out that this cytokine might be present in Ser-S. We observed that a small-molecule inhibitor of TNF-α (SMI-TNF) and a TNF-α receptor 1 (TNFR1) antagonist (WP9QY) reversed ICa decrease induced by Ser-S in NS myocytes, confirming the former hypothesis. U0126 (a blocker of ERK 1/2 kinase) also reverted the decrease in ICa. Neither cycloheximide (a protein synthesis inhibitor) nor actinomycin D (a transcription inhibitor) showed any effect on the TNF-α-induced ICa reduction. We found that CaV1.2 and CaV1.3 mRNA and proteins were expressed in tracheal myocytes and that sensitization did not modify them. In cardiac myocytes, ERK 1/2 phosphorylates two sites of the L-VDCC, augmenting or decreasing ICa; we postulate that, in guinea pig tracheal smooth muscle, TNF-α diminishes ICa probably by phosphorylating the L-VDCC site that reduces its activity through the ERK1/2 MAP kinase pathway. PMID:27445440

  19. Sensitivity of the Assimilated Ozone in the UTLS to Model and Data Selection Changes

    NASA Technical Reports Server (NTRS)

    Pawson, Steven; Stajner, Ivanka; Wargan, Krzysztof; Rood, Richard

    2003-01-01

    This presentation will discuss the sensitivity of assimilated ozone fields in the upper troposphere and lower stratosphere (UTLS) to a number of factors, focusing mainly on aspects of data selection and the prediction model. This is important, because assimilation represents an attempt to construct our best estimates of the true ozone field; however, inaccuracies in the UTLS ozone distribution translate into an uncertainty in factors such as the calculated radiative forcing of climate or the inferred stratosphere-troposphere exchange (STE) of ozone. The 3D ozone data assimilation system, from NASA's Global Modeling and Assimilation Office (GMAO), combines observations of total ozone column and stratospheric profiles with predictions from an off-line, parameterized chemistry and transport model (pCTM) to produce six-hourly, global analyses. The first experiments discussed assimilate ozone retrievals from the Earth-Probe Total Ozone Mapping Spectrometer (EPTOMS) and stratospheric profiles from the Solar Backscatter UltraViolet/2 (SBUV/2) instrument. The SBUV/2 ozone data have a coarse vertical resolution, with increased uncertainty below the ozone maximum, and TOMS provides only total ozone columns. Thus, the assimilated ozone profiles in the UTLS region are only weakly constrained by the incoming SBUV and TOMS data. Consequently, the assimilated ozone distribution should be sensitive to changes in inputs to the statistical analysis scheme. Sensitivity studies have been conducted to examine the responses to TOMS and SBUV/2 data selection, modifications of the forecast and observation error covariance models, and the model formulation (turning off chemistry or using different wind analyses in the pCTM). The second set of experiments includes an additional data type: ozone retrieved from infrared limb-emission by MIPAS on Envisat. These data offer not only improved vertical resolution in the stratosphere, but also give measurements in the polar night. Comparisons of

  20. A high-sensitivity 2x2 multi-aperture color camera based on selective averaging

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Kagawa, Keiichiro; Takasawa, Taishi; Seo, Min-Woong; Yasutomi, Keita; Kawahito, Shoji

    2015-03-01

    To demonstrate the low-noise performance of the multi-aperture imaging system using a selective averaging method, an ultra-high-sensitivity multi-aperture color camera with 2×2 apertures is being developed. In low-light conditions, random telegraph signal (RTS) noise and dark current white defects become visible, which greatly degrades the quality of the image. To reduce these kinds of noise as well as to increase the number of incident photons, the multi-aperture imaging system composed of an array of lens and CMOS image sensor (CIS), and the selective averaging for minimizing the synthetic sensor noise at every pixel is utilized. It is verified by simulation that the effective noise at the peak of noise histogram is reduced from 1.44 e- to 0.73 e- in a 2×2-aperture system, where RTS noise and dark current white defects have been successfully removed. In this work, a prototype based on low-noise color sensors with 1280×1024 pixels fabricated in 0.18um CIS technology is considered. The pixel pitch is 7.1μm×7.1μm. The noise of the sensor is around 1e- based on the folding-integration and cyclic column ADCs, and the low voltage differential signaling (LVDS) is used to improve the noise immunity. The synthetic F-number of the prototype is 0.6.

  1. Purifying Selection Maintains Dosage-Sensitive Genes during Degeneration of the Threespine Stickleback Y Chromosome

    PubMed Central

    White, Michael A.; Kitano, Jun; Peichel, Catherine L.

    2015-01-01

    Sex chromosomes are subject to unique evolutionary forces that cause suppression of recombination, leading to sequence degeneration and the formation of heteromorphic chromosome pairs (i.e., XY or ZW). Although progress has been made in characterizing the outcomes of these evolutionary processes on vertebrate sex chromosomes, it is still unclear how recombination suppression and sequence divergence typically occur and how gene dosage imbalances are resolved in the heterogametic sex. The threespine stickleback fish (Gasterosteus aculeatus) is a powerful model system to explore vertebrate sex chromosome evolution, as it possesses an XY sex chromosome pair at relatively early stages of differentiation. Using a combination of whole-genome and transcriptome sequencing, we characterized sequence evolution and gene expression across the sex chromosomes. We uncovered two distinct evolutionary strata that correspond with known structural rearrangements on the Y chromosome. In the oldest stratum, only a handful of genes remain, and these genes are under strong purifying selection. By comparing sex-linked gene expression with expression of autosomal orthologs in an outgroup, we show that dosage compensation has not evolved in threespine sticklebacks through upregulation of the X chromosome in males. Instead, in the oldest stratum, the genes that still possess a Y chromosome allele are enriched for genes predicted to be dosage sensitive in mammals and yeast. Our results suggest that dosage imbalances may have been avoided at haploinsufficient genes by retaining function of the Y chromosome allele through strong purifying selection. PMID:25818858

  2. FTIR gas analysis with improved sensitivity and selectivity for CWA and TIC detection

    NASA Astrophysics Data System (ADS)

    Phillips, Charles M.; Tan, Huwei

    2010-04-01

    This presentation describes the use of an FTIR (Fourier Transform Infrared)-based spectrometer designed to continuously monitor ambient air for the presence of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs). The necessity of a reliable system capable of quickly and accurately detecting very low levels of CWAs and TICs while simultaneously retaining a negligible false alarm rate will be explored. Technological advancements in FTIR sensing have reduced noise while increasing selectivity and speed of detection. These novel analyzer design characteristics are discussed in detail and descriptions are provided which show how optical throughput, gas cell form factor, and detector response are optimized. The hardware and algorithms described here will explain why this FTIR system is very effective for the simultaneous detection and speciation of a wide variety of toxic compounds at ppb concentrations. Analytical test data will be reviewed demonstrating the system's sensitivity to and selectivity for specific CWAs and TICs; this will include recent data acquired as part of the DHS ARFCAM (Autonomous Rapid Facility Chemical Agent Monitor) project. These results include analyses of the data from live agent testing for the determination of CWA detection limits, immunity to interferences, detection times, residual noise analysis and false alarm rates. Sensing systems such as this are critical for effective chemical hazard identification which is directly relevant to the CBRNE community.

  3. Highly sensitive and selective WO3 nanoparticle gas sensor operating in thermally modulated dynamic mode

    NASA Astrophysics Data System (ADS)

    Ionescu, Radu; Hoel, Anders; Granqvist, Claes-Goran; Llobet, Eduard; Heszler, Peter

    2004-05-01

    Nanoparticle films of crystalline WO3, designed for gas sensing applications, were deposited on alumina substrates by reactive gas deposition. H2S, ethanol vapour, and binary mixtures of ethanol/H2S, ethanol/NO2 and H2S/NO2 were used in different concentrations for testing the performance of the sensor device. The sensor was operated in dynamic mode by modulating its temperature between 150 and 250 °C. Coefficients were extracted by applying Fast Fourier Transform (FFT) and Discrete Wavelet Transform (DWT) methods to the dynamic resistance response of the sensor. These coefficients were then used as inputs for pattern recognition methods to extract both quantitative (concentration) and qualitative (chemical selectivity) information about the test gases. After sensor calibration, it was possible to detect as little as 200 ppb of ethanol and 20 ppb of H2S with good accuracy. Furthermore, ethanol and H2S could be detected with good sensitivity and selectivity in the presence of both reducing and oxidising gases.

  4. Molecular engineering of a fluorescent bioprobe for sensitive and selective detection of amphibole asbestos.

    PubMed

    Ishida, Takenori; Alexandrov, Maxym; Nishimura, Tomoki; Hirota, Ryuichi; Ikeda, Takeshi; Kuroda, Akio

    2013-01-01

    Fluorescence microscopy-based affinity assay could enable highly sensitive and selective detection of airborne asbestos, an inorganic environmental pollutant that can cause mesothelioma and lung cancer. We have selected an Escherichia coli histone-like nucleoid structuring protein, H-NS, as a promising candidate for an amphibole asbestos bioprobe. H-NS has high affinity to amphibole asbestos, but also binds to an increasingly common asbestos substitute, wollastonite. To develop a highly specific Bioprobe for amphibole asbestos, we first identified a specific but low-affinity amosite-binding sequence by slicing H-NS into several fragments. Second, we constructed a streptavidin tetramer complex displaying four amosite-binding fragments, resulting in the 250-fold increase in the probe affinity as compared to the single fragment. The tetramer probe had sufficient affinity and specificity for detecting all the five types of asbestos in the amphibole group, and could be used to distinguish them from wollastonite. In order to clarify the binding mechanism and identify the amino acid residues contributing to the probe's affinity to amosite fibers, we constructed a number of shorter and substituted peptides. We found that the probable binding mechanism is electrostatic interaction, with positively charged side chains of lysine residues being primarily responsible for the probe's affinity to asbestos.

  5. A Sensitive Secondary Users Selection Algorithm for Cognitive Radio Ad Hoc Networks

    PubMed Central

    Li, Aohan; Han, Guangjie; Wan, Liangtian; Shu, Lei

    2016-01-01

    Secondary Users (SUs) are allowed to use the temporarily unused licensed spectrum without disturbing Primary Users (PUs) in Cognitive Radio Ad Hoc Networks (CRAHNs). Existing architectures for CRAHNs impose energy-consuming Cognitive Radios (CRs) on SUs. However, the advanced CRs will increase energy cost for their cognitive functionalities, which is undesirable for the battery powered devices. A new architecture referred to as spectral Requirement-based CRAHN (RCRAHN) is proposed to enhance energy efficiency for CRAHNs in this paper. In RCRAHNs, only parts of SUs are equipped with CRs. SUs equipped with CRs are referred to as Cognitive Radio Users (CRUs). To further enhance energy efficiency of CRAHNs, we aim to select minimum CRUs to sense available spectrum. A non-linear programming problem is mathematically formulated under the constraints of energy efficiency and real-time. Considering the NP-hardness of the problem, a framework of a heuristic algorithm referred to as Sensitive Secondary Users Selection (SSUS) was designed to compute the near-optimal solutions. The simulation results demonstrate that SSUS not only improves the energy efficiency, but also achieves satisfied performances in end-to-end delay and communication reliability. PMID:27023562

  6. Selective allergy to lobster in a case of primary sensitization to house dust mites.

    PubMed

    Iparraguirre, A; Rodríguez-Pérez, R; Juste, S; Ledesma, A; Moneo, I; Caballero, M L

    2009-01-01

    Allergy to only 1 kind of seafood is uncommon. We report a case of selective allergy to lobster. We studied a 30-year-old man who suffered generalized urticaria, facial erythema, and pharyngeal pruritus after eating lobster. He had a more than 10-year history of mild persistent asthma and sensitization to house dust mites. The study was performed by skin prick test, and prick-prick test, oral food challenge, specific immunoglobulin (Ig) E determinations by CAP (Phadia, Uppsala, Sweden) and ADVIA-Centaur (ALK-Abelló, Madrid, Spain), and IgE-immunoblotting. The patient's serum recognized 2 allergens of around 198 kDa and 2 allergens of around 65 kDa from the lobster extract, allergens of around 15, 90, and 120 kDa from Dermatophagoides pteronyssinus extract, and allergens of around 15 and 65 kDa from Dermatophagoides farinae extract. Serum did not recognize purified shrimp tropomyosin. Immunoblot-inhibition assay results indicated cross-reactivity between lobster and mite allergens. This is the first report of selective allergy to lobster.

  7. Human mast cells transmigrate through human umbilical vein endothelial monolayers and selectively produce IL-8 in response to stromal cell-derived factor-1 alpha.

    PubMed

    Lin, T J; Issekutz, T B; Marshall, J S

    2000-07-01

    Mature mast cells are generally considered to be less mobile cells residing within tissue sites. However, mast cell numbers are known to increase in the context of inflammation, and mast cells are recognized to be important in regulating local neutrophil infiltration. CXC chemokines may play a critical role in this process. In this study two human mast cell-like lines, HMC-1 and KU812, and human cord blood-derived primary cultured mast cells were employed to examine role of stromal cell-derived factor-1 (SDF-1) in regulating mast cell migration and mediator production. It was demonstrated that human mast cells constitutively express mRNA and protein for CXCR4. Stimulation of human mast cells with SDF-1, the only known ligand for CXCR4, induced a significant increase in intracellular calcium levels. In vitro, SDF-1 alpha mediated dose-dependent migration of human cord blood-derived mast cells and HMC-1 cells across HUVEC monolayers. Although SDF-1 alpha did not induce mast cell degranulation, it selectively stimulated production of the neutrophil chemoattractant IL-8 without affecting TNF-alpha, IL-1beta, IL-6, GM-CSF, IFN-gamma, or RANTES production, providing further evidence of the selective modulation of mast cell function by this chemokine. These findings provide a novel, SDF-1-dependent mechanism for mast cell transendothelial migration and functional regulation, which may have important implications for the local regulation of mast cells in disease.

  8. Development of selectivity of alpha1-antitrypsin variant by mutagenesis in its reactive site loop against proprotein convertase. A crucial role of the P4 arginine in PACE4 inhibition.

    PubMed

    Tsuji, Akihiko; Ikoma, Takayuki; Hashimoto, Emi; Matsuda, Yoshiko

    2002-02-01

    PACE4, furin and PC6 are Ca2+-dependent serine endoproteases that belong to the subtilisin-like proprotein convertase (SPC) family. Recent reports have supported the involvement of these enzymes in processing of growth/differentiation factors, viral replication, activation of bacterial toxins and tumorigenesis, indicating that these enzymes are a fascinating target for therapeutic agents. In this work, we evaluated the sensitivity and selectivity of three rat alpha1-antitrypsin variants which contained RVPR352, AVRR352 and RVRR352, respectively, within their reactive site loop using both inhibition of enzyme activity toward a fluorogenic substrate in vitro and formation of a SDS-stable protease/inhibitor complex ex vivo. The RVPR variant showed relatively broad selectivity, whereas the AVRR and RVRR variants were more selective than the RVPR variant. The AVRR variant inhibited furin and PC6 but not PACE4. This selectivity was further confirmed by complex formation and inhibition of pro-complement C3 processing. On the other hand, although the RVRR variant inhibited both PACE4 and furin effectively, it needed a 600-fold higher concentration than the RVPR variant to inhibit PC6 in vitro. These inhibitors will be useful tools in helping us to understand the roles of PACE4, furin and PC6.

  9. SynLethDB: synthetic lethality database toward discovery of selective and sensitive anticancer drug targets.

    PubMed

    Guo, Jing; Liu, Hui; Zheng, Jie

    2016-01-04

    Synthetic lethality (SL) is a type of genetic interaction between two genes such that simultaneous perturbations of the two genes result in cell death or a dramatic decrease of cell viability, while a perturbation of either gene alone is not lethal. SL reflects the biologically endogenous difference between cancer cells and normal cells, and thus the inhibition of SL partners of genes with cancer-specific mutations could selectively kill cancer cells but spare normal cells. Therefore, SL is emerging as a promising anticancer strategy that could potentially overcome the drawbacks of traditional chemotherapies by reducing severe side effects. Researchers have developed experimental technologies and computational prediction methods to identify SL gene pairs on human and a few model species. However, there has not been a comprehensive database dedicated to collecting SL pairs and related knowledge. In this paper, we propose a comprehensive database, SynLethDB (http://histone.sce.ntu.edu.sg/SynLethDB/), which contains SL pairs collected from biochemical assays, other related databases, computational predictions and text mining results on human and four model species, i.e. mouse, fruit fly, worm and yeast. For each SL pair, a confidence score was calculated by integrating individual scores derived from different evidence sources. We also developed a statistical analysis module to estimate the druggability and sensitivity of cancer cells upon drug treatments targeting human SL partners, based on large-scale genomic data, gene expression profiles and drug sensitivity profiles on more than 1000 cancer cell lines. To help users access and mine the wealth of the data, we developed other practical functionalities, such as search and filtering, orthology search, gene set enrichment analysis. Furthermore, a user-friendly web interface has been implemented to facilitate data analysis and interpretation. With the integrated data sets and analytics functionalities, SynLethDB would

  10. Sensitivity of Lower Stratospheric Assimilated Ozone on Error Covariance Modeling and Data Selection

    NASA Technical Reports Server (NTRS)

    Stajner, Ivanka; Rood, Richard B.; Winslow, Nathan; Wargan, Krzysztof; Pawson, Steven

    2002-01-01

    Assimilated ozone is produced at the NASA/Goddard Data Assimilation Office by blending ozone retrieved from the Solar Backscatter UltraViolet/2 (SBUV/2) instrument and the Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) measurements into an off-line transport model. The current system tends to overestimate the amount of lower stratospheric ozone. This is a region where ozone plays a key role in the forcing of climate. A biased ozone field in this region will adversely impact calculations of the stratosphere-troposphere exchange and, when used as a first guess in retrievals, the values determined from satellite observations. Since these are all important applications of assimilated ozone products, effort is being directed towards reducing this bias. The SBUV ozone data have a coarse vertical resolution with increased uncertainty below the ozone maximum, and TOMS provides only total ozone columns. Thus, the assimilated ozone in the lower stratosphere, and its vertical distribution in particular, are only weakly constrained by the incoming SBUV and TOMS data. Consequently, the assimilated ozone distribution should be sensitive to changes in inputs to the statistical analysis scheme. Accordingly, the sensitivity of the assimilated lower stratospheric ozone fields to changes in the TOMS error-covariance modeling and the SBUV data selection has been investigated. The use of a spatially correlated TOMS error covariance model led to improvements in the product. However, withholding the SBUV/2 data for the layer between 63 and 126 hPa typically degraded the product, a result which vindicates the use of this layer ozone product, despite its known errors. These efforts to improve the lower stratospheric distribution will be extended to include a more advanced forecast error covariance model, and by assimilating ozone products from new instruments on Envisat and EOS Aura.

  11. Elucidating the Complex Lineshapes Resulting from the Highly Sensitive, Ion Selective, Technique Nice-Ohvms

    NASA Astrophysics Data System (ADS)

    Hodges, James N.; Siller, Brian; McCall, Benjamin J.

    2015-06-01

    The technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy, or NICE-OHVMS, has been used to great effect to precisely and accurately measure a variety of molecular ion transitions from species such as H_3^+, CH_5^+, HeH^+, and HCO^+, achieving MHz or in some cases sub-MHz uncertainty. It is a powerful technique, but a complete theoretical understanding of the complex NICE-OHVMS lineshape is needed to fully unlock its potential. NICE-OHVMS is the direct result of the combination of the highly sensitive spectroscopic technique Noise Immune Cavity Enhanced Optical Heterodyne Molecular Spectroscopy(NICE-OHMS) with Velocity Modulation Spectroscopy(VMS), applying the most sensitive optical detection method with ion species selectivity. The theoretical underpinnings of NICE-OHMS lineshapes are well established, as are those of VMS. This presentation is the logical extension of those two preceding bodies of work. Simulations of NICE-OHVMS lineshapes under a variety of conditions and fits of experimental data to the model are presented. The significance and accuracy of the various inferred parameters, along with the prospect of using them to extract additional information from observed transitions, are discussed. J.~N. Hodges, et al. J. Chem. Phys. (2013), 139, 164201. A.~J. Perry, et al. J. Chem. Phys. (2014), 141, 101101. K.~N. Crabtree, et al. Chem. Phys. Lett. (2012), 551, 1-6. F.~M. Schmidt, et al. J. Opt. Soc. Amer. A (2008), 24, 1392--1405. J.~W. Farley, J. Chem. Phys. (1991), 95, 5590--5602.

  12. Cortical Granule Exocytosis Is Mediated by Alpha-SNAP and N-Ethilmaleimide Sensitive Factor in Mouse Oocytes.

    PubMed

    de Paola, Matilde; Bello, Oscar Daniel; Michaut, Marcela Alejandra

    2015-01-01

    Cortical granule exocytosis (CGE), also known as cortical reaction, is a calcium- regulated secretion that represents a membrane fusion process during meiotic cell division of oocytes. The molecular mechanism of membrane fusion during CGE is still poorly understood and is thought to be mediated by the SNARE pathway; nevertheless, it is unkown if SNAP (acronym for soluble NSF attachment protein) and NSF (acronym for N-ethilmaleimide sensitive factor), two key proteins in the SNARE pathway, mediate CGE in any oocyte model. In this paper, we documented the gene expression of α-SNAP, γ-SNAP and NSF in mouse oocytes. Western blot analysis showed that the expression of these proteins maintains a similar level during oocyte maturation and early activation. Their localization was mainly observed at the cortical region of metaphase II oocytes, which is enriched in cortical granules. To evaluate the function of these proteins in CGE we set up a functional assay based on the quantification of cortical granules metaphase II oocytes activated parthenogenetically with strontium. Endogenous α-SNAP and NSF proteins were perturbed by microinjection of recombinant proteins or antibodies prior to CGE activation. The microinjection of wild type α-SNAP and the negative mutant of α-SNAP L294A in metaphase II oocytes inhibited CGE stimulated by strontium. NEM, an irreversibly inhibitor of NSF, and the microinjection of the negative mutant NSF D1EQ inhibited cortical reaction. The microinjection of anti-α-SNAP and anti-NSF antibodies was able to abolish CGE in activated metaphase II oocytes. The microinjection of anti-γ SNAP antibody had no effect on CGE. Our findings indicate, for the first time in any oocyte model, that α-SNAP, γ-SNAP, and NSF are expressed in mouse oocytes. We demonstrate that α-SNAP and NSF have an active role in CGE and propose a working model.

  13. Cortical Granule Exocytosis Is Mediated by Alpha-SNAP and N-Ethilmaleimide Sensitive Factor in Mouse Oocytes

    PubMed Central

    de Paola, Matilde; Bello, Oscar Daniel; Michaut, Marcela Alejandra

    2015-01-01

    Cortical granule exocytosis (CGE), also known as cortical reaction, is a calcium- regulated secretion that represents a membrane fusion process during meiotic cell division of oocytes. The molecular mechanism of membrane fusion during CGE is still poorly understood and is thought to be mediated by the SNARE pathway; nevertheless, it is unkown if SNAP (acronym for soluble NSF attachment protein) and NSF (acronym for N-ethilmaleimide sensitive factor), two key proteins in the SNARE pathway, mediate CGE in any oocyte model. In this paper, we documented the gene expression of α-SNAP, γ-SNAP and NSF in mouse oocytes. Western blot analysis showed that the expression of these proteins maintains a similar level during oocyte maturation and early activation. Their localization was mainly observed at the cortical region of metaphase II oocytes, which is enriched in cortical granules. To evaluate the function of these proteins in CGE we set up a functional assay based on the quantification of cortical granules metaphase II oocytes activated parthenogenetically with strontium. Endogenous α-SNAP and NSF proteins were perturbed by microinjection of recombinant proteins or antibodies prior to CGE activation. The microinjection of wild type α-SNAP and the negative mutant of α-SNAP L294A in metaphase II oocytes inhibited CGE stimulated by strontium. NEM, an irreversibly inhibitor of NSF, and the microinjection of the negative mutant NSF D1EQ inhibited cortical reaction. The microinjection of anti-α-SNAP and anti-NSF antibodies was able to abolish CGE in activated metaphase II oocytes. The microinjection of anti-γ SNAP antibody had no effect on CGE. Our findings indicate, for the first time in any oocyte model, that α-SNAP, γ-SNAP, and NSF are expressed in mouse oocytes. We demonstrate that α-SNAP and NSF have an active role in CGE and propose a working model. PMID:26267363

  14. Laser selective microablation of sensitized intracellular components within auditory receptor cells

    NASA Astrophysics Data System (ADS)

    Harris, David M.; Evans, Burt N.; Santos-Sacchi, Joseph

    1995-05-01

    A laser system can be coupled to a light microscope for laser microbeam ablation and trapping of single cells in vitro. We have extended this technology by sensitization of target structures with vital dyes to provide selective ablation of specific subcellular components. Isolated auditory receptor cells (outer hair cells, OHCs) are known to elongate and contract in response to electrical, chemical and mechanical stimulation. Various intracellular structures are candidate components mediating motility of OHCs, but the exact mechanism(s) is currently unknown. In ongoing studies of OHC motility, we have used the microbeam for selective ablation of lateral wall components and of an axial cytoskeletal core that extends from the nucleus to the cell apex. Both the area beneath the subsurface cistemae of the lateral wall and the core are rich in mitochondria. OHCs isolated from guinea pig cochlea are suspended in L- 15 medium containing 2.0 (mu) M Rhodamine 123, a porphyrin with an affinity for mitochondria. A spark-pumped nitrogen laser pumping a dye cell (Coumarin 500) was aligned on the optical axis of a Nikon Optiphot-2 to produce a 3 ns, 0.5 - 10 micrometers spot (diameter above ablation threshold w/50X water immersion, N.A. 0.8), and energy at the target approximately equals 10 (mu) J/pulse. At short incubation times in Rh123 irradiation caused local blebbing or bulging of cytoplastic membrane and thus loss of the OHC's cylindrical shape. At longer Rh123 incubation times when the central axis of the cell was targeted we observed cytoplasmic clearing, immediate cell elongation (approximately equals 5%) and clumping of core material at nuclear and apical attachments. Experiments are underway to examine the significance of these preliminary observations.

  15. Effects of iodoproxyfan, a potent and selective histamine H3 receptor antagonist, on alpha 2 and 5-HT3 receptors.

    PubMed

    Schlicker, E; Pertz, H; Bitschnau, H; Purand, K; Kathmann, M; Elz, S; Schunack, W

    1995-07-01

    We determined the affinity and/or potency of the novel H3 receptor antagonist iodoproxyfan at alpha 2 and 5-HT3 receptors. Iodoproxyfan and rauwolscine (a reference alpha 2 ligand) (i) monophasically displaced 3H-rauwolscine binding to rat brain cortex membranes (pKi 6.79 and 8.59); (ii) facilitated the electrically evoked tritium overflow from superfused mouse brain cortex slices preincubated with 3H-noradrenaline (pEC50 6.46 and 7.91) and (iii) produced rightward shifts of the concentration-response curve (CRC) of (unlabelled) noradrenaline for its inhibitory effect on the evoked overflow (pA2 6.65 and 7.88). In the guinea-pig ileum, iodoproxyfan 6.3 mumol/l failed to evoke a contraction by itself but depressed the maximum of the CRC of 5-hydroxytryptamine (pD'2 5.24). Tropisetron (a reference 5-HT3 antagonist) produced rightward shifts of the CRC of 5-hydroxytryptamine (pA2 7.84). In conclusion, the affinity/potency of iodoproxyfan at H3 receptors (range 8.3-9.7 [1]) exceeds that at alpha 2 receptors by at least 1.5 log units and that at 5-HT3 receptors by at least 3 log units.

  16. Enhanced sensitivity and selectivity in a dual cell ion mobility spectrometer

    NASA Astrophysics Data System (ADS)

    Griffin, Matthew T.; Fulton, Jack E., Jr.; McAtee, Robert F.; Gao, Rong; Tsoukalas, Lefteri H.

    2003-08-01

    While ion mobility spectrometry (IMS) has been used as a portable trace vapor detector, these handheld systems suffer from poor selectivity. Their low resolution makes confident identification of chemical species difficult. One major application for these IMS systems is in Homeland Defense. IMS systems are fielded for the detection of chemical warfare agents, explosives, narcotics, and other hazardous chemicals. Recently, a novel signal processing methodology using wavelet filtering, statistical evaluators, and genetic algorithms was demonstrated to improve sensitivity and specificity of an ion mobility spectrometer. Previous work involved a single (single polarity) IMS cell. Since both positive and negative ions are created in the same environment and a common sample interface is used for the dual IMS system, there is cross talk between the positive and negative cell. Typically, this cross talk provides little information on the identity of the chemical species present. However, using this new methodology, valuable sample information is obtained. Moreover, ion beam modulation has been incorporated to allow for the ion beam to be broken up into discrete packets. The modulation allows the rejection of common background interferents. This paper will present the process of using cell cross talk, ion beam modulation, and application and extension of the signal processing methodology. The application to field instrumentation will also be discussed.

  17. Highly selective and sensitized spectrophotometric determination of iron (III) following potentiometric study.

    PubMed

    Shokrollahi, Ardeshir; Ghaedi, Mehrorang; Rajabi, Hamid Reza

    2007-09-01

    A simple, selective and sensitized spectrophotometric method for determination of trace amounts of Fe3+ ion in tap and waste water solutions has been described. The spectrophotometric determination of Fe3+ ion using Ferron in the presence of N,N-Dodecytrimethylammonium bromide (DTAB) has been carried out. The Beer's law is obeyed over the concentration range of 0.05-2.6 microg mL(-1) of Fe3+ ion with the relative standard deviation (RSD %) <0.2% and the molar absorptivity of complexes in pH 3.5 is 3.8 x 10(3) L mol(-1) cm(-1). Potentiometric pH titration has been used for prediction of protonation constants of ferron, and evaluating its stoichiometry and respective stability constant with Fe3+ ion. As it is obvious the most likely species of ferron alone and its complexes are LH (log = 7.64), LH2 (logK = 10.52), LH3 (logK = 11.74) and ML2 (logbeta = 23.68), ML3 (logbeta = 23.68), ML3H (logbeta = 23.68), ML3H2 (logbta = 23.68) and ML(OH)2 (logbeta = 23.68) respectively.

  18. Laser correlation velocimetry performance in diesel applications: spatial selectivity and velocity sensitivity

    NASA Astrophysics Data System (ADS)

    Hespel, Camille; Blaisot, Jean-Bernard; Gazon, Matthieu; Godard, Gilles

    2012-07-01

    The characterization of diesel jets in the near field of the nozzle exit still presents challenges for experimenters. Detailed velocity measurements are needed to characterize diesel injector performance and also to establish boundary conditions for CFD codes. The present article examines the efficiency of laser correlation velocimetry (LCV) applied to diesel spray characterization. A new optical configuration based on a long-distance microscope was tested, and special care was taken to examine the spatial selectivity of the technique. Results show that the depth of the measurement volume (along the laser beam) of LCV extends beyond the depth of field of the imaging setup. The LCV results were also found to be particularly sensitive to high-speed elements of a spray. Results from high-pressure diesel jets in a back-pressure environment indicate that this technique is particularly suited to the very near field of the nozzle exit, where the flow is the narrowest and where the velocity distribution is not too large. It is also shown that the performance of the LCV technique is controlled by the filtering and windowing parameters used in the processing of the raw signals.

  19. A novel bi-enzyme electrochemical biosensor for selective and sensitive determination of methyl salicylate.

    PubMed

    Fang, Yi; Umasankar, Yogeswaran; Ramasamy, Ramaraja P

    2016-07-15

    An amperometric sensor based on a bi-enzyme modified electrode was fabricated to detect methyl salicylate, a volatile organic compound released by pathogen-infected plants via systemic response. The detection is based on cascadic conversion reactions that result in an amperometric electrochemical signal. The bi-enzyme electrode is made of alcohol oxidase and horseradish peroxidase enzymes immobilized on to a carbon nanotube matrix through a molecular tethering method. Methyl salicylate undergoes hydrolysis to form methanol, which is consumed by alcohol oxidase to form formaldehyde while simultaneously reducing oxygen to hydrogen peroxide. The hydrogen peroxide will be further reduced to water by horseradish peroxidase, which results in an amperometric signal via direct electron transfer. The bi-enzyme biosensor was evaluated by cyclic voltammetry and constant potential amperometry using hydrolyzed methyl salicylate as the analyte. The sensitivity of the bi-enzyme biosensor as determined by cyclic voltammetry and constant potential amperometry were 112.37 and 282.82μAcm(-2)mM(-1) respectively, and the corresponding limits of detection were 22.95 and 0.98μM respectively. Constant potential amperometry was also used to evaluate durability, repeatability and interference from other compounds. Wintergreen oil was used for real sample study to establish the application of the bi-enzyme sensor for selective determination of plant pathogen infections.

  20. Highly selective and sensitive fluorescent sensor: Thiacalix[4]arene-1-naphthalene carboxylate for Zn2+ ions

    NASA Astrophysics Data System (ADS)

    Darjee, Savan M.; Modi, Krunal M.; Panchal, Urvi; Patel, Chirag; Jain, Vinod K.

    2017-04-01

    Thiacalix[4]arene based fluorescent sensor bearing two naphthoyl groups, thiacalix-1-naphthalene carboxylate (TCNC) has been synthesized and characterized by 1H NMR, 13C NMR, FTIR, ESI-MS spectroscopic techniques. The interaction behavior of TCNC with various metal ions like Fe3+, Hg2+, Co2+, Ni2+, Cu2+, Cd2+, Pb2+, Mg2+, K+, Na+, and Zn2+ was studied by UV-visible and emission spectrophotometry. It was observed that TCNC recognizes Zn2+ ions with high selectivity and sensitivity. The enhancement of fluorescence intensity due to presence of Zn2+ ions was not perturbed in the presence of high concentration of other associated metal ions. The 1:1 stoichiometry of TCNC:Zn2+ complex was confirmed by job's plot, ESI-MS study and 1H NMR titration. The binding constant and quantum yield were also calculated by using spectrofluorimetric titration data. Linear detection range of zinc ions was found to be 1 nM-740 nM. Furthermore, molecular docking study was performed to evaluate the binding affinity and possible interactions between TCNC and Zn2+ depicting that TCNC interact with Zn2+ via weak intramolecular forces. In addition to that molecular dynamics has also been performed to evaluate the conformational changes and it's structural stability in the particular environment.

  1. Selection and characterization of a novel photoperiod-sensitive male sterile line in upland cotton.

    PubMed

    Ma, Jianhui; Wei, Hengling; Liu, Ji; Song, Meizhen; Pang, Chaoyou; Wang, Long; Zhang, Wenxiang; Fan, Shuli; Yu, Shuxun

    2013-07-01

    Upland cotton (Gossypium hirsutum L.) shows strong heterosis. However, heterosis is not widely utilized owing to the high cost of hybrid seed production. Creation of a photoperiod-sensitive genetic male sterile line could substantially reduce the cost of hybrid seed production in upland cotton. Such a mutant with virescent marker was found by space mutation in near-earth orbit and its traits had been stable after 4 years of selection in Anyang and Sanya, China. This mutant was fertile with an 11-12.5 h photoperiod when the temperature was higher than 21.5 °C and was sterile with a 13-14.5 h photoperiod. Genetic analysis indicated that both traits were controlled by a single recessive gene or two closely linked genes. Also, the cytological observations and transcriptome profiling analysis showed that the degradation of pollen grain cytoplasm should be the primary reason why the mutant line were male sterile under long-day conditions.

  2. Contaminant tailing in highly heterogeneous porous formations: Sensitivity on model selection and material properties

    NASA Astrophysics Data System (ADS)

    Maghrebi, Mahdi; Jankovic, Igor; Weissmann, Gary S.; Matott, L. Shawn; Allen-King, Richelle M.; Rabideau, Alan J.

    2015-12-01

    Coupled impacts of slow advection, diffusion and sorption were investigated using two heterogeneity models that differ in structure and in the mathematical framework that was used to simulate flow and transport and to quantify contaminant tailing. Both models were built using data from a highly heterogeneous exposure of the Borden Aquifer at a site located 2 km north-west of the Stanford-Waterloo experimental site at Canadian Forces Base Borden, Ontario, Canada. The inclusions-based model used a simplified representation of the different materials found at the site, while the second model was based on transitional probability geostatistics of the formation. These two models were used to investigate sensitivity of contaminant tailing on model selection and on geometric and material properties. While simulations were based on data collected at Borden, models were exercised beyond the geometric and material properties that characterize the site. Various realizations have identified very low conductive silty clay, found at volume fraction of 23.4%, as the material with dominant influence on tailing, and vertical diffusion in and out of low conductive units, affected by sorption, as the dominant transport mechanism causing tailing. The two models yielded almost identical transport results when vertical correlation lengths of silty clay were matched. Several practical implications relevant for characterization of low conductive units were identified and briefly discussed.

  3. Sensitive and Selective Spectrophotometric Determination of Gabapentin in Capsules Using Two Nitrophenols as Chromogenic Agents

    PubMed Central

    Abdulrahman, Sameer A. M.; Basavaiah, Kanakapura

    2011-01-01

    Two simple and selective spectrophotometric methods have been proposed for the determination of gabapentin (GBP) in pure form and in capsules. Both methods are based on the proton transfer from the Lewis acid such as 2,4,6-trinitrophenol (picric acid; PA) or 2,4-dinitrophenol (2,4-DNP) to the primary amino group of GBP which works as Lewis base and formation of yellow ion-pair complexes. The ion-pair complexes formed show absorption maximum at 415 and 420 nm for PA and 2,4-DNP, respectively. Under the optimized experimental conditions, Beer's law is obeyed over the concentration ranges of 1.25–15.0 and 2.0–18.0 μg mL−1 GBP for PA and 2,4-DNP methods, respectively. The molar absorptivity, Sandell's sensitivity, detection and, quantification limits for both methods are also reported. The proposed methods were applied successfully to the determination of GBP in pure form and commercial capsules. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level, and there was no significant difference between the reference and proposed methods with regard to accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition technique. PMID:21760787

  4. A Highly Sensitive and Selective Catalytic Determination of Mercury in Environmental Samples.

    PubMed

    Mohamed, Ashraf A; Ahmed, Nagat A; El-Shahat, Mohamed F

    2016-08-01

    A simple, selective and highly sensitive spectrophotometric method has been developed for mercury determination utilizing its catalytic effect on the isoniazid-hexacyanoferrate (II) reaction. The paper presents for the first time (1) the catalytic effect of Hg (I) on the cited ligand substitution reactions and (2) the activating effect of thiourea on the behavior of mercury. The reaction was monitored spectrophotometrically at 423 nm using the initial rate method. The optimized reaction conditions were 5.0 mmol L(-1) hexacyanoferrate (II), 0.5 mmol L(-1) isoniazid, 150 mmol L(-1) citrate buffer (pH 3.30 ± 0.05), and 0.2 mmol L(-1) thiourea, at 50°C. Linear calibration graphs were obtained for 1-100 and 1-55 µg L(-1) with detection limits, based on the 3Sb-criterion, of 1.2 and 1.8 µg L(-1) of Hg (II) and Hg (I), respectively. The method was conveniently applied to samples of wastewaters, inactivated vaccines, and frozen Bass fish fillet, without any prior separation or preconcentration.

  5. Spinal alpha3beta2* nicotinic acetylcholine receptors tonically inhibit the transmission of nociceptive mechanical stimuli.

    PubMed

    Young, Tracey; Wittenauer, Shannon; McIntosh, J Michael; Vincler, Michelle

    2008-09-10

    The presence of non-alpha4beta2, non-alpha7 nicotinic acetylcholine receptors (nAChR) in the rat spinal cord has been suggested previously, but the identity of these nAChRs had not been shown. Intrathecal administration of the alpha3beta2*/alpha6beta2* selective alpha-conotoxin MII (alpha-CTX MII) dose- and time-dependently reduced paw withdrawal thresholds to mechanical pressure in normal rats. The pronociceptive effect of alpha-CTX MII was partially blocked by NMDA receptor antagonism and lost completely following ablation of C-fibers. The effect of spinal nerve ligation on alpha-CTX MII-induced mechanical hypersensitivity was also assessed. Sensitivity was lost in the hind paw ipsilateral to spinal nerve ligation, but maintained in the contralateral hind paw at control levels. Radioligand binding in spinal cord membranes revealed high and low affinity alpha-CTX MII binding sites. Spinal nerve ligation did not significantly alter alpha-CTX MII binding ipsilateral to ligation. Finally, no evidence for the presence of alpha6-containing nAChRs was identified. The results of these studies show the presence of 2 populations of alpha-CTX MII-sensitive nAChRs containing the alpha3 and beta2, but not the alpha6, subunits in the rat spinal cord that function to inhibit the transmission of nociceptive mechanical stimuli via inhibiting the release of glutamate from C-fibers. Spinal nerve ligation produces a unilateral loss of alpha-CTX MII-induced mechanical hypersensitivity without altering alpha-CTX MII binding sites. Our data support a peripheral injury-induced loss of a cholinergic inhibitory tone at spinal alpha3beta2* nAChRs, without the loss of the receptors themselves, which may contribute to mechanical hypersensitivity following spinal nerve ligation.

  6. Highly sensitive and selective lateral flow immunoassay based on magnetic nanoparticles for quantitative detection of carcinoembryonic antigen.

    PubMed

    Liu, Fangming; Zhang, Honglian; Wu, Zhenhua; Dong, Haidao; Zhou, Lin; Yang, Dawei; Ge, Yuqing; Jia, Chunping; Liu, Huiying; Jin, Qinghui; Zhao, Jianlong; Zhang, Qiqing; Mao, Hongju

    2016-12-01

    Carcinoembryonic antigen (CEA) is an important biomarker in cancer diagnosis. Here, we present an efficient, selective lateral-flow immunoassay (LFIA) based on magnetic nanoparticles (MNPs) for in situ sensitive and accurate point-of-care detection of CEA. Signal amplification mechanism involved linking of detection MNPs with signal MNPs through biotin-modified single-stranded DNA (ssDNA) and streptavidin. To verify the effectiveness of this modified LFIA system, the sensitivity and specificity were evaluated. Sensitivity evaluation showed a broad detection range of 0.25-1000ng/ml for CEA protein by the modified LFIA, and the limit of detection (LOD) of the modified LFIA was 0.25ng/ml, thus producing significant increase in detection threshold compared with the traditional LFIA. The modified LFIA could selectively recognize CEA in presence of several interfering proteins. In addition, this newly developed assay was applied for quantitative detection of CEA in human serum specimens collected from 10 randomly selected patients. The modified LFIA system detected minimum 0.27ng/ml of CEA concentration in serum samples. The results were consistent with the clinical data obtained using commercial electrochemiluminescence immunoassay (ECLIA) (p<0.01). In conclusion, the MNPs based LFIA system not only demonstrated enhanced signal to noise ratio, it also detected CEA with higher sensitivity and selectivity, and thus has great potential to be commercially applied as a sensitive tumor marker filtration system.

  7. Increasing the selectivity and sensitivity of gas sensors for the detection of explosives

    NASA Astrophysics Data System (ADS)

    Mallin, Daniel

    Over the past decade, the use of improvised explosive devices (IEDs) has increased, domestically and internationally, highlighting a growing need for a method to quickly and reliably detect explosive devices in both military and civilian environments before the explosive can cause damage. Conventional techniques have been successful in explosive detection, however they typically suffer from enormous costs in capital equipment and maintenance, costs in energy consumption, sampling, operational related expenses, and lack of continuous and real-time monitoring. The goal was thus to produce an inexpensive, portable sensor that continuously monitors the environment, quickly detects the presence of explosive compounds and alerts the user. In 2012, here at URI, a sensor design was proposed for the detection of triacetone triperoxide (TATP). The design entailed a thermodynamic gas sensor that measures the heat of decomposition between trace TATP vapor and a metal oxide catalyst film. The sensor was able to detect TATP vapor at the part per million level (ppm) and showed great promise for eventual commercial use, however, the sensor lacked selectivity. Thus, the specific objective of this work was to take the original sensor design proposed in 2012 and to make several key improvements to advance the sensor towards commercialization. It was demonstrated that a sensor can be engineered to detect TATP and ignore the effects of interferent H2O2 molecules by doping SnO2 films with varying amounts of Pd. Compared with a pure SnO2 catalyst, a SnO2, film doped with 8 wt. % Pd had the highest selectivity between TATP and H2O2. Also, at 12 wt. % Pd, the response to TATP and H2O2 was enhanced, indicating that sensitivity, not only selectivity, can be increased by modifying the composition of the catalyst. An orthogonal detection system was demonstrated. The platform consists of two independent sensing mechanisms, one thermodynamic and one conductometric, which take measurements from

  8. A Sensitivity Study of Liric Algorithm to User-defined Input Parameters, Using Selected Cases from Thessaloniki's Measurements

    NASA Astrophysics Data System (ADS)

    Filioglou, M.; Balis, D.; Siomos, N.; Poupkou, A.; Dimopoulos, S.; Chaikovsky, A.

    2016-06-01

    A targeted sensitivity study of the LIRIC algorithm was considered necessary to estimate the uncertainty introduced to the volume concentration profiles, due to the arbitrary selection of user-defined input parameters. For this purpose three different tests were performed using Thessaloniki's Lidar data. Overall, tests in the selection of the regularization parameters, an upper and a lower limit test were performed. The different sensitivity tests were applied on two cases with different predominant aerosol types, a dust episode and a typical urban case.

  9. Rapid and sensitive lateral flow immunoassay method for determining alpha fetoprotein in serum using europium (III) chelate microparticles-based lateral flow test strips.

    PubMed

    Liang, Rong-Liang; Xu, Xu-Ping; Liu, Tian-Cai; Zhou, Jian-Wei; Wang, Xian-Guo; Ren, Zhi-Qi; Hao, Fen; Wu, Ying-Song

    2015-09-03

    Alpha-fetoprotein (AFP), a primary marker for many diseases including various cancers, is important in clinical tumor diagnosis and antenatal screening. Most immunoassays provide high sensitivity and accuracy for determining AFP, but they are expensive, often complex, time-consuming procedures. A simple and rapid point-of-care system that integrates Eu (III) chelate microparticles with lateral flow immunoassay (LFIA) has been developed to determine AFP in serum with an assay time of 15 min. The approach is based on a sandwich immunoassay performed on lateral flow test strips. A fluorescence strip reader was used to measure the fluorescence peak heights of the test line (HT) and the control line (HC); the HT/HC ratio was used for quantitation. The Eu (III) chelate microparticles-based LFIA assay exhibited a wide linear range (1.0-1000 IU mL(-1)) for AFP with a low limit of detection (0.1 IU mL(-1)) based on 5ul of serum. Satisfactory specificity and accuracy were demonstrated and the intra- and inter-assay coefficients of variation (CV) for AFP were both <10%. Furthermore, in the analysis of human serum samples, excellent correlation (n = 284, r = 0.9860, p < 0.0001) was obtained between the proposed method and a commercially available CLIA kit. Results indicated that the Eu (III) chelate microparticles-based LFIA system provided a rapid, sensitive and reliable method for determining AFP in serum, indicating that it would be suitable for development in point-of-care testing.

  10. Metabolites related to gut bacterial metabolism, peroxisome proliferator-activated receptor-alpha activation, and insulin sensitivity are associated with physical function in functionally-limited older adults

    PubMed Central

    Lustgarten, Michael S; Price, Lori L; Chalé, Angela; Fielding, Roger A

    2014-01-01

    Identification of mechanisms underlying physical function will be important for addressing the growing challenge that health care will face with physical disablement in the expanding aging population. Therefore, the goals of the current study were to use metabolic profiling to provide insight into biologic mechanisms that may underlie physical function by examining the association between baseline and the 6-month change in serum mass spectrometry-obtained amino acids, fatty acids, and acylcarnitines with baseline and the 6-month change in muscle strength (leg press one repetition maximum divided by total lean mass, LP/Lean), lower extremity function [short physical performance battery (SPPB)], and mobility (400 m gait speed, 400-m), in response to 6 months of a combined resistance exercise and nutritional supplementation (whey protein or placebo) intervention in functionally-limited older adults (SPPB ≤ 10; 70–85 years, N = 73). Metabolites related to gut bacterial metabolism (cinnamoylglycine, phenol sulfate, p-cresol sulfate, 3-indoxyl sulfate, serotonin, N-methylproline, hydrocinnamate, dimethylglycine, trans-urocanate, valerate) that are altered in response to peroxisome proliferator-activated receptor-alpha (PPAR-α) activation (α-hydroxyisocaproate, α-hydroxyisovalerate, 2-hydroxy-3-methylvalerate, indolelactate, serotonin, 2-hydroxypalmitate, glutarylcarnitine, isobutyrylcarnitine, cinnamoylglycine) and that are related to insulin sensitivity (monounsaturated fatty acids: 5-dodecenoate, myristoleate, palmitoleate; γ-glutamylamino acids: γ-glutamylglutamine, γ-glutamylalanine, γ-glutamylmethionine, γ-glutamyltyrosine; branched-chain amino acids: leucine, isoleucine, valine) were associated with function at baseline, with the 6-month change in function or were identified in backward elimination regression predictive models. Collectively, these data suggest that gut microbial metabolism, PPAR-α activation, and insulin sensitivity may be involved in

  11. In silico selection of an aptamer to estrogen receptor alpha using computational docking employing estrogen response elements as aptamer-alike molecules

    PubMed Central

    Ahirwar, Rajesh; Nahar, Smita; Aggarwal, Shikha; Ramachandran, Srinivasan; Maiti, Souvik; Nahar, Pradip

    2016-01-01

    Aptamers, the chemical-antibody substitute to conventional antibodies, are primarily discovered through SELEX technology involving multi-round selections and enrichment. Circumventing conventional methodology, here we report an in silico selection of aptamers to estrogen receptor alpha (ERα) using RNA analogs of human estrogen response elements (EREs). The inverted repeat nature of ERE and the ability to form stable hairpins were used as criteria to obtain aptamer-alike sequences. Near-native RNA analogs of selected single stranded EREs were modelled and their likelihood to emerge as ERα aptamer was examined using AutoDock Vina, HADDOCK and PatchDock docking. These in silico predictions were validated by measuring the thermodynamic parameters of ERα -RNA interactions using isothermal titration calorimetry. Based on the in silico and in vitro results, we selected a candidate RNA (ERaptR4; 5′-GGGGUCAAGGUGACCCC-3′) having a binding constant (Ka) of 1.02 ± 0.1 × 108 M−1 as an ERα-aptamer. Target-specificity of the selected ERaptR4 aptamer was confirmed through cytochemistry and solid-phase immunoassays. Furthermore, stability analyses identified ERaptR4 resistant to serum and RNase A degradation in presence of ERα. Taken together, an efficient ERα-RNA aptamer is identified using a non-SELEX procedure of aptamer selection. The high-affinity and specificity can be utilized in detection of ERα in breast cancer and related diseases. PMID:26899418

  12. Genetic disruption of the On visual pathway affects cortical orientation selectivity and contrast sensitivity in mice

    PubMed Central

    Sarnaik, Rashmi; Chen, Hui; Liu, Xiaorong

    2014-01-01

    The retina signals stimulus contrast via parallel On and Off pathways and sends the information to higher visual centers. Here we study the role of the On pathway using mice that have null mutations in the On-specific GRM6 receptor in the retina (Pinto LH, Vitaterna MH, Shimomura K, Siepka SM, Balannik V, McDearmon EL, Omura C, Lumayag S, Invergo BM, Brandon M, Glawe B, Cantrell DR, Donald R, Inayat S, Olvera MA, Vessey KA, Kirstan A, McCall MA, Maddox D, Morgans CW, Young B, Pletcher MT, Mullins RF, Troy JB, Takahashi JS. Vis Neurosci 24: 111–123, 2007; Maddox DM, Vessey KA, Yarbrough GL, Invergo BM, Cantrell DR, Inayat S, Balannik V, Hicks WL, Hawes NL, Byers S, Smith RS, Hurd R, Howell D, Gregg RG, Chang B, Naggert JK, Troy JB, Pinto LH, Nishina PM, McCall MA. J Physiol 586: 4409–4424, 2008). In these “nob” mice, single unit recordings in the primary visual cortex (V1) reveal degraded selectivity for orientations due to an increased response at nonpreferred orientations. Contrast sensitivity in the nob mice is reduced with severe deficits at low contrast, consistent with the phenotype of night blindness in human patients with mutations in Grm6. These cortical deficits can be largely explained by reduced input drive and increased response variability seen in nob V1. Interestingly, increased variability is also observed in the superior colliculus of these mice but does not affect its tuning properties. Further, the increased response variability in the nob mice is traced to the retina, a result phenocopied by acute pharmacological blockade of the On pathway in wild-type retina. Together, our results suggest that the On and Off pathways normally interact to increase response reliability in the retina, which in turn propagates to various central visual targets and affects their functional properties. PMID:24598523

  13. Using Impact-Relevant Sensitivities to Efficiently Evaluate and Select Climate Change Scenarios

    NASA Astrophysics Data System (ADS)

    Vano, J. A.; Kim, J. B.; Rupp, D. E.; Mote, P.

    2014-12-01

    We outline an efficient approach to help researchers and natural resource managers more effectively use global climate model information in their long-term planning. The approach provides an estimate of the magnitude of change of a particular impact (e.g., summertime streamflow) from a large ensemble of climate change projections prior to detailed analysis. These estimates provide both qualitative information as an end unto itself (e.g., the distribution of future changes between emissions scenarios for the specific impact) and a judicious, defensible evaluation structure that can be used to qualitatively select a sub-set of climate models for further analysis. More specifically, the evaluation identifies global climate model scenarios that both (1) span the range of possible futures for the variable/s most important to the impact under investigation, and (2) come from global climate models that adequately simulate historical climate, providing plausible results for the future climate in the region of interest. To identify how an ecosystem process responds to projected future changes, we methodically sample, using a simple sensitivity analysis, how an impact variable (e.g., streamflow magnitude, vegetation carbon) responds locally to projected regional temperature and precipitation changes. We demonstrate our technique over the Pacific Northwest, focusing on two types of impacts each in three distinct geographic settings: (a) changes in streamflow magnitudes in critical seasons for water management in the Willamette, Yakima, and Upper Columbia River basins; and (b) changes in annual vegetation carbon in the Oregon and Washington Coast Ranges, Western Cascades, and Columbia Basin ecoregions.

  14. Selective inhibition of 14 alpha-desmethyl sterol synthesis in Candida albicans by terconazole, a new triazole antimycotic.

    PubMed

    Isaacson, D M; Tolman, E L; Tobia, A J; Rosenthale, M E; McGuire, J L; Vanden Bossche, H; Janssen, P A

    1988-03-01

    Terconazole, a new broad spectrum antimycotic triazole derivative, has been shown to have potent activity against Candida albicans in vitro and to be effective in animal models of yeast infections. The present study explored a possible mechanism of anticandidal activity of terconazole. The compound inhibited production of 14 alpha-desmethyl sterols (e.g. ergosterol) in C. albicans at concentrations (IC50 = 3-6 x 10(-9) M) lower than those inhibiting the in-vitro growth of the yeast. There was concomitant accumulation of methylated sterols, (e.g. lanosterol), which are considered detrimental to normal yeast cell membrane function. Terconazole stimulated incorporation of 14C-acetate into triglycerides, but had no other effect on C. albicans lipid metabolism. At concentrations greater than or equal to 10(-6)M terconazole inhibited the oxidation of 14C-acetate into 14CO2 in C. albicans although the mechanism for this effect remains unclear. These data indicate that terconazole is a specific inhibitor of yeast C-14 desmethyl sterol production in C. albicans. Furthermore, terconazole reduced cytochrome P-450 levels in yeast microsomes at concentrations 10,000-fold below those at which it showed effects on rabbit liver microsomes. These data indicate a species specificity for the biochemical actions of terconazole. The C-14 alpha-desmethylase system in yeast cell membranes is cytochrome P-450 associated. Thus, terconazole, was a potent inhibitor of C-14 desmethyl sterol synthesis. This effect could contribute to the anticandidal activity of the drug.

  15. Selectivity guidelines and a reductive elimination-based model for predicting the stereochemical course of conjugate addition reactions of organocuprates to gamma-alkoxy-alpha,beta-enoates.

    PubMed

    Kireev, Artem S; Manpadi, Madhuri; Kornienko, Alexander

    2006-03-31

    Current models used to predict the stereochemical outcome of organocopper conjugate addition processes focus on the nucleophilic addition step as stereochemistry-determining. Recent kinetic, NMR, kinetic isotope effect, and theoretical density functional studies strongly support the proposal that stereochemical preferences in these processes are dictated by the reductive elimination step, transforming Cu(III) to Cu(I) intermediates. A new model that considers various steric and stereoelectronic factors involved in the transition state of the reductive elimination step is proposed and then used to interpret the results of systematic studies of arylcuprate conjugate addition reactions with cis and trans gamma-alkoxy-alpha,beta-enoates. The results give rise to the following selectivity guidelines for this process. To achieve high anti-addition diastereoselectivities the use of trans esters with a bulky nonalkoxy substituent at the gamma-position is recommended. While stereoelectronics disfavor syn-addition, a judicious choice of properly sized gamma-substituents may lead to the predominant formation of syn-products, especially with cis enoates. However, high syn-selectivities may be achieved by using gamma-amino-alpha,beta-enoates.

  16. 21-(/sup 18/F)fluoro-16 alpha-ethyl-19-norprogesterone: synthesis and target tissue selective uptake of a progestin receptor based radiotracer for positron emission tomography

    SciTech Connect

    Pomper, M.G.; Katzenellenbogen, J.A.; Welch, M.J.; Brodack, J.W.; Mathias, C.J.

    1988-07-01

    We have synthesized 21-(/sup 18/F)fluoro-16 alpha-ethyl-19-norprogesterone (FENP), a high affinity ligand for the progesterone receptor, labeled with the positron-emitting radionuclide fluorine-18 (t1/2 = 110 min). The synthesis proceeds in two steps from 21-hydroxy-16 alpha-ethyl-19-norprogesterone and involves (/sup 18/F)fluoride ion displacement of the 21-trifluoromethanesulfonate (21-triflate). This material is purified by HPLC and is obtained in 4-30% overall yield (decay corrected) within 40 min after the end of bombardment to produce (/sup 18/F)fluoride ion. The effective specific activity, determined by competitive radioreceptor binding assays, is 700-1400 Ci/mmol. In vivo, (/sup 18/F)FENP demonstrates highly selective, receptor-mediated uptake by the uterus of estrogen-primed rats; the uterus to blood and uterus to muscle ratios were respectively 26 and 16 at 1 h and 71 and 41 at 3 h after injection. The high target tissue selectivity of this uptake suggests that this compound may be useful for the in vivo imaging of progestin target tissues and receptor-rich tumors (such as human breast tumors) by positron emission tomography.

  17. Non-sensitized selective photochemical reduction of CO2 to CO under visible light with an iron molecular catalyst.

    PubMed

    Rao, Heng; Bonin, Julien; Robert, Marc

    2017-03-02

    A substituted tetraphenyl iron porphyrin, bearing positively charged trimethylammonio groups at the para position of each phenyl ring, demonstrates its ability as a homogeneous molecular catalyst to selectively reduce CO2 to CO under visible light irradiation in organic media without the assistance of a sensitizer and no competitive hydrogen evolution for several days.

  18. A ferrofluid-based homogeneous assay for highly sensitive and selective detection of single-nucleotide polymorphisms.

    PubMed

    Shen, Wei; Lim, Cai Le; Gao, Zhiqiang

    2013-09-21

    A simple and low-cost colorimetric assay utilizing ferrofluidic nanoparticulate probes (FNPs) and a ligase for single-nucleotide polymorphism genotyping is described. Excellent sensitivity and selectivity were accomplished through the engagement of the FNPs and a ligase chain reaction.

  19. Boronic Acid: A Bio-Inspired Strategy To Increase the Sensitivity and Selectivity of Fluorescent NADH Probe.

    PubMed

    Wang, Lu; Zhang, Jingye; Kim, Beomsue; Peng, Juanjuan; Berry, Stuart N; Ni, Yong; Su, Dongdong; Lee, Jungyeol; Yuan, Lin; Chang, Young-Tae

    2016-08-24

    Fluorescent probes have emerged as an essential tool in the molecular recognition events in biological systems; however, due to the complex structures of certain biomolecules, it remains a challenge to design small-molecule fluorescent probes with high sensitivity and selectivity. Inspired by the enzyme-catalyzed reaction between biomolecule and probe, we present a novel combination-reaction two-step sensing strategy to improve sensitivity and selectivity. Based on this strategy, we successfully prepared a turn-on fluorescent reduced nicotinamide adenine dinucleotide (NADH) probe, in which boronic acid was introduced to bind with NADH and subsequently accelerate the sensing process. This probe shows remarkably improved sensitivity (detection limit: 0.084 μM) and selectivity to NADH in the absence of any enzymes. In order to improve the practicality, the boronic acid was further modified to change the measurement conditions from alkalescent (pH 9.5) to physiological environment (pH 7.4). Utilizing these probes, we not only accurately quantified the NADH weight in a health care product but also evaluated intracellular NADH levels in live cell imaging. Thus, these bio-inspired fluorescent probes offer excellent tools for elucidating the roles of NADH in biological systems as well as a practical strategy to develop future sensitive and selective probes for complicated biomolecules.

  20. STAR FORMATION RATES AND STELLAR MASSES OF H{alpha} SELECTED STAR-FORMING GALAXIES AT z = 0.84: A QUANTIFICATION OF THE DOWNSIZING

    SciTech Connect

    Villar, Victor; Gallego, Jesus; Perez-Gonzalez, Pablo G.; Barro, Guillermo; Zamorano, Jaime; Noeske, Kai; Koo, David C. E-mail: j.gallego@fis.ucm.es E-mail: gbarro@fis.ucm.es E-mail: noeske@stsci.edu

    2011-10-10

    In this work we analyze the physical properties of a sample of 153 star-forming galaxies at z {approx} 0.84, selected by their H{alpha} flux with a narrowband filter. B-band luminosities of the objects are higher than those of local star-forming galaxies. Most of the galaxies are located in the blue cloud, though some objects are detected in the green valley and in the red sequence. After the extinction correction is applied, virtually all these red galaxies move to the blue sequence, unveiling their dusty nature. A check on the extinction law reveals that the typical extinction law for local starbursts is well suited for our sample but with E(B - V){sub stars} = 0.55 E(B - V){sub gas}. We compare star formation rates (SFRs) measured with different tracers (H{alpha}, far-ultraviolet, and infrared), finding that they agree within a factor of three after extinction correction. We find a correlation between the ratios SFR{sub FUV}/SFR{sub H{alpha}}, SFR{sub IR}/SFR{sub H{alpha}}, and the EW(H{alpha}) (i.e., weighted age), which accounts for part of the scatter. We obtain stellar mass estimations by fitting templates to multi-wavelength photometry. The typical stellar mass of a galaxy within our sample is {approx}10{sup 10} M{sub sun}. The SFR is correlated with stellar mass and the specific SFR decreases with it, indicating that massive galaxies are less affected by star formation processes than less massive ones. This result is consistent with the downsizing scenario. To quantify this downsizing we estimated the quenching mass M{sub Q} for our sample at z {approx} 0.84, finding that it declines from M{sub Q} {approx} 10{sup 12} M{sub sun} at z {approx} 0.84 to M{sub Q} {approx} 8 x 10{sup 10} M{sub sun} at the local universe.

  1. Toxicity, localization and elimination of the phototoxin, alpha-terthienyl, in mosquito larvae.

    PubMed

    Hasspieler, B M; Arnason, J T; Downe, A E

    1988-12-01

    Mosquito larvae were examined to determine interspecific and interstrain differences in susceptibility to the larvicidal effects of the plant-derived phototoxin, alpha-terthienyl (alpha-T). The LC50 values were as follows: Aedes aegypti, 4 ppb; Ae. epactius, 6 ppb; anopheles stephensi, 14 ppb; malathion-susceptible Culex tarsalis (S), 12 ppb; malathion-resistant Cx. tarsalis (R), 16 ppb. Fluorescence studies indicated localization of alpha-T in the midgut epithelium and in the lumen of Malpighian tubules. Rates of elimination of tritiated alpha-T differed significantly between Ae. aegypti and Cx. tarsalis (S) larvae. Rate of 3H-alpha-T elimination was inversely correlated with susceptibility to the toxic effects of the compound. The toxicological significance of selective alpha-T accumulation and the importance of alpha-T elimination in determining sensitivity are discussed.

  2. (-)-Spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin-2'-one], a conformationally restricted analogue of acetylcholine, is a highly selective full agonist at the alpha 7 nicotinic acetylcholine receptor.

    PubMed

    Mullen, G; Napier, J; Balestra, M; DeCory, T; Hale, G; Macor, J; Mack, R; Loch, J; Wu, E; Kover, A; Verhoest, P; Sampognaro, A; Phillips, E; Zhu, Y; Murray, R; Griffith, R; Blosser, J; Gurley, D; Machulskis, A; Zongrone, J; Rosen, A; Gordon, J

    2000-11-02

    Neuronal nicotinic acetylcholine receptors are members of the ligand-gated ion channel receptor superfamily and may play important roles in modulating neurotransmission, cognition, sensory gating, and anxiety. Because of its distribution and abundance in the CNS, the alpha 7 nicotinic receptor is a strong candidate to be involved in some of these functions. In this paper we describe the synthesis and in vitro profile of AR-R17779, (-)-spiro[1-azabicyclo[2.2. 2]octane-3,5'-oxazolidin-2'-one] (4a), a potent full agonist at the rat alpha 7 nicotinic receptor, which is highly selective for the rat alpha 7 nicotinic receptor over the alpha 4 beta 2 subtype. Preliminary SAR of AR-R17779 presented here indicate that there is little scope for modification of this rigid molecule as even minor changes result in significant loss of the alpha 7 nicotinic receptor affinity.

  3. Beta-Adrenergic Receptor 1 Selective Antagonism Inhibits Norepinephrine-Mediated TNF-Alpha Downregulation in Experimental Liver Cirrhosis

    PubMed Central

    Zapater, Pedro; Gómez-Hurtado, Isabel; Peiró, Gloria; González-Navajas, José Manuel; García, Irma; Giménez, Paula; Moratalla, Alba; Such, José; Francés, Rubén

    2012-01-01

    Background Bacterial translocation is a frequent event in cirrhosis leading to an increased inflammatory response. Splanchnic adrenergic system hyperactivation has been related with increased bacterial translocation. We aim at evaluating the interacting mechanism between hepatic norepinephrine and inflammation during liver damage in the presence of bacterial-DNA. Animals and Methods Forty-six mice were included in a 16-week protocol of CCl4-induced cirrhosis. Laparotomies were performed at weeks 6, 10, 13 and 16. A second set of forty mice injected with a single intraperitoneal dose of CCl4 was treated with saline, 6-hydroxidopamine, Nebivolol or Butoxamine. After 5 days, mice received E. coli-DNA intraperitoneally. Laparotomies were performed 24 hours later. Liver bacterial-DNA, norepinephrine, TNF-alpha, IL-6 and beta-adrenergic receptor levels were measured. Results Bacterial-DNA translocation was more frequent in CCl4-treated animals compared with controls, and increased as fibrosis progressed. Liver norepinephrine and pro-inflammatory cytokines were significantly higher in mice with vs without bacterial-DNA (319.7±120.6 vs 120.7±68.6 pg/g for norepinephrine, 38.4±6.1 vs 29.7±4.2 pg/g for TNF-alpha, 41.8±7.4 vs 28.7±4.3 pg/g for IL-6). Only beta-adrenergic receptor-1 was significantly increased in treated vs control animals (34.6±7.3 vs 12.5±5.3, p = 0.01) and correlated with TNF-alpha, IL-6 and norepinephrine hepatic levels in animals with bacterial-DNA. In the second set of mice, cytokine levels were increased in 6-hydroxidopamine and Nebivolol (beta-adrenergic receptor-1 antagonist) treated mice compared with saline. Butoxamine (beta-adrenergic receptor-2 antagonist) didn’t inhibit liver norepinephrine modulation of pro-inflammatory cytokines. Conclusions Beta-adrenergic receptor-1 mediates liver norepinephrine modulation of the pro-inflammatory response in CCl4-treated mice with bacterial-DNA. PMID:22916250

  4. Highly selective and sensitive detection of neurotransmitters using receptor-modified single-walled carbon nanotube sensors

    NASA Astrophysics Data System (ADS)

    Kim, Byeongju; Song, Hyun Seok; Jin, Hye Jun; Park, Eun Jin; Lee, Sang Hun; Lee, Byung Yang; Park, Tai Hyun; Hong, Seunghun

    2013-07-01

    We present receptor-modified carbon nanotube sensors for the highly selective and sensitive detection of acetylcholine (ACh), one kind of neurotransmitter. Here, we successfully expressed the M1 muscarinic acetylcholine receptor (M1 mAChR), a family of G protein-coupled receptors (GPCRs), in E. coli and coated single-walled carbon nanotube (swCNT)-field effect transistors (FETs) with lipid membrane including the receptor, enabling highly selective and sensitive ACh detection. Using this sensor, we could detect ACh at 100 pM concentration. Moreover, we showed that this sensor could selectively detect ACh among other neurotransmitters. This is the first demonstration of the real-time detection of ACh using specific binding between ACh and M1 mAChR, and it may lead to breakthroughs for various applications such as disease diagnosis and drug screening.

  5. The sensitizing capacity of Alstroemeria cultivars in man and guinea pig. Remarks on the occurrence, quantity and irritant and sensitizing potency of their constituents tuliposide A and tulipalin A (alpha-methylene-gamma-butyrolactone).

    PubMed

    Hausen, B M; Prater, E; Schubert, H

    1983-01-01

    Dermatitis in 8 female nursery workers handling Alstroemeria ligtu cultivars has been proven/proved in 6 cases to be of allergic origin. Epicutaneous tests with cut flower extracts as well as with the isolated and purified sensitizer were positive. Successful animal experiments corroborated the sensitising capacity of Alstroemeria cultivars. The responsible but unstable contact allergen, alpha-methylene-gamma-butyrolactone (tulipalin A), was found in short ether extracts of flower petals in concentrations up to 18%. Due to its instability, subsequent extractions were performed with methanol, yielding the sensitising constituent after purification in the glucosidic form (tuliposide A). This could be stored at room temperature for longer periods without loss of activity. Tuliposide A was determined in specimens of Alstroemeria ligtu cultivars of 14 different origins of various colours; its content varied between 1 and 2%. Direct testing of the plant material in human patients carries the risk of false positive reactions and active sensitisation, as the threshold for both forms of the allergen is very high. Only a concentration of 0.01% can be considered safe.

  6. Effect of gelatinization and hydrolysis conditions on the selectivity of starch hydrolysis with alpha-amylase from Bacillus licheniformis.

    PubMed

    Baks, Tim; Bruins, Marieke E; Matser, Ariette M; Janssen, Anja E M; Boom, Remko M

    2008-01-23

    Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on the hydrolyzate composition and reaction rate during wheat starch hydrolysis with alpha-amylase from Bacillus licheniformis were compared. Suspensions of native starch or starch gelatinized at different conditions either with or without enzyme were hydrolyzed. During hydrolysis, the oligosaccharide concentration, the dextrose equivalent, and the enzyme activity were determined. We found that the hydrolyzate composition was affected by the type of starch pretreatment and the enzyme addition point but that it was just minimally affected by the pressure applied during hydrolysis, as long as gelatinization was complete. The differences between hydrolysis of thermally gelatinized, high-pressure gelatinized, and native starch were explained by considering the granule structure and the specific surface area of the granules. These results show that the hydrolyzate composition can be influenced by choosing different process sequences and conditions.

  7. Effect of Alpha-Hederin, the active constituent of Nigella sativa, on miRNA-126, IL-13 mRNA levels and inflammation of lungs in ovalbumin-sensitized male rats

    PubMed Central

    Fallahi, Maryam; Keyhanmanesh, Rana; Khamaneh, Amir Mahdi; Ebrahimi Saadatlou, Mohammad Ali; Saadat, Saeideh; Ebrahimi, Hadi

    2016-01-01

    Objective: In previous studies the therapeutic effects of Nigella sativa have been demonstrated on asthmatic animals. In the present study, the preventive effect of single dose of alpha-hederin, its active constituent, has been evaluated on lung inflammation and some inflammatory mediators in lungs of ovalbumin sensitized rat in order to elicit its mechanism. Materials and Methods: Forty rats were randomly grouped in 4 groups; control (C), sensitized (S), sensitized pretreated groups with thymoquinone (3 mg/kg i.p., S+TQ) and alpha-hederin (0.02 mg/kg i.p., S+AH). Levels of IL-13 mRNA and miRNA-126 in lung tissue and its pathological changes in each group were assessed. Results: Elevated levels of miRNA-126, IL-13 mRNA and pathological changes were observed in the sensitized group compared to the control group (p<0.001 to p<0.05). All of these factors were significantly reduced in S+TQ and S+AH groups in comparison to S group (p<0.001 to p<0.05). Although alpha-hederin decreased the levels of miRNA-126, IL-13 mRNA and pathological changes in comparison with thymoquinone, the results were statistically not significant. Conclusion: The results suggested that alpha-hederin had preventive effect on sensitized rats like thymoquinone. It may intervene in miRNA-126 expression, which consequently could interfere with IL-13 secretion pathway leading to a reduction in inflammatory responses. PMID:27247924

  8. Nitric oxide enhances the sensitivity of alpaca melanocytes to respond to {alpha}-melanocyte-stimulating hormone by up-regulating melanocortin-1 receptor

    SciTech Connect

    Dong, Yanjun; Cao, Jing; Wang, Haidong; Zhang, Jie; Zhu, Zhiwei; Bai, Rui; Hao, HuanQing; He, Xiaoyan; Fan, Ruiwen; Dong, Changsheng

    2010-06-11

    Nitric oxide (NO) and {alpha}-melanocyte-stimulating hormone ({alpha}-MSH) have been correlated with the synthesis of melanin. The NO-dependent signaling of cellular response to activate the hypothalamopituitary proopiomelanocortin system, thereby enhances the hypophysial secretion of {alpha}-MSH to stimulate {alpha}-MSH-receptor responsive cells. In this study we investigated whether an NO-induced pathway can enhance the ability of the melanocyte to respond to {alpha}-MSH on melanogenesis in alpaca skin melanocytes in vitro. It is important for us to know how to enhance the coat color of alpaca. We set up three groups for experiments using the third passage number of alpaca melanocytes: the control cultures were allowed a total of 5 days growth; the UV group cultures like the control group but the melanocytes were then irradiated everyday (once) with 312 mJ/cm{sup 2} of UVB; the UV + L-NAME group is the same as group UV but has the addition of 300 {mu}M L-NAME (every 6 h). To determine the inhibited effect of NO produce, NO produces were measured. To determine the effect of the NO to the key protein and gene of {alpha}-MSH pathway on melanogenesis, the key gene and protein of the {alpha}-MSH pathway were measured by quantitative real-time PCR and Western immunoblotting. The results provide exciting new evidence that NO can enhance {alpha}-MSH pathway in alpaca skin melanocytes by elevated MC1R. And we suggest that the NO pathway may more rapidly cause the synthesis of melanin in alpaca skin under UV, which at that time elevates the expression of MC1R and stimulates the keratinocytes to secrete {alpha}-MSH to enhance the {alpha}-MSH pathway on melanogenesis. This process will be of considerable interest in future studies.

  9. Nitric oxide enhances the sensitivity of alpaca melanocytes to respond to alpha-melanocyte-stimulating hormone by up-regulating melanocortin-1 receptor.

    PubMed

    Dong, Yanjun; Cao, Jing; Wang, Haidong; Zhang, Jie; Zhu, Zhiwei; Bai, Rui; Hao, HuanQing; He, Xiaoyan; Fan, Ruiwen; Dong, Changsheng

    2010-06-11

    Nitric oxide (NO) and alpha-melanocyte-stimulating hormone (alpha-MSH) have been correlated with the synthesis of melanin. The NO-dependent signaling of cellular response to activate the hypothalamopituitary proopiomelanocortin system, thereby enhances the hypophysial secretion of alpha-MSH to stimulate alpha-MSH-receptor responsive cells. In this study we investigated whether an NO-induced pathway can enhance the ability of the melanocyte to respond to alpha-MSH on melanogenesis in alpaca skin melanocytes in vitro. It is important for us to know how to enhance the coat color of alpaca. We set up three groups for experiments using the third passage number of alpaca melanocytes: the control cultures were allowed a total of 5 days growth; the UV group cultures like the control group but the melanocytes were then irradiated everyday (once) with 312 mJ/cm(2) of UVB; the UV+L-NAME group is the same as group UV but has the addition of 300 microM L-NAME (every 6h). To determine the inhibited effect of NO produce, NO produces were measured. To determine the effect of the NO to the key protein and gene of alpha-MSH pathway on melanogenesis, the key gene and protein of the alpha-MSH pathway were measured by quantitative real-time PCR and Western immunoblotting. The results provide exciting new evidence that NO can enhance alpha-MSH pathway in alpaca skin melanocytes by elevated MC1R. And we suggest that the NO pathway may more rapidly cause the synthesis of melanin in alpaca skin under UV, which at that time elevates the expression of MC1R and stimulates the keratinocytes to secrete alpha-MSH to enhance the alpha-MSH pathway on melanogenesis. This process will be of considerable interest in future studies.

  10. Sublethal exposure to alpha radiation (223Ra dichloride) enhances various carcinomas’ sensitivity to lysis by antigen-specific cytotoxic T lymphocytes through calreticulin-mediated immunogenic modulation

    PubMed Central

    Malamas, Anthony S.; Gameiro, Sofia R.; Knudson, Karin M.; Hodge, James W.

    2016-01-01

    Radium-223 dichloride (Xofigo®; 223Ra) is an alpha-emitting radiopharmaceutical FDA-approved for the treatment of bone metastases in patients with advanced castration-resistant prostate cancer. It is also being examined clinically in patients with breast and lung carcinoma and patients with multiple myeloma. As with other forms of radiation, the aim of 223Ra is to reduce tumor burden by directly killing tumor cells. External beam (photon) and proton radiation have been shown to augment tumor sensitivity to antigen-specific CD8+ cytotoxic T lymphocytes (CTLs). However, little is known about whether treatment with 223Ra can also induce such immunogenic modulation in tumor cells that survive irradiation. We examined these effects in vitro by exposing human prostate, breast, and lung carcinoma cells to sublethal doses of 223Ra. 223Ra significantly enhanced T cell-mediated lysis of each tumor type by CD8+ CTLs specific for MUC-1, brachyury, and CEA tumor antigens. Immunofluorescence analysis revealed that the increase in CTL killing was accompanied by augmented protein expression of MHC-I and calreticulin in each tumor type, molecules that are essential for efficient antigen presentation. Enhanced tumor-cell lysis was facilitated by calreticulin surface translocation following 223Ra exposure. The phenotypic changes observed after treatment appear to be mediated by induction of the endoplasmic reticulum stress response pathway. By rendering tumor cells more susceptible to T cell-mediated lysis, 223Ra may potentially be effective in combination with various immunotherapies, particularly cancer vaccines that are designed to generate and expand patients’ endogenous antigen-specific T-cell populations against specific tumor antigens. PMID:27893426

  11. Oncogenic transformation of C3H 10T1/2 cells exposed to alpha particles: Sensitivity through the cell cycle

    SciTech Connect

    Bettega, D.; Calzolari, P.; Chiorda, G.N.

    1995-06-01

    Oncogenic transformation of synchronized C3H 10T1/2 cells was determined after exposure to 4.3 MeV {alpha} particles (LET = 101 keV/{mu}m). Two synchronization techniques were tested using basic and modified protocols: one based on the release of cells from contact inhibition and the second on the mitotic shake-off method. Progression of cells through the cycle was followed as a function of time by flow cytometric analysis, DNA labeling for passage through S phase, the growth curve for the cell number and mitotic index measurements. The conclusion is that, although the release of cells from confluence provides higher yields of synchronized cells, mitotic shake-off proved to be the best way of collecting a synchronized population of minimally perturbed cells. Cells synchronized by mitotic shake-off were irradiated with 0.30 Gy in the interval between 2 and 10 h corresponding to G{sub 1} and early S phases. For comparison asynchronous populations were irradiated in parallel. Oncogenic transformation frequency, corrected for background, in mid-G{sub 1} phase was (18 {+-} 4) x 10{sup {minus}5} (average values of frequencies at 4 and 6 h) compared with the value of (8 {+-} 4) x 10{sup {minus}5} for the asynchronous population. While these data are suggestive of a trend toward a slightly increased sensitivity in mid-G{sub 1} phase, it is not statistically significant. The surviving fraction is constant in G{sub 1} phase. 14 refs., 2 figs., 2 tabs.

  12. Sublethal exposure to alpha radiation (223Ra dichloride) enhances various carcinomas' sensitivity to lysis by antigen-specific cytotoxic T lymphocytes through calreticulin-mediated immunogenic modulation.

    PubMed

    Malamas, Anthony S; Gameiro, Sofia R; Knudson, Karin M; Hodge, James W

    2016-12-27

    Radium-223 dichloride (Xofigo®; 223Ra) is an alpha-emitting radiopharmaceutical FDA-approved for the treatment of bone metastases in patients with advanced castration-resistant prostate cancer. It is also being examined clinically in patients with breast and lung carcinoma and patients with multiple myeloma. As with other forms of radiation, the aim of 223Ra is to reduce tumor burden by directly killing tumor cells. External beam (photon) and proton radiation have been shown to augment tumor sensitivity to antigen-specific CD8+ cytotoxic T lymphocytes (CTLs). However, little is known about whether treatment with 223Ra can also induce such immunogenic modulation in tumor cells that survive irradiation. We examined these effects in vitro by exposing human prostate, breast, and lung carcinoma cells to sublethal doses of 223Ra. 223Ra significantly enhanced T cell-mediated lysis of each tumor type by CD8+ CTLs specific for MUC-1, brachyury, and CEA tumor antigens. Immunofluorescence analysis revealed that the increase in CTL killing was accompanied by augmented protein expression of MHC-I and calreticulin in each tumor type, molecules that are essential for efficient antigen presentation. Enhanced tumor-cell lysis was facilitated by calreticulin surface translocation following 223Ra exposure. The phenotypic changes observed after treatment appear to be mediated by induction of the endoplasmic reticulum stress response pathway. By rendering tumor cells more susceptible to T cell-mediated lysis, 223Ra may potentially be effective in combination with various immunotherapies, particularly cancer vaccines that are designed to generate and expand patients' endogenous antigen-specific T-cell populations against specific tumor antigens.

  13. A simple highly sensitive and selective aptamer-based colorimetric sensor for environmental toxins microcystin-LR in water samples.

    PubMed

    Li, Xiuyan; Cheng, Ruojie; Shi, Huijie; Tang, Bo; Xiao, Hanshuang; Zhao, Guohua

    2016-03-05

    A simple and highly sensitive aptamer-based colorimetric sensor was developed for selective detection of Microcystin-LR (MC-LR). The aptamer (ABA) was employed as recognition element which could bind MC-LR with high-affinity, while gold nanoparticles (AuNPs) worked as sensing materials whose plasma resonance absorption peaks red shifted upon binding of the targets at a high concentration of sodium chloride. With the addition of MC-LR, the random coil aptamer adsorbed on Au NPs altered into regulated structure to form MC-LR-aptamer complexes and broke away from the surface of Au NPs, leading to the aggregation of AuNPs, and the color converted from red to blue due to the interparticle plasmon coupling. Results showed that our aptamer-based colorimetric sensor exhibited rapid and sensitive detection performance for MC-LR with linear range from 0.5 nM to 7.5 μM and the detection limit reached 0.37 nM. Meanwhile, the pollutants usually coexisting with MC-LR in pollutant water samples had not demonstrated disturbance for detecting of MC-LR. The mechanism was also proposed suggesting that high affinity interaction between aptamer and MC-LR significantly enhanced the sensitivity and selectivity for MC-LR detection. Besides, the established method was utilized in analyzing real water samples and splendid sensitivity and selectivity were obtained as well.

  14. Selective Enhancement of Dopamine Release in the Ventral Pallidum of Methamphetamine-Sensitized Mice

    PubMed Central

    2016-01-01

    Drugs of abuse induce sensitization, which is defined as enhanced response to additional drug following a period of withdrawal. Sensitization occurs in both humans and animal models of drug reinforcement and contributes substantially to the addictive nature of drugs of abuse, because it is thought to represent enhanced motivational wanting for drug. The ventral pallidum, a key member of the reward pathway, contributes to behaviors associated with reward, such as sensitization. Dopamine inputs to the ventral pallidum have not been directly characterized. Here we provide anatomical, neurochemical, and behavioral evidence demonstrating that dopamine terminals in the ventral pallidum contribute to reward in mice. We report subregional differences in dopamine release, measured by ex vivo fast-scan cyclic voltammetry: rostral ventral pallidum exhibits increased dopamine release and uptake compared with caudal ventral pallidum, which is correlated with tissue expression of dopaminergic proteins. We then subjected mice to a methamphetamine-sensitization protocol to investigate the contribution of dopaminergic projections to the region in reward related behavior. Methamphetamine-sensitized animals displayed a 508% and 307% increase in baseline dopamine release in the rostral and caudal ventral pallidum, respectively. Augmented dopamine release in the rostral ventral pallidum was significantly correlated with sensitized locomotor activity. Moreover, this presynaptic dopaminergic plasticity occurred only in the ventral pallidum and not in the ventral or dorsal striatum, suggesting that dopamine release in the ventral pallidum may be integrally important to drug-induced sensitization. PMID:27501345

  15. Vibration isolation technology: Sensitivity of selected classes of experiments to residual accelerations

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan D.

    1990-01-01

    The solution was sought of a 2-D axisymmetric moving boundary problem for the sensitivity of isothermal and nonisothermal liquid columns and the sensitivity of thermo-capillary flows to buoyancy driven convection caused by residual accelerations. The sensitivity of a variety of space experiments to residual accelerations are examined. In all the cases discussed, the sensitivity is related to the dynamic response of a fluid. In some cases the sensitivity can be defined by the magnitude of the response of the velocity field. This response may involve motion of the fluid associated with internal density gradients, or the motion of a free liquid surface. For fluids with internal density gradients, the type of acceleration to which the experiment is sensitive will depend on whether buoyancy driven convection must be small in comparison to other types of fluid motion (such as thermocapillary flow), or fluid motion must be suppressed or eliminated (such as in diffusion studies, or directional solidification experiments). The effect of the velocity on the composition and temperature field must be considered, particularly in the vicinity of the melt crystal interface. As far as the response to transient disturbances is concerned the sensitivity is determined by both the magnitude and frequency the acceleration and the characteristic momentum and solute diffusion times.

  16. Mitogen-activated protein kinase kinase 1/extracellular signal-regulated kinase (MEK-1/ERK) inhibitors sensitize reduced glucocorticoid response mediated by TNF{alpha} in human epidermal keratinocytes (HaCaT)

    SciTech Connect

    Onda, Kenji . E-mail: knjond@ps.toyaku.ac.jp; Nagashima, Masahiro; Kawakubo, Yo; Inoue, Shota; Hirano, Toshihiko; Oka, Kitaro

    2006-12-08

    Glucocorticoids (GCs) are essential drugs administered topically or systematically for the treatment of autoimmune skin diseases such as pemphigus. However, a certain proportion of patients does not respond well to GCs. Although studies on the relationship between cytokines and GC insensitivity in local tissues have attracted attention recently, little is known about the underlying mechanism(s) for GC insensitivity in epidermal keratinocytes. Here, we report that tumor necrosis factor (TNF) {alpha} reduces GC-induced transactivation of endogenous genes as well as a reporter plasmid which contains GC responsive element (GRE) in human epidermal keratinocyte cells (HaCaT). The GC insensitivity by TNF{alpha} was not accompanied by changes in mRNA expressions of GR isoforms ({alpha} or {beta}). However, we observed that mitogen-activated protein kinase kinase-1/extracellular signal-regulated kinase (MEK-1/ERK) inhibitors (PD98059 and U0126) significantly sensitized the GC-induced transactivation of anti-inflammatory genes (glucocorticoid-induced leucine zipper (GILZ) and mitogen-activated protein kinase phosphatase (MKP)-1) and FK506 binding protein (FKBP) 51 gene in the presence of TNF{alpha}. Additionally, we observed that TNF{alpha} reduced prednisolone (PSL)-dependent nuclear translocation of GR, which was restored by pre-treatment of MEK-1 inhibitors. This is the first study demonstrating a role of the MEK-1/ERK cascade in TNF{alpha}-mediated GC insensitivity. Our data suggest that overexpression of TNF{alpha} leads to topical GC insensitivity by reducing GR nuclear translocation in keratinocytes, and our findings also suggest that inhibiting the MEK-1/ERK cascade may offer a therapeutic potential for increasing GC efficacy in epidermis where sufficient inflammatory suppression is required.

  17. Vibration isolation technology: Sensitivity of selected classes of space experiments to residual accelerations

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan D.; Zhang, Y. Q.; Adebiyi, Adebimpe

    1989-01-01

    Progress performed on each task is described. Order of magnitude analyses related to liquid zone sensitivity and thermo-capillary flow sensitivity are covered. Progress with numerical models of the sensitivity of isothermal liquid zones is described. Progress towards a numerical model of coupled buoyancy-driven and thermo-capillary convection experiments is also described. Interaction with NASA personnel is covered. Results to date are summarized and they are discussed in terms of the predicted space station acceleration environment. Work planned for the second year is also discussed.

  18. Head-to-head comparisons of carbon fiber microelectrode coatings for sensitive and selective neurotransmitter detection by voltammetry.

    PubMed

    Singh, Yogesh S; Sawarynski, Lauren E; Dabiri, Pasha D; Choi, Wonwoo R; Andrews, Anne M

    2011-09-01

    Voltammetry is widely used to investigate neurotransmission and other biological processes but is limited by poor chemical selectivity and fouling of commonly used carbon fiber microelectrodes (CFMs). We performed direct comparisons of three key coating materials purported to impart selectivity and fouling resistance to electrodes: Nafion, base-hydrolyzed cellulose acetate (BCA), and fibronectin. We systematically evaluated the impact on a range of electrode parameters. Fouling due to exposure to brain tissue was investigated using an approach that minimizes the use of animals while enabling evaluation of statistically significant populations of electrodes. We find that BCA is relatively fouling-resistant. Moreover, detection at BCA-coated CFMs can be tuned by altering hydrolysis times to minimize the impact on sensitivity losses while maintaining fouling resistance. Fibronectin coating is associated with moderate losses in sensitivity after coating and fouling. Nafion imparts increased sensitivity for dopamine and norepinephrine but not serotonin, as well as the anticipated selectivity for cationic neurotransmitters over anionic metabolites. Although Nafion has been suggested to resist fouling, both dip-coating and electrodeposition of Nafion are associated with substantial fouling, similar to levels observed at bare electrodes after exposure to brain tissue. Direct comparisons of these coatings identified unique electroanalytical properties of each that can be used to guide selection tailored to the goals and environment of specific studies.

  19. Selective enrichment and sensitive detection of candidate disease biomarker using a novel surfactant-coated magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Capangpangan, R. Y.; dela Rosa, M. A. C.; Chang, C. H.; Wang, W. C.; Peng, J.; Shih, S. J.; Chiang, M. H.; Tzou, D. L.; Lin, C. C.; Chen, Y. J.

    2014-08-01

    In this study, novel surfactant-coated magnetic nanoparticles were synthesized and evaluated for enrichment performance towards the sensitive detection of disease biomarkers. Surfactants with phosphate ester groups (RD35A and RD66) were used as a coating to reduce aggregation and to enhance the nanoparticle dispersion. Importantly, sensitive enrichment of the target proteins using the antibody-functionalized magnetic nanoparticles (Ab@MNP) was obtained, with a five-fold increase in recovery compared to uncoated magnetic nanoparticles. Similarly, phosphopeptide enrichment using the NTA@MNP in standard samples showed that the nanoparticles could selectively enrich phosphorylated peptides.

  20. Differential Sensitivity of Meloidogyne spp. and Heterodera glycines to Selected Nematicides.

    PubMed

    Gourd, T R; Schmitt, D P; Barker, K R

    1993-12-01

    Differential sensitivity of Meloidogyne arenaria, M. hapla, M. incognita, M. javanica, and Heterodera glycines races 1 and 5 to the nonfumigant nematicides aldicarb, ethoprop, and fenamiphos was evaluated using a 48-hour root-penetration bioassay. Generally, H. glycines was more tolerant of the nematicides, especially ethoprop, than were the Meloidogyne species. Among Meloidogyne species, M. incognita was most sensitive to aldicarb and fenamiphos, but its reaction to ethoprop was similar to the other three Meloidogyne species.

  1. Cloning of the human skeletal muscle {alpha}{sub 1} subunit of the dihydropyridine-sensitive L-type calcium channel (CACNL1A3)

    SciTech Connect

    Hogan, K.; Powers, P.A.; Gregg, R.G.

    1994-12-01

    Skeletal muscle contraction is initiated by release of calcium stored in the sarcoplasmic reticulum in response to membrane depolarization transduced by the L-type voltage-dependent calcium channels (VDCCs) present in the transverse tubule. The L-type VDCC purified from rabbit skeletal muscle transverse tubules is a pentamer composed of {alpha}{sub 1}, {alpha}{sub 2}, {Beta},{delta}, and {gamma} subunits. Here, we report the sequence of the human {alpha}{sub 1} subunit. 8 refs., 1 fig.

  2. Evaluation of a rapid radiometric differentiation test for the Mycobacterium tuberculosis complex by selective inhibition with p-nitro-alpha-acetylamino-beta-hydroxypropiophenone

    SciTech Connect

    Laszlo, A.; Siddiqi, S.H.

    1984-05-01

    This study is an evaluation of a rapid technique for the differentiation of the Mycobacterium tuberculosis complex from other mycobacteria, using p-nitro-alpha-acetylamino-beta- hydroxypropiophenone (NAP) as a selective inhibitory agent. A total of 416 coded cultures, 234 cultures belonging to the M. tuberculosis complex and 182 cultures belonging to 35 other mycobacterial species, were tested in two laboratories for p-nitro-alpha-acetylamino-beta- hydroxypropiophenone inhibition to concentrations of 5 and 10 micrograms of NAP per ml in Middlebrook 7H12 liquid medium. Two testing modes were compared: the indirect, in which a large bacterial inoculum was used from an isolated culture on a solid medium, and the direct, which used a small inoculum from 7H12 medium. A decrease or no increase in daily /sup 14/CO/sub 2/ output as measured by a BACTEC system was considered evidence of inhibition. The data presented show that a concentration of 5 micrograms of NAP per ml can effectively separate the M. tuberculosis complex from other mycobacterial species in 4 to 6 days. The direct test data show that, unlike other conventional biochemical tests, it does not require a heavy inoculum of mycobacteria and can therefore be performed soon after growth is detected by the radiometric method.

  3. Genomic organization and differential signature of positive selection in the alpha and beta globin gene clusters in two cetacean species.

    PubMed

    Nery, Mariana F; Arroyo, José Ignacio; Opazo, Juan C

    2013-01-01

    The hemoglobin of jawed vertebrates is a heterotetramer protein that contains two α- and two β-chains, which are encoded by members of α- and β-globin gene families. Given the hemoglobin role in mediating an adaptive response to chronic hypoxia, it is likely that this molecule may have experienced a selective pressure during the evolution of cetaceans, which have to deal with hypoxia tolerance during prolonged diving. This selective pressure could have generated a complex history of gene turnover in these clusters and/or changes in protein structure themselves. Accordingly, we aimed to characterize the genomic organization of α- and β-globin gene clusters in two cetacean species and to detect a possible role of positive selection on them using a phylogenetic framework. Maximum likelihood and Bayesian phylogeny reconstructions revealed that both cetacean species had retained a similar complement of putatively functional genes. For the α-globin gene cluster, the killer whale presents a complement of genes composed of HBZ, HBK, and two functional copies of HBA and HBQ genes, whereas the dolphin possesses HBZ, HBK, HBA and HBQ genes, and one HBA pseudogene. For the β-globin gene cluster, both species retained a complement of four genes, two early expressed genes-HBE and HBH-and two adult expressed genes-HBD and HBB. Our natural selection analysis detected two positively selected sites in the HBB gene (56 and 62) and four in HBA (15, 21, 49, 120). Interestingly, only the genes that are expressed during the adulthood showed the signature of positive selection.

  4. Central venous hypoxemia is a determinant of human atrial ATP-sensitive potassium channel expression: evidence for a novel hypoxia-inducible factor 1alpha-Forkhead box class O signaling pathway.

    PubMed

    Raeis, Véronique; Philip-Couderc, Pierre; Roatti, Angela; Habre, Walid; Sierra, Jorge; Kalangos, Afksendyios; Beghetti, Maurice; Baertschi, Alex J

    2010-05-01

    ATP-sensitive potassium channels couple cell excitability to energy metabolism, thereby providing life-saving protection of stressed cardiomyocytes. The signaling for ATP-sensitive potassium channel expression is still unknown. We tested involvement of biochemical and biophysical parameters and potential transcription factors Forkhead box (FOX) and hypoxia-inducible factor (HIF-1alpha). Right atrial tissues were obtained during surgery from 28 children with heart disease. Expression of K(+)-inward-rectifier subunits Kir6.1/Kir6.2; sulfonyl urea receptors (SURs) SUR1A/B and SUR2A/B; and FOX class O (FOXO) 1, FOXO3, FOXF2, and HIF-1alpha were related to 31 parameters, including personal data, blood chemistry, and echocardiography. Venous hypoxemia (but not other ischemia indicators, such as venous hypercapnia or low glucose) predicts increased Kir6.1 (P<0.003) and Kir6.2 (P<0.03) protein. Kir6.1 associates with SUR2A/B mRNA (P<0.05) and correlates with FOXOs (P<0.002). FOXOs correlate with HIF-1alpha (P<0.01) and HIF-1alpha with venous hypoxemia (P<0.003). Electrophoretic mobility-shift assays suggest causal links among hypoxia, HIF-1alpha, FOXO1, and Kir6.1. To mimic mild ischemia encountered in some patients, cultured rat atrial myocytes were tested in hypoxia, hypercapnia, or low glucose, with normal conditions serving as the control. Mild hypoxia (24-hour) increases expression of HIF-1alpha, FOXO1, and SUR2A/B/Kir6.1 in culture (P<0.01), whereas hypercapnia and low glucose have no or opposite effects. Gene knockdown of HIF-1alpha or FOXO1 by small-interfering RNAs abolishes hypoxia-induced expression of FOXO1 and SUR2A/B/Kir6.1. These results suggest that low tissue oxygen determines increased expression of the atrial SUR2A/B/Kir6.1 gene via activation of HIF-1alpha-FOXO1. Because increased SUR2A/B/Kir6.1 has known survival benefits, this pathway offers novel therapeutic targets for children with heart disease.

  5. Sensitivity and Specificity Improvement in Abdominal Obesity Diagnosis Using Cluster Analysis during Waist Circumference Cut-Off Point Selection

    PubMed Central

    Bermúdez, Valmore; Añez, Roberto; Toledo, Alexandra; Bello, Luis; Apruzzese, Vanessa; González, Robys; Chacín, Maricarmen; Cabrera, Mayela; Cano, Clímaco; Velasco, Manuel; López-Miranda, José

    2015-01-01

    Introduction. The purpose of this study was to analyze the influence of metabolic phenotypes during the construction of ROC curves for waist circumference (WC) cutpoint selection. Materials and Methods. A total of 1,902 subjects of both genders were selected from the Maracaibo City Metabolic Syndrome Prevalence Study database. Two-Step Cluster Analysis (TSCA) was applied to select metabolically healthy and sick men and women. ROC curves were constructed to determine WC cutoff points by gender. Results. Through TSCA, metabolic phenotype predictive variables were selected: HOMA2-IR and HOMA2-βcell for women and HOMA2-IR, HOMA2-βcell, and TAG for men. Subjects were classified as healthy normal weight, metabolically obese normal weight, healthy and metabolically disturbed overweight, and healthy and metabolically disturbed obese. Final WC cutpoints were 91.50 cm for women (93.4% sensitivity, 93.7% specificity) and 98.15 cm for men (96% sensitivity, 99.5% specificity). Conclusions. TSCA in the selection of the groups used in ROC curves construction proved to be an important tool, aiding in the detection of MOWN and MHO which cannot be identified with WC alone. The resulting WC cutpoints were <91.00 cm for women and <98.00 cm for men. Furthermore, anthropometry is insufficient to determine healthiness, and, biochemical analysis is needed to properly filter subjects during classification. PMID:25945356

  6. Highly sensitive and selective detection of beryllium ions using a microcantilever modified with benzo-9-crown-3 doped hydrogel.

    PubMed

    Peng, Rong-Peng; Chen, Bin; Ji, Hai-Feng; Wu, Li-Zhu; Tung, Chen-Ho

    2012-03-07

    A microcantilever sensor modified by chitosan/gelatin hydrogels that are doped with benzo-9-crown-3 has been developed for the sensitive and selective detection of beryllium ions in an aqueous solution. The microcantilever undergoes bending deflection upon exposure to Be(2+) due to selective absorption of Be(2+) in the hydrogel. The detection limit is 10(-11) M. Other metal ions, such as Li(+), Na(+), K(+), Mg(2+), and Ca(2+), have a marginal effect on the deflection of the microcantilever. The mechanism of the bending is discussed and the results showed that the microcantilever may be used for in situ detection of beryllium.

  7. Redox-sensitivity and mobility of selected pharmaceutical compounds in a laboratory column experiment

    NASA Astrophysics Data System (ADS)

    Banzhaf, S.; Nödler, K.; Licha, T.; Krein, A.; Scheytt, T.

    2012-04-01

    Laboratory column experiments are suitable to investigate the sediment water interaction and to study the transport behaviour of solutes. Processes like retardation and degradation can be identified and quantified. The conducted experiment, which is closely connected to a field study in Luxembourg, investigated the transport behaviour of selected pharmaceutical compounds and their redox-dependent metabolism under water saturated conditions. Fine-grained natural sediment with a low hydraulic conductivity from a study site in Luxembourg was filled into the column. The water for the experiment was taken from a small stream at the same fieldsite. It was spiked with four pharmaceutical compounds (carbamazepine, diclofenac, ibuprofen, sulfamethoxazole) with concentrations between 170 and 300 ng/L for the different substances. The chosen pharmaceuticals were also detected in groundwater and surface water samples at the study site and used to qualify exchange/mixing of surface water and groundwater (BANZHAF et al., 2011). As some of the substances are known to exhibit redox-sensitive degradation, the redox-conditions were systematically varied throughout the experiment. This was realised by adding nitrate at the inflow of the column. During the experiment, which lasted for 2.5 months, four different nitrate concentrations (20-130 mg/L) were applied, beginning with the highest concentration. During the experiment water from the reservoir tank was sampled daily in order to detect a potential degradation of the pharmaceutical compounds before they enter the column. The effluent water was sampled every three hours to guarantee a maximum resolution for the analysis of the pharmaceuticals where necessary. In addition, major ions were analysed in the influent and effluent samples. Throughout the experiment physicochemical parameters (oxidation reduction potential (ORP), dissolved oxygen, electrical conductivity, and pH-value) were measured and logged at the outflow of the column

  8. A Post-Synthetically Modified MOF for Selective and Sensitive Aqueous-Phase Detection of Highly Toxic Cyanide Ions.

    PubMed

    Karmakar, Avishek; Kumar, Naveen; Samanta, Partha; Desai, Aamod V; Ghosh, Sujit K

    2016-01-18

    Selective and sensitive detection of toxic cyanide (CN(-) ) by a post-synthetically altered metal-organic framework (MOF) has been achieved. A post-synthetic modification was employed in the MOF to incorporate the specific recognition site with the CN(-) ion over all other anions, such as Cl(-) , Br(-) , and SCN(-) . The aqueous-phase sensing and very low detection limit, the essential prerequisites for an effective sensory material, have been fulfilled by the MOF. Moreover, the present detection level meets the standard set by the World Health Organization (WHO) for the permissible limit of cyanide concentration in drinking water. The utilization of MOF-based materials as the fluorometric probes for selective and sensitive detection of CN(-) ions has not been explored till now.

  9. A label-free fluorescent aptasensor for selective and sensitive detection of streptomycin in milk and blood serum.

    PubMed

    Taghdisi, Seyed Mohammad; Danesh, Noor Mohammad; Nameghi, Morteza Alinezhad; Ramezani, Mohammad; Abnous, Khalil

    2016-07-15

    Sensitive and fast detection of antibiotic residues in animal derived foods and blood serum is of great interest. In this study a fluorescent aptasensor was designed for selective and sensitive detection of streptomycin (STR) based on Exonuclease III (Exo III), SYBR Gold and aptamer complimentary strand. In the absence of STR, the fluorescence intensity is weak. Upon addition of STR, the aptamer binds to its target, leading to release of complementary strand from aptamer and more protection against Exo III function. Following addition of SYBR Gold, a strong fluorescence intensity is obtained. This aptasensor showed a high selectivity toward STR with a limit of detection (LOD) as low as 54.5 nM. The validity of the procedure and applicability of the aptasensor were successfully assessed by detection of STR in a spiked milk and blood serum without interference from the sample matrix.

  10. Melanoma prevention by MC1R selective small peptide analogs of alpha MSH | Division of Cancer Prevention

    Cancer.gov

    DESCRIPTION (provided by applicant): This revised application will test the hypothesis that small peptide analogs of α-melanocortin (α-MSH) that are selective agonists of the melanocortin 1 receptor (MC1R) will prevent melanoma tumor formation in transgenic mouse melanoma models by enhancing repair of ultraviolet radiation (UV)-induced DNA damage and stimulating melanogenesis. |

  11. Green synthesis of carbon nanodots as an effective fluorescent probe for sensitive and selective detection of mercury(II) ions

    NASA Astrophysics Data System (ADS)

    Lu, Wenbo; Qin, Xiaoyun; Asiri, Abdullah M.; Al-Youbi, Abdulrahman O.; Sun, Xuping

    2013-01-01

    The present communication reports on the use of sweet potatoes as carbon source for green synthesis of fluorescent carbon nanodots (CNDs) ranging from 1 to 3 nm. We further demonstrate the use of such CNDs as a very effective fluorescent probe for label-free, sensitive, and selective detection of Hg2+ with a detection limit as low as 1 nM. The feasibility of the CNDs for analysis of Hg2+ in a real water sample is also demonstrated successfully.

  12. Sensitivity analysis of add-on price estimate for select silicon wafering technologies

    NASA Technical Reports Server (NTRS)

    Mokashi, A. R.

    1982-01-01

    The cost of producing wafers from silicon ingots is a major component of the add-on price of silicon sheet. Economic analyses of the add-on price estimates and their sensitivity internal-diameter (ID) sawing, multiblade slurry (MBS) sawing and fixed-abrasive slicing technique (FAST) are presented. Interim price estimation guidelines (IPEG) are used for estimating a process add-on price. Sensitivity analysis of price is performed with respect to cost parameters such as equipment, space, direct labor, materials (blade life) and utilities, and the production parameters such as slicing rate, slices per centimeter and process yield, using a computer program specifically developed to do sensitivity analysis with IPEG. The results aid in identifying the important cost parameters and assist in deciding the direction of technology development efforts.

  13. Selective skin sensitivity changes and sensory reweighting following short-duration space flight.

    PubMed

    Lowrey, Catherine R; Perry, Stephen D; Strzalkowski, Nicholas D J; Williams, David R; Wood, Scott J; Bent, Leah R

    2014-03-15

    Skin sensory input from the foot soles is coupled with vestibular input to facilitate body orientation in a gravitational environment. Anecdotal observations suggest that foot sole skin becomes hypersensitive following space flight. The veritable level of skin sensitivity and its impact on postural disequilibrium observed post space flight have not been documented. Skin sensitivity of astronauts (n = 11) was measured as vibration perception at the great toe, fifth metatarsal and heel. Frequencies targeted four classes of receptors: 3 and 25 Hz for slow-adapting (SA) receptors and 60 and 250 Hz for fast-adapting (FA) receptors. Data were collected pre- and post-space flight. We hypothesized that skin sensitivity would increase post-space flight and correlate to balance measures. Decreased skin sensitivity was found on landing day at 3 and 25 Hz on the great toe. Hypersensitivity was found for a subset of astronauts (n = 6) with significantly increased sensitivity to 250 Hz at the heel. This subset displayed a greater reduction in computerized dynamic posturography (CDP) equilibrium (EQ) scores (-54%) on landing vs. non-hypersensitive participants (-11%). Observed hyposensitivity of SA (pressure) receptors may indicate a strategy to reduce pressure input during periods of unloading. Hypersensitivity of FAs coupled with reduced EQ scores may reflect targeted sensory reweighting. Altered gravito-inertial environments reduce vestibular function in balance control which may trigger increased weighting of FAs (that signal foot contact, slips). Understanding modulations to skin sensitivity has translational implications for mitigating postural disequilibrium following space flight and for on-Earth preventative strategies for imbalance in older adults.

  14. Fluorescent Gold Nanoprobes for the Sensitive and Selective Detection for Hg2+

    NASA Astrophysics Data System (ADS)

    Chai, Fang; Wang, Tingting; Li, Lu; Liu, Haiyan; Zhang, Lingyu; Su, Zhongmin; Wang, Chungang

    2010-11-01

    A simple, cost-effective yet rapid and sensitive sensor for on-site and real-time Hg2+ detection based on bovine serum albumin functionalized fluorescent gold nanoparticles as novel and environmentally friendly fluorescent probes was developed. Using this probe, aqueous Hg2+ can be detected at 0.1 nM in a facile way based on fluorescence quenching. This probe was also applied to determine the Hg2+ in the lake samples, and the results demonstrate low interference and high sensitivity.

  15. Cell-line selectivity improves the predictive power of pharmacogenomic analyses and helps identify NADPH as biomarker for ferroptosis sensitivity

    PubMed Central

    Shimada, Kenichi; Hayano, Miki; Pagano, Nen; Stockwell, Brent

    2016-01-01

    Precision medicine in oncology requires not only identification of cancer-associated mutations, but also effective drugs for each cancer genotype, which is still a largely unsolved problem. One approach for the latter challenge has been large-scale testing of small molecules in genetically characterized cell lines. We hypothesized that compounds with high cell-line-selective lethality exhibited consistent results across such pharmacogenomic studies. We analyzed the compound sensitivity data of 6,259 lethal compounds from the NCI-60 project. 2,565 cell-line-selective lethal compounds were identified and grouped into 18 clusters based on their GI50 profiles across the 60 cell lines, which were shown to represent distinct mechanisms of action. Further transcriptome analysis revealed a biomarker, NADPH abundance, for predicting sensitivity to ferroptosis-inducing compounds, which we experimentally validated. In summary, incorporating cell-line selectivity filters improves the predictive power of pharmacogenomic analyses and enables discovery of biomarkers that predict the sensitivity of cells to specific cell death inducers. PMID:26853626

  16. Cell-Line Selectivity Improves the Predictive Power of Pharmacogenomic Analyses and Helps Identify NADPH as Biomarker for Ferroptosis Sensitivity.

    PubMed

    Shimada, Kenichi; Hayano, Miki; Pagano, Nen C; Stockwell, Brent R

    2016-02-18

    Precision medicine in oncology requires not only identification of cancer-associated mutations but also effective drugs for each cancer genotype, which is still a largely unsolved problem. One approach for the latter challenge has been large-scale testing of small molecules in genetically characterized cell lines. We hypothesized that compounds with high cell-line-selective lethality exhibited consistent results across such pharmacogenomic studies. We analyzed the compound sensitivity data of 6,259 lethal compounds from the NCI-60 project. A total of 2,565 cell-line-selective lethal compounds were identified and grouped into 18 clusters based on their median growth inhibitory GI50 profiles across the 60 cell lines, which were shown to represent distinct mechanisms of action. Further transcriptome analysis revealed a biomarker, NADPH abundance, for predicting sensitivity to ferroptosis-inducing compounds, which we experimentally validated. In summary, incorporating cell-line-selectivity filters improves the predictive power of pharmacogenomic analyses and enables discovery of biomarkers that predict the sensitivity of cells to specific cell death inducers.

  17. A Highly Sensitive Diketopyrrolopyrrole-Based Ambipolar Transistor for Selective Detection and Discrimination of Xylene Isomers.

    PubMed

    Wang, Bin; Huynh, Tan-Phat; Wu, Weiwei; Hayek, Naseem; Do, Thu Trang; Cancilla, John C; Torrecilla, Jose S; Nahid, Masrur Morshed; Colwell, John M; Gazit, Oz M; Puniredd, Sreenivasa Reddy; McNeill, Christopher R; Sonar, Prashant; Haick, Hossam

    2016-06-01

    An ambipolar poly(diketopyrrolopyrrole-terthiophene)-based field-effect transistor (FET) sensitively detects xylene isomers at low ppm levels with multiple sensing features. Combined with pattern-recognition algorithms, a sole ambipolar FET sensor, rather than arrays of sensors, can discriminate highly similar xylene structural isomers from one another.

  18. Vibration isolation technology: Sensitivity of selected classes of experiments to residual accelerations

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan D.

    1991-01-01

    Work was completed on all aspects of the following tasks: order of magnitude estimates; thermo-capillary convection - two-dimensional (fixed planar surface); thermo-capillary convection - three-dimensional and axisymmetric; liquid bridge/floating zone sensitivity; transport in closed containers; interaction: design and development stages; interaction: testing flight hardware; and reporting. Results are included in the Appendices.

  19. In vitro sensitivity of Hungarian Actinobaculum suis strains to selected antimicrobials.

    PubMed

    Biksi, I; Major, Andrea; Fodor, L; Szenci, O; Vetési, F

    2003-01-01

    In vitro antimicrobial sensitivity of 12 Hungarian isolates and the type strain ATCC 33144 of Actinobaculum suis to different antimicrobial compounds was determined both by the agar dilution and by the disc diffusion method. By agar dilution, MIC50 values in the range of 0.05-3.125 micrograms/ml were determined for penicillin, ampicillin, ceftiofur, doxycycline, tylosin, pleuromutilins, chloramphenicol, florfenicol, enrofloxacin and lincomycin. The MIC50 value of oxytetracycline and spectinomycin was 6.25 and 12.5 micrograms/ml, respectively. For ofloxacin, flumequine, neomycin, streptomycin, gentamicin, nalidixic acid, nitrofurantoin and sulphamethoxazole + trimethoprim MIC50 values were in the range of 25-100 micrograms/ml. With the disc diffusion method, all strains were sensitive to penicillin, cephalosporins examined, chloramphenicol and florfenicol, tetracyclines examined, pleuromutilins, lincomycin and tylosin. Variable sensitivity was observed for fluoroquinolones (flumequine, enrofloxacin, ofloxacin), most of the strains were susceptible to marbofloxacin. Almost all strains were resistant to aminoglycosides but most of them were sensitive to spectinomycin. A strong correlation was determined for disc diffusion and MIC results (Spearman's rho 0.789, p < 0001). MIC values of the type strain and MIC50 values of other tested strains did not differ significantly. Few strains showed a partially distinct resistance pattern for erythromycin, lincomycin and ampicillin in both methods.

  20. Direct ELISA kits as a sensitive and selective screening method for abstinence control in urine.

    PubMed

    Kirschbaum, Katrin M; Musshoff, Frank; Wilbert, Ansgar; Röhrich, Jörg; Madea, Burkhard

    2011-04-15

    In 2009 cutoff values of assessment criteria to testify abstinence control in order to estimate driving ability were standardized in Germany. The cutoff values are lower than required in existing guidelines like SAMHSA and there is critical discussion about detection of low concentrations by using immunoassay, especially concerning amphetamines in urine (50 ng/ml). In this study Direct ELISA kits were tested for their applicability to identify the absence of amphetamines, cannabinoids, opiates, cocaine, methadone and benzodiazepines in urine. Results were confirmed by LC/MS or GC/MS analyses. Sensitivity, specificity, predictive values (positive as well as negative) and overall misclassification rates were evaluated by contingency tables and were compared to ROC-analyses. Sensitivity results as well as specificity results were satisfying showing sensitivity values higher than 96% for each analyte. The amphetamine test we used showed sensitivity and specificity of 100% and 88%, respectively, even if amphetamine tests usually react with high cross-reactivity. Our study results include high discrimination at required cutoff values between positives and negatives for each drug group and demonstrate that immunological tests complying with requirements of current decreased urine cutoff values for assessment of driving ability do exist.

  1. Co-dominant effect of selected natural dye sensitizers in DSSC performance

    NASA Astrophysics Data System (ADS)

    Lim, Andery; Ekanayake, Piyasiri; Lim, Linda Biaw Leng; Bandara, J. M. R. Sarath

    2016-10-01

    Natural dyes from Ixora coccinea (RX) and Bougainvillea sp. (BG) were extracted and these individual dyes as well as the cocktail dye of RX and BG (1:1 v/v ratio) were investigated as dye sensitizers in dye sensitized solar cells (DSSCs). To analyze the capability of the dyes, various characterization methods were deployed such as incident photon-to-current efficiency (IPCE), current-to-voltage (I-V) characteristics, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that DSSC sensitized with RX performed the best with η = 0.76%, followed by the cocktail dye (η = 0.40%) and BG (η = 0.21%). This best overall performance of RX was attributed to the charge transport resistance (Rtr = 3.89 Ω), with the highest electron density (ɳs = 9.45 × 1028) and effective diffusion coefficient (Deff = 2.43 × 10- 8 m2/s), which accounted for high Jsc. Co-dominance performance of DSSC sensitized with cocktail dye was observed where the cocktail dye has demonstrated an improved Voc as compared to RX and improved Jsc against BG, suggesting individual influence from both dyes.

  2. Estimates of live-tree carbon stores in the Pacific Northwest are sensitive to model selection

    PubMed Central

    2011-01-01

    Background Estimates of live-tree carbon stores are influenced by numerous uncertainties. One of them is model-selection uncertainty: one has to choose among multiple empirical equations and conversion factors that can be plausibly justified as locally applicable to calculate the carbon store from inventory measurements such as tree height and diameter at breast height (DBH). Here we quantify the model-selection uncertainty for the five most numerous tree species in six counties of northwest Oregon, USA. Results The results of our study demonstrate that model-selection error may introduce 20 to 40% uncertainty into a live-tree carbon estimate, possibly making this form of error the largest source of uncertainty in estimation of live-tree carbon stores. The effect of model selection could be even greater if models are applied beyond the height and DBH ranges for which they were developed. Conclusions Model-selection uncertainty is potentially large enough that it could limit the ability to track forest carbon with the precision and accuracy required by carbon accounting protocols. Without local validation based on detailed measurements of usually destructively sampled trees, it is very difficult to choose the best model when there are several available. Our analysis suggests that considering tree form in equation selection may better match trees to existing equations and that substantial gaps exist, in terms of both species and diameter ranges, that are ripe for new model-building effort. PMID:21477353

  3. Potent and selective agonists of human melanocortin receptor 5: cyclic analogues of alpha-melanocyte-stimulating hormone.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Cabello, M Angeles; Maroto, Marta; Teran, Ana

    2007-05-17

    The physiological role of melanocortin receptor 5 (MC5R) in humans is not clear despite its broad presence in various peripheral sites and in the brain, cortex, and cerebellum. To differentiate between functions of this receptor and those of the other melanocortin receptors (hMC1,3,4R), peptides with improved receptor subtype selectivity are needed. The endogenous ligands, melanocortins, and their various synthetic analogues are not particularly selective for hMC5R. In this study, cyclic peptides derived from MTII, Ac-Nle-cyclo(Asp-His6-D-Phe7-Arg8-Trp-Lys)-NH2 (a pan-agonist at the melanocortin receptors) were prepared and tested in binding and functional assays on CHO cells expressing hMC1b,3-5R. The analogues included in their structures sterically constrained hydrophobic amino acids in positions 6 (His) and 8 (Arg), and the D-4,4'-biphenyl residue in position 7 (D-Phe). Several of the new compounds were selective potent agonists at hMC5R. They are exemplified by peptide 29, Ac-Nle-cyclo(Asp-Oic6-D-4,4'-Bip7-Pip8-Trp-Lys)-NH2 (Oic=octahydroindole-2-COOH; 4,4'-Bip=4,4'-biphenylalanine; Pip=pipecolic acid) of IC50=0.95 nM and EC50=0.99 nM at hMC5R and selectivity for this receptor with respect to the other melanocortin receptors greater than 5000-fold.

  4. GC-MS metabolomic differentiation of selected citrus varieties with different sensitivity to citrus huanglongbing.

    PubMed

    Cevallos-Cevallos, Juan M; Futch, David B; Shilts, Turksen; Folimonova, Svetlana Y; Reyes-De-Corcuera, José I

    2012-04-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The rapid identification of tolerant varieties is considered a critical step towards controlling HLB. GC-MS metabolite profiles were used to differentiate HLB-tolerant citrus varieties 'Poncirus trifoliata' (TR) and 'Carrizo citrange' (CAR) from HLB-sensitive varieties 'Madam Vinous sweet orange' (MV) and 'Duncan' grapefruit (DG). PCR analyses revealed that MV was the most sensitive variety followed by DG and the tolerant varieties CAR and TR. Metabolomic multivariate analysis allowed classification of the cultivars in apparent agreement with PCR results. Higher levels of the amino acids l-proline, l-serine, and l-aspartic acid, as well as the organic acids butanedioic and tetradecanoic acid, and accumulation of galactose in healthy plants were characteristic of the most sensitive variety MV when compared to all other varieties. Only galactose was significantly higher in DG when compared to the tolerant varieties TR and CAR. The tolerant varieties showed higher levels of l-glycine and mannose when compared to sensitive varieties MV and DG. Profiling of the sensitive varieties MV and DG over a 20-week period after inoculation of those with the HLB-containing material revealed strong responses of metabolites to HLB infection that differed from the response of the tolerant varieties. Significant changes of l-threonine level in the leaves from old mature flushes and l-serine, l-threonine, scyllo-inositol, hexadecanoic acid, and mannose in the leaves from young developing flushes were observed in MV. Significant changes in myo-inositol in old flushes and l-proline, indole, and xylose in new flushes were observed in DG.

  5. A Novel Strategy for Gene Selection of Microarray Data Based on Gene-to-Class Sensitivity Information

    PubMed Central

    Han, Fei; Sun, Wei; Ling, Qing-Hua

    2014-01-01

    To obtain predictive genes with lower redundancy and better interpretability, a hybrid gene selection method encoding prior information is proposed in this paper. To begin with, the prior information referred to as gene-to-class sensitivity (GCS) of all genes from microarray data is exploited by a single hidden layered feedforward neural network (SLFN). Then, to select more representative and lower redundant genes, all genes are grouped into some clusters by K-means method, and some low sensitive genes are filtered out according to their GCS values. Finally, a modified binary particle swarm optimization (BPSO) encoding the GCS information is proposed to perform further gene selection from the remainder genes. For considering the GCS information, the proposed method selects those genes highly correlated to sample classes. Thus, the low redundant gene subsets obtained by the proposed method also contribute to improve classification accuracy on microarray data. The experiments results on some open microarray data verify the effectiveness and efficiency of the proposed approach. PMID:24844313

  6. The Usefulness of Selected Physicochemical Indices, Cell Membrane Integrity and Sperm Chromatin Structure in Assessments of Boar Semen Sensitivity

    PubMed Central

    Wysokińska, A.; Kondracki, S.; Iwanina, M.

    2015-01-01

    The present work describes experiments undertaken to evaluate the usefulness of selected physicochemical indices of semen, cell membrane integrity and sperm chromatin structure for the assessment of boar semen sensitivity to processes connected with pre-insemination procedures. The experiments were carried out on 30 boars: including 15 regarded as providers of sensitive semen and 15 regarded as providers of semen that is little sensitive to laboratory processing. The selection of boars for both groups was based on sperm morphology analyses, assuming secondary morphological change incidence in spermatozoa as the criterion. Two ejaculates were manually collected from each boar at an interval of 3 to 4 months. The following analyses were carried out for each ejaculate: sperm motility assessment, sperm pH measurement, sperm morphology assessment, sperm chromatin structure evaluation and cell membrane integrity assessment. The analyses were performed three times. Semen storage did not cause an increase in the incidence of secondary morphological changes in the group of boars considered to provide sperm of low sensitivity. On the other hand, with continued storage there was a marked increase in the incidence of spermatozoa with secondary morphological changes in the group of boars regarded as producing more sensitive semen. Ejaculates of group I boars evaluated directly after collection had an approximately 6% smaller share of spermatozoa with undamaged cell membranes than the ejaculates of boars in group II (p≤0.05). In the process of time the percentage of spermatozoa with undamaged cell membranes decreased. The sperm of group I boars was characterised with a lower sperm motility than the semen of group II boars. After 1 hour of storing diluted semen, the sperm motility of boars producing highly sensitive semen was already 4% lower (p≤0.05), and after 24 hours of storage it was 6.33% lower than that of the boars that produced semen with a low sensitivity. Factors

  7. Highly Sensitive and Selective Sensor Chips with Graphene-Oxide Linking Layer.

    PubMed

    Stebunov, Yury V; Aftenieva, Olga A; Arsenin, Aleksey V; Volkov, Valentyn S

    2015-10-07

    The development of sensing interfaces can significantly improve the performance of biological sensors. Graphene oxide provides a remarkable immobilization platform for surface plasmon resonance (SPR) biosensors due to its excellent optical and biochemical properties. Here, we describe a novel sensor chip for SPR biosensors based on graphene-oxide linking layers. The biosensing assay model was based on a graphene oxide film containing streptavidin. The proposed sensor chip has three times higher sensitivity than the carboxymethylated dextran surface of a commercial sensor chip. Moreover, the demonstrated sensor chips are bioselective with more than 25 times reduced binding for nonspecific interaction and can be used multiple times. We consider the results presented here of importance for any future applications of highly sensitive SPR biosensing.

  8. Utilizing a pH-Sensitive Dye in the Selective Fluorescent Recognition of Sulfate.

    PubMed

    Agafontsev, Aleksandr M; Shumilova, Tatiana A; Panchenko, Pavel A; Janz, Sharon; Fedorova, Olga A; Kataev, Evgeny A

    2016-10-10

    A receptor containing amidopyrrole binding subunits and free amino groups, conjugated to a naphthalimide dye, has been designed and synthesized. The intrinsic selectivity of the binding motif for phosphate present in DMSO completely disappears in 10 % DMSO aqueous buffer at pH 3.6, at which the receptor is protonated. The electrostatic interactions between the receptor and an anion start to dominate, thus leading to selectivity for sulfate. The ability of the HSO4(-) anion to transfer the proton to the amino group during the recognition event suppresses the photoinduced electron transfer (PET) on the dye, resulting in a selective turn-on fluorescent response. The choice of pH of the solution for sensing is dictated by the pKa value of the dye.

  9. The effect of selective photosuppression of sensitized pathogenic microflora: Part II. Experimental validation on animals

    NASA Astrophysics Data System (ADS)

    Masychev, Viktor I.; Risovannaya, Olga N.

    2005-03-01

    Results of in vivo experiments have shown the maximum effectiveness of combined use of photo sensitizer 0,1% gel Radachlorine simultaneously with continuous and super pulse low energy irradiation of the diode laser with energy density 400 J/cm2, and power 1W. Given parameters have lead to complete elimination of Streptococcus pyogenes from inflammation foci in oral cavity of experimental animals.

  10. Vanilloids selectively sensitize thermal glutamate release from TRPV1 expressing solitary tract afferents.

    PubMed

    Hofmann, Mackenzie E; Andresen, Michael C

    2016-02-01

    Vanilloids, high temperature, and low pH activate the transient receptor potential vanilloid type 1 (TRPV1) receptor. In spinal dorsal root ganglia, co-activation of one of these gating sites on TRPV1 sensitized receptor gating by other modes. Here in rat brainstem slices, we examined glutamate synaptic transmission in nucleus of the solitary tract (NTS) neurons where most cranial primary afferents express TRPV1, but TRPV1 sensitization is unknown. Electrical shocks to the solitary tract (ST) evoked EPSCs (ST-EPSCs). Activation of TRPV1 with capsaicin (100 nM) increased spontaneous EPSCs (sEPSCs) but inhibited ST-EPSCs. High concentrations of the ultra-potent vanilloid resiniferatoxin (RTX, 1 nM) similarly increased sEPSC rates but blocked ST-EPSCs. Lowering the RTX concentration to 150 pM modestly increased the frequency of the sEPSCs without causing failures in the evoked ST-EPSCs. The sEPSC rate increased with raising bath temperature to 36 °C. Such thermal responses were larger in 150 pM RTX, while the ST-EPSCs remained unaffected. Vanilloid sensitization of thermal responses persisted in TTX but was blocked by the TRPV1 antagonist capsazepine. Our results demonstrate that multimodal activation of TRPV1 facilitates sEPSC responses in more than the arithmetic sum of the two activators, i.e. co-activation sensitizes TRPV1 control of spontaneous glutamate release. Since action potential evoked glutamate release is unaltered, the work provides evidence for cooperativity in gating TRPV1 plus a remarkable separation of calcium mechanisms governing the independent vesicle pools responsible for spontaneous and evoked release at primary afferents in the NTS.

  11. Selective sensitivity of schedule-induced activity to an operant suppression contingency.

    PubMed Central

    Allan, R W; Matthews, T J

    1992-01-01

    The sensitivity of pigeons' schedule-induced activity to operant consequences was studied in two experiments. During a 30-s interval between food presentations, a keylight stimulus brightened incrementally. Stable terminal key pecking and interim locomotor activity developed. An operant "setback" contingency was applied to activity. The contingency arranged for locomotor movements (detected by a nine-panel floorboard) to be followed by a resetting of the keylight brightness to a dimmer value and a 1-s delay of reinforcement (for individual responses). Experiment 1 showed that activity patterns were highly sensitive to their operant consequences. Accompanying key-peck rates were only transiently affected. In Experiment 2, the setback contingency was imposed during restricted portions of the trial, and differential operant control of activity was demonstrated. However, birds in this study produced higher rates of key pecking as activity rates were reduced. These results suggest that although schedule-induced activity arises in response to the temporal arrangement of stimulus events, this behavior may retain considerable sensitivity to response-consequence relations. PMID:1447542

  12. Kinetics and selectivity of mechanism-based inhibition of guinea pig hepatic and pulmonary cytochrome P450 by N-benzyl-1-aminobenzotriazole and N-alpha-methylbenzyl-1-aminobenzotriazole.

    PubMed

    Sinal, C J; Bend, J R

    1996-09-01

    The time dependence for mechanism-based inactivation of cytochrome P450 (P450)-dependent 7-pentoxyresorufin O-depentylation (PROD), 7-ethoxyresorufin O-deethylation (EROD), and 7-methoxyresorufin O-demethylation (MROD) activities by N-benzyl-1-aminobenzotriazole (BBT) and N-alpha-methylbenzyl-1-aminobenzotriazole (alpha MB) was investigated in hepatic and pulmonary microsomes from phenobarbital-treated guinea pigs. In the presence of NADPH, both compounds inhibited P450-dependent catalytic activity in a time- and concentration-dependent manner. Inactivation of hepatic PROD activity was more rapid (t1/2 = 13.2 vs. 155 min) for 0.1 microM alpha MB when compared with equimolar BBT. On the other hand, hepatic EROD inactivation was more rapid (t1/2 = 8.1 vs. 11 min) with 0.1 microM BBT, compared with equimolar alpha MB. Inactivation of pulmonary PROD activity was the most rapid and potent, with an apparent half-life for inactivation of t1/2 = 0.94 and 32.2 min for 0.025 microM alpha MB and BBT, respectively. Incubation of hepatic microsomes for 45 min in the presence of NADPH and 10 microM BBT or alpha MB resulted in > 90% inhibition of PROD, EROD, and MROD activities. After washing by repeated sedimentation and resuspension, inhibition of PROD (78%; 93% for BBT and alpha MB, respectively), EROD (80% and 50%), and MROD (15% and 3%) activities was reversed to varying degrees. We conclude that BBT and alpha MB are rapidly metabolized to products that inhibit individual P450 isozymes by both mechanism-based (P4502B and P4501A1) and reversible (P4501A2) mechanisms. Of the two inhibitors, alpha MB is relatively more potent and selective for guinea pig lung P4502B isozyme(s).

  13. MASS MEASUREMENTS BY AN ACCURATE AND SENSITIVE SELECTED ION RECORDING TECHNIQUE

    EPA Science Inventory

    Trace-level components of mixtures were successfully identified or confirmed by mass spectrometric accurate mass measurements, made at high resolution with selected ion recording, using GC and LC sample introduction. Measurements were made at 20 000 or 10 000 resolution, respecti...

  14. Brief Report: Sensitivity of Children with Autism Spectrum Disorders to Face Appearance in Selective Trust

    ERIC Educational Resources Information Center

    Li, Pengli; Zhang, Chunhua; Yi, Li

    2016-01-01

    The current study examined how children with Autism Spectrum Disorders (ASD) could selectively trust others based on three facial cues: the face race, attractiveness, and trustworthiness. In a computer-based hide-and-seek game, two face images, which differed significantly in one of the three facial cues, were presented as two cues for selective…

  15. Highly sensitive and selective determination of methylergometrine maleate using carbon nanofibers/silver nanoparticles composite modified carbon paste electrode.

    PubMed

    Kalambate, Pramod K; Rawool, Chaitali R; Karna, Shashi P; Srivastava, Ashwini K

    2016-12-01

    A highly sensitive and selective voltammetric method for determination of Methylergometrine maleate (MM) in pharmaceutical formulations, urine and blood serum samples has been developed based on enhanced electrochemical response of MM at carbon nanofibers and silver nanoparticles modified carbon paste electrode (CNF-AgNP-CPE). The electrode material was characterized by various techniques viz., X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic response of MM at CNF-AgNP-CPE was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the proposed sensor exhibits excellent electrochemical response towards MM. The DPV study shows greatly enhanced electrochemical signal for MM at CNF-AgNP-CPE lending high sensitivity to the proposed sensor for MM detection. The peak (Ip) current for MM is found to be rectilinear in the range 4.0×10(-8)-2.0×10(-5)M with a detection limit of 7.1×10(-9)M using DPV. The feasibility of the proposed sensor in analytical applications was investigated by conducting experiments on commercial pharmaceutical formulations, human urine and blood serum samples, which yielded satisfactory recoveries of MM. The proposed electrochemical sensor offers high sensitivity, selectivity, reproducibility and practical utility. We recommend it as an authentic and productive electrochemical sensor for successful determination of MM.

  16. Effective covalent immobilization of quinone and aptamer onto a gold electrode via thiol addition for sensitive and selective protein biosensing.

    PubMed

    Su, Zhaohong; Xu, Haitao; Xu, Xiaolin; Zhang, Yi; Ma, Yan; Li, Chaorong; Xie, Qingji

    2017-03-01

    Effective covalent immobilization of quinone and aptamer onto a gold electrode via thiol addition (a Michael addition) for sensitive and selective protein (with thrombin as the model) biosensing is reported, with a detection limit down to 20 fM for thrombin. Briefly, the thiol addition reaction of a gold electrode-supported 1,6-hexanedithiol (HDT) with p-benzoquinone (BQ) yielded BQ-HDT/Au, and the similar reaction of thiolated thrombin aptamer (TTA) with activated BQ-HDT/Au under 0.3V led to formation of a gold electrode-supported novel electrochemical probe TTA-BQ-HDT/Au. The thus-prepared TTA-BQ-HDT/Au exhibits a pair of well-defined redox peaks of quinone moiety, and the TTA-thrombin interaction can sensitively decrease the electrochemical signal. Herein the thiol addition acts as an effective and convenient binding protocols for aptasensing, and a new method (electrochemical conversion of Michael addition complex for signal generation) for the fabrication of biosensor is presented. The cyclic voltammetry (CV) was used to characterize the film properties. In addition, the proposed amperometric aptasensor exhibits good sensitivity, selectivity, and reproducibility. The aptasensor also has acceptable recovery for detection in complex protein sample.

  17. Mesoporous carbon nitride based biosensor for highly sensitive and selective analysis of phenol and catechol in compost bioremediation.

    PubMed

    Zhou, Yaoyu; Tang, Lin; Zeng, Guangming; Chen, Jun; Cai, Ye; Zhang, Yi; Yang, Guide; Liu, Yuanyuan; Zhang, Chen; Tang, Wangwang

    2014-11-15

    Herein, we reported here a promising biosensor by taking advantage of the unique ordered mesoporous carbon nitride material (MCN) to convert the recognition information into a detectable signal with enzyme firstly, which could realize the sensitive, especially, selective detection of catechol and phenol in compost bioremediation samples. The mechanism including the MCN based on electrochemical, biosensor assembly, enzyme immobilization, and enzyme kinetics (elucidating the lower detection limit, different linear range and sensitivity) was discussed in detail. Under optimal conditions, GCE/MCN/Tyr biosensor was evaluated by chronoamperometry measurements and the reduction current of phenol and catechol was proportional to their concentration in the range of 5.00 × 10(-8)-9.50 × 10(-6)M and 5.00 × 10(-8)-1.25 × 10(-5)M with a correlation coefficient of 0.9991 and 0.9881, respectively. The detection limits of catechol and phenol were 10.24 nM and 15.00 nM (S/N=3), respectively. Besides, the data obtained from interference experiments indicated that the biosensor had good specificity. All the results showed that this material is suitable for load enzyme and applied to the biosensor due to the proposed biosensor exhibited improved analytical performances in terms of the detection limit and specificity, provided a powerful tool for rapid, sensitive, especially, selective monitoring of catechol and phenol simultaneously. Moreover, the obtained results may open the way to other MCN-enzyme applications in the environmental field.

  18. Selective T-cell Ablation with Bismuth-213 Labeled Anti-TCR Alpha Beta as Nonmyeloablative Conditionaing for Allogeneic Canine Marrow Transplantion

    SciTech Connect

    Bethge, W. A.; Wilbur, D. Scott; Storb, R.; Hamlin, Donald K.; Santos, E. B.; Brechbiel, M. W.; Fisher, Darrell R.; Sandmaier, B. M.

    2003-06-15

    Two major immunological barriers, the host versus graft (HVG) and the graft versus host (GVH) reaction, must be overcome for successful allogeneic hematopoietic stem cell transplantation. T-cells are involved in these barriers in the major histocompatibility complex-identical settings. We hypothesized that selective ablation of T-cells using radioimmunotherapy, together with postgrafting immunosuppression, would ensure stable allogeneic engraftment. We developed a canine model of nonmyeloablative marrow transplantation in which host immune reactions are impaired by a single dose of 2 Gy total body irradiation (TBI), and where both GVH and residual HVG reactions are controlled by postgrafting immunosuppression with mycophenolate mofetil (MMF) and cyclosporine (CSP). We substituted the alpha-emitter bismuth-213 linked to a monoclonal antibody against TCR(alpha,beta)using the metal-binding chelate CHX-A”-DTPA, for 2 Gy TBI. Biodistribution studies using a gamma-emitting indium-111-labeled anti-TCR mAb showed uptake primarily in blood, marrow, lymph nodes, spleen and liver. In a dosimetry study, 4 dogs were treated with 0.13-0.46 mg/kg TCR mAb labeled with 3.7-5.6 mCi/kg (137-207 MBq/kg) Bi-213. The treatment was administered in 6 injections on days -3 and -2 followed by transplantion of dog leukocyte antigen-identical marrow on day 0 and postgrafting immunosuppression with MMF and CSP. Therapy was well tolerated except for elevations of transaminases, which were transient in all but one dog. No other organ toxicities or signs of graft-versus-host-disease were noted. The dogs had prompt allogeneic hematopoietic engraftment and achieved stable mixed donor-host hematopoietic chimerism with donor contributions ranging from 5-55 % with >30 weeks follow up.

  19. L1-Regularized Reconstruction Error as Alpha Matte

    NASA Astrophysics Data System (ADS)

    Johnson, Jubin; Cholakkal, Hisham; Rajan, Deepu

    2017-04-01

    Sampling-based alpha matting methods have traditionally followed the compositing equation to estimate the alpha value at a pixel from a pair of foreground (F) and background (B) samples. The (F,B) pair that produces the least reconstruction error is selected, followed by alpha estimation. The significance of that residual error has been left unexamined. In this letter, we propose a video matting algorithm that uses L1-regularized reconstruction error of F and B samples as a measure of the alpha matte. A multi-frame non-local means framework using coherency sensitive hashing is utilized to ensure temporal coherency in the video mattes. Qualitative and quantitative evaluations on a dataset exclusively for video matting demonstrate the effectiveness of the proposed matting algorithm.

  20. Paternal Alcohol Exposure Reduces Alcohol Drinking and Increases Behavioral Sensitivity to Alcohol Selectively in Male Offspring

    PubMed Central

    Finegersh, Andrey; Homanics, Gregg E.

    2014-01-01

    Alcohol use disorder (AUD) is heritable, but the genetic basis for this disease remains poorly understood. Although numerous gene variants have been associated with AUD, these variants account for only a small fraction of the total risk. The idea of inheritance of acquired characteristics, i.e. “epigenetic inheritance,” is re-emerging as a proven adjunct to traditional modes of genetic inheritance. We hypothesized that alcohol drinking and neurobiological sensitivity to alcohol are influenced by ancestral alcohol exposure. To test this hypothesis, we exposed male mice to chronic vapor ethanol or control conditions, mated them to ethanol-naïve females, and tested adult offspring for ethanol drinking, ethanol-induced behaviors, gene expression, and DNA methylation. We found that ethanol-sired male offspring had reduced ethanol preference and consumption, enhanced sensitivity to the anxiolytic and motor-enhancing effects of ethanol, and increased Bdnf expression in the ventral tegmental area (VTA) compared to control-sired male offspring. There were no differences among ethanol- and control-sired female offspring on these assays. Ethanol exposure also decreased DNA methylation at the BdnfÆpromoter of sire's germ cells and hypomethylation was maintained in the VTA of both male and female ethanol-sired offspring. Our findings show that paternal alcohol exposure is a previously unrecognized regulator of alcohol drinking and behavioral sensitivity to alcohol in male, but not female, offspring. Paternal alcohol exposure also induces epigenetic alterations (DNA hypomethylation) and gene expression changes that persist in the VTA of offspring. These results provide new insight into the inheritance and development of alcohol drinking behaviors. PMID:24896617

  1. Paternal alcohol exposure reduces alcohol drinking and increases behavioral sensitivity to alcohol selectively in male offspring.

    PubMed

    Finegersh, Andrey; Homanics, Gregg E

    2014-01-01

    Alcohol use disorder (AUD) is heritable, but the genetic basis for this disease remains poorly understood. Although numerous gene variants have been associated with AUD, these variants account for only a small fraction of the total risk. The idea of inheritance of acquired characteristics, i.e. "epigenetic inheritance," is re-emerging as a proven adjunct to traditional modes of genetic inheritance. We hypothesized that alcohol drinking and neurobiological sensitivity to alcohol are influenced by ancestral alcohol exposure. To test this hypothesis, we exposed male mice to chronic vapor ethanol or control conditions, mated them to ethanol-naïve females, and tested adult offspring for ethanol drinking, ethanol-induced behaviors, gene expression, and DNA methylation. We found that ethanol-sired male offspring had reduced ethanol preference and consumption, enhanced sensitivity to the anxiolytic and motor-enhancing effects of ethanol, and increased Bdnf expression in the ventral tegmental area (VTA) compared to control-sired male offspring. There were no differences among ethanol- and control-sired female offspring on these assays. Ethanol exposure also decreased DNA methylation at the BdnfÆpromoter of sire's germ cells and hypomethylation was maintained in the VTA of both male and female ethanol-sired offspring. Our findings show that paternal alcohol exposure is a previously unrecognized regulator of alcohol drinking and behavioral sensitivity to alcohol in male, but not female, offspring. Paternal alcohol exposure also induces epigenetic alterations (DNA hypomethylation) and gene expression changes that persist in the VTA of offspring. These results provide new insight into the inheritance and development of alcohol drinking behaviors.

  2. High-sensitivity, high-selectivity detection of chemical warfare agents

    NASA Astrophysics Data System (ADS)

    Pushkarsky, Michael B.; Webber, Michael E.; Macdonald, Tyson; Patel, C. Kumar N.

    2006-01-01

    We report high-sensitivity detection of chemical warfare agents (nerve gases) with very low probability of false positives (PFP). We demonstrate a detection threshold of 1.2ppb (7.7μg/m3 equivalent of Sarin) with a PFP of <1:106 in the presence of many interfering gases present in an urban environment through the detection of diisopropyl methylphosphonate, an accepted relatively harmless surrogate for the nerve agents. For the current measurement time of ˜60s, a PFP of 1:106 corresponds to one false alarm approximately every 23months. The demonstrated performance satisfies most current homeland and military security requirements.

  3. Competitive displacement: A sensitive and selective method for the detection of unlabeled molecules

    NASA Astrophysics Data System (ADS)

    Bishop, Justin; Chagovetz, Alexander M.; Blair, Steve

    2007-04-01

    We propose a new method for molecular detection that retains the sensitivity of fluorescence, but without requiring fluorescence labeling of the sample. The method works by spiking the sample solution with one or more labeled molecular species of known concentration. With proper choice of these “competitor” species, their binding kinetics can be used to quantitatively determine the concentration of unlabeled target species. This method can be applied to any fluorescence transduction mechanism that allows real-time signal acquisition, and represents an advance in mitigating certain sample processing steps. We demonstrate the method for the detection of a DNA sequence containing a single-nucleotide polymorphism (SNP).

  4. Fulvestrant, a selective estrogen receptor down-regulator, sensitizes estrogen receptor negative breast tumors to chemotherapy.

    PubMed

    Jiang, Donghai; Huang, Yuan; Han, Ning; Xu, Mingjie; Xu, Liang; Zhou, Lin; Wang, Shu; Fan, Weimin

    2014-05-01

    Drug resistance frequently results in poor prognosis and high 5-year recurrence rate in estrogen receptor-negative (ER-) breast cancer patients. Herein, we examined the reversal effects of fulvestrant on multidrug resistance (MDR) in ER- breast cancer cells. Co-administration of fulvestrant significantly sensitized ER- MDR tumors to paclitaxel both in vitro and in vivo. Further analyses indicated that fulvestrant did not affect P-gp expression, but could inhibit P-gp function and subsequently reverse P-gp mediated drug resistance in ER- breast cancer cells. These results showed that combination of fulvestrant and chemotherapeutic agents might provide an effective treatment for ER- MDR breast cancers.

  5. Toward a selective, sensitive, fast-responsive, and biocompatible two-photon probe for hydrogen sulfide in live cells.

    PubMed

    Singha, Subhankar; Kim, Dokyoung; Moon, Hyunsoo; Wang, Taejun; Kim, Ki Hean; Shin, Youn Ho; Jung, Junyang; Seo, Eunseok; Lee, Sang-Joon; Ahn, Kyo Han

    2015-01-20

    Hydrogen sulfide has emerged as an exciting endogenous gasotransmitter in addition to nitric oxide and carbon dioxide. Noninvasive detection methods for hydrogen sulfide thus become indispensable tools for studying its diverse roles in biological systems. Accordingly, fluorescent probes for hydrogen sulfide have received great attention in recent years. A practically useful fluorescent probe for bioimaging of hydrogen sulfide should be selective, sensitive, fast-responsive, biocompatible, observable in the biological optical window, and capable of deep-tissue imaging. These sensing properties, however, are extremely difficult to achieve at the same time. Disclosed here is the two-photon fluorescent probe that meets all of these criteria. The probe belongs to a Michael acceptor system, which raised a serious selectivity issue over the competing biothiols such as cysteine and glutathione. We have addressed the selectivity issue by optimizing the electronic and steric interactions between biothiols and the probe, in addition to achieving very high sensitivity, fast-response, and biocompatibility. Also, the sensing mechanism suggested in the literature was revised. The probe thus enables us to image the endogenously produced hydrogen sulfide with negligible interference from other biothiols in live cells. The excellent sensing properties of the probe combined with its capability of bioimaging thus make it a practically useful tool for further studying biological roles of hydrogen sulfide.

  6. Evaluation of cerium doped tin oxide nanoparticles as a sensitive sensor for selective detection and extraction of cobalt

    NASA Astrophysics Data System (ADS)

    Khan, Sher Bahadar; Asiri, Abdullah M.; Rahman, Mohammed M.; Marwani, Hadi M.; Alamry, Khalid A.

    2015-06-01

    Chemo-sensor technology demands to design a single, preconcentrator based sensing system having higher sensitivity, sufficient selectivity and efficient removal of metal ions with simple operating and recognition methodology. Here we effectively deliberated Ce doped SnO2 nanoparticles based sensing system which can be exploited for the recognition and extraction of Co(II) ions in a single step by strong interaction between Ce doped SnO2 nanoparticles and Co(II). The sensing ability of Ce doped SnO2 nanoparticles were deliberated for a selective removal of cobalt using inductively coupled plasma-optical emission spectrometry. The sensing ability of Ce doped SnO2 is studied for various metal ions, such as Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Ni(II) and Zn(II) but the designed sensor was most selective toward Co(II) which was 5000 time more sensitive to Co(II) rather than different interfering metal ions. In addition, the desorption study for regeneration of Ce doped SnO2 nanoparticles was carried out. This novel approach provides a new route for simultaneous detection and removal of Co(II) in a single step and can be a time and cost alternative tool for environmental safety.

  7. RNA aptamer based electrochemical biosensor for sensitive and selective detection of cAMP.

    PubMed

    Zhao, Fulin; Xie, Qingyun; Xu, Mingfei; Wang, Shouyu; Zhou, Jiyong; Liu, Fei

    2015-04-15

    Cyclic adenosine monophosphate (cAMP) is an important small biological molecule associated with the healthy state of living organism. In order to realize highly sensitive and specific detection of cAMP, here an RNA aptamer and electrochemical impedance spectroscopy (EIS) based biosensor enhanced by gold nanoparticles electrodeposited on the surface of gold electrode is designed. The designed aptasensor has a wide effective measuring range from 50pM to 250pM with a detection limit of 50pM in PBS buffer, and an effective measuring range from 50nM to 1μM with a detection limit of 50nM in serum. The designed biosensor is also able to detect cAMP with high sensitivity, specificity, and stability. Since the biosensor can be easily fabricated with low cost and repeatedly used for at least two times, it owns great potential in wide application fields such as clinical test and food inspection, etc.

  8. USP11-dependent selective cIAP2 deubiquitylation and stabilization determine sensitivity to Smac mimetics

    PubMed Central

    Lee, E-W; Seong, D; Seo, J; Jeong, M; Lee, H-K; Song, J

    2015-01-01

    Given their crucial role in apoptosis suppression, inhibitor of apoptosis proteins (IAPs) have recently become attractive targets for cancer therapy. Here, we report that cellular IAP2 (cIAP2) is specifically stabilized in several cancer cell lines, leading to resistance to Smac mimetics, such as BV6 and birinapant. In particular, our results showed that cIAP2 depletion, but not cIAP1 depletion, sensitized cancer cells to Smac mimetic-induced apoptosis. Ubiquitin-specific protease 11 (USP11) is a deubiquitylase that directly stabilizes cIAP2. USP11 overexpression is frequently found in colorectal cancer and melanoma and is correlated with poor survival. In our study, cancer cell lines expressing high levels of USP11 exhibited strong resistance to Smac mimetic-induced cIAP2 degradation. Furthermore, USP11 downregulation sensitized these cells to apoptosis induced by TRAIL and BV6 and suppressed tumor growth in a xenograft model. Finally, the TNFα/JNK pathway induced USP11 expression and maintained cIAP2 stability, suggesting an alternative TNFα-dependent cell survival pathway. Collectively, our data suggest that USP11-stabilized cIAP2 may serve as a barrier against IAP-targeted clinical approaches. PMID:25613375

  9. Electrosprayed Metal Oxide Semiconductor Films for Sensitive and Selective Detection of Hydrogen Sulfide

    PubMed Central

    Ghimbeu, Camelia Matei; Lumbreras, Martine; Schoonman, Joop; Siadat, Maryam

    2009-01-01

    Semiconductor metal oxide films of copper-doped tin oxide (Cu-SnO2), tungsten oxide (WO3) and indium oxide (In2O3) were deposited on a platinum coated alumina substrate employing the electrostatic spray deposition technique (ESD). The morphology studied with scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows porous homogeneous films comprising uniformly distributed aggregates of nano particles. The X-ray diffraction technique (XRD) proves the formation of crystalline phases with no impurities. Besides, the Raman cartographies provided information about the structural homogeneity. Some of the films are highly sensitive to low concentrations of H2S (10 ppm) at low operating temperatures (100 and 200 °C) and the best response in terms of Rair/Rgas is given by Cu-SnO2 films (2500) followed by WO3 (1200) and In2O3 (75). Moreover, all the films exhibit no cross-sensitivity to other reducing (SO2) or oxidizing (NO2) gases. PMID:22291557

  10. Electrosprayed metal oxide semiconductor films for sensitive and selective detection of hydrogen sulfide.

    PubMed

    Ghimbeu, Camelia Matei; Lumbreras, Martine; Schoonman, Joop; Siadat, Maryam

    2009-01-01

    Semiconductor metal oxide films of copper-doped tin oxide (Cu-SnO(2)), tungsten oxide (WO(3)) and indium oxide (In(2)O(3)) were deposited on a platinum coated alumina substrate employing the electrostatic spray deposition technique (ESD). The morphology studied with scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows porous homogeneous films comprising uniformly distributed aggregates of nano particles. The X-ray diffraction technique (XRD) proves the formation of crystalline phases with no impurities. Besides, the Raman cartographies provided information about the structural homogeneity. Some of the films are highly sensitive to low concentrations of H(2)S (10 ppm) at low operating temperatures (100 and 200 °C) and the best response in terms of R(air)/R(gas) is given by Cu-SnO(2) films (2500) followed by WO(3) (1200) and In(2)O(3) (75). Moreover, all the films exhibit no cross-sensitivity to other reducing (SO(2)) or oxidizing (NO(2)) gases.

  11. A highly sensitive and selective diagnostic assay based on virus nanoparticles

    NASA Astrophysics Data System (ADS)

    Park, Jin-Seung; Cho, Moon Kyu; Lee, Eun Jung; Ahn, Keum-Young; Lee, Kyung Eun; Jung, Jae Hun; Cho, Yunjung; Han, Sung-Sik; Kim, Young Keun; Lee, Jeewon

    2009-04-01

    Early detection of the protein marker troponin I in patients with a higher risk of acute myocardial infarction can reduce the risk of death from heart attacks. Most troponin assays are currently based on the conventional enzyme linked immunosorbent assay and have detection limits in the nano- and picomolar range. Here, we show that by combining viral nanoparticles, which are engineered to have dual affinity for troponin antibodies and nickel, with three-dimensional nanostructures including nickel nanohairs, we can detect troponin levels in human serum samples that are six to seven orders of magnitude lower than those detectable using conventional enzyme linked immunosorbent assays. The viral nanoparticle helps to orient the antibodies for maximum capture of the troponin markers. High densities of antibodies on the surfaces of the nanoparticles and nanohairs lead to greater binding of the troponin markers, which significantly enhances detection sensitivities. The nickel nanohairs are re-useable and can reproducibly differentiate healthy serum from unhealthy ones. We expect other viral nanoparticles to form similar highly sensitive diagnostic assays for a variety of other protein markers.

  12. Ion imprinted polymeric nanoparticles for selective separation and sensitive determination of zinc ions in different matrices.

    PubMed

    Shamsipur, Mojtaba; Rajabi, Hamid Reza; Pourmortazavi, Seied Mahdi; Roushani, Mahmoud

    2014-01-03

    Preparation of Zn(2+) ion-imprinted polymer (Zn-IIP) nanoparticles is presented in this report. The Zn-IIP nanoparticles are prepared by dissolving stoichiometric amounts of zinc nitrate and selected chelating ligand, 3,5,7,20,40-pentahydroxyflavone, in 15 mL ethanol-acetonitrile (2:1; v/v) mixture as a porogen solvent in the presence of ethylene glycol-dimethacrylate (EGDMA) as cross-linking, methacrylic acid (MAA) as functional monomer, and 2,2-azobisisobutyronitrile (AIBN) as initiator. After polymerization, Cavities in the polymer particles corresponding to the Zn(2+) ions were created by leaching the polymer in HCl aqueous solution. The synthesized IIPs were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, fluorescence spectroscopy and thermal analysis techniques. Also, the pH range for rebinding of Zn(2+) ion on the IIP and equilibrium binding time were optimized, using flame atomic absorption spectrometry. In selectivity study, it was found that imprinting results increased affinity of the material toward Zn(2+) ion over other competitor metal ions with the same charge and close ionic radius. The prepared IIPs were repeatedly used and regenerated for six times without any significant decrease in polymer binding affinities. Finally, the prepared sorbent was successfully applied to the selective recognition and determination of zinc ion in different real samples.

  13. The effects of daily-wear contact lenses on contrast sensitivity in selected professional and collegiate female tennis players.

    PubMed

    Kluka, D A; Love, P A

    1993-03-01

    Contrast sensitivity (CS) has recently emerged as an important predictor of visual performance. Few studies, however, have been published involving CS and its role in vision for sport. The purpose of this investigation was to determine if significant differences occurred in CS between female professional and collegiate tennis players who wore daily-wear soft contact lenses (N = 10) and those players who wore no corrective lenses (N = 10) in competition as measured by the Stereo Optical Optec 2000 Vision Tester. Subjects were between the ages of 18 and 37 years. Mean ages were 21.76 (+/- 4.018) and 25.40 (+/- 5.379) years for those wearing lenses and those not, respectively. Each subject was preliminarily screened for SVA-distance, lateral/vertical phorias, stereopsis, and color perception. All subjects were within accepted limits. CS was assessed at 1.5, 3, 6, 12, and 18 cycles per degree (cpd). Each subject was assessed monocularly; eye initially assessed was determined randomly. A 2 x 2 factorial analysis of variance (alpha = .05) was used to analyze data. No significant differences were found between eyes. Significant differences were found at 3, 6, 12, and 18 cpd. It may be concluded that those female professional and collegiate tennis players wearing no corrective lenses were significantly higher in CS at intermittent and high spatial frequencies than those who wore daily-wear soft contact lenses in competition.

  14. Boronic acid functionalized N-doped carbon quantum dots as fluorescent probe for selective and sensitive glucose determination

    NASA Astrophysics Data System (ADS)

    Jiang, Guohua; Jiang, Tengteng; Li, Xia; Wei, Zheng; Du, Xiangxiang; Wang, Xiaohong

    2014-04-01

    Nitrogen doped carbon quantum dots (NCQDs) of about 10 nm in diameter have been obtained by hydrothermal reaction from collagen. Because of the superiority of water dispersion, low toxicity and ease of functionlization, the NCQDs were designed as a glucose sensor after covalent grafting by 3-aminophenylboronic (APBA) (APBA-NCQDs). The as-prepared APBA-NCQDs were imparted with glucose sensitivity and selectivity from other saccharides via fluorescence (FL) quenching effect at physiological pH and at room temperature, which show high sensitivity and specificity for glucose determination with a wide range from 1 mM to 14 mM. FL quenching mechanism of APBA-NCQDs was also investigated by adding an external quencher. The APBA-NCQDs-based platform is an environmentally friendly way to substitute inorganic quantum dots containing heavy metals which offer a facile and low cost detection method.

  15. Disperse fine equiaxed alpha alumina nanoparticles with narrow size distribution synthesised by selective corrosion and coagulation separation

    PubMed Central

    Pu, Sanxu; Li, Lu; Ma, Ji; Lu, Fuliang; Li, Jiangong

    2015-01-01

    Disperse fine equiaxed α-Al2O3 nanoparticles with narrow size distribution are important materials in nanotechnology and nanomaterials, but syntheses of disperse fine equiaxed α-Al2O3 nanoparticles usually result in fine γ-Al2O3 nanoparticles or large α-Al2O3 nanoparticles larger than 15 nm. α-Al2O3 has a higher surface energy than γ-Al2O3 and becomes thermodynamically not stable with respect to γ-Al2O3 at specific surface areas larger than 100 m2/g (at sizes smaller than 15 nm for spherical particles) at room temperature. So disperse fine equiaxed α-Al2O3 nanoparticles smaller than 15 nm with narrow size distribution are extremely difficult to synthesise. Here we show the successful synthesis of disperse fine equiaxed α-Al2O3 nanoparticles with average sizes below 10 nm and narrow size distribution by selective corrosion and refined fractionated coagulation separation. An almost fully dense nanocrystalline α-Al2O3 ceramic with a relative density of 99.5% and an average grain size of 60 nm can be sintered from disperse fine equiaxed α-Al2O3 nanoparticles with narrow size distribution. PMID:26166455

  16. Recent approaches to improving selectivity and sensitivity of enzyme-based biosensors for organophosphorus pesticides: A review.

    PubMed

    Songa, Everlyne A; Okonkwo, Jonathan O

    2016-08-01

    Pesticide determination has attracted great attention due to the fact that they exhibit high acute toxicity and can cause long-term damage to the environment and human lives even at trace levels. Although classical analytical methods (including gas chromatography, high performance liquid chromatography, capillary electrophoresis and mass spectrometry) have been effectively used for analysis of pesticides in contaminated samples, they present certain limitations such as time-consuming sample preparation, complexity, and the requirement of expensive instrumentation and highly skilled personnel. For these reasons, there is an expanding need for analytical methods able to provide simple, rapid, sensitive, selective, low cost and reliable detection of pesticides at trace levels. Over the past decades, acetylcholinesterase (AChE) biosensors have emerged as simple, rapid and ultra-sensitive tools for toxicity detection of pesticides in the environment and food. These biosensors have the potential to complement or replace the classical analytical methods by simplifying or eliminating sample preparation and making field-testing easier and faster with significant decrease in cost per analysis. With the recent engineering of more sensitive AChE enzymes, the development of more reliable immobilization matrices and the progress in the area of microelectronics, AChE biosensors could become competitive for multi-analyte screening and soon be used for the development of portable instrumentation for rapid toxicity testing of samples. The enzymes organophosphorus hydrolase (OPH) and organophosphorus acid anhydrolase (OPAA) have also shown considerable potential in OP biosensor applications and they have been used for direct detection of OPs. This review presents the recent advances in the fabrication of enzyme biosensors for organophosphorus pesticides (OPs) and their possible applications for toxicity monitoring of organophosphorus pesticide residues in real samples. The focus will

  17. Intermittent Preventive Treatment with Dihydroartemisinin-Piperaquine in Ugandan Schoolchildren Selects for Plasmodium falciparum Transporter Polymorphisms That Modify Drug Sensitivity

    PubMed Central

    Conrad, Melissa D.; Legac, Jennifer; Tukwasibwe, Stephen; Tumwebaze, Patrick; Wandera, Bonnie; Brooker, Simon J.; Staedke, Sarah G.; Kamya, Moses R.; Nsobya, Sam L.; Dorsey, Grant; Rosenthal, Philip J.

    2016-01-01

    Dihydroartemisinin-piperaquine (DP) offers prolonged protection against malaria, but its impact on Plasmodium falciparum drug sensitivity is uncertain. In a trial of intermittent preventive treatment in schoolchildren in Tororo, Uganda, in 2011 to 2012, monthly DP for 1 year decreased the incidence of malaria by 96% compared to placebo; DP once per school term offered protection primarily during the first month after therapy. To assess the impact of DP on selection of drug resistance, we compared the prevalence of key polymorphisms in isolates that emerged at different intervals after treatment with DP. Blood obtained monthly and at each episode of fever was assessed for P. falciparum parasitemia by microscopy. Samples from 160 symptomatic and 650 asymptomatic episodes of parasitemia were assessed at 4 loci (N86Y, Y184F, and D1246Y in pfmdr1 and K76T in pfcrt) that modulate sensitivity to aminoquinoline antimalarials, utilizing a ligase detection reaction-fluorescent microsphere assay. For pfmdr1 N86Y and pfcrt K76T, but not the other studied polymorphisms, the prevalences of mutant genotypes were significantly greater in children who had received DP within the past 30 days than in those not treated within 60 days (86Y, 18.0% versus 8.3% [P = 0.03]; 76T, 96.0% versus 86.1% [P = 0.05]), suggesting selective pressure of DP. Full sequencing of pfcrt in a subset of samples did not identify additional polymorphisms selected by DP. In summary, parasites that emerged soon after treatment with DP were more likely than parasites not under drug pressure to harbor pfmdr1 and pfcrt polymorphisms associated with decreased sensitivity to aminoquinoline antimalarials. (This study has been registered at ClinicalTrials.gov under no. NCT01231880.) PMID:27401569

  18. HST Emission Line Galaxies at z ~ 2: Comparing Physical Properties of Lyman Alpha and Optical Emission Line Selected Galaxies

    NASA Astrophysics Data System (ADS)

    Hagen, Alex; Zeimann, Gregory R.; Behrens, Christoph; Ciardullo, Robin; Grasshorn Gebhardt, Henry S.; Gronwall, Caryl; Bridge, Joanna S.; Fox, Derek B.; Schneider, Donald P.; Trump, Jonathan R.; Blanc, Guillermo A.; Chiang, Yi-Kuan; Chonis, Taylor S.; Finkelstein, Steven L.; Hill, Gary J.; Jogee, Shardha; Gawiser, Eric

    2016-01-01

    We compare the physical and morphological properties of z ˜ 2 Lyα emitting galaxies (LAEs) identified in the HETDEX Pilot Survey and narrow band studies with those of z ˜ 2 optical emission line selected galaxies (oELGs) identified via HST WFC3 infrared grism spectroscopy. Both sets of galaxies extend over the same range in stellar mass (7.5\\lt {log}M/{M}⊙ \\lt 10.5), size (0.5 < R < 3.0 kpc), and star formation rate (˜ 1\\lt {{SFR}}\\lt 100 {M}⊙ yr-1). Remarkably, a comparison of the most commonly used physical and morphological parameters—stellar mass, half-light radius, UV slope, SFR, ellipticity, nearest neighbor distance, star formation surface density, specific SFR, [O iii] luminosity, and [O iii] equivalent width—reveals no statistically significant differences between the populations. This suggests that the processes and conditions which regulate the escape of Lyα from a z ˜ 2 star-forming galaxy do not depend on these quantities. In particular, the lack of dependence on the UV slope suggests that Lyα emission is not being significantly modulated by diffuse dust in the interstellar medium. We develop a simple model of Lyα emission that connects LAEs to all high-redshift star-forming galaxies where the escape of Lyα depends on the sightline through the galaxy. Using this model, we find that mean solid angle for Lyα escape is {{{Ω }}}{{Ly}α }=2.4+/- 0.8 steradians; this value is consistent with those calculated from other studies.

  19. Highly selective and sensitive fluorescence chemosensor for the detection of palladium species based on Tsuji-Trost reaction.

    PubMed

    Xu, Zhong-Yong; Li, Jing; Guan, Su; Zhang, Lei; Dong, Chang-Zhi

    2015-09-05

    A new chemosensor 7-nitro-2,1,3-benzoxadiazole-4-allyl-N-(thiophen-2-ylmethyl)carbamate (NBDTC) was synthesized and utilized for palladium detection based on the Tsuji-Trost reaction. NBDTC displayed specific and ratiometric fluorescent responses toward palladium species. The chemosensor showed more than 50-fold enhancement in fluorescence intensity with the presence of PEG400 and palladium because NBDTC can be transformed to NBDT under palladium-catalyzing Tsuji-Trost reaction. NBDTC displayed high selectivity and sensitivity for palladium species with the detection limit of 1.13×10(-9) M.

  20. Rhodamine 6G hydrazone bearing thiophene unit: A highly sensitive and selective off-on fluorescent chemosensor for Al3+

    NASA Astrophysics Data System (ADS)

    Wu, Wei-Na; Mao, Pan-Dong; Wang, Yuan; Zhao, Xiao-Lei; Jia, Lei; Xu, Zhou-Qing

    2016-10-01

    A rhodamine derivative (R1) has been synthesized by a hydrazone formation of rhodamine 6G hydrazide with 3-methylthiophene-2-carbaldehyde, which exhibits high selectivity and sensitivity as an "off-on" fluorescent sensor toward Al3+ in water containing media. The binding process was confirmed by UV-vis absorption, fluorescence measurements, mass spectroscopy and DFT calculation. The probe functions by Al3+ induced hydrolytic cleavage of the imine-bond to produce an intense rhodamine-based emission. To test the practical use of the probe, the determination of Al3+ in real water samples was also evaluated.

  1. Selective and sensitive spectrophotometric method for determination of sub-micro-molar amounts of aluminium ion.

    PubMed

    Shokrollahi, A; Ghaedi, M; Niband, M S; Rajabi, H R

    2008-03-01

    A simple and accurate spectrophotometric method for determination of trace and ultra-trace amounts of Al3+ ion in tap and wastewater sample has been described. Using the eriochrome cyanine R (ECR) in the presence of N,N-dodecyltrimethylammonium bromide (DTAB) as cationic surfactant spectrophotometric determination of Al3+ ion has been carried out. The Beer's law is obeyed over the concentration range of 4-400 ng mL(-1) of Al3+ ion with the detection limits of 0.14 ng mL(-1), while the molar absorptivity of complexes is 1.19x10(5) L mol(-1) cm(-1). The influence of type and amount of surfactant, pH, and amount of ligand on sensitivity of spectrophotometric method were optimized. The method has been successfully applied for Al3+ ion determination in real sample.

  2. Oncogene-Selective Sensitivity to Synchronous Cell Death following Modulation of the Amino Acid Nutrient Cystine.

    PubMed

    Poursaitidis, Ioannis; Wang, Xiaomeng; Crighton, Thomas; Labuschagne, Christiaan; Mason, David; Cramer, Shira L; Triplett, Kendra; Roy, Rajat; Pardo, Olivier E; Seckl, Michael J; Rowlinson, Scott W; Stone, Everett; Lamb, Richard F

    2017-03-14

    Cancer cells reprogram their metabolism, altering both uptake and utilization of extracellular nutrients. We individually depleted amino acid nutrients from isogenic cells expressing commonly activated oncogenes to identify correspondences between nutrient supply and viability. In HME (human mammary epithelial) cells, deprivation of cystine led to increased cell death in cells expressing an activated epidermal growth factor receptor (EGFR) mutant. Cell death occurred via synchronous ferroptosis, with generation of reactive oxygen species (ROS). Hydrogen peroxide promoted cell death, as both catalase and inhibition of NADPH oxidase 4 (NOX4) blocked ferroptosis. Blockade of EGFR or mitogen-activated protein kinase (MAPK) signaling similarly protected cells from ferroptosis, whereas treatment of xenografts derived from EGFR mutant non-small-cell lung cancer (NSCLC) with a cystine-depleting enzyme inhibited tumor growth in mice. Collectively, our results identify a potentially exploitable sensitization of some EGFR/MAPK-driven tumors to ferroptosis following cystine depletion.

  3. An electrochemical impedimetric aptasensing platform for sensitive and selective detection of small molecules such as chloramphenicol.

    PubMed

    Pilehvar, Sanaz; Dierckx, Tarryn; Blust, Ronny; Breugelmans, Tom; De Wael, Karolien

    2014-07-07

    We report on the aptadetection of chloramphenicol (CAP) using electrochemical impedance spectroscopy. The detection principle is based on the changes of the interfacial properties of the electrode after the interaction of the ssDNA aptamers with the target molecules. The electrode surface is partially blocked due to the formation of the aptamer-CAP complex, resulting in an increase of the interfacial electron-transfer resistance of the redox probe detected by electrochemical impedance spectroscopy or cyclic voltammetry. We observed that the ratio of polarization resistance had a linear relationship with the concentrations of CAP in the range of 1.76-127 nM, and a detection limit of 1.76 nM was obtained. The covalent binding of CAP-aptamer on the electrode surface combined with the unique properties of aptamers and impedimetric transduction leads to the development of a stable and sensitive electrochemical aptasensor for CAP.

  4. Highly selective and sensitive nucleic acid detection based on polysaccharide-functionalized silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Yan, Jing-Kun; Ma, Hai-Le; Cai, Pan-Fu; Wu, Jian-Yong

    2015-01-01

    Polysaccharide-functionalized silver nanoparticles (Oc-AgNPs) with a mean diameter of 15 nm were utilized as a novel and effective fluorescence-sensing platform for nucleic acid detection. Tests on the oligonucleotide sequences associated with the human immunodeficiency virus as a model system showed that the Oc-AgNPs effectively absorbed and quenched dye-labeled single-stranded DNA through strong hydrogen bonding interactions and slight electrostatic attractive interactions. The proposed system efficiently differentiated between complementary and mismatched nucleic acid sequences with high selectivity and good reproducibility at room temperature.

  5. Highly selective and sensitive nucleic acid detection based on polysaccharide-functionalized silver nanoparticles.

    PubMed

    Yan, Jing-Kun; Ma, Hai-Le; Cai, Pan-Fu; Wu, Jian-Yong

    2015-01-05

    Polysaccharide-functionalized silver nanoparticles (Oc-AgNPs) with a mean diameter of 15 nm were utilized as a novel and effective fluorescence-sensing platform for nucleic acid detection. Tests on the oligonucleotide sequences associated with the human immunodeficiency virus as a model system showed that the Oc-AgNPs effectively absorbed and quenched dye-labeled single-stranded DNA through strong hydrogen bonding interactions and slight electrostatic attractive interactions. The proposed system efficiently differentiated between complementary and mismatched nucleic acid sequences with high selectivity and good reproducibility at room temperature.

  6. Tailoring dye-sensitized upconversion nanoparticle excitation bands towards excitation wavelength selective imaging

    DOE PAGES

    Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; ...

    2015-01-01

    One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. Finally, this work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs.

  7. Highly sensitive and selective fluoride detection in water through fluorophore release from a metal-organic framework.

    PubMed

    Hinterholzinger, Florian M; Rühle, Bastian; Wuttke, Stefan; Karaghiosoff, Konstantin; Bein, Thomas

    2013-01-01

    The detection, differentiation and visualization of compounds such as gases, liquids or ions are key challenges for the design of selective optical chemosensors. Optical chemical sensors employ a transduction mechanism that converts a specific analyte recognition event into an optical signal. Here we report a novel concept for fluoride ion sensing where a porous crystalline framework serves as a host for a fluorescent reporter molecule. The detection is based on the decomposition of the host scaffold which induces the release of the fluorescent dye molecule. Specifically, the hybrid composite of the metal-organic framework NH2-MIL-101(Al) and fluorescein acting as reporter shows an exceptional turn-on fluorescence in aqueous fluoride-containing solutions. Using this novel strategy, the optical detection of fluoride is extremely sensitive and highly selective in the presence of many other anions.

  8. Heterometal-organic frameworks as highly sensitive and highly selective luminescent probes to detect I⁻ ions in aqueous solutions.

    PubMed

    Shi, Peng-Fei; Hu, Huan-Cheng; Zhang, Zhan-Yun; Xiong, Gang; Zhao, Bin

    2015-03-07

    Two cationic heterometal-organic frameworks (Eu-Zn (1·NO₃⁻) and Tb-Zn (2·NO₃⁻)) with NO3(-) counter-anions in the channels are structurally and luminously characterized. Both of them can serve as highly sensitive and highly selective luminescent probes for detecting I(-) ions in aqueous solutions. In particular, 2·NO₃⁻ can selectively and reversibly detect I(-) with a fast response time of just 10 s and an extremely low detection limit of 0.001 ppm. Mechanism studies reveal that I(-) is quickly oxidized to form I₃⁻with the help of 1·NO₃⁻ or 2·NO₃⁻, leading to luminescence quenching. This represents the first report of MOF-based luminescent probes for the detection of I(-) in aqueous solutions.

  9. A sensitive and selective resonance Rayleigh scattering method for quick detection of avidin using affinity labeling Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Huang, Xi; Fu, Xuan; Deng, Huan; Ma, Meihu; Cai, Zhaoxia

    2016-06-01

    Avidin is a glycoprotein with antinutritional property, which should be limited in daily food. We developed an affinity biosensor system based on resonance Rayleigh scattering (RRS) and using affinity biotin labeling Au nanoparticles (AuNPs). This method was selective and sensitive for quick avidin detection due to the avidin-biotin affinitive interaction. Under optimal conditions, RRS intensity of biotin-AuNPs increase linearly with an increasing concentration of avidin from 5 to 160 ng/mL. The lower limit of detection was 0.59 ng/mL. This rapid and selective avidin detection method was used in synthetic samples and egg products with recoveries of between 102.97 and 107.92%, thereby demonstrating the feasible and practical application of this assay.

  10. A sensitive and selective resonance Rayleigh scattering method for quick detection of avidin using affinity labeling Au nanoparticles.

    PubMed

    Wang, Qi; Huang, Xi; Fu, Xuan; Deng, Huan; Ma, Meihu; Cai, Zhaoxia

    2016-06-05

    Avidin is a glycoprotein with antinutritional property, which should be limited in daily food. We developed an affinity biosensor system based on resonance Rayleigh scattering (RRS) and using affinity biotin labeling Au nanoparticles (AuNPs). This method was selective and sensitive for quick avidin detection due to the avidin-biotin affinitive interaction. Under optimal conditions, RRS intensity of biotin-AuNPs increase linearly with an increasing concentration of avidin from 5 to 160 ng/mL. The lower limit of detection was 0.59 ng/mL. This rapid and selective avidin detection method was used in synthetic samples and egg products with recoveries of between 102.97 and 107.92%, thereby demonstrating the feasible and practical application of this assay.

  11. Audit Report on "Management Controls over the Department's Excess Weapons Inventories and Selected Sensitive Equipment used by Protective Forces"

    SciTech Connect

    2009-01-01

    Since September 11, 2001, the Department of Energy has, on several occasions, revised its security posture based on identified threats and adversaries. These revisions in security posture have driven Departmental sites to upgrade their defensive and tactical equipment. Subsequent changes in the perceived threats have, in some cases, led to a reduction in the need for certain types of weapons, thus creating a pool of surplus equipment. These surplus weapons could potentially be used by other Department sites and Federal law enforcement agencies. Recent Office of Inspector General reports have raised concerns with the adequacy of controls related to defensive and tactical equipment. For example, our report on Management Controls Over Defense Related High Risk Property (OAS-M-08-06, April 2008) found that administrative controls over certain defense related high risk property were not sufficient for providing accountability over these items. Because of prior reported weaknesses in controls over defensive and tactical equipment, we initiated this audit to determine whether the Department and its contractors were properly managing excess weapons inventories and selected sensitive equipment used by protective forces. Our review disclosed that the Department was not always properly managing its inventories of excess weapons and selected sensitive equipment. We identified issues with the retention of unneeded weapons at many locations and with the identification and tracking of sensitive items. More specifically: Sites maintained large inventories of weapons that were no longer needed but had not been made available for use by either other Departmental sites or other Federal law enforcement agencies. For instance, at six of the locations included in our review we identified a total of 2,635 unneeded weapons with a total acquisition value of over $2.8 million that had not been officially declared as excess - an action that would have made them available for others to use

  12. Molecularly imprinted polymer decorated nanoporous gold for highly selective and sensitive electrochemical sensors

    PubMed Central

    Li, Yingchun; Liu, Yuan; Liu, Jie; Liu, Jiang; Tang, Hui; Cao, Cong; Zhao, Dongsheng; Ding, Yi

    2015-01-01

    Electrochemical nanosensors based on nanoporous gold leaf (NPGL) and molecularly imprinted polymer (MIP) are developed for pharmaceutical analysis by using metronidazole (MNZ) as a model analyte. NPGL, serving as the loading platform for MIP immobilization, possesses large accessible surface area with superb electric conductivity, while electrochemically synthesized MIP thin layer affords selectivity for specific recognition of MNZ molecules. For MNZ determination, the hybrid electrode shows two dynamic linear range of 5 × 10−11 to 1 × 10−9 mol L−1 and 1 × 10−9 to 1.4 × 10−6 mol L−1 with a remarkably low detection limit of 1.8 × 10−11 mol L−1 (S/N = 3). In addition, the sensor exhibits high binding affinity and selectivity towards MNZ with excellent reproducibility and stability. Finally, the reliability of MIP-NPGL for MNZ detection is proved in real fish tissue samples, demonstrating the potential for the proposed electrochemical sensors in monitoring drug and biological samples. PMID:25572290

  13. Estimating Premium Sensitivity for Children's Public Health Insurance Coverage: Selection but No Death Spiral

    PubMed Central

    Marton, James; Ketsche, Patricia G; Snyder, Angela; Adams, E Kathleen; Zhou, Mei

    2015-01-01

    Objective To estimate the effect of premium increases on the probability that near-poor and moderate-income children disenroll from public coverage. Data Sources Enrollment, eligibility, and claims data for Georgia's PeachCare for Kids™ (CHIP) program for multiple years. Study Design We exploited policy-induced variation in premiums generated by cross-sectional differences and changes over time in enrollee age, family size, and income to estimate the duration of enrollment as a function of the effective (per child) premium. We classify children as being of low, medium, or high illness severity. Principal Findings A dollar increase in the per-child premium is associated with a slight increase in a typical child's monthly probability of exiting coverage from 7.70 to 7.83 percent. Children with low illness severity have a significantly higher monthly baseline probability of exiting than children with medium or high illness severity, but the enrollment response to premium increases is similar across all three groups. Conclusions Success in achieving coverage gains through public programs is tempered by persistent problems in maintaining enrollment, which is modestly affected by premium increases. Retention is subject to adverse selection problems, but premium increases do not appear to significantly magnify the selection problem in this case. PMID:25130764

  14. Molecularly imprinted polymer decorated nanoporous gold for highly selective and sensitive electrochemical sensors

    NASA Astrophysics Data System (ADS)

    Li, Yingchun; Liu, Yuan; Liu, Jie; Liu, Jiang; Tang, Hui; Cao, Cong; Zhao, Dongsheng; Ding, Yi

    2015-01-01

    Electrochemical nanosensors based on nanoporous gold leaf (NPGL) and molecularly imprinted polymer (MIP) are developed for pharmaceutical analysis by using metronidazole (MNZ) as a model analyte. NPGL, serving as the loading platform for MIP immobilization, possesses large accessible surface area with superb electric conductivity, while electrochemically synthesized MIP thin layer affords selectivity for specific recognition of MNZ molecules. For MNZ determination, the hybrid electrode shows two dynamic linear range of 5 × 10-11 to 1 × 10-9 mol L-1 and 1 × 10-9 to 1.4 × 10-6 mol L-1 with a remarkably low detection limit of 1.8 × 10-11 mol L-1 (S/N = 3). In addition, the sensor exhibits high binding affinity and selectivity towards MNZ with excellent reproducibility and stability. Finally, the reliability of MIP-NPGL for MNZ detection is proved in real fish tissue samples, demonstrating the potential for the proposed electrochemical sensors in monitoring drug and biological samples.

  15. Prevalence of -alpha(3.7) and alpha alpha alpha(anti3.7) alleles in sickle cell trait and beta-thalassemia patients in Mexico.

    PubMed

    Nava, María Paulina; Ibarra, Bertha; Magaña, María Teresa; de la Luz Chávez, María; Perea, F Javier

    2006-01-01

    The aim of this study was to determine the frequency of alpha-globin gene mutations in three groups of Mexican unrelated individuals. The first two groups were normal and sickle cell trait individuals from the Costa Chica region, a place with a 12.8% frequency of HbS carriers, and the third group comprised of Mexican mestizo patients with beta-thalassemia. We searched for -alpha(3.7) and -alpha(4.2) alpha(+)-thalassemia deletion alleles, as well as the alpha alpha alpha(anti3.7) triplication through long-gap PCR. The alleles -alpha(3.7) and alpha alpha alpha(anti3.7) were found in the heterozygote state only; 19% of the normal subjects had the -alpha(3.7) allele, and 2% showed the alpha alpha alpha(anti3.7) allele. In individuals with the sickle cell trait, 17% had the -alpha(3.7) deletion, and the alpha alpha alpha(anti3.7) triplication was observed in 3% of these individuals. We revealed that 16% of the subjects with beta-thalassemia showed the -alpha(3.7) deletion and 28% the alpha alpha alpha(anti3.7) triplication. The -alpha(4.2) deletion was not detected in any individual. The frequency of the -alpha(3.7) allele was roughly the same in the three groups studied; this can be explained by the fact that the three groups have common genes from Africa and the Mediterranean, where a high prevalence of alpha(+)-thalassemia has been observed. To our knowledge, the frequency of alpha alpha alpha(anti3.7) triplication observed in the Mexican beta-thalassemia patients is the highest reported. As the -alpha(3.7) and alpha alpha alpha(anti3.7) alleles are very common in our selected populations, we believe that there is a need to investigate systematically the alpha-globin gene mutations in all hemoglobinopathies in the Mexican population.

  16. A carbon dot-based "off-on" fluorescent probe for highly selective and sensitive detection of phytic acid.

    PubMed

    Gao, Zhao; Wang, Libing; Su, Rongxin; Huang, Renliang; Qi, Wei; He, Zhimin

    2015-08-15

    We herein report a facile, one-step pyrolysis synthesis of photoluminescent carbon dots (CDs) using citric acid as the carbon source and lysine as the surface passivation reagent. The as-prepared CDs show narrow size distribution, excellent blue fluorescence and good photo-stability and water dispersivity. The fluorescence of the CDs was found to be effectively quenched by ferric (Fe(III)) ions with high selectivity via a photo-induced electron transfer (PET) process. Upon addition of phytic acid (PA) to the CDs/Fe(III) complex dispersion, the fluorescence of the CDs was significantly recovered, arising from the release of Fe(III) ions from the CDs/Fe(III) complex because PA has a higher affinity for Fe(III) ions compared to CDs. Furthermore, we developed an "off-on" fluorescence assay method for the detection of phytic acid using CDs/Fe(III) as a fluorescent probe. This probe enables the selective detection of PA with a linear range of 0.68-18.69 μM and a limit of detection (signal-to-noise ratio is 3) of 0.36 μM. The assay method demonstrates high selectivity, repeatability, stability and recovery ratio in the detection of the standard and real PA samples. We believe that the facile operation, low-cost, high sensitivity and selectivity render this CD-based "off-on" fluorescent probe an ideal sensing platform for the detection of PA.

  17. Environmental sensitivity differs between rabbit lines selected for reproductive intensity and longevity.

    PubMed

    Savietto, D; Cervera, C; Blas, E; Baselga, M; Larsen, T; Friggens, N C; Pascual, J J

    2013-12-01

    To better understand the mechanisms that allow some animals to sustain their productive effort in harsh environmental conditions, rabbit does from two selection lines (LP and V) were housed in normal (NC), nutritional (NF) or heat (HC) challenging environmental conditions from first to third partum. The LP line (n=85) was founded on reproductive longevity criteria by selecting does from commercial farms that had a minimum of 25 partum with more than 7.5 kits born alive per parity. Line V (n=79) was constituted from four specialised maternal lines into a composite synthetic line and then selected by litter size at weaning for 36 generations. Female rabbits in NC and NF environments were housed at normal room temperature (18°C to 24°C) and fed with control [11.6 MJ digestible energy (DE)/kg dry matter (DM)] or low-energy diets (9.1 MJ DE/kg DM). HC does were housed at high room temperatures (25°C to 35°C) and fed the control diet. Female rabbits in the HC and NF environments ingested 11.5% and 6% less DE than NC does, respectively (P<0.05). These differences between environments occurred in both lines, with the differences being higher for LP than for V does (+6%; P<0.05). Milk yield responses followed those of energy intake also being higher for LP does (+21.3 g/day; P<0.05). The environmental conditions did not affect the perirenal fat thickness (PFT), but a genotype by environment interaction was observed. In NC and HC, the PFT was higher for line V (+0.23 and +0.35 mm, respectively; P<0.05) than for LP does, but this was not the case at NF (-0.01 mm). Moreover, the PFT evolution was different between them. In the NC environment, LP does used the accreted PFT in late lactation (-0.29 mm), whereas V does did not (-0.08 mm). Conversely, in the HC environment, LP does showed a flat PFT evolution in late lactation, whereas V does accumulated PFT. In the NF environment, LP and V does had a similar PFT evolution. There was also a litter size reduction for V does of

  18. Joint study on the teratogenic sensitivity of the Pika (Ochotona rufescens rufescens) to selected drugs.

    PubMed

    Nishimura, H; Shiota, K; Uwabe, C; Nomura, T

    1986-10-01

    A collaborative study was conducted to investigate the teratological susceptibility of the Pika (Ochotona rufescens rufescens) to selected teratogenic chemicals: cyclophosphamide, 6-mercaptopurine, 5-fluorouracil, 6-aminonicotinamide, actinomycin D, ethylurethan, ampicillin, tetracycline, thalidomide, diphenylhydantoin, hypervitaminosis A, aspirin, dexamethasone, betamethasone and bredinin. Some of the chemicals were shown to be teratogenic in the Pika, but this animal was generally more resistant to their teratogenicity than the rabbit and rodents. In the Pika, thalidomide did not induce any typical limb defects, which have been produced in the rabbit. Pikas reproduce well and appear to have no substantial disadvantages as an animal species for teratological studies. Thus, the Pika may be useful as a new non-rodent species for teratological testings.

  19. A femtosecond stimulated Raman loss (fSRL) microscope for highly sensitive bond-selective imaging

    NASA Astrophysics Data System (ADS)

    Zhang, Delong; Slipchenko, Mikhail N.; Yue, Shuhua; Li, Junjie; Cheng, Ji-Xin

    2011-03-01

    We demonstrate nonlinear vibrational imaging of isolated Raman bands by detecting femtosecond pulse stimulated Raman loss. Femtosecond pulse excitation produces a stimulated Raman loss signal that is 12 times larger than what picosecond pulse excitation produces. The strong signal allowed real-time, bond-selective imaging of deuterated palmitic acid-d31 inside live cells, and 3D sectioning of fat storage in live C. elegans. With the high peak power provided by femtosecond pulses, this system is highly compatible with other nonlinear optical modalities such as two-photon excited fluorescence. With most of the excitation power contributed by the Stokes beam in the 1.0 - 1.2 μm wavelength range, photodamage of biological samples was not observed.

  20. A rapid and sensitive method for gas chromatographic analysis of the selective piscicide, "Squaxon".

    PubMed

    Gabica, J; Benson, W W; Watson, M

    1976-02-01

    "Squaxon" (1,1'methylenedi- 2 napthol; bis (2 hydroxy-1- naphthyl) methane) was discovered by MacPhee and Ruelle (1968, 1969) to exhibit piscicidal properties that are highly species specific. The chemical is lethal to the Northern (Ptychocheilus oregonensis) and the Umpqua (P. umpquae) squawfish, freshwater cyprinids common to the Pacific Northwest, at water treatment concentrations of less than 100 parts per billion (ppb). Other species of fish, including the more desirable salmonids with which the squawfish competes ecologically, are unaffected until this dosage has been increased severalfold. Because squawfish are widely regarded as undesirable for food or sporting purposes, and because competition from squawfish has severely depleted salmonid populations in some areas (Thompson, 1959; Jeppson and Platts, 1959) the potential use of squaxon for fisheries improvement is quite obvious. Squaxon is currently being tested for this purpose on an experimental basis in selected areas in Idaho, Oregon, and Washington, pending federal clearance for more widespread application.

  1. Winning territorial disputes selectively enhances androgen sensitivity in neural pathways related to motivation and social aggression.

    PubMed

    Fuxjager, Matthew J; Forbes-Lorman, Robin M; Coss, Dylan J; Auger, Catherine J; Auger, Anthony P; Marler, Catherine A

    2010-07-06

    Winning aggressive disputes can enhance future fighting ability and the desire to seek out additional contests. In some instances, these effects are long lasting and vary in response to the physical location of a fight. Thus, in principle, winning aggressive encounters may cause long-term and context-dependent changes to brain areas that control the output of antagonistic behavior or the motivation to fight (or both). We examined this issue in the territorial California mouse (Peromyscus californicus) because males of this species are more likely to win fights after accruing victories in their home territory but not after accruing victories in unfamiliar locations. Using immunocytochemistry and real-time quantitative PCR, we found that winning fights either at home or away increases the expression of androgen receptors (AR) in the medial anterior bed nucleus of the stria terminalis, a key brain area that controls social aggression. We also found that AR expression in brain regions that mediate motivation and reward, nucleus accumbens (NAcc) and ventral tegmental area (VTA), increases only in response to fights in the home territory. These effects of winning were likely exclusive to the neural androgenic system because they have no detectible impact on the expression of progestin receptors. Finally, we demonstrated that the observed changes in androgen sensitivity in the NAcc and VTA are positively associated with the ability to win aggressive contests. Thus, winning fights can change brain phenotype in a manner that likely promotes future victory and possibly primes neural circuits that motivate individuals to fight.

  2. Based on magnetic graphene oxide highly sensitive and selective imprinted sensor for determination of sunset yellow.

    PubMed

    Li, Jianbo; Wang, Xiaojiao; Duan, Huimin; Wang, Yanhui; Bu, Yanan; Luo, Chuannan

    2016-01-15

    A new imprinted material based on β-cyclodextrin/ionic liquid/gold nanoparticles functionalized magnetic graphene oxide has been successfully synthesized and modified to the glassy carbon electrode surface to constructed imprinted electrochemical sensor to detect sunset yellow. The sensitivity and electrochemical response of the electrode can be improved by nanomaterials. The surface morphology and crystal structure of the hybrid nanomaterial has been characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy. The electrochemical behaviors of the hybrid nanomaterials based sensor were evaluated through cyclic voltammetry and electrochemical impedance spectroscopy. Under the optimized conditions, the proposed electrochemical sensor showed a fast rebinding dynamics, which was successfully applied to sunset yellow detection with a wide linear range from 5.0×10(-9) to 2.0×10(-6)mol L(-1) and a detection limit of 2.0×10(-9)mol L(-1). The electrochemical sensor has been successfully applied in the determination of SY in spiked water samples, mirinda drink and minute maid, and the recoveries for the standards added are 97-105%.

  3. SIMPLE, SENSITIVE AND SELECTIVE SPECTROPHOTOMETRIC ASSAY OF NAPROXEN IN PURE, PHARMACEUTICAL PREPARATION AND HUMAN SERUM SAMPLES.

    PubMed

    Alizadeh, Nina; Keyhanian, Fereshteh

    2015-01-01

    Two simple, rapid and sensitive spectrophotometric methods have been developed for the determination of naproxen in pure, pharmaceutical preparation and human serum samples. These methods are based on the formation of yellow ion-pair complexes between naproxen and two sulfophthalein acid dyes, namely bromocresol green (BCG method) and bromothymol blue (BTB method). The resulting complexes were measured at 424 nm (BCG method) and at 422 nm (BTB method). The effects of variables such as reagent concentration and reaction time were investigated to optimize the procedure. Beer's law was obeyed in the concentration range of 10-105 µg/mL and 5-85 µg/mL and the detection limits were found to be 0.347 and 0.31 µg/mL for BCG and BTB methods, respectively. The developed methods have been successfully applied for the determination of naproxen in bulk drugs, pharmaceutical formulations and human serum samples with good accuracy and precision. The results are comparable to those of reference methods, and hence are recommended for quality control and routine analysis.

  4. IFCC educational materials on selected analytical and clinical applications of high sensitivity cardiac troponin assays.

    PubMed

    Apple, Fred S; Jaffe, Allan S; Collinson, Paul; Mockel, Martin; Ordonez-Llanos, Jordi; Lindahl, Bertil; Hollander, Judd; Plebani, Mario; Than, Martin; Chan, M H M

    2015-03-01

    In 2011, the IFCC Task Force on Clinical Applications of Cardiac Bio-Markers (TF-CB) was formed, with the purpose of providing evidence based educational materials to assist all biomarker users, i.e. laboratorians, clinicians, researchers, in-vitro diagnostics and regulatory agencies, in better understanding important analytical and clinical aspects of established and novel cardiac biomarkers for use in clinical practice and research. The goal of the task force was to promulgate the same information conjointly through the in vitro diagnostic industry to the laboratory, emergency department and cardiologists. The initial undertaking of the TF-CB, which is comprised of laboratory medicine scientists, emergency medicine physicians and cardiologists, was to address two key issues pertaining to implementing high-sensitivity cardiac troponin (hs-cTn) assays in clinical practice: the 99th percentile upper reference limit (URL) and calculating serial change values in accord with the Universal Definition of AMI. The highlights of both concepts from IFCC statements are described.

  5. Microglial brain region-dependent diversity and selective regional sensitivities to ageing

    PubMed Central

    Grabert, Kathleen; Michoel, Tom; Karavolos, Michail H; Clohisey, Sara; Baillie, J Kenneth; Stevens, Mark P; Freeman, Tom C; Summers, Kim M; McColl, Barry W

    2015-01-01

    Microglia play critical roles in neural development, homeostasis and neuroinflammation and are increasingly implicated in age-related neurological dysfunction. Neurodegeneration often occurs in disease-specific spatially-restricted patterns, the origins of which are unknown. We performed the first genome-wide analysis of microglia from discrete brain regions across the adult lifespan of the mouse and reveal that microglia have distinct region-dependent transcriptional identities and age in a regionally variable manner. In the young adult brain, differences in bioenergetic and immunoregulatory pathways were the major sources of heterogeneity and suggested that cerebellar and hippocampal microglia exist in a more immune vigilant state. Immune function correlated with regional transcriptional patterns. Augmentation of the distinct cerebellar immunophenotype and a contrasting loss in distinction of the hippocampal phenotype among forebrain regions were key features during ageing. Microglial diversity may enable regionally localised homeostatic functions but could also underlie region-specific sensitivities to microglial dysregulation and involvement in age-related neurodegeneration. PMID:26780511

  6. High-sensitivity high-selectivity detection of CWAs and TICs using tunable laser photoacoustic spectroscopy

    NASA Astrophysics Data System (ADS)

    Pushkarsky, Michael; Webber, Michael; Patel, C. Kumar N.

    2005-03-01

    We provide a general technique for evaluating the performance of an optical sensor for the detection of chemical warfare agents (CWAs) in realistic environments and present data from a simulation model based on a field deployed discretely tunable 13CO2 laser photoacoustic spectrometer (L-PAS). Results of our calculations show the sensor performance in terms of usable sensor sensitivity as a function of probability of false positives (PFP). The false positives arise from the presence of many other gases in the ambient air that could be interferents. Using the L-PAS as it exists today, we can achieve a detection threshold of about 4 ppb for the CWAs while maintaining a PFP of less than 1:106. Our simulation permits us to vary a number of parameters in the model to provide guidance for performance improvement. We find that by using a larger density of laser lines (such as those obtained through the use of tunable semiconductor lasers), improving the detector noise and maintaining the accuracy of laser frequency determination, optical detection schemes can make possible CWA sensors having sub-ppb detection capability with <1:108 PFP. We also describe the results of a preliminary experiment that verifies the results of the simulation model. Finally, we discuss the use of continuously tunable quantum cascade lasers in L-PAS for CWA and TIC detection.

  7. Methyl parathion hydrolase based nanocomposite biosensors for highly sensitive and selective determination of methyl parathion.

    PubMed

    Chen, Shizhen; Huang, Jing; Du, Dan; Li, Jinlin; Tu, Haiyang; Liu, Deli; Zhang, Aidong

    2011-07-15

    This article reports the fabrication of a nanocomposite biosensor for the sensitive and specific detection of methyl parathion. The nanocomposite sensing film was prepared via the formation of gold nanoparticles on silica particles, mixing with multiwall carbon nanotubes and subsequent covalent immobilization of methyl parathion hydrolase. The composite of the individual materials was finely tuned to offer the sensing film with high specific surface area and high conductivity. A significant synergistic effect of nanocomposites on the biosensor performance was observed in biosensing methyl parathion. The square wave voltammetric responses displayed well defined peaks, linearly proportional to the concentrations of methyl parathion in the range from 0.001 μg mL⁻¹ to 5.0 μg mL⁻¹ with a detection limit of 0.3 ng mL⁻¹. The application of this biosensor in the analysis of spiked garlic samples was also evaluated. The proposed protocol can be used as a platform for the simple and fast construction of biosensors with good performance for the determination of enzyme-specific electroactive species.

  8. A sensitive and selective determination method of histamine by HPLC with intramolecular excimer-forming derivatization and fluorescence detection.

    PubMed

    Yoshitake, Takashi; Ichinose, Fumio; Yoshida, Hideyuki; Todoroki, Ken-ichiro; Kehr, Jan; Inoue, Osamu; Nohta, Hitoshi; Yamaguchi, Masatoshi

    2003-12-01

    A highly sensitive, selective and simple method is described for the determination of histamine by high-performance liquid chromatography (HPLC) with fluorescence detection. The method is based on an intramolecular excimer-forming fluorescence derivatization of histamine with 4-(1-pyrene)butyric acid N-hydroxysuccinimide ester (PSE), followed by reversed-phase HPLC. Histamine, having two amino moieties in a molecule, was converted to the dipyrene-labeled derivative by reaction with PSE. The derivative afforded intramolecular excimer fluorescence (450-540 nm), which can clearly be discriminated from the monomer fluorescence (370-420 nm) emitted from PSE. Typically, a 10 micro L sample solution was mixed with 100 micro L of derivatization reagent solution, which was a mixture of 0.5 mm PSE in acetonitrile and 0.5 mm potassium carbonate in water (8:2, v/v). The derivatization was carried out at 100 degrees C for 90 min. The PSE derivative of histamine could be separated by reversed-phase ODS column with isocratic elution using acetonitrile:water (82:18, v/v) containing 0.03% triethylamine. The detection limit (singnal-to-noise ratio = 3) of histamine was 0.5 fmol for a 30 micro L injection. The method was successfully applied to the determination of histamine in human urine, and had enough selectivity and sensitivity for urinary histamine quantification.

  9. Highly selective and sensitive surface enhanced Raman scattering nanosensors for detection of hydrogen peroxide in living cells.

    PubMed

    Qu, Lu-Lu; Liu, Ying-Ya; He, Sai-Huan; Chen, Jia-Qing; Liang, Yuan; Li, Hai-Tao

    2016-03-15

    Determination of hydrogen peroxide (H2O2) with high sensitivity and selectivity in living cells is a challenge for evaluating the diverse roles of H2O2 in the physiological and pathological processes. In this work, we present novel surface enhanced Raman scattering (SERS) nanosensors, 4-carboxyphenylboronic acid (4-CA) modified gold nanoparticles (Au NPs/4-CA), for sensing H2O2 in living cells. The nanosensors are based on that the H2O2-triggered oxidation reaction with the arylboronate on Au NPs would liberate the phenol, thus causing changes of the SERS spectra of the nanosensors. The results show the nanosensors feature higher selectivity for H2O2 over other reactive oxygen species, abundant competing cellular thiols and biologically relevant species, as well as excellent sensitivity with a low detection limit of 80 nM, which fulfills the requirements for detection of H2O2 in a biological system. In addition, the SERS nanosensors exhibit long term stability against time and pH, and high biocompatibility. More importantly, the presented nanosensors can be successfully used for monitoring changes of H2O2 levels within living biological samples upon oxidative stress, which opens up new opportunities to study its cellular biochemistry.

  10. Single-layer MnO2 nanosheets for sensitive and selective detection of glutathione by a colorimetric method

    NASA Astrophysics Data System (ADS)

    Di, Weihua; Zhang, Xiang; Qin, Weiping

    2017-04-01

    The rapid, sensitive and selective detection of glutathione (GSH) is of great importance in the biological systems. In this work, a template-free and one-step method was used to synthesize the single-layer MnO2 nanosheets via a redox reaction. The resulting product was characterized by XRD, TEM, FTIR, XPS and UV-vis absorption. The addition of GSH results in the change of solution color depth owing to the occurrence of a redox reaction between MnO2 and GSH, enabling colorimetric detection of GSH. At a pH of 3.6, the proposed sensor gives a linear calibration over a GSH concentration range of 10-100 μM, with a rapid response of less than 2 min and a low detection limit of 0.5 μM. The relative standard deviation for seven repeated determinations of GSH is lower than 5.6%. Furthermore, the chemical response of the synthesized MnO2 nanosheets toward GSH is selective. Owing to the advantages with good water solubility, rapid response, high sensitivity, good biocompatibility and operation simplicity, this two-dimensional MnO2-based sensing material might be potential for detecting GSH in biological applications.

  11. Intrathecal PKA-selective siRNA treatment blocks sustained morphine-mediated pain sensitization and antinociceptive tolerance in rats.

    PubMed

    Tumati, S; Roeske, W R; Largent-Milnes, T M; Vanderah, T W; Varga, E V

    2011-07-15

    Sustained morphine treatment has been shown to produce paradoxical pain sensitization (opioid-induced hyperalgesia) and also causes increase in spinal pain neurotransmitter, such as calcitonin gene related peptide (CGRP), concentration in experimental animals. Studies have also shown that cyclic adenosine-monophosphate (cAMP)-dependent protein kinase (PKA) plays a major role in the regulation of presynaptic neurotransmitter (such as CGRP and substance P) synthesis and release. We have previously shown that in cultured primary sensory dorsal root ganglion (DRG) neurons sustained in vitro opioid agonist treatment upregulates cAMP levels (adenylyl cyclase (AC) superactivation) and augments basal and capsaicin evoked CGRP release in a PKA dependent manner. In the present study, we investigated the in vivo role of PKA in sustained morphine-mediated pain sensitization. Our data indicate that selective knock-down of spinal PKA activity by intrathecal (i.th.) pretreatment of rats with a PKA-selective small interference RNA (siRNA) mixture significantly attenuates sustained morphine-mediated augmentation of spinal CGRP immunoreactivity, thermal hyperalgesia, mechanical allodynia and antinociceptive tolerance. The present findings indicate that sustained morphine-mediated activation of spinal cAMP/PKA-dependent signaling may play an important role in opioid induced hyperalgesia.

  12. Sensitive capillary GC-MS-SIM determination of selective serotonin reuptake inhibitors: reliability evaluation by validation and robustness study.

    PubMed

    Berzas Nevado, Juan José; Villaseñor Llerena, María Jesús; Guiberteau Cabanillas, Carmen; Rodríguez Robledo, Virginia; Buitrago, Sierra

    2006-01-01

    A simple, fast, selective and very sensitive capillary GC-MS method for the simultaneous determination of five antidepressant drugs is described. Fluoxetine, fluvoxamine, citalopram, sertraline and paroxetine belong to the newest and most important drug group termed selective serotonin reuptake inhibitors. Imipramine was used in this method as an internal standard for quantification. Optimum parameters for GC separation were investigated, i.e., flow rate, column head pressure, injector temperature, injection splitless conditions and oven temperature program. MS detection was performed in SIM mode to increase the sensitivity. Stability of the solutions, linear concentration range, accuracy, precision, LOD, LOQ (3.6-41.5 mg/L) and specificity were examined in the presence of excipients for checking the reliability of this method. The robustness was evaluated with a matrix of 15 experiments (seven factors and three levels) using Plackett-Burman fractional factorial experimental design, and Youden and Steiner statistical treatment. The method was applied to the analysis of these antidepressants in nearly all their pharmaceutical formulations, obtaining recoveries between 98.1% and 102.7% with regard to the claimed values.

  13. l-Tryptophan-capped carbon quantum dots for the sensitive and selective fluorescence detection of mercury ion in aqueous solution

    NASA Astrophysics Data System (ADS)

    Wan, Xuejuan; Li, Shifeng; Zhuang, Lulu; Tang, Jiaoning

    2016-07-01

    l-Tryptophan-capped carbon quantum dots ( l-CQDs) were facilely synthesized through "green" methodology, and the obtained material was utilized as a sensitive and selective fluorescence sensor for mercury ion (Hg2+) in pure aqueous solutions. Carboxyl-functionalized CQDs were first green synthesized by a one-step hydrothermal route, and l-tryptophan was then attached to CQDs via direct surface condensation reaction in aqueous solution at room temperature. The as-synthesized l-CQDs had an average size of ca. 5 nm with a good dispersity in water, and exhibited a favorable selectivity for Hg2+ ions over a range of other common metal cations in aqueous solution (10 mM PBS buffer, pH 6.0). Upon the addition of Hg2+, a complete fluorescence quenching (ON-OFF switching) of l-CQDs was evident from the fluorescence titration experiment, and the fluorescence detection limit of Hg2+ was calculated to be 11 nM, which indicated that the obtained environmentally friendly l-CQDs had sensitive detection capacity for Hg2+ in aqueous solution.

  14. Fabrication of bimetallic Cu/Au nanotubes and their sensitive, selective, reproducible and reusable electrochemical sensing of glucose.

    PubMed

    Tee, Si Yin; Ye, Enyi; Pan, Pei Hua; Lee, Coryl Jing Jun; Hui, Hui Kim; Zhang, Shuang-Yuan; Koh, Leng Duei; Dong, Zhili; Han, Ming-Yong

    2015-07-07

    Herein, we report a facile two-step approach to produce gold-incorporated copper (Cu/Au) nanostructures through controlled disproportionation of the Cu(+)-oleylamine complex at 220 °C to form copper nanowires and the subsequent reaction with Au(3+) at different temperatures of 140, 220 and 300 °C. In comparison with copper nanowires, these bimetallic Cu/Au nanostructures exhibit their synergistic effect to greatly enhance glucose oxidation. Among them, the shape-controlled Cu/Au nanotubes prepared at 140 °C show the highest electrocatalytic activity for non-enzymatic glucose sensing in alkaline solution. In addition to high sensitivity and fast response, the Cu/Au nanotubes possess high selectivity against interferences from other potential interfering species and excellent reproducibility with long-term stability. By introducing gold into copper nanostructures at a low level of 3, 1 and 0.1 mol% relative to the initial copper precursor, a significant electrocatalytic enhancement of the resulting bimetallic Cu/Au nanostructures starts to occur at 1 mol%. Overall, the present fabrication of stable Cu/Au nanostructures offers a promising low-cost platform for sensitive, selective, reproducible and reusable electrochemical sensing of glucose.

  15. The structure of the gene encoding the human skeletal muscle {alpha}{sub 1} subunit of the dihydropyridine-sensitive L-type calcium channel (CACNL 1A3)

    SciTech Connect

    Hogan, K.; Gregg, R.G.; Powers, P.A.

    1996-02-01

    The structure of the gene encoding the human skeletal muscle {alpha}{sub 1} subunit (CACNL1A3) of the dihydropyridine-sensitive voltage-dependent calcium channel was determined by isolation of overlapping genomic DNA clones from human cosmid, phage, and P1 libraries. Genomic fragments containing exons were subcloned, and the sequences of the exons and flanking introns were defined. Knowledge of the genomic structure of the CACNL1A3 gene, which spans 90 kb and consists of 44 exons, will facilitate the search for additional mutations in CACNL1A3 that cause neuromuscular disease. 12 refs., 1 fig., 1 tab.

  16. Artemisinin selectively decreases functional levels of estrogen receptor-alpha and ablates estrogen-induced proliferation in human breast cancer cells.

    PubMed

    Sundar, Shyam N; Marconett, Crystal N; Doan, Victor B; Willoughby, Jamin A; Firestone, Gary L

    2008-12-01

    MCF7 cells are an estrogen-responsive human breast cancer cell line that expresses both estrogen receptor (ER) alpha and ERbeta. Treatment of MCF7 cells with artemisinin, an antimalarial phytochemical from the sweet wormwood plant, effectively blocked estrogen-stimulated cell cycle progression induced by either 17beta-estradiol (E(2)), an agonist for both ERs, or by propyl pyrazole triol (PPT), a selective ERalpha agonist. Artemisinin strongly downregulated ERalpha protein and transcripts without altering expression or activity of ERbeta. Transfection of MCF7 cells with ERalpha promoter-linked luciferase reporter plasmids revealed that the artemisinin downregulation of ERalpha promoter activity accounted for the loss of ERalpha expression. Artemisinin treatment ablated the estrogenic induction of endogenous progesterone receptor (PR) transcripts by either E(2) or PPT and inhibited the estrogenic stimulation of a luciferase reporter plasmid driven by consensus estrogen response elements (EREs). Chromatin immunoprecipitation assays revealed that artemisinin significantly downregulated the level of endogeneous ERalpha bound to the PR promoter, whereas the level of bound endogeneous ERbeta was not altered. Treatment of MCF7 cells with artemisinin and the pure antiestrogen fulvestrant resulted in a cooperative reduction of ERalpha protein levels and enhanced G(1) cell cycle arrest compared with the effects of either compound alone. Our results show that artemisinin switches proliferative human breast cancer cells from expressing a high ERalpha:ERbeta ratio to a condition in which ERbeta predominates, which parallels the physiological state linked to antiproliferative events in normal mammary epithelium.

  17. Dronerarone acts as a selective inhibitor of 3,5,3'-triiodothyronine binding to thyroid hormone receptor-alpha1: in vitro and in vivo evidence.

    PubMed

    Van Beeren, H C; Jong, W M C; Kaptein, E; Visser, T J; Bakker, O; Wiersinga, W M

    2003-02-01

    Dronedarone (Dron), without iodine, was developed as an alternative to the iodine-containing antiarrhythmic drug amiodarone (AM). AM acts, via its major metabolite desethylamiodarone, in vitro and in vivo as a thyroid hormone receptor alpha(1) (TRalpha(1)) and TRbeta(1) antagonist. Here we investigate whether Dron and/or its metabolite debutyldronedarone inhibit T(3) binding to TRalpha(1) and TRbeta(1) in vitro and whether dronedarone behaves similarly to amiodarone in vivo. In vitro, Dron had a inhibitory effect of 14% on the binding of T(3) to TRalpha(1), but not on TRbeta(1). Desethylamiodarone inhibited T(3) binding to TRalpha(1) and TRbeta(1) equally. Debutyldronedarone inhibited T(3) binding to TRalpha(1) by 77%, but to TRbeta(1) by only 25%. In vivo, AM increased plasma TSH and rT(3), and decreased T(3). Dron decreased T(4) and T(3), rT(3) did not change, and TSH fell slightly. Plasma total cholesterol was increased by AM, but remained unchanged in Dron-treated animals. TRbeta(1)-dependent liver low density lipoprotein receptor protein and type 1 deiodinase activities decreased in AM-treated, but not in Dron-treated, animals. TRalpha(1)-mediated lengthening of the QTc interval was present in both AM- and Dron-treated animals. The in vitro and in vivo findings suggest that dronedarone via its metabolite debutyldronedarone acts as a TRalpha(1)-selective inhibitor.

  18. Selective loss of alpha motor neurons with sparing of gamma motor neurons and spinal cord cholinergic neurons in a mouse model of spinal muscular atrophy.

    PubMed

    Powis, Rachael A; Gillingwater, Thomas H

    2016-03-01

    Spinal muscular atrophy (SMA) is a neuromuscular disease characterised primarily by loss of lower motor neurons from the ventral grey horn of the spinal cord and proximal muscle atrophy. Recent experiments utilising mouse models of SMA have demonstrated that not all motor neurons are equally susceptible to the disease, revealing that other populations of neurons can also be affected. Here, we have extended investigations of selective vulnerability of neuronal populations in the spinal cord of SMA mice to include comparative assessments of alpha motor neuron (α-MN) and gamma motor neuron (γ-MN) pools, as well as other populations of cholinergic neurons. Immunohistochemical analyses of late-symptomatic SMA mouse spinal cord revealed that numbers of α-MNs were significantly reduced at all levels of the spinal cord compared with controls, whereas numbers of γ-MNs remained stable. Likewise, the average size of α-MN cell somata was decreased in SMA mice with no change occurring in γ-MNs. Evaluation of other pools of spinal cord cholinergic neurons revealed that pre-ganglionic sympathetic neurons, central canal cluster interneurons, partition interneurons and preganglionic autonomic dorsal commissural nucleus neuron numbers all remained unaffected in SMA mice. Taken together, these findings indicate that α-MNs are uniquely vulnerable among cholinergic neuron populations in the SMA mouse spinal cord, with γ-MNs and other cholinergic neuronal populations being largely spared.

  19. Superior selectivity and enhanced response characteristics of palladium sensitized vanadium pentoxide nanorods for detection of nitrogen dioxide gas.

    PubMed

    Mane, A A; Suryawanshi, M P; Kim, J H; Moholkar, A V

    2017-06-01

    Vanadium pentoxide (V2O5) nanorods have been deposited onto the glass substrates by spraying 75ml of 30mM vanadium trichloride (VCl3) solution at optimized substrate temperature of 400°C. The XRD study confirms the formation of orthorhombic crystal structure of V2O5 nanorods. The FE-SEM micrograph shows the nanorods-like morphology of V2O5. The presence of palladium (Pd) in the Pd-sensitized V2O5 nanorods is confirmed using EDAX study. The gas sensing measurements show that the Pd-sensitized V2O5 sensing material is an outstanding candidate for nitrogen dioxide (NO2) gas detection. Obtained results demonstrate that the Pd-sensitized V2O5 nanorods show the superior selectivity for NO2 gas in comparison with other gases such as NH3, H2S, CO, CO2 and SO2 at an operating temperature of 200°C. It shows the 75% response for 100ppm NO2 gas concentration with response and recovery times of 22s and 126s, respectively. Finally, the gas sensing mechanism based on chemisorption process is proposed to illustrate how Pd nanoparticles affect the gas sensing characteristics (response and response-recovery times).